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Miyano ATC stuck?


Jul 29, 2022
Hi everyone,

This past weekend I got my Miyano TSV-35 hooked up to power at my place and I proceeded to get it reassembled. When I purchased the machine at an estate sale, the ATC did not work and was throwing a Z axis over travel error. I was able to get this issue resolved yesterday (https://www.practicalmachinist.com/forum/threads/atc-over-travel-error-on-fanuc-21m.404756/) and the ATC rotated but seemed to only rotate halfway to the next tool when it stopped and threw an error. I believe the error was Alarm 25 = the sensor behind the ATC to make sure it's aligned with the tool holder fingers:


With the ATC in a position that would cause damage if the Z axis were to come down, I started to look into how I could get it rotated into the correct position. When I applied a slight amount of pressure to the tool changer, I felt and could hear that it was slightly rotating but it was getting stopped by the ATC motor on top. I removed this motor and was able to rotate the tool changer quite easily until the next tool aligned with the spindle and then it stopped. I put the ATC motor back into place and bolted it into the frame. I then proceeded to get the z axis down and look into the 22 alarm that I was getting. It was because the following cam is not aligned with the outside sensor:


I know that when I got the machine hooked up, this cam was aligned correctly and both sensors had a red light on them. Currently only the inside sensor has the red light on. If I put a metal ruler against the outside sensor to make it think that the cam is correctly aligned, then I get an 20 Alarm which is related to the following sensors showing a different tool index than what the machine thinks (my guess as they set the 4 bits for the current tool index):


At this point, I got the z axis back above the ATC as if it was going to rotate the ATC. I removed the ATC motor again and was hoping to rotate it by hand to get the cam aligned but it's locked. It won't rotate left / right and there is a clear mechanical lock. I started looking into the wiring harness that goes to the ATC and saw that it only has 7 small wires: 4 sensors on the front for the 4 bits, 2 sensors for the cam and 1 sensor for the tool holder finger location:


Further examination shows that there is nothing else going to the ATC, the air line goes into the Z axis body as can be seen above. I also looked in the opening for the ATC motor but there was nothing except a single gear:


At this point I'm not sure how I should proceed. In my mind this is a purely mechanical solution that should allow for the ATC to rotate by hand if the ATC motor is removed. There is a plate closing the backside of the ATC casting but I would need to remove a couple of the finger assemblies to get the plate removed:


Do I remove this plate along with a couple of the finger assemblies to see what the ATC looks like inside and to see what might be getting caught up? Or am I overlooking something?

Any ideas or suggestions will be greatly appreciated.

I figured out the problem and was able to get everything lined up again and fix all the alarms. When I removed the top plate, I was able to grab the gear with my entire hand and rotate the ATC.

What I did find was that there is a lot of backlash once the tool is lined up with the spindle (in this backlash area the ATC can be rotated slightly by hand). To make it move to the next tool, the upper gear rotates quite a few times, the cam on the side of the ATC rotates 30-45 degrees before the ATC actually rotates. When it gets to the next tool, the same backlash is present.

I was able to run the tool change quite a few times and each time the ATC motor does not seem to compensate for this backlash. Each time it stops in exactly the same spot going from T1 -> T2.

Would there be a duration parameter for the ATC motor to run for before the brake is activated on the ATC motor? Or would this be in 9003 program?
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