Society of Robots - Robot Forum

Mechanics and Construction => Mechanics and Construction => Topic started by: S. Karim on May 25, 2008, 09:03:37 PM

Title: CNC machines?
Post by: S. Karim on May 25, 2008, 09:03:37 PM
I want to cut my own metal...but not by hand. Id rather have a small machine do it for me. Any suggestions?
Title: Re: CNC machines?
Post by: JonHylands on May 26, 2008, 06:10:38 AM
There are a bunch of questions you need to answer first:

- how much money do you want to spend?
- how large (X & Y) a piece of material do you want to cut?
- how thick a piece of material do you want to cut?
- what kind of metal are you talking about?

I have a Sherline CNC mill, and it works well for cutting plastic, or thin aluminum (1/16"). You can cut thicker metal, but it takes longer.

- Jon
Title: Re: CNC machines?
Post by: S. Karim on May 26, 2008, 12:22:43 PM
There are a bunch of questions you need to answer first:

- how much money do you want to spend?
- how large (X & Y) a piece of material do you want to cut?
- how thick a piece of material do you want to cut?
- what kind of metal are you talking about?

I have a Sherline CNC mill, and it works well for cutting plastic, or thin aluminum (1/16"). You can cut thicker metal, but it takes longer.

- Jon

Well moneys my #1 problem right now. Maybe $500 tops for some sort of cutting system, I doubt I'll get a CNC. The biggest piece I'll cut is probably 4" x 8". Max thickness will probably be 3/8". Aluminum, brass, or maybe other materials like HDPE and Lexan. Simple materials for small robotics, but I seriously want good quality cuts (something I wont get with a hacksaw, without hours of sanding).

Sherline CNC mill is exactly what I want...but its too expensive for me. Arent there any other companies or options that sell cheaper desktop CNCs?

And also...what if I get a mill without a CNC, how do those work??? Does it mean I have to move the metal around by hand to cut arcs (or probably the drill around)?

PS. Ignore the title, when I mean I dont like cutting by hand I mean cutting with any types of saws. Especially if I need to cut shapes inside a shape...thats going to suck without a whole bunch of fancy tools.
Title: Re: CNC machines?
Post by: JonHylands on May 27, 2008, 06:08:35 AM
I built Seeker 2 with a manual lathe/mill. All the body parts were cut out with a hacksaw, and filed to shape.

http://www.huv.com/miniSumo/seeker2 (http://www.huv.com/miniSumo/seeker2)

You're not going to have much luck getting anything CNC for $500... My Sherline CNC mill setup was about $2000, and I already had the computer, and used free software.

- Jon
Title: Re: CNC machines?
Post by: shlodo on May 27, 2008, 09:04:23 AM
use a band saw, dremels are good for thin pieces too
Title: Re: CNC machines?
Post by: S. Karim on May 27, 2008, 05:41:55 PM
I built Seeker 2 with a manual lathe/mill. All the body parts were cut out with a hacksaw, and filed to shape.

http://www.huv.com/miniSumo/seeker2 (http://www.huv.com/miniSumo/seeker2)

You're not going to have much luck getting anything CNC for $500... My Sherline CNC mill setup was about $2000, and I already had the computer, and used free software.

- Jon

I love that thing! Seen a when you first posted it a while back. I always cant stop looking at how nice the gummy tires look, whered you get those?

And I've embraced pricing reality, I know $500 wont work.
Title: Re: CNC machines?
Post by: JonHylands on May 28, 2008, 06:46:02 AM
The tires are molded polyurethane. One of my friends build a mold for me, and I bolted the tire in place in the mold, mixed the two-part polyurethane compound, and poured it into the space between the mold and the wheel.

I documented the process a little better with Seeker 3:

http://www.huv.com/miniSumo/seeker3/index.html (http://www.huv.com/miniSumo/seeker3/index.html)

Go down to the October 4, 2006 entry, and you can see the mold with the wheel beside it, and mounted in it. In the October 22, 2006 entry, I show a picture of the finished wheels, and the molding compound I use.

- Jon
Title: Re: CNC machines?
Post by: Brandon121233 on May 28, 2008, 01:52:05 PM
depending upon how handy you are you can try to make your own, http://www.instructables.com/id/How-to-Make-a-Three-Axis-CNC-Machine-Cheaply-and-/ (http://www.instructables.com/id/How-to-Make-a-Three-Axis-CNC-Machine-Cheaply-and-/)
Title: Re: CNC machines?
Post by: JonHylands on May 28, 2008, 03:24:13 PM
That's a nice machine, and I wouldn't mind even having one, but it won't cut aluminum or brass, just plastic and styrofoam and stuff like that...

- Jon
Title: Re: CNC machines?
Post by: Brandon121233 on May 28, 2008, 08:39:05 PM
Well then, I think you need to evaluate how often you will be making custom parts, and if its not very often I would consider just having a company that specializes in that kind of stuff to make it for you.
Title: Re: CNC machines?
Post by: S. Karim on May 28, 2008, 09:22:18 PM
Well then, I think you need to evaluate how often you will be making custom parts, and if its not very often I would consider just having a company that specializes in that kind of stuff to make it for you.
I'm going to be machining every day, I have lots of projects I cant move on with because they require some sort of custom framing/bracket building. Well I can make them but not at the quality I'm looking for.

Plus companies charge heaps of money.
Title: Re: CNC machines?
Post by: JonHylands on May 29, 2008, 06:26:08 AM
I would strongly advise you look into getting a manual milling machine. You need to learn how to machine with a mill before you advance to CNC anyways. The computer control doesn't negate that fact that you really have to know how to machine material.

