Injection molding is one of the most widely used material processing methods in producing plastic products with complex geometries and high precision. The determination of process parameters is important in obtaining ...Injection molding is one of the most widely used material processing methods in producing plastic products with complex geometries and high precision. The determination of process parameters is important in obtaining qualified products and maintaining product quality. This article reviews the recent studies and developments of the intelligent methods applied in the process parameter determination of injection molding. These intelligent methods are classified into three categories： Case-based reasoning methods, expert sys- tem-based methods, and data fitting and optimization methods. A framework of process parameter determination is proposed after comprehensive discussions. Finally, the conclusions and future research topics are discussed.展开更多
Compared with conventional injection mold- ing, injection-compression molding can mold optical parts with higher precision and lower flow residual stress. However, the melt flow process in a closed cavity becomes more...Compared with conventional injection mold- ing, injection-compression molding can mold optical parts with higher precision and lower flow residual stress. However, the melt flow process in a closed cavity becomes more complex because of the moving cavity boundary during compression and the nonlinear problems caused by non-Newtonian polymer melt. In this study, a 3D simulation method was developed for injection-compres- sion molding. In this method, arbitrary Lagrangian- Eulerian was introduced to model the moving-boundary flow problem in the compression stage. The non-New- tonian characteristics and compressibility of the polymer melt were considered. The melt flow and pressure distribution in the cavity were investigated by using the proposed simulation method and compared with those of injection molding. Results reveal that the fountain flow effect becomes significant when the cavity thickness increases during compression. The back flow also plays an important role in the flow pattem and redistribution of cavity pressure. The discrepancy in pressures at different points along the flow path is complicated rather than monotonically decreased in injection molding.展开更多
Near-net shaping is an efficient, economical and environmentally-friendly approach to manufacture products which are very close to the final shape, reducing the need for surface finishing. It has become more and more ...Near-net shaping is an efficient, economical and environmentally-friendly approach to manufacture products which are very close to the final shape, reducing the need for surface finishing. It has become more and more important to use raw materials and energy in an optimal way. Near-net shaping technology has attracted increasing attention in both academic and industrial communities, especially in China, because China has become the world＇s largest regional market for main material forming methods, such as casting, forging and injection molding. The main objective of this special issue in Frontiers of Mechanical Engineering is to bring together the leading ideas, experience and research results of academic scientists and researchers on various aspects of near-net shaping technology. This special issue contains eleven papers contributed by prestigious experts from different countries, including four reviews and seven research articles. These papers cover a broad area of the near-net shaping technology,展开更多
基金The authors would like to acknowledge the financial support from the National Natural Science Foundation of China （Grant Nos. 51675199 and 51635006） and the National Program on Key Basic Research Project （Grant No. 2013CB035805）.
文摘Injection molding is one of the most widely used material processing methods in producing plastic products with complex geometries and high precision. The determination of process parameters is important in obtaining qualified products and maintaining product quality. This article reviews the recent studies and developments of the intelligent methods applied in the process parameter determination of injection molding. These intelligent methods are classified into three categories： Case-based reasoning methods, expert sys- tem-based methods, and data fitting and optimization methods. A framework of process parameter determination is proposed after comprehensive discussions. Finally, the conclusions and future research topics are discussed.
基金The authors would like to acknowledge the financial support from the National Natural Science Foundation of China （Grant Nos. 51635006 and 51675199）, the Fundamental Research Funds for the Central Universities （Grant Nos. 2016YXZD059 and 2015ZDTD028）, and the Beijing Engineering Research Center of Advanced Structural Transparencies for the Modem Traffic System.
文摘Compared with conventional injection mold- ing, injection-compression molding can mold optical parts with higher precision and lower flow residual stress. However, the melt flow process in a closed cavity becomes more complex because of the moving cavity boundary during compression and the nonlinear problems caused by non-Newtonian polymer melt. In this study, a 3D simulation method was developed for injection-compres- sion molding. In this method, arbitrary Lagrangian- Eulerian was introduced to model the moving-boundary flow problem in the compression stage. The non-New- tonian characteristics and compressibility of the polymer melt were considered. The melt flow and pressure distribution in the cavity were investigated by using the proposed simulation method and compared with those of injection molding. Results reveal that the fountain flow effect becomes significant when the cavity thickness increases during compression. The back flow also plays an important role in the flow pattem and redistribution of cavity pressure. The discrepancy in pressures at different points along the flow path is complicated rather than monotonically decreased in injection molding.
文摘Near-net shaping is an efficient, economical and environmentally-friendly approach to manufacture products which are very close to the final shape, reducing the need for surface finishing. It has become more and more important to use raw materials and energy in an optimal way. Near-net shaping technology has attracted increasing attention in both academic and industrial communities, especially in China, because China has become the world＇s largest regional market for main material forming methods, such as casting, forging and injection molding. The main objective of this special issue in Frontiers of Mechanical Engineering is to bring together the leading ideas, experience and research results of academic scientists and researchers on various aspects of near-net shaping technology. This special issue contains eleven papers contributed by prestigious experts from different countries, including four reviews and seven research articles. These papers cover a broad area of the near-net shaping technology,
