Build thread:Magnaturn 612 retrofit(s) - Southbend

[frijoli]

Just beginning to work on these.
Both machines appear to have been used in a light production/training commercial environment as opposed to a trade school.
Plan is to install DMM AC servos on one of them, and the other I haven't decided. (I already have a pair AC servos and drives)

[frijoli]

DMM vs factory

[frijoli]

Okay, I have a question about the Turret set-up
This machine has a Stepper drive motor and an encoder on the turret shaft itself. Since Acorn doesn't have encoder inputs I have to change the process.
This is an 8 position turret, AC solenoid to unlock, and a key/wedge to lock once in position.
What are my options?
I am thinking a 3 bit absolute encoder like is on the Denford machine Marty retrofitted will get me the position, but my lock/unlock is different, and I don't know where to get an encoder like that.
The marked up pictures: (some of these pictures came from dbensavage retrofit)
RED is the drive motor location
BLUE is the Encoder/Turret shaft
GREEN is the solenoid control
In the second picture, the bar at the bottom of the image, above the turret housing is the arm with the locking wedge. The solenoid lifts this out of the notch in the turret shaft. Normally it's laying in the housing but it is vertical for taking pictures

[frijoli]

Just ordered my Acorn/Lathe Pro for one of these!
Also I am going to test one of these boards from CNC4PC to convert from open collector(single ended) to differential for my encoder. As I mentioned I have 8 well made Japanese encoders with seals and bearings that I would like to use. if it doesn't work, I am out of pocket about ten dollars.I will use this for my Turret home sensor as well. Assuming it works correctly.

Also going to use this adapter board, and these connectors for the DYN 4 drives.

[BASE]

I have no useful advice but I’m looking forward to seeing you get them running.

I’ve never seen one of those, they look like neat little lathes.

[martyscncgarage]

Frijoli,
When did you get that C84ACORN Board? I discovered an issue with it and CNC4PC redesigned it. It uses the fault output to enable and disable it.
I hope they are still not selling the older version.

You can use an open loop stepper to control the turret without the encoder. Unfortunately, the control will not know what tool it is on. BUT should work ok. You need a gray logic encoder if you want CNC12 to know the position of the turret for sure.

How does the turret lock/unlock. Can you post the exact tool changer operation? Is it unidirectional or bidirectional?

[frijoli]

Frijoli,
When did you get that C84ACORN Board? I discovered an issue with it and CNC4PC redesigned it. It uses the fault output to enable and disable it.
I hope they are still not selling the older version.

I do not have the board yet. I ordered it last Friday. I would hope this is current.

You can use an open loop stepper to control the turret without the encoder. Unfortunately, the control will not know what tool it is on. BUT should work ok. You need a gray logic encoder if you want CNC12 to know the position of the turret for sure.

I plan on ordering an open loop stepper and driver today. I don't know where to find 3 bit/gray logic encoders, so I will just use a home switch and step position.I'm planning on using single steps, and this unit has a gear reduction, so I am not likely to lose position.

How does the turret lock/unlock. Can you post the exact tool changer operation? Is it unidirectional or bidirectional?

I have no information on the actual intended function from Southbend. There is a lever with a locking bar that drops into the notch on the turret shaft. The solenoid lifts the bar to unlock. You should be able to discern this from the pictures above. The upper image shows the bar lifted away to show the notches(blue) and the solenoid location (green)
There is nothing to make this unidirectional mechanically. So I believe I can do whatever works best.
I hope that answered your questions.

Thanks for you help!

[frijoli]

I had to bore out the mount for the larger shaft and coupling.


Z axis motor spacer.

Assembled Z mount with DMM motor.

[martyscncgarage]

OK.
Ask CNC4PC if they are shipping the C84Acorn rev monitoring the Fault output.

If you can put a switch/sensor on tool one and possibly a switch or sensor on the bar to denote it is in and locked that might be helpful. (Software could be made to look at this input to check its state BEFORE continuing)

You can use a 4 bit gray logic sensor. But I have yet to find one available on the market.

[frijoli]

OK.

If you can put a switch/sensor on tool one and possibly a switch or sensor on the bar to denote it is in and locked that might be helpful. (Software could be made to look at this input to check its state BEFORE continuing)

There will be a turret position switch of some type. There is a shaft extension on the turret that is readily accessible and I can put a flag and sensor on it.
Putting a switch on the bar is a great idea!
Should also be easy to implement.

Thanks