Sharpening of Metal-cutting Tools

Sharpening of Metal-cutting Tools

 

a final operation in the manufacture of tools; also a method of restoring the cutting ability of tools during use. The sharpening cycle consists of grinding and finishing (honing). The basic requirements of the sharpening operation are the production of the optimum configuration of the cutting part of a tool and the minimum roughness of the surface and cutting edges. Sharpening is done on ordinary grindstones or on grinding machines with polishing wheels. Electric-spark and anode-mechanical methods are also used.

Electric-spark grinding of a tool is done in a dielectric bath. The metal machining disk and the tool being worked are connected to different poles. The high-power spark discharge that occurs between them fuses the tool surface and reduces its roughness. Anode-mechanical grinding is done in an electrolyte. The tool is connected to the positive pole, and the grinding disk is connected to the negative pole. Upon simultaneous actuation of the electrolyte and the rotating disk, a protective anode film is formed on the tool surface and smoothes over the roughness. Electric-spark and anode-mechanical sharpening provide high surface quality and straightness of the cutting edges without the use of an abrasive tool. However, these methods are not as efficient as mechanical methods. The most promising and efficient method is the use of diamond polishing tools—metal disks charged with fine diamond particles.

V. V. DANILEVSKII