As a new technology, sand belt grinding is widely favored due to its high processing efficiency, wide application range, strong adaptability, low operating cost, and safe and convenient operation. It has been widely used abroad and developed rapidly, competing fiercely with traditional turning, milling, and grinding wheel grinding. The productivity of sand belt grinding is 10 times higher than milling and 4-10 times higher than grinding wheel grinding. Sand belt grinding is increasingly widely used in the grinding and polishing of various materials, especially suitable for processing large thin plates, strips, thin-walled holes with large aspect ratios, and outer circles. At present, sand belt grinding technology is constantly developing with the improvement of sand belt manufacturing quality and the development of varieties. In industrialized countries such as the United States, the United Kingdom, Japan, Germany, etc., the production of sand belt grinding machines and sand belts is increasing day by day. China is also paying more and more attention to this research, attracting more and more universities, research institutions, and industrial and mining enterprises to study and apply this advanced technology. Its superiority has gradually been recognized by people. If this new technology is further promoted and applied, it will have a significant impact on China's manufacturing industry, and will also play an important role in reducing costs, improving efficiency, and enhancing product processing accuracy for enterprises.

1 sand belt

Sand belt is a special form of multi blade cutting tool, whose cutting function is mainly completed by abrasive particles adhered to the substrate. As a cutting behavior of an abrasive grain, it can be compared to the cutting behavior of a micro body of a general cutting tool. Sand belt is a type of single-layer abrasive grinding tool, which is the main body of sand belt grinding. It consists of three elements: abrasive, binder, and substrate material. On the surface of a flexible and extremely flat fabric or paper substrate, long diameter standing abrasive particles are arranged flat, and the flexibility and elasticity are maintained by the binder and substrate material. As the main variety of coated grinding tools, its performance is formed by the comprehensive composition of various elements. Due to the different compositions of these elements, the performance of sand belts as coated grinding tools can meet the requirements of grinding different workpiece materials under different processing conditions. At the same time, it also forms many advantages that distinguish sand belt grinding from grinding wheel grinding

2. Sand belt grinding

Sand belt grinding is a new process that uses sand belts to gradually remove or smooth the excess material on the machined surface of the workpiece by contacting the high-speed running sand belt with the workpiece surface in a corresponding way and under a certain pressure, according to the requirements of the workpiece to be machined on a certain mechanical device. During the relative motion between the abrasive particles and the workpiece surface, there is a certain degree of interference between the abrasive particles and the workpiece surface. According to the degree of interference, it can be divided into three different processes.

(1) Sliding friction actually begins to contact the workpiece at this point, with little interference. The abrasive particles only rub against the surface of the workpiece, playing a "sliding friction" role. At this time, the abrasive particles slide on the workpiece, actually producing elastic and plastic deformation of the material being cut off.

(2) With the feed of the machine tool and the increase of cutting thickness, the interference of the plow increases. At this time, the abrasive particles plow "grooves" on the surface of the workpiece, which is called the "plow". At this point, the workpiece material undergoes plastic flow, and the material undergoes a squeezing motion, squeezing out from the front and both sides in the direction below the abrasive grain, while cutting off a small amount of material.

(3) Under a certain pressure, when there is sufficient interference and accompanied by a certain cutting temperature, true "cutting" begins. At this time, fractures occur in front of the sliding abrasive particles, forming chips with a relatively fast cutting rate. The numerous abrasive particles on the sanding belt, at the moment of contact with the workpiece, some of the abrasive particles perform cutting, others plow out grooves, and some only play a sliding role. Even different parts of the same abrasive particle and the same part play different roles at different processing times. In addition, the rotational motion of the sand belt also plays a role in wiping away the chips, removing the chips in front of the advancing abrasive particles.

Advantages of Sand Belt Grinding

(1) The selected needle shaped sand particles are polished using advanced "electrostatic sand belt grinding technology and electrostatic sand planting method", which ensures that the sand particles are evenly upright on the substrate, with the sharp edge facing upwards and arranged in a neat orientation, with good uniformity, large chip gap, small contact surface, and good cutting performance. The application of this multi blade cutting tool for grinding processing results in high production efficiency.

(2) When grinding with sand belts, the contact surface is small and the friction heat is low, which can effectively reduce the deformation and burn of the workpiece. The machining accuracy is high. The sand belt has flexible contact during grinding, and has multiple functions such as grinding, grinding, and polishing. In addition, the small vibration of the grinding system and stable grinding speed make the surface machining quality roughness value small and the residual stress state good. The roughness of the workpiece can reach Ra0.4-0.1 μ m, and the surface has uniform roughness, resulting in high machining surface quality.  

(3) Sand belt grinding can be used for flat, outer circle, inner circle grinding, and complex irregular surface machining. In addition to various general and specialized equipment, designing a sand belt grinding head can be easily installed on conventional ready-made equipment such as lathes and milling machines. This not only greatly expands the functions of these machine tools, but also solves the precision machining of difficult to machine parts such as ultra long, ultra large shafts, flat parts, irregular surfaces, etc. The sand belt grinding process is flexible and adaptable.   
It is precisely by utilizing the advantages of sand belt grinding that we have made the sand belt into a wheel shaped coated grinding tool and applied it to the polishing of stainless steel pipes, solving the problems of easy burning and insufficient rigidity on the surface of stainless steel pipes.