Y axis slip

[Mugsowner]

I am firing up a C maachine I picked up a while back, but was waiting for updates to my DC system to run. As it finds the bit, truck moves across Y to plate which snaps out to be found. The motor continues to turn 3 more teeth on the belt stops Z goes down finds plate comes back to ke board side and tells me Y axis slippage. I think the belt is tight enough.

[bergerud]

Mark the belt and the y motor sprocket with a felt pen and try again. I bet you find the y belt slips as the truck thwacks the bit plate.

[Mugsowner]

No felt pen req. I see the truck move across to bit plate. Once there it stops, but motor still turns a bit causing belt to jump. This I can see and hear happen.

[Mugsowner]

How does the Y motor know when the truck hits the bit plate side of machine. The last owner stated that this machine was in for service and never ran since, so I figured letting it sit until I was rigged for it would not be an issue. In my view the belt is not slipping. It is a cog belt and as the motor tries to pull the truck though the side of the machine, the belt jumps teeth until motor stops turning, normally two or three teeth.

[bergerud]

Under certain situations, the controller monitors the current draw of the servo motors. For example, it monitors the z motor current to detect the bit touches. It also monitors the y motor current when it homes to set up the y coordinate system. It detects the end of y travel when it touches at the keypad side. I am not sure, but I do not think it monitors the current during the slam at the bit plate. I think it knows how far the bit plate is from the touch at the keypad side. I do know that if you try and stop the y motor in the middle of travel, it is powerful enough to just slip the belt.

In your situation, the slam at the bit plate slips the belt and then when it does the home check back at the keypad side it finds out there was a slip. I know of no solution to this but to tighten up the belt. Maybe the sprocket or belt gets "polished" and more easily slips.

Edit: When it homes for the first time at the keypad side, does it make it all the way to the end of travel? I am thinking that if it did not, it would think the bit plate was further away and slip the belt trying to get there.

[aokweld101]

I had a problem with the y-belt slipping took the y- belt loose and visaully checked it sure enough I had a klog missing, to make sure, I would check it... it's always the little things to make you think you have a bigger ploblem

[bergerud]

Good point Aubrey. I always get excited about the theory and overlook the obvious.

[Digitalwoodshop]

In theory when the motor clicks 3 times at the bit plate it is telling you that the servo motor splined shaft is slipping 3 teeth because the gap between the shaft and big plastic gear is too wide. This is normally caused by worn out 685ZZ Bearings in the Y Gearbox.

AL

[bergerud]

Here is another overlooked obvious. Check the set screw in the belt tightener. If it loose, the belt will compress the spring and slip while whacking at the bit plate.

[Mugsowner]

Good call on the screw. Thank you, I did glance at it and it looked tight, but reach in there and grab it tells a different tale. Now the machine will attempt to carve. Now it is has an issue with depth. I am doing a carve with .032 depth, and all I get is a air carve. I dropped depth to .062 and It air carved again. I messed up a number , so I know it will carve deeper (What a differance a zero makes). I am running a test board at this point.