I want to start by saying that I would not be at any point of this conversion without the help of someone I met on this forum. He has helped me termendously with the driver cards for the servos and the electronics of this converison. I will not name him here but he knows who he is..and again I say Thank you.

Well I figured I would post an update to my conversion of a Dyna 2400 CNC mill. I purchased this mill and found that it had some issues after getting it home. It did not display these issues when tested initially but I decided to keep the machine and fix it up. It started as a stepper driven system with it's own onboard controller unit that wasn't real friendly to use anyhow. Here are some pictures of what I had to work with.

http://www.philcole.com/ac/mill_1.jpg

it's not a bad looking machine as seems to be nice and rigid. It has a 10k rpm spindle but I am having some issues I am working out now with it.

http://www.philcole.com/ac/mill_2.jpg

The steppers were driving the lead screws via this delren gear. I had to figure out how to eliminate this in my retrofit plan.

http://www.philcole.com/ac/mill_3.jpg


http://www.philcole.com/ac/mill_4.jpg


http://www.philcole.com/ac/mill_5.jpg

Here is a view of the machine with a cigarette pack for scale...sorry it's all I had around. I need to quit and I am in no way trying to endorse smoking. It kills...and it's killing me..I know.

http://www.philcole.com/ac/mill_6.jpg
This machine has a built in oiler system and an added power oiler built into it...This is nice!

http://www.philcole.com/ac/mill_7.jpg
This picture shows the lead screws...they are not ball screws but they have a quality adjustable nut system that allows backlash adjustment.

http://www.philcole.com/ac/mill_8.jpg
Home switch for Y axis

http://www.philcole.com/ac/mill_9.jpg
Overview of right side of machine showing placement of Estop


Well this is the machine. As you can see Dyna went with a different design of having the stepper drives actually mounted at the end of the axis with the stepper that it drives. All of this hardware must be removed.



So having mulled it over a whole bunch I decided that I would go with a servo drive for this machine. I am intending to do high speed type machining with this mill (if I get the spindle issues sorted out) and I felt that servos would be the best thing for this. I have used a stepper driven machine in the past and really had a hard time with lost steps.

I looked at several places to get servos and most were too much for what this machine needed. I ended up getting servos from www.cadcamcadcam.com I do not have the machine up and running under servo control yet but driving current to the motors to move the axies I am happy with the results so far.


Issues I have completed so far.
1-remove all old controller components
2-design new motor mounts and build them
3-figure out how to drive spindle controller board so I could use spindle.
4-figure out how to reverse spindle direction(it was going backwards) easy fix
5-figure out how to make couplers work with lead screws. I had to turn down the od to remove weight, then bore the ID to allow the locknuts for pressure on the thrust bearing
6-make spacer for inbetween coupler and thrust bearing
7-re-wire existing home switches(temporary until I mount new limit switches)


Issues I still have to address.

1-fix spindle motor and drive (it's currently a mess, motor isn't running right)
2-figure out how to fit all driver boards into the controller cabnet
3-get contuit routed and mounted for running power and encoder wires to each axis.
4-make mounts for new limit switches + and - on each axis
5-make new plate for side of controller cabnet for new ports and cable inputs
6-considering adding dc amp meter for each axis inline with each servo motor to monitor driving amperage...(so I can try to not burn these little motors.)
7-Find gas assisted spring to counter ballence the Z axis head


Here are pictures of where I am at now with this project.

http://www.philcole.com/ac/mill_10.jpg
THis is the spindle drive motor getting ready to go to the motor rebuild shop. It needs some TLC

http://www.philcole.com/ac/mill_11.jpg
This is the head assembly removed and stripped down a bit. I suspect the potentiometer(spelling?) is bad but am waiting until the motor comes back before replacing

http://www.philcole.com/ac/mill_12.jpg
X axis servo mounted and ready to go...except for encoder wires and power wires

http://www.philcole.com/ac/mill_13.jpg
Y axis servo mounted and ready to go...except for encoder wires and power wires

http://www.philcole.com/ac/mill_14.jpg
Z axis servo mounted and ready to go...except for encoder wires and power wires

http://www.philcole.com/ac/mill_15.jpg
Close up of drive coupler. This motor mount bracket needs adjusting still to close the coupler. Thats another thing I need to add to my list.

http://www.philcole.com/ac/mill_16.jpg
Controller cabnet. not a lot of room once the other power supply gets mounted. I need to tidy up all of this wiring still and make room for the new controllers.

http://www.philcole.com/ac/mill_17.jpg
Close up of one side of the existing X axis home switch

http://www.philcole.com/ac/mill_18.jpg
Close up of the other side of the X axis home switch

http://www.philcole.com/ac/mill_19.jpg
Close up of the nut assembly visible from back side of the Z axis

http://www.philcole.com/ac/mill_20.jpg
Different view of Z axis assembly

http://www.philcole.com/ac/mill_21.jpg
This is just another view of the XY slide.

I will try to update this post as things progress. I still have a lot of work to do.

I wanted to make this post as there is not much info on here or the net about converting this machine. I can and will try to help those with questions but I will say that this is my 1st machine conversion and I really don't know much about the electronics side...but I will try to help.

AC

looks to me like your doing a first rate job.. keep thoes beautifull pics a-comm'n

Well I received some not so great news about the spindle motor. It seems that it may be toast. They are going to try to fix the commentator but whoever owned this thing before put lots of new brushes in it but never had it serviced...so the brushes have eaten there way through most of the comm.

Does anyone have any sudgestions on what I might be able to do to replace this motor?

I cannot seem to find any .5hp 90v dc motors that are this size. The area for it to mount is about 3.5dia max by about 4.5Length. This may be a show stopper if the rebuild shop cannot fix it.

I am open to any great ideas.

Would possibly a servo motor fit in there? Anyone?

Thanks
AC

MCG ID33001
4.69 lb-in @ 6000 rpm ~ 0.44hp
The length is 4.78 so you may not be able to fit it


http://www.mcg-net.com/electric_motors/downloads/brush_motors/ID33000_DC_brush_motor.pdf

Aaron

Thanks for the info. I will look into those and see if they might work.

Thanks again.

AC

UPDATE:

I had removed the spindle motor due to an issue with the speed and torque variance while cutting (manually turning couplers at this time) light passes in aluminum. I found that the motor was in very bad shape.

I now have the newly rebuilt motor in the spindle and I cannot believe the change in performance. This little motor now has way more RPM than it had before and it has power to spare.

I now have great concerns about the bearings in the spindle itself. If the bearings in the motor were this bad then I bet the ones in the spindle cannot look much better. Although the spindle feels smooth in rotation by hand I think I will tear it down for a full inspection to make sure there are not any issues. I do not want to take any chances at 10,000rpm.

I recommend to anyone who has aquired one of these Dyna 2400 mills to tear down the head assembly and check the motor and spindle bearings. These machines are setup for 10,000 rpm running and by the looks of the motor in mine they do this and they can do this for a long time! When I bought this machine there were 8 available from the place that I bought it. I took my time and picked the one that was in the best mechanical and cosmetic shape. It was a lot cleaner and looked like it had been maintained much better than the other machines. These little machines in my opinion are built extreemly well and are made to run for a long time. I find that many companies have used these over the years to produce some amazing production type parts. This means that when you get one you should go through it throughly and inspect all mechanical components.

The thrust bearings on my machine seem to be in good shape as well as the gibbs and backlash nuts. I have seen one of these machines online where the thrust bearings have been in peices when the user removed the end motor mount to inspect them.

The built in oiler system in the base of the machine(the XY casting) seems to hold oil and works well. I have inspected the oil lines and they all seem to be free of clogs and not leaking. I will be inspecting the automatic power oiler system as this project continues.

I decided to use a flexible conduit type hose to run the encoder cables and servo power lines out to the end of the motors. This will serve to protect the lines from oil, dirt, and chips generated from the cutting process. Over time oils and solvants will break down and make the insulation of these wires brittle. Although this takes time...lots of time, I feel it is worth the extra work to protect these lines.

Over the next week I am planning to map out the controller cabnet as to where each of the components will be mounted and where wire will be routed. This is going to be tricky as I need to make sure the airflow is going to be optimum for all of the components in the case.

Thanks for reading and I am open to any ideas and suggestions any one has with this ongoing project.


PS sorry no pictures this time.
AC

Hi there, I have just picked up a dyna 2400 myself and am in the process of a stepper conversion. Have you been able to get an increase in useable bed travel by removing the original motors?

regards

Scott

Scott, At this time I am using the exiting screw mounts and I have not yet figured out how to increase the bed travel as the bed currently limits out flush with the end of the gibbs in each direction. Creating new screw mounts and replacing the screws you could I guess increase the travel but the issue I see with this is you will then be starting to expose the top of the gibbs and this has grooves cut into them for distribute the oil. You could then get chips into this area as the way wipers would not be working.

If you wanted to increase the travel in X I think you would need to make a new table and longer gibbs/ways to stay in contact with the way wipers to keep from getting chips into the system. I could be missing an option as I have not really looked into this and I am just going from memory here.

I will try to answer any quesitons you have along the way if you need any assistance.

AC

Hi Alex, found your thread. Looks awsome. So for those of you out there, I am rebuilding a Dyna 2200 benchtop VMC. My first CNC project, I have new steppers, new xyoltex drivers, and a breakout board from cnc4pc.

Here are my questions

When I run the C11 breakout board in conjuntion with my driver, I can barely get the steppers to turn, anyone got any tips on that one? So I bypassed the breakout board, which I am starting to belive was a waste of money anyway, and things are running smooth.

Does anyone know where the wires from the limit switches go? Can I plug them into the xyoltex driver, or do they need to go into the breakout board?

Here is my biggest question. The anti backlash nuts on this machine seem to be a spring loaded plastic, maybe derlin? I don't like em. I have an acme lead screw which I think is 1/2" by 10, but I am not sure because the major dia of the screw is .475" or so. It looks much like Alex's lead screw. I can get the steppers to go about 40 ipm, but only for a couple of inches then it sound like the lead screw is binding in the nut. I wish to keep the existing acme and remount a different nut, on the cheap by the way, afterall I am new teacher. Your ideas are very welcome. Alex suggested the rolled ballscrew homeshopcnc.com. But too pricy right now. Like I said, I am a teacher, not a Trump. I was think two steel nuts with a pre load of some sort, but the machine did not come with a oiler.

