Polishing refers to a processing method that uses mechanical, chemical or electrochemical actions to reduce the surface roughness of the workpiece to obtain a bright and flat surface. Manual polishing can not improve the dimensional accuracy or geometric shape accuracy of the workpiece, but aims to obtain smooth surface or mirror luster, and sometimes it is also used to eliminate luster (extinction).
There are many kinds of hand polishing materials, generally divided into: polishing wax, polishing cloth wheel, nylon wheel, hemp wheel, wire wheel, wind wheel, miscellaneous cloth wheel, etc.
Different workpiece polishing has different polishing processes, and different processes require different polishing consumables. The traditional manual polishing process is divided into three processes: coarse polishing, semi fine polishing and fine polishing. Today, with the rapid development of polishing technology, the manual polishing process has also been rapidly developed and improved, shortening the polishing process to two processes, and even some workpieces can be fine polished in one process.
Take the polishing of hand plate aluminum alloy handicrafts as an example, there are two commonly used methods for polishing aluminum alloy. They are acid polishing and alkaline polishing. Hand polishing is nothing more than to get a smooth and flat surface of the workpiece, which is a method of hand surface treatment. Different polishing methods have their advantages and disadvantages.
Take the chemical polishing and electrochemical polishing of aluminum alloy alkaline polishing as an example:
1. Alkaline chemical polishing:
Advantages of aluminum mirror polishing and aluminum alloy polishing: It is applicable to all kinds of aluminum and aluminum alloys, and can also obtain satisfactory results (aluminum base color and luster) for cast aluminum and die-casting aluminum (with low impurity content and sand blasting treatment). No nitric acid, no Huanglong pollution.
Disadvantages: It has a large amount of aluminum dissolution and general gloss, and is not suitable for precision parts and parts with mirror gloss requirements
2. Electrochemical polishing
Advantages: no hexavalent chromium pollution, low cost, and mirror luster.
Disadvantages: The process is complex, requiring rectification power supply, fixture and anode moving device.