Using Open Source and CNC?

blueZ3 asks: "I am thinking about purchasing a CNC (Computer Numerically Controlled) milling machine to build small parts to support my hobbies. I'm looking at a machine from Tormach or CNC Masters. These are small, hobby-class CNC mills. Even though I've picked low-cost machines that look interesting, they all require software that adds significantly to the cost of the machine. I've worked with proprietary CAD software before (TurboCAD, AutoCAD) so drawing parts isn't a big deal. But I'd like to avoid spending huge amounts of money on software, when I'm already breaking the bank for the mill. Does anyone out there have experience using Open Source software for CAD that has a relatively 'normal' GUI/interface? Is there a 'mature' CAM conversion software for same? Does anyone want to comment on the intersection of Open Source and CNC?"

Comments

The department name scares me on this one

[antifoidulus]

from the cumputing-meets-shop-class dept.

Um, I think I will keep my "cumputing" as far away from the milling machine as possible....

At least you can save the price of the OS

[the_illuminatus]

Weber Systems makes a cad/cam package that runs on Linux. In fact, their windows versions use cygwin! Some of the system is written in bash, and you can at least try it out for a while. http://www.webersys.com/linuxsynergy.htm

Re:At least you can save the price of the OS

[Directrix1]

Has anybody checked out the open source BRL-CAD before? Apparently its pretty mature, and the military uses it.

Re:At least you can save the price of the OS

[MrResistor]

I've checked it out, even got it running... I think. Actually using it, well, I can't really say I've done that. Lets just say it's less intuitive then Blender.

Build Your Own

[MBCook]

If you have some tools, you can build your own quite cheap and make a great machine. A guy named John C. Kleinbauer sells plans on his website for a couple of different machines. Once you buy plans, you get access to his "inner circle" BBS (can't remember the name) where he personally supports his plans, he and other members talk about their machines, what they are building, tips, etc.

It's a great little community.

By going this way you can save cash on the machine to buy the software, but they also mention software you can use that is either cheap or free.

Re:Build Your Own

[MBCook]

OK, I just realized that I totally misread your question. I don't remember there being any open source software in the GPL sense, but I think there was some that would give you the source with purchase. That said, if you can't find any, you can always build your own.

I don't know of any specifically. But the only part you'd really need to make would be something to turn 3D models (which you could always make in Blender or some such) into the G-Code file to feed the machine.

Re:Build Your Own

[Gothmolly]

The point of CNC machining is precision down to the tenth or half-tenth thousand. It is not enough to buy a subscription to Make magazine, go to Home Depot, and buy some parts.
The guy is doing it right - buy a real machine, if you expect anything out of it.
He'll still have his software problem, but only one problem, and even thats fixable by money. By building his own CNC machine, he'll end up with both a software AND a hardware problem.

Re:Build Your Own

[HotNeedleOfInquiry]

" The point of CNC machining is precision down to the tenth or half-tenth thousand."

Um, no. The point of CNC machining is to turn out parts cheaper than it can be done by hand. Vast quantities of CNC'ed parts are *not* accurate to a tenth. Often times +/-.001 to .003 is perfectly acceptable and is typical for a production CNC system. Getting closer tolerances than that are usually achieved by honing or lapping.

Specifying overly tight tolerances results in overly expensive parts and assembly problems.

Re:Build Your Own

[Phronesis]

The point of CNC machining is precision down to the tenth or half-tenth thousand.

That's just not true. I do a lot of CNC at 0.005" or coarser tolerances. CNC is also great for turning out lots of repetitive work (drilling and tapping thousands of holes for optical breadboards, turning out dozens of widgets). CNC is also good for complex curves. On the other hand, if I'm machinging rectalinear or circular surfaces and want 0.00001" tolerances, I can do as well by hand with a good solid machine. That way, I can set up compound slides to give me good precision and measure between each cut.

Just because some CNC machines are good for some high-precision work doesn't mean either that CNC is the best way to do any precision job or that CNC is only valuable for doing precision work. CNC can be hugely useful for some loose-tolerance work and some high-tolerance work is better done manually. It's often a question of whether it's faster to create and check the routing code or to cut manually.

Re:Build Your Own

[BrokenHalo]

The point of CNC machining is to turn out parts cheaper than it can be done by hand.

