Lapping agent

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Lapping abrasive or lapping powder are abrasive , which the lapping of workpieces are used. As cutting grains, they are unbound in a carrier medium during the process.

Materials with a low density have proven themselves as lapping agents . Lapping agents with high density, for example corundum (density: 4 g / cm³), are less suitable because they cause rapid sedimentation .

Examples

• Green silicon carbide - a hexagonal crystal shape - density 3.21 g / cm³ - not as a fragment - is used for processing glass and softer materials.
• Silicon carbide gray / black - splinters earlier and is less suitable for ultrasonic machining because the grain size decreases relatively quickly, which changes the size of the gap and thus the resulting bore diameter. Mainly grains between 280 and 400 mesh are used .
• Boron carbide - a tetragonal crystal form - density 2.51 g / cm³ - is the most commonly used type for ceramic processing. The material is usually used until the suspension is enriched with removed material and has to be replaced. The removal rate for glass is slightly lower due to the larger wedge angle of the cutting edges (approx. 120 °), but the service life is much longer. There is no tendency for the grains to break. Only when machining spinel , ruby or silicon nitride does higher grain wear occur due to the dulling of the grain edges. Mainly grains between 250 and 400 mesh are used. The standard grain size is 280 (approx. 40 µm).
• Diamond and CBN (cubic boron nitride) are mainly used for machining diamond and PCD (polycrystalline diamond) because of the high procurement costs . The service life depends on the machining task.