During the flat grinding process, without the use of coolant, the hardness of the workpiece surface layer will sharply decrease and the surface layer will be annealed. Under the condition of rapid cooling with polishing fluid, the workpiece surface will quench and burn during the grinding process. If the surface temperature of the workpiece exceeds a certain range, rapid burning will occur.
During the planer grinder processing, as the primary function of the abrasive particles is to cut, scrape, and slide, most of the abrasive particles are cut off. This results in the workpiece surface reaching high temperatures during high-speed grinding. Under the influence of higher temperatures, the microstructure of the workpiece surface will undergo significant changes, which will alter the surface hardness of the workpiece and ultimately affect its performance.
Simultaneously, due to the varying color of the oxidation film on the workpiece surface, the nature of grinding burns is the change in the material structure of the workpiece surface. This is primarily because the temperature in the processing area is high. When the surface temperature of the workpiece reaches a certain level, scorching is more likely to occur.
To observe the process of surface combustion of workpieces, it is necessary to measure the average surface temperature of the workpieces at different stages. This test plays a crucial role in solving combustion control and prediction issues during production. It has been proven that burnishing is a gradual process. In planer grinders and polishing machines, temperatures will change, and the processing temperature will be completed in a short period. It may rise. It should be noted that the temperature here will change immediately. Essentially, it reflects in the stepwise change of temperatures on both sides, and they are the same. There are some issues in determining the burn change if only the temperature change at that point is reflected.
As the surface temperature of the workpiece gradually increases from low to high, and reaches or exceeds the combustion temperature of the workpiece material, surface burns on the workpiece begin to appear.
The primary cause of burns is the high grinding temperature. Burns are mainly related to temperature. Due to many factors affecting the workpiece temperature, burns are somewhat influenced. If workpieces with poor combustion properties are more likely to burn during combustion, both burns and sandpapers will be affected. If the sandpaper is too hard, it lacks self-sharpening and can cause scorching, so a soft sandpaper is needed to reduce scorching; coarse sandpapers are less likely to ignite. Improving heating time and heat dissipation conditions can have a certain impact on severe burns. Properly cooling the slurry after it has been fully cooled is very beneficial in preventing burns and cracks.
