ELS Project - spindle position read-out

[Wheat.Millington]

I'm a complete beginner machinist - I've wanted to learn home machining for some time, so finally bought myself an import lathe. Because it doesnt have a quick change gearbox I decided before buying it I wanted to do Clough42's electronic lead screw. I've done the board, encoder and display, but waiting on my bank balance to recover before getting a stepper/controller/power supply. So in the mean time I dug into the code and set up an option to show me the absolute spindle position. I don't know how much utility this really has, but it was a fun little project.

One thing I haven't figured out is a spindle brake, which would increase the usefulness of this set up. However for basic jobs, as shown, it's enough on my lathe to stick it in low gear to hold the spindle steady-ish.

 

[GunsOfNavarone]

I have a g0602 with Clough's ELS. When you say "spindle brake", are you referring to the resistor braking of VFD or a mechanical brake?

 

[brino]

Interesting and complicated first project.

Welcome to the group!

-brino

 

[Wheat.Millington]

I have a g0602 with Clough's ELS. When you say "spindle brake", are you referring to the resistor braking of VFD or a mechanical brake?

My lathe doesn't have a VFD, it uses a mechanical gearbox. There is no braking system on my lathe at all, but it takes pretty reasonable pressure to move the spindle by hand in the lowest gear (90rpm). I'd like to implement some kind of mechanical brake directly on the spindle at some stage.

 

[RJSakowski]

The spindle position would be useful for CNC type functions. You have already committed to the Clough42 system but another approach would be to know the position of the spindle relative to the carriage position. As I understand it, Clough's approach is to keep track of the encoder counts from the beginning and sends appropriate pulses to the stepper motor to keep in sync. This requires a fair amount processing power. to handle all the calculations in real time.

Aside from that, I'm not sure what advantage would be gained by knowing the spindle position.

 

[Wheat.Millington]

The spindle position would be useful for CNC type functions. You have already committed to the Clough42 system but another approach would be to know the position of the spindle relative to the carriage position. As I understand it, Clough's approach is to keep track of the encoder counts from the beginning and sends appropriate pulses to the stepper motor to keep in sync. This requires a fair amount processing power. to handle all the calculations in real time.

Aside from that, I'm not sure what advantage would be gained by knowing the spindle position.

It's more of an experiement/familiarisation project than anything particularly useful, but like I showed you can do thinks like index markings without additional hardware. I'm really not sure what else it would be useful for. Maybe nothing, to be honest. Fun though.

I should mention that I've already decided to add an additional Clough42 board to my set up for a separate control box, and I'll add some additional features. For example I'd like to add soft stops, jogging, maybe the ability to automatically thread (advance, pause, retract, repeat). I'm a beginner machinist and the most amateur of coders, so it's fun for me to learn this stuff. I've never had the opportunity to do any coding that had real-world (physical) results so this is fun to me.

Addition of a second Clough42 board would also give me access to a a second encoder input and stepper output, so may consider another axis of control, not too sure.

 

[jeffkash]

Buddy and I are doing something similar. He for his Grizzly Gunsmith lathe and me for my LMS 8.5x20. We have added a 2nd Clough board and are controlling the x axis. Intending on automating turning, threading, and tapering. Added a 7" Nextion display for the HMI.

 

[xr650rRider]

I can see the advantage. Doing exactly what you show, making index marks on parts, indexing a rifle barrel, using a drill motor in toolpost and marking/drilling around a part. Good idea.

You sharing code?

 

[jeffkash]

I can see the advantage. Doing exactly what you show, making index marks on parts, indexing a rifle barrel, using a drill motor in toolpost and marking/drilling around a part. Good idea.

You sharing code?

Our focus is in automating functions, so spindle position is incidental to what we are doing. Our code is very much a work in progress and we were not planning on making it available as we don't want to be responsible for supporting it. We are retired programmers and know what support entails. That said, at some point we will describe what we did and how we did it.

 

[xr650rRider]

I was actually addressing the original poster, I'm only interested in the spindle position readout.