Author Topic: My desktop CNC Build (many pictures)  (Read 41338 times)

travis77

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My desktop CNC Build (many pictures)
« on: August 23, 2009, 08:55:56 PM »
Crazy right? Worked first try. I was amazed. Im only tripping up on something small, hopefully I can figure it out.. But here is a small build log with lots of pictures! If you have any questions, I'd love to hear them. Or ideas to make it better that Im not aware of are all welcome :)

Here is my CNC when I first built it. I designed the dimensions and stuff myself using the aluminum angle rails and skate bearings idea.





I then a day or two later re-designed my Z axis because I didn't like it, and I had a hard time putting together the lead screws with the old Z axis design. By the way I am using the 1/4" by 24 all thread from the hardware store with long nuts as my lead screws. They're kind of noisey but they are working fine so far.





My stepper motors came in the mail, I bought them used on ebay. They are 180 oz-in unipolar, 6 wire motors, 3 amps, blah blah but hey they are working great and only at half power (currently running them at 1.5 amps). So I put the motors on, and I used another 1/4 inch coupler that I drilled out, tapped and put a set screw in to tighten to the shaft. By the way I found this awesome 7 wire sprinkler wire at Home Depot that has 7 individual strands in a black wrap that worked out really well. It was $0.35 cents a foot... I'd recommend if you dont want to bundle a bunch of your own wires.






Next came the driver board from Hobby CNC that I put together. It didn't take long at all, but I was being overly careful and tripple checking everything. After it was all together I thought about how I should have made a little time lapse of putting the board together piece by piece and made a clip of it... O well, next time.





The driver board was then hooked up to the computer ATX power supply that i hacked for my cnc project. Im going to post a build on that, I had time to kill while my electronics came, so I spent a bunch of time and effort on making it look nice with a plexiglas top and a printed display beneath. But here's a sneak peek:




Finally it was all coming together... Ill list specs below on what Im using and everything. I swapped out the dremel for a pencil for testing, and then a modified double spring loaded pen that I hacked which turned out to work really well where it allows the pen to float a little but still maintain the proper pressure against the paper.
I guess I should post a picture... I'll update tomorrow.





So thats the quick and simplified version of my CNC build. Ill be posting some updates and finished products later. I was also thinking about putting up a sped up video of it drawing something until I get my dremel back on it.

Now that everything is working, I'm already thinking about how Im going to build version 2.

Specs:
Cutting surface: 12" by 12" by 5"
Lead screws: 1/4" by 24 threaded rod with long coupler nuts
Motors: 180 oz-in, unipoloar, 6 wire, 3 amp
Driver Board: Hobby CNC EZ Driver board
Power Supply: Hacked ATX computer power supply running at 12 volts (now used to run the cooling fan for the driver board)
          Update: New 24 volt power supply to run the motors. Ordered from Probotix.

Software:
3D: Sketch up / Trying to figure out how to use my Solidworks or Inventor
CAM: CamBam
CNC: EMC2 running on Ubuntu 8 (Linux)

Bill of Materials:
  - Aluminum Angle Iron $15
  - MDF sheet $15
  - Skate bearings $25 (got these from big 5, cheapest I could find not ordering online)
  - Hobby CNC Ez Driver Board $71 shipped (highly recommend if using a unipolar setup)
  - 180 oz steppers $50 on ebay
  - Lots of random nuts, bolts, rod, pipe: Cannot give a true dollar estimate since I purchased some and had some stuff already in the garage. Estimate $30
  - 20 feet of 7 stranded sprinkler wire from Home depot for the motors $7
  - And I've spent $26 dollars on a 4 piece router bit set and a 6 dollar dremel bit that hopefully will be put to use sometime to engrave something.... sadly I now have the router working so its been decommissioned for the time being.

So if Im not missing anything... the grand total is $239 Keep in mind I have a LOT of extra nuts and bolts and random supplies in my garage so I was able to save a bunch in that area.

