Cutting tools, refers to the machinery used in cutting processing tools, including drill bits, cutter, reamer, drill reamer, boring tool, hole processing tools.
The generalized cutting tool includes both the tool and the abrasive. The vast majority of the tool is machine, but there are hand with. Since the tool used in the manufacture of machinery is basically used for cutting metal materials, the term "tool" is generally understood as a metal cutting tool. Cutting tools for wood are called woodworking tools.
Cutting tools of the main products
Solid carbide tools: drill bits, boring tools, hole processing tools, and for the user to design a variety of difficult tool. Products for alloy steel, stainless steel, quenched and tempered steel, non-ferrous metal and so on. For the production of automobiles, motorcycles engines, diesel engines, carburetors, refrigerator compressors, mold industry and other manufacturers to provide a variety of forming tools. The main products supporting the processing center, CNC machine tools and other high-precision machine tools.
The development of cutting tools
The development of the tool occupies an important position in the history of human progress. China as early as 28 BC before the 20th century, there have been brass cone and copper cone, drill, knife and other copper cutting tools. The late Warring States period (the third century BC), due to master the carburizing technology, made of copper cutter. At that time the drill and saw, and the modern flat drill and saw some similarities.
However, the rapid development of the tool is in the late 18th century, with the development of steam machines and other machines. In 1783, the French Rene first made a cutter. In 1792, the United Kingdom's Mozi made taps and die. The earliest literature on the invention of twist drill was in 1822, but it was not until 1864 as a commodity.
At that time the tool was made of the whole high-carbon tool steel, the allowable cutting speed of about 5 m / min. In 1868, the British mousse made tungsten alloy tool steel. In 1898, the United States of Taylor and. White invented high speed steel. 1923, Germany's Schleswig. Teer invented the cemented carbide.
In the use of alloy tool steel, the cutting speed of the tool increased to about 8 m / min, the use of high-speed steel, and more than doubled to the use of cemented carbide, compared with high-speed steel more than doubled, The workpiece surface quality and dimensional accuracy is also greatly improved.
As high-speed steel and carbide prices are more expensive, the tool appears welding and mechanical clamping structure. Between 1949 and 1950, the United States began to use indexable inserts on the turning tools, and soon applied to milling cutters and other tools. In 1938, the German Deusa company made a patent on the ceramic tool. In 1972, the United States General Electric Company produced polycrystalline synthetic diamond and polycrystalline cubic boron nitride blade. These non-metallic tool materials allow the tool to be cut at a higher speed.
In 1969, the Swedish Sandvik steel mill made a patented chemical vapor deposition method to produce titanium carbide coated carbide inserts. In 1972, the United States Bangsha and Laguna developed a physical vapor deposition method, in the carbide or high-speed steel tool surface coated with titanium carbide or titanium nitride hard layer. The surface coating method combines the high strength and toughness of the matrix material with the high hardness and abrasion resistance of the surface layer, resulting in better cutting performance of the composite material.
The main classification of cutting tools
The tool can be divided into five categories according to the surface of the workpiece. Processing of various kinds of outer surface of the tool, including turning tools, planer, milling cutter, the outer surface of the broach and rasp; hole processing tools, including drill, reaming drill, boring knife, reamer and inner surface broach; Tools, including taps, die, automatic opening and closing thread cutting, thread turning tools and thread cutter, etc .; gear processing tools, including hob, shaper cutter, shaving cutter, bevel gear cutting tool, cutting tool, Tooth saw blades, Band saws, Bow saws, Cutters and saw blades, etc. In addition, there are combinations of tools.
According to the cutting movement and the corresponding blade shape, the tool can be divided into three categories. General tools such as turning tools, planers, milling cutters (excluding forming turning tools, forming planers and forming cutters), boring tools, drills, reamers, reamers and saws; forming knives, With the same or near the same shape of the workpiece, such as forming a knife, forming planer, forming cutter, broach, cone reamer and a variety of thread processing tools; Toothed or similar workpieces such as hobs, shaper shaper, shaving cutter, bevel gear planer and bevel gear cutter.
The composition of the cutting tool
The structure of the various tools are composed of clamping part and working part. The working part of the tool and the working part of the tool are made on the cutter body. The working part of the tool is set on the cutter body.
