The definition of the tool The tool is a tool used for machining in machining, also known as a cutting tool. Generalized cutting tools include both tools and abrasive tools. The vast majority of cutting tools are machine-based, but they are hand-friendly. Because the tools used in mechanical fabrication are basically used for cutting metal materials, the term "tool" is generally understood as a metal cutting tool.

The development of cutting tools The history of cutting tools has played an important role in the history of human progress. As early as the Chinese BC, brass cones and copper cones, drills, knives, and other copper knives have appeared. In the late Warring States period (3rd century BC), copper knives were made due to the mastery of carburizing technology. The drills and saws at the time were similar to modern flat drills and saws.

However, the rapid development of cutting tools came in the late 18th century with the development of machines such as steam engines. In 1783, René of France first produced a milling cutter. In 1792, Modsley of the United Kingdom made taps and dies. The earliest documented invention of the twist drill was in 1822, but it was not produced as a commodity until 1864. The tool at that time was made of high-carbon tool steel and the allowable cutting speed was about 5 m/min. In 1868, Muchert made a tool alloy steel containing tungsten. In 1898, American Taylor and White invented high-speed steel. In 1923 Schreiter of Germany invented cemented carbide.

When alloy tool steels are used, the cutting speed of cutting tools is increased to about 8 m/min. When high-speed steels are used, they are increased by more than two times. When using hard alloys, they are more than double that of high-speed steels. The workpiece surface quality and dimensional accuracy are also greatly improved. Due to the high price of high-speed steel and hard alloys, the tool has a welded and mechanically clamped structure. From 1949 to 1950, the United States began to use indexable inserts on lathes and soon to be applied to milling cutters and other tools. In 1938, Germany's Degussa obtained patents on ceramic tools. In 1972, General Electric of the United States produced polycrystalline synthetic diamond and polycrystalline cubic boron nitride inserts. These non-metallic tool materials allow the tool to cut at higher speeds.

In 1969, Sandvik Steel in Sweden produced tungsten carbide coated carbide inserts by chemical vapor deposition. In 1972, Bonsa and Laguran in the United States developed physical vapor deposition methods, in carbide or high speed steel cutting tools. The surface is coated with a hard layer of titanium carbide or titanium nitride. The surface coating method combines the high strength and toughness of the base material with the high hardness and wear resistance of the surface layer, so that the composite material has better cutting performance.

Types of Tools The tools can be divided into five types according to the form of the workpiece: the tools for machining a variety of external surfaces, including turning tools, planing tools, milling cutters, broaches, boring tools, etc.; hole machining tools, including drill bits, reamers , boring reamers, reamers, broaches, etc.; thread cutting tools, including taps, dies, automatic opening and closing threads, thread turning tools, thread milling cutters, etc.; gear cutting tools, including hobs, shaper cutters, Shaving gears, bevel gear cutting tools, etc.; cutting tools, including circular saws, band saws, hack saws, cutting tools, saw cutters, etc. In addition, there are combination cutters.

According to the cutting movement mode and the corresponding cutting edge shape, the cutting tools can be divided into three categories: general-purpose cutting tools, such as turning tools, planing tools, milling cutters (not including shaped turning tools, forming planers, and forming cutters), boring tools, drill bits, Reaming reamers, reamers, saws, etc.; forming tools. The cutting edge of such tools has the same or nearly the same shape as the section of the workpiece being machined, such as a shaping tool, a forming planer, a profile cutter, a broach, a conical reamer, and All kinds of thread processing tools, etc.; development tool is the use of generative method to process the gear tooth surface or similar workpieces, such as hob, pinion cutter, shaving cutter, bevel gear planer and bevel gear cutter plate.

Structure of the tool The structure of various tools consists of the clamping section and the working section. The clamping part and the working part of the monolithic tool are made on the tool body; the working part (blade or blade) of the insert tool is mounted on the tool body. The clamping part of the tool has holes and handles. The holed cutter relies on the inner hole to be set on the spindle or mandrel of the machine tool, and the torsional moment is transmitted by means of an axial key or an end face key, such as a cylindrical milling cutter, a set face milling cutter and the like. The shanked tool usually has three kinds of rectangular shank, cylindrical shank and tapered shank. Turning tools, planers, etc. are generally rectangular shanks; taper shank taper axial thrust, and the use of friction to transmit torque; cylindrical shank is generally suitable for smaller twist drills, end mills and other tools, cutting with the clamping produced The friction force transmits the torsional moment. The shank of many shanked tools is made of low-alloy steel, while the working part is made of high-speed steel butt-welded.

The working part of the cutter is the part that generates and handles the chip, including the cutting edge, the structure that breaks or rolls the chip, the space for chip removal or storage, the channel of the cutting fluid, and other structural elements. The working parts of some tools are cutting parts, such as turning tools, planers, boring tools, and milling cutters; the working parts of some tools include cutting parts and calibration parts, such as drills, reamers, reamers, and inner surfaces. Knives and taps. The role of the cutting part is to remove the chip with the cutting edge, and the role of the calibration part is to trim the machined surface and guide the tool. The structure of the working part of the tool has three types: integral type, welding type, and mechanical clamping type. The overall structure is to make the cutting edge on the blade body; the welding structure is to braze the blade to the steel blade body; there are two kinds of mechanical clamping structure, one is to clamp the blade on the blade body, and the other is The brazed cutter head is clamped on the cutter body. Carbide tools are generally made of welded structures or mechanical clamping structures; porcelain tools are used mechanical clamping structure. The geometric parameters of the cutting part of the tool have a great influence on the level of cutting efficiency and the quality of the processing. Increasing the rake angle can reduce the plastic deformation when the rake face presses the cutting layer, reduces the frictional resistance of the chip flowing through the front, and reduces the cutting force and cutting heat. However, increasing the rake angle will also reduce the strength of the cutting edge and reduce the heat dissipation volume of the cutter head.

The choice of tool angle When selecting the tool angle, it is necessary to consider the influence of various factors, such as the workpiece material, tool material, processing properties (coarse, fine machining), etc., and must be reasonably selected according to the specific circumstances. Generally speaking, the tool angle refers to the manufacturing and measurement marking angles. In actual operation, due to the different installation positions of the tools and the change of the cutting movement direction, the actual working angle and the marked angle are different, but usually the difference is very different. small.

The direction of the development of the tool due to the high temperature, high pressure, high speed, and parts working in corrosive fluid medium, the application of more difficult to process materials, cutting automation and higher processing accuracy requirements . In order to adapt to this situation, the development direction of the tool will be to develop and apply new tool materials; to further develop the tool's vapor deposition coating technology, to deposit a higher hardness coating on a high-toughness and high-strength substrate to better solve The contradiction between the hardness and strength of the tool material; the development of the structure of the indexable tool; the improvement of the tool's manufacturing precision, the reduction of the difference in product quality, and the optimization of the use of the tool.

Tool Material The tool material is the fundamental factor that determines the cutting performance of the tool, and has a great influence on the machining efficiency, machining quality, machining cost, and tool life.