Edit: So I've purchased a few more things
  - 4' x 8' MDF at home depot $27
  - Stocked up on 1/4" nuts, nylon nuts, bolts and washers at this awesome place in Sacramento called Rainbow Fasteners, they sell fasteners in bulk $23
  - $35 hard drive to get this donated Dell computer up and running EMC2 (going to be my dedicated garage cnc computer) The guy gave me monitor, tower minus the hdd, keyboard and mouse for free.
  - $5, 2 foot copper pipe from home depot used for Z rails. Im starting to hate home depot... Im not impressed with their quality of stuff for the money I spend.
« Last Edit: September 10, 2009, 10:48:24 PM by travis77 »


Davetech

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Re: It works! (many pictures)
« Reply #1 on: August 24, 2009, 02:45:10 AM »
Wow Travis! Thanks for the tour! 

That's a great looking machine you have built. My complements on your building skills too. (I'm jealous of your workshop, I can't turn around in my little space without tripping over something).

I think those motors will serve you well. My motors are only 1 amp and I was surprised at how strong they are. I may upgrade them someday if I get lucky on eBay. Really nice output interface on the computer supply. How did you apply the lettering around the terminals? It looks very nice. I wonder though if you won't be wanting more than 12v when you start speeding the motors up. Did you combine all the yellow lead wires in the psu as suggested at http://www.reprap.org/bin/view/Main/PCPowerSupply ?  My attempts at using an ATX supply were unsuccessful. It kept shutting down as soon as the motors demanded current, but I didn't combine the wires.

Thanks for the tip on the sprinkler wire. I'm running my motors in bi-polar mode so only 4 wires are needed. I used 4-wire telephone cable but I'll pick up some of that sprinkler wire because I'm sure it will come in handy somewhere down the line.

Keep us updated on improvements  :)



BackyardWorkshop

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Re: It works! (many pictures)
« Reply #2 on: August 24, 2009, 04:37:47 AM »
Wow - very nice work!

I really like the power supply thing - and have the same question about combining the yellow wires :) I have a bunch of old PC power supplies and a few other CNC ideas I want to play with and I think I'd like to make a few like yours there - very nice touch

I also like the pencil drawings :) hehe - I'm off to make a pencil holder now!

great job all around!

Jamie
Check out my CNC projects (and more) at http://www.backyardworkshop.com

travis77

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Re: It works! (many pictures)
« Reply #3 on: August 24, 2009, 08:27:37 PM »
I posted my power supply log for those who were wondering: http://cerebralmeltdown.com/forum/index.php?topic=34.0


Here's a quick update. Today I worked on a little base to hold the Hobby CNC driver board. I also made a heat sink for the driver chips, and added a fan on top to finish it off. Im going to be adding some D-sub connectors, one for each motor just to have quick connect and disconnect. They're cheap at Fry's Electronics, I just have to driver over there sometime. Ill post some pictures below. By the way I now highly recommend the Hobby CNC EZ driver board for unipolar motors, now that its working flawlessly for me. It went together easily (simple soldering skills) and it a good all around little package. Im very happy with that purchase. They say 12 volts is a minimum voltage to run it, but I've been doing it with my ATX power supply (12 volts) and haven't had any problems.




                There are little nylon spacers that I found at ace hardware to stand the board off of the wood. The long bolts you see are countersunk from the bottom of the wood plate. I used a piece of leftover plexiglas, cut a hole in the center and then mounted the fan then the little screen guard with some zip-ties. The fan was salvaged from some old power supply that died.



            Here's the heatsink I made. They say to use flat stock aluminum but I had some leftover aluminum angle so I used that instead.



            I did have to modify it a little. I filed out a half circle since a capacitor was in the way.

« Last Edit: September 09, 2009, 08:52:46 AM by travis77 »

BackyardWorkshop

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Re: My desktop CNC Build (many pictures)
« Reply #4 on: August 25, 2009, 04:20:14 AM »
Great job on the Hobby CNC board too! That's the one I use as well and can vouch for it's reliability and ease of assembly :)
Check out my CNC projects (and more) at http://www.backyardworkshop.com


Gabriel

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Re: My desktop CNC Build (many pictures)
« Reply #5 on: August 25, 2009, 04:25:49 PM »
Whoa! Somebody sure has been busy. That looks unbelievably awesome. I saw the power supply too. It looks incredible.

