hexagon logo

Change in accuracy from reducing pre-hit distance?

I’ve been trying to reduce CMM runtime in our QC department and I’ve found that using fly mode and reducing the pre-hit/retract distance by half, it cuts an average of 13% off the runtime for our product. I’m trying to make this a standard, so I want to show my time studies to management. Before I do, I wanted to make sure there were not any changes in accuracy.

From what I know, the only downfall to shortening the pre-hit distance from .1 to .05 is if measuring a non-consistent part like a cast part, the probe might move to close before taking a hit and throw an error when it touches the part. I also know it shortens the distance it will search past the theoretical point, but that can be adjusted by setting the check distance, right? So, is there any other reason you wouldn’t want to shorten the pre-hit distance?
Parents
  • I would say that retract distance as no effect on accuracy, because the coordinates are taken.
    For the prehit, I think that it's a "time" for stabilization of the dynamic move (decceleration) of the bridge, so using a too small distance could affect the accuracy. Here, you purpose to use 1.27 mm, I think it's ok.
    As usual, it's important to use the same speed during measurement and calibration. Depending on the probe, but maybe you could win a little more by changing the speed, without loosing too much accuracy.
Reply
  • I would say that retract distance as no effect on accuracy, because the coordinates are taken.
    For the prehit, I think that it's a "time" for stabilization of the dynamic move (decceleration) of the bridge, so using a too small distance could affect the accuracy. Here, you purpose to use 1.27 mm, I think it's ok.
    As usual, it's important to use the same speed during measurement and calibration. Depending on the probe, but maybe you could win a little more by changing the speed, without loosing too much accuracy.
Children
No Data