China's machinery industry history and development China's metal cutting has a long history. Ancient processing of stone, wood, bone and other non-metallic objects is the prelude to today's metal processing. In the Paleolithic stone slashing device, to the Neolithic Age, people fight with nature in the production tools have been continuously improved, such as: stone ax, stone knife, stone sickle and so on. And to be able to drill in the stone. Even the hard stone inlaid or bonded to the bone made of clamp-type stone blade. Since then, human beings have gradually realized the role of edge in production practice. It can be said that an original cutting process was formed. Basically have the basic conditions of cutting: cutting tools (with edge stone), be processed (production and daily necessities), cutting movement. China's metal cutting process, starting from the Bronze Age germination, and gradually formed and development. From the Yin Shang to the Spring and Autumn Period, there have been quite developed bronze smelting industry there have been a variety of bronze tools, such as: bronze knife, bronze file, bronze saws and so on. At the same time there are unearthed relics and Oracle records show that the production of bronze tools and living tools during this period, most of the manufacturing process to go through cutting or grinding. Metallurgical technology in our country more than a thousand years earlier than in Western Europe. The invention of carburizing, quenching, and steelmaking techniques has provided convenient conditions for making hard, sharp tools. The emergence of iron tools, indicating that the metal cutting process has entered a new phase. There are records that Shang Shang dating back 3,000 years ago already had a rotating jade tool, which is the predecessor of metal cutting machine tools. In the 1970s, five baht unearthed in Han Manchu, No.1 Hancheng, Hebei Province, had traces of turning on its outer circle, uniform flower knives, clear ripples of cutting vibrations and small ovality. It is possible to put five baht money on the square shaft and then clip it on a wooden lathe and carry the tool for cutting. In the 8th century, China had a metal-cutting lathe. By the Ming Dynasty, the handicraft industry had a great development, various cutting methods, with a more detailed division of labor. Such as: cars, milling, drilling, grinding and so on. From the astronomical instruments on the Beijing Astronomical Observatory, we can see that similar processing methods used in the 1950s and 1960s were adopted. This also shows that there was a higher precision grinding, turning, milling, drilling and so on. Its power is animal power and water power. In the late Qing Dynasty, the development of science and technology in our country was stagnating because of government corruption and foreign aggression, and the metal processing industry was still in a backward state. Before liberation, China's industry has been very backward, there is no own machine tool, tool manufacturing. Even such high-speed steel tool materials, general tools such as twist drill can not be manufactured. After liberation, China's machine tool has also made great strides. Machine tools and tool manufacturing from scratch, from small to large. In the seventies and eighties, further development of tooling materials, cemented carbide and high-speed steel specifications and varieties continue to increase. Such as: coated cemented carbide, cubic boron carbide, ceramics and so on. To the eighties CNC, digital display equipment has begun to develop. Due to the time of electronic equipment, computers, transmission and other effects, there is not much room for development. With the rapid development of electronic equipment, microcomputer, and transmission rate, numerical control and digital display devices have also developed rapidly. Today, China's machine tool manufacturing has basically been mature, especially in ordinary machine tools. Accurately speaking, machine tool is the carrier of advanced manufacturing technology, mechanical product quality, update speed, adaptability, efficiency depends to a great extent on the machine tool. China's current demand for machine tools will be mid-range CNC machine tools, machining centers and special machine-based. The other machine is relatively much less. And China's cutting-edge CNC machine tools and automated production line manufacturing can not be compared with the world's best player. However, our country also needs sophisticated, complex and intelligent equipment in military affairs and aviation. This also requires us to make every effort to catch up with them. Under such circumstances, we have also determined the development direction of China's CNC machine tools and improved the development of composite, high-speed, intelligent, sophisticated and environmental protection systems and improved the open CNC system of our country's independent intellectual property Platform and technical specifications, the development of intelligent CNC machine tools and network technology; further research parallel processing technology and set cars, grinding, milling, drilling, hinges, boring and other processes in one of the integrated technology to reduce the processing of clamping times; Overcome the manufacturing technology of functional components such as high-level spindle, linear motor and high-speed ball screw to improve product performance and technical level; popularize non-cooling, non-lubricating and odorless technologies in machining to reduce the pollution of the environment in the use of machine tools . Ordinary machine tools can not be less, in the small-scale manufacturer of ordinary