Correct.

Which is why, given that the original poster says he wants the machine for making small parts for his hobbies, he might be getter served by spending his money on a better quality manual machine. He will probably find it more flexible, and he will be able to use any change to buy a good range of accessories.

Re:Build Your Own

[littlerubberfeet]

There is also a certain art to hand-machined parts. I did my first project at age 9 on a Smithy lathe and milling machine with my grandfather. It is like cutting film on a Steinbeck flatbed, not the most efficient way, but with limits that bring out better results sometimes.

As to things being cheaper, my uncle is a professional machinist. He does mainly one-offs for specialized agricultural equipment, and makes the occasional 10 bhp steam engine. He has both CNC and manual machines, and often uses goes with the manual option because it is just plain faster.

I don't know what this hobbyist is doing, but if it is lower precision work with simple parts, even simple threading, he should go with a manual lathe...

Re:Build Your Own

[TFGeditor]

It largely depends on what you are making. Ever tried cutting a perfect (well, as close to perfect as you can get) with a manual machine? And kind of curve is MUCH easier and more precise with a programmable machine, and results are 100 percent repeatable.

Re:Build Your Own

[TFGeditor]

Doh! That should be perfect CIRCLE. Stupid SUBMIT button.

Anyway, same is true for cutting anything other than straight lines. e.g. a hypotenuse or any other angled cuts.

Re:Build Your Own

[Gothmolly]

You're right, my bad. I'm used to the aircraft industry.

Re:Build Your Own

[ivan256]

Ever tried cutting a perfect [circle] (well, as close to perfect as you can get) with a manual machine?

Yup. It's easy if you use the right tool. In the case of a circle, you want a lathe, or a fourth axis in the form of a turntable.

For complex curves though, you're right. CNC is the way to go unless you have some specialty machine. Personally, I've always wanted an eliptical lathe. I'm not sure what I'd use it for; probably only one or two odd jobs over the course of the next few decades. But they're cool, thus I want one.

Re:Build Your Own

[Nutria]

Ever tried cutting a perfect (well, as close to perfect as you can get) with a manual machine?

People were cutting perfect circles for 100 years before CNC machines became available. It and straight lines are probably the simplest things to cut.

Re:Build Your Own

[TFGeditor]

Well, if you can cut anything resembling a circle using a 2-axis, hand-operated milling table, all I can say is you are one helluva better machinist than I am.

Re:Build Your Own

[Nutria]

No, not free-hand, of course not. Pardon if that's what I implied.

Re:Build Your Own

[John Harrison]

You're using the wrong tool for the job. Try a lathe.

Re:Build Your Own

[Mysticalfruit]

A buddy of mine has a machine made by TAIG www.taigtools.com and the thing is amazing. He initally bought the hand version and then for a couple hundred bucks more bought the add on motors to make it CNC.

All told I think he's spent about 3 grand (over several years, so it's not that bad).

The only short coming he's had with it is that it's a small mill, so your not going to milling yourself a 430 Chevy big block with it...

heh.

[grub]

"No, seriously honey, that RealDoll is my CNC's version of Hello, World!"

Re:heh.

[NoMoreNicksLeft]

Realdoll requires sculpting a pleasant feminine shape, and building a cast to pour the silicone into. Much more art and chemistry than CNC or machining.

Just buy the software

[bshellenberg]

I don't understand why you would pay thousands (or tens of thousands) of dollars on a machine, but you won't pay a measly $400 for the software? That just doesn't make any sense. If you are going to invest that much, why worry about the cost of software?

Re:Just buy the software

[QuantumG]

If you are going to invest that much, why worry about the cost of software?

How about worrying about your freedom?

Re:Just buy the software

[Jeff DeMaagd]

In one sense, I agree, in another, I can see the benefit in this case. Normally, I'd say commercial if you need the features, but this is a somewhat different situation.

For one, a hobbyist might see a novel need or use that a corporation would overlook. A hobbyist can extend the code or add compatibility. A hobbyist might want to design a custom cutting machine and need custom software to operate it. There is some extensible and modifiable commercial stuff out there, but that is often designed and priced for the commercial market. A hobbyist might want to retrofit an old machine with software and electronics to their liking. The cost of software is just a tiny portion of the potential.