The clamping part of the tool has two kinds of hole and handle. The tool is set on the spindle or mandrel of the machine with the inner hole of the machine, and the torsional moment is transmitted by means of the axial key or the face key, such as cylindrical cutter, nested milling cutter and so on.
The morphological structure of the cutting tool
The tool with the handle is usually rectangular handle, cylindrical handle and cone handle three. Tools, etc., for the rectangular handle; cone shank * taper to withstand axial thrust, and with friction to transmit torque; cylindrical handle is generally applicable to smaller twist drill, end mills and other tools, cutting with the help of clamping The resulting frictional force imparts torsional moments. A lot of handle with the handle of the handle with low alloy steel, and the working part of the high-speed steel with two parts welded together.
The working part of the tool is to produce and deal with the chip part, including the blade, so that the chip broken or winding structure, chip removal or storage chip space, cutting fluid channel and other structural elements. Some of the working parts of the tool are cutting parts, such as turning tools, planers, boring tools and milling cutters, etc .; some of the working part of the tool contains cutting parts and calibration parts, such as drill, reaming drill, reamer, Knives and taps and so on. The role of the cutting part is to cut the chip with the blade, the role of the calibration part is to repair the machined surface and guide the cutting tool.
The working part of the tool has three kinds of integral, welded and mechanical clamping. The overall structure is made in the cutter body cutting edge; welding structure is the blade brazing to the steel body; mechanical clamping structure and two, one is the blade clamp on the knife body, the other Is a good brazing head on the cutter body. Carbide tool is generally made of welded structure or mechanical clamping structure; porcelain tool are used mechanical clamping structure.
The geometric parameters of the cutting part of the tool have a great influence on the cutting efficiency and the quality of the machining. Increasing the rake angle reduces the plastic deformation of the rake face when the cutting layer is squeezed, reducing the frictional resistance of the chip through the front, thereby reducing the cutting force and cutting heat. But increase the rake angle, while reducing the strength of the cutting edge, reducing the heat dissipation of the blade.
Selection of cutting tools
In the choice of tool angle, the need to consider the impact of a variety of factors, such as workpiece materials, tool materials, processing properties (rough, finishing), etc., must be reasonably selected according to specific circumstances. Generally speaking, the angle of the tool is the angle of the manufacturing and measurement. In the actual work, the actual working angle and the angle of the mark are different because of the different installation position of the tool and the direction of the cutting movement, but usually the difference is very small The
The material of the tool must have high hardness and abrasion resistance, the necessary bending strength, impact toughness and chemical inertness, good process (cutting, forging and heat treatment, etc.) and is not easy to deform.
Usually when the material hardness is high, wear resistance is also high; bending strength is high, the impact toughness is also high. But the higher the hardness of the material, the lower the bending strength and impact toughness. High-speed steel because of its high bending strength and impact toughness, and good machinability, modern is still the most widely used tool material, followed by carbide.
Polycrystalline cubic boron nitride is suitable for cutting high hardness hardened steel and hard cast iron. Polycrystalline diamond is suitable for cutting iron-free metals, alloy, plastic and glass fiber reinforced plastic, etc .; carbon tool steel and alloy tool steel are now only For tools such as rasp, die and tap.
The Application and Significance of Cutting Tools
Carbide indexable inserts have now been coated with titanium carbide, titanium nitride, aluminum oxide or composite hard layers by chemical vapor deposition. The development of the physical vapor deposition method can be used not only for carbide cutting tools but also for high speed steel tools such as drill bits, hobs, tapes and milling cutters. Hard coating as a barrier to chemical diffusion and heat conduction barrier, so that the cutting tool in the cutting speed slowed down, the life of the coated blade and the coating compared to about 1 to 3 times higher.
Due to the high temperature, high pressure, high speed, and in corrosive fluid medium work parts, the application of more difficult to process materials, cutting the level of automation and processing accuracy requirements are getting higher and higher. In order to adapt to this situation, the direction of the development of the tool will be the development and application of new tool materials; further development of the tool vapor deposition coating technology, high toughness in the high strength of the matrix deposited higher hardness coating, better solution Tool material hardness and strength of the contradictions; further development of indexable tool structure; to improve the manufacturing accuracy of the tool to reduce the difference in product quality, and to optimize the use of the tool.
