Pencil manufacturing method, involves forming raised structure where surface area of circular cylinder-shaped plastic shaft is treated with laser beam such that plastic emerges out from surface area under volume increase

摘要

The method involves forming a raised structure (4) where a surface area (3) of a circular cylinder-shaped plastic shaft (1) is treated with a laser beam such that plastic emerges out from the surface area under volume increase. The shaft is made of plastic material, which foams during heating the plastic material with the laser beam, where the shaft contains a laser light activatable blowing agent. An expanding substance e.g. blowing graphite, is used as the blowing agent. Foreign molecules are stored between carbon layers.