As an important part of the automobile braking system, the brake disc plays a role in safety protection during driving. Its quality is directly related to the safety of the driver's life and property. Therefore, the processing technology and tool selection for manufacturing brake discs are particularly important. This article aims to introduce the selection techniques of CNC vertical lathe roughing and finishing tools for turning brake discs, and to help the machining shop choose the optimal solution.
1. Brake disc material selection
First of all, the material of the brake disc is the primary factor affecting the choice of tool. The most commonly used materials in the brake disc manufacturing industry are gray cast iron and steel. Gray cast iron brake discs have poor heat resistance at high temperatures and are prone to thermal cracking. Steel brake discs are not prone to thermal cracking, but have relatively high hardness and will shorten the life of the tool. Therefore, when selecting tools, different choices should be made according to the brake disc material and material processing status.
2. Tool selection rules
Tool selection is one of the complex issues in CNC machining. It must be comprehensively analyzed from the hardness of the tool, the hardness of the processed material, cutting force and other factors. Especially in finishing and roughing, the tool selection rules are also different.
In the roughing stage, tools with high hardness and toughness should be used to facilitate rapid cutting and make full use of tool life. In the finishing stage, it is necessary to select tools with relatively low hardness and good coating to obtain good surface quality.
When choosing different types of tools, please refer to the following rules:
1) In the roughing stage, tools with larger cutting edge lengths should be selected to facilitate rapid cutting and make full use of tool life.
2) Choosing a tool with a large radius and a small rake angle can increase the cutting area, improve cutting efficiency, and reduce the risk of tool samples.
3) The toothed tool has good rigidity and good stability during use, and is suitable for cutting at higher speeds.
4) For the finishing stage, coated processing tools can be used to obtain good surface quality.
3. Tool coating selection
The choice of coating greatly affects the service life of the tool. Generally, coating materials are divided into two categories: non-polycarbon coatings and polycarbon coatings.
Compared with polycarbon coatings, non-polycarbon coatings are less hard, but have better wear resistance. At the same time, most of the coatings have a single structure, so there is no excess stress during the processing, and the coating is released relatively quickly, which will not affect thermal deformation during the processing.
Polycarbon coatings incorporate carbon nanotubes into the coating. Carbon nanotubes have physical properties similar to graphite, and the close-knit structure formed with the material is beneficial to the bonding force between the coating and the material surface, thereby extending its service life. In addition, the polycarbonate coating can reduce friction during cutting, improve cutting efficiency and surface roughness.
In summary, choosing the appropriate CNC vertical lathe roughing and finishing tool is of great significance in brake disc processing. The selection should be based on the brake disc material and material processing status, and a comprehensive analysis should be conducted in conjunction with the coating selection rules. This can improve cutting efficiency and processing quality, and also reflects the rationalization of the process flow.