Common Knowledge and Usage of Metal Cutting Tools

Common Knowledge and Usage of Metal Cutting Tools

End Mill

When choosing the angle of the milling tool, it is necessary to consider the influence of many factors, such as workpiece material, tool material, processing properties (rough and fine processing), etc., and it must be reasonably selected according to the specific situation. The tool angle usually refers to the marked angle used for manufacturing and measurement. In actual work, due to the different installation positions of the tool and the change of the cutting movement direction. The actual working angle is different from the marked angle, but the difference is usually very small.

The material used to make the tool must have high high-temperature hardness and wear resistance, necessary bending strength, impact toughness and chemical inertness, good processability (cutting, forging and heat treatment, etc.), and is not easy to deform.

Usually when the material hardness 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. High-speed steel has high bending strength and impact toughness, as well as good machinability. Modern is still the most widely used tool material, followed by cemented carbide tools.

Polycrystalline cubic boron nitride is suitable for cutting high-hardness hardened steel and hard cast iron. Polycrystalline diamond is suitable for cutting non-ferrous metals, alloys, plastics and fiberglass. Carbon tool steel and alloy tool steel are now only used as tools such as files, dies and taps.

 End Mills

Cemented carbide indexable inserts are now coated with titanium carbide, titanium nitride, aluminum oxide hard layer or composite hard layer by chemical vapor deposition. The developing physical vapor deposition method can be used not only for cemented carbide tools, but also for high-speed steel tools such as drill bits, hobs, taps and milling cutters. The hard coating acts as a barrier to hinder chemical diffusion and heat conduction, slowing down the wear rate of the tool during cutting. The life of the coated blade is about 1 to 3 times higher than that of the uncoated one.

Due to the fact that parts working under high temperature, high pressure, high speed and in corrosive fluid media are using more and more difficult-to-process materials, the automation level of cutting processing and the requirements for processing accuracy are getting higher and higher. In order to adapt to this situation, the development direction of tools will be to develop and apply new tool materials. Further develop the vapor deposition coating technology of the tool, 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.

According to the cutting motion mode and the corresponding blade shape, the tool can be divided into three categories. General tools, such as turning tools, planing tools, milling cutters (excluding formed turning tools, forming planing tools and forming milling cutters), boring tools, drills, reamer drills, reamers and saws. Forming tools, the blades of this type of tools have the same or nearly the same shape as the cross-section of the workpiece being processed, such as forming turning tools, forming planing tools, forming milling cutters, broaches, conical reamers and various thread processing tools. Generating tools are used to process the tooth surface of gears or similar workpieces by the generating method, such as hobs, gear shaping cutters, gear shaving cutters, bevel gear planing cutters and bevel gear milling cutter discs.

The structure of various tools consists of a clamping part and a working part. The clamping part and working part of the integral structure tool are made on the tool body. The working part (teeth or blade) of the toothed structure tool is mounted on the tool body.

End Mills

The clamping part of the tool is divided into two types: with hole and with handle. The hole tool is mounted on the spindle or spindle of the machine tool by the inner hole, and the torsional torque is transmitted by the axial key or end face key, such as cylindrical end mill, sleeve face milling cutter, etc.

Tools with handles usually have three types: rectangular handle, cylindrical handle and tapered handle. Turning tools, planing tools, etc. generally have rectangular handles. Conical handle, the taper bears axial thrust and transmits torque by friction. Cylindrical handles are generally suitable for smaller twist drills, end mills and other tools. When cutting, the torsional torque is transmitted by the friction generated during clamping. The handle of many tools with handles is made of low-alloy steel, and the working part is made of high-speed steel by welding the two parts.

The working part of the tool is the part that produces and processes chips, including the blade, the structure that breaks or rolls up the chips, the space for chip removal or storage, the channel for cutting fluid and other structural elements.

The working part of some tools is the cutting part, such as turning tools, planing tools, boring tools and milling cutters. The working part of some tools includes the cutting part and the calibration part, such as drills, reamer drills, reamers, internal surface broaches and taps. The function of the cutting part is to remove chips with the blade, and the function of the calibration part is to polish the cut surface and guide the tool.

The structure of the working part of the tool is integrated, welded and mechanically clamped. The integrated structure is to make the cutting edge on the tool body. The welded structure is to braze the blade to the steel tool body. There are two types of mechanical clamping structures, one is to clamp the blade to the tool body, and the other is to clamp the brazed tool head to the tool body. Carbide tools are generally made of welded structures or mechanically clamped structures. Ceramic tools all use mechanical clamping structures.

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