machine tools is essential, these manufacturers mainly to repair and small batch production-based, some precision of civilian products is not very high, ordinary machine can fully meet their needs. Tool material development and status In modern machining, the tool material to hard alloy and high-speed steel used up, almost half of each. The invention and application of high-speed steel, has a full history of one century, cemented carbide has been half a century. However, both have developed many new varieties, their performance continues to increase, plays an important role in machining. In recent years, with the rapid development of CNC machining technology and the universal use of CNC machine tools, to achieve high efficiency, high stability, long-life processing. The application of super-hard tool is also increasingly popular, while introducing many advanced cutting concepts, such as high-speed cutting, hard machining, high stability machining, grinding on behalf of the vehicle, dry cutting and so on. Superhard cutting tool has become an indispensable tool in modern machining. (A) super-hard tool Super-hard tools include diamond cutting tools and cubic boron nitride cutting tools, including artificial diamond composite chip (PCD) cutter and cubic boron nitride composite (PCBN) cutter dominates. (1) PCD metal cutting tool PCD metal cutting tool can use PCD material of high hardness, high wear resistance, high thermal conductivity and low friction coefficient of non-ferrous metals and wear-resistant non-metallic materials with high precision, high efficiency, high stability And high surface finish processing. Such tools from the structure can be divided into mainly welded PCD tool and indexable PCD blade. In recent years, the rapid development of welded PCD tools is a standard PCD tool shank, such as PCD boring knife with handle, PCD boring knife, PCD reamer, knife handle type mainly cylindrical handle, taper shank and HSK handle . This type of tool, especially a multi-tooth cutter, features a small runout of the cutting edge on the shank (eg, an edge runout of 0.002 mm for an HSK shank PCD cutter with a 30 mm edge length) and is particularly suitable for use with various colored Forming parts of metal parts, holes, step holes and other high-volume high-speed processing. For example, a PCD high-speed milling cutter (six-edged, 100 mm diameter) with an aluminum matrix cutter provides maximum speeds up to 20,000 r / min and cutting speeds up to 7,000 m / min. The indexable PCD insert is a carbide cutting insert inserts a piece of PCD blanks after sharpening, can be clamped in a variety of CNC machine tools, tool holders or cutterhead for High-reliability high-volume processing. With the increasing popularity of CNC machine tools, machining centers and automatic production lines, the use of indexable PCD inserts is increasing, and its tool durability can be increased by several tens of times compared with that of carbide tools. (2) PCBN metal cutting tools PCBN metal cutting tools can also be divided into two types of PCBN cutting tools and PCBN blade can be indexable. Welding PCBN tool is welded PCBN blanks on the steel substrate by grinding, mainly turning tools, boring knives, reamers and so on. PCBN cutting tools are mostly used for machining ferrous metals, so the tip angle can not be too small, the tool front angle is generally -5 ° ~ 5 °, and the relief angle is generally 3 ° ~ 10 °. When cutting intermittently, negative Chamfer. The PCBN inserts (mainly car blades and milling inserts) are generally insert-edged PCBN blanks at one corner of the indexable cemented carbide insert and sharpened. Taking into account the more expensive blanks and resurfacing and other reasons, generally only made a knife tip. With the improvement of welding quality, its shear strength up to 0.78kg / m2. As PCBN blanks become smaller and smaller, the price of non-reworked PCBN blades is reduced. (B) the typical application of super-hard tool (1) hard-processing, to the car instead of grinding PCBN tool with high hardness and red hardness, can be processed high hardness parts get a good surface roughness, so the use of PCBN Tool turning hardened steel can be achieved "to the car on behalf of the mill." Examples of applications such as automotive, motorcycle gear hole processing, such parts materials are generally 20CrMnTi, carburizing and quenching, the surface hardness of 60 ~ 62HRC, gear hole accuracy of IT6, the surface roughness Ra ≤ 0.8μm. The traditional processing technology: Machining -> heat treatment -> grinding. The use of super-hard tool "to the car on behalf of the mill" processing technology: roughing -> heat treatment -> finishing. The new process can greatly improve the processing efficiency and reduce processing costs, the original use of a class of grinding process can only process 100 pinions, is the use of PCBN turning tool (cutting parameters V = 60 ~ 120m / min, f ≤ 0.12mm / r , Ap≤0.1mm, a group can process 400 pinions, in addition, the processing costs allocated to each gear also declined. (2) high-speed cutting, high stability processing In the automotive engine production line, gray cast iron cylinder Cylinder hole finishing is one of the key processes, requiring high precision cylinder bore size, surface roughness is small, good stability; due to fast processing line beat, requiring high cutting speed (usually V ≥ 500m / min), long tool life (Processing holes ≥ 1000), and chamfering, only mouth, rough fine boring and other positions of the blade life should meet the durability requirements. The use of PCBN tools to achieve high-speed machining of the cylinder bore and high stability of the processing , The