Why do glass diamond grinding wheels crack?

The following factors may contribute to glass diamond grinding wheel grinding cracks: the workpiece's surface stress exceeds the limit of fracture; in other words, the workpiece has residual mechanical and thermal stress on its surface from before grinding or heat treatment. Due to the part being ground just to keep the balance of stress, the residual stress is greater than the workpiece's strength, resulting in a grinding crack.

Cracks are the solution to the problem for all of these reasons. The most serious issue is the tension caused by grinding heat. Because the grinding heat rapidly raises the local temperature of the workpiece surface, this item will be tempered or undergo other heat treatment. Tensile stress causes fractures to form due to changes in the interior structure and shrinkage of the surface.

Changing the feed rate of the glass diamond grinding wheel yields the residual stress after grinding:

1. The greater the feed rate of the glass diamond grinding wheel, the deeper the residual stress is.

2. At the same time, the surface residual stress acts as tensile stress in the grinding direction, but also as pressure acting on the vertical direction of the grinding direction, and the deeper to the inside, the stress is lowered dramatically.

3. When acting in the grinding direction and vertical direction, it first generates compressive stress, then abruptly becomes tensile stress in the grinding direction. When it reaches its maximum, it gradually lowers to become a little compressive stress.

The feed-to-residual-stress relationship of a glass diamond grinding wheel:

1. Tensile stress will gradually increase as the grinding wheel feed force increases, eventually approaching the tensile strength of the workpiece material. Cracks will form when the workpiece's tensile strength exceeds the material's.

2. Because the scale and different experimental conditions cannot be compared, the compressive stress will be practically unaltered if the cutting depth is 0.05mm, the highest residual tensile stress, although cut deep residual tensile stress is not too large. This is often assumed to be the source of abrasive wear.