Breviary Technical Ceramics


      From Powder to Part

 Honed surfaces

The overlaying of a large number of fixed-force scraping movements of cutting grains over the material, involving wide-area tool contact and a primary active direction parallel to the surface of the workpiece are characteristic of honing. The cutting speed involved in honing is perhaps an order of magnitude lower than that used for grinding, which means that thermal effects are comparatively small. As a result of this, honed ceramics surfaces generally do not display any signs of fusion or thermally induced cracks. As with grinding, both ductile and brittle material separation mechanisms occur next to one another. The penetration depth of the cutting grains and the cutting speed are the primary factors influencing which of these mechanisms will be dominant.

Figure 69: Surface generation depending on the cutting grain size, D, and
the contact pressure, ps, when honing aluminium oxide

Higher cutting speeds have a positive effect on the rate at which material is removed when honing with brittle cutting. Higher cutting speeds are, however, are a disadvantage for the surface quality due to the increased tendency to induce cracks that lead to break-outs and spalling.


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