For precision parts processing, not all materials can be precision processed. Certain materials with excessive hardness exceeding the hardness of

 the machining parts may damage the parts. Therefore, unless these materials are machine parts made of special materials or laser cutting, they 

are not suitable for precision processing.

The materials for precision parts processing are divided into two categories, metallic materials and non-metallic materials.

Generally speaking, stainless steel has the highest hardness, followed by cast iron, followed by copper, and finally aluminum. The processing of 

ceramics and plastics is the processing of non-metallic materials.

1. The first is the requirement of material hardness. For some occasions, the higher the material hardness, the better. Only limited to the hardness

 requirements of the machined parts, the processed material should not be too hard. If it is harder than the machine part, it will be unable to be

 processed.

2. Secondly, the material is moderately hard and soft, at least one grade lower than the hardness of the machine. At the same time, it also depends 

on the purpose of the processing device, and the rational selection of the machine parts.

In short, precision machining still has some requirements for materials, and not all materials are suitable for processing. For example, for materials

 that are too soft or too hard, the former is not necessary for processing, while the latter cannot be processed.

Therefore, the most basic one is to pay attention to the density of the material before processing. If the density is too high, the hardness is also

 great, and if the hardness exceeds the hardness of the machine (lathe tool), it cannot be processed. Not only will the parts be damaged, but it will

 also cause danger, such as the turning tool flying out and hurting people. Therefore, in general, for mechanical processing, the material material 

must be lower than the hardness of the machine knife in order to be processed.

There are many mechanical processing methods, and each mechanical processing method requires technological requirements. According to the

 basic processing methods of mechanical parts, such as material, bending, stretching, forming, and welding, we must Pay attention to their process

 requirements.

According to the different processing methods, the blanking can be divided into general punching, number punching, shear cutting, laser cutting,

 and wind cutting. Due to the different processing methods, the processing technology of the blanking is also different. The mechanical cutting 

methods are mainly digital punching and laser cutting. The advantages of laser cutting are that the thickness of the processed plate is large, the

 cutting speed of the workpiece is fast, and the processing is flexible. The disadvantage is that it cannot be processed at one time, and mesh parts

 are not suitable for processing in this way, and the processing cost is high.

The welding methods of mechanical processing plants mainly include arc welding, plasma arc welding, gas welding, pressure welding, fusion

 welding, electroslag welding, and brazing. The welding of mechanical products is mainly arc welding and gas welding. Arc welding has the 

advantages of flexibility, mobility, wide applicability, all-position welding, simple equipment, good durability, and low maintenance costs. 

However, the labor intensity is high and the quality is not stable enough, which depends on the level of the operator. The temperature and 

properties of the gas welding flame can be adjusted, and the heat source of arc welding is wider than the heat affected zone, the heat is not 

as concentrated as the arc, and the productivity is low.