ROTARY TOOL FOR SHAPING A FORM IN A MINERAL MATERIAL, SUCH AS SAPPHIRE, AND, IN PARTICULAR, FOR SHAPING AN OPTICAL SURFACE IN A WATCH CRYSTAL

摘要

The invention relates to a rotary tool (20) which is used to shape a form in a mineral material, e.g. a hard mineral material. The inventive tool consists of a body having a head (20a) disposed at the end thereof, said head comprising an active surface (200) which is intended to come into contact with an area of the mineral material where the form is to be shaped. The head of the tool is equipped with at least one first slit (210, 220) which opens onto the aforementioned active surface in order to form an opening (210a, 220a) thereon which allows abrasive particles conveyed to the area to be lodged thereon and to form a cutting edge along the length of said opening, which is used to form the desired shape. Said tool is particularly suitable for forming a distorting optical surface (e.g. a lens) in a hard, transparent mineral material such as sapphire, corundum or spinel, for example, in a watch crystal. The invention also relates to a method of forming a shape in a mineral material using the above-mentioned tool and to a machining installation comprising one such tool.