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BobLWeiss
04-02-2007, 12:56 PM
I decided to jump in and build Joe's model because the machine I have now (which was based on LionClaw's model) was cut out by hand using my wood shop tools but its not 100% lined up right and I can't get it move faster than 40ipm on any axis except Z. :tired:

I used 1/2"-10tpi Acme threaded rod from Enco on all axis and EMT pipe for the rails. I am basically happy with it except for the speed. I tried re-aligning the rods once or twice and its not getting much better so I decided to use that machine to cut out the parts for Joe's design and then move all the parts over to this one.

I have a question if someone could help me out, I have access to Solidworks 2007 and converted all of Joe's DWG files to DXF format then used ACE to convert those to GCode. What diameter bit should I use to cut the 1/2" MDF with? Also in ACE it says Default Z Offset -0.750000 and you can change this value. What is this for? And is the Default Max/Z Pass value the amount of depth it will plunge the bit for each pass? It has it at 0.25 as the default, is this good enough or too much you think?

Thanks for the help and I will post pictures as I start building,

Bob

bp092
04-02-2007, 02:01 PM
I decided to jump in and build Joe's model because the machine I have now (which was based on LionClaw's model) was cut out by hand using my wood shop tools but its not 100% lined up right and I can't get it move faster than 40ipm on any axis except Z. :tired:

I used 1/2"-10tpi Acme threaded rod from Enco on all axis and EMT pipe for the rails. I am basically happy with it except for the speed. I tried re-aligning the rods once or twice and its not getting much better so I decided to use that machine to cut out the parts for Joe's design and then move all the parts over to this one.

I have a question if someone could help me out, I have access to Solidworks 2007 and converted all of Joe's DWG files to DXF format then used ACE to convert those to GCode. What diameter bit should I use to cut the 1/2" MDF with? Also in ACE it says Default Z Offset -0.750000 and you can change this value. What is this for? And is the Default Max/Z Pass value the amount of depth it will plunge the bit for each pass? It has it at 0.25 as the default, is this good enough or too much you think?

Thanks for the help and I will post pictures as I start building,

Bob

I believe joe will be able to answer some of the questions better but I will do my best. I think that the z offset was -3/4" because you have to set (or should) a safe z for the machine to travel at and rapid rate at. This is a height in which the tool bit can safely clear any obstructions on the cutting table. IE: screws, clamps, etc. 1/4" stepdown is a bit much for a small machine, I like to go with 1/8" - 3/16" max on joe's 06 machine for best results and cut at around 60 IPM for MDF and solids. If you're generating your own toolpaths you can use any size bit you want. I believe joe cuts those parts with a 1/4" upspiral bit to maximize those tight spots in what he can cut. Lastly, welcome aboard!

Have fun, any questions, ask; there are a lot of us here running the machine!:)

ger21
04-02-2007, 02:13 PM
Z offset in ACE is the depth of cut, and needs to be a negative number, which assumes the top of your part is Z=0. What you're calling the safe Z height is called the release plane in ACE, and can be found by double clicking the layer in the priority window.

BobLWeiss
04-02-2007, 02:19 PM
Thanks for the help, I just got done converting all of the parts for the Z Carriage and used .125 for the Default Max Z/Pass number and -0.50 for the Default Z Offset. This is assuming I am cutting 1/2" MDF. Does this sound right to you guys? I am going to test cut one of the parts tonight and if all goes well continue on with the rest.

Bob

bp092
04-02-2007, 03:36 PM
1/8th inch pass on a 1/2" thick mdf sounds okay, and -.50 would be 1/2" mdf yes. Mdf that I've seen is usually right on, plywoods are all over the place sometimes between units and even sheets within the units. That's why its always nice to cut through the material into your spoilboard a tad (even a few thousands) to ensure you are making it through your material. But the mdf shouldn't be a problem. Sorry for the confusion on the z-, wasn't familiar with ace!

BobLWeiss
04-19-2007, 10:19 AM
I see that most people are using the Hitachi router as a spindle for their builds and I was wondering if you can change the brushes on this motor if and when they finally burn up?

