[cobrakai]

The other day while using my machine, the head came down slightly off-center on a tool in my ATC and pushed the ATC out of alignment. As you know, the force of the head and ATC air cylinder are pretty strong so this misaligned the ATC before I could press the Emergency Stop. I checked my compressor and it was reading 100PSI. I've followed everything by the book as far as PDB and ATC setup.

I spent over an hour resetting it according to the Tormach procedure and noticed that many of the tools will move slightly (1/8") when the spindle comes down on top of them. There is a few degrees of backlash in the system, combined with the plastic screw mounting, it seems easy to have this kind of problem again. I definitely DO NOT want to have it happen again though!

Questions...
When you are using your ATC, does your spindle move your tool slightly or are they all perfectly aligned? How much backlash is in your ATC tray?

When your ATC air cylinder moves in and out, does it make a clunk as it reaches each end of the travel or is it quiet and smooth? Mine seems to hit each end somewhat harsh and shakes the tools. I am guessing this slowly worked the ATC out of alignment over time.


Any tips or tricks you can offer for safely using the ATC would be helpful! I am afraid to leave it unattended now. Once is enough for something like that. Luckily, it is back up and running smoothly now and I don't think anything was damaged.

[SCzEngrgGroup]

Having designed several ATCs using TTS tools, I can tell you that a fair amount of "slop" is pretty much required for a TTS ATC to work properly. The trick is to adjust things so the "slop" is symmetrical about the spindle, rather than being offset in one direction. The slop must be small enough that the spindle can't come down and miss the taper on the TTS shank, because if it does, bad things WILL happen. In theory, on the Tormach ATC, the Nylon screws holding the forks to the carousel should break first, preventing the alignment of the entire ATC from being knocked out.

I've seen a couple of posts from people with the Tormach ATC that had the coupling between the carousel and stepper motor come loose, which introduces a great deal of backlash on the carousel position. That would be something to check if you really have a lot of backlash.

Regards,
Ray L.

[spletcher1]

I had this exact same thing happen to me. I had to disassemble the turret a bit and then reassemble it while making sure everything was tight. At the time I found that the carousel had some play but, in addition, if I gently pushed it after it apparently came to a stop, it would slide by about anouther 5cm or so. I believe that this is what caused the head to miss the tool and bend the ATC out of alignment (the plastic screws did not break for me. This "slip" was corrected by tightening the main nut.. After I got everything realigned, I spent alot of time trying to get it perfect and symmetrical in backlash. Nevertheless, it still moves slightly when the spindle comes down on top of the tool. I don't think that there is anyway to completely avoid this.

I understand your uncertainty regarding the rate and characteristics of tray movement in and out during a change. I found little information about how exactly one should adjust this, and unfortunately the Tormach guys (who are generally very helpful) didn't provide much guidance. Even after lots of time playing the the damper screws, it still clunks a little.

Perhaps the thing I find most difficult is regaining the trust in the unit enough to let it run without constantly monitoring it. I hope that will come back!

Scott

[cobrakai]

Exactly. I tried disassembling it as well and found that the two set screws on the shaft will greatly affect the amount of backlash.

Same as you - when my spindle pushed the tool down, the plastic screws didn't even budge. The whole ATC was pushed downwards and slipped on the mounting point. So the 2nd time I tightened them more too. The only good thing about this was that my tool didn't get damaged.

It's working great now. Very little backlash or wiggle on the tools, but I can't leave it alone.

[CadRhino]

Just curious, did you go through and redo the ATC alignment like Tormach shows in this video? How to Align the Tormach ATC (Part 2 of 2) - YouTube

My ATC does make a clunk sound and it has not been crashed (yet).
Sometimes the ATC seems very delicate, sometime it seems just fine. I think Ray's response is good - you want the slop in the right location/center. Good luck.

[cobrakai]

Yep I followed his video and read the setup guide as well.

I think the air cylinder smoothness wiggled things loose just enough to get out of alignment. I made sure to tighten it all more and I will mess with the air dampers.

[BAMCNC.COM]

https://www.youtube.com/watch?v=VjlweEjBVk0

If it's apart, follow this video. Never had a crash since. I did that video 6 months ago.