By the way, Alex, you are doing an amazing job, I will try to get some pics up soon.


dave

Woodturn, If your screws are like mine and are origional then they should be a 2.5mm pitch that is .098425197 per revolution. With the way they have the end bearing mounts setup and how the backlash nuts are mounted I would be supprised if they were binding but you never know. I would try to see if this was the issue by loosening up the gibb adjustments and also the anit-backlash nut and reomove the stepper you have mounted. Then try turning the coupler you have installed by and to each end of the travel of the table. Does it seem like it is binding? THen slowly start to tighten everything back down in small incriments while turning the coupler from one end of the travel to the other. I know this will get old but it is the best way I figure to track down if you have a binding issue in your setup or not. If you removed anything just make sure you get all peices back where they were when you re-assemble.

As for the limit switches. If you are using Mach software you will be running the limit switches to the computer. This means through your breakout board. I believe the Xylotex board has terminals for you to use for inputs. So in that case you would run them to the Xylotex board. There documentation should describe this. You also need to keep in mind how many pins you are going to use up in your limit switch method. If you loop the (+) and (-) switches together then you will only use up 3 input pins for your six limiti switches. But if you want to have independant + and - inputs into mach then you need 6 available input pins into the computer. THis may mean a 2nd parallel port card in your pc. This is the method I am most likely going with due to other inputs I will be using.

I attached my wiring diagram that I am going to use for my new limit switches once I get the new mounts made. I ran it past the electronics guru that is helping me on this project and he said it looked like it should work good. It uses a continuous +5v signal through the switches. That way if a switch gets tripped or wire gets cut the machine will stop. If you use a +5v when the switch is activated then you run the risk of a wire being cut and you not know it and the machine runs through the limit and crashes. ...That would be bad!


Last night I got the power supply mounted back into the controller cabnet and I preped for mounting the drivers. I just need to go pick up some standoff material and I will have the drivers mounted and set to go.

Hopefully I will get this done tonight.

AC

I also have a dyna 2400 mill that I am in the process of converting. I was hoping to use the original stepper motors, but it looks like I might end up replacing them with something a little more precise. Has anyone come across a stepper motor model that will bolt into this machine without too much work?

So I got my steppers from automationdirect.com. about 19 bucks a peice. They are NEMA 17s and have about 83 ozin of torque. they mount up OK with some screw that I bought at Ace Hardware, but I forgot the pitch of the screws. The steppers are nothing special 1.8 degree four wire, but so far they seem to work well with my xyoltex driver. If you mico step your drive, you can get a higher resolution, but then you will probably want to get rid of you gear reduction. Oh, I also had to cut the arbor of the stepper to put my drive gear on it. I hope this helps. Oh by the way, I did not use the original 8 wire steppers were impossible to get the spec sheet on so that is why I went with the four wire from automationdirect.com.

Back to my lead screw issue... I pulled off the X table and the ways seem to be in good shap and slide easy when the lead screw is out. When I thread the lead nut on the lead screw it feels as if the nut is a lock nut, it is really stiff, so I think that I will make an antiback lash set up if I can find a nut that fits. By the way AC, I think my lead screw is the same as yours a 12mm 2.5. The distance between peak to peak is about .100, which translates into 2.5, assuming my math is right. Do you know where I can find a lead nut that will fit? Thanks

On the electronics issue... I will deal with the limit switches after I get my lead nuts figured out, but thanks for the info. I think I did waste my money on the breakout board, I hate wasting money!!! But who knows, it might be useful later on.

Well I am going to try to find a lead nut, maybe dumpstercnc.com??

Thank you in advance
dave

It sounds to me like your ainti backlash nut is adjusted too tight. There is an adjustment screw on the backlash nut that is used to adjust the tention on the screw. If it is adjusted too tight then the screw will be hard to turn. If you scroll up look at the picture of the Z axis nut assembly. The big allen screw that is sticking up is the adjustment screw. Turn it CCW to loosen the tention and CW to take up the backlash if I remember correctly.

I have looked over the anti-backlash nuts that are in place on my machine and although the inners are some sort of delren or the like they seem to be real solid. There are lots of thread engagement to distribute the weight and I have taken some test cuts in 01 tool steel at about .035 deep with an .125 flat endmill and it seemed to hold fine without feeling weak at any point. NOTE: I was turning the couplers by hand to try to feel the rigidity(?spelling) of the machine. I was quite impressed as the machine didn't seem to have any issues with cutting the steel and left a pretty decent finish.


As for an update on the progress of my machine I received the aluminum that I will be using to make the wiring mount plates. I have not figured out the complete design as my origional plan was scrapped by a clearance issue with the chip pan. Oh well I guess it's back to the drawing board there. I am however now ready to get the control cabnet cut to allow the wiring to come into there.

I have one controller board mounted and I have both power supplies mounted back in. I have the holes ready for the other servo controllers ready but I have to get the right standoffs. We are going to use plastic ones not the ones shown in the pics.
http://www.philcole.com/ac/Control_Cabnet.jpg

Well I'm tired and going to bed. See ya'll later.

AC

I wish I have the same system as yours, but there is no adjustment for mine, I'll try to get some pics tonight, got to go,
dave

Woodturn - since you have a 2200 machine, you have different anti-backlash nuts than Alex does with his 2400. the 2200's have spring-loaded nuts, the 2400's have screw-adjustable nuts.

The only suggestion i have for you is try oiling your screws. That might allow higher speed. You could also try replacing the spring in your anti-backlash nut with a less powerfull one.

If you're dead-set on replacing them, i would look for a similar nut as the 2400's use. believe it or not, plastic threads would be my first choice, followed by brass/bronze. steel would be a last-resort option. Likely to gall on your screws.

file:///C:/Documents%20and%20Settings/Dave%20Stevens/My%20Documents/My%20Pictures/Img0029/lead%20nut.JPGHere are some pics, I hope they went through
dave

I am glad my pics went through. I have tried to take the screw off and run the nuts by hand, but my hand gave out about a quarter of the way in, it feels like I need to wench the nuts on. I am debating on getting rid of the back half of the screw and facing off the other half to have less thread engagment, but then I will not be able to find a replacement if it does not work, I can't find these #$%$### things anywhere

AC, are you sure that they are 12mm with a 2.5 pitch? I can find a source for these.

What type of lube would you all use,

thanks again.

dave

Something definitely sounds wrong there. Running them on by hand should go pretty smoothly.

Did you try running each half on independently? does one half run on better than the other?

By the way, i don't know if this is just how you took the picture, but that nut looks like it's not assembled correctly. You shouldn't be able to see much, if any of the thread in the middle of the nut. The 2 halves should be closer together. Unfortunately, this will make the preload higher, and make it even tighter. Perhaps the 2 nut halves are clocked 180 degrees, and maybe that's causing it to bind?

I will have to go back and check my notes when I get home today. I do know the ones I have are for a fact 2.5mm I called dyna and asked them specifically about them before. You can always contact DynaMechtronics and setup a support account with them and order parts through them. They may be able to get you the type of leadnuts that the 2400 has with adjustable backlash.

I guess if I were going to do it I would probly just save up and replace the existing screws and nuts with nook. As I said before I don't think the work envelope of this machine would justify the expense of ground ball screw.

You could easaly replace the lead screw with a new one. Just get a more common screew and have the ends turned down to mount and you should be set. At least that way you would be able to get parts easier for it. checkout this site and search on ACME lead screw.

http://www.mcmaster.com
AC

Yea I think you're right, nooks would be the best in this situation. I plan on installing half of the nut and do some careful adjustment of the gibs and call it like it is, when I get more $$ I will probably retorfit the machine to nooks or something like it...I wonder it I should get some gaint NEMA 43 steppers??? would that solve this problem.... with say 750 ozin of torque?? Probably not the best fix, but it's fun to think about kind of like putting a V8 motor on a chainsaw. OK enough of that, time to get back to work.
dave

I was contacted with a question about how the head is held onto the round column of the mill. Here is a picture of the screw with the locking cam to help you guys understand how this works a little better.

http://www.philcole.com/ac/mill_column_lock.jpg

This is an image of the spindle head assembly from the bottom. The round hole you see is where the vertical cylinder goes through to hold the head. as you can see there is a little cam in here that is affected by the lever on the right side of the milling head. When you tighten this lever it pulls this little locking cam into contact with the mounting cylinder and clamps down on it locking the milling head into place. All in all with this machine I feel that this is the weakest point in the design/regidity of this litlle mill.

I have taken manual test cuts in Aluminum, copper, and 01 tool steel and so far I have found that this little machine should be able to work with all of these materials without issues of regitity coming into play. I feel if this mounting method were changed then the performance of this mill would be increased but it does ok with the current configuration.

I hope this helps

AC

Hi, I have not taken my head off yet, but thanks for the heads up.

I think I have made my lead screw situation better by running lapping compound up and down the thread with a cordless drill. I plan to assemble the x and y to see it I helped or hurt the situation.

thanks,
dave

Just make sure you get those things as clean as possible when you are done. If there was any of the compound left on there it would probly ruin your screw in short order under program control.

I am however glad to hear you may have it resolved or at least more usable. I am still trying to figure out how I am going to buld my wire mounts that are going at the end of each axis by the servo.


AC

After some gib adjustment, I got my mill to rapid at about a comfortable 20 ipm, any faster I just get a bunch of vibration.
dave

I have made some progress on my mill this wkend but I have not been able to put any pictures up yet. I am trying to figure out why my web server went down. This is why my images are no longer showing up. I will try to fix this issue asap.

Thanks
AC

u can upload them here, just go to manage attachments and find the pics on your computer. that would be better anyway since it will load faster

Alex, do you know the voltage rating for the DC spindle motor? Im pulling out the old drivers and fitting new steppers and controls and want to control the spindle motor through mach.

