Fawne Fadal, Unchained. (4020 Fadal Retrofit)

[BattyZ]

Fawne's Toolchanger started to fail. The swing arm motor would need assistance or fail to complete the swing. I thought for sure that little gearmotor had given up the beans. I would rather not talk about how long it took me to find a bad 'ice cube' relay. 2 days. Anywho that motor has new bearings and new gearbox grease! Not to mention brand new ice cube relays in both cabinets.

As I was testing the rebuilt swing arm setup, I noticed something. The half moon that runs the Geneva mechanism was never really stopping in the same place. Sometimes it would be halfway out. Fawne would drop tools ever so sparingly. This is probably why. For a good day and a half, I fiddled with the mechanical settings and tried to add delays, in various spots, to the code. The delays were interesting because they had to be a certain length, otherwise, the EMF field would not have enough time to dissipate, causing the motor to go further in the wrong direction. Could not find a Goldilocks combo between software and hardware. Which led to this:

That's a 50:1 precision gearbox with a closed-loop stepper from my cnc router project. Quite pleased to be able to upcycle. The specs match up nicely as well so a nice drop in. Running this under Axis7. It's zero'd on INIT. All moves are relative. Need to credit DojoJoe here for the inspiration, thanks! I know it's not a full servodrive umbrella but we are back up making chips, with ummm, 'stuff I had laying around?'

This is the basic gist of it. This is not the final. I am down with the flu currently and away from the shop, so I wanted to post something otherwise, would not get around to it. Code does all the math, keeping the 'pocket math' from earlier. Then does 1 move instead of consecutives.

Also got my dual monitors set up too! Time to hit up the screen editor.

If anyone is keeping score... put 2 more on the board for Dynomotion!

[DojoJoe]

Looks like you beat me to it on adding a servo to the carousel. I'm about to jump back into working on mine - I got tied up with a couple machine installations for customers (and building a compressor that can handle this addition to my shop since mine was dying - again this is more so of a product in development for me than something to make production so it's a bit low on my priority list).

Honestly I like the look of your setup - I think it turned out a bit cleaner than what I have intended on mine (I've got a delta servo motor and everything on hand to convert it, just no time yet to do so), I'm curious how easy it was to put a timing belt on in that area (I'm assuming you put on sprockets for a timing belt).

[DojoJoe]

I wanted to just edit my post above, but oh well.

Did you just mount the Genevia gear / wheel / whatever it's called straight to the gearbox? I'm seriously curious how well that works since I'm assuming that's what you did - I really want to try this - I need to get a gearbox for my servo now, that makes it so easy if that's what you did.

I'm so curious how quick you could move it like that (for sizing a servo motor there's a formula, for servos you want the inertia ratio to be less than 15 typically - though some motors can have a higher inertia ratio than others, for steppers I believe the number is 5, I could be wrong on this since I don't use steppers. This is from memory, but inertia ratio = inertia of the load / (inertia of the motor * gear ratio^2), where inertia of the load and inertia of the motor are the mass moment of inertia typically given in kg m^2, also referred to as rotor inertia in some servo documentation - when the inertia ratio is too high you'll get an unstable system such as the servo hunting for position and if the number is ridiculously low it means the motor is oversized or you've got more gearing than you need).

[BattyZ]

Yes, I just mounted the 'half moon' onto the output shaft of that gearbox. Well, had to make an adapter. The belt drive setup you spoke of would be sweet but needed the machine back up.

I don't think the umbrella is spinning much faster than OEM. With the start/stop motion of the geneva it starts to jostle all the toolholders. With a directish-drive and a plastic ring, maybe 2, to keep the toolholders in place; one might be able to rotate with some speed. How fast would be worth it though? I pick up way more speed not being hindered by a baud rate and being able to run the latest toolpaths. Still, a zippy tool changer would be neat!