Materials for precision machining are divided into two categories, metal materials and non-metallic materials. For metal materials, the hardness of stainless steel is the largest, followed by cast iron, followed by copper, and finally aluminum. The processing of ceramics and plastics belongs to the processing of non-metallic materials.
For the requirements of material hardness, for some occasions, the higher the hardness of the material, the better. It is only limited to the hardness requirements of the processing machine parts. The processed materials cannot be too hard. If they are harder than the machine parts, they cannot be processed. The material is moderately soft and hard, which is at least one grade lower than the hardness of the machine parts. At the same time, it also depends on the function of the processed devices and the reasonable material selection of the machine parts.
Therefore, before processing, we must pay attention to the density of the material. If the density is too large, it is equivalent to a great hardness, and if the hardness exceeds the hardness of the machine part (lathe tool), it is impossible to process, which will not only damage the parts, but also cause danger, such as the lathe tool flying out and hurting people. Therefore, generally speaking, for mechanical processing, the material quality should be lower than the hardness of the machine tool, so that it can be processed.
