[Types and use of engraving knives] Material selection for manufacturing knives

When selecting the angle of the tool, you need to consider the influence of various factors, such as workpiece material, tool material, processing properties (rough, finishing), etc., must be selected reasonably according to the specific situation. Generally speaking, the tool angle refers to the marked angle used for manufacturing and measurement. In actual work, due to the different installation position of the tool and the change of the cutting movement direction, the actual working angle and the marked angle are different, but usually the difference is small .

The choice of materials for manufacturing tools must have high high-temperature hardness and wear resistance, the necessary bending strength, impact toughness and chemical inertness, good manufacturability (cutting, forging and heat treatment, etc.), and not easy to deform.

Generally, when the hardness of the material is high, the wear resistance is also high; when the bending strength is high, the impact toughness is also high. But the higher the hardness of the material, the lower its bending strength and impact toughness. Due to its high bending strength, impact toughness, and good machinability, high-speed steel is still the most widely used tool material, followed by cemented carbide.

Polycrystalline cubic boron nitride is suitable for cutting high-hardness hardened steel and hard cast iron; polycrystalline diamond is suitable for cutting metals that do not contain iron, as well as alloys, plastics and glass steel; carbon tool steel and alloy tool steel are now only used Used as tools such as files, die and taps.

Carbide indexable inserts have now been coated with titanium carbide, titanium nitride, aluminum oxide hard layers or composite hard layers by chemical vapor deposition. The physical vapor deposition method being developed can be used not only for cemented carbide tools, but also for high-speed steel tools, such as drills, hobs, taps and milling cutters. The hard coating acts as a barrier that hinders chemical diffusion and heat conduction, which slows down the wear rate of the tool during cutting. The life of the coated blade is about 1 to 3 times longer than that of the uncoated one.

Due to the high temperature, high pressure, high speed, and parts that work in corrosive fluid media, the application of more and more difficult-to-process materials, the automation level of cutting processing and the requirements for processing accuracy are becoming higher and higher. In order to adapt to this situation, the development direction of the tool will be to develop and apply new tool materials; further develop the tool's vapor deposition coating technology, deposit a higher hardness coating on a high toughness and high strength substrate, and better solve The contradiction between the hardness and strength of the tool material; further develop the structure of the indexable tool; improve the manufacturing accuracy of the tool, reduce the difference in product quality, and optimize the use of the tool.

Tool materials are roughly divided into the following categories: high-speed steel, cemented carbide, cermets, ceramics, polycrystalline cubic boron nitride, and polycrystalline diamond.