Patent ID: 9676062
Date: 2017-06-13
CPC Classifications: B23K

Claim:
1. Process for producing a line of weakness by removal of material in a cover element having a visible side and a back side opposite the visible side, comprising directing laser pulses with an energy determined by a pulse amplitude and a pulse length to said back side and introducing said energy into said cover element repeatedly along an imaginary line at a forward feed speed in a machining cycle so that the line of weakness is formed as a result of removal of material through at least one slit having a slit length and a residual wall thickness of a residual wall adjoining said visible side below said at least one slit, steadily decreasing said residual wall thickness with each machining cycle so that said residual wall thickness becomes sufficiently small that energy portions of the laser pulses which transmit through the residual wall are detected by a sensor arrangement thereby detecting said residual wall thickness, introducing energy point by point along the at least one slit along said imaginary line, said introduced energy being greater in at least one first segment with a first length than in at least one second segment with a second length such that, in each instance, a first residual wall segment thickness of a first residual wall segment of the residual wall along the at least one first segment decreases more quickly than a second residual wall segment thickness of a second residual wall segment of the residual wall along the at least one second segment so that, in each instance, the first residual wall segment thickness of the first residual wall segment along the at least one first segment is detected before the second residual wall segment thickness for the second residual wall segment along the at least one second segment can be detected, and drawing inferences about the second residual wall segment thickness of the second residual wall segment along the at least one second segment without detecting this second residual wall segment thickness.