Compared with metal gears, plastic gears have the advantages of light weight, low working noise, wear resistance, no need for lubrication, easy be formed into more complicated shapes and low mass production cost. However, due to the shrinkage and water absorption of plastic itself, the strength is weak and it has the disadvantages of low transmission accuracy and short life. However with the development of mold design and manufacturing technology, the precision of plastic gears continues to improve, making it precision to higher level.
JGMA 116-02 is the Japanese plastic molding gear standard and ANSI/ AGMA 1106-A97 is the USA plastic molding gear standard. they are general same but with some difference too. the plastic gear precision start from 1 to 12. 1 is the highest precision level and 12 is the lowest level. the normal plastic gear precision standard are the 4, 5 and 6 level.
Here let Asia Billion show you more of our experience for the above picture showing plastic spur gear mould what we made several years ago. Because of the non-disclosure agreement for 3 years, we have to show you the picture after the time is expired. It is important for both of Asia Billion and our customer design protection.
The material is polyoxymethylene with mineral (POM+MF) which have good comprehensive mechanical properties. It's mechanical properties is very little with temperature, friction coefficient is small, wear resistance and self-lubricity are very good. However, the range of molding temperature is narrow, the shrinkage rate is large and warpage is easy to occur, which has a great influence on the transmission accuracy of the gear. The amount of warpage must be strictly controlled during molding. and this project we use the POM with mineral filled engineering plastic , it reduce the shrinkage and risk for warpage.
The mold adopts the structure as four cavities, considering the strength of the cavity and the consistency of the flow length when filling the material, we need the flow length from the center of each cavity to the center of the mold is equal; the outer surface of the gear is used for transmission, requirements smooth surface finishing, no gating marks, so the gate can only be placed on the upper and lower surfaces, the 1.0 mm step has the same cylindrical requirements as the outer surface of the gear, so the gear is placed on the side of the mold core side and the upper surface is selected. The parting lines are at the top surface, and the 4 pin point gates are used to automatically running during production with a robot.
The molded parts in the injection mold mainly have a core and a cavity. In order to ensure the coaxiality of the gear, the parting surface is placed on the top surface of the gear. The entire cavity is on the side of the moving mold, which is convenient for ejecting the plastic parts. The inner hole of the upper surface of the plastic gear is chamfered, which is convenient for processing and maintenance. It is disassembled into inserts, and the cavity with the tooth profile part is processed by slow wire cutting processing. the ejector system use the ejector sleeves and ejecotor pins at the plastic gear bottom surface. The gear is a round part, and the size is not large, but high requirements and high precision, many mold makers don't have the capacity to make the plastic gear molds.
Asia Billion company overview:
Plastic spur gear mold usually need to use Moldflow software to simulate plastic gear molding process parameters, design orthogonal experiments to obtain the warpage deformation of plastic parts under different parameter conditions, and range calculation to analyze the degree of influence of different molding parameters on warpage to obtain the best solution of the molding process; using PROE or NX-UG and other software to complete the design of the mold and molding parts, and the structural design of the overall mold with correct solution. For this project , we use the hot runner system in order to make sure to get higher quality and save the molding material. the very small size plastic gear normally need one pin point gate , the middle and big size normally need 2 to 4 pieces pin point gate..
Most low-end plastic gear molds can be produced in China, but the high-end gear molds are mostly imported. There are not many factories specializing in gear molds in China. Most gear factories make gear molds by themselves. Gear factories often set up a workshop to take this work. This makes the development of the domestic gear mold industry even more difficult. In order to promote better and faster development of Chinese gear mold industry, we must fundamentally solve the problem of dependence and strive to improve professional technology in order to better serve the domestic gear mold industry. As the competition in the gear industry continues to intensify, mergers, acquisitions, integration and capital operations among large gear companies are becoming more and more frequent. Excellent domestic gear manufacturers are paying more and more attention to the research on the industry market, especially in-depth development of the enterprise development environment and customer demand trends. Asia Billion are trying our best to learn the technology and support our global customer for the plastic gear mold making.
Plastic spur gear mould is usually the simplest in plastic gears, and are often the first projects that manufacturers who first enter the plastic gear mold manufacturing industry and familiarize with gear mold structures. Asia Billion is no exception. We start from a few years ago. From simple spur gear injection mold manufacturing to the current helical gear injection mold, turbo screw gear injection mold manufacturing, we have experienced countless successes and failures, and have drawn a lot of experience, thus laying us today as a professional plastic gear manufacturer A solid foundation. Asia Billion would like to thank all the friends who have been helping and supporting us for all the customers and the supplier team !
Contact Asia Billion freely if we can help you for your plastic gear mold project !