One of the leading German manufacturers of eyeglasses needed a system for incoming raw lens inspection that could test the coating of eyeglass lenses for tension, pressure and abrasion. The test is partially specified in a DIN/EN standard.
The requirement was a parameterizable solution to increase the flexibility of the system. That’s why dialogue control became necessary. In addition, the system should be compact and closed. The safety technology was mandatory.
Here you can see the three test options:
(from left to right abrasion test, tensile test, pressure test).
Abrasion test:
First, the glass is fixed on a rubber lip with a vacuum. In the standardized test, a cylinder performs a lifting movement, which is limited by adjustable sensors. The pressure force is exerted by a special device within a tolerance range of ± 1 Nm. The number of strokes can be set using the Siemens dialog control.
Pull test:
In the test carried out by the customer in addition to the standard, the blocker is stuck to the coated surface using the adhesive pad. A tension spring with a permanent display is attracted by a pneumatic cylinder. The pull-off force can be read on the standardized spring balance.
Pressure test:
The glass is placed in a specially made device on a standardized test ring. A pneumatic cylinder, which, in cooperation with the calibrated pressure can, exerts a previously defined pressure, presses onto the lens via the measuring mandrel. The maximum pressure exerted, possibly until the glass breaks, can be read in Newtons on the load cell.
