Views:3 Author:Site Editor Publish Time: 2020-07-02 Origin:Site
With the development of modern science and technology, CNC machining equipment has been developed continuously, and at the same time, it has greatly promoted the progress of cutting technology. With the continuous improvement of production technology requirements, as well as the continuous approaching of automation trend, the material of cutting tools began to change, and the cutting tools made of new materials such as titanium alloy, carbon fiber composite material, super heat-resistant alloy, etc. were constantly emerging, which made the quality of cutting tools continue to improve, and the key factors such as the reliability, accuracy, life of cutting tools have also been greatly developed and improved.
1. Tool wear pattern
In machining, the tool will lose after using for a period of time, and the specific manifestations of wear are as follows:
a. Loss due to mechanical action, such as abrasive wear or chipping;
b. Adhesion and diffusion caused by high heat generated during cutting;
c. The softening and melting of cutting edge caused by the infection of chemical materials.
Next, we analyze the causes of the three loss forms one by one:
(1) Causes of wear under mechanical action
When machining difficult to machine materials, tool wear is very easy to occur. This is because most of the difficult to machine materials have the characteristics of low heat conductivity, which will affect the adhesive strength of the tool materials in the high temperature state, thus accelerating the tool wear.
(2) Wear caused by too high tool temperature
When cutting materials with high toughness and hardness, the cutting edge temperature of the tool is generally high, which will lead to tool wear. Especially when cutting short scraps, there will be crescent wear near the cutting edge, which makes the tool wear in a very short time.
(3) Abrasion caused by chemical raw materials
For the cutter, some special components in its component materials will have wonderful chemical reactions with the components of processing materials in specific situations, which makes the coating of cutter fall off or even become other chemicals. The occurrence of this phenomenon will accelerate the occurrence of knife edge collapse, wear and other situations.
2. Tool performance requirements
(1) Wear resistance
At present, there are many kinds of cutting tools, and the materials of cutting tools are also very different, from the worst white steel cutter to the best diamond cutter. The performance difference between them is more than one.
(2) Impact resistance
A good tool needs to have good impact toughness. For cutting tools in high-speed environment, they also need to have excellent thermal hardness and chemical stability.
(3) Service life
Today's cutting tools, a little better will be coated with a layer of heat-resistant, high hardness layer material or even multi-layer coating, just to increase the cutting range and tool life.
3. Tool material
(1) Alloy tool steel
For alloy tool steel, it is a common feature that it has high heat hardness. At the same time, the price is common. It is often used to make reamers, taps and other low-speed tools with complex shapes.
(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 grinding performance. It is often used to make forming turning tools, milling tools, drills and other common machine tools.
(3) Cemented carbide
This is an alloy made of carbide, titanium carbide, cobalt and other materials by powder metallurgy. At present, cemented carbide has become one of the most mainstream tool materials.