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  1. #1
    Join Date
    Jan 2006
    Posts
    15

    Building my first CNC machine - Shapeoko

    I joined this site a long time ago when I got interested in CNC machining but I ended up having to focus on things like School and work for the past few years. I just ordered the mechanical kit to build a Shapeoko and I am now waiting for it to be shipped to me (60days ). Honestly it seems like little has changed in the world of DIY CNC machines except for their being a whole lot more people into it now. So now that I have my first machine on the way I could use some help on selecting the electronics for it.

    Here are my plans.

    - Build shapeoko to learn basics of mechanical, electrical and CAD/CAM involved.
    - Build stuff
    - Modify Shapeoko to be a much more useable size or build a second machine.
    - Build more stuff
    - One day have a 4'X8' table machine

    Because I have plans to go larger I think I might want to buy larger stepper motors and a nicer controller. Here are my questions.

    - this machine can handle NEMA 23 motors on the X and Y axis, I was thinking I should get large motors so I could use them later. Weight seems like it would be a limiting factor. Can I use large enough motors to be later used on a much bigger table?

    -If I can't use large enough motors to use on a much bigger table later, are there other benefits to using larger motors? What oz/in should I be looking at?

    - The machine uses a Nema 17 for Z axis but could easily be modded to to work with a NEMA 23 motor, is it worthwhile? Currently I don't think so

    - A lot of the guys are using arduino shields and AtomCNC boards. I was thinking about spending the money on a used Gecko G540. My issue is that I don't have a computer with a parallel port and I don't plan to buy one. I have been told that I can use a DB25 break out board with the G540 and connect to an arduino. Can someone tell me the pros and cons here and if there is some other option I should consider? I don't understand why Gecko would even still be producing anything that works with a port standard as dead as a parallel port. Is there a new product that has replaced it as the standard?

    -is there anything else I should be researching or shopping for?

    -

  2. #2
    Join Date
    Jan 2009
    Posts
    45
    I just ordered one also. I will be using the nema 23 motors on X,Y and Z. I bought a computer off ebay for $50 and a flat panel monitor for $20. I will be using the Hobby CNC 4 axis Pro board.

  3. #3
    Join Date
    Jan 2006
    Posts
    15
    What oz/in are the nema 23 motors you picked?

  4. #4
    Join Date
    Jan 2009
    Posts
    45
    3 PCS NEMA 23 Dual Shaft STEPPER MOTOR 425 OZ-IN Rated at 2.8A | eBay

    They may be a little big for the Shapeoko but I already have them.

  5. #5
    Join Date
    Jan 2006
    Posts
    15
    I was looking at using those same steppers but I am worried about their size and weight. Since you already have them, do you think they will work out ok?

  6. #6
    Join Date
    Jan 2009
    Posts
    45
    I'm worried about the weight they are heavy. I'm going to try them out. If you are going to use Nema 23 you will have to replace the drive pulley's on X and Y and If you use one on the Z you will have to get a new coupler.

    6.35 x 8mm CNC Motor Jaw Shaft Coupler 6.35mm To 8mm Flexible Coupling | eBay

    Pulley, MXL 20 Tooth, 1/4 inch Bore, Dual Flange - $5.500 : MakerSlide Store, Open source CNC

  7. #7
    Join Date
    Mar 2003
    Posts
    35538
    Just a heads up about steppers.
    The 425oz Nema 23's can be a very poor choice, if the application requires higher rpm (over ~500 maybe). They have a high inductance, and to get the best performance from them you need a drive that can supply a bout 80V. Running them on inexpensive drives will result in only about 30% of the performance they are capable of.

    - this machine can handle NEMA 23 motors on the X and Y axis, I was thinking I should get large motors so I could use them later. Weight seems like it would be a limiting factor. Can I use large enough motors to be later used on a much bigger table?
    My recommendation, would be to build it as designed with the smaller steppers, and when you want to upgrade to a large machine, sell this one as a complete, running machine. You should be able to get most of your money back out of it.
    I'm not familiar with the Shapeoko, but I just watched a few video on YouTube. I don't think the larger steppers will be of any benefit, and it really makes no sense to buy steppers for a machine you might build later. Steppers are not very expensive, and as I said, you'll get a good return on your investment should you decide to sell.


    - A lot of the guys are using arduino shields and AtomCNC boards.
    Not here they're not.
    Arduinos running Grbl are popular with the "maker" crowd, but for serious CNC use, they are very limited.

    I was thinking about spending the money on a used Gecko G540. My issue is that I don't have a computer with a parallel port and I don't plan to buy one.
    You should be able to make up a custom cable to connect a G540 to your Arduino. The G540 doesn't specifically need a parallel port. It's just that the most popular control software Mach3 or LinuxCNC) send their step and direction signals through the parallel port.

    Can someone tell me the pros and cons here and if there is some other option I should consider?
    Do you mean comparing an Arduino/AtomCNC combo vs say Mach3 and a G540?

