In the process of machining, it is often difficult to process with standard tools, so it is very important to manufacture non-standard tools. Since the use of non-standard tools in metal cutting is common in milling, this paper mainly introduces the manufacture of non-standard tools in milling.
Since the purpose of manufacturing standard tools is to cut a large number of general metal and non-metal parts in a large area, when the workpiece is overheated and hardened, the workpiece is made of stainless steel, and the cutting edge is very easy, and there is also the surface of the workpiece. When the geometry is very complex or the roughness of the machined surface is very high, the standard tool cannot meet the machining requirements. Therefore, in the process of machining, the target design of tool material, blade shape, geometric angle, etc. can be divided into special orders and non special orders.
1、 Non custom tools mainly solve two problems, dimension and surface roughness
（1） Size problem
You can choose a standard tool with a size similar to that you need, which can be solved by regrinding. However, two points should be noted:
1. If the size difference is too large, the groove shape of the tool will change, which directly affects the chip removal space and geometric angle, so the size difference is not less than 2mm.
2. If it is a cutting machine without a knife hole, it can not be done with ordinary machine tools. It needs to be done with a special 5-axis connecting rod. The cost of changing machine grinding is also high.
（2） Surface roughness
This can be achieved by changing the geometric angle of the blade. For example, increasing the front and rear angles can significantly improve the surface roughness of the workpiece. However, if the rigidity of the user's machine tool is not enough, the cutting edge will become blunt and the surface roughness can be improved. This is very complex and requires an analysis of the treatment plant before any conclusions can be drawn.
2、 The tools to be customized mainly solve three problems: special shape, special strength and hardness, special tool tip tolerance and tool tip removal requirements
（1） The workpiece has special shape requirements
For example, the tool required for machining may be lengthened, the end teeth may be inverted, or there may be special taper angle requirements, tool shank structure requirements, blade length size control, etc. If the geometric requirements of this tool are not very complicated, it is actually easy to solve. The only thing to note is that non-standard tools are more difficult to handle. The pursuit of high precision means high cost and high risk, which will cause unnecessary waste to manufacturers' production capacity and their own costs.
（2） Strength and hardness of workpiece
When the workpiece is overheated, the common tool material is too strong and hard, or the tool is seriously worn. It needs to be transferred and has special requirements for the materials of tools. Common solutions are to choose high-grade tool materials, such as high-speed steel tools with high hardness cobalt for cutting hardened and tempered workpieces, and high-quality hard alloys. Machines replace grinding. Of course, it can also be very special. For example, when processing aluminum parts, it may not match the type of commercially available carbide tools. Aluminum parts are generally soft, but can be said to be easy to process. The material used for hard tools is actually an aluminum high-speed steel. Although this material is harder than ordinary high-speed steel, it will cause affinity of aluminum element and increase tool wear when processing aluminum parts. At this time, if you want to obtain high efficiency, you can choose cobalt high-speed steel instead.
（3） The workpiece has special requirements for blade tolerance and blade disassembly
In this case, a smaller number of teeth and deeper tooth tip grooves must be used, but this design can be used for mechanically simple materials such as aluminum alloys.
In the design and processing of non-standard tools, the geometric shape of the tool is relatively complex, and bending deformation, deformation and local stress concentration are easy to occur in the heat treatment process, which must be avoided in the design. For parts with concentrated stress, add bevel transition or step design for parts with large diameter change.
If it is a slender piece with large length and diameter, it needs to be checked and straightened after each fire-fighting and tempering to control the deformation and loss during heat treatment. The material of the tool is relatively brittle, especially the hard alloy material. If the vibration or machining torque is large during machining, the tool will be damaged. If the tool is broken, it can be replaced, but in many cases it will not cause too much damage. However, when handling non-standard tools, the possibility of replacement is high, so once the tool is broken, it will cause great losses. Users, including a series of problems such as delay.
