Sometimes when foam laps are used, cutted on the SGX, the curve of the lap is off. I has been wondering if the SGX is as precise as it should be.
Since a foam lap can not be measured with the sagometer i decided to cut the lens and the lap in the SGX (same curve) , fine the lens using this foam lap (in the cylinder machine) and measure the sag of the concave curve of the lens. If the lap is right, the lens should have the sag that Innovations print in the ticket if the option (Setting Navigator - Method - Standard - Workticket -"Print lens back curve sags on summary page") is marked.
In my case, most of the time the lap foam is wrong. I have not tried plastic laps yet but i suspect that they would also come wrong because i think the problem is with the SGX and not the lap material.
We have that problem no matter if the cutter is new or used or if we have just calibrated the SGX or not. (White disc).
I would really appreciate if someone that has a SGX try this to see if he has the same results. Try low curve (under 3.00) that is where i has seen a greater problem. In my case the lap may be off curve up to 0.12. The problem seems to be worst in the base curve than in the cross curve of the lap.
Thanks in advance
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