Scott

I pulled out the motor and checked, 80V DC. Am I right in saying that the smaller of the three AC to DC convertors provides power for the spindle motor?

regards,

Scott

Yes, In my machine the motor is an 80v. I believe there are many controllers out there that should work for this as it seems there is a standard of 0-90vdc for variable speed drives and boards out there. If you went up to 220 then they go from 0-180v I beleive.

What exactly are you wanting to control from mach? I have isolated the two wires on my spindle driver that are used for switching between manual control of the spindle to program control. I have not figured out the speed control of it yet but I believe it is there somewhere. On my machine there is a switch on the front of the control cabnet by the power switch that says Program control, Local control. When the switch is in local control then the spindle is controlled by the switch on the head of the mill. When it is in program control then there is a wire wich turns the spindle on when +5vdc is applied to it.

Take some pictures of your spindle control that shows the details of it and it's connections and we can see if it is the same one that is in mine. If so I can tell you which wires control these features.

Hope this helps.

AC

So I got my mill running, kind of, everytime I rapid over to 0,0,0 I get stalled out, half the reason is my lead nuts, but I have a strong feeling that my steppers are under powered. I have NEMA 17's with 83 ozin of torque, running a 10:1 gear reduction and full step on my xyoltex driver board. Here is my question...Would it be better to invest in either some beefy steppers or a new lead screw system. I am leaning towards steppers Something with about 250 to 300 oz in of torque. Thanks
dave

I would assume that you would be happier with larger steppers as the 17's are pretty small. I did not use steppers in my conversion but small servos and I just did some initial testing tonight of the custom servo drivers and all seemed well so far. I do not think that you will be happy even with better screws if you use the 17's for this. Mabe someone with more stepper experience could chime in with more input.

AC

Well we got more work done on the mill. While I was waiting on the electronics I started making some brackets that were needed. I have purchased some flexable sealed conduit that I intended to run the wires through out to the servos. I have been having trouble trying to figure out how to mount the flanges out at the end by the servos but I think I am close to figuring out how I want to run them. In the mean time I had to cut a hole in the side of the controller cabnet to get rid of the origional plug cutouts. So I got some abrasive cutoff wheels for my dremel tool and went to work.

1st I measured the area I had to work with and made a new aluminum plate that will act as my new surface. I measured the adaptors that needed to attach to this plate and made sure they were going to fit. I used our Haas mill at work to circle interpolate the holes for the contuit connectors and to drill the mounting holes. After this was completed I then was able to determine how much material I would need to cut out of the side of the control cabnet.

Here is a pic of the new plate installed on the mill.
http://www.philcole.com/ac/Mill_Pic_002.jpg



The guy that is helping me with the electronics has several options available for me for how we were going to run the encoder wire connectors to the driver boards. The servo motors I bought had connectors that use an Svideo cable connection. we discussed running the wires strait into the driver cards but I wanted the wiring to be clean and easy to work with. So I decided to use some of the svideo mounts that we purchased. I started by taking small peice of aluminum and laying out how the ports would fit. After I had my plan I then measured and drew up the layout using Cad and then cut the plate on our Haas mill at the office. This plate now allows me to have the weight of the cable on the plug board as I call it instead of having all the weight of the cable pulling on the pins of the driver cards. This also makes the wiring clean and simple.
Here is a pic of this plug board.
http://www.philcole.com/ac/Mill_Pic_003.jpg


Thursday evening we were able to mount the driver cards as I finally found some plastic standoffs to use to keep the driver cards isolated from the controller cabnet. We wanted to keep them isolated incase of any possible shorts which might distroy the card. I just ordered my breakout board that I am going to use and it has not arrived yet so we just had a small test cable that will work for 1 axis only. We hooked up each of the axes one at a time and tested the system. After fiddling with the motor tuning in Mach we got the system running smooth. I was conserned about the Z axis with these small sevos but it seems to run well. Last night after I did the math for the gear reduction and the pitch of the screw I was able to plug in the accurate numbers and run the axis. I currently have my speed limited to 85ipm and this little thing looks like its doing that accuratly. Once we get the other axes under control I will be doing further testing to prove out the speeds and accuracy of my ratio calculations.

I had a small aluminum project that I was cutting on the Haas at the office and I was not able to finish it friday. I decided to bring it home as all I had left to do was to deck off the back of the peice. I mounted the part on the mill and used the X axis as a power feed to finish milling the material I had left. I needed to remove about .150 from the part. I used a .250 4flute endmill and set my depth of cut at about .05 This is in inch by the way. I set the jog speed to about 10% which is 8.5ipm. The stepover I ran was about 40% of tool diameter. The mill made this cut and didnt complain. The vibration was a little more than I liked so I ended up backing it down to about .025 per pass and stepping over about 60% of tool diameter. I then ran the mill at 15% jog speed which is 12.5ipm. The mill took this with no problems. The cut sounded good and looked good. This was the 1st real test I have had with this machine after the spindle rebuild. So far it looks like I am going to be very happy with this mill. My rapids seem like they are going to be around 85ipm and the cuts are smooth and clean. I can hardly wait to get the whole thing under program control so I can test some high speed machining at around 60ipm which is my goal.

Here is a pic of the mill after I cut. Yay! see the chips!
http://www.philcole.com/ac/Mill_Pic_001.jpg

Well I have to go now. I have lots of work to do. Before the breakout board gets here I have wiring harnesses to make. 1 to run the 5v power to each of the driver cards and all the stuff for the breakout bard.

Later for now.

AC

Just a quick update for everyone. I am still here and working on this conversion. Schedules have been busy and slowed down progress for the moment along with a small electrical glitch that we are tracking down in the controller. I will hopefully be posing and update and some more pics of the controller as we continue to wire it up and get things going.

More to come soon....I hope!

AC

I too have been busy with life, I am waiting for new steppers to come in the mail. 269 oz in, I'll have to make some new mounts and maybe a resonance dampener, gotta go
dave

Hey

I also have a Dyna 2400 that is in excellent shape but has no electronics, only the spindle motor and I want to upgrade it to something faster..

I am very interested in what progress you have made and what mods you have done to improve the old system that it originally had.
What you have done up till your last post looks excellent !

Kel

Well I guess it's update time again. I just now had some time to get back to work on my mill project. I was chasing down some wiring issues and I finally got that all figured out just the night before last.

I found I was having some issues with noise in my system. This was without the spindle turned on. So I made some new cables up and started tracking stuff with my friend who knows the electronics part of all this. We found I was getting some noise on my step and direction pins to the drivers. with the new cables everything was fine until I turned on the spindle. THen I started getting noise in the signals again. We messed around with it a bit more before calling it quits.

Symtoms:
Faulting axis drives at reasonable speeds
Power light flickering when running the Z axis at times.
When we would turn on the spindle the Y or Z axis would creep, and it would creep faster and faster the more spindle RPM we gave it.

Steps to test:
We replaced my 24v power supply with one that was rated at more power.
We removed the step and direction connections to the driver cards to see if the noise was coming from the encoder lines or the step and direction pins.

Results:
Replacing the power supply resolved the Z axis faulting at such low speeds. The power supply I am using is 24v and my servos are rated at 30v so I am not at max performace for these servos. I will get a better 30v PS later.

When I disconnected the step and direction cables the motors stood still while we ran the spindle at any RPM. We then concluded that the noise was with the Step and Dir pins. The simple way of resolving this issue is to move the servo control components into a seperate enclosure to isolate the spindle driver board. This should remove the noise from the spindle and the servo drivers. I have gutted an old VCR case that now houses the servo control system and its electronics.

We also found that the axis driver boards were not liking the way the 5v PS ramped up to power. So I setup the power switch to turn on the fan, 24v ps, and 5vps, but the 5v does not get sent to the drivers until another switch is turned on.

Each of the driver cards has a fault LED that lets you know when the drive has faulted. There also is two pins that are used to reset the drive after a fault. I made up some cables and drilled 3 holes in the case for the 3 LEDs and then mounted 3 momentary push button switches to short the two reset pins in case of a fault. So now I can reset a drive with ease in case of a fault. I just have the wiring to finish up on the last LED for the Z axis and the new controller case will be done.

Now that the two controllers are seperated I need to come up with a new 5v PS for the spindle enclosure as I had to take the other one to put into the new servo enclosure. So I have not been able to test with the spindle running again, but we are confident that this should solve the issues we were having.

Currently the mill has limit/home switches on the axies for 1 end of travel so I still have to get my new switches mounted for the other end of travel. I need to get the mill up and running so I can make the brackets to mount them though.

The mill is under power now and I have run some programs to test its motion and it is nice and smooth and quiet too!

I will try to get some more pictures of the new setup and get them posted soon. We have been busy around here so I have not been able to put a lot of time into this project until just recently.

Thanks and let me know if you have any quesitons.

PS if anyone has any sudgestions on trying to isoloate and remove the noise we are getting any help would be greatly appreciated as I don't know much about the electronic part of all of this.

AC

Well, I think I found that this issue I was having with the Z axis was not noise but the servo driver itself. I am going to pull the driver card so we can try to track down what is wrong with it. In the meantime I have ordered a Gecko G320 to test with to see how it drives the Z axis of this machine compared to the drives we have put together. I will get some pictures as time allows and report the results of our tests.

AC

How did my thread end up in this "Knee Mills section. It is a benchtop mill with no knee? I started it in Benchtop mills? How did it get here?

Anyone?

I just got stock to mill up some new mounts for my 269 oz in steppers. Hopfully we will have this thing up and running my the end on the year. It is like one step foward two back around here.
dave

Hi Alex. This is awsome to see what you are doing. I bought a 2400 a few years back and never did much with it. Fired it up a few times and shut it off then used it for a dust magnet. I finally have a need to get it running and now I see what you are doing. You just cut my work down to almost nothing. THANKS! My machine is in excellent shape with very low usage. I only had two problems while playing with it. First is one of those Delrin gears broke and the controller that came with it would error out on random occasions. The first was an easy fix, the second is why I never used it and wanted to convert it. I do have a question for you. Do you know what kind of backlash you have? I want to use mine for circuit boards as well as regular machining and low backlash is an issue. Hope to be in touch as this moves along. Keep up the good work!

