1、PDF外文：http:/ 中文 6400 字 毕业设计 (论文 )外文翻译 （ 译 文） 学 院： 机电工程学院 专 业： 机械设计制造及其自动化 学生姓名：
2、 学 号： 指导教师单位： 艺术与设计 学院 姓 名： &
3、nbsp; 职 称： 讲师 2012 年 5 月 15 日 出处： JOURNAL OF CELLULAR PLASTICS Volume 46 November 2010 The Effects of Mold Designon the Pore Morphology ofPolymers Produced wit
4、hMuCell_ Technology ABSTRACT: In this study two molds were designed and used in MuCell_technology to generate implants with a porous structure. To arrive the desiredpore structure many process parameters were investigated for indicating theeffects of process parameters on the pore morphology.
5、This process parameterinvestigation was performed on each mold respectively, so that the influencesof the mold design on the pore morphology have been researched by the sameprocess parameter setting. It was found that the mold design also had effectson the pore structure in MuCell_ technology. A pro
6、per mold design couldimprove the generated pore structure, such as porosity, pore diameter, andinterconnectivity. KEY WORDS: mold design, cell morphology, MuCell_, injection molding,medical implant, porous polymer, polyurethane. INTRODUCTION MuCell technology, as an effective microcellular injection
7、 moldingprocess, is widely used in automobile and furniture industries.In most cases, MuCell_ technology is used to save raw materials, but itis also used to produce implants with closed porous structure 1. It usesCO2 as blowing agent, which is injected in the plasticization section ofthe injection
8、molding machine (Figure 1). The blowing agent is injectedinto the polymer melt through the gas supply line and injector, in itssuper critical state, by the plasticization phase of the injection moldingmachine. After the plasticization the mixture of polymer melt and gas isinjected through the nozzle
9、 into the mold, where the foam structure canbe generated due to the quick pressure drop in the mold. The mainproducts which are produced today with MuCell_ technology have closedcellular foam 24. The MuCell Microcellular Foam injection molding technology is a complete process and equipment technolog
10、y which facilitates extremely high quality and greatly reduces production costs. The MuCell Process involves the controlled use of gas in its supercritical state to create a foamed part. The MuCell Technology is targeted at precision and engineered plastic components with maximum wall thicknes
11、ses of less than 3mm.The MuCell Process generally offers a 50-75% improvement in key quality measures, such as flatness, roundness, and warpage, also eliminating all sink marks. These improvements result from the fact that relatively uniform stress patterns are created in the molded part rather than
12、 non uniform stress characteristic of solid molding.As a direct result of the uniform stress and shrinkage associated with the MuCell Process (which occurs because the pack and hold phase of the molding cycle is eliminated), the parts that are produced tend to comply far more closely with the mold s
13、hape and, presumably, the dimensional specifications of the part itself. This means that when using the MuCell Process, fewer mold iterations are needed to produce a compliant part, saving time and cost.The quality advantages of the MuCell Process are complemented by certain direct economic advantag
14、es, including the ability to produce 20-33% more parts per hour on a given molded machine, and the ability to mold parts on lower tonnage machines as a result of the viscosity reduction and the elimination of the packing requirement that accompanies the use of supercritical gas. This 25 page process
15、ing handbook covers all aspects of the process from set-up to troubleshooting to optimizing results. It is primarily useful to companies who are manufacturing or are planning to manufacture parts using the MuCell Injection Molding Process. Please contact Trexel for a copy of this publication.The MuC
16、ell Injection Molding Process involves the highly controlled use of gas in its supercritical state (SCF) to created millions of micron-sized voids in thin wall molded parts (less than 3mm). With the correct equipment configuration, mold design, and processing conditions these microcellular voi
17、ds are relatively uniform in size and distribution.The voids are created or nucleated as a result of homogeneous nucleation that occurs when a single-phase solution of polymer and gas (commonly nitrogen, but occasionally carbon dioxide) passes through the injection gate into the mold.The single-phas
18、e solution is created through the operation of a conventional injection molding machine which has been modified to allow the creation of a single-phase solution. The key modifications to the system involve the use of a precision SCF delivery system to deliver SCF to special injectors based on
19、mass flow metering principles. The SCF is then injected into the barrel where it is mixed with the polymer via a specially designed screw. A shut off nozzle maintains the single phase solution while the injection molding screw maintains sufficient back pressure at all times to prevent pr
20、emature foaming or the loss of pressure which would allow the single phase solution to return to the two phase solution. Trexel has recently published a comprehensive MuCell Process Guide in English, Chinese, Japanese, and German which explains in step by step detail how to apply the MuCell pr
21、ocess in the manufacture of MuCell Injection Molded components. This 25 page processing handbook covers all aspects of the process from set-up to troubleshooting to optimizing results. It is primarily useful to companies who are manufacturing or are planning to manufacture parts using the MuCell Inj
22、ection Molding Process. Please contact Trexel for a copy of this publication.The MuCell microcellular foam injection molding process for thermoplastics materials provides unique design flexibility and cost savings opportunities not found in conventional injection molding. The MuCell process allows f
23、or plastic part design with material wall thickness optimized for functionality and not for the injection molding p r o c e s s . T h e c o m b i n a t i o n o f d e n s i t y reduction and design for functionality often results in material and weight savings of more th
24、an 20%. By replacing the pack & hold phase with cell growth, lower stress parts are produced which have enhanced dimensional stability and substantially reduce warpage. Cell growth also r e s u l t s i n t h e e l i m i n a t i o n o f s i n k m a r k s
25、 . Unlike chemical foaming agents, the physical MuCell process has no temperature limitation and does not leave any chemical residue in the polymer； making consumer products perfectly suitable for recycling within the original polymer classification and allowing re-grind material to reenter the process flow. The numerous cost and processing advantages have led to rapid global deployment of the MuCell process primarily in automotive, consumer electronics, medical device, packaging
