VMC760 Toolholder falling out!

[snowygrouch]

Hi,
Using VMC760 with 370 controller. Yesterday during a dripfeeding program the toolchange section comes around and at some point during the carosel operation the whole toolholder fell out the chuck, landed on the job and shattered the carbide cutter...which I was none too pleased about.

Anyway I cleaned the tapers up and started again, thinking it must have been a freak occurence....5mins later it does it again. So I jammed the stop button and have no intention of using the mill again until I have some idea what might be going on.

I`ve been using the mill for about 5 weeks with the same toolholders etc and no problems, only things I`ve noticed are that the head sometimes has to pull very hard on the holder to release it when it leaves a tool in the carosel. Also every now and again when taking tools in-and out setting lengths etc it gets confused about which tool it has in. So might say T4 when it actually has T3 in.

This is the 1st CNC I`ve ever used, when you switch on the air supply there is a permanent hissing coming through the spindle even when idle...which now seems very suspect.

My initial thoughts are air pressure problem or faulty air valves/lines/fittings?

Any ideas (other than calling the repair man), much appreciated.

Thanks

Calum

[sjonnie73]

Hello snowygrouch,

I think that you have to call for service.
I believe that your spring washers in the spindle are broken.
These holds your tool in the conus.
It is normal that when you change your tool that you hear air coming through the spindle this is to keep swarf out when you change your tool.

Kind regards,

Joop Coret

[gus]

I have had my VMC1000/22 drop tools because the tool change height was a bit off.

Does it seem to be holding the tool correctly?

Is it only one tool or many tools?

spring washers, grippers, retention knobs...

[snowygrouch]

Hi Gus,
It seems to hold the tool fine once its in. It happened to at least 2 different toolholders. The shop manager has booked a repair man...so thats a week lost.

Only ever happens during toolchange

Thanks for your reply

Regards

Calum

[underthetire]

My guess is the ATC is not lines up correctly, or tools are sweating in to the spindle taper, or not un-clamping correctly. I have seen this when spindles are going bad, taper heats up and sticks tools in the spindles. The atc will jar it loose, but not grab it correctly.