How to build a Custom CNC

[Bill_Hancoc]

Engadget has a really great 2+ part article on how to build a Home CNC. This is part one of ??? I will post the links to the later parts as they are posted...
If any team doesnt have to money for a 2 million dollar HAAS machine but still wants a small CNC for making parts check this out


(I realize not all HAAS CNC's are 2 million dollars but it sounds good for the purpose of a shock factor)

[neslo89]

Our school uses an old Bridgeport Series I from the 1970's. This would be so cool to have...fun to play around with during my free time . I am definitely thinking about doing this.

[JoelP]

Sounds like a really fun pre-season project! I'll be looking into this.

[techtiger1]

Originally Posted by neslo89

Our school uses an old Bridgeport Series I from the 1970's. This would be so cool to have...fun to play around with during my free time . I am definitely thinking about doing this.

Aww come on man you know those old Bridgeport's are fun! . Definitely a cool link I would really like to have one for myself actually. Kinda reminds me of the mask making machine in MI3 the movie. At any rate awesome stuff.

-Drew

[neslo89]

Originally Posted by techtiger1

Aww come on man you know those old Bridgeport's are fun! . Definitely a cool link I would really like to have one for myself actually. Kinda reminds me of the mask making machine in MI3 the movie. At any rate awesome stuff.

-Drew

Oh don't get me wrong I love that machine

[Not2B]

OK... if you want to try this - here is the ultimate resource:

CNC Zone

Lots of help for DIY CNC machines. Very VERY good resource.

[sanddrag]

As soon as I get the money I will be converting my Sieg X1 mill to CNC.

[Gabe]

Hey, they show you how to make a Lego USB flash drive!!! Awesomeness!!!
http://www.engadget.com/2006/05/26/t...o-flash-drive/http://

[DonRotolo]

Maybe 10 years ago, Nuts & Volts had a mult-=part article on building a CNC 3-axis mill for about $400 (then). The XY table used 2 pairs of ball-bearing drawer slides (the good kind, with no play) and a dremel as the cutting tool, like this one.

Remember that a dremel is somewhat limited. Don't expect to cut aluminum with it, at least not quickly.

Regardless, definitely a project worth considering. The hardest part is the stepper driver, next is finding software for that old PC so the parallel port can be used to drive the motor driver. You can buy pretty good lead screws for not much more than the 1/4 inch all-thread the article suggests, and end up with 0.001 repeatability on 0.0005 accuracy.

If you attempt this, just think about what you're trying to accomplish, and don't cut corners where it matters. X, Y and Z must all be perpendicular to each other - perfectly. No play or wobble, in the lead screws (use plastic nuts, they last forever and have no backlash), or on any of the axes. Big is good, but too big is bad, becuase you get wobble. Why does that bridgeport weigh a ton?

Don

[lukevanoort]

Originally Posted by Don Rotolo

Remember that a dremel is somewhat limited. Don't expect to cut aluminum with it, at least not quickly.

Agreed, we killed my Dremel this season cutting 1/4 aluminum plate. (And I mean killed, like doesn't work, period, I think I might try new brushes) Actually, I wanted to do something similar, I was going to try and make a laser cutter thingy, sorta like a waterjet/plasmacam. I was going to use potentiometers and heavily geared down globes so it would move slowly to increase accuracy. The cutter was going to be a CO2 laser, but I was unsure of how to "terminate" the laser beam after it cut through the metal. I might just build a CO2 laser for the fun of it, they're cool little things, a well made one has an invisible beam but generates a LOT of heat. Then I'd have to figure out shielding.... hmm.

[Bill_Hancoc]

Originally Posted by Don Rotolo

Why does that bridgeport weigh a ton?

Don

So it doesn't flex and lose accuracy whilst making a heavy cut and stays perpendicular...this is why a small smithy lathe/mill/drill press are not that great since they have no structure to them and flex and lose accuracy

[sanddrag]

Originally Posted by Don Rotolo

next is finding software for that old PC so the parallel port can be used to drive the motor driver.

I have just the thing. TurboCNC. Free and fits on a DOS boot floppy and will run on anything higher than a 486.

[Not2B]

I'm going to retrofit an old Emco F1 CNC mill this summer. The school was getting rid of it, so I thought I could repair it and get it working for simple stuff for the team. I mean - better than nothing, right?

http://static.flickr.com/58/16500066...73e819.jpg?v=0

[Not2B]

Originally Posted by Not2B

I'm going to retrofit an old Emco F1 CNC mill this summer. The school was getting rid of it, so I thought I could repair it and get it working for simple stuff for the team. I mean - better than nothing, right?

http://static.flickr.com/58/16500066...73e819.jpg?v=0

WOO HOO! As of today, around 3:30 pm EST, the retrofit baby mill woke up, and moved. The way I wanted it too.

Just gotta get the spindle spinning and then we can make... uh... really really tiny things. 4" by 8" window to machine in. That's big enough to make gear box parts I figure.

Besides, even if we never use it, the team can learn what IS possible.

[DonRotolo]

This was what I ended up building, based on the Nuts & Volts articles: A custom 3-axis CNC controlled milling machine. I have it configured as a PC Board drilling machine, but I just need to change Dremel bit and the hold-downs on the table and it'll mill whatever. Slowly.

What the pictures don't show is that it's mounted on a cart, with an IBM PS2 PC (8086 processor, with 8087 math co-processor, 4.77 MHz, 640k RAM, bad HDD and 730 k 3.5" floppy drive).

The first photo shows the overall work area. Travel is X=9.75", Y=10.5", and Z=4". Speed is about 3" per second max, when drilling this is not bad, for milling it takes forever. Precision is 0.00025, accuracy is about 0.005 in 10", repeatability is +/- 0.002 inches. Note the Dremel mount for the Z axis. A Roto-zip could also be mounted there for milling, has a LOT more power than the Dremel.

Sure beats drilling by hand.

The second photo is a close-up of the Y axis. Note the end-position (home) switch, the red plastic no-backlash nut, precision lead screw (about $15 for a 3' piece), the rubber hose coupling the screw to the motor shaft, and most importantly the "drawer slides" used for the X and Y axis rails.

It has about 100 hours on it and still works great. Nothing has broken yet.

Don