Denford Software & Machines

I'm having trouble with the ATC on the starturn 5 locking up.
I can use any of the tools fine selecting and rotating them until I use the parting off tool. If the tool starts to bind/chatter this cause the problem. When I try to select a new tool after this has happened I can here the motor change in sound (swapping from reverse to forward) but it won't move.
The only way I can free it up is by removing the small metal cover plate on the opposite side to the motor, disconnect the power to the motor, get a 10mm spanner and carefully turn the nut/motor shaft until I can feel it free up. Once I have done this all is well until it binds up on parting again.

Looking at the Tp121.PDF (diagram for the Novaturn ATC) my ATC is a little different in that it only has one tool height adjustment pawl. I wondered if the second was added to improve the design, is mine locking up because of the loading on the taper bearings. I can't feel any play or end float in the ATC. I have in the past stripped the tool holder off, taken the motor off to replace its gearbox and also the position encoder end. I have not touched the main shaft or the cross shaft.

Is there any further info on how to set these up (torque settings, etc)

Thoughts and Ideas Please

Thanks
Pete

It sounds like the parting off is the issue if it cuts ok.

Everything has to be perfect.

As close to the chuck as possible.
Correct centre height.
Coolant if possible.
Sharp tool.
Correct speeds & feeds.

What material are you using?

Machine is a Starturn 5 so no cooling option,

Centre height is spot on, I spent quite sometime ensuring this is correct, I've been working through all the tools to ensure no nipple on a face off, starting low and adjusting the pawl a fraction after each pass.

Material is steel of unknown grade.

What I suppose I'm trying to work out is what is happening in the ATC that is locking it up. Even if I swap between trying to change tool so motor runs forward and staying with the current tool motor runs backward it wont move. I have to do the same action and it doesn't require much force on the other end of the shaft to the motor with a spanner (motor power disconnected).

I have always had issues with parting on either the Harrison M300 at work or My Boxford TUD in the garage, always try for min overhang in tool and material. More investigation is required into the speeds and feeds as obviously as the Dia of the bar changes these need to change too. Looking at code produced by Lathecam or Quickturn 2D It looks like the speed/feed stay constant rather than changing with the dia on the material.

I'm also trying to workout what I need to set up for speeds and feeds for all forms of turning on the Starturn 5 as it has a max spindle of 1800rpm. All the machines in QT2D are running well over that at 2800

I'm going to do a different post about this because I have lots of questions about terms using in tool and material definitions.

Cheers

Pete

it's probably the reduction gearbox that sits under the motor. One of the gears gets damaged over time and stalls the motor.