Toolholders sticking in spindle

[KevinV_MEI]

While this is happening on my VMC1000-30, it surely must happen on other machines too. We are running a job that has to run for 35-40 minute with a tool that uses a lot of power and creates a lot of heat. When the tool path is complete the tool sometimes sticks in the spindle and faults the machine on the tool change. Any tricks to keep it from sticking?

[Geof]

The only trick I have ever figured out is to change the tool out and back into the spindle part way through the machining. Do it more than once if necessary.

[KevinV_MEI]

That's what I was thinking. And add a M25(the command for taking the spindle home and readying it for manual tool change), M00, have the operator break it loose with a few hits of the drawbar button, reinsert it and continue the program.)

[gus]

my guess is that the drawbar needs adjusting or the air supply is not right. My DMg needs to have the tool popped in the morning, but not in the middle of the program, and neither of my VMC1000/22's ever had a problem

[machintek]

Very common especially with a new spindle and new tool holders and a prolonged heavy cut. Even when the knock out is correct and air pressure is correct.
Most reliable solution has already been mentioned, Do a M01 or M00 and break it free (after the run of that tool) and put it back in.

George

[KevinV_MEI]

Thanks George. That's what we're up against. Lots of heat, side pressure, up pressure and long cutting times are seating a 2" shell mill holder pretty tight. The holders are nearly new and the spindle has recently been rebuilt/reground. Was having drawbar/pressure issues in the past but now have those resolved.

Kevin.

[Geof]

One thing you can take comfort in is that the spindle regrind was very precise; one solution for holders sticking is to have a poorly fitting taper. I am not sure that is a good solution.