Abrasive belt

Abrasive belts are coated abrasives and are called flexible abrasives. Compared with solid abrasive grinding wheels, it is more flexible and safer during polishing, has higher precision and has the advantages of low grinding cost. Abrasive belt grinding is a form of grinding with coated abrasive tools (commonly known as sandpaper and emery cloth). As early as 1760, the first sandpaper appeared in the world, but at that time it was only limited to manual operations. It was not until 1900 to 1910 that the era of mechanical use of sandpaper and emery cloth entered, and it was first used in the wood industry in the form of annular belts. This mechanical grinding method using annular belts of emery cloth was the prototype of abrasive belt grinding. After 1930, abrasive belt grinding gradually developed into metal processing. During World War II, the United States took the lead in using abrasive belt grinding in weapons manufacturing and achieved remarkable results. In the early 1950s, the emergence of the electrostatic sand planting method pushed abrasive belt grinding to a new stage, and the application of abrasive belt grinding became increasingly common. Later, Europe and Japan also successively carried out the research and application of abrasive belt grinding technology, and abrasive belt grinding technology gradually developed into an independent processing technology field with complete categories and a relatively complete technical system. The composition of the abrasive belt An abrasive belt is a belt-shaped tool that can be used for grinding and polishing. It is a belt-shaped tool that uses a binder to bond abrasives to flexible materials such as paper and cloth. It is a main form of coated abrasive tools. Its basic components are: base material, abrasive and binder, which are collectively called the three elements of an abrasive belt. Classification of abrasive belts Due to the differences in the three major components of abrasive belts and various characteristic factors, abrasive belts can be divided into many varieties according to different grinding objects, grinding conditions and grinding requirements. grinding process After nearly thirty years of development, abrasive belt grinding has now become a relatively complete and self-contained new processing technology. It is favored by users because of its high processing efficiency, wide application range, strong adaptability, low cost of use, safe and convenient operation. Abroad, abrasive belt grinding technology has made great progress, and its processing objects and application fields are becoming increasingly extensive. It can process almost all engineering materials, from general daily utensils to large aerospace equipment, and can be used in everything. It has become an important means to obtain significant economic benefits. As a processing technology, it has attracted increasing attention and developed rapidly because it has the following important characteristics: Grinding performance Abrasive belt grinding is a soft grinding method and is a composite processing technology with multiple functions of grinding, grinding and polishing. Abrasive grains for abrasive belts The abrasive grains on the abrasive belt have stronger cutting ability than the abrasive grains on the grinding wheel, so the grinding efficiency is very high. The high efficiency of abrasive belt grinding is reflected in its high removal rate, grinding ratio (the ratio of the weight of the removed workpiece to the weight of the abrasive wear) and the machine tool power utilization. By 2012, the known steel removal rate of abrasive belt grinding has reached 700mm3/mm·s, even exceeding that of turning or milling. The grinding ratio of the abrasive belt greatly exceeds that of the grinding wheel, as high as 300:1 or even 400:1, while the grinding wheel is only 30:1. The power utilization rate of abrasive belt grinders has reached 80% in the early days of the development of abrasive belt grinding, which is ahead of other machine tools. Now it is as high as 96%. In comparison, grinding wheel grinders are only 52%, milling machines are 57%, and lathes are 65%. %, so abrasive belt grinding is still a good energy-saving processing technology. cold grinding Abrasive belt grinding workpieces have high surface quality. In addition to its multiple functions of grinding, grinding and polishing, this is also because: compared with wheel grinding, abrasive belt grinding is known as "cold grinding", that is, the grinding temperature is low and the surface of the workpiece is not easy to appear. Burns, etc. grinding vibration The abrasive belt grinding system has low vibration and good stability. Due to the light weight of the abrasive belt itself, the balance state of the grinding process structure system is easy to control. All rotating parts (such as contact wheels, driving wheels, tensioning wheels, etc.) wear very little, and there will be no dynamic imbalance like the grinding wheel. factor. In addition, the elastic grinding effect of the abrasive belt can greatly reduce or absorb the vibration and impact generated during grinding. The grinding speed is stable, and the abrasive belt drive wheel will not grind at a smaller diameter and slower like a grinding wheel. Roughness The high surface quality of abrasive belt grinding workpieces is mainly reflected in the small surface roughness value, good residual stress state, and no microscopic cracks or changes in the metallographic structure on the surface. From the perspective of surface roughness, abrasive belt grinding has reached Ra0.01mm by 2012, achieving the effect of mirror grinding. For roughness values above Ra0.1mm, it is very easy to achieve. The residual stress on the surface of the workpiece in abrasive belt grinding is mostly in the state of compressive stress, and its value is generally between -60~-5Kg/mm², while the residual stress in grinding wheel grinding is mostly tensile stress, so abrasive belt grinding is very conducive to strengthening the surface of the workpiece and improving the quality of the workpiece. Fatigue strength. Grinding accuracy Abrasive belt grinding has high precision. Due to the improvement in the production quality of abrasive belts and the production level of abrasive belt grinders, abrasive belt grinding has already entered the ranks of precision and ultra-precision processing, with the highest accuracy reaching less than 0.1mm. grinding cost Belt grinding is low cost. This is mainly manifested in: Belt grinding equipment is simple. Compared with wheel grinders, abrasive belt grinders are much simpler. This is mainly because the abrasive belts are light in weight, have small grinding force, and have low vibration during the grinding process. The rigidity and strength requirements of the machine tool are much lower than those of wheel grinders. Abrasive belt grinding is easy to operate and requires little auxiliary time. Whether it is manual or motorized belt grinding, its operation is very easy. From changing and adjusting the abrasive belt to clamping the workpiece to be processed, everything