Plastic Tool Holder Fingers Keep Breaking (Torq-cut 22)

[MetalicGlow]

I have a 1998 Torq-cut 22. For years I used this machine and never needed to replace a carousel tool holder finger segment until I lost CMOS settings a few months ago when the correct tool change height parameter was lost.

I fixed that problem and re-calibrated the tool change Z height so every thing was working properly until about the last month or so when it began breaking tool fingers at a rate of 1 per week. I continually check tool change height and it looks fine to me.

Is this recent string of breakage due to embrittlment of the plastic from old age or heat cold cycles in the shop? (The temp range in my shop year round is from 41F - 130F)

Or, am I not setting tool change height correctly?

I have the Z height set so that the carousel tool fingers will actuate to the right and engage the CAT-40 tool holder slot in such a way that the tool fingers will be very slightly distorted upwards. Then, when the tool is released from the spindle, the tool fingers will be very slightly distorted downwards until the spindle pulls away. Once the spindle pulls away, the fingers are parallel and sitting normally. Is this correct? It seems like that is a happy medium between distorting the fingers up and down equally during the tool change cycle.

[machintek]

The tool change height may be correct but there may be other factors.
What if the knock out at the end of the draw bar stroke has changed and is not there. Thus the tool can stick inside the spindle but the plastic fingers are too weak to break the tool holder free.
What if the switches on top of the draw bar cylinder are out of adjustment? The spindle may go up before the tool is completely released. Again the fingers could break.
Just giving you things to check.

George

[MetalicGlow]

Thanks for the reply George.

I have no idea how to go about checking for those posible problems. Would you know of a BP tech in the DFW area?

[tpmx57]

I had a problem one time with my tool changer and finally tracked it down to my air pressure being low.
It was high enough to keep from getting the "low air pressure" message but not knock out the tool during tool change.
If I remember right it just faulted out but that was awhile back.
Just an idea.
Good luck getting it fixed.

[MetalicGlow]

Originally Posted by tpmx57 I had a problem one time with my tool changer and finally tracked it down to my air pressure being low. It was high enough to keep from getting the "low air pressure" message but not knock out the tool during tool change. If I remember right it just faulted out but that was awhile back. Just an idea. Good luck getting it fixed.

That is interesting. Did the low pressure condition cause tool finger breakage?

Sometimes other processes in the shop put a heavy load on the air compressor and I get the low pressure fault but it is a rare occurrence.

Also, I am beginning to heavily doubt the problem is with releasing the tool holder from the spindle because only one out of two fingers are breaking. I would imagine that a direct upward force on on BOTH fingers simultaneously would break BOTH fingers. I noticed two more cracked - but not yet broken off - fingers after inspecting the rest of the segments. In each case - whether cracked or broken off completely - the fingers are fractured from what appears to be a HORIZONTAL force, the same force used to spread the fingers apart.

On another note, my machine from day one will sometimes make a loud "BANG!" while popping the tool holder free from the spindle. I don't know if this signifies a problem or not. It happens maybe one in 50 tool changes. Does this happen with your machine?

[tpmx57]

No mine has never broke a insert.(knock on wood)
When I had the low air pressure problem I beleive the tool wouldn,t get ejected and would give an error.
I don,t remember exactly what the error was it was awhile back.
Mine runs through the tool change real nice.
I love the machine and have only had a couple small problems with it.
There is some excellent help on here from George and the others.
I will be watching to see what you find out.
The air pressure was just something I ran into and may no way be the culprit on your mill.

[tpmx57]

Something I just thought of also,does your spindle orient correctly before
the move into the changer?
If orientation is off I think the holder would hit the fingers on the backside were the notch is.
Just an idea.

[MetalicGlow]

Originally Posted by tpmx57 Something I just thought of also,does your spindle orient correctly before the move into the changer? If orientation is off I think the holder would hit the fingers on the backside were the notch is. Just an idea.

Everything seems to work fine. The spindle completes the orient before the carousel actuates. I replaced the spindle encoder in 2002 and hasn't been a problem since. It has been a few days since the last time a tool has dropped from the carousel as a result of a broken finger. I am just waiting for the next one to drop. It should be anytime now,. Hopefully I will be watching when it happens.

[tpmx57]

Just checking back to see what you found out.
Hopefully the problem went away on its own.

[MetalicGlow]

Originally Posted by tpmx57 Just checking back to see what you found out. Hopefully the problem went away on its own.

I have not broken any more of them since my last post. I will be ordering 5 replacements and installing them. If any of the new fingers break then I will know for sure that they are not breaking due to age.

I've made is a habit to closely pay attention to tool changes, looking for anything amiss and it all looks normal to me.

I will post if any more break.

Take care.

[MetalicGlow]

My machine just broke yet ANOTHER plastic tool holder finger. I was lucky enough to actually witness it this time. The tool carousel actuated to the right to engage the CAT 40 tool holder already in the spindle and INSTANTLY broke off one of two fingers (as usual). This happened BEFORE the spindle moved. And.. it happened before the drawbar clicked to disengage the CAT 40 tool holder.

So here is what I think may be happening:

The tool carousel actuates TOO FAR to the right. What else could it be? The plastic tool holder fingers seem to be exactly aligned in relation to the tool holder grove.

What controls the stopping position of the carousel as it approaches the spindle?

Another observation:

Right now I have 7 broken tool holder fingers. Every one of them have just one finger broken. Could it be a coincidence that it is the finger closest to the electric cabinet in each case? Why would it favor breaking the finger on the same side each time?