View Full Version : Another one in the works..

08-02-2004, 03:35 PM
Hello to all..
Time to "GetErDone". My name is Chuck and I've been lurking about for awhile reading and learning, tryin to come up with a working design.
Since I seem to have alot of extrusion lying about, I figured it would be my best option for a frame. Did the Ebay thing and bought a bunch of worthless stuff, but did manage to get some THK slides and then bought some ballscrews from Reid.
I chose to go with a moving gantry, the gantry uprights are 6061, 1/2" by 8 and 3/4" by 23 and 1/2".
The frame worked out to be about 32 and 3/4 by 35 inches, if I can get a 18" cut, I'll be happy.
The extrusion is by 8020 and is the 2020 and 1020 series.
I'm using regular end connectors.
The steppers for the x and y are NEMA 34 and are expected to give me 420 oz-in. They are rated at 4.8v @ 2.53a. They are 6 wire so I'll be running them in bipolar series.
The z will have a 306oz (unipolar, not sure what bipolar will give) 6v @ 2a
I haven't bought the drives yet but I'm sure they will be gekos.
I did go ahead and get the "PC-to-route" breakout board.
I will be using Mach2 and autocad.
I started the assembly a couple days ago and took some pics along the way.
Also took some pics of me trying to repair a ball nut that dropped a few balls due to my carelessness.
the ideal was simple and it worked :)
Tonight I will be working on the y and some pieces of the z, I'll take more pics along the way and I'm sure ask alot of question.
take a look and Please offer your suggestions....this is all new to me and I'm making it up as I go..any advice is more then welcomed.
Thanks in advance,

08-02-2004, 03:39 PM
This is where I'm at ...lot more to go..http://cnczone.com/gallery/data/500/36420024.jpg

08-02-2004, 03:42 PM
And another...check out my gallery for more


08-02-2004, 04:07 PM
Looks like a good start! Super stout frame, I like it.

08-02-2004, 04:14 PM
Looks to me like you got some nice stuff and you don't need much help either. Looks good!


08-02-2004, 05:16 PM
Thanks yall,
I'll go through the pic sequence.
Pics 1 through 5.
This shows the drilling of the access holes for the end connectors.
the little drill jig from 8020 helps keep everything lined up. the #7 hole doesn't leave much room for error, sometimes I have to redrill with a 1/4 to get the 5/32 allen wrench to hook up with the button heads.
Snug em down and it will be there for awhile.

08-02-2004, 05:21 PM
pics 6 through 8 show the finished rail and the feet ready to be taped...48 holes threaded to 1/4-20.http://cnczone.com/gallery/data/500/36420008.jpg
glad thats done! a cordless and a sharp tap makes all the difference....oh yea..magic-tap also helps. :)

08-02-2004, 05:29 PM
Here is the motor mount and the simple end bearing block.
I will end up cutting off the wings on the motor mount. my ballscrew is only 36" with 3" turned down, so I ran it up between the center rails. I had already drilled the 1/4 inch holes on the side so it hooked up with the tslots in the extrusion...downside...I'm sure I will have misalignement somewhere...tweaking will be called for.

08-02-2004, 05:34 PM
Swiss Cheese! :) http://cnczone.com/gallery/data/500/36420019.jpg
Both sides were milled at the same time sandwiched together.
plenty of 1/4 inch holes for whatever.

08-02-2004, 05:41 PM
here are the cross support rails
acad said they were 10.359375...somewhere around 10 23/64"...I'll cut these on the mill..thank goodness for the DRO..milled all 6 at the same time to be sure of assembly square-ness

08-02-2004, 05:47 PM
remember that misaligned thing i was talking about..here it is http://cnczone.com/gallery/data/500/36420023.jpg
I didn't even notice untill I looked at this picture that my assembly marks are on the wrong end...that should take care of the misaligned motor shaft to the ballscrew I'll put that on my "to fix" list...moving on...

High Seas
08-02-2004, 05:49 PM
Lookin' My-T-Fine! That 2020 and 1020 is some pretty heavy duty stuff - and the 6061 plate fits in well. Did you draw out the design in autocad - or just sort of plunge in? Its such a machine to be proud of - others might take the same path if you had some dxf files. But, the nice thing with the "Big-Boy's Tinker Toy Set (80/20)" is you really don't need the plan - you can just start and see what fits where... Is your plan to cut metal with a really big router- looks like the rig for it.
More pics
cheers - Jim
your post came in while I was finger fiddling on the keyboard - good alignment compensation!

08-02-2004, 05:59 PM
Here is my fix of the ballscrew that I spoke of in post 1.
I dropped 3 balls out of the nut when I was transfering it to the screw...the cardboard carrier tube had a inside bore bigger then the turned down 3/8 ...longer tale shorter....balls hit the workbench...I was luckey I was over the bench or i wouldn't have seen them fall out...ANYWAY...
Took a 1/2 inch piece of roundstock and bored it to 3/8
Then drilled a hole a little bigger then the ball...
transfered the nut to the roundstock quickley so has not to loose another ball in the hole....http://cnczone.com/gallery/data/500/36420029.jpg
put a ball in the hole and the roundstock onto the screw....
pushed the nut towards the screw until I felt it make contact with the ball...
rotated the roundstock till the ball was facing down....
turned the nut and the roundstock in different directions while pushing towards the screw....
once the nut starts catching the threads on the screw, I kept rotating the roundstock back and forth till the nut is all the way onto the screw...

