CNC controller

Discussion in 'CNC Machines and Conversions' started by ddmckee54, Sep 12, 2019.

Help Support HMEM by donating:

  1. Sep 25, 2019 #21

    barryc

    barryc

    barryc

    Member

    Joined:
    Jul 7, 2010
    Messages:
    7
    Likes Received:
    2
    Location:
    Warwickshire, UK
    Hi all,

    I am using Mach3 quite comfortably on my small CNC rig using Vectric VCarve Pro v10 software which cost £540 ($699). You should know that the Vectric Aspire software that Leonardo mentioned is top of the range at £1500 ($1995). You can obtain the same results with even cheaper Vectric versions, the more expensive just adding extra functions. Just my two pence worth!
     
  2. Sep 25, 2019 #22

    ddmckee54

    ddmckee54

    ddmckee54

    Well-Known Member HMEM Supporter

    Joined:
    Jul 8, 2009
    Messages:
    204
    Likes Received:
    24
    Leonardo:

    I was initially under the impression that the Arduino couldn't handle the curves, I have since revised that idea. I've posted this question on several forums and my understanding now is that the Arduino does indeed do curves, it supports the G02 and G03 commands. I now believe that it was whatever software that was used to generate the g-code that couldn't handle some curves, in particular full circles and poly-lines. I have run into that issue before, and I know some of the work-arounds. The DXF to G-code converter that I was using many years ago had that same issue, couldn't handle circles or poly-lines.

    From of some the examples that I have seen of machining done on Arduino based machines, that option is definitely still on the table. (Always did like it from the price stand-point.) I would probably use the Arduino to provide the Step/Direction/Enable signals to external stepper drives to get drivers capable of higher current. I think NEMA 23 motors would be pushing the envelope for an Arduino to drive directly just a little too much.

    Don
     
  3. Sep 25, 2019 #23

    awake

    awake

    awake

    Active Member

    Joined:
    Sep 5, 2019
    Messages:
    35
    Likes Received:
    4
    Gender:
    Male
    Occupation:
    Educator
    Location:
    North Carolina
    Yes, you definitely cannot drive a stepper motor directly from any microcontroller. The ultra-cheap "Polulo" drivers can deliver 1 or maybe as much as 1.5 amps with sufficient air flow, but for NEMA 23 motors you would probably want something more like this: https://www.ebay.com/itm/TB6600-Dri...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

    No affiliation, and to be honest, I haven't tried it ... yet. I've got three of those TB6600 modules that I am planning to hook up to an Arduino Nano for a GRBL based CNC. But as best I understand it, the Arduino can connect directly to the step and direction inputs on the TB6600, and it will drive the motors using the micro-stepping and amperage selected via the switches on the TB6600.
     
  4. Sep 25, 2019 #24

    ddmckee54

    ddmckee54

    ddmckee54

    Well-Known Member HMEM Supporter

    Joined:
    Jul 8, 2009
    Messages:
    204
    Likes Received:
    24
    I think I've got something like those squirreled away someplace, enough for 3 motors anyway. (Bought them a few years ago.)

    I kept losing steps on one axis of my 3-axis Stepperworld driver that I had used for years. Never got around to installing them, too many other things to do.

    Don
     
  5. Sep 30, 2019 #25

    Leonardo

    Leonardo

    Leonardo

    Member

    Joined:
    Aug 11, 2013
    Messages:
    8
    Likes Received:
    1
    Hi Don and all!

    I decided to share my controller board to help the people interesting in using Arduino and GRBL to control your CNC machines.

    I developed this board because I do not like the CNC shield commercially available for the Arduino UNO.
    My board has all input and output isolated with optocouplers and noise blocked / reduced by ferrite beads.
    Although the Omron 61A1 are a bit expensive they are really excellent and very reliable components and I like them very much (actually they are solid state micro relays).