can be completed in a very short time. The abrasive belt grinding ratio is large, the machine tool power utilization is high, and the cutting efficiency is high. This reduces tool and energy costs and takes up less time to remove the same weight or volume of material. Grinding safety Belt grinding is very safe, has low noise and dust, is easy to control, and has good environmental benefits. Since the abrasive belt itself is very light, there is no risk of injury even if it breaks. Abrasive belt grinding is not as serious as grinding wheel sand removal, especially when dry grinding, the grinding debris mainly consists of the material of the workpiece being processed, and the dust is easily recovered and controlled. Due to the use of rubber contact wheels, abrasive belt grinding does not cause a rigid impact on the workpiece like a grinding wheel, so the processing noise is very small, usually <70dB. It can be seen that from an environmental perspective, abrasive belt grinding is also worthy of promotion. The abrasive belt grinding process is highly flexible and adaptable. This manifests itself in: Abrasive belt grinding can be very conveniently used for grinding flat surfaces, internal and external circles and complex curved surfaces. Design an abrasive belt grinding head device as a functional component that can be installed on a lathe for post-turn grinding, or on a planer. It can also be designed into various special grinders. This characteristic of abrasive belt grinding can easily solve the precision machining of some difficult-to-machine parts, such as over-long and over-large shafts and flat parts. There is a wide range of base materials, abrasives, and binders for abrasive belts, which can meet the needs of various uses. Abrasive belts also come in various sizes, lengths and widths, and are available in rolls, rings and other forms. For the same workpiece, abrasive belt grinding can be processed using various grinding methods and process structures. Abrasive belt grinding has an extremely wide range of applications. The superior grinding performance and flexible process characteristics of abrasive belts determine that it has an extremely wide range of applications. From daily life to all walks of life in industrial production, abrasive belt grinding can be found in almost all fields. . Its diverse application forms and wide scope are unmatched by any other processing method. Specifically in: Belt grinding can grind almost any engineering material. In addition to the materials that can be processed by grinding wheel grinding, it can also process non-ferrous metals such as copper and aluminum and non-metallic soft materials such as wood, leather, and plastics. In particular, the "cold" grinding effect of abrasive belt grinding gives it unique advantages when processing heat-resistant and difficult-to-grind materials. 3 Advantages of abrasive belt grinding[edit] Abrasive belt grinding can process workpieces of various shapes with high surface quality and precision requirements. Abrasive belt grinding can not only process common workpieces with flat surfaces and internal and external circular surfaces, but can also process large or special-shaped parts with high surface quality and precision requirements with extremely high efficiency. For example: polishing and grinding of large-area plates. The maximum width of the grinding wheel is only 1000mm, while the width of the abrasive belt can be more than 2500mm. As of 2012, the widest known belt grinder uses abrasive belts up to 4900mm. In actual use, the common processing width of abrasive belt grinding is 50~2000mm, and the processing thickness is 0.4~150mm. Its productivity is as high as 1000m2/h. This kind of wide abrasive belt grinding can be widely used on steel plates, stainless steel plates, silicon steel sheets, aluminum plates, copper plates, particle boards, plywood, medium density fiberboards, leather, insulation boards, ceramic plates, as well as aerospace equipment, ships and nuclear physics research equipment Surface processing of various high-precision and low-roughness large-scale plates used. The precision machining of intermittent planes such as the section of the engine gearbox body can also be formed by grinding with a wide abrasive belt, and can ensure better sealing than the surface processed by traditional milling and planing. Continuous polishing and grinding of metal strips or wires. Due to the development of wide abrasive belt grinding, thin strips have the same grinding conditions across the entire width, so that local excessive force will not occur and stress deformation will occur. Therefore, cold-rolled steel strips, copper, aluminum strips and other The surfaces of alloy strips, etc. are suitable for continuous polishing with abrasive belts. The processing width is 600~2100mm, the processing thickness is 0.1~2.2mm, the surface roughness value is Ra3.2~0.1mm, and the strip running speed is 3~80m/min. Planetary belt grinding provides a very effective and economical processing method for polishing coiled wire rods of stainless steel or other materials. The known wire polishing diameter is 0.8~20mm. The continuous operating speed is 6~150m/min. Polishing the inner and outer circles of workpieces with a large aspect ratio. In modern industry, it is very convenient to use abrasive belt grinding to process the outer circumference of shaft workpieces and the inner circumference of pipe workpieces with large aspect ratios. Generally, this can be achieved by adding an abrasive belt grinding device to large standard equipment. For large batches, a special belt grinder can be used. For example, the outer circumference of workpieces such as large generator rotors, rolls, paper drying cylinders, etc., and the inner circumference surface processing of workpieces such as cylinders, oil pipelines, and pressure vessels. Polishing and polishing of complex special-shaped workpieces. Form grinding of curved workpieces is more difficult. However, the flexibility of the abrasive belt can be used to easily process various complex curved surfaces. The abrasive belt can also polish internal fillets with a curvature radius of only 3mm. For example, aircraft engine blades, turbine blades, navigation blades, condenser lamp bowls, reflectors, tableware, handles, plumbing appliances, etc. can all be polished with high efficiency and high quality using abrasive belts. Abrasive belt grinding equipment comes in many forms and varieties. It can be performed on a variety of general-purpose belt grinding equipment. General-purpose belt grinding equipment includes small ones such as portable belt machines, universal belt machines, and desktop belt machines; large ones include cylindrical belt grinders, plane belt grinders, centerless belt grinders, and internal cylindrical belt grinders, etc. wait. Special abrasive belt grinders include camshaft abrasive belt profile grinders, industrial tank abrasive belt polishers, automobile tire rim end face belt polishers, motorcycle fuel tank abrasive belt polishers, and special stainless steel star basin hair machines. wait.