But I do see the value of just buying software. I wanted to make some CNC software but on careful examination and a little bit of preliminary pseudo-coding, I found the task ahead to be daunting. I never did make the machines I wanted to make, and the lack of an open software system was one reason I chose not to continue. Maybe someday if is a group CNC hobbyists are willing to work together on such a project, I'd be willing to lend a hand.

Re:Just buy the software

[Anonymous Coward]

I don't understand why you would pay thousands (or tens of thousands) of dollars on a machine, but you won't pay a measly $400 for the software?

"I don't understand why you would pay $300,000 for a house but you won't pay a measly $1000 for a sofa".

"I don't understand why you would pay $10,000 for a car but you won't pay a measly $2000 for a stereo system".

What's to understand? Just because he paid a lot of money for a related item, it doesn't mean he feels like throwing money around for the sake of it.

Re:Just buy the software

[Anonymous Coward]

Freedom in the CAD industry? LOL! Not only is it the most complex problem domain in software, there's patents, too! ROFL!!! Have you ever seen a good FOSS CAD program? NO? Of course not! No one, absolutely no one, has the resources to reproduce Pro/E, CATIA, etc. as a FOSS project. These software make GNOME look like a piece of dust next to a mountain.

Re:Just buy the software

[QuantumG]

I bet it's not nearly as hard as they like to think it is. Software made by electrical engineers is always a heck of a lot more complex than it needs to be. I don't even wanna think about software made by mechanical engineers.

Re:Just buy the software

[Anonymous Coward]

...aaaand you fail the SATs, once again. You really need to work on analogy before you get out of high school.

Try again!

Re:Just buy the software

[Anonymous Coward]

I'm not dead sure what that's supposed to mean, but I think possibly you're an asshole.

Re:Just buy the software

[bhiestand]

I don't understand why you would pay thousands (or tens of thousands) of dollars on a machine, but you won't pay a measly $400 for the software? That just doesn't make any sense. If you are going to invest that much, why worry about the cost of software?

$400 for GOOD CAD/CAM software? Show me now. I'll buy ten copies to start with. MasterCAM costs well into the 5-digit range, and it's worth every penny, at least when one workstation with about $20,000 of hardware/software can do all the design and programming for $1,000,000/year (US) in production.

Re:Just buy the software

[The Clockwork Troll]

No offense, but if your magnum opus is a 200-line MFC app that pretties up "netstat", I am not sure you are qualified to judge what's "hard". Actually, I'm sure you're not.

I've been wishing

[dtfinch]

I've had no luck finding good open source CNC/manufacturing oriented 3D CAD/CAM software. There are some on sourceforge, but many of the commercial programs are a whole lot better. You might be able to piece something together out of many smaller programs, like one program for creating the models and another to convert models into G-code, or whatever else your specific CNC machines might accept. I'm not an engineer of the non-software kind, and I don't use CAD programs, but I work around people who do, and damn, some of that software is expensive, so we've always been interested in open source alternatives.

Re:I've been wishing

[Anonymous Coward]

The reason there isn't good free CAD software is that it has to be mathematically perfect in tons of areas of detail. This isn't like someone writing a free UNIX kernel...it's about PHD level mathematics, PHD level engineering, and PHD level physics all under one banner. Lots of people have invested their whole lives into this technology.

In a few decades, perhaps it'll become commodity level tech like operating system kernels or office suites...maybe.

CNC mills includes software

[jhines]

From the link given for CNC, their packages include some form of software.

BRL-CAD?

[LWATCDR]

http://brlcad.org/
I don't know if it will export IGES but it might. If not Turbocad is pretty cheap.

http://www.linuxcnc.org/

[RGRistroph]

Not for designing the parts, but for controlling the machine during the run:

http://www.linuxcnc.org/

http://www.opencascade.org/

[ghinckley68]

http://www.opencascade.org/ should do all you need open source. Has some rather high system requirments but it seems to be a good program.

Ugh.. CNC "standards"

[zippity8]

Having worked with a few machines in my time, I have found it surprisingly irritating how unique each control acts. Although they all respond to G codes, many of the machines that I've worked with require slightly different codes for different applications. And it's not just formatting, certain codes have different parameters as well. Not to mention that each machine can get finicky when invalid data is passed in.