Did you design the CNC yourself? I don't think I've seen that exact one before. If you did, you should put together a set of plans or something because there isn't really much out there with exact dimensions. It would make an awesome addition to that website you said you were thinking about making.

I like how the y-axis stays in place while the x-axis just moves underneath. I've found that a lot of precision can be lost in the y-axis gantry through the bearings that let it move along the x-axis. Yours doesn't have them though, so you should be able to do intricate work with ease.

travis77

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Re: My desktop CNC Build (many pictures)
« Reply #6 on: August 25, 2009, 10:16:48 PM »
Thanks! Haha ya I have been busy with this thing.

I did design the build myself. When I was first starting to design it, I made a folder on my desktop and saved a whole bunch of different DIY CNC builds. I then started to go through them and picked out the ones I liked. I took ideas from a bunch of different ones and synthesized my own. I didnt want to do the moving gantry because I thought that it would be better to just move the X axis seprately since a moving gantry is a lot more weight to move around. I think my second revision will expand the X and Y directions with the addition of a router for the cutter.

That is a good idea about making some plans. I think if I did get a little website up and running I definately would. I actually designed the whole machine on CAD before I built it. So I knew the stuff was going to fit and what not.

I should be posting some updates in two or three days so check back then :)

travis77

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Re: My desktop CNC Build (many pictures)
« Reply #7 on: September 01, 2009, 09:20:43 PM »
Okay I've got an update. Well actually two. So here it goes...

A few days ago, I received my 24 volt power supply that I purchased from Probotix. So Im now powering my CNC machine with that thing. The motors seem to warm up if I leave them turned on idling. Thats where the Hobby CNC's Pro Chopper board with the idle current reduction would probably help out, but I didn't want to spend the extra cash on that, so I just unplug the power when my machine is idling.



Next update is today I decided to mount an air die grinder to my CNC machine... I haven't seen anyone try it yet. But I can see why they don't. Its not practical really, unless you have an amazing air compressor. My air compressor just cant sustain the 60-80 psi i want continuously while the grinder is running. The grinder draws more air than the compressor can pump out. But it works for a few minutes. I ran a quick file I made on CamBam. I learned how to use the pocket tool on a small square I drew. I posted up a video, check it out.



Air Die Grinder CNC Square Pocket


Now my goals are to:
    Get a router and re-design the Z axis to better support it.
    Make a control board to mount the driver board and two power supplies. 24 volt runs the CNC board and steppers, 12 volt runs the cooling fan so i dont blow it up on 24v.
    Get some DB9 or similar connectors and make mounts to hold those in place.

BackyardWorkshop

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Re: My desktop CNC Build (many pictures)
« Reply #8 on: September 02, 2009, 04:24:14 AM »
Hey that's pretty cool - I haven't seen anyone trying to use air tools before either :) good try

I was throwing around the idea of using a die grinder as a spindle for this sewing machine motor I have - but haven't got around to playing with it yet... My router's slowest speed is like 8000 rpm and that's too fast for milling metal I think
Check out my CNC projects (and more) at http://www.backyardworkshop.com

travis77

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Re: My desktop CNC Build (many pictures)
« Reply #9 on: September 06, 2009, 11:59:45 PM »
You guys have been pretty quiet lately. I have some updates on my build.

I now have a working router mounted and is cutting out parts. The first thing it spit out was a sample gear. It took me a while to rebuild the Z axis to hold the router since it is so heavy and large in comparison to my desktop sized machine. Im not really happy with the tolerances of the Z axis, there's a little bit or rocking if i grab a hold of it and move it. But at least it is working for now. Im debating on machining out a new Z axis with the router so it would be perfect, or to just build a completely new second machine. Knowing me... Ill probably end up doing them both in that order.. For now though, I need to mount my driver board and power supplies to a control board and get my donated dell computer a new hard drive and turn that into my dedicated garage cnc computer. Also dust control is needed... or i might make a rolling table that holds everything and just wheel it outside when running it. Sorry for the rant, here's some pics.











