Fagor 8055Tc control. 2 axis lathe. Servos connected to each axis screw by belt.
Yesterday, while setting tools, noticed that the X axis seemed to jump when the direction of motion changed(using the hand wheel). Attached indicator to measure the motion. Set hand wheel movement to .01" per click. One click of hand wheel measured .01". One click the opposite direction measured .015". Continue in same direction, each click commanded, .01" movement. Screen display showed proper change of diameter=.02" per click in either direction.
Got the same amount of jump(.005") with .001" and .0001" hand wheel settings.
Okay, does Z axis do the same thing? Not exactly. Same sequence as X. Measured movement is .01", then .008" in opposite direction. Continue in same direction, second click .009", subsequent clicks, .01". Set to .001" per click. Takes 2 clicks to get .001" movement when changing direction.
Something to do with backlash parameters? Changed them to zero. Same results.
This morning, cold machine ( 55*F), same set up and sequences. 01" commanded per click. X axis only moves .009", Z axis only moves .005". Subsequent clicks in same direction .01" for each axis. Set to .001" per click. X axis takes 2 clicks to get .001". Z axis takes 5 clicks.
Thrust bearings? Loose nut/mounting? Bad ball screw? Stretching belts? Loose/ bad sheaves? Parameters?
Don't seem to have enough functioning little grey cells to figure this out.
Yesterday, while setting tools, noticed that the X axis seemed to jump when the direction of motion changed(using the hand wheel). Attached indicator to measure the motion. Set hand wheel movement to .01" per click. One click of hand wheel measured .01". One click the opposite direction measured .015". Continue in same direction, each click commanded, .01" movement. Screen display showed proper change of diameter=.02" per click in either direction.
Got the same amount of jump(.005") with .001" and .0001" hand wheel settings.
Okay, does Z axis do the same thing? Not exactly. Same sequence as X. Measured movement is .01", then .008" in opposite direction. Continue in same direction, second click .009", subsequent clicks, .01". Set to .001" per click. Takes 2 clicks to get .001" movement when changing direction.
Something to do with backlash parameters? Changed them to zero. Same results.
This morning, cold machine ( 55*F), same set up and sequences. 01" commanded per click. X axis only moves .009", Z axis only moves .005". Subsequent clicks in same direction .01" for each axis. Set to .001" per click. X axis takes 2 clicks to get .001". Z axis takes 5 clicks.
Thrust bearings? Loose nut/mounting? Bad ball screw? Stretching belts? Loose/ bad sheaves? Parameters?
Don't seem to have enough functioning little grey cells to figure this out.