可编程控制器显示灯外壳的注塑模具设计【一模两腔】【侧抽芯】【说明书+CAD+SOLIDWORKS】
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毕业设计(论文)外文资料翻译系 别 机电信息系 专 业 机械设计制造及其自动化 班 级 B070203 姓 名 王 飞 学 号 B07020319 指导老师 千学明 外文出处Proceedings of the World Congress on Engineering 2009 Vol I WCE 2009,July 1-3,2009 ,london,U.K. 附 件1. 原文:New Cooling Channel Design for for Injection Moulding 2.译文:新型注塑模具冷却通道设计 2011年3月12日New Cooling Channel Design for Injection MouldingA B M Saifullah, S.H. Masood and Igor Sbarski AbstractInjection moulding is one of the most versatile and important operation for mass production of plastic parts. In this process, cooling system design is very important as it largely determines the cycle time. A good cooling system design can reduce cycle time and achieve dimensional stability of the part. This paper describes a new square sectioned conformal cooling channel system for injection moulding dies. Both simulation and experimental verification have been done with these new cooling channels system. Comparative analysis has been done for an industrial part, a plastic bowel, with conventional cooling channels using the Moldflow simulation software. Experimental verification has been done for a test plastic part with mini injection moulding machine. Comparative results are presented based on temperature distribution on mould surface and cooling time or freezing time of the plastic part. The results provide a uniform temperature distribution with reduced freezing time and hence reduction in cycle time for the plastic part.Injection moulding is a widely used manufacturing process in the production of plastic parts 1. The basic principle of injection moulding is that a solid polymer is molten and injected into a cavity inside a mould which is then cooled and the part is ejected from the machine. Therefore the main phases in an injection moulding process involve filling, cooling and ejection. The cost-effectiveness of the process is mainly dependent on the time spent on the moulding cycle in which the cooling phase is the most significant step. Time spent on cooling cycle determines the rate at which parts are produced. Since, in most modern industries, time and costs are strongly linked, the longer is the time to produce parts the more are the costs. A reduction in the time spent on cooling the part would drastically increase the production rate as well as reduce costs. So it is important to understand and optimize the heat transfer process within a typical moulding process. The rate of the heat exchange between the injected plastic and the mould is a decisive factor in the economical performance of an injection mould.A B M Saifullah is a research doctoral student at Industrial Research Institute Swinburne (IRIS), Swinburne University of Technology, Melbourne,Australia (e-mail- msaifullahswin.edu.au), also Member, IAENG. S. H. Masood is a Professor of Mechanical & Manufacturing Engineering at Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Melbourne, Australia. (Corresponding author, ph:+61-3-9214 8260, fax: +61-3-9214 5050, e-mail: smasoodswin.edu.au) Dr Igor Sbarski is a Senior Lecturer at Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Melbourne, Australia.(e-mail: isbarskiswin.edu.au ).Heat has to be taken away from the plastic material until a stable state has been reached, which permits demolding. The time needed to accomplish this is called cooling time or freezing time of the part. Proper design of cooling system is necessary for optimum heat transfer process between the melted plastic material and the mould. Traditionally, this has been achieved by creating several straight holes inside the mould core and cavity and then forcing a cooling fluid (i.e. water) to circulate and conduct the excess heat away from the molten plastic. The methods used for producing these holes rely on the conventional machining process such as straight drilling, which is incapable of producing complicated contour-like channels or anything vaguely in 3D space.An alternative method of cooling system that conforms or fits to the shape of the cavity and core of the mould can provide better heat transfer in injection moulding process, and hence can result in optimum cycle time. This alternative method uses contour-like channels of different cross-section, constructed as close as possible to the surface of the mould to increase the heat absorption away from the molten plastic. This ensures that the part is cooled uniformly as well as more efficiently. Now-a-days, with the