    I really don't have any experience with the Arduino stuff. It's probably fine for starting out with a small machine like that.
    However, if you plan on moving to something bigger later on, it might be a good idea to get used to Mach3 or LinuxCNC right now, rather than relearn all over again later.
    I don't understand why Gecko would even still be producing anything that works with a port standard as dead as a parallel port. Is there a new product that has replaced it as the standard?
    As I said, it's the software that uses the port. The G540 just has a parallel port to make connecting it easy. It doesn't need a parallel port to work.

    There are plenty of other options if you don't want to use a parallel port, but they'll cost a lot more, as you'll be buying hardware motion controllers.

    Fwiw, there are lots of PC's still being made with parallel ports. Intel Atom motherboards have them, and they're inexpensive, and quite popular for CNC use.
    A lot of standard motherboards actually have parallel port headers, but don't have a physical port attached.
    Gerry

    UCCNC 2017 Screenset
    http://www.thecncwoodworker.com/2017.html

    Mach3 2010 Screenset
    http://www.thecncwoodworker.com/2010.html

    JointCAM - CNC Dovetails & Box Joints
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    (Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)

  8. #8
    Join Date
    Jan 2006
    Posts
    15
    Gerry thanks for the help

    I think I will be going with smaller nema 23 steppers on the X and Y. One of the recommended steppers is this guy.
    Phidgets Inc. - 3308_0 - 57BYGHM201 NEMA-23 Bipolar 50mm Stepper

    Considering that the shapeoko is expandable and has been built up to 36"X36" and I might do to same before I build a large table, will this be enough? I don't want a machine that is working on the edge of it's performance for everything it does.

    I don't quite have down the computer to step drive system yet. Is there a good place to read about all the current ways to do this? The parallel port kind of makes sense to me because in a way a CNC machine works like a printer. The G540 is just a prepackaged setup of G250 digital step drivers right? Is the rest just a case and a DB25 breakout that is pre wired? If so does that mean I could use any of their digital step drives and my own db25 or other way of sending signal to them? I think I just need someone to confirm that I am on the right track as I think I am starting to get it.


    I guess my last question is if there is any reason to wait for mach 4 to come out as it seems that mach 3 is near the end of its life.

  9. #9
    Join Date
    Sep 2012
    Posts
    0
    I don't understand why you want to build up the machine. By the time you do so, you've pretty much built a completely new machine anyways. You'd have to get longer lead screws and support shafts, more powerful motors for such a large table, redo the entire chassis of the machine and so on. Why not just sell the Shapeoko once you've gotten your use out of it and purchase/build a better machine?

  10. #10
    Join Date
    Jun 2011
    Posts
    692

    Re: Building my first CNC machine - Shapeoko

    I've scratched my head at the stationary belt design Shapeoko uses as well. If the belt engaged with another that was fastened down to something to act like a rack and pinion drive (like the long thread I think in the mechanical engineering section,) it would make sense as that method reduces belt stretching and ringing. Their method doesn't seem to have any advantage over a normal moving belt drive that I can see.

  11. #11
    Join Date
    Nov 2005
    Posts
    222

    Re: Building my first CNC machine - Shapeoko

    I think I will be going with smaller nema 23 steppers on the X and Y. One of the recommended steppers is this guy.
    Phidgets Inc. - 3308_0 - 57BYGHM201 NEMA-23 Bipolar 50mm Stepper
    Those specs don't look right. It shows 14mH inductance with 24volt recommended voltage. Normally you would calculate the voltage as 32 times the square root of the inductance. So, 32*SQRT(14) = 119.733 volts. I'm running my 2.8mH stepper at 48volt. I could go to 53.5. My steppers barely get warm.

    Also, here is a good article about .9 vs 1.8 degree steppers.

    https://www.linengineering.com/resou...on-0-9-vs-1-8/

    I don't quite have down the computer to step drive system yet. Is there a good place to read about all the current ways to do this? The parallel port kind of makes sense to me because in a way a CNC machine works like a printer. The G540 is just a prepackaged setup of G250 digital step drivers right? Is the rest just a case and a DB25 breakout that is pre wired? If so does that mean I could use any of their digital step drives and my own db25 or other way of sending signal to them? I think I just need someone to confirm that I am on the right track as I think I am starting to get it.
    The G540 is like having all of your drives and BOB (Break Out Board) all in one unit. It will make the wiring easier and cleaner. Visit the Gecko site https://www.geckodrive.com/g540-4-ax...per-drive.html and search this site for "G540"

    I guess my last question is if there is any reason to wait for mach 4 to come out as it seems that mach 3 is near the end of its life.
    I use LinuxCNC. It's free and works great.

  12. #12
    Join Date
    Jun 2011
    Posts
    692

    Re: Building my first CNC machine - Shapeoko

    Quote Originally Posted by rcheli View Post
    Those specs don't look right. It shows 14mH inductance with 24volt recommended voltage. Normally you would calculate the voltage as 32 times the square root of the inductance. So, 32*SQRT(14) = 119.733 volts. I'm running my 2.8mH stepper at 48volt. I could go to 53.5. My steppers barely get warm.
    Spec sheet also shows the max speed at the recommended voltage is only 300 RPM.

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