I was using an older Sears router for my spindle until I ran a job that flattened my table top and just as it reached the end it burn up and had to be replaced. There was no way to replace the brushes nor get to them easily. I am using a Ryobi router now but want to upgrade to something that will last a long time or be able to be repaired easily.

Has anyone thought of using a motor and making their own spindle? I just read a thread on here somewhere about the same thing but it I am not sure where to get the body for the spindle and how to handle the collet issue. I like the idea of the router because you can easily use different diameter shanks with it.

Bob

fade2black
04-19-2007, 10:36 AM
Not sure about replacing the brushes, but I have been abusing a Hitachi M12V in my router table for over 3 years now and it hasn't missed a beat. It probably runs a total of 2-3 hours almost every day too. Best darn router I ever bought and I have a couple of Porter-Cable's as well, but the Hitachi's are one heck of a good router for the price.

joecnc2006
04-19-2007, 11:12 AM
I have used the Hitachi router on my machine, going on 1.5 yr and never had a problem, have not even replaced the bushings with the spare ones provided in box yet.

Joe

BobLWeiss
04-19-2007, 11:16 AM
Glad to hear it is working that good.. I guess I am going to Lowes tonight! :)

BobLWeiss
05-21-2007, 10:43 AM
I finally got all the parts cut out using my existing machine and began assembling last weekend. The longest part of this build is waiting for paint to dry! :rolleyes:

These are some of the parts after painting...

Bob

BobLWeiss
05-21-2007, 10:52 AM
I decided to order 1/2"x10 (5 start) for the x axis and 1/2"x8 (2 start) for the y. The z I am going to leave the 1/2"x10 (1 start) as is since the speed is adequate already. I am anxious to see what kind of rapids I get with the 5 start screw on x.. my calculations figure I should see around 300+ ipm on it.

Bob

joecnc2006
05-21-2007, 12:34 PM
Looks good, with the 1/2-8 two start i get over 200ipm rapids.

joe

BobLWeiss
05-22-2007, 04:01 PM
Here are the pictures of my X axis construction and the Z & Y axis put together. I just got the 1/2"x8 rod today but still waiting on the dumpster nuts to arrive so I can mount the motors.

The 1/2"x10 (5 start) rod won't be in until next Tuesday according to UPS so I can't shut down my other machine and move the motors and drivers over until then.

Bob

ClaudioG
05-22-2007, 06:48 PM
Looking great Bob.

The two tone colour scheme should look pretty slick, and happens to be our national colours that our sporting teams and others wear. Looks better on your machine than their uniforms though I must say.

By the way, given the line up problems you had with your previous build, were you able to get the accuracy needed when cuttings Joes parts? I assume some cuts would be more critical than others in order to get an accurate Joes on completion.

Also, I remember seeing a link that I think Joe posted somewhere which explains the different types of ACME thread (2 start, 5 start, 8 TPI, 10 TPI, etc). Anyone seen this or can they explain the differences?

What was the reason for you choosing 5 start ACME? Would the faster speed give less accuracy?

Cheers

Claudio

ClaudioG
05-23-2007, 01:54 AM
Also, I remember seeing a link that I think Joe posted somewhere which explains the different types of ACME thread (2 start, 5 start, 8 TPI, 10 TPI, etc). Anyone seen this or can they explain the differences?


Never mind. I found this info on the McMaster Carr web site;

http://www.mcmaster.com/nav/enter.asp?pagenum=1051

Claudio

ccsparky
05-23-2007, 08:14 AM
Here are the pictures of my X axis construction and the Z & Y axis put together. I just got the 1/2"x8 rod today but still waiting on the dumpster nuts to arrive so I can mount the motors.

The 1/2"x10 (5 start) rod won't be in until next Tuesday according to UPS so I can't shut down my other machine and move the motors and drivers over until then.

Bob

Looking good Bob! Your color scheme turned out very nice! Joe's daughter has probably picked your build as her favorite :)

Keep up the good work, look forward to seeing your machine in action!

Bob

BobLWeiss
05-23-2007, 08:56 AM
Looking great Bob.

The two tone colour scheme should look pretty slick, and happens to be our national colours that our sporting teams and others wear. Looks better on your machine than their uniforms though I must say.

