How to solve common problems in polishing (1)

1) Over polishing

The biggest problem encountered in the daily polishing process is "over-polishing", which means that the longer the polishing time, the worse the quality of the mold surface. There are two phenomena of over-polishing: "orange peel" and "pitting". Excessive polishing occurs mostly in mechanical polishing.

2) Reasons for "orange peel" on the workpiece

The irregular rough surface is called "orange peel". There are many reasons for "orange peel". The most common reason is that the mold surface is overheated or carburized. The polishing pressure is too large and the polishing time is too long. The main reason for "orange peel". For example: polishing wheel polishing, the heat generated by the polishing wheel will easily cause "orange peel". Harder steels can withstand greater polishing pressure, and relatively softer steels are prone to over-polishing. Studies have shown that the time for over-polishing will vary depending on the hardness of the steel.

3) Measures to eliminate "orange peel" of workpieces

When the surface quality is found to be poorly polished, many people will increase the polishing pressure and prolong the polishing time. This practice often makes the surface quality worse.

The following methods can be used to remedy:

1) Remove the defective surface, and the grit size is slightly coarser than the previous sand size, and then the grinding is carried out, and the polishing force is lower than the previous one.

2) Perform stress relief at a temperature lower than the tempering temperature of 25 ℃, use the finest sand number to grind before polishing until a satisfactory result is achieved, and finally polish with a lighter force.

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