Hi all,

I'm a student in philadelphia, about to enter my senior year of college.
Our school shop has a vertical mill and a small roland cnc machine. The short of it is, I won't have the school shop forever, and there are 30 new sophmores entering my program next fall. You can bet that sharing the shop,
and trying to do any kind of precise work on an abused "Mighty Comet" mill
will be next to impossible. Thus, in january, I started thinking about making my own cnc mill. Since then I've been scanning the net, reading, and collecting anything that might contribute to this project. I Think I finally have enough parts to get this thing going.

I pretty much have one goal:
>>>>> I'm aiming to be able to cut aluminum... well.
My sub goals include making my machine faster and more powerful
than the roland desktop job. In addition, I"m thinking about making this all metric.

I have a bunch of material already to start with, but from here on out,
I think I could use the advice of any who are interested.

here's some stuff I already have:
-taig er collet spindle and upgraded motor (1000-10000rpm, 1/4hp)
-30" heavy duty iko linear slides (2 rails, 4 cars)
-21" iko lwl linear slides(2 rails, 4 cars)
-an ebayed thk assembly w/ ball screw. 6" of travel ( I'd like to use this for my z axis)
-various amounts and sizes of aluminum plate with thicknesses between
.75" and .125"
-a bit of heavy aluminum u channel
-a bit of that 80/20 extrusion.
- perhaps 25' of this weird i beam extrusion (its not what you might think, i'll post a picture. I think it might not be heavy duty enough, so this may be for making a cabinet or something...)


I'll post some pics of what i've got, in the next day or so. I'll also be posting
some sketches of some of my ideas about the design(I can model, but i'm no where near needing dimensioned shop drawings yet...)
stay tuned!
cheers!

How big of work area are you thinking of? How well do you want to be able to cut aluminum? How much/how fast?

Just few question i'm wondering about :)

Also what electronics are you thinking of? Servos? Steppers?

well, I'm hoping with the amount of rail I've got, that I can get an envelope of about 23"X18"X6," also I'm pretty sure I'm going with steppers. From what i can tell, the primary factor in how fast feed rates get is the power of the stepper motors being used. My big concern now is to have a really rock solid machine. I'll sort out the how far i'm going to go for steppers when I know exactly what they going to have to push around.For the time being, I would like this machine to cut faster than our roland machine at school. (I don't have the figures on me but i'll post them soon, I think it will be an easy goal...)

the feed rate of the roland descktop cnc that i want to beat is
1.2 m/min.

here is the general design of the machine, I still need to detail it tho.

I would switch the Z-Axis to the otherside of the Y-Axis to gain more workable area on the table top.

Joe

I originally wanted to offset the spindle with the table as you suggest, by pushing the spindle back (I have seen many routers using this configuration)
My taig spindle's motor is hanging off the side of the spindle. If I flip the z around, the motor will bump into the gussets and severely limit the travel of the y axis. I 'm going to offset the table itself and the bottom most rails to compensate for the z axis' overhang. I think this will achieve the same goal.
I'll try and upload some orthgraphics to help with the visualization.

this is not orthographic, but it shows what i'm talking about by shifting the table one way and the rails the other. now the spindle has access to all reaches of the table.

I feel bad that I haven't been keeping this page up. Since school has started I have only been able to work Saturdays on the cnc project. Its been developing slowly but surely.

First off, I got some more parts.

1> gecko had a nice sale at the end of August so I took advantage and picked up 3 of their basic stepper drivers. I also picked up some solid copper heatsinks to match at a garage sale! I'm hoping those will will provide enough power to get things going.

second, I've made a number of changes to the design of the machine.
I've reduced the cutting envelope in both the x and z axis in the hopes of increasing rigidity. Also, the old design called for the spindle to be cantilevered out on this long plate. I figure that will be a big source of vibration so I deep sixed it. Now the spindle rides right over the linear bearing blocks.

