Replace change gears with a stepper?

Some time ago there was an extensive series called Building the stepper head lathe in Model engineers workshop magazine.
The instructions seemed to be very thorough although I didnt read all of them as the project was well out of my comfort zone.
It may be of some help.
 
My project to drive the leadscrew of my G4000 with a stepper motor is complete. It's been a work in progress for several months.

The features are:
- measures the spindle RPM then computes the proper stepper speed for the selected feed rate
- feed rates from 1 thou/Turn up to 10 thou/Turn
- forward and reverse
- tachometer
- micro-adjustable electronic stop (after stopping, the leadscrew reverses 1/2 turn to relieve pressure on feed lever)
- generic 1602 LCD display (2 lines of 16 characters) with I2C 2-wire interface

This version is not intended for threading. That's the next challenge.

The microprocessor is an Arduino Nano. This little gem doesn't even break into a sweat when calculating the acceleration profiles in real time (in floating point). I'm only using about 1/3 of the Flash so there's plenty of room for more features. Best of all the Nano cost about $3.50. I can't say enough good things about the Arduino platform. The code is written in C++ and their development environment is pretty good.

It was an interesting exercise to research the stepper acceleration. I found a paper from 2005 by David Austin that worked like a charm in this application. With Mr. Austin's equations, the stepper can achieve about 1600 RPM even though it only needs 1100 RPM at the max feed rate and max spindle speed.

Attached are a few photos of the setup.

I'll be happy to share the schematics and the software if there is any interest.

102_4617.JPG
Overall picture of the system. The cover is off of the power supply.

102_4616.JPG
Close up of the stepper and coupler.

102_4615.JPG
Closeup of the tachometer sensor. Note that the gear train is disconnected.

102_4614.JPG
Front panel of the controller

102_4611.JPG
Arduino Nano with all the wiring.

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Micro-adjustable stop sensor

Glen Zoerner
Spicewood, TX
 
Very nice! Am I correct that it is for feed, not threading? I think that would work for me, just use the gears for threading and the stepper for feed. I love the idea of doing it all electronically, but I have a few problems to solve before I feel like attempting it.
 
This looks great. I’ll likely do something similar with my G0602. I’d like to look at your code if you can put it somewhere accessible.
 
ttabbal said:
Very nice! Am I correct that it is for feed, not threading? I think that would work for me, just use the gears for threading and the stepper for feed. I love the idea of doing it all electronically, but I have a few problems to solve before I feel like attempting it.
Click to expand...
ttabbal, yes, it's just for feeding. I've started working on a threading version. There's a lot to do to make that work.
 
And here it is ELS II:


Does anyone know what bottle that is to spray the oil? Looks like a slick way to do it, oil in the can, pressurize the can, long tip to oil on the spot.
 
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