Mini wannabe datron build

Very cool.
Re way covers, I was looking at some similar machines and the linear rails extended past the frame unsupported to support the covers and/or bellows. (I have been looking at cast iron frames similar to this for a project..)
 

ihavenofish wrote:

Hmmm. I might be able to SLS print the way covers from nylon.
 

FYI... nylon swells like mad in coolant.  It doesn't really break down like paints and rubbers, but it does swell; sliding fits or interlocking channels may get tight or bind up.  I've had to drill out plenty of nylon set screws in fixtures which were intended to keep chips out of unused holes.

If you aren't planning on waterbased coolant they should be fine, but if you *might* run coolant in the future I'd stay away from nylon.

I used a combo of 3/16" PE sheets and PETG prints for my carousel ATC cover and door.  Less heat resistance of course, but both are dimensionally stable in flood coolant.

Side note - rodw's mention of rail extensions used as way cover mounts is right on the money.  This is exactly how my mill's front Y-axis and Z-axis cover ends are mounted.

I run mist/mql. wont get flood.

I expect the nylon to swell, I don't *think* it will be an issue in these uses, but we will see soon enough. I don't have any sls parts handy to test on right now. Nylon SLS is the cheapest print form services except SLA resin which is usually not acceptable for these uses. I could definitely print the atc hat on my printer here from abs or petg though.

"Side note - rodw's mention of rail extensions used as way cover mounts is right on the money. This is exactly how my mill's front Y-axis and Z-axis cover ends are mounted."

physically mounting the way covers is a non issue for me. my main problem is simply making them fit. this machine is really small and extending 100mm for way covers each side actually adds like 30% to the machine length. Don't want that.

on the topic of my atc. seems a good reason to try and text the lichuan ethercat servos. 40mm 50 or 100w model.

Does ethercat works WITH the mesa card already there? as in, can i use both? or do i need to switch to all ethercat?

ihavenofish wrote:

on the topic of my atc. seems a good reason to try and text the lichuan ethercat servos. 40mm 50 or 100w model.

Does ethercat works WITH the mesa card already there? as in, can i use both? or do i need to switch to all ethercat?

Regarding Eth & Mesa, I think they can both work... but you should wait for someone with more experience to confirm.

As for the ATC, I've only read about (far as I remember) one person who reported using an AC servo to control a carousel... and they mentioned quite a bit of fiddling to get the servo tuning right.  Unless you've got a really high ratio gearbox a servo is likely to see a pretty serious inertia mismatch.  Maybe an AC-powered ethercat stepper would be better in this application?  High torque at low speed, no tuning, and stall/alarm feedback via Eth in case of a problem...

And there's no need to 'use up' an axis letter for control of the carousel; you aren't doing coordinated multi-axis moves with the platter.  Carousel.comp works quite well at managing the platter movements & rotation and doesn't require much in the way of sensors.  The tool change sequence is still handled via g-code subroutines and and M6 remap.

In your case (i.e. half-platter), you set up carousel for the full compliment of positions to get the spacing correct, and just write your subroutines to never command those pocket numbers.

..."to never command those pocket numbers that don't exist"

[I'm not going to tempt the Forum Editor of Doom]

Whilst mesa and ethercat might coexist as they NIC they use are defined for each environment, the question is why do that?
Ethercat can do everything a mesa card can do and then some.
Re the tool changer, I have not had any experience with them either but I think using a low cost stepper would make sense.
An ethercat stepper driver from Leadshine or Rtelligent  would solve the problem. Not sure about Leadshine but Rtelligent make both open and closed loop ethercat drivers. For Nema23/24, ECR60 = open loop, ECT60 = closed loop.

thanks

I'm stuck now anyway. I ordered some "precision collet reducers" and one wound up with 0.0028" runout, and the other was 6.32mm instead of 6mm.

That's worse than even the most garbage $1 aliexpress collet reducer.

Sigh. now I need to figure out something else and likely wait weeks for it to arrive...

rodw wrote:

Whilst mesa and ethercat might coexist as they NIC they use are defined for each environment, the question is why do that?
Ethercat can do everything a mesa card can do and then some.

Um, cause the machine is already running on the mesa and i just want to add one motor?

Not sure why you guys think a stepper would somehow be better than a servo? a nema 17 stepper has less torque than a 100w servo. I dont think inertia would be an issue on such a tiny magazine (only 120mm diam). it will only be moving about 100rpm with quite low acceleration.