typical cutting parameters are: V = 500m / min, f = 0.2 ~ 0.4mm / r, ap = 0.2 ~ 0.7mm; the surface roughness Ra≤1.6μm, tool life> High speed, high stability, low roughness plus And mirror processing PCD tool for non-ferrous metals processing, due to the high hardness of diamond, metal and metal surface affinity is small, and the tool is generally polished into a mirror, easy to produce BUE, so the processing of dimensional stability and surface quality are good, tool life For example, the use of PCD tool commutator commutator copper commutator, the typical cutting parameters: V = 300m / min, f = 0.08mm / r, ap≤0.15mm, the processing surface roughness Ra0.1 ~ 0.2μm, tool life> 5,000 pieces, while the use of carbide cutting tools can only be processed a few pieces. PCD tool for processing all kinds of silicon aluminum alloy parts, surface roughness Ra ≤ 0.1μm, tool life up to several thousand ~ tens of thousands Piece, especially suitable for mass production of automobile and motorcycle parts.Using single-crystal diamond tool, it can realize the mirror spherical processing on the ultra-precision lathe.The machine adopts the ultra-precision gas static pressure spindle and rotary table, the runout is less than or equal to 0.3μm, Workpiece using high-precision pneumatic chuck, enabling fast and high-precision positioning. Oxygen-free copper processing materials, the surface roughness Ra ≤ 0.025μm, roundness ≤ 0.3μm; processing aluminum , Surface roughness Ra≤0.025μm. (4) Dry cutting, cleaning and processing PCBN tool machining boron-containing cast iron cylinder liner, cutting parameters: V = 200m / min, f = 0.1mm / r, ap = 0.2 ~ 1mm , Machined surface roughness Ra≤1.6μm, precision IT6, tool life between two sharpening tools> 100 pieces, which can realize "grinding on behalf of the car." Due to the use of dry cutting, cutting (grinding) cutting fluid and grinding wheel gray The pollution of the environment, the chip can be recycled and reused, in line with the requirements of cleaner production. The above-mentioned tool prices more expensive Some small manufacturers because of the cost of the problem will not go to a large number of purchases. (C) China's new tool This rare earth elements added carbide cutting tool is one of the new varieties. Rare earth elements refer to the atomic number 57-71 (from La to Lu) in the Periodic Table of the Chemical Element, plus 21 and 39 (Sc and Y) for a total of 17 elements. Some of the rare earth elements, in a certain way, trace added to the traditional carbide grades, you can effectively improve their mechanical properties and cutting performance. Rare earth resources in China are rich in resources, research and development of rare earth cemented carbide, ahead of other countries. RG8R (equivalent to ISOK30 grade), YG6R (K20), YW1R (M10), YW2R (M20), YT5R, YT14R (P20), YT15R (P10) and YS25R (P10) have been developed. P25). There are mines, geological tools grade YG11CR. In YG8, YT14, YW1 cemented carbide added Ce, Y and other rare earth elements, the formation of rare earth cemented carbide YG8R, YT14R, YW1R. YG8R is mainly used for roughing cast iron and non-ferrous metals; YT14R is mainly semi-finished steel; YW1R is a universal grade, which can be used for semi-finishing of various workpiece materials. After testing, the microstructure of cemented carbide after adding rare earth elements is relatively dense; the hardness at room temperature and the hardness at high temperature are improved; the fracture toughness and flexural strength are significantly increased by 20% and 10% respectively. Rare Earth Carbide Wear and Service Life Test Some tests show that the wear resistance and service life of YG8R, YT14R and YW1R blades are all improved to some extent compared with those of rare earth-free original blades. Rare earth carbide compared with the original blade without rare earth elements, the turning spline shaft steel, then the tip impact, until the tip damage. After repeated tests, before the tip damage, YG8R, YT14R, YW1R blade can withstand the number of times than the YG8, YT14, YW1 blade increased by 1 to 2 times more advantages. Rare earth elements exist in (W, Ti) C or (W, Ti, Ta, Nb) C solid solution, can strengthen the hard phase, and can inhibit the WC grains grow unevenly, making it uniform, the average grain size Decreased. A small amount of rare earth elements also solid solution in the binder phase Co, the binder phase is strengthened. Rare earth elements are enriched in the phase interface of WC / Co and (W, Ti) C / (W, Ti) C and other phase interface, often with the impurities S, O and other compounds formed RE2O2S and other compounds to improve the cleanliness of the interface And improve the wetting phase of the hard phase and the binder phase. As a result, the impact toughness, flexural strength and impact resistance of the rare earth cemented carbide significantly improved. Its hardness, wear resistance and resistance to diffusion and anti-oxidation on the surface of the tool also increased to a certain extent. After the electron microscopy test, it is also found that the rare earth cemented carbide inserts have cobalt-rich surface during cutting, which can reduce the friction coefficient between the chips and the workpiece and the cutting tool so as to reduce the cutting force. Rare earth elements are rich in nature, the price is not high, added to the cemented carbide can significantly improve mechanical, physical properties and performance, it has broad application prospects.
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Gound Type Dumbwaiter
Gound Type Dumbwaiter, dumbwaiter, service lift
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