What cutting tools are required in CNC machining services? Generalized cutting tools include both cutting tools and grinding tools. Most of the cutting tools are used for machines, but there are also hand tools. Cutting tools used in mechanical manufacturing are basically used to cut metal materials. Common CNC cutting tools including turning tools, milling tools, drill bit, and more. Cutting tools for machining various external surfaces, including turning tools, planers, milling cutters, broaches, etc., hole processing tools, including drill, reamer, boring tool, milling tool and inner surface broach, etc; thread manufacturing tools, including tap, die, automatic thread cutting head, thread turning tool and thread milling tool, etc. These tools need to meet certain requirements.
Properties of Cutting Tools Used in CNC Machining and Manufacturing
Let’s check out the basic properties and performance CNC cutting tools needed.
The hardness of the tool material must be higher than that of the material of CNC parts to be processed. Otherwise, the sharp geometry of the tool can not be maintained under high temperature, which is the basic feature of the tool material. At present, the hardness of carbon tool steel, the tool material with the worst cutting performance, should be above 62HRC at room temperature; the hardness of high speed steel is 63-70HRC; the hardness of cemented carbide is 89-93HRA.
Good strength and toughness
The material of the cutting part of the tool has to bear great cutting force and impact force when cutting. For example, when CNC turning steel, when AP = 4 mm, f = 0.5 mm / R, the cutting force of the blade is about 4000 N. Therefore, the tool material must have enough strength and toughness. Generally, the bending strength (unit: PA) of tool material is used to express its strength, and the impact toughness (unit: J / m2) is used to express its toughness, which reflects the ability of tool material to resist brittle fracture and edge collapse.
High wear resistance and heat resistance
The wear resistance of tool material refers to the ability to resist wear. Generally speaking, the higher the hardness of tool material, the better the wear resistance. In addition, the wear resistance of the tool material is also related to the chemical composition in the metallographic structure, the nature, quantity, particle size and distribution of the hard spots. The more carbides in the microstructure, the finer the particles and the more uniform the distribution, the higher the wear resistance. The wear resistance and heat resistance of tool materials are closely related. Its heat resistance is usually measured by its high temperature hardness, or red hardness. The higher the hardness at high temperature, the better the heat resistance, and the stronger the resistance to plastic deformation and wear of the tool material at high temperature. Tool materials with poor heat resistance lose their cutting ability due to rapid wear and plastic deformation due to the significant decrease of hardness at high temperature.
Good thermal conductivity
The thermal conductivity of tool material is expressed by thermal conductivity [w / (m·K)]. High thermal conductivity means good thermal conductivity, and the heat capacity generated during cutting is easy to conduct out, so as to reduce the temperature of the cutting part and reduce tool wear. In addition, it is very important to use the tool material with good thermal conductivity for intermittent cutting, especially when machining the workpiece with poor thermal conductivity.
Good technology and economy
In order to facilitate manufacturing, the tool material is required to have good machinability, including forging, welding, cutting, heat treatment, grindability, etc. Economy is one of the important indexes to evaluate and popularize new tool materials. The selection of tool materials should be combined with domestic resources to reduce the cost.
It can prevent the adhesion between the workpiece and the tool material molecules under the action of high temperature and high pressure.
It means that the tool material is not easy to react with the surrounding medium at high temperature.