andrewkeisler
Aluminum
- Joined
- Apr 23, 2012
- Location
- Knoxville TN
1992 fadal 4020, I'm trying to find where my lost motion is coming from, other then the thurst bearings. My question is, to check motor couplings can I grab the end of the screw (I'm working with the Y axis) and twist back and forth? Should it move at all? It was a trick to convert the little motion it has into set numbers, but this is how I (think) I did it.
I took a indicator holder (just the holder) and clamped towards the end of the ballscrew. Theres a flatspot on the holder which is the surface I indicated on using a .0005 test indicator, mounted to a magnetic base and placed on the y axis boxway. (Both the holder and indicator are positioned perpendicular to the screw.) When I would twist the screw, the flat spot on the holder would actuate the indicator. I figured my high number from twisting one way and the low number when twisting the other way. I then jogged the Y in tenths until the same differance was achived from the hand twisting technique.
I came up with .0004, which accounts for the extra lost motion.
.0016 at the table and at the ball screw
.0011 on the end of the screw (thrust play)
I hope my "test" is somewhat understandable. Does anyone have another way to check for lost coupler motion?
If I put bearings in and then did the old push and pull technique and came up with no movement in the table but had .0004 backlash when jogging or running a BL program, that would more or less tell me its the coupling or motor, right?
I would like to test the Z somehow but with the weight of the head, I doubt my test would work well.
Thanks, Andrew
I took a indicator holder (just the holder) and clamped towards the end of the ballscrew. Theres a flatspot on the holder which is the surface I indicated on using a .0005 test indicator, mounted to a magnetic base and placed on the y axis boxway. (Both the holder and indicator are positioned perpendicular to the screw.) When I would twist the screw, the flat spot on the holder would actuate the indicator. I figured my high number from twisting one way and the low number when twisting the other way. I then jogged the Y in tenths until the same differance was achived from the hand twisting technique.
I came up with .0004, which accounts for the extra lost motion.
.0016 at the table and at the ball screw
.0011 on the end of the screw (thrust play)
I hope my "test" is somewhat understandable. Does anyone have another way to check for lost coupler motion?
If I put bearings in and then did the old push and pull technique and came up with no movement in the table but had .0004 backlash when jogging or running a BL program, that would more or less tell me its the coupling or motor, right?
I would like to test the Z somehow but with the weight of the head, I doubt my test would work well.
Thanks, Andrew