Fixing the Z-Axis Shear Pin
Just thought I would share a little thing that happened recently, and since it does not seem to exist on the internet at all.
Prequel:
A guy was setting up a Wasino LJ-6 CNC lathe that I own, and ended up crashing the tool into the collet. It did not completely trash everything, but it was bad enough that the turning tool had to be replaced (about $150). The collet seemed fine, as did the rest of the machine except that now its throwing an emergency stop error, as if the E-stop button was pressed... except it was not.
The fix:
It turns out on (most? all?) Wasino lathes that they have a safety mechanism of some sort to try to keep the machine from completely trashing its self. There are three different kinds of these safety mechanisms, which kind depends on the model and how new/old it is. There is a clutch like thing on the newer ones, which would be easier to reset, a disk of some sort that breaks when there is too much torque, and the final one is a simple little shear pin.
My Wasino LJ-6mc lathe, and probably all of the LJ series lathes, have a little shear pin in the gearing next to the Z and X axis servos, with a switch that lets it know when it breaks. In the event that it does break it acts like the E-stop is on, and on the Fanuc OT controller won’t go past the bootup screen. When the shear pin switch is activated, diagnostic number 505 gets changed from 00000000 to 00000010 and the controller will /not/ clear the error until diagnostic 505 is reset to all zero’s.
The Procedure
The shear pin is pretty simple. I found out mine was made out of aluminum. I do not know if thats how it came from the factory, but thats what it was and what I replaced mine with. The pin was 0.165″ in diameter if I recall correctly, and it holds a gear and a plate together attached to the ballscrew. Just take off all the covers and take off the Z-axis servo to get to the gearing to replace it.
The annoying part for me was trying to figure out how to clear the controller so the machine could be used again, so here it goes. After turning the machine on, the bottom left corner will flash “not ready”, and appear to not fully boot. After a minute press the parameter/diagnostics button once and page down once to get to the parameter write enable “W/E”, and change it to a 1. I recall it will throw some kind of error: this is normal. Go ahead and press <reset> and <parameter/diagnostic> to get to the diagnostic section of the controller... it should just be a list of numbers with the top left corner of the screen saying “diagnostic”. Page down till you get to diagnostic 505 and cursor down/up until the cursor is blinking under the correct one. type <0> and then <input> on the soft keys. This will clear the ‘soft error’ from the controller. Go back to the parameter list by pressing the <parameter/diagnostic> button a few more times and change back the write enable to a 0. Press <reset> a few times, or at least once, then turn the controller off and back on. I should not be necessary to turn the machine completely off, just at the front of the controller.
You may now continue to profit with your Wasino LJ series lathe with the fanuc OT controller.