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Using Open Source and CNC? 50

Posted by Cliff from the cumputing-meets-shop-class dept.
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?"
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Using Open Source and CNC? More

Using Open Source and CNC?

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  • 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 (Score:3, Informative)

    by the_illuminatus ( 205461 ) on Friday November 04, 2005 @11:31PM (#13955690) Homepage Journal
    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 [webersys.com]

  • Build Your Own (Score:4, Informative)

    by MBCook ( 132727 ) <foobarsoft@foobarsoft.com> on Friday November 04, 2005 @11:34PM (#13955701) Homepage
    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 [crankorgan.com] 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 (Score:3, Interesting)

      by MBCook ( 132727 )
      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.

    • 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.
      • " 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
        • 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.

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

      • Re:Build Your Own (Score:5, Informative)

        by Phronesis ( 175966 ) on Saturday November 05, 2005 @12:20AM (#13955900)
        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.

  • heh. (Score:2, Funny)

    by grub ( 11606 )

    "No, seriously honey, that RealDoll is my CNC's version of Hello, World!"
    • 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.
  • 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 (Score:5, Interesting)

      by QuantumG ( 50515 ) <qg@biodome.org> on Friday November 04, 2005 @11:48PM (#13955766) Homepage Journal
      If you are going to invest that much, why worry about the cost of software?

      How about worrying about your freedom?
    • 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 price
    • From the link given for CNC, their packages include some form of software.

    • 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 progr

  • 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

  • BRL-CAD? (Score:5, Informative)

    by LWATCDR ( 28044 ) on Saturday November 05, 2005 @12:55AM (#13956048) Homepage Journal
    http://brlcad.org/ [brlcad.org]
    I don't know if it will export IGES but it might. If not Turbocad is pretty cheap.

  • http://www.linuxcnc.org/ (Score:4, Informative)

    by RGRistroph ( 86936 ) <rgristroph@gmail.com> on Saturday November 05, 2005 @02:11AM (#13956278) Homepage
    Not for designing the parts, but for controlling the machine during the run:

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

  • AutoCAD (Score:3, Funny)

    by Kawahee ( 901497 ) on Saturday November 05, 2005 @04:20AM (#13956594) Homepage Journal
    Last time I checked, AutoCAD was free for Bittorrent users.

  • GPL CAD/CAM (Score:2, Informative)

    by Donat ( 8486 )
    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 [ribbonsoft.com]
    (no affiliation)

    • 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 [ribbonsoft.com]
      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
  • 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 (Score:2, Informative)

    by peu ( 163472 )
    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 [dakeng.com]).

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

    And my last recommendation, goto: cnczone.c
  • 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 [tech-edv.co.at]

  • I have the perfect solution! (Score:3, Informative)

    by iq in binary ( 305246 ) <iq_in_binary@hRASPotmail.com minus berry> on Saturday November 05, 2005 @04:30PM (#13958973) Homepage
    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?

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