Rodger

It is going to depend on how yours is setup. If you look at the pictures in my post you will see one of the Z axis backlash nut. If yours is of this type then it is adjustable. I have not done a major ammount of work in getting this dialed in yet as I am still working on the z axis driver issue right now but on my X axis using my digital indicator I have been getting a consistant reposition of .0005. I tested the Z axis just the week before last and I am getting the same results with it.

These machines are built well if you have one that has the same construction as mine. Some have a little spring loaded nut that isn't really adjustable. For units with that type of nut I cannot comment about as I am unfamiluar with them. With my unit and the ones like it from what I gather they are supposed to be able to have a repeatablility of somthing crazy like .0002 in there origional configuration.

I will try to help with what I can. Just post any questions you may have and some one will most likely be able to help.

AC

Hi guys, just finished the control upgrade on my dyna 2400 and am setting up mach 3. Could anyone suggest the correct proceedure for removing backlash from the x and y axis on the 2400?

Ive had the table apart to check the ways etc and noticed on the screw nut a large hex bolt, is this used to control backlash? Anyone know how much load i should put on the nuts at the end of the screws?

Scott

Sorry, I have the plastic spring loaded type. So I have no idea.
dave

At this point I have adjusted the nuts at the end of my screws until there was no linear movement anymore but also not so tight that it created major resistance on the rotation of the screw. If you have them too tight I figure you will wear out the thrust bearings pretty quick. As for the backlash screw on the block I used my indicator and adjusted this screw until there was no backlash but again not so tight that it made it too hard to turn the screw.


HTH
AC

Hey Guys,

Does anyone know what the original spindle motor transformer was rated for on the 2400? Mine did not come with any electronics(just the 80vdc motor with snipped off wires) at all so we wound one from an old transformer. When testing to figure out the DC voltage to achieve 10000 rpm (at the spindle) with a Variac and a tach we came up with 55 volts AC converted to DC with a rectifier circuit gave us 10000 rpm. We built the transformer to put out about 3 amps.
I was wondering if anybody has the original specs to see if we are close or not.
Another question I had was when the spindle is under load or cutting conditions does the spindle motor rpm decrease much or does it have a circuit of some kind to keep it at a constant rpm continuously? With the transformer and rectifier circuit we made the rpms do drop somewhat under heavy loads.We also made a speed controller that works but we blew one transistor so far. It has been replaced and added a larger heatsink for the transistor but havent tried it again yet and we are not sure why it blew yet ??

Any info would be appreciated. I am just learning electronics basics from a friend so this is all new to me but very interesting.

Thanks Kel

Hey Kel,

I converted my mill from 110v to 240v. One thing i did was replace the spindle control and powersupply. I puchased an all in one unit that basically plugs into the exisiting wiring loom. Its called a whisperdrive, can look up the product code on monday. It lets me input either 110 or 240v and has trim pots that let you control heaps of things like ramp in and ramp out, speed control, auxilary relay switching from the pc, spindle lock and overload protection. I also have the exisiting spindle driver board lying around

Scott

My spindle will bog under load. Sorry I don't have much time today guys but just wanted to let you know.

AC

Hey Kel,

I converted my mill from 110v to 240v. One thing i did was replace the spindle control and powersupply. I puchased an all in one unit that basically plugs into the exisiting wiring loom. Its called a whisperdrive, can look up the product code on monday. It lets me input either 110 or 240v and has trim pots that let you control heaps of things like ramp in and ramp out, speed control, auxilary relay switching from the pc, spindle lock and overload protection. I also have the exisiting spindle driver board lying around

Scott

Your "whisperdrive" sounds interesting. Do you have a link to it ? Was the original spindle driver board not adequate enough ?

Kel,

http://www.kbelectronics.com/manuals/kbws.pdf

The existing spindle driver runs on 110V, I wanted to get rid of the huge 110-240v transformer that was atttached to the side of my mill since everything else is now 240v. The new spindle drive is much more compact and lets me input either 240 or 110v. There is some drawbacks inputting the higher voltage but wont be a problem for you running 110v. Ive had my spindle runnning nicely for a while now.

Here are a couple of pictures of my Dyna 2400.

As you can see it was pretty much stripped of all electronics when I got it. It is in excellent mechanical condition though and as others have stated these machines look like they were well built. It has good backlash adjustment and leadscrew nut adjustment for better accuracy.

I decided to go with stepper motors so I chose the Xylotex 4 Axis Kit. It should be in this week sometime. This should be an interesting project. I plan to make my motor brackets etc etc with the machine manually so I can get a feel for what kind of loads you can put on the spindle without burning up the bearings.


Kel

Kel, I made engineering drawings for the motor brackets based off the old brackets to fit nema 23 motors to the exisiting gears. I made the motor mounts myself and they work very well. Its been a week since ive had my mill running cnc. Rapid speed is painfully slow using the original gear reduction in the mill. I am about to make motor blocks that will direct drive the leadscrews trhough couplers.

I also have cad files somewhere with my motor mounts, if you need them.

AC

Hi Alex, are you direct driving the lead screws or running through the reduction gearing? Im finding rapiding my mill slower than a wet week.
I want to do something similar to this build i found searching on the net:

http://www.grifftek.com/images/dyna2400remec/

Some movies there too showing the rapid speeds, my only concern is introducing extra backlash through the coupling. Ill order a coupling set and see how it feels.

Scott

My servo runs with a 2.8 to 1 belt reduction. If you look in the images of the post you will see the little black boxes that the servos are mounted to. Inside there is the belt reduction. I ordered some LoveJoy couplers and used my lathe to turn them down for attaching to the lead screws. I had to bore the ID to get them to mount on the screw. You can see how they are turned down in my pictures as well. The largest reason for me turning them down was to reduce rotating mass for the servos and drive. They seem to be working well. I believe I have a cad drawing of the couplers if you need.

AC

Hey Guys, Any CAD files you may have would be greatly appreciated. It would give me a start on what I have to make .

I was thinking of going direct drive from the steppers to the leadscrew with a homemade coupler. I guess whatever way you decide to couple the motor to the leadscrew you just have to keep backlash into consideration. That is why I was thinking of going direct drive. I allready have the backlash on the machine adjusted to allmost nil.

Kel

I will try to get the files posted tomorrow when I get a chance.

AC

I will try to get the files posted tomorrow when I get a chance.

AC

Thanks Alex

Kel

what format would you like them in?

AC

Hi Alex, DXF or IGES files would be fine.

Kel

Hi Alex, DXF or IGES files would be fine.

Kel

A PDF file would be nice to have if you can convert it also.

kel

Those of you who have this machine and are running stepper systems I just wanted to chime in and ask you what you thought of the stepper system running this machine. What are your speed and feeds like? How is the noise from the motors? What have your part finishes been like using the steppers?

I am thinking of getting a stepper system to compare, and once we get the servo drivers up and running I would be able to compare the two.

Thanks

AC

Here are some files for you guys. I tried to dimension the holes that are where it mounts to the mill plate. The other holes are for mounting my servos and other brackets. I didn't have much time to clean these up for you so if you need more detail or a cleaner bracket PM me and we will see what we can do for your application.

Let me know if you have any questions or issues.

AC

PS files are in Inch

Wow, do I feel like a slacker or what!! I am still working on those motor mounts for my NEMA 23 269 oz in steppers. Well, actually, my friend is milling them up on his bridgeport. I'll let you know how they work when I get them hooked up. That should be this time next year at the rate I am going.
dave

Thanks for the files AC . You made really nice brackets. Did you draw anything else up ?

I recieved my Xylotex 4 Axis Kit today so I guess its time to get to work on this project. I have to make my brackets and couplers next so we can give it a bench test. Then I am going to mount all of my electronics ( Driver board, power supply,spindle transformer, AC/DC converter, spindle speed controller, fans, etc in a computer case. This should keep me out of trouble for a while.

Kel

Sounds good, so what are you going to do with the 4th axis? Just wondering because I might eventually run a servo for some ridgid tapping. But at the rate I move, who knows..

I will eventually make a Rotory table for a 3 jaw chuch or a collet system so I can do 4 axis machining. I would make it so it would run horizontally.

Kel

Hello: I enjoyed your discription of upgrading the 2400 mill. I have 3 of these mills and they are the way dyna made them. I only have 2 running right now. I have in the past gotten around the spindle motor running problems by using a outside dc power supply and not trying to use the main board to drive the spindle. I lose the ability to program spindle off or on but it beats not having the machine. Thanks Tony C.

Hi all. I just thought I'd chime in and say that I've had a 2400 for about seven years, and for seven years it's been gathering dust in my workshop. It was in a pretty sorry state when I got it home, then I stripped it to clean (all the oil lines were clogged with hydrolyzed oil and the sump was filled with this yuck). Then I discovered why the spindle motor wouldn't turn, it was because the controller had been removed. Then I discovered why the controller had been removed, it was because the drive disk to the spindle had shattered (probably because of a severe jam). Anyway, long story short (!), I've decided it's time I got this little beast to do some work. So the rebuild starts here.

You'll be hearing more about this as time goes on, I'm sure.

Hi fellas,
I have a Dyna 2400 running prior to converting to direct drive steppers.
Presently, all the old electronics are stripped off as is the big box and
chip tray. Now we have a nice compact bench mill.
I built a PS driver box with Camtronics drivers (or xylotex) with a Dell
Latitude LS400 as the PC control and CNCPro (free now).
It seems these 2400's have gone thru various upgrades in the life of the
production. My motor drivers were in the big rear box. I also have the
adjustable leadscew nuts incased in iron.
One thing I found after stripping each axis for cleaning was the auto
oiling system was not getting to all points. I think DM was being a little
optomisistic to expect oil to get all the way to the far ends of some of the
circuits. The front X way way dry as was the Z nut. Yes, the nuts are also
fed oil! I rigged a grease gun to pump way oil, installed a zerk into the
base oiler port and pumped till I got tired and still could not oil to the Z nut.
All the lines are clear and the old rotted plastic saddle line was replaced with vinyl.
Glad to find a Dyna Myte discussion at last. There's some great info here.
More later.
Rich, Atlanta

I got my motors mounting on all three axis, now I have to wire in my C11 breakout borad from CNC4PC from my xyoltex driver board. I wanted to get the optoisolation that this board offers. Also, I want to wire my home and limit switches, but as ususal, I have no idea what I am doing. So I gotta go. Cross your fingers that I don't smoke test my boards.

