Abstract
An improved method for piercing a circular hole in a glass sheet, difficult to achieve by conventional punching or drilling, is investigated by employing a manufacturing process using the impact compression of a viscoplastic pressure medium. Since the method previously proposed by the authors is not appropriate for a large ratio of hole diameter to workpiece thickness, an improvement is attempted in which two techniques are proposed: a method based on the delay phenomenon in the elastic response of workpieces and a differential pressurization method. Results show that both methods are useful. The latter method is also effective for improving the accuracy of the produced hole.