Gabriel

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Re: My desktop CNC Build (many pictures)
« Reply #10 on: September 07, 2009, 01:44:00 PM »
I personally have been quiet because I haven't had anything interesting to say. It's sad I know.  ;D

I've mostly just been working on my site to try and get it up to date with all of the projects that I have worked on over the last month. Apparently I've had a successful month because I have a ton of documenting to do still.  :o

Anyway, your CNC is looking really good. Out of the two CNCs that I have built, neither one had perfect Z axis tolerances. I built my second one hoping that it would be better, but it wasn't. I eventually gave up trying to make it perfect because I wanted my hobby to be making stuff with a CNC not adjusting one endlessly in an attempt to get it perfect.  :D I guess it really depends on what you're making though, but I'd say that that gear you made is about as perfect as it gets.

Can't wait to see what you come up with next!


travis77

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Re: My desktop CNC Build (many pictures)
« Reply #11 on: September 07, 2009, 04:14:03 PM »
I eventually gave up trying to make it perfect because I wanted my hobby to be making stuff with a CNC not adjusting one endlessly in an attempt to get it perfect.

Thats very true.. There's something up with my Z axis not cutting down to .75" when I tell it to.. I told it to cuz .8" down and it didnt even make it through the 3/4" mdf..  >:( Im not sure whats up, maybe the motor is losing steps since its heavy or binding I dont know. Ill have to just play around with it.

Hey Gabriel, when you cut a part completely out of MDF, do you have to clamp that piece down too before you start somehow? What happens when the CNC finishes, will the part get kicked out by the router and go flying if I dont clamp it down?

Davetech

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Re: My desktop CNC Build (many pictures)
« Reply #12 on: September 07, 2009, 05:27:24 PM »
Good lookin' machine there Travis.  I see you made use of electrical conduit for your Z rails. Interesting gadget you have holding that sealed bearing with rubber hose? How's that work?

I've been quiet too, although I've been answering a few of the questions on Tom's Instructable. I haven't seen him respond since last spring, so I've tried to field a few of the questions myself.

I've also been reworking my machine, including the Z-stage. I had finally gotten everything working well enough that I tried to make my heliostat control board and it just barely fit the working area my machine had. I still don't know how I did it but I managed to botch the alignment and some of the traces ended up off the board. Wasting a 6"x8" piece of double-sided ticked me off enough that I said "That's it! I need more room!" And I proceeded to tear the machine down and replace the 10" iron pipe legs with 18" ones. That allowed me to space the X rails 15" apart instead of 9".  Made lots of other changes too but I'll detail them later on the easy mill thread.

travis77

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Re: My desktop CNC Build (many pictures)
« Reply #13 on: September 07, 2009, 08:28:45 PM »
Thats nice of you to help out answering some of those questions.

That interesting gadget is just a U-bolt with rubber hose on both sides to center the bearing when its not tightened down. I didnt really choose the conduit pipe for the rails, it was just something I had laying around. Unfortunately it wasnt the nicest material to work with, since the outer diameter isn't 7/8" nor 1" and I didn't have a drill bit between the two so its got a tad bit of play. Oh well....But hey it works perfectly fine so far.

Ill have to check out your update when you get around to posting it. I know what you mean about cutting space... always seem to never have enough.

Gabriel

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Re: My desktop CNC Build (many pictures)
« Reply #14 on: September 08, 2009, 07:07:04 PM »
I swear, no matter how big your CNC it always ends up being just a little bit too small for the job at hand. One day I would like to have one of those CNCs that is so big that you can throw a 4'x8' piece of plywood down and still have room to spare. Of course, I'm sure even then I would find something else that is too big ;D

To answer your question about clamping MDF down Travis, I think the best thing to do is to design the part that you are cutting out with tabs which will hold it in place while the CNC cuts it out.

Here's a couple of pics as an example.




The tabs are then later removed with a dremel or something similar.

Granted, I never used to bother with tabs, but I've now learned that they can help to keep the part you are cutting out from being damaged on the edges.

Of course, it depends on what you are cutting out. For example, if I was going to cut out a gear like what you had in one of your pictures earlier, I probably wouldn't use tabs. Instead, I would just watch the CNC closely as it approached the end of the G-code with my hand on the stop button in case something went wrong.