Ceramics grinding material removal

The indentation fracture mechanics approach likens abrasive-workpiece interactions for grinding of ceramics to small-scale indentation events. The deformation and fracture patterns observed for normal contact with a Vickers pyramidal indentor under an applied load P are illustrated in Figure 3.1. A zone of plastic deformation is foimd directly imder the indentor. Two principal crack systems emanate from the plastic zone med-ian/radial and lateral cracks. Median/radial cracks are usually associated with strength degradation and lateral cracks with material removal. 

Most past research on grinding mechanisms for ceramics has followed either the indentation fracture mechanics" approach or machining" approach. The indentation fracture mechanics approach would seem to offer the possibility of describing both the material removal process and its influence on strength degradation in terms of the force or depth of cut at an... 

Kirchner, H.P. and Conway, J.C., 1985, Mechanisms of material removal and damage penetration during single point grinding of ceramics. Machining of Ceramic Materials and Components, ASME, New York, Vol. 17, pp. 53-61. 

Imanaka, A., Fujino, S., and Maneta, S., 1972, Direct observation of material removal process during grinding of ceramics by micro-flash technique, in... 

Tonshoff, H.K., Telle, R., and Roth, P., 1990, Chip formation and material removal in grinding of ceramics, 4th Int. Grinding Conf, SME Technical Paper MR90-539. 

It is well known that the material removal mechanism in the grinding of ceramics is mainly a brittle fracturing process and grinding induced damage in terms of microcracks has been observed in various ceramics. Ceramic materials are very sensitive to cracks due to their low fracture toughness. The principal induced crack systems are the lateral cracks and the median cracks. The lateral cracks are parallel to the ground surface, and the median... 

To optimize the process parameters for belt centerless grinding of ceramic materials and hardened tool steel. Our preliminary trials focused on the relationship between process parameters, belt speed and through-feed, and several output parameters depth of cut, stock removal, material removal rate (MRR), and surface roughness. 

Material Removal Mechanisms in Grinding of Ceramics and Glasses... 

Zhang, B. and Howes, T.D., Material-removal mechanisms in grinding ceramics. Annals ofCIRP, Vol. 43, no. 1,1994, pp. 305-308. 

ABSTRACT A double side grinding (DSG) computerized kinematical model accoimting for piece rotation inside its slot into the carrier was developed. Trajectories for representative points located on the end faces of the workpiece were simulated. A radial wear gradient of the active surface of the wheel was predicted. Experiments accomplished with different wheel specifications, process parameters, operation duration, and coolant types were carried out. A strong correlation was foimd between the predicted length of the trajectory of a specific point located on the piece surface and the experimental material removal rate. A radial wear gradient was experimentally confirmed. Conclusions on optimizing the DSG process for advanced ceramics with diamond were drawn. 

Heating ceramic materials before grinding aids the material removal process. In the four ceramic samples, the surface quality was also improved. 

The mechanism of material removal in abrasive machining of brittle ceramics has been well documented by Evans and Marshall who developed the lateral-crack chipping model. They demonstrated that material removal rate, AT caused by a passage of each grinding particle is related to the peak normal penetration forces, Fn, Vicker s hardness and fracture resistance as follows, ... 

The greatest amount of material removal is achieved with bonded diamond grinding disks. Progressively lower rates of removal are associated with polycrystal-hne diamond suspensions, monocrystalline diamond suspensions, diamond sprays, diamond pastes, SiC papers, and AI2O3 slurries (in that order). However, as the rate of material removal increases, so does the amount of damage caused to the sample smface. In the case of relatively soft or porous ceramics, it can be practical to use an... 

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