We are using Satisloh PRA blocker since 7 years. Recently our surfacing technician has come up with a compliant that lens power variation is due to low temperature of the blocking ring area(blocking station). Then we have done the experimental process for two days as follows.
- First day with very low temperature-near to zero degree, we have blocked more than 200 lenses.. that day we have got the power rejection in 2 lenses(not sure if it is due to the low temperature)
- Second day we set the blocker station temperature to normal, same quantity of lenses have been blocked then we have got the power variation in 4 lenses.
Still my doubt is not cleared, is it really possible that powers can change if the blocking station temperature is very low !!!?
I know if we increase the alloy temperature more than the required, there is a chance to get the curvature changes in lenses. But decreasing the temperature...!!!??
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