I would be truly surprised if someone went through the effort of covering all types of controls. On the other hand, you might luck out and find that most personal milling machines use the same control. I haven't touched any machines smaller than an average american SUV, so I'm not exactly speaking from experience here.

AutoCAD

[Kawahee]

Last time I checked, AutoCAD was free for Bittorrent users.

GPL CAD/CAM

[Donat]

I have been doing CNC work for a few years now, mostly freelance. Drawing tool paths for business signs, reproducing parts for farm equipment, some wood craft items and writing software to do the simple stuff; generating and post processing g-code and talking to controllers.
You might want to check out QCad, it is GPL'd CAD/CAM software with g-code support and it only costs a few hundred dollars.
http://www.ribbonsoft.com/qcad.html
(no affiliation)

Re:GPL CAD/CAM

[Kevin Burtch]

I don't know about pricing... maybe that's for support, as qcad is GPLed.

$ rpm -qi qcad (edited to get around slashdot's lame lameness filter)
Name : qcad
Version : 2.0.4.0
Build Host: extras64.linux.duke.edu
Source RPM: qcad-2.0.4.0-2.src.rpm
License: GPL
URL : http://www.ribbonsoft.com/qcad.html
Summary : A simple 2D CAD program
Description :
QCad is an application for computer aided drafting in two
dimensions. With QCad you can create technical drawings such as plans
for buildings, interiors or mechanical parts. QCad works under Linux,
Unix Systems, Mac OS X and Windows. The source code of QCad is
released under the GPL (Open Source).

Write your own

[TFGeditor]

I have a small 3-axis machine that I bought 20-plus years ago that came without software. I wrote my own control program(s) in C-BASIC. It works great (still have/use it) and does anything I need. If I have a need the existing software cannot accomodate, I just write a custom program to handle it.

Options

[peu]

For the numeric control part of your CNC machine you can use the EMC (linuxcnc.com) which is opensource, or you can use Mach3 (artofcnc.com) wich is the paid and much improved version of it for a mere $150, you will receive in support many, MANY times that amount in the 1st months.

Regarding CAM, there are simple converters from vector art to G-Code such as ACE Converter (http://www.dakeng.com/ace.html).

For CAD you got the ad supported version of alibre (alibre.com)

And my last recommendation, goto: cnczone.com and read for hours, there are tons of knowledge there on every aspect of CNC.

BTW, if you are on a short budget, why not build the machine yourself and save some money for an entry level CAM app?

Re:Options

[Anonymous Coward]

Mach is NOT a "paid and much improved version" of EMC. Both had their roots in software created at NIST... that is all the similarity there is. Mach will not run on linux; neither is it hard real-time. It supports lathes (especially threading) where EMC does not, yet. EMC runs on linux using the hard real-time extension/kernel patch RTAI. It can handle non-trivial kinematics (i.e. hexapod/stewart platform, scara, etc.) EMC2 includes a software PLC to handle "special" functions like tool changes, part changes, etc.

Found after googling for a couple of minutes

[stefaanh]

open source CAD program linux

I think the links listed here to linux installable CAD oriënted development projects is worth following.
http://www.tech-edv.co.at/lunix/CADlinks.html

I have the perfect solution!

[iq in binary]

YOU are a cad/cam program my friend. CNC machines are controlled by a universal machine programming language called G/M code.

It's also probably the simplest script language known to man. Learn how to use it yourself instead of spending several thousand dollars on a CAD/CAM program.

Here's an example of your typical part program for a CNC machine:

G72G81G90G91

G0T1M06

S1200M03

X0Y0Z.1M08

G83X0Z.5Z.1Z.1

G0Z3.0

G0M22

That program just drilled a hole .4 inches deep into the center of a circular part. Fairly simple, neh?

Re:I have the perfect solution!

[Degrees]

And interestingly enough, that language isn't very different from Scalable Vector Graphics (SVG) - although SVG is 'defined' for 2D, with the 3D extensions still in 'experimental' form (last I checked).

BricsCAD / IntelliCAD

[Anonymous Coward]

Does anyone out there have experience using Open Source software for CAD that has a relatively 'normal' GUI/interface?

It's not open-source but it's cheap: Try BricsCAD http://www.bricscad.com/ or IntelliCAD.
These are AutoCAD clones at one-twentieth the price and relatively similar GUI.