Borosilicate glass and single crystalline silicon foils were bent by laser forming. Because these materials are brittle at room temperature, it is necessary to form them plastically at a high temperature. In this study, it was easy to heat foils by laser irradiation. In the case of forming borosilicate glass foils, a resistant heater was used accessorily to heat the foils. A 20 W Q-switch pulsed YVO4 laser was employed at a frequency of 200 kHz. Bending angles were investigated by changing laser power, scanning velocity, and defocus length. From the experimental results, in the case of forming borosilicate glass foils, the bending angle became larger when the laser power was 12 W, scanning velocity was smaller and defocus length was 8 mm. In the case of forming single crystalline silicon foils, the bending angle reached the maximum when the laser power was 13 W, scanning velocity was 15 mm/s, and defocus length was 5 mm. Multiple laser scanning at a constant scanning pitch was also carried out for borosilicate glass foils, and the foils were bent into partially cylindrical shape.

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We investigate the imprinting ability of microgrooves in form-rolling metal shafts. A reciprocating form-rolling testing machine specialized for form-rolling microgrooves on metal shafts is newly designed and constructed. The shafts used are made from austenitic stainless steel SUS303 and aluminum alloy A5056 and have a diameter of 9±0.005 mm. The testing machine is equipped with a couple of flat dies that have a row of straight projections 10 μm high and 500 μm wide. The gap between the dies is set at a resolution of micrometer order. The imprinting ability of microgrooves onto the specimens is observed in detail by varying the nominal indentation ratio from 1.5 to 9 (the ratio of the amount of die indentation to the height of projection). Finite element simulations are also carried out. The calculated profiles of form-rolled specimens are compared with the observed ones in detail. In order to accurately reproduce the geometry of microgrooves form-rolled on metal shafts, it is crucial to predict the indentation ratio for the metal shafts as accurately as possible. This is achieved by properly assessing the elastic deformation of the form-rolling machine.

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