Dave

Dave,
Please share some pictures of you mounting method.
The motor coupling issue is a tough one with the thrust nuts in the way on
the end of the leadscrews.
I'm trying to figure out something myself. I already have 214oz steppers
on hand.
What size are yours?
Send the pics direct if you want. I will share what I do.
Rich cmsteam(at)speedfactory.net

>woodturn;I got my motors mounting on all three axis, now I have to wire in my C11 breakout borad from CNC4PC from my xyoltex driver board. I wanted to get the optoisolation that this board offers. Also, I want to wire my home and limit switches, but as ususal, I have no idea what I am doing. So I gotta go. Cross your fingers that I don't smoke test my boards.

Dave

So, I got my three motors mounted, and running. I'll try to get some pics up one of these days. Here is the problems. My spindle will not turn on. I have X backlash of, .004" Y backlash of .002", and here is the kicker...Z backlash of .030" HOLYCOW. Me thinks I need a new leadscrew. Dumpser cnc here I come.

SPINDLE.

So why is there now power to the spindle motor??? I can't seem to access the board that rectifies and tell the spindle what to do. I don't care if the spindle is controlled through Mach. I just want the damn thing to spin!!! Anyway enough of my griping. Time for more learning.


I hope everyone's elses job is going easier than mine, but I doubt it

Dave

Dave,
Do you have a DM2400 or 2000?
On the 2400 there are adjuster screws for the backlash on every axis.
The long end of a 6 mm ball end allen wrench will reach in to the
nut area on the LEFT side of each leadscrew.
On the Z axis, the electrical cabinet will have to be removed to access it.
There are 2 scews in the cabinet that retain it. Then lift up and pull away
to remove the cabinet. It is hung on 4 other screws. Don't remove those.
Be sure to check you are getting oil to the Z nut. Mine never did.
When adjusting the backlash, turn the allen screw until the B/L just about
makes it to zero. Any more and you will bind the screw. It's best to
remove the motor assembly and turn the leadscrew by hand and feel
the B/L as you turn to and fro feeling when the slide resistance is hit.
Adjust until it is just about gone.
On the DM 2400 The nuts are self adjusting constant drag type.
Spindle motor-on the 2000 the control may be inside the head.
The 2400 control is in the cabinet.
These are 120VAC in to 90VDC out variable speed controllers.
I replaced with a Minarik or Dart modern unit.
The speed adjust pot in the head stays the same.
RichD

Sooooo.....
I think I have a 2000 or a 2200 were the anti-backlash nuts are plastic spring loaded thingies, so I have no adjustments. I'll just pull the cabinet off and see if I can preload the spring tighter. I already did that to the x and y but I'll see how the z looks.

As far as the spindle is concerned....

The 110VAC wire comes into the pot/rectifier in the head, I am not sure if I can pull it out. I am not in front of my machine now. From there four wires go into the DC shunt motor 80VDC, I believe. I am just trying to figure out what is best/cheapest way to get this thing to spin. Do you have a link as to where you got your set up and how much did it cost? I have a feeling that I will have to buy a new pot/rectifier/driver thing. I just would rather not buy a whole new power supply if I don't have to. Maybe I'll go AC and use a varabile frequency driver thing. OK, thanks for your time. Again I'll try to get some pics up.

By the way, earlier on the thread I have a pic of my lead screw without the nut spring loaded. ANd there is some other link to a guy who is doing a way better job than me on his rebuild, and I think he is using the same size stepper motors

OK

Got real work to do

Dave

Dave,
the springs are between the shoulders of the plastic nuts on the early nuts
and push them apart. The newer nuts are compressed (no spring) by a
sleeve and screw manually. So, why you have B/L is curious.
Maybe they are totally worn out?
Does you machine have an external lubricator, internal, or none?
Dyna Myte made them in all combinations.
Spindle Drive- A VFD is only for 3 ph large motors.
For your motor there are many brands of variable speed DC drives.
This will have to be placed in the rear cabinet.
Note-the early machines had the spindle drive in the head.
Later, in the cabinet and there are different versions of these.
Also these have NO torgue feedback to maintain speed under load.
The new variable speed DC drives have that and more. Well worth
getting one. I see them on ebay. Minarik or KB are good.
Sherline uses the same device and they are very good.
The pot in the head may have to be changed to a diff value.
I'm helping a friend get his running now and converting it to modern
drives & PC control.
I will be upgrading to larger steppers and timing belt drive as well.
Rich

You know your a redneck when.....

Holy heck
The reason for the Z backlash...I think they call it "endplay" the weight of the head was pulling motor coupler out of the stepper. Thrust is an issue. I am currently making a abs plastic mount that will house a brass bushing to support the botton end of the Z axis lead screw. I am growing it in a 3d printer at the local community college. My next step is to support the end of the other lead screw with some other way that Larry the Cable guy would be proud of, I know that when a load is applied to the X and Y, the same thing will happen. I know, there are jamb nuts on the end of the leadscrew at the top to prevent this kind of thing from happening....but they only work if you don't cut them off!!!!(chair)(chair) OH well gotta crack a few eggs to make an omlet.

And yes I know that I should be using thust bearings in my set up, but me being the cheap bastard that I am....I just can't do it. Wait until you hear my idea for the support of the X and Y axis. I'll take some pics so you all can laugh.

Spindle issue...

I think that my motor is good, but I have a bad speed control, so I found one on Ebay, but before I "buy now" about $30.00, I am running the idea across my friend to see if he thinks it will work.

My machine is in a million peices

This story will continue.

What's life without a puzzle


Best wishes
Dave

You're not using any kind of thrust bearings at all????? On any of your axes??? Without thrust bearings, you're depending on the axial thrust capability of the motor, which is generally poor to non-existent. As soon as you apply a cutting load to your axes, you are going to end up with massive backlash, induced by the axial movement of the screw. In addition, your motors may not want to turn any more, because the rotors are now binding against the endcaps of the motor housing.

You may not notice it with little, or no load.

I hope you weren't planning on machining tolerances better than +/- .050

A pic is worth a million words. Maybe I'll post a pic one of these days. GET R DUN.

Its been quite a while since I have posted any updates on my progress with the conversion I am doing with my Dyna 2400 mill so here is where I am at so far and a few pics.
First of all when I got the machine it had no electronics just the spindle motor. You can see the pics a few pages back in this thread.
I have a Xylotex 4 Axis setup using 425oz/in Stepper Motors. After designing the motor mounts or brackets I decided to use 6061 Aluminum and I made them manually with the machine with handles I mounted on the X and Y Axis.( I adjusted the backlash for all Axis and the torque on the thrust bearings before I used the machine) The machine worked great. Both the X and Y Axis ran very smoothly and easily by hand and it gave me a good feel for the machine and its capabilities.(alot of hand cranking to make the mounts though !!) After completing the motor mounts I designed and made the couplers that go from the steppers to the leadscrew. Next I removed my handles, mounted the motor mounts, couplers, and steppers. I originally used Turbo CNC for software but I loaded Mach 3 and set it up the other day and I am learning the software now. I do have the Machine up and running. It runs fine with both programs at reasonable speeds. I have done repeatability tests and it is accurate within about .0002-.0003 positioning trying different X, Y and Z axis moves. I have the backlash adjusted to allmost nil but not so tight that the machine doesn't move freely meaning not much drag meaning less friction meaning less wear in the long run. The thrust bearing nuts on these machines have to be tweaked just so, also.These machines have small thrust bearings, DO NOT OVERTIGHTEN them or you will be replacing them real quick I THINK because you will start getting endplay as the thrust bearings wear out from being overtightened thus slowly losing accuracy even if you have no backlash . That is only my 2 cents worth about that but someone please correct me if I am wrong here. Overall I am very happy with the machine for its size. I still have lots to do before I am done though. Lets see...resonance dampeners, limit switches, E-Stop Button, run cables through something coolant cant get at and seal everything etc etc, then I will be getting in to more electronics, etc and then I am going to design and make my 4th Axis motor mounts.
Everything takes time though. So one step at a time.

Oh ya, Good Luck with your thrust issue Woodturn ! I would also like to see some pics. Be careful not to cook your Motors or Drivers !!

Kel

Thanks kel1. Does your machine have thrust bearings on the end of the lead screws, mine does not. I'm going to try my okey way of doing things here, and I will watch my heat, if this does not work I go ahead and do it right. Your maching looks real nice. One more thing...what are you going to do with the 4th axis? rotarty table? Keep up the good work

Glad to see there are more here interested and that have these things. When I started this thread I was trying to create a place of info for these little mills. They have lots of potential and I wanted to share what I was learning. Keep up the good work guys.

Now for a status update. I have not really made any more progress as I have been saving up to get some G340 servo drives for my mill. I want to try them out and see how they do with the servo motors I have for my 2400.

I should be able to put in the order soon now and am looking forward to getting this little guy up and running.

Keep posting pics and let us know about your progress.

Alex Cole

Re: : 'One more thing...what are you going to do with the 4th axis? rotary table?'

I will eventually make a Rotory 4th Axis with a 3 jaw chuck or and a collet system so I can do 4 axis machining at different angles, etc... I will probably make it so it will run horizontally along the X Axis.

Kel

Well if all goes well I should have 2 of my drives on Wed of next week. I am starting to do the wiring design in my head for getting them in the controller. I had built a seperate controller cabnet in an effort to isolate a noice issue I was having but I have eliminated that I think. Anyhow I will try to get some pictures again soon for all of you. I will also give you some reports on how these servos seem to work with the Gecko 340 drives.

Until then

AC

So with my okey way of doing things, I got .007" of backlash on my Z axis, better than the .050" I was getting before. I need to learn some progaming and cut a part to see how it affects my work. I will be cutting mainly wood so we shall see. I might go back through the system and get my thrust issues worked out, but I would really like to learn some programing first.

