What are the reasons for the rapid wear of cutting tools for machining?
The development of science and technology has continuously developed CNC machining equipment, and it has also greatly promoted the progress of cutting technology. With the continuous improvement of production technology requirements and the continuous approach of automation trends, the materials of cutting tools have begun to change, and cutting tools made of new materials such as titanium alloys, carbon fiber composite materials, super heat-resistant alloys, etc., continue to appear, so that the quality of cutting tools continues to improve. The key factors such as the reliability, accuracy and life of the tool have also been greatly developed and improved.
1. Tool wear patterns
In mechanical processing, the tool will wear out after using it for a period of time, and the specific performance of wear is mainly in the following three forms:
1. Losses that occur under mechanical action, such as abrasive wear or chipping;
2. Bonding and diffusion caused by high heat generated during cutting;
3. The cutting edge is softened and melted due to the infection of chemical raw materials.
Next, we analyze the reasons for these three types of loss one by one:
(1) Causes of wear under mechanical action
When cutting hard-to-machine materials, tool wear is very easy to occur, because most of the hard-to-machine materials have the characteristics of low thermal conductivity, which will affect the adhesive in the tool material at high temperatures In this state, the bonding strength decreases, thereby accelerating tool wear.
(2) Wear caused by excessive tool temperature
When cutting high-toughness and high-hardness materials, the cutting edge temperature of the tool is generally high, which will cause the tool to wear. Especially when cutting workpieces with short chip waste, crescent wear will occur near the cutting edge, making the tool wear out in a very short time.
(3) Wear caused by chemical raw materials
For the tool, some special components in the material will produce a wonderful chemical reaction with the composition of the processing material in a specific situation, causing the coating of the tool to fall off or even become other chemicals. The occurrence of chipping, abrasion, etc.
2. Performance requirements of cutting tools
(1) Wear resistance
There are various types of cutting tools at present, and the materials that make up the tools are also very different. They range from the worst white steel knives to the best diamond knives. The performance difference between them is even more heavenly and underground.
(2) Impact resistance
An excellent tool needs to have good impact toughness. For cutting tools in a high-speed environment, they also need to have excellent hot hardness and chemical stability.
(3) Service life
Nowadays, the slightly better ones will coat the tool with a layer of heat-resistant, high-hardness layer material or even multiple layers of coatings, just to increase the cutting range of the tool and increase the life of the tool.
3. Tool material
(1) Alloy tool steel
For alloy tool steel, it is common to have high hot hardness, and at the same time, the price is civilian, and it is often used to make low-speed tools with complex shapes such as reamer and tap.
(2) High-speed tool steel
High temperature, high hardness and high wear resistance are the advantages of high-speed tool steel. At the same time, due to its good heat treatment performance, it has high strength and good sharpness. It is often used to make forming turning tools, milling cutters, drills, etc. Machine tool.
This is an alloy made of carbide, titanium carbide, cobalt and other materials through powder metallurgy. At present, cemented carbide has become one of the most mainstream tool materials.