With the national plan for Made in China 2025 and the strengthening of environmental management, coupled with the disappearance of the demographic dividend, all walks of life are improving manufacturing technology, and the grinding process that was often ignored in China's sheet metal stamping industry has finally made great progress in recent years. The grinding process described in this article refers to the grinding, deburring, chamfering, wire drawing, slag cleaning, polishing and other processes in the field of metal processing.

Hand grinding

In the past few decades of production process, grinding process is usually implemented by manual processing tools, scrapers, files, electric, pneumatic tools, etc. (Figure 1), the problems in this way are obvious: low efficiency, low quality, poor environment, and even great safety risks, Kunshan Zhong Rong explosion is a typical large-scale manual polishing caused by major accidents. Nowadays, even without a safe and healthy environment, few young people are willing to do such dirty, tiring and health-threatening work.

longitudinal wide wire drawing machine

The traditional longitudinal wide wire drawing machine (FIG. 2) that appeared in the early market replaced part of the manual drawing activities. The main feature of this kind of equipment is that the sand belt is tensioned on two belt wheels, the grinding wheel exerts pressure on the inside of the sand belt, and the sand grain of the sand belt is ground against the workpiece. Because the workpiece feed direction is in the same direction as the sand belt operation direction, it is easy to cause inconsistent grinding force on the workpiece surface due to uneven grinding of the sand belt, resulting in the phenomenon of "Yin and Yang face". When processing hard burrs, it is easy to cause burrs on the workpiece contour edge to be pushed into the hole and the burr is not clean, and it is easy to cut the sand belt, seriously shorten the service life of the sand belt, and increase the user's use cost.

ZDM-TK series narrow sand belt deburring machine

In response to the process defects of the wide belt sanding machine, in 2014, Suzhou Shinetek Grinding Technology Co., Ltd. was the first in China to launch the ZDM-TK series equipment specifically for removing hard burrs (Figure 3). Compared to traditional wide belt sanding machines, the TK model adopts narrow belt sanding, with feeding perpendicular to the grinding direction. The sanding belt grinds hard burrs, flanges, and slag on the surface of the parts in layers from high to low, and the grinding force is dynamically adjusted. Therefore, while removing burrs, the sanding belt is uniformly ground without being cut, and the service life of the sanding belt is greatly improved, effectively reducing the cost of use. At the same time, a bi-directional rotating sand block structure has been added to the rear of the equipment. The sand block adopts a small narrow strip sand belt structure, which can penetrate deep into the small hole, grind and chamfer the inner and outer contours, and achieve the function of removing hard burrs and chamfering in one feed. The emergence of this technology and equipment has greatly improved the quality and efficiency of burr removal process after laser and other thermal processing, and can be called an innovative product of grinding technology.

ZDM-R series universal roller brush type deburring machine

In response to the higher grinding demand in the precision sheet metal stamping industry, Suzhou Shinetek Grinding Technology Co., Ltd. once again pioneered the ZDM-R series universal roller brush type deburring machine in China in 2015 (Figure 4). This equipment utilizes the characteristics of flexible grinding with abrasive belts and adopts a roller brush structure to allow the abrasive mechanism to rotate 360 ° while also performing high-speed grinding on the inner and outer contour edges. It achieves the removal of burrs while chamfering the contour edges. At the same time, it independently develops vacuum suction automation transmission technology to meet the needs of simultaneous processing of large and small workpieces. The intelligent abrasive compensation control technology achieves foolproof and unmanned operation, The self-cleaning function meets safety and environmental protection requirements. This series of equipment can also be equipped with a data sharing interface, which can effectively connect with the factory ERP management system. It not only achieves uniform deburring of the internal and external contours of the parts, but also meets the requirements of intelligent, efficient, environmentally friendly, and safe production in the factory.

ZDM-BR series and ZDM-TR series models

With the development of the market, the needs of customers are more diversified, shinetek has successfully launched the ZDM-BR series (Figure 5) and ZDM-TR series models (Figure 6).

The ZDM-BR series combines the traditional wire drawing machine structure with the roller brush deburring structure, integrating Shineek's independently developed high-precision pressure control technology for wide sand belts and R series related intelligent control technology. It synchronously realizes wire drawing and chamfering, meeting the customer's requirements for presenting both the quality and appearance of parts.

The ZDM-TR series models combine the characteristics of TK sand belt grinding control technology and R series universal roller brush technology, achieving the effect of removing hard burrs and large slag, evenly chamfering, and forming long straight lines on the surface. This has once again promoted the further development of flat grinding technology.

ZDM-STK series models

The traditional sheet metal stamping industry mainly focuses on thin plate processing, but in the heavy industry, medium and thick plate processing is more common. The cutting process is mostly high-power laser, flame, and plasma cutting. The slag after cutting is often polished or knocked away by hand tools, because the workpiece is heavy, transportation and operation are extremely inconvenient and unsafe. After hot processing, most parts in this industry undergo deformation, but the requirement is not only to remove slag, but also to chamfer the contour and not damage the surface oxide layer of the workpiece, which poses new challenges to grinding technology. Suzhou Shinetek Grinding Technology Co., Ltd. has developed the ZDM-STK series of products specifically designed for slag cleaning needs (Figure 7). This product adopts CNC hammering technology, a special small hammer structure, and a self-developed workpiece deformation adaptive system. Combined with Shinetek's mature TK series sand belt flexible grinding technology, it can not only indiscriminately strike the contour of hot processed deformed workpieces, remove slag, but also achieve chamfering without damaging the surface oxide layer, perfectly solving the problem of slag removal in the heavy industry.

Weld seam grinding and 3D surface grinding equipment

The demand for grinding in the market is diverse, and in addition to flat product grinding, more complex grinding needs are reflected in the fields of weld seam grinding and trajectory polishing of three-dimensional curved surfaces and casting products. Fortunately, in the field of weld seam polishing, several domestic companies have developed a series of linear weld seam polishing equipment for container products by combining the self-control technology of CNC machine tools with traditional sand belt or disc grinding processes, as shown in Figures 8 and 9. This has pioneered the technology of replacing manual weld seam polishing with domestic equipment, and its automation, polishing consistency, and other characteristics far exceed manual operation, winning customer recognition and worthy of recognition and promotion.

Robot grinding

The demand in the field of grinding, we can say it is very broad. With the rapid development of domestic industry, this market has just opened, and the application of robot technology is gradually being promoted in this field (Figure 10). Not long ago, the globally renowned company 3M held the China Robot Grinding Innovation Summit in Shanghai. According to statistics from the China Robotics Industry Association at the meeting, the largest industry in which robots are currently used is logistics and transportation, with 31% being used. The second largest application is the welding industry, with 21% being used. 3M and KUKA believe that "polishing, polishing, and deburring will reach the same market size as welding, with a market size of 30000 units or even more by 2023.". This will undoubtedly be an era of rapid development in the grinding market, grinding technology, and grinding equipment.

Closing remarks

With the wave of global economic integration, China's various technologies and equipment are also catching up and constantly improving. The development of grinding technology has never stopped, but there is still a significant gap between us and advanced foreign grinding technologies. We still need to focus on researching and improving grinding materials, grinding processes, mechanical control, online detection and other technologies. The field of grinding not only requires the improvement of professional technology, but also needs to be closely connected with digital technology in industrial manufacturing, to elevate grinding equipment to a height of intelligence and industrialization, empower the vast metal processing industry, and contribute to China's manufacturing in 2025.

--Excerpted from Sheet Metal and Manufacturing, Issue 1, 2020