By the way, given the line up problems you had with your previous build, were you able to get the accuracy needed when cuttings Joes parts? I assume some cuts would be more critical than others in order to get an accurate Joes on completion.

Also, I remember seeing a link that I think Joe posted somewhere which explains the different types of ACME thread (2 start, 5 start, 8 TPI, 10 TPI, etc). Anyone seen this or can they explain the differences?

What was the reason for you choosing 5 start ACME? Would the faster speed give less accuracy?

Cheers

Claudio


I was able to get my first machine to cut out the parts accurately by going 20ipm max speed. It took a LONG time to cut out the parts but at least they are done now.

As for the 5 start rod, I choose it for speed. If my calculations are right I will get (200 x 10 x 2 = 4000) steps per inch on it and that comes out to .00025 inches per step precision. I do mostly wood work type stuff and soft metal work and that is plenty good for me. Anything more than that (i.e. 2 starts or 1 start rods) would just be overkill.

The speed should be minumim 5 times what I am getting now (100 ipm) but since a well built Joe machine can get you 80ipm or so using a 1 start 10 turn rod then 5 starts should get me 400 ipm rapids. That might be way too fast but who knows..

I can't wait to see it move..

Bob

BobLWeiss
05-24-2007, 04:07 PM
I just finished cutting the 1/2"x8 rod to size and filed the ends down so that the bearings would fit. I ordered shaft collars from MSC instead of using DumpsterCNC's threaded ones to hold the bearings in place. They lock down using a set screw but not on the rod itself. It tighten's by clamping the rod all the way around and the set screw is more of a tightening screw like on the router mount.

I also mounted DumpsterCNC's anti-backlash nut using Joe's new mounts (nice and tight fit with the flanges!). The best thing about building this machine using pre-cut parts from plans is that everything lines up PERFECTLY! My biggest problem last time was misalignment of the shafts which caused lost steps at high speed. That machine I cut the parts out using standard woodworking tools. Nothing compares to CNC cut parts. Its a joy to work with. Even the 1/4" threaded rods for the top of the Y axis torsion box went in without having to align each hole with the rod. I just pushed it through and it came out the other side easily.

I am still waiting on the 1/2"x10 5 start rod to come in for the X axis and that is not until next week sometime.

I won a rotary axis on ebay last week (rotary axis (http://cgi.ebay.com/NEW-5-HIGH-TORQUE-CNC-TYPE-ROTARY-TABLE-W-DC-MOTOR_W0QQitemZ150125574061QQihZ005QQcategoryZ41943QQssPageNameZWDVWQQrdZ1QQcmdZViewItem)) which is due tomorrow. I am going to modify the X torsion box to fit it. I have a DC servo controller ready to go and just need an encoder for the motor. This will be cool is it works like I hope. I will then have a C axis to play with. Doing ornate spindles will be nice.

Bob

joecnc2006
05-24-2007, 04:59 PM
Glad to see everything comming together nicely for you.

Look forward to seeing the finished machine and maybe compare its good and bad points to your previous machine, side by side.

Joe

BobLWeiss
05-24-2007, 05:25 PM
Here are some more pics...

Bob

BobLWeiss
05-24-2007, 10:17 PM
More progress pictures...

Bob

BobLWeiss
05-29-2007, 09:13 AM
I got the X axis rod on Friday so I was able to work on the machine over the long weekend. I am almost finished and the only things left to do is to sand the X axis pipes (that is the worst part of this entire build), assemble X axis, and attach threaded rod to X.

I finished the Y and Z axis and tested them out with Mach 3. The Z axis is the same as before except now with U-bolts and bearings holding it on. The threaded rod is 1/2" x 10 one start but it seems to glide alot better. I am able to move it at 80 ipm without problems.

The Y axis was going to be my big test since I was only able to cut at 20 ipm before using the 1/2"x10 one start rod. It would stall my motors out when I tried pushing it past 40 ipm but if I tried cutting at that speed or anything above 20 it would lose steps sometimes which made it unreliable. My motors are Kelings 400+ oz in size 23.