Finally, I've been analyzing the design in terms of inertia and gravity. I've moved the I've tried to put the center of gravity of the zy assembly right in the middle of the x cars so their isn't torque on the rails from just the assembly wanting to fall over all the time. Also, Initially, I was going to use the taig 1/4 continuous duty motor to drive the spindle. that thing is just too heavy. I'll use it for something else (maybe a small cnc lathe? ) I'm hoping I can find a dc motor that is sufficiently small enough to not throw off the balance of the machine but still put out the power. This is an area that I actually need help with. How does one determine the appropriate torque and rpm for a spindle? I've seen numerous equations but I always get mixed up with the differences between feed rate and surface feet/ min and the like. I have redesigned the plate that the spindle attaches to with a matrix of tapped holes. hopefully this will provide enough versatility to accommodate putting off the motor decision till after the machine is made.

here is the first finished part. It is a riser block to accommodate the size of the cnc dumpster leadnut

I will also upload a pic of the updated machine design

ah

Today i busted out the Z platform. I'm attaching pics of the plate plus the spindle and the old motor.

all of the extra holes are for versatility. most of them still need tapping (10-32) Like I said before, I haven't found the motor that I will use yet, but hopefully I can fit it in some where. As far as figuring out the specs of the motor I need, I have a handle now on the equations for finding rpm based off of cutting speed and tool diameter, but I don't know how to relate those to torque/ horse power requirements.

Good work. What is that part you are using for the spindle? And where did you get it?

OOPs Never mind I found where you said what the spindle was, how much did you pay for it?

I ordered the psindle directly from taig in arizona, I think the spindle cost
about 80 bucks (I got the ercollet upgrade version)

Nice looking machine and super machine work. Keep the pictures comming.

Could not find the Taig ER Collet spindle out of Arizona. Could you post the link?

Thanks

if i'm not mistaken,
the taig manufacturing facility is in Arizona.
When I ordered the spindle and motor, I called
the taig factory directly:

TAIG Tools, 12419 E. Nightingale Lane, Chandler AZ 85286.
email - sales@TaigTools.com or Phone - 480.895.6978

They were happy enough to sell me just the parts of the
mill that I wanted.

OK, I found them thanks for the quick reply.

for those who are following this thread, I'm trying to update it every saturday since that is the only day I can work on the project. This weekend might be a little different since its thanksgiving weekend. I'm going to bring some metal home with me and hopefully I'll get to machine it at my father's lab. Anyway, the update might come on sunday.

hi all,

(For the American CNCers) i hope everyone had a good holiday. I got sick with a cold and I only managed to do the hole drilling on the next piece. here is a pic of the progress.

the picture is of the base plate for the z axis. the rails and the spindle mounting plate will be bolted onto this plate once it is finished. i still need to mill slots for the rails to sit in .

Does anyone have any advice on how to machine on a plate of metal without using a vise and without extending the quill? I have found that the quill lock is extremely unreliable on the mill i'm using. the spindle is too high to machine plate material located directly on the bed. using a vise and parallels throws the tram out by about .01 across 12 inches, but the workpiece is accessible without the use of the quill. Using the bed, the tram will be excellent, but I will have to deal with the quill throwing off Z depths. this is critical because the thk rails need to be coplanar. any suggestions on what to do?

Put a peice of bar stock or something similar between the quill gauge and boss sticking out of head then run adjustable gauge stop from bottom to lock quill in place.

I just picked up a spindle and motor from Taig for my router. It's a nice size (60" x 37" x 12") but I'm starting to consider the weight capacity now as well....:confused:.

Thanks 64dodge, I'll give that a try. that sounds too simple to not work!

Also to MRM,

See what I'm saying about the weight of that motor? there was this guy I found on
the cartertools taig website who was using this tiny swiss made dc motor to run his taig lathe. I think a similar setup might be possible but for a mill. here is the link

>>>http://www.mechanicalphilosopher.com/picture.html<<<
look under: "Keith Shaw's Lathe and Mill Projects" he talks some about it.

I"m afraid progress will have to halt for the next two weeks. its finals now at school and on Monday I will be entering the grinder. I intend on finishing the project between new years and the end of January, so expect action soon.

I'm on break now, and I'm making the big push to get this done before
January 17th or so. "m almost done with the Z assembly. all that is left is to make the motor mount and to install the lead nut and lead screw.

