An Electronic Lead Screw controller using a Teensy 4.1

[jwmelvin]

I would use keyed connectors were this to be commercialized.

Good point about the stepper-driver’s inputs and encoder outputs. Reverse-polarity protected power input seems good even with keyed connectors, and would be easy. I don’t think you need it to be fully industrially hardened, just taking a few steps in the right direction would probably save you headache. Great idea to add some additional inputs and outputs.

 

[jwmelvin]

Take a look at JLCPCB if you haven't already heard of them.

I like the recommendation. I’ve always used OSH Park but just read this: https://hackaday.io/project/159057-game-boards-for-rc2014/log/150971-pcb-manufacturers-compared

 

[devils4ever]

Ditto. I've used Osh Park in the past and have been very pleased.

 

[WobblyHand]

Another forum informed me on JLC. They were cheaper than PCBway by quite a bit. I placed an order with them as well, because the cost for 5 with shipping was around $11.25. However that was with PbHASL. I will use those boards for debug. Any boards that I might ship would be lead free.

 

[WobblyHand]

Tracking down a low speed bug? At low speeds the stepper chatters and does not obey commands. Not sure what causes this. The stepper appears not to move for fine feeds or fine threads and slow spindle speeds. You'd think this would be easy for the stepper, as it has maximum torque then. Have to drag down the oscilloscope to try to figure this out. At normal thread cutting speeds and pitches, all is fine.

 

[WobblyHand]

Power supply was the problem. Previously ran via the PC, now using a wall wart. Wall wart was trashy with lots of noise. Noise caused false triggers at random times. Verified with an oscilloscope. Replaced PS with an Apple cube. Now fine feeds run at 96 RPM up to 890 RPM, which is as high as I can go without changing the belt. All is good again.

 

[WobblyHand]

Going through connector paralysis right now. Finding matching connectors with panel mounts is a royal pain. Tough to find stuff that is compact, inexpensive, in stock, and not obsolete. Anyone know of a supplier for M8 connectors for cables and panel mount? I need 4, 5, 6 and maybe 9 pins. Bonus if they are keyed. I saw the LEMOs, but they are too expensive to use. My goodness, they are nice though.

On the other hand, it is kind of informative watching the progress of the PCB's through production. PCBWay is 73% done whereas JLCPCB is 44% done. PCBWay has little videos showing the steps. Both of them should be shipping early next week. We shall see which is a better board.

 

[WobblyHand]

PCBway shipped my bare boards! Now the wait. Should be here in 2-3 weeks. JLC is still fabricating the second lot, they are about 1/2 way done, maybe more, haven't checked this morning. It's the end of the day there, so some additional progress should have been made.

 

[WobblyHand]

Connectors ordered. Using GX style connectors with a single M8-4 in case I can control the micro stepping. Should be here in mid October. Hope they work out ok. Total order was about $40 for 24 connector pairs. Sure hope I can use them. Otherwise falling back to DB-9's.

 

[jwmelvin]

Sorry if you discussed this, but what is limiting your top speed? (Why do you need to dynamically change microstepping?)

Edit: am I correct that it's to get increased torque from the motor by reducing microstepping where possible? If you aren't close to the top speed, you can use mechanical reduction also?