advent of rapid prototyping technology such as Direct Metal Deposition (DMD), Direct Metal Laser Sintering (DMLS) and many advanced computer aided engineering (CAE) software, more efficient cooling channels can be designed and manufactured in the mould with many complex layout and cross-sections2,3,4. This paper presents a square section conformal cooling channel (SSCCC) for injection moulding die. Simulation has been done for an industrial plastic part, a circular plastic bowel for these SSCCC and compared with conventional straight cooling channels (CSCC) with Moldflow Plastic Inside (MPI) software. Comparative experimental verification has also been performed with SSCCC and CSCC die for a circular shape test part with mini injection moulding machine for two plastic materials. Result shows that SSCCC die gives better cooling time and temperature distribution than that of CSCC dies.II. DESIGN OF THE PART AND MOULDS A.Part design The part circular plastic bowl made of polypropylene (PP) thermoplastic, as shown in Fig 1(a) has been designed with Pro-Engineer CAD software. It was then exported to IGES (Initial Graphics Exchange Specification) file surface model to import in MPI for analysis. Material volume of the plastic part is 177.90cm3 and its weight is 162.3 gm. Experimental test part as shown in Fig 1(b) has also been designed with Pro-Engineer software. Experimental verification has been done with two types of plastic materials, PP and ABS (Acrylonitrile Butadiene Styrene). Test part volume was 8.8 cm3, and part weight for ABS and PP were 8.68 gm and 8.13gm respectively. B.Mould Design Mould design has been done using Pro/Molde sign module of the Pro/Engineer system. This mould is then manufactured with Computer Numerical Control (CNC) machine. The mould shown in Fig 2 has two parts, the core and the cavity. Square section conformal cooling channel (SSCCC) has been produced around the cavity by CNC machining of one half of the channel on cavity part and the other half on the core part. Both halves are then joined with screws and sealed with liquid gasket (Permatex) to avoid water leakage. III. ANALYSIS AND RESULTS MPI simulation software has been used for part analysis 5. Analysis sequence was flow-cool-warp. Polypropylene plastic material has been used for analysis. Comparative analysis has been done with conventional straight cooling channel (CSCC) and SSCCC. The diameter of CSCC was 12 mm and the length of SSCCC section size was 12 mm (Fig 3). Fusion meshing with global edge length of 0.995 cm has been used. The numbers of mesh elements used were 12944 and 12291 for CSCC and SSCCC respectively. Both cases used cooling medium as normal water of 25C Reynolds number was 10000, melting temperature was 230 C. Comparative analysis result from MPI as shown in Fig 4 shows that SSCCC shows better temperature distribution and less part freezing time than CSCC. In case of CSCC, most of the part cools in about 24 second except the top few areas, while on the other hand SSCCC diagram shows that it is less than 20 seconds. And also CSCC shows the time to freeze range to be sec and SSCCC shows this to be 0.3-87.15sec. So, using SSCCC, 5 second of cooling time has been reduced which is 35% reduction of cooling time.III. ANALYSIS AND RESULTS MPI simulation software has been used for part analysis 5. Analysis sequence was flow-cool-warp. Polypropylene plastic material has been used for analysis. Comparative analysis has been done with conventional straight cooling channel (CSCC) and SSCCC. The diameter of CSCC was 12 mm and the length of SSCCC section size was 12 mm (Fig 3). Fusion meshing with global edge length of 0.995 cm has been used. The numbers of mesh elements used were 12944 and 12291 for CSCC and SSCCC respectively. Both cases used cooling medium as normal water of 25C Reynolds number was 10000, melting temperature was 230 C. Comparative analysis result from MPI as shown in Fig 4 shows that SSCCC shows better temperature distribution and less part freezing time than CSCC. In case of CSCC, most of the part cools in about 24 second except the top few areas, while on the other hand SSCCC diagram shows that it is less than 20 seconds. And also CSCC shows the time to freeze range to be sec and SSCCC shows this to be 0.3-87.15sec. So, using SSCCC, 5 second of cooling time has been reduced whimeIV. EXPERIMENTAL VERIFICATION AND RESULTS Experimental verification has been done with a circular shape plastic test part using the machined