I decided to get a 1/2-10 2 start stainless acme lead screw.
With that finally decided I can start to think about cutting speeds

Does anyone have any recommendations for stepper motors in respect to
cutting speed/force? I intend on using this machine (almost exclusively) for cutting aluminum and plastic. I have gecko drives so That should give some indication of the range of motors I can handle but I really don't know where to start with this selection process.

pics coming up

the first pic is of the z plate. note the new bearing blocks. They have ss abec 5 bearings in the them. I hope that holds up!

the second pic shows the underside of the Z car. The two pillars receive the lead nut and allow the screw to pass through.

the 3rd shows my bearing puller. the bearings fits so tight in their slots that I needed to bust this thing out to remove them.

4th is a pic of the z plate with a bearing seated in it. no problems with misalignment here!

I have more done.

this is the plate that the y axis *(pictured above) connects to the x axis with. triangular plates keeping the whole mess square will be coming next.

Nice looking stuff! Having access to the right tools has it's advantages for sure. You will have a nice looking / working machine when your done

here is what I have so far.
All there is left to do is adding the x axis screw and bearing blocks
and making the machine bed.

also has anyone using linear bearings (like thk iko etc...) found that
when mic'd, the rails were not equadistant even though they move smoothly
and evenly? I have one of my x axis (long axis) as a master (locked in place by a straight slot) and the other is slaved to it (progressively tightened down using the master as a guide.) both rails are tight down and the movement is even and smooth along the length but they are actually out by about .005 does any one else find this strange? There is no binding or anything like that, but I'm still mystified. originally, I had milled precise slots for both rails and they were parallel to .001 over 28 inches with no room for adjustment. When I moved the aluminum bridge (spanning both sets of bearings ) the motion was loose at one end and tight at the other!!! I went back and milled out more room around one of the rails so i could use the master slave method of alignment, which, as I said gave smooth consistent motion but the rails were way out.

also these big stand offs for the y axis are probably my favorite aspect of this machine.

Looking good!

thanks!

I hope this thing works!
I'm already thinking about making another!! is this normal?

now i just need too buy stepper motors, a power power supply for the steppers, a dc spindle motor, and a power supply for that.

Also, does anyone no of a free CAM program that outputs gcode?

Yes, CamBam. 2.5D with some 3D features being added. Beta development stage presently.

Check it out at http://www.brusselsprout.org/CAMBAM/

CarveOne

things are on hold now while I gather up the electrical parts for
the machine. I'll post pics of all the gear once I get it.

taig spindle drawing

I'm already thinking about making another!! is this normal?

:) Yes, it's called routeritis or millitis.....have a friend that tells his wife he is "going to play routers" which means he's going to tinker with his latest machine build/tweek.

Hi all,

time for an update. I got all of the electronics going a couple of weeks ago and I finally have a computer running mach 3. unfortunately, There is a problem and I'm trying to hunt down the cause. here is a picture of my electronics setup.

My motors aren't moving the distances I tell them to move. In addition the error is not repeatable. I have tried calculating the steps/" and I have used the calibration function. the motors make this resonant sound when operation (at all but the lowest speeds.) In addition, the pulses are erratic and change frequency depending on which direction the motors turn. I'm going to hook up another motor I have as a test to see if the problem is with the motors I got. I am also going to try and watch the pulses with an led (out of the breakout board and in between the drives and motors) to see if the signal is getting screwed up.

any suggestions? Are my drives placed too closely to the power supply?

OK,

so that previous issue was due to my modern PC's weak output from the parallel port. I needed a powered Breakout board to bring the signals up to 5v.
I got one from CNC4PC and now everything is stepping consistently.

Now there is a new problem, two of my gecko drives are working fine, but the last one trips the 5amp fuse when I push the motor past about 30 IPM. I checked the wiring, its identical to the wiring of the working drives. Any suggestions?

Also, for those who asked about using the taig continuous duty spindle motor and whether it is too heavy or not... I have been using it and it is heavy enough to back drive (downwards) my 2 start 5tpi leadscrew w. delrin nut. that said, under power the z axis is fine, the motors handle the weight easily.
I will eventually need to counter weight the Z car if I want to keep my Z settings after power down.

Any updates?

I am in france right now, walking from le puy to santiago in spain. that said I won;t be workin on the machine since it is back in les etats unis. I did send that last drive off to gecko and they fixed it and sent it back. I won't be able to set everything up for keeps until september when I get back. to all those who are following this thread, check back in early septmber for when the chips start flying,