Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: BANE on November 26, 2008, 04:44:21 PM

Title: Hobby CNC mill
Post by: BANE on November 26, 2008, 04:44:21 PM
Hello,

So I'm looking into buying a small CNC mill with CAM software.  I have Solidworks that I'd like to be able to use with the CAM. My budget is <$1200.  Does any one have any recommendations?

Bane
Title: Re: Hobby CNC mill
Post by: pomprocker on November 26, 2008, 04:50:39 PM
Everyone says Sherline, even though I don't own one myself.
Title: Re: Hobby CNC mill
Post by: BANE on November 26, 2008, 05:06:21 PM
For some reason the design doesn't look that ridged.  But that maybe all you can get for under 1K :P

I've been looking into the Sieg X2 mini mill.

Bane
Title: Re: Hobby CNC mill
Post by: BANE on November 26, 2008, 05:12:53 PM
I like the 3x http://www.embeddedtronics.com/x3.html (http://www.embeddedtronics.com/x3.html)

This one looks more rigid http://www.lathemaster.com /HEAVYDUTYMILLINGMACHINE%207045FG.htm (http://www.lathemaster.com/HEAVYDUTYMILLINGMACHINE%207045FG.htm)  > Only this isn't CNC, but i think there are kits to make it.

Has anyone had an luck with these designs?

Bane
Title: Re: Hobby CNC mill
Post by: ArcMan on November 27, 2008, 09:20:06 AM
I'm going to get a Harbor Freight mini-mill soon.  I currently have a HF mine-lathe.  They are very inexpensive Chinese machines.  Not great quality, but they do the job.  The Sieg that you mentioned is the same thing.  It's also sold as Grizzly.

I like them because there is great support for them at http://www.mini-lathe.com and the Yahoo 7x12 Mini-lathe discussion groups.  There are tons of awesome projects to upgrade them to a really nice machine.
Title: Re: Hobby CNC mill
Post by: BANE on November 27, 2008, 10:25:04 AM
The Sieg from Harbor Freight is manual when out of the box, so i'd have to get a CNC kit right?  Any idea how much a kit would cost?

Bane
Title: Re: Hobby CNC mill
Post by: ArcMan on November 27, 2008, 10:35:34 AM
I don't have any links at hand for that mini-mill, but lurk around that site and discussion group I mentioned.  Those guys are very knowledgable and helpful.

Some things you should know:  1. Manual machining is more accurate than CNC machining.  2. CNC packages cost over $1,000 (much more than the HF mini-mill)  3. IMO (and most every machinist's opinion), you should learn manual machining before you jump into CNC.   CNC is used by machine shops that need to turn out large production runs of parts.  Why do you think you need it?

Title: Re: Hobby CNC mill
Post by: BANE on November 27, 2008, 11:11:05 AM
I like using CAM and most of the robot parts I'm trying to make involve arcs and circles.  But for only 1K i think it will be worth while.  If you come across some one selling a kit please let be know :). 

Quote
you should learn manual machining before you jump into CNC.
  I use a bridgeport with prototrak and have a bit of experience with milling. The only problems is that my work owns the mill :P.
 
So are you just going to use it manually ArcMan?

Bane
Title: Re: Hobby CNC mill
Post by: ArcMan on November 27, 2008, 07:47:10 PM
I'm planning on using it manually.  I've run my lathe manually for a couple of years now.  I do want a power feed though.  There's nothing worse than manually feeding a long piece through that your surfacing or channeling.

You're right about machining arcs and circles - a CNC mill does do that very nicely.

There are some nice projects out there by people who have created their own CNCs.  Have you thought about building your own?

BTW, that would suck coming home to a Chinese mini-mill after using a Bridgeport at work  :P.  At least it's yours, right?
Title: Re: Hobby CNC mill
Post by: BANE on November 29, 2008, 06:54:41 PM
Quote
Have you thought about building your own?
I have looked into it and it still might be an option; but some of the designs i would need a CNC mill to make parts for the mill :P.
Quote
BTW, that would suck coming home to a Chinese mini-mill after using a Bridgeport at work
LOL, that would be a potential problem being that i'm used to milling most steel and aluminum like butter :D. Honestly, i have no idea what a Chinese mill might be capable of :P.
Quote
At least it's yours, right?
No, :'( the place that i work at has one that i use alot.

Bane
Title: Re: Hobby CNC mill
Post by: kd5kfl on November 29, 2008, 10:27:19 PM
Quote
Has anyone had any luck with these designs?

we have one of those lathemaster mills where I work. It is an Enco variant.

The only hassle I have with it is the milling table. There doesn't seem to be a backlash adjustment. You set it up with a drill where you want a hole. You crank it an indicated 1.1 inch.

You turn the crank the other way to go back .1 inch. There is a quarter turn with no motion, then another 10 degrees where you feel the slack coming out, then motion.

The indicator shows that you have moved back .35 inches by the time the table moves again.

Which makes it something less than a milling table.
Title: Re: Hobby CNC mill
Post by: BANE on December 03, 2008, 08:45:44 PM
What about a Sherline mill?  It looks like a CNC can be got for around $2000.  They have a CAM software demo that i've tried out and like, but for $300 :P.

Bane
Title: Re: Hobby CNC mill
Post by: ArcMan on December 04, 2008, 08:53:33 AM
IMO, Sherlines are too small for robotics work, but that really depends on how big the robots that you intend to build are.  Sherlines are made for small model makers (like train models or steam engine models).  I don't have the specs at hand, but compare Sherline vs. Chinese mini-mill for X and Y travel and Z clearance and travel.

OTOH, small mills and lathes are best for small detailed work.
Title: Re: Hobby CNC mill
Post by: BANE on December 04, 2008, 04:58:33 PM
Quote
Sherlines are too small for robotics work
I would mostly be machining aluminum and plastics for things like standard size servo brackets and small chases.  They offer some kits for the Sheline 2000 8 direction thing. 

Btw, does anyone recommend buying a cnc mill from E-bay used?

Bane
Title: Re: Hobby CNC mill
Post by: Admin on June 10, 2009, 09:29:16 AM
(apologies for reviving a dead post)

I need CAM software recommendations (http://www.societyofrobots.com/robotforum/index.php?topic=8194.0) . . .