Good luck on your new drives alex

Dave

Thanks kel1. Does your machine have thrust bearings on the end of the lead screws, mine does not. I'm going to try my okey way of doing things here, and I will watch my heat, if this does not work I go ahead and do it right. Your maching looks real nice. One more thing...what are you going to do with the 4th axis? rotarty table? Keep up the good work

Yes my machine does have thrust bearings on the end of the leadscrews and they are very important to have. I dont know what kind of a system you are using to compensate for thrust but dont rely on just your motors because I dont think they are designed to take much or any thrust or endplay forces to start with. Good Luck and why dont you post some pics. Maybe you have a good idea.

Kel1

Life is one big learning curve eh? So I am in the mental stages of designing a thrust surface/bearing for the outter end of the lead screw for the X and Y. I was thinking of a torrington or a angular thrust of some sort. I know pics pics pics. I need to get myself one of those fancy digital cameras one of these days. My mill is the older model a 2200 and came with no thrust on the back end of the screws, just two jamb nuts on the top which I cut off to mount the motor

What are you using to run your machine...Mach 3? Thats what I have. How about drawings, which cad package are you using?


gotta go

dave

I received 2 of my Gecko drives for my mill this week. My buddy and I got together today to work on it some and test things out. I made an aluminum mounting plate for the drives and cut cooling fins in the back. I don't have any pics of the back but here is a quick pic of my drives.


I currently have a big mess as I am testing things. Testing should pretty much be over now and I am going to start mounting and doing final wiring on the drives and breakout board.

Anyhow I should be able to order my 3rd 340 drive soon but for now I am going to use a G320 drive that I have. I figure I will put the 320 on the z for now.

Anyhow just wanted to leave an update.

AC

How fast or how many in per min and how much torque do you expect or hope to get after you have it all hooked up ?

Kel1

Well I did my initial testing at 50-55 ipm. I am planning on keeping the speed around this range due to the fact that I am not using ball screws. The lead nuts appear to be made out of some sort of plastic inside (or at least the backlash adjustment part is). I am afraid that if I try to run it much faster then I am just going to tear up the lead nuts.

In the initial tests we didn't get the motors to go as fast as we did with the drives that my buddy made. I did have the drives running the machine at 85ipm which was quite fast for how small the travel is on this machine. The Geckos seem to not want to go quite as fast. When we try to go over 60ipm we get faults. This could be tuning as I have not done much of that at this point. Right now I just want to get the mill up and running and I will work on performance once it is all together.

As for torque I think there will be plenty. The servos I am using are small but they are rated at 500ozin stall. With the size and regidity of this mill I think they are going to be a perfect match for the ability of the rest of the mechanical components.

Note that at this time I am only running the mill on a 24v power supply. The servos are rated at 30.2 volt so I am loosing some speed there. I am only getting about 79% of the motors rating so when I move up to the full 30v I figure I should be able to get 70ipm at least. Again I am not sure I want to run the components of this machine that fast.

If I do decide to go with faster/bigger setup I will switch over to ground ball screws which will maka a big difference.

The nice thing about servo is you don't hear a thing when the mill is moving...

AC

What type of collet type does this machine use and where do I buy them? Thanks everyone for posting and sharing pics/info on here, it inspires me to pull my 2400 out of storage and convert it.

Kevin

My machine uses ER16 collets You can get them most anywhere. They are available in many tolerances for runout but for most of us we don't really need to worry about getting the expensive .0002 runout collets. Regofix makes some nice ones. I found a guy on ebay that has the ER16 collets for a decent price.

I recommend that anyone who has these machines take the time to give them the once over and get them up and running. Compared to most of the small CNC machines that are available out there I feel this machine is built in a way that seperates it from the others. It has a small work envelope but is able to do some very precise detail work if setup properly. Anyhow I am going to try to get some more pics of the controller cabnet after installing the breakout board and drivers and get them posted.

You should be able to see them soon.

AC

I have some photos in this post that shows the current state of my project. As you can see I have a mess around my mill but I am in the testing and setup phase. As soon as I get things really up and running I plan on getting some video and pictures in action. Along with some project reports on how it cuts and moves.

I would like to hear and see some info from you all on how your machines are cutting and running with the stepper systems. It would be nice to see the differences between the setups. At this point I am not sure there is really going to be much difference between the two other than cost.

Anyhow Enjoy and until then

AC

I have still made no progress on my thrust issues. I have spent most of my time learning Mach 3. AC, looks awsome! 60 ipm wow! I am getting only 25 ipm with my xylotex set up. I can live with that, when I got my system I think it only went 20. Once I feel like I have made some progress with Mach 3 I will tear the thing apart and see if I can get my backlash down a bit.

Good luck to all those dynaheads.

dave

I have 1 nylon spur gear in excellent condition that I will never use and if anyone that is using THIS thread to post on and is still using the original setup is welcome to have it if they are willing to pay for the shipping costs . I got a partial list of available replacements parts for the Dyna 2400 and they want about $90.00 US from Dynamechtronics. If anybody is interested just let me know.

Here is a list of other available parts from Dyna.

driver boards for x .,y and z available .the cost of each one is : $ 250.00
Super nut
Nylon gear ( spur gear )
Driver boards x.,y ,z.
Spindle control board ( repairs only )
Distribution board ( repairs only )
Power supply ( 5 vdc and 24vdc )
Power ac filters
Emergency switch button.
Stepping motors
Leadscrews 12 mm and 14mm " lead time two to three months "
Spindle belt(Part # T0311-000530 Descritpion : Spindle belt polimax 530 )
Cost Each: $ 25.00
Formed tube ( lubrication y axis coil plastic tube )
Collet nut ( spindle )
Quick change nut ( spindle )
Axis power cables
Spindle pulley
Motor pulley
Driving ring ( spindle )

By the way if you are looking for a spindle belt locally ask for a Polimax 5M-530 or equivilent in a different brand.

Kel1

Just wanted to leave an update.

I placed my order for my last needed G340 servo drive and it should be here some time next week.

In the testing phase last weekend the computer I am using for my mill project took a dump..ok really just the onboard video did but it does not have an AGP slot so I am stuck. The older PCI video cards most likley will not work right with XP so I may have to dig up a new computer.

I'll keep you posted.

AC

I got my computer fixed last night for now!!! Yay!!! Anyhow I did my 1st real test cut last night. I cut "Missy" my wife's name into a peice of aluminum. I removed the aluminum for the video. Anyhow I made a small video. It's not fancy and it's hard to see the machine move a bit but you can see it go. There is sound in the video but you don't really hear anything..cause it's servo.

I will try to make a better video this weekend and show it cutting. THis was just the beginning. I think it will be easier to see it go with stock on the table.


Click here to watch my video (http://www.youtube.com/watch?v=YpjqSriYNcs)

AC

So I tried an idea I had to take up the thrust in the X by attaching a plate to the end of the X table and putting a couple of thrust bearings in it, and tapping the inside of the leadscrew where a bolt would extend to the plate. Even though the jamb nuts held everything OK I found the "whip" to be horrible, I am guessing that the shoulder of the jamb nut was not square to the leadscrew, or the leadscrew has a slight bend in it or both. So back to the drawing board. I got an idea that I will try to put together on Tues. I let you know how it works.

AC.....awesome....great work, Was your spindle running the video? If so I wish mine sounded like that!

Keep up the good work,

D

Let me say it now : "I LOVE MY DYNA 2400!!"

OK, enough silliness.

I have gutted one, added DeskCNC, 279 oz/in steppers and away I mill in 3 axis. Just added a converted indexer for a fourth axis this weekend, still have more hardware to mill to mount the stepper. All my mechanical backlashes are less than .001 measureable, and when I mill a hemi sphereical mold, there are no "blend" marks on the axis change points.
End rant. Anyone who wants opinions/help/adapter plate files, e - me at jetpig1@aol.com
Chow Belly,
Geo

No my spindle was not running in the video. I have been trying to work out my backlash issues now that everything is moving.

I hope to have more videos soon!

AC

Wood Turn. If you wanted I could come up with some drawings to show you the thrust bearing setup and how to impliment if you need. I forget are you using the origional gearing on the lead screw or are you using some sort of coupler to get around it?

Let me know

AC

Kel, Did you set your steppers to directly drive the lead screws ? jetpig1@aol.com

Kel, Did you set your steppers to directly drive the lead screws ? jetpig1@aol.com

Yes my leadscrews are driven directly from the steppers by couplers that I made.

Here is my 2nd video. A little bit better but at least I am cutting somthing.lol

Anyhow here I put down a piece of aluminum to cut the letters into.

Click here to watch the 2nd video (http://www.youtube.com/watch?v=LMhguTvPLDM)

AC

SORRY The link was not working but now it works.

Let me know what you think!

Alex,

I am not using the old drive gears....I did cut of the jamb nuts on the old set up to mount my stepper motors, and as a result lost all my axial thrust when the X moves in neg. numbers. So, My next step is to machine a shoulder back on the leadscrew to give myself enough space to put locking nut on the end of the shaft, thereby trapping the leadscrew between two shoulders, the one on the shaft and the locking nut. This way I can use the existing thrust bearings that came with the Dyna. Sorry if this is confusing, but again I will try to take a pic before I instal it. I hope this works!!!!

What kind of backlash are you getting?

D

Working on the backlash issue: I started by cutting a Circle, Diamond, Square test cut. Using this method allows you to see where your machine stands as far as backlash, syncing..ect. Here is the steps I took.

I 1st created a 1" square I put the X0Y0 at the lower left of the square. I then cut this square using a .125 flat endmill. To remove any possible error I did not cut with cutter comp in mach but rather I programmed with the tool diameter in mind so that I would end up with a 1" square. Here is my program.

