The term 'Fabrication' applies to operations, such as: cuttings, stamping and punching of natural sheet mica to specified size, shape, thickness and design within close dimensional tolerance for electrical and electronic end-users.
Normally, mica is fabricated with compound dies by foot or power punch process, especially if the finished piece contained perforation of any kind. A compound die punches the outside shape and all the inside holes with one stroke of the press most accurately. The compound die necessary for stamping natural sheet mica may be grouped in two general categories. One category comprises the highly complex dies required to produce Mica Spacers containing a number of perforations in various sizes and shapes for use in electronic tubes. The extremely critical dimensions and spacing of the perforations can be obtained only with fully designed and accurately constructed dies.
The natural structural stability in mica renders it the perfect dielectric with outstanding features of low leakage, great stability under increasing temperature, high insular strength, low rate of solar impurities and reasonable admittance factor. Because of these outstanding features, mica is most suited for use in thermionic valve bridges, cathode ray tube assemblies, condenser plates, domestic elements, stove plates and washers built upto any thickness. In almost all these applications, mica is die-punched and used as such, or with a coating.