Murdered Fiat
Plastic
- Joined
- May 27, 2019
- Location
- Ontario
Hello all, I'm a new member of the forum, but have been visiting for years to find solutions to some problems. Hope you folks can help me out again.
I've attached an image of a recent ball bar test we had done to our Tos WH10. I did not arrange to have the test completed, nor do I fully understand it. My boss arranged it and is now asking me what the results mean. Hopefully you can clarify some things for me.
Looking at the values:
Backlash:
X has unequal backlash - damage or wear to x-axis drive components. Likely the case here as this machine is 20 years old and has a lot of hours on it.
Y backlash is relatively equal and minimal, not really a concern.
Reversal spikes:
X large reversal spikes - damaged or binding of moving axis components, inadequate lubrication, bad ball screw and or bearings
Y Not as bad as X (Y ways were recently reground and headstock was machined and tourcited). Ball screw problems?
Lateral play:
I don't know what this is telling me...
Cyclic error:
X and Y - Ballscrew and drive problems - more of the same information as reversal spikes?
Servo mismatch:
Time in milliseconds that one axis servo leads another. This is why forward and reverse runs are mirrored? Drives need to be tuned if possible?
Squareness: Actual squareness of X to Y in both vertical and horizontal planes? Level check of Y-X travel showed 0.005mm Y+...
Straightness: How straight the axis is, nothing to do with level or square?
Scaling error: How much error there is in the scale per meter. How is this corrected?
Positional tolerance:
191.3µm... holy! does this mean the machine doesnt have positional tolerance of 191µm over the 300mm radius of the test, or over 600mm? Is this a combination of all the errors? or what does this relate to?
Best fit radius: Basically the average sized circle that fits the data. But what does that mean? Wouldn't least square circle tell you better information ie. positional?
Circularity: difference between largest and smallest radius measured by the ball bar. 152µm... that's a lot but what does it really mean?
This is a really long winded first post. I'm very sorry. I hope I have posted in the right thread and I thank everyone for taking the time to read.. and hopefully respond.
Thanks
Zac