Electronic Upgrade
I’ve listed some plans to upgrade the electronics on the CNC within the hackspace
Currently we’re using grbl on a 16bit arduino with small Alegro drivers which isn’t ideal
Controller
For the controller board the plan I’ve got at the moment is to instead use a arduino due (32bit) with a breakout board
for the breakout board I’m currently using one of these at home
But what I think I’ll try and do instead of buying one is make a custom board
that as green plugs for the stepper drivers
as that is designed more for pololu and I already have the kicad schematic for it as well.
Stepper drivers
For the stepper drivers there’s currently two options I’m looking into
DM542 / DQ542MA
This is one option, it’s easier to use as it’s a pre-made module
DM542 / DQ542MA seem to be a popular choice on the cnc forums I think
I think they have DSP’s in so are a bit quieter
- http://openbuildspartstore.com/dq542ma-stepper-motor-driver/ 30 x 4
- https://www.amazon.co.uk/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=dm542
- https://www.youtube.com/watch?v=8sHsa4FZ2Cc
- https://www.amazon.co.uk/Kehuashina-Leadshine-DM542-05-DM54205-Stepper/dp/B07BBCWH7X/ref=sr_1_2?ie=UTF8&qid=1528157669&sr=8-2&keywords=dm542
TMC5160
This is the one I’d like to use, possibly sitting on top of another board with a bit of opto isolation
trinamic drivers have some features built in we could use later on such as measuring the amount of torque against the bit
or stealthchop etc, but to start with we could just run them as normal in step / dir mode
however those fet’s are only rated for 2.8A so I’ve asked trinamic if they think the Bob board would be suitable.
Also an additional heatsink may be needed.
Other suggestions
- https://www.buildyourcnc.com/item/electronicsAndMotors-stepper-driver-3!0a
- https://www.youtube.com/watch?v=woyp03D0neY
CNC Cable / Connectors
We’ll need to move the electronics to it’s own seperate box under the bench
- stepper driver cable - ?? not sure how many meters to use yet https://www.cnc4you.co.uk/Electrical/Cables-Connectors/4-Core-Screened-Cable-0.75mm-12Amp
- Connectors - todo check which connectors to use, I think those 4 pin areospace ones
Box
I’m not sure if the box I’ve got so far will be big enough for everything could do with finding something a bit bigger in the space
TODO
Endstops
The current end stop board uses relays, I might try and replace that with an opto-coupler board
Machine kit
later on we may want to look into using a beaglebone board with a cape of some description with machinekit however I need to spend some time testing / figuring that out so for now we’ll stick to g2core since I’ve already got that working before also we need it to work with chillipepr.
Some example cape’s used with machinekit (cramps / optocape):