08-02-2004, 06:02 PM
the ball is back where it belongs :) :) :)

08-02-2004, 06:12 PM
Thanks Jim...
I do have some drawings but I'm not sure if any would be useable or not...when I get done I'll toss em into the ring and maybe they'll do some good for someone...
The 8020 makes everything really simple....plus all the stuff is already drawed up....I drew it up in the rough and imported the extrusion files and then changed the scale matched up with my bearing rails and blocks.
I tend to make alot of changes from my drawings on the fly because it "just seems right"...
plus I always drill xtra holes when I have my zero dialed in on the part...ya never know when a xtra hole will come in handy :)
I plan on cutting only wood products....aww whom I kidden...If this cuts air...I'll be happy....I know NuTTin about cnc codes and the such..I just enjoy building stuff :)

08-02-2004, 07:00 PM
And now the questions begin...
I wanted to wait till the table was done before I stared thinkin bout electrons...but I feel i should go ahead and order the stuff to build the power supply...First let me say..I've been a Electrician since 79' but I've yet to build a power supply to power steppers...with that said..
Here's the stats:

stepper x nema 34, 420 oz-in, 4.8volts @ 2.53 amps
stepper y ditto
stepper z nema 34, 306oz-in (unipolar) 6volts @ 2amps
these are all 6 wire so they will be hooked up full windings / series

I have read the white papers and every post in this forum that have transformer in the title.
I'm thinkin a Plitron 750 va, 40vdc @ 9.38 amps (#107026201)
OR maybe...
i have a bunch of transformers that are 24v that should put out somewhere around 8 to 10 amps.....can I build 2 power supplys and hook the outputs in series? Never done that...not even sure if its safe ....same ac phase input should be ok...right? I could get my 40+ volts that i want and it wouldn't cost me anything...I have the bridges, not sure about the caps..but even so...big cost savings..
Any commits? good ideal...bad ideal?

08-02-2004, 08:49 PM
As long as you don't go over the max current of 1 xformer, it should work, if you convert to dc before you series them. If you do let the smoke out of somthing, it was a free fireworks show:)

High Seas
08-02-2004, 09:49 PM
If you do let the smoke out of somthing, it was a free fireworks show:)
THAT'S never Free!
But it counts as Experience!
:cheers: Jim

08-02-2004, 10:31 PM
He said he already has the parts!

08-03-2004, 03:56 AM
thanks DSL, I think I'm gonna give the 24v transformers a try...I like free..free is good thing. If it doesn't look right or safe, I 'll go the other route.

08-03-2004, 04:53 AM
Why don't you use a PC power supply to supply some juice to your rig? Plenty of amps and mighty cheap! Not to mention the time saved by not building a supply from scratch. That's what I'm doing with my machine.


08-03-2004, 06:22 AM
Thanks Paul for the tip, but I think I might need more volts.
I bought this one this morning:
MPR25 (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5712776324)
When and if I upgrade to servos I will be able to use this same supply.

08-03-2004, 10:41 AM
Hey Chuck, looks like that power supply is the negative voltage kind; minus 48V. It might be hard to hook it up to the rest of the setup.


08-03-2004, 01:04 PM
the unit is used in the telecom industry to charge a bank of battery's. in reguards to dc voltage, postive or negitive doesn't matter. has long as the + pontential is hooked up to the correct (+) connection point on the drive.
I'm pretty sure the output connection points are labeled correctly. I think the dash in front of the 48 was not there to mean negative 48 volts, but if it is I will reverse the leads. The amount of voltage is in reguards to a ground or zero pontential. Then again...I have bought useless stuff from ebay on more then one occasion :)

08-03-2004, 05:53 PM
As long as you don't go over the max current of 1 xformer, it should work, if you convert to dc before you series them. *snip*

You can hook them up in series before rectification as well (as long as you won't run them from different phases, but why would you do that?). Make sure you don't hook them up "anti-phase" which would give you 0 (24-24) volts out. If you do, just flip one pair of wires around (so you get 24+24 :)).

Be aware that if they are 24 VAC you will get >65 VDC after rectification (48*sqrt(2)). But you being an electrician this might not be news for you :)


08-03-2004, 06:00 PM
Thanks Arvid,
I didn't know that, I guess I'm a different type of Electrician...
I've never had to hook up two transformers in series before..
Anywho I went ahead and ordered a switched power supply...48vdc @25amps off of ebay.
But thanks for the info. I'm learning new stuff everyday here :)

08-04-2004, 09:34 AM
You're welcome :)

The higher DC voltage is not because there are two transformers in series, but because of the rectification process. So one 48 VAC transformer would also produce some 65 VDC after rectification. 48 VAC refers to effective voltage, while after rectification you get the peak voltage (minus some diode losses and ripple).


08-04-2004, 02:19 PM
I've managed to get some more work done on the y and z.
Everything is connected on a trial until i can get some measurements.
I'm ready to drop in the z axis ballscrew as soon has I get it turned down and the bearing holes bored. Maybe in the morn....its 100 degrees outside...east Texas quittin time :) http://cnczone.com/gallery/data/500/36420039.JPG

08-04-2004, 02:21 PM
and another...

Do ya think the clamp will be strong enough?

08-04-2004, 02:24 PM
And one more...


see the gallery for the rest....more to come.... :)

High Seas
08-04-2004, 03:04 PM
Given the robustness of many of those components - WOW that's a MASSIVE clamp and router - you'll be ready to re-configure the bed to a 4x8 in no time!
Well, new rails screws etc - but WOW - thats huge.
Cheers - Jim

12-23-2004, 02:09 AM
can you fix the pictures please