electronic lead screw

GunsOfNavarone said:
@DoubleHelix what VFD are you using? During my build/install I came across something that I remember thinking I could use for such a thing (ELS wasn't even a thought at that point) I'll have to look that up again & post here. At say 60 RPM, the spindle could be stopped in a second.
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Hitachi WJ200-022SF with a 35ohm 300W braking resistor. 1sec stopping shouldnt be a issue. This is just theory since I have a lot to go before testing (still dont have 220V in the garage yet).
 
@GunsOfNavarone Just saw you were in Lakewood. I'm sure at the pace I'm going you will beat me to the build but you'd be welcome to come over and check out my setup when I actually get there.
 
No F'n way! You're moving to Lakewood?!? Green Mountain to be exact! That. is. awesome! Hit me up when your here, I'll bring you a fruit basket er something! My VFD finished up many months ago. Its a Teco L510 and the resistor is built in and very weak. It works for low inertia though. Part of me wants to swap out to something that has an external resistor, I THINK that would be pretty easy.
 
What does it even take to do that??? I know a touchscreen but...
 
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Those Nextion screens are pretty easy to work with. There are even libraries for most platforms to drive them. I think I would rather stick with physical buttons, but it's a nice option.
 
OK, I am back. Finally I have it working by going back to basics and building it step by step on the bench with fresh wiring and new walwarts. I found a previous 5v walwart was actually giving out 17v so no wonder things were going awry.



Mechanically it is trivial. The encoder has an obvious place on the banjo driven from the tumbler gears. The stepper sits behind the right hand side of the bed just like Tony Jeffree placed it some 10 years ago, and drives the lead screw via a toothed belt. At both ends I kept the original parts and made brass bushings to fit timing gears with the tailstock end being counter bored to take the "Simmonds Nut". My lathe never had a hand wheel so I did not need to face that complication.



I did not need to drill any holes into the lathe and I can put it back to its original condition in about 15 minutes.



All of my problems came on the electronic side. The switching on the TI board gave a lot of problems as did flashing the board's memory. The software (TI's Code Composer Studio) is distinctly unfriendly. Everything is fine if everything works, but when things go off-track there is zero support. Essentially you must buy Clough42's daughter board, but he offers it very cheaply so that is not a problem. It is also a very good idea to buy the parts for the Control Panel from him, also very cheaply. My efforts with a control panel saw several displays smoke and sizzle under my lack of skills.



With his daughter board you are faced with making 60 solder joints and roughly another 50 depending on how you handle the wiring. This alone stretched my abilities considerably!



Instructions were sometimes unclear. S9 needs to be towards the CAN label. Directions to leave it at "Default" were not helpful as one of the three boards I purchased had the default position towards ALT. I used the suggested hybrid servo with a 4:1 feed and that should have meant programming in 4 microsteps and 1000 resolution, but I had to increase the microsteps to 16 before the speeds were correct.



So at the end of it all, you get to avoid change wheels and to be able to dial in pretty much any thread pitch or feed rate you desire, metric or imperial, and it looks quite cool! I need to add a few thread pitches eg 22 tpi for 5/16 BSF a Whitworth thread, but that should be no problem.



The project is clearly unfinished and we can all wonder what the next steps, if any, will be. Many thanks to RJS and Guns for trying to boost my morale.

ELS4.jpg


ELS0.jpg


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ELS1.jpg


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Just a minor update on the Clough42 ELS.

I needed to add a 22 tpi option so I added a line in the file "tables.cpp".



{ .display = {BLANK, BLANK, ONE, EIGHT}, .leds = LED_THREAD | LED_TPI, TPI_FRACTION(180) },

{ .display = {BLANK, BLANK, ONE, NINE}, .leds = LED_THREAD | LED_TPI, TPI_FRACTION(190) },

{ .display = {BLANK, BLANK, TWO, ZERO}, .leds = LED_THREAD | LED_TPI, TPI_FRACTION(200) },

{ .display = {BLANK, BLANK, TWO, TWO}, .leds = LED_THREAD | LED_TPI, TPI_FRACTION(220) },

{ .display = {BLANK, BLANK, TWO, FOUR}, .leds = LED_THREAD | LED_TPI, TPI_FRACTION(240) },

{ .display = {BLANK, BLANK, TWO, SIX}, .leds = LED_THREAD | LED_TPI, TPI_FRACTION(260) },





Save, flash and reboot.

22 tpi comes up on the Control Panel and actually gives a 22 tpi cut.

This has been the easiest part of dealing with this software.

Of course you can try any thread pitch you desire. I am now going to try loading BA threads which for some totally obscure Brit reason are all decimal inch threads!
 
@ian999 I'm curious, the "daughter board" of Clough's you speak of, this is the boost board? It seems to me there wasn't much soldering to do on this, in fact someone here just bent the 5 connectors that went to the display so they didn't have to de-solder and re-solder those. Being its only real job is to send a 3.0 v from the 5.5v supplied, there must be other ones available?
 
Yeah "daughter board" and "boost board" are referring to the same card that Clough42 fabricates and sells. It does a number of housekeeping chores like having a voltage regulator, EE memory chip (currently unused), and voltage level converters. My failing memory seems to recall something else, but it replaces around three separate circuits and really cleans up things.
 
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