The plastic gear industry issued the first standard in China

The plastic gear industry ushered in the first national standard. Recently, the National Standardization Administration officially released the national standard for the precision of plastic gears, GB/T38192-2019 Definition and Allowable Values of the Precision of Injection Molding Plastic Cylindrical Gears - Tooth Profile Deviation on the Same Side and Radial Composite Deviation. Dr. Changshi Zhaoyao, the drafting group of the plastic gear precision standard, said that after the review of the National Technical Committee for Gear Standardization, the standard filled the gap and reached the international advanced level, which is what the plastic gear industry has been looking forward to for decades.

Establishing standards is the demand of mature markets

As one of the most widely used mechanical transmission devices, gear has a long history of development. Since the successful development of fiber nylon in 1935, the polymer synthetic material industry has developed rapidly. A new type of material has been applied to gears, forming plastic gears. Compared with metal gear, plastic gear has the advantages of light weight, small inertia, low noise, self lubrication, etc. Its products are processed by open die, with high production efficiency and low cost. After decades of development, they have been widely used in various industries such as automobile electrical equipment, instruments and meters, service robots, household appliances, office automation, smart home and so on. Especially in the past two decades, with the successful development and modification of engineering plastics with high strength, high wear resistance and other high performance, plastic gears are developing towards the direction of bearing higher loads. The application of plastic gears is further expanded, and there is a trend of "replacing steel with plastic" in many fields. It can be said that the rapid development of plastic gears is a worldwide trend in the field of gears.

However, since the development and application of plastic gear has been growing, there is no plastic gear standard in China, especially the lack of the most basic plastic gear accuracy standard, which seriously restricts the development of the plastic gear industry in China. At present, there is still a certain gap between the manufacturing level of plastic gears and that of developed countries, resulting in the passive situation that China still needs to import a large number of high-grade plastic gears from abroad. In order to break through this dilemma, it is necessary to study from many aspects, such as gear product design, plastic material research and development, injection mold design and manufacturing, new injection molding equipment and new injection molding process research, gear detection and experiment, and these problems can not be solved without the establishment of a standardized system. However, due to the large differences between plastic gear and metal gear in design requirements, manufacturing methods, application places, etc., the formulation of the precision standard of plastic gear itself is quite complicated, which has become an urgent problem for the gear industry in China.

Promote the overall development of the industry

With the introduction of the precision standard of plastic gear, enterprises in the industry are deeply excited. Shenzhen Zhaowei Electromechanical Co., Ltd., a high-tech enterprise specializing in the R&D and production of precision gear molds, has jointly participated in the formulation of this standard. Li Haizhou, chairman of Shenzhen Zhaowei, said happily, "There has never been a set of tooth molding standards in the industry. In the development process, we can only contact German and Japanese standards. Without standards, we can move forward in the dark. Now we have our own standards, which will bring new light to our tooth molding industry."

The precision standard of plastic gear for injection molding provides a standard basis for measuring, testing and grading products, which is conducive to ensuring the quality and reliability of products, leading to orderly competition and healthy development of products, and promoting continuous innovation and industrial technological progress. It can not only regulate the production behavior of enterprises, establish a benign market order, boost industrial technology progress, but also broaden the procurement channels for enterprises, reduce external dependence, improve work efficiency, and significantly reduce procurement and maintenance costs.

Industry formulation is in line with international standards

In the process of standard formulation, the standard formulation team led by Shi Zhaoyao not only adopted the latest ISO precision standard system, such as terminology, precision grading concept and tolerance calculation formula, but also combined the mature technology and experience in plastic gears in China to form a precision grade calculation, measurement and evaluation system with Chinese characteristics for injection molding gears.

Injection molding gear has its own characteristics, such as small module, one-time molding of tooth shape by mold, stiffened structure, etc. Therefore, the precision and measurement method of injection molded gears cannot be completely equivalent to the ISO 1328 and ISO/TR10064 series standards. Although the precision standard of injection molding gear in China is not equivalent to ISO standard, it is consistent with ISO in macro aspects and is in line with international standards as far as possible. Ouyang Zhixi, the late expert who made a significant contribution to the development of the standard, said, "The primary task is to develop a plastic gear standard that is suitable for China's national conditions, which has both Chinese characteristics and operability."

During the preparation of this standard, the ISO1328 standard and the relevant standards of Japan, the United States and Germany have been thoroughly studied, and the content of this standard has been determined based on the comprehensive consideration of the domestic industry, ensuring the progressiveness of this standard. Wang Zhigang, secretary-general of the National Technical Committee for Gear Standardization, said that it was not easy to formulate the standard. From the project establishment in 2015 to its completion today, it has experienced many difficulties, which is a comprehensive summary of China's plastic gear industry. He hoped that there would be more innovations in the field of small modulus plastic teeth, and he expected to make breakthroughs in the standardization of strength and life tests of plastic teeth in the next step.