Breviary Technical Ceramics


      From Powder to Part

 Polished surfaces

According to DIN 8589, polishing is not an independent production process, and is only used in association with other manufacturing processes. Processes such as polish grinding, polish honing, polish lapping, electrolytic polishing and polishing through coating (the application of polish with mechanical treatment) are distinguished. Polishing is primarily intended to create a high quality of surface. In contrast to lapping, the polishing grains are embedded in a cloth or polishing wheel so that directed tool movement, which is necessary to create optically reflective surfaces, is achieved. Because of the low rate of material removal, polishing is time-consuming.

Slight plastic deformation is only normally achieved in ceramic machining through extremely high localised pressure. For this reason, the removal of material when polishing ceramic is explained through scratches involving cutting depths in the range of nanometres. Polished surfaces are characterised by smooth areas and hollows, depending on the polishing time and the polishing grains used. Other surface characteristics are only occasionally met, and are not typical.

Figure 72: Silicon carbide surfaces polished with 9 ?m and 0.25 ?m polishing grains


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