Acorn Carousel Tool Changer

[kyanite]

I used the reduction ratio to increase torque of the stepper. This reduced the jerk in start stop motion.
As you can imagine the moment of inertia of a full carousel is significant. I have since upgraded to a larger frame stepper.
I would imagine that with a DMM servo you will need to step down significantly as the speeds achieved by a servo are
far higher than a stepper. I think in this instance with the relatively slow speeds required by a carousel you may be better served
with a closed loop stepper motor as it has high torque at slower speeds.

Yeah I definitely don't want to be using a servo for the carousel. I think a closed loop nema23 with 3:1 will be plenty. I'm surprised you cannot set the rapid for axis independently.
Since it thanks the carousel is a linear axis, could you trick cnc12 into thinking it's moving a greater distance per rotation of the stepper and also increasing the distance of where it thinks the tools are?
I can't see why that wouldn't work for allowing the other axis to move at a higher rapid.

Also thank you for posting this! This thread alone has convinced me to pull the trigger on centroid.

Regards, jamie

[mick41zxr]

No problem.
I started with a 23 frame motor but with the carousel loaded with tools it was on the edge of loosing steps.
I upgrade to a 34 frame closed loop stepper with a 3:1 reduction & haven't had a problem since.
If you want some more info on my setup you can see it here;
viewtopic.php?f=60&t=3900&start=20
I moved the carousel control to an external controller to remove its limits from axis setup. It will with some finesse allow
a roll over function.
Regards,
Michael

[martyscncgarage]

I used the reduction ratio to increase torque of the stepper. This reduced the jerk in start stop motion.
As you can imagine the moment of inertia of a full carousel is significant. I have since upgraded to a larger frame stepper.
I would imagine that with a DMM servo you will need to step down significantly as the speeds achieved by a servo are
far higher than a stepper. I think in this instance with the relatively slow speeds required by a carousel you may be better served
with a closed loop stepper motor as it has high torque at slower speeds.

Yeah I definitely don't want to be using a servo for the carousel. I think a closed loop nema23 with 3:1 will be plenty. I'm surprised you cannot set the rapid for axis independently.
Since it thanks the carousel is a linear axis, could you trick cnc12 into thinking it's moving a greater distance per rotation of the stepper and also increasing the distance of where it thinks the tools are?
I can't see why that wouldn't work for allowing the other axis to move at a higher rapid.

Also thank you for posting this! This thread alone has convinced me to pull the trigger on centroid.

Regards, jamie

You can set slow/fast jog and Max per axis.
Might consider a NEMA gear reducer to add to the motor.

[martyscncgarage]

I'd build trt and build the changer using a reversible gear reduced AC or DC motor, one sensor for tool one, one sensor to count tools and use Centoid's PLC for an umbrella changer

[ridekp]

Hey Marty,

Looking through the posts on umbrella ATCs I have noticed you have mentioned the Centroid umbrella plc a few times. The Acorn ATC zip I have found only contains a rack mount plc and the rest are for lathe turrets. Could you point me in the direction of the umbrella plc?

[martyscncgarage]

Hey Marty,

Looking through the posts on umbrella ATCs I have noticed you have mentioned the Centroid umbrella plc a few times. The Acorn ATC zip I have found only contains a rack mount plc and the rest are for lathe turrets. Could you point me in the direction of the umbrella plc?

There isn't one "YET" for Acorn.
The point being is that they do exist for All in One DC and OAK and can be adapted for Acorn.
If you follow the operational convention of a "typical" Carousel changer it can be done. The issue as you might guess is the input and output requirements for all functions. Ether1616 would be required. It is not "easy" to create a Wizard to allow you to assign those inputs and outputs. What is easier for Centroid, is to take what they already have, create a schematic and PRE-ASSIGN the inputs and outputs. You would have to follow the schematic for for the accompanying Carousel ATC.

I am attaching the PLC Source file for my Atrump Maximill which is pre All in One DC for reference. As well as a "Typical" ATC Schematic for All in One DC to give you something to look at and think about. There is A LOT going on with an ATC, and well defined sequence of events and checking is necessary.

Marty