Grinding Mechanisms for Ceramics

Grinding damage assessment on four high-strength ceramics

“…3Y-TZP (Lava) sintered bars of 3 × 5 × 40 mm 3 were provided by the manufacturer and broken in halves to obtain matching pairs. In-Ceram AL, In-Ceram ALUMINA and In-Ceram ZIRCO-NIA were cut from CAD-CAM presintered blanks using a low speed rotatory fine cutting diamond disk under cooling water in an ISOMET machine (Buehler).…”

“…Such reshaping procedure performed both by the laboratories and sometimes the dentist may have some critical mechanical consequences depending on the diamond bur grit used. As ceramics are intrinsically brittle and their mechanical properties largely influenced by their surface state, their flexural strength can be negatively affected by every treatment that increases surface roughness with the introduction of surface or subsurface flaws [2,3] that may be subjected to tensile stresses. The damage process during grinding of ceramics by an abrasive particle has been described with the formation of mainly two types of cracks: parallel cracks (long or short semi-elliptical) formed parallel to the direction of grinding, or short orthogonal cracks perpendicular to the abrasive motion direction [2].…”

“…The damage process during grinding of ceramics by an abrasive particle has been described with the formation of mainly two types of cracks: parallel cracks (long or short semi-elliptical) formed parallel to the direction of grinding, or short orthogonal cracks perpendicular to the abrasive motion direction [2]. Tangential forces may also apply during grinding which tend to increase tensile stresses normal to the direction of motion, favoring median crack propagation in the plane of motion [3].…”

Cerâmicas avançadas no processo de retificação cilíndrica externa de mergulho utilizando a técnica da mínima quantidade de lubrificação (MQL) com rebolos diamantados

“…Zona plástica e formação das trincas médias/radiais e laterais devido ao riscamento por um grão abrasivo [7].…”

“…O consumo de óleo neste método é reduzido, definido entre 10 e 100 ml/h, já que o mesmo conta com o desempenho refrigerante do ar comprimido. Outro aspecto positivo deste sistema se concentra no fato da mistura coaxial de refrigerante e ar no bocal previnir em grande escala a nebulosidade [7,17,18].…”