This is what I consider about a minimal starting machine:

http://www.sherlinedirect.com/index.cfm?fuseaction=product.display&Product_ID=34 (http://www.sherlinedirect.com/index.cfm?fuseaction=product.display&Product_ID=34)

Unfortunately, its double your budget...

- Jon
Title: Re: CNC machines?
Post by: Brandon121233 on May 29, 2008, 01:09:29 PM
I'd go with a Smithy before a shreline
Title: Re: CNC machines?
Post by: JonHylands on May 29, 2008, 03:21:11 PM
I'd go with a Smithy before a shreline

Sure, if you've got the budget. The original poster clearly doesn't. I just checked Smithy's website, and their cheapest mill is almost $2000, and as near as I can tell, comes with no accessories.

The $1020 Sherline above, can be plugged in and used directly, with no additional accessories required. It has everything you need to do basic machining work for hobby-style robots.

- Jon
Title: Re: CNC machines?
Post by: Brandon121233 on May 29, 2008, 04:00:11 PM
Smithy's website just has list prices, if you get the Smithy Mail out theres always a constant sale, and you can get the baseline Midas 1220 with full accessories pack for $1000 and like $150 in shipping
Title: Re: CNC machines?
Post by: S. Karim on May 29, 2008, 04:36:09 PM
I would strongly advise you look into getting a manual milling machine. You need to learn how to machine with a mill before you advance to CNC anyways. The computer control doesn't negate that fact that you really have to know how to machine material.

This is what I consider about a minimal starting machine:

http://www.sherlinedirect.com/index.cfm?fuseaction=product.display&Product_ID=34 (http://www.sherlinedirect.com/index.cfm?fuseaction=product.display&Product_ID=34)

Unfortunately, its double your budget...

- Jon

Yea but if I buy a CNC Sherline (most recommended the 5400) I can choose to manually mill anytime I want with the handwheels. I plan to manually mill first and when Im ready to CNC, I dont have to buy anything more I can just hook my computer up. Few dollars cheaper if I buy it all at once too.

Manual milling will be annoying and not precise for what I want to do. I need numerous copies of the same parts and I plan to improve parts to create their next-gen, based ob their previous cad design.
Title: Re: CNC machines?
Post by: bukowski on May 29, 2008, 08:42:46 PM
Quote
Manual milling will be annoying and not precise for what I want to do.
Tell that to the guys that work in our shop!  ;)

Check this out: (Admin posted it a while back)
http://techshop.ws/locations.html (http://techshop.ws/locations.html)

There needs to be more places like this!!
Ive honestly been considering joining when the L.A. facility opens up. $1100 bucks a year sounds like a lot, especially for starving students like me, but the access to the metal working equipment alone is priceless (let alone the 3d printer)
Title: Re: CNC machines?
Post by: Admin on May 30, 2008, 07:27:05 PM
How thick of aluminum are we talking about?

I suggest either a bandsaw or scrollsaw, unless you require high precision cuts.
Title: Re: CNC machines?
Post by: S. Karim on June 01, 2008, 03:25:13 PM
Not thick at all, sheet metal style. Max thickness maybe 1/2".
Title: Re: CNC machines?
Post by: Admin on June 01, 2008, 04:24:55 PM
Whoa 1/2" steel!!! That'll take forever!

Perhaps 1/2" aluminum blocks, you mean?
Title: Re: CNC machines?
Post by: S. Karim on June 04, 2008, 07:21:29 PM
Quote
Max thickness will probably be 3/8". Aluminum, brass, or maybe other materials like HDPE and Lexan.
Like said previously, aluminum, brass or plastics. Sheet metal style (meaning 1/8" or whatevers really thin that I find in stores).

1/2" is a possibility, but I highly doubt I'll do things like that. And who said anything about steel :o?
Title: Re: CNC machines?
Post by: JonHylands on June 05, 2008, 08:34:44 AM
Sheet metal is typically 1/32" thick at most, and is (unless you specify otherwise) steel.

Any kind of 1/2" thick metal will require a machine at least as rigid as a Sherline, and even with that you would have to do probably 2 passes on aluminum or brass to cut it, unless you are just shaping one edge.

- Jon
Title: Re: CNC machines?
Post by: pomprocker on June 05, 2008, 04:45:32 PM
CNC Robotics

Build Your Own Workshop Bot

http://books.google.com/books?id=h5NMFGZG6gMC&dq=cnc+robotics&pg=PP1&ots=AKU04eI0Ii&sig=WvKNIRaMcU2cA2lO_a7KCWvRUmo&hl=en&prev=http://www.google.com/search%3Fhl%3Den%26q%3Dcnc%2Brobotics%26btnG%3DGoogle%2BSearch&sa=X&oi=print&ct=title&cad=one-book-with-thumbnail (http://books.google.com/books?id=h5NMFGZG6gMC&dq=cnc+robotics&pg=PP1&ots=AKU04eI0Ii&sig=WvKNIRaMcU2cA2lO_a7KCWvRUmo&hl=en&prev=http://www.google.com/search%3Fhl%3Den%26q%3Dcnc%2Brobotics%26btnG%3DGoogle%2BSearch&sa=X&oi=print&ct=title&cad=one-book-with-thumbnail)


Title: Re: CNC machines?
Post by: S. Karim on June 11, 2008, 05:03:30 PM
Sheet metal is typically 1/32" thick at most, and is (unless you specify otherwise) steel.

Any kind of 1/2" thick metal will require a machine at least as rigid as a Sherline, and even with that you would have to do probably 2 passes on aluminum or brass to cut it, unless you are just shaping one edge.

- Jon

Okay, then 1/32" aluminum it is. And I plan to get a Sherline.