(SQUARE TESTCUT 1)
G0G90
G0Z.5
G0X-.0625Y-.0625
G0Z.1
G1Z-.05F5.
G1X1.0625F10.
G1Y1.0625
G1X-.0625
G1Y-.0625
G1Z.1F10
G0Z.5
M30

When I ran this program initially (last week) I got 1.0003 to .9998 on the X axis for my X component on the square. For the Y axis I got .983 to .987 on the Y axis. This is a gross ammount of backlash/error. I felt my coupler on the Y axis and it appeared to move quite a bit before I saw movement of the slide. I took apart the Y axis assembly by removing the rear mounting plate for the screw and then threaded the Y axis out of the dovetail. I checked over the components and made some adjustments to the backlash screw. I put the whole assembly back together and then adjusted the backlash screw again from underneith. I also adjusted the gib screw. This seemed to tighten everything up. I ran my test again and now am getting values of 1.0001 on my Y component.

I tested the Y axis again by cutting lines at Y-.0625 which put an edge at Y0. Then I cut a line at Y1.0625 which put an edge at 1", and again at 2.0625

When measured I got right on at 1" inbetween the zero line and the 1" line. I got exactly 2" between the zero line and the 2" line.

I have digital calipers that I am measuring with so there is going to be some variation there. I have mics but I keep them at work. I may bring them home to do further work later but for now I am ok with my results.

As I understand it these machines should have a .0003 repeatablity with the origional setup.

With the Gecko drives and everything I have in this I should have a following error fault out if I deviate from commanded position by .001-.002 so as long as I can keep my backlash within this range then I am happy.

I like it, anything under .001" is great!! like I said, I tried to put a plate on the end of my X axis, but, it did not work that good, my 2200 does not come with a bearing to adjust at the end, only where the motor mounts up, so, I will try tomorrow when I can use a lathe and see if I can get some parts cut by the end of the year. Two steps foward, one back.

Keep up the good work Alex

D

Wow, it's like a real cnc machine. Huge improvement on the original Dyna controls. Good job.

D

Nice work Alex. Its nice to actually see the machines running once in a while. You can finally sit back and watch the machine do the work you.

I have been doing some testing with my steppers to see what kind of speeds I can reliabley get before losing steps. I tested each axis for top speeds and then dropped them by 20% for more reliability. The results so far after dropping the 20% are X Axis 92ipm. Y Axis 65ipm. and Z Axis 52ipm. without losing any steps using Mach 3. I would like to eliminate a bit more resonance in the higher speed range in the Y and Z Axis but for now I am happy :). My next task is mounting my limit switches. I hooked 1 switch up to test with Mach 3 utilizing my Xylotex board to access printer port pinouts VCC and ground and it works fine so now I have 6 switches to mount, wire and configure.

Here are a couple of quick videos I took. I did the engraving at 50 ipm. and the outside border was done at top speed in all Axis.

DYNA 2400 Spindle on test

http://www.youtube.com/watch?v=OioxfrZ4ihs

DYNA 2400 Spindle off test

(note: the clicking noise or vibrating noise you here with the spindle off test is actually my vise handle rattling around not resonance or anything else. I will have to do another video sometime with better lighting and no vise handle on the machine so you can here the difference.)

http://www.youtube.com/watch?v=Jm2AvjfZmKY

One step at a time.
Kel1

Nice videos Kel!

I am working on an accuracy issue now. it appears I am having an issue on my Y axis. After running a repeatability test on a 1" square my y axis is loosing position some how. It seems to be out by .075 after running around the 1" square 112 times. The odd thing is it goes .075 in the plus direction almost completly in the 1st pass and then it slowly makes it's way back into the center of the slot it has cut? Wierd. I am a little baffled at this one. I am not sure what is causing it.

I posted a msg to the Gecko drive support group on yahoo and am hoping that shortly I will get a response from Mariss. if not I plan to call him but it's hard cause I don't have the mill at work, and they are closed when I am home.

This is some of the setup hassles with servo systems but I think once I get the bugs worked out I will have a nice system going.

Kel. Your machine is moving quick...nice job. I decided to use the smaller servos on my machine do to the fact that I didn't know how long the backlash screws would last if I went too fast. Once I get this thing going I don't want to wear it out...lol Which size motors did you go with?

I think they are going to be comparable to my servos. My continous torque is like 65inoz and my stall is like 500. With the gear reduction they are 1000 rpm at the output shaft. That is at 30v. I am running at 24 so I am running below max at this point. My cuts in the videos were done at 15ipm if I recall.

Anyhow I don't have all my bugs worked out yet so it still isn't a complete deal.

Things to do list:
-setup limit switches - I have them just havnt hooked them up yet.
-setup pendent with Estop and cycle start and feed hold inputs
-setup power oiler system - I have the origional but don't have it hooked up
-Make coolant system - I don't have any parts for this yet

Kel what spindle speed were you running at when you were engraving. I was doing some in my video and I think I was moving too slow or too fast. Not sure yet. Anyhow Just curious as to the details of what you were running.

AC

Hi Alex, I am using 425oz/in steppers from Xylotex.
I dont know what my constant torque would be yet at say 10ipm. or 50 or 100 because steppers lose torque as they gain RPM (further testing required ) I do know that when running my X Axis at 90ipm and I push on the end of the X Axis to hold it in place I have to push really hard on it to make it lose steps. The machine almost moves across the bench, so as far as I am concerned my steppers have plenty of torque for the size of the machine . I will also probably back off my feed rates to 50 -60 ipm. Max to extend the life of the machine a bit and hopefully not have to worry about losing steps but I had to give it full out to see what it could do :) if you know what I mean.
I was running at 10000 rpm at 50ipm. going .025 deep with a 3/16 2 flute carbide engraving , deburring , chamfering cutter. When I cut the box around the engraving I was going 92 ipm. in the X, 62 ipm. in the Y and 52 ipm. in the Z. These are my maximum speed settings right now and my Xylotex drivers seem happy so far along with Mach 3. I am also running at 24V right now and can go to a 30V Max if I want to but I am happy with the setup the way it is FOR NOW. Its time to get my limit switches hooked up now to add the extra safety and to have the ability to Home the machine.

Cheers
Kel1

ok so a little update on my servo driver issues.

Last night I did the following tests.

I tested the machine doing the 1" square test to make sure the problem still exists. (you never know if gremlens were afoot!) Yes I still had the problem.

I moved the step and direction pins from the breakout board from the X axis(good) to the Y axis(the bad one). I still had issues with the Y axis.

This has told me that the signals from Mach and the breakout board are not the issue.

I continued to fiddle with the drive tuning (gain/dampening) and I got the servo to sound smooth while moving but I noticed that when positioning the motor would spin but when I let off the jog button it would come to a quick stop but then creep a few degrees in the direciton it was going. This had me stumped.

I talked with Gecko today and told them what was happening. They told me to send the drive to them and they will look it over and test it and make sure every thing is working good. They also told me that if they find somthing wrong they will fix/replace the drive at there expense so I will have no out of pocket expense. A+ for there support so far!

Anyhow I have 3 of the G340 drives and 1 of the G320 drives. I have had the machine setup with 2-G340 drives for the X and Y axis, and the 1-G320 drive on the Z. For now I will swap out the Y axis drive for the 3rd G340 drive and send the other in for them to test. This will allow me to continue to work on the machine and have a drive for all 3 axes. This limits my z axis speed to 25ipm but thats better than nothing.

The gecko drives so far have been really nice to work with. There documentation is complete and makes sense even to someone like me who does not have a high level of electronics knowledge.

I am some what wondering if I should have gone with larger servo motors for this conversion so that I can command more power but when I am done I think I will have a solid setup that performes at respectable levels. I am only running the motors at 24v and they are rated for 30 so I am underpowering them. In the future if funds allow I will look into getting a 30v power supply and see how performance stands at that point.

So what I am going to do is to setup my machine using
G340 - X axis - origional one that has been working fine
G340 - Y axis - new one that was for the Z but will put on Y for now
G320 - Z axis - This has been on the z until I could get my new G340 but the new G340 is going on the Y until the results get back from Gecko on the drive I send in.

Then I will do the repeatability test again and see if the new drive has any issues on the Y axis. If the problem goes away then it is defenatly an issue with the current Y axis drive and it will be sent to Gecko to investagate.

Anyhow I hope my ramblings make sense but just wanted to post an update on where I am at.

Keep the info and expecially the videos coming guys! we need to show the world what these little machines are about!

AC

ok so this morning I got a chance to swap the new drive in to the replace the questionable Y axis drive and I ran my repeatability test. I didn't have much time so I only let it run around about 20 times but the results were clear. It cut good. The slot was almost perfect. I didn't have much time to measure good but a real quick measure showed that the slot was the size it was supposed to be, so the tool had stopped creeping in the one direction, at least it appears.

I will do more testing but I need to get some more material to cut as my block currently looks like swiss cheese. This weekend I should have some time to play around with it and get things dialed in. I will send the drive back to gecko on monday if I still feel like that was the issue.


Progress is still being made!

AC
(It doesn't matter how far we go back as long as we keep moving forward!)

Yesterday I finished machining the y and z axis on my leadscrews, so all my screws are done ready to be reinstalled, the only problem is that work is getting in the way. Question for Kel and AC, what material are you lead nuts made from? Boss is coming, gotta go
d

lol well remember that we all need to keep our day job at this point. but anyhow, as I understand it the backlash adjustments on mine are made of some synthedic nylon or somthing. This is why I worry about running the speeds too quick. To be honest I have not taken the time to pull one apart to find out as it is housed in a cast block.

I figured I would get my machine moving and test things out and see if I need to do teardown for repairs. I have been thinking about the screw issue a lot though and I think if I ever have an issue that I will replace them with ground screws. I am also considering designing a new spindle head for the mill. I think this machine could have large performance increase just by going with a stiffer head setup.

Woodturn, Get us some pics of your progress! I'm sure we would all like to see.

AC

Yesterday I finished machining the y and z axis on my leadscrews, so all my screws are done ready to be reinstalled, the only problem is that work is getting in the way. Question for Kel and AC, what material are you lead nuts made from? Boss is coming, gotta go
d


I am not exactly sure what material the 'Supernut' (as Dyna calls it) is made out of but it is 2 seperate parts with an O ring in middle of them according to my drawings. I really dont think they are made of 'nylon' on the 2400, I think they are some type of steel alloy or maybe babbit bronze internally but I am not positive. You would have to contact Dyna and ask them. As far as any nylon that is used I do know that there is a M5 -6 set screw that tightens down onto a nylon pad in the nut assembly that holds your nut adjusting screw in place. I hope this makes some sense. I would post a pic of my drawing but I dont know if Dyna would appreciate it or not. I guess I could contact them and ask but.... In any case I haven't had to take mine apart yet since my machine was only used for maybe 25 to 50 hours when I got it so its only just broken in. I only had to do minor adjustments to the Gibs , Nuts, and the thrust bearings to achieve very good accuracy and repeatability in all Axis directions.

