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My homebrew CNC

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vinito:
I just finished up a CNC machine I've been building over the past couple months. Today I just had to assemble it making sure things were square and parallel, etc.
I intend to use it for isolation milling for prototype PCBs. That should be nice for proving out a design before sending files to a board house to have some professionally made. I'm a machinist and this design is intensive in that area, so wouldn't recommend it specifically to anyone not skilled in the field. There are designs out there which are much easier to make. Now in electronics I'm a green hack at best, so time will tell what kinds of things the machine will end up making, but fortunately I have a buddy who is my electronics guru. This was actually a product originating from our paired desire to create some cool electronics widgets, so it actually stands a good chance of being a very useful machine.

It could also machine some small parts in soft materials too, and of course do some engraving as well.

It's not actually "complete" as there are a few things which will be improved in the future (such as a better spindle and various other things), but as of today it's a working machine and capable of doing some work.

I built it on the cheap for the most part. Much was pulled from the scavenge and scrap pile. All together the bought stuff totaled around $100 (driver board, power supply, hardware, etc.).

Couple for overall view.





Here are the driver board and power supply.

BANE:
nice job and looks quite rigid,
I've been considering making something like this for pbc too since the printer toner method seems not to be working well for some of the boards ive made

--- Quote ---$100 (driver board, power supply, hardware, etc.).
--- End quote ---
can you provide a bill of material for the electronics?

Also, are those linear bearings you're using?

vinito:
I've heard mixed reviews on isolation milling PCBs, but having been in machining for a while I've learned that many of the things you think should be simple end up needing a bunch of head-scratching and tweaking to get the process ironed out and dependable. I think that must be where the negative reviews come from because there are several sites I've seen where the authors are getting some very good results. It's a matter of working the problem and learning a process that works well for you, which will happen if you keep at it. By all this I mean to say that I expect to have a bunch of problems at first, but also expect to get it figured out.
Here's a link showing some pretty simple successful methods.
http://millpcbs.com/

Like I mentioned in the original, several things came from the salvage pile, which include the stepper motors and linear bearings. I think if you bought motors and linear bearings off eBay you could add another $75 or so on an average day, less if you shop around. And of course you could get creative and skip the expensive linear bearings, which is what I would have done if I didn't have some in surplus.

The stepper driver was about $33 + shipping from eBay:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270706351680
(They've upped shipping $10 since I bought mine. Uugh)
That little stepper driver is popular and inexpensive from several sources on eBay, and it seems to work pretty well.

The power supply (24V 6.5A) was about $15 + shipping from MPJA:
http://www.mpja.com/prodinfo.asp?number=16854+PS
(Now out of stock. Uugh)
Of course any clear-thinking tinkerer pads the order a bunch here to spread the shipping charges out. You can always use some more heat-shrink tubing or something.

I already had wire  ;D That's about it for electronics. Didn't really build a thing there, just plug in and play. Since I can now (or soon anyway) make my own boards, that's likely to be a different story on the next project. But for the time and money involved I think I'd just buy a stepper driver unless I had special power requirements for big motors or something. They seem to pack some punch for the money these days.

A surprise to me was the dang hardware. Screws, nuts and washers totaled up after four trips to the hardware store to about $50 and can nickel and dime you to death. Granted that I probably only used 2/3 of what I bought because I had to change the design after it was "done" the first time but not performing acceptably. That stuff is just a lot, lot more expensive than I remember it to be last time I did something like this. They must be making them out of crude oil or something. I'm going to shop around for less expensive sources in the future.

Mach3 would cost about $150 more, but I purchased that already for a previous project. EMC2 would work just as well for free (some say better).


Anoroc:
I would LOVE to have a small table-top CNC router table for my house LOL. Looks like you did one hell of a job! I have a 15" wide KNK, which is only 2.5 axis, (Only up or down for the head). Since I have no real z-axis control, I can't mount a rotary head to it. Not for a lack of trying! I could probably get away with doing some plastic engraving, but that would be the limit of its ability.

garrettg84:
I'd like to see a video in action if at all possible =)

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