Group Actions
Engagement
  • Author Author: Former Member
  • Date Created: Date Created
  • Views 538 views
  • Likes 0 likes
  • Comments 2 comments
Related
Recommended

CNC Mill / 3D Printer for small objects

Former Member

I am Building a small device that will work as both a CNC mill and a 3D printer.

I have decided to construct it out of some aluminium and steel pieces I already have, to keep the expense at a minimum.

I am still mainly in the design phase, but I have tried some mechanical combinations to check what is feasible.

Here in this Youtube video I have connected 1 axis to a Raspberry Pi so I can check the movement in this type of design:

https://www.youtube.com/watch?v=B5X-abcSZno

My comments to this video:

While making my own 3D Printer design, I needed a testbench for the step motors.

I decided to use the adafruit lesson 10 scenario and a L293D IC to drive the NEMA17 2,5A step motor.

http://learn.adafruit.com/adafruits-raspberry-pi-lesson-10-stepper-motors

Unfortunately the L293D only tolerates 0.6A, so I need to throttle the setup down a bit, so this is with 5V as Vs for the output side. That settles the heat dissipation requirement down a notch. I also added (0,0,0,0)'s after every complete movement to 'let go' of the coils. That also helps with the heat problem.

Just to make sure if anybody else tries lesson 10 with a NEMA 17: Raspberry Pi can NOT supply the step motor at all (Vs). The motor sinks the overall voltage to a level that just turns the RPi off!

  • in reply to Former Member

    Hi Jay Gill,

    Thanks for the post. Are you sure I can run the extruder and hotend of a 3D printer with TinyG? It looks like I'd need extra circuitry to do that, whereas PrintrBoard has the output ports with high current for the hotend and also for heating the surface, but I'm not sure if PrintrBoard can do CNC milling.

     

    Per

  • Sounds like an interesting problem and it's fun playing with motors.  I've watched a lot of people struggle for a long time to get 3 to 4 coordinated axes working smoothly enough to get the job done.  So I'd suggest looking at one of the driver boards out there.  I'm using https://github.com/synthetos/TinyG/wiki with great success.  It's very easy to use takes G-Code in via USB serial, and directly drives the steppers.  I've been using mine to drive a 3 axis CNC for a few years now.  It's also the driver underneath several of the 3D printers currently on the market.  So it will support both of your goals.