Kel1

Updated Video engraving at 50 ipm.

http://www.youtube.com/watch?v=5StvhXSJWRw

Kel1

Today I made my first test cut, a 3" circular pocket using the wizards on the Mach 3 software, and things are good. I did not put an indicator on each on the axis, but the pocket came out +or- .001" according to my harbor freight dial calipers. So, on to the next stage, homing switches, I just hope I know where I put them!

dave

Time for another update! Sorry for the delay guys but I have been busy.

I received and hooked up my 3 G240 drives and noticed that my Y axis had some positining issues. It was loosing position after just several passes on the part. I talked with Gecko drives about the issues and they told me to send in the drive. I did this and they proptly sent the drive back to me after replacing some bad ICs on the board. They were great about it.

When the drive returned I put it on the Z axis and started cutting some test parts. It seemed that everything has been running accurate.

Then the other night I was doing some engraving where there were lots of Z repositions and I noticed that the Z axis kept getting higher until it was not cutting anymore? I was not sure what was going on there. The Z axis has the repaired drive on it so I am not sure if the drive is a fault again. I started doing some reading and I think I may have found some of my issues.

I am using the CNC4pc C11 breakout board. This is a great board and seems to work well but I found that the board has opto isolators on all pins. The gecko drives also have opto isolators on them and from what I have been reading this can cause lost steps. To try to remedy this I have on order a C1G breakout board from CNC4PC. This board has opto isolators on all pins except for the pins going to the drives. At this point I feel that this might fix the issue of my Z axis drifting.

When my Y axis was exibiting problems it would drift off in 1 direction over several passes and then it would drift back in the other direction. So it was not just loosing steps in 1 direction. The Z axis seems to be loosing steps in just 1 direction and it appears that it's motion is moving up. You would think it would loose steps when moving up and this would make it start going deeper and deeper but I am actually loosing steps going down. This is why I think it may be caused by the breakout board.

When the board gets here I will test it out and let you know how it does. I have some parts I have cut on the mill (not Z critical) that I will try to get pics of and post.

I have to run for now but wanted to post and update and wish everyone a happy and safe holiday!

PS keep posting about your progress and parts you are making

AC

I am in the process of making a clamp for a my mill. It came with a nice fixture plate made by the Jr. college here. It has a 1/4 20 hole every 1 in. once I get that made I'll cut some engravings and post my findings.

D

I am new to this forum so this maybe in the wrong place for this question. I have a Dyna mill and this thread is great info. What I would like to know is if anyone knows what kind of signals the Dyna axis cards require. Rather than converting all of the electronics on this mill, I had idea that maybe I could install a brakeout board and then wire it to each of the axis cards so that I can use my computer with Mach 3 to run this mill. If anyone has tried this I would like info if it would work. don't like to let smoke out my computer or the mill.

I had the same I idea, but could not figure it out, but maybe you can. I think that motors on this machine is under power, new motors are nice

I am not sure on that one oldkitster. You can contact Dyna and buy the wiring diagrams for the driver cards. They will probly charge you $50 or so dollars for it. This would be the safest way to keep from smoking somthing.

AC

Kitster

I am starting to do the same as you propose. I called Dyna and asked if they could tel me the pinouts for the drives. They said they can't tell me because they still service these machines and so the pinouts are proprietary still. He told me that when the machine becomes obsolete and they no longer service it, they will release the schematics. He did say that they are step/dir type drives but would not comment further. I will be digging into it in the next few weeks.

Matt

Kitster I am starting to do the same as you propose. I called Dyna and asked if they could tel me the pinouts for the drives. They said they can't tell me because they still service these machines and so the pinouts are proprietary still. He told me that when the machine becomes obsolete and they no longer service it, they will release the schematics. He did say that they are step/dir type drives but would not comment further. I will be digging into it in the next few weeks.

Matt


I reverse engineered out all the pinouts that you require. (posted below) I was attempting to develop a Plug & Play PC interface, but i have just about
given up on it. Posted is the results of a LOT of work on my part during the development, that i'm now freely giving out to everybody.


I spent a lot of hours experimenting, and i can not seem to make the original Dyna stwpper drivers work properly. I was trying to develop my interface to work with any software, however, software/hardware limitations seem to prevent this.

The short answer is: Yes, the dyna drives are step/direction drives, however, they do not seem to be able to use the short-duration "pulses" of PC-based CNC controller software. The original Dyna controller feeds them a variable-frequency square wave signal into the "step" input, NOT a relatively short pulse, and a variable delay like modern stepper drives seem to be able to use.

The Dyna drives are full-step drives, but they do not seem to hold the phases "on". It seems like they just turn them on momentarily for long enough to move the motor, and then turn them back off again. This belief is compounded by the spec sheet of the motors, and current rating of the 24v power supply, which is not really large enough to handle all the motors at once. My latest belief is that perhaps the "on-time" of each coil is related to the pulsewidth. I can't check this, because I do not have a real oscilloscope, just a jerry-rigged device that plugs into my PC sound card that works with 5v only. Perhaps someone with an oscilloscope can check this out.


Using various software, i have had mixed results. Nothing acceptable yet though. The best luck i have had is with TurboCNC, which is a DOS-based software. Personally, i think this controller is fine, however, as i said, i was trying to develop a product that would work with all PC-based controller software. TurboCNC works using a pulsewidth of 50ms (TurboCNC documentation says this is in microseconds)

EMC2 and Mach3 can't seem to get pulsewidths this long, and seem to drop steps during the accel/decel portions of the move. EMC2 does not seem to have adjustable pulsewidth (maybe i just don't know how to set it properly) according to their documentation "step signals are turned on during one cycle, and turned off the following cycle" I can not seem to get the speed slow enough. mach3's "motor tuning" screen says step pulse range is 1-5 microseconds, however, it accepts a value up to 25, which unfortunately, is still not quite slow enough.


Now, the pinout that you have all been waiting for.

The stepper diver cards: these have 2 connectors on one side, a 2-pin connector, and a 6-pin connector. I'll start at the 2-pin connector on top (for those who have their drives mounted in the cabinet) farthest away from the 47mf electrolytic capacitor and go in-order.

1: Ground
2: "active axis" (explanation below)

1: Limit switch output (explanation below)
2: Direction input
3: Step input
4: +5 logic supply to drive
5: Ground
6: +24v motor power to drive

Now, for the 2 explanations.
"active axis" (my name) means, that during the initilization cycle, this pin is used by the controller to ask if there is an axis present. It's really only important for the optional U-axis, which can be present sometimes, and sometimes not. I didn't write down exactly how the communication is done, because for my purposes this communication wasn't needed.

The limit switch output is normally held low, but when the switch makes contact, this pin goes high. This is buffered by the drive, because the switch operates differently than this. however, it is a very convienent behavior for connection to a PC.



Now, i'll tell everybody the real secret of easy connection to this machine. Remove the "machine distribution board" from the left-hand side of the machine (looking from rear) Notice the 2 large chips in sockets (INS8243N) The lower one controls everything. You can remove it, and replace it with a IDC DIP header, and run the ribbon cable to whatever interface you want to make. Everything is available at this socket, and are logic-level inputs/outputs at low current.

The pinout of the DIP socket is as follows. (using standard chip pinout notation, down one side, and up the other)

1: U-step
2: U-dir
3: Z-dir
4: Y-dir
5: X-dir
6-11 are used for communication with the other 8243 chip, which interfaces with the controller
12: Gnd


13: Buzzer out
14: tool probe in
15: spindle on
16: Not connected
17: X-limit
18: Y-limit
19: Z-limit
20: U-limit
21: X-step
22: Y-step
23: Z-step
24: +5v

Oh, and by the way. Yes, the original dyna motors are kind of on the small-side power-wise, but they do run through a 10x1 reduction gearing system, which means they can produce plenty of torque on the screw for any reasonable cut you might want to ask of this machine. The 10x1 reduction means that the max table speed is kind of low, but hey, it's a pretty small machine, and i don't think most of us are using these as production machines anyway, so personally, i think the speed is fine as well.

Thanks a lot Mike!

That will help save some time, however it may be bad news with the step pulse width as I was planning for a plug and play with mach. I guess I will play around with it a bit and maybe upgrade if necessary.

We will see what I can come up with.

Matt

I'm not 100% sure exactly why the drives don't step properly, i'm just giving everybody the results of my testing. I haven't figured it out completely, it's just a hypothesis, based on the fact that the dyna controller DOES output a square wave, and the drives don't seem to work reliably with anything less than 50ms pulsewidth.

If you do figure something out, please let me know.

If anybody has the hardware to read the program off the EPROM on each drive board, that knowledge might help a lot to understanding the problem. Maybe some new EPROM software would fix the problem. If someone has a burner that can read/write an 8748H (40 pin old-style EPROM) let me know.

Maybe someone who is good with software can make a mod to EMC2 to output square waves as an option.

Ok, so posting this prompted me to do a little more experimenting.

Looks like the dyna drives use a fixed "power-save" period of approx .08 - .11 seconds after the last pulse, where they shutdown the motor coils. This is in the EPROM program (actually, it's a single-chip microcontroller with EPROM memory) This means it has nothing to do with the step pulse width.

Using TurboCNC, i messed with pulsewidths and made some measurements using my hack-oscilloscope (see prior post). 25 Microseconds seems to indeed miss steps. It didn't seem to matter what the jog speed was, it dropped random steps.

The missed steps are measured directly from the microcontroller output, before the power even gets to the motor power drivers. i'd say about 1 in 1000 steps are missed. Not a lot, but since stepper systems have no feedback loops ANY missed steps is a problem.

I didn't try any times in-betwe