    Regarding the motor drivers, although I have great respect for Pololu, I do not trust in the Chinese knock off versions and, at the time of buying you do not know what actually you are buying.
    Instead of that I prefer to use bigger drivers as the TB6600 and the kind. An important note on the driver is that the Pololu type do not let you control the stand by current of the motors. This problem is solved using the TB6600 drivers so your motors will work much cooler and safer.

    By the way, I would like to say some more about the Pololu drivers. They are a smart piece of engineering. They designed the tiny board in multilayers with the proper copper thickness and a lot of metalized through holes in a way that the total copper area will suffice to sink the heat of the microchip. That is great and they achieve a very small stepper motor driver that you can place almost anywhere. I think that this driver is a good option when you are working in small sized projects. Only problem I can see is that you cannot control the holding current when the motor is stop.

    I am posting here some pictures of my machine showing my controller board, the TB6600 drivers and the NEMA 23 stepper motors. I use Oriental Motor PKP268U

    Well, that is all by now. Hope you like the board!

    DBL_CNC_Cableado_1.jpg

    DBL_CNC_Cableado_2.jpg

    DBL_CNC_Cableado_3.jpg
     

    Attached Files:

  6. Sep 30, 2019 #26

    Leonardo

    Leonardo

    Leonardo

    Member

    Joined:
    Aug 11, 2013
    Messages:
    8
    Likes Received:
    1
    I forgot to mention that the board is a single layer and you need a 0.2/0.25 mm 30º conical cutter to make your board using the DWG file I uploaded.

    Finally I must say that this board design is shared as is and it is at your own risk to decide to use it. I also will not give support to this project. You have all the info about how to upload GRBL V1.1f to your Arduino, configuration, commands and so on in the GRBL GitHub site and, fortunate you, all the info is write in your native English language. :)

    Note: The GRBL version 1.1h will not work with my board because of the moved pins.

    https://github.com/gnea/grbl

    Hope you enjoy GRBL. It is a great GCode interpreter!

    Leonardo.
     
    Last edited: Oct 1, 2019
  7. Oct 1, 2019 #27

    tjwal

    tjwal

    tjwal

    Well-Known Member

    Joined:
    Sep 22, 2013
    Messages:
    71
    Likes Received:
    6
    I’m not sure of the purpose of the opto-isolators on the outputs. Aren’t the TB6600 modules already opto-isolated?

    For the inputs what is the advantage of the omron chips versus something like a 2n26?

    John

     
  8. Oct 2, 2019 #28

    Leonardo

    Leonardo

    Leonardo

    Member

    Joined:
    Aug 11, 2013
    Messages:
    8
    Likes Received:
    1
    Hi John, you are right. The TB6600 driver has optically isolate inputs so, in this case you could save these optocouplers.
    When I did this board I thought that it would be better to isolate all the inputs and outputs. In this way that it will be possible to use any driver or input signals coming from different kind of components.

    Regarding the 2n26 (perhaps you wanted to say 4N26?) it will work for sure but I prefer to use the same component in the whole board and, as I told before, I like the 61A1 very much. Its output is MOSFET instead a transistor and can handle 500 mA (I know... not needed in an Arduino input!) :)

    Anyway, everything can be improved and I am always open to critics and suggestions. What I can assure you is that this board can run hours and hours in a noise environment without any problem.

    Leonardo
     
  9. Oct 2, 2019 #29

    tjwal

    tjwal

    tjwal

    Well-Known Member

    Joined:
    Sep 22, 2013
    Messages:
    71
    Likes Received:
    6
    Hi Leonardo
    Thanks for the reply. Yes 4n26. I have a handful left over from a project many many years ago.
    John
     
  10. Oct 2, 2019 #30

    Leonardo

    Leonardo

    Leonardo

    Member

    Joined:
    Aug 11, 2013
    Messages:
    8
    Likes Received:
    1
    You are welcome John.
    If you want to use this board but placing the 4N26 you have, you will need to change the tracking a little bit but them will work. Just take care of the polarity of the 4N26's transistor output.
    Leonardo.
     

Share This Page