Reasons and solutions for fast wear of OEM machining tools
The development of modern manufacturing technology and the widespread use of CNC machining equipment have greatly promoted the progress of cutting technology. With the need for CNC and automation of OEM machining process, the emergence of super heat-resistant alloy, titanium alloy and carbon fiber-containing composite materials, etc., has imposed more stringent requirements on the quality of metal cutting tools, high reliability, high precision, long life, Quick index replacement, good chip breaking, etc., the hot hardness of the tool and the problem of tool wear have become the key to the cutting process.
1. Common tool wear patterns
In cutting, the tool wear that usually occurs includes the following three forms:
The first type is wear due to mechanical action, such as chipping or abrasive wear;
The second type of wear due to cutting heat, such as adhesion, diffusion, etc.;
The third type is the breakage, thermal fatigue, and thermal cracking caused by the softening and melting of the cutting edge caused by chemical factors.
(1) Causes of mechanical wear
When cutting difficult-to-machine materials, tool wear occurs within a short period of time. This is due to the fact that there are many factors in the processed material that promote tool wear. Most difficult-to-machine materials have the characteristics of low thermal conductivity. As a result of this effect, the bonding strength of the binder in the tool material will decrease at high temperatures, thereby accelerating tool wear.
(2) Wear due to cutting heat
When cutting materials with high hardness and high toughness, the cutting edge temperature is very high, and tool wear similar to that when cutting difficult-to-machine materials will occur. Especially when machining workpiece materials that generate short chips, crescent crater wear will occur near the cutting edge, and tool breakage often occurs in a short time.
(3) Wear caused by chemical factors
Components in difficult-to-machine materials and some components in tool materials react under high-temperature conditions of cutting, appearing out, falling off, or generating other compounds, which will accelerate the formation of tool wear phenomena such as chipping.
2. Performance requirements of cutting tools
(1) Wear resistance
The materials of metal cutting tools currently used are different, ranging from high-speed steel with the lowest cutting speed and worst wear resistance to polycrystalline diamond tools with the best high-speed performance.
(2) Impact resistance
has relatively good impact toughness, in addition, high-speed cutting tools must also have extremely high thermal hardness and chemical stability.
(3) Service life
uses a coating material with good heat resistance and high hardness and a multi-layer coating technology to make the cutting range of coated carbide tools large and long life.
3. Commonly used tool materials
(1) Alloy tool steel
has high thermal rigidity but low price. It is commonly used to manufacture low-speed tools with complicated shapes, such as reamer, tap and die.
(2) High-speed tool steel
Its high temperature hardness and wear resistance are better than alloy tool steel. Because of its good heat treatment performance, high strength and good sharpness, it is widely used in the manufacture of various machine tools such as forming turning tools, milling tools, drill bits and broaches.
is an alloy made of materials such as tungsten carbide, titanium carbide and cobalt by powder metallurgy. It is usually used to fix the cemented carbide blade on the cutter body. At present, cemented carbide has become one of the main tool materials.
In order to prevent the tool from wearing too fast, special cutting fluid should be selected, which has the following advantages:
(1) Improve the process accuracy. The special cutting fluid containing the sulfide extreme pressure anti-wear additive component can effectively protect the tool and improve the process accuracy.
(2) The special cutting fluid that meets the process requirements has passed strict tests in terms of viscosity, flash point, pour point, and thermal conductivity to meet the needs of various cutting processes.
(3) Compared with rapeseed oil, mechanical oil and regenerated oil, the special cutting fluid with good environmental protection performance has good stability and will not cause harm to equipment, human body and environment.