编号： 毕业设计(论文)外文翻译（原文）学 院： 国防生学院 专 业： 机械设计制造及其自动化 学生姓名：学 号： 指导教师单位： 姓 名：职 称：2014年 3 月 9 日 桂林电子科技大学毕业设计（论文）外文翻译原文 第38页 共38页Incorporating Manufacturability Considerations during Design of Injection Molded Multi-Material Objects Ashis Gopal Banerjee, Xuejun Li, Greg Fowler, Satyandra K. Gupta1 Mechanical Engineering Department and The Institute for Systems Research University of Maryland, College Park, MD 20742, U.S.A. ABSTRACT The presence of an already molded component during the second and subsequent molding stages makes multi-material injection molding different from traditional injection molding process. Therefore, designing multi-material molded objects requires addressing many additional manufacturability considerations. In this paper, we first present an approach to systematically identifying potential manufacturability problems that are unique to the multi-material molding processes and design rules to avoid these problems. Then we present a comprehensive manufacturability analysis approach that incorporates both the traditional single material molding rules as well as the specific rules that have been identified for multi-material molding. Our analysis shows that sometimes the traditional rules need to be suppressed or modified. Lastly, for each of the new manufacturability problem, this paper describes algorithms for automatically detecting potential occurrences and generating redesign suggestions. These algorithms have been implemented in a computer-aided manufacturability analysis system. The approach presented in this paper is applicable to multi-shot and over molding processes. We expect that the manufacturability analysis techniques presented in this paper will help in decreasing the product development time for the injection molded multi-material objects. Keywords: Automated manufacturability analysis, generation of redesign suggestions, and multi-material injection molding. 1 INTRODUCTION Over the last few years, a wide variety of multi-material injection molding (MMM) processes have emerged for making multi-material objects, which refer to the class of objects in which different portions are made of different materials. Due to fabrication and assembly steps being performed inside the molds, molded multi-material objects allow significant reduction in assembly operations and production cycle times. Furthermore, the product quality can be improved, and the possibility of manufacturing defects, and total manufacturing costs can be reduced. In MMM, multiple different materials are injected into a multi-stage mold. The sections of the mold that are not to be filled during a molding stage are temporally blocked. After the first injected material sets, then one or more blocked portions of the mold are opened and the next material is injected. This process continues until the required multi-material part is created. Nowadays, virtually every industry (e.g., automotive, consumer goods, toys, electronics, power tools, appliances) that makes use of traditional single-material injection molding (SMM) process is beginning to use multi-material molding processes. Some common applications include multi-color objects, skin-core arrangements, in-mold assembled objects, soft-touch components (with rigid substrate parts) and selective compliance objects. Typical examples of each class of application are shown in Fig. 1. There are fundamentally three different types of multi-material molding processes. Multi-component injection molding is perhaps the simplest and most common form of MMM. It involves either simultaneous or sequential injection of two different materials through either the same or different gate locations in a single mold. Multi-shot injection molding (MSM) is the most complex and versatile of the MMM processes. It involves injecting the different materials into the mold in a specified sequence, where the mold cavity geometry may partially or completely change between sequences. Over-molding simply involves molding a resin around a previously-made injection-molded plastic part. Each of the three classes of MMM is considerably different. Each specific MMM process requires its own set of specialized equipment; however, there are certain equipment requirements that are generally the same for all types of MMM. Techniques described in this paper are applicable to over-molding and multi-shot molding.Currently only limited literature exists that describes how to design molded multi-material objects. Consequently very few designers have the required know-how to do so. Consider an example of a two piece assembly consisting of part A and part B to be produced by multi-material molding. In fact, many new users believe that if part A and part B meet the traditional molding rules then assembly AB will also be moldable using multi-mater