The most common problem encountered when grinding glass is that the amount of edge chipping exceeds the range, so why does edge chipping occur? It starts with the internal structure of the glass. Modern glass theory includes crystal theory, irregular network theory, polymer theory, pentagonal symmetry theory, gel theory, etc., while crystal theory and irregular network theory are more popular at present.
Jingzi theory focuses on explaining the micro-inhomogeneity and orderliness of the glass structure.
The theory of irregular networks reflects the characteristics of the internal structure of glass that are "orderly in short distance and disorder in long distance".
The two hypotheses are self-contradictory but they can explain the changing laws of the properties of glass. After years of experiments and demonstrations by scientists, the views of the two theories are gradually being consistent. Now the unified view is that glass has a short-range order and a long-range Amorphous substance characterized by disordered structure.
At this point, the answer to why the glass has edges is ready to come out, because the glass has an amorphous and irregular non-crystalline structure, which means that the edges of the glass are inevitable when grinding and processing glass, and it has Randomness. But the unavoidable problem does not mean that it cannot be improved or optimized. The input in the grinding system determines the output effect. The four major input factors are equipment, tools, parameters and workpieces. The occurrence of edge chipping is the result of the combined effect of these factors. Here we focus on discussing methods to improve the control of chipping from the tool.
The characteristics of the grinding head that affect the grinding effect are: diameter, particle size, groove angle, runout (concentricity).
The smaller the diameter of the grinding head, the lower the grinding linear speed, which leads to an increase in the amount of a single abrasive on the sand surface, which increases the grinding force and is prone to edge chipping. Therefore, the diameter of the grinding head should not be too small, and the diameter of the grinding head should be designed reasonably.
The larger the particle size, the smaller the number of abrasive particles on the surface, which also leads to an increase in the amount of a single abrasive during grinding, so that the grinding force becomes greater and the more likely it is to produce edge chipping. In order to effectively control the edge collapse in the required range, the sand size should be selected reasonably. Among them, the choice of fine particle size is particularly important. If the selected sand size fails to meet the product's chipping requirements, it is difficult to process qualified products. Therefore, it should be strictly required to select the appropriate abrasive particle size according to the needs of the product.
The included angle of the finishing groove will affect the amount of edge chipping to a certain extent, because the grinding head will produce compressive stress and shear stress when grinding the glass, and the biggest effect on the edge chipping is the shear stress. Reducing the angle of the groove can The force is biased toward the compressive stress to reduce edge chipping. However, it should be noted that the reduction of the groove included angle will affect the chip removal to a certain extent, so it is very important to control the appropriate included angle.
Concentricity is also the beating size we often say. The greater the beating, the more unstable the grinding head will be, and the number of abrasives involved in the grinding will decrease, resulting in a large amount of grinding of a single abrasive and a large force, resulting in edge chipping The easier it is to produce. Therefore, strict control of the concentricity of the grinding head is also a top priority.
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