O-inspect Dotscan

[[Cl...]]

We have a 543 O-inspect with Dotscan. We run a master part daily. About once a month on average
two particular dimensions on the master part fall out of tolerance. Both dimensions are measured with
the dotscan.

After re-qualifying the dotscan and Running the master part again, those dimensions are now good.
There were no collisions. All sensors are qualified every Monday. Just wondering if anyone else has
experienced this?

[[Ch...]]

OIs are very temperature sensitive machines. My guess here is that the XYZ offset between the tactile probes (MasterProbe) and the DotScan is changing throughout the week due to temperature. When you requalify the DotScan, that resets that XYZ offset relationship between the XXT and DotScan thus meaning you are good to go until that temperature shift occurs again. I think the question here would be does your temperature remain constant in the room and do you leave the OI running all the time so that the internal temperature of the machine also remains constant? If both are true and you still are seeing abnormal shifts in results on the gage can I ask what type of dimensions are you checking and are both Tactile and DotScan sensors used in these failing dimensions? How much are they out by typically?
Another common reason for seeing a shift like this is if every weekend the OI is shutdown and thus it cools down. Then come Monday the OI is started up and requalified. However OIs have a warmup time of 5 hours if fully shutdown for an extended period of time thus meaning no qualifications or measurements should be taken until the 5 hour warmup period has passed. Where some users get themselves into trouble is they qualify before the warmup passes and thus the OI continues to heat up after qualification changing the XYZ relationship between the XXT and DotScan leading to an offset. Qualifications need to be done after the 5 hour warmup has passed to avoid this issue. (Not saying you are doing this but want to throw it out there). Hope this helps.

[[Cl...]]

Thanks Charles. That makes sense as a re-qualification corrects the issue.
I don't know off hand how much it's out by. I'll find out. The machine is kept on always.

[[Ch...]]

Sounds good. Since the OI stays on all the time forget what I said about the 5 hour warm up 🙂

Technically for an OI 543 room temperature variations must not exceed 2°F/day and 1°F/hour.

If the amounts are out by a significant amount and the temperature in the room meets the mentioned criteria it may be worth while to have a conversation with ZEISS hardware support to get their view on the matter.