Angličtina
Current techniques for mechanical working of ordinary materials like steels and cast iron are highly developed and machine tools have been greatly improved in recent years. Recent years have seen the introduction of many new materials such as tungsten and titanium carbide, diamonds, rubies, sapphire, hard steels, magnetic alloys and corundum. Another group of material, germanium, silicon, ferrites, ceramics, glass etc give difficulty on account of great brittleness: these materials often cannot withstand the forces needed for machining. Modern materials such as high-strength steel and ceramics, which are developed to meet the needs of advanced industries, are typically string, hard and brittle. Whilst technologically desirable, these characteristics often render the material difficult and sometime impossible, to shape by machining processes into useful components and parts. The cutting action imposed by above said machining processes on brittle materials, for example, will yield components with very poor surface finish and in many cases, results in the chipping and/or fracture of the materials being machined.