With the Y axis now using 1/2" x 8 two start rod is glides nicely at 100 ipm and I could cut at 80 ipm without worry. THere is a little wobble in the rod when the carriage is at the far end of travel which causes stalling at higher speeds for the last 3 inches or so. I am trying to figure out something to eliminate the wobble.

Here are some more pictures..

Bob

joecnc2006
05-29-2007, 01:12 PM
The machine is looking good, On the whipping of the leadscrews, what i did was make anti-whip block and bolted it to the other side oposite of the anti-backlash nuts, some just used a bearing in place, I used delrin.

look at post 27 for mine and post 34 for what rick did.

http://www.cnczone.com/forums/showthread.php?t=29977&page=3

If you have not already you may want to read through the Mod and additions sections of this link.

Joe

BobLWeiss
05-30-2007, 08:27 AM
Thanks Joe for the tip. I did read that thread and keep up with it. The only problem I have now is that I only filed down the ends of the Y axis rod to fit the bearings and not the whole rod so adding a bearing on the other side of the carriage assembly isn't going to work unless I file the whole thing first.

The good thing about the 1/2"x10 5 start rod is that it doesn't need filing. Its just like the 1/2"x10 1 start rod in terms of diameter.

I might make something out of HDPE and use that intead of an actual bearing. I can then make the hole a tad larger than 1/2" to fit the rod.

Bob

joecnc2006
05-30-2007, 08:37 AM
Thanks Joe for the tip. I did read that thread and keep up with it. The only problem I have now is that I only filed down the ends of the Y axis rod to fit the bearings and not the whole rod so adding a bearing on the other side of the carriage assembly isn't going to work unless I file the whole thing first.

The good thing about the 1/2"x10 5 start rod is that it doesn't need filing. Its just like the 1/2"x10 1 start rod in terms of diameter.

I might make something out of HDPE and use that intead of an actual bearing. I can then make the hole a tad larger than 1/2" to fit the rod.

Bob

Yes i had the same problem, thats why i made mine out of Delrin so it would last a while.

where did you get your 1/2"-10 five start?

Joe

BobLWeiss
05-30-2007, 08:47 AM
Same place I got the other one. MSC. It was something like $70 for a 6 foot rod. I am using dumpsterCNC's anti-backlash nuts on it too. I should be able to get it installed tonight when I get home from work. I got the pipes installed yesterday and everything seems to line up nicely so far.

Can you share your files for the anti-whipping blocks? It would save me some time.

Thanks,
Bob

joecnc2006
05-31-2007, 12:35 AM
Here is a simple one i made. Stock is 0.50"

the v-carve, DXF and tap files zipped.

Even if you do now own V-Carve pro you can view it with the trial version i believe.

Joe

BobLWeiss
05-31-2007, 08:25 AM
Thanks Joe!

I got the X axis working last night... what a BIG DIFFERENCE the new leadscrew makes. I am getting 250+ IPM rapids and its so smooth and quiet! There is absolutely no whipping in the X axis. It was definatly worth the effort.

I am going to finish putting together the bed tonight and start cutting some test cuts.

Bob

BobLWeiss
06-01-2007, 04:45 PM
Here are pictures of the completed machine. I added 2 pieces of birch plywood on top of the top deck sides to prevent dust from getting on the rails of the X axis. The reason I choose the plywood was because I am going to screw down T-Tracks and the MDF doesn't take screws too well.

Next up is the electronics. I already have the drivers and power supply working from my previous machine but I wanted to put it all neatly in cases. I will post pictures of that this weekend.

Bob

joecnc2006
06-01-2007, 08:38 PM
Thats a nice looking machine, Hope you get alot of enjoyment out of it. :)

Joe

santiniuk
06-02-2007, 04:29 AM
Great to see you back on the scene Bob.

Quite a transformation from the 1st machine. Paint job looks great !

Looking forward to seeing it in action.

Cheers :)

BobLWeiss
06-02-2007, 09:37 AM
Thanks!

Yes this is a BIG improvement from before. I finally got a house with a garage so I have the room for the larger machine.

Working on the electronics today..will post pictures of that setup soon.

Bob