We're having a rash of prism. I suspect our autoblockers. Current SOP is to run hourly test trays, inspect at QC. If they fail we calibrate. Turn around time is an issue, as well as accuracy at QC.

I acquired DACs Prism Detector Tools Item DV-PR-DT) from a dusty drawer. I like the idea of changing our SOP to take direct measurements of the blocking ring, not relying on a 65-75 minute turn around and a subjective lensometer reading.

I'm having difficulty translating our tolerances to the dial indicator reading of the measurement surface of the prism detector ring. I have the dial indicator set to sweep a 60mm diameter of the prism detector tool.

I meticulously calibrated a blocker. Blocked up the test lens and swept across it with the indicator. Setting the low point to 0.00 it went up to just a hair over 0.01. Recalculated the job to block 0.12dpt in OU. Swept it with the indicator and it swung 0.00-0.24.

Can someone help me derive whether this is accurate? Or can share their SOPs with this tool?

Thank you.