mould as shown in Fig 5. Part diameter was 40 mm and thickness was 7 mm. The mould dimension was 10x10x2.5 cm3. Mould material was mild steel. Experiment has been done with a mini injection moulding machine of TECHSOFT mini moulder (Fig 6). Two thermocouples TC08 K type of PICO technology have been used to measure temperature of top and bottom surface of the test part. Melting temperature was 250C for both ABS and PP. Normal water has been used as a cooling medium, room temperature has been measured as 25 C, so is cooling water. Cooling channel diameter was 5 mm for CSCC and SSCCC section size was 5 mm. With two thermocouples, surface temperature of the test part has been measured for every second. From Fig 7 it is noted that for the ABS plastic, using SSCCC, the top face and bottom face of test part cooled earlier than that with CSCC. In case of SSCCC, maximum top and bottom surface temperature recorded at particular time immediately after injection were 53.36 C and 52.1C. After 30 second, this temperature reduced to 42.47 C and 43.07 C, whereas, for CSCC they were 53.24, 52.01 and 47.47, 47.72 C. So in average, 4 to 5 C reduction in temperature happens using the SSCCC. Similar results also have been found when using PP as the part material. From Fig 8, it can be shown that using SSCCC, about 2 to 3C reduction in temperature can be possible. In experimental tests, twenty sample test parts have been produced for ABS and PP material for experimental verification and in every case almost the same data has been found. Fig 9 shows the sample test parts in ABS and PP, which have been produced for experimental verification.V. CONCLUSION The cooling process is one of the most important sub processes in injection moulding because it normally accounts for approximately half of the total cycle time and affects directly the shrinkage, bending and warpage of the moulded plastic product. Therefore, designing a good cooling channel system in the mould is crucial since it influences the production rate and quality. The results of MPI simulation and experimental verification show that using square shape conformal cooling channels gives up to 35% reduction in cooling time and 20% of the total cycle time can be obtained, thus greatly improving the production rate and the production quality of injection moulded parts.ACKNOWLEDGMENT These authors are grateful to Mrs. and Phil Watson of Faculty of Engineering and Industrial Science, Swinburne University of Technology for their technical support for die making with CNC machining. REFERENCES 1 D.V. Rosato, D.V. Rosato and M.G. Rosato, Injection Moulding Handbook-3rd ed , Boston, Kluwer Academic Publishers, (2003). 2 X. Xu, E. Sach and S.Allen, The Design of Conformal Cooling Channels In Injection Moulding Tooling,Polymer Engineering and Science, 4, 1, pp 1269-1272, (2001). 3 D.E. Dimla, M. Camilotto, and F. Miani: Design and optimization of conformal cooling channels in injection moulding tools, J. of Mater. Processing Technology, 164-165, pp 1294-1300, (2005). 4 A B M Saifullah and S. H. Masood, Optimum cooling channels design and Thermal analysis of an Injection moulded plastic part mould, Materials Science Forum, Vols. 561-565, pp. 1999-2002, (2007). 5 A B Saifullah, S. H. Masood and Igor Sbarski, cycle time optimization and part quality improvement using novel cooling channels in plastic injection moulding. ANTECNPE 2009, USA. 新型注塑模具冷却通道设计作者A B M Saifullah, S.H. Masood 和 Igor Sbarski摘要注塑成型是大规模生产塑料零件时最通用并且最重要一种操作方法。在此项工艺当中,冷却系统的设计好坏是非常重要的,因为它很大程度上决定了零件的生产周期。一个良好的冷却系统设计可减少生产周期,并保证零件的尺寸稳定性。本文叙述的是一个注塑膜的冷却通道系统的横切面内容。对这些新的冷却通道系统进行模拟实验。工业园区采用比较分析法,用注塑仿真分析软件分析塑料内部,内部有常见的冷却通道。微注射成型机的塑料零件已得到实验验证。用模具表面温度的分布情况和塑料零件的冷却时间,或是凝固时间相比较分析得到的。结果表明,均匀的温度分布可减少凝固时间,从而减少塑料零件成型周期。1.介绍注塑成型的方法广泛使用于塑料部件的工艺生产当中 1。注射成型的基本原理是,一个固体聚合物熔化后,注入到模具型腔内,冷却之后脱模。因此,主要阶段是注射成型,过程包括填充、冷却和脱模。塑模周期决定生产成本效益高低,而冷却过程是尤为重要的一步。冷却周期决定部件生产效率。因此,在现代工业当中,生产成本和生产时间有密切关系,生产部件的时间越久,成本越高。减少冷却时间可在根本上增加生产效率,并且减少生产成本。因此,理解和优化典型的成型过程即内传热是很重要的。热交换率是塑料注射制品和模具的决定性因素,影响注塑模具的生产业绩。A B M Saifullah是工业研究机构的一名博士生会员, 就读于斯威本国立科技大学,澳大利亚墨尔本人,电子邮件:msaifullahswin.edu.au。IAENG. S. H. Masood的是斯威本国立科技大学机械制造工程系的一名教授, 澳大利亚墨尔本人。联系电话:+ 61-3-9214 8260,传真:+ 61-3-9214 5050,电子邮件:smasoodswin.edu.auIgor Sbarski博士是斯威本国立科技大学机械制造工程系的一名高级讲师,澳大利亚墨尔本人。电子邮件:isbarskiswin.edu.au)。热量必须从塑胶材料上移开,直到达到稳定状态为止后,才可允许脱膜。此过程中需要完成冷却时间或是凝固时间。对于最佳热传递过程来说,在熔融的塑料材料和模具间,恰当的冷却系统设计是很有必要的。在模具型芯和型腔内安装直井眼然后注入冷冻液也就是冰水,使熔融的塑料散热。此方法用于常规机械加工过程中,使用直钻制造这类小孔,而却不能生产像通道或是3D空间这类复杂的孔状。一个冷却系统的替代方法, 在注射模具的过程当中,符合或适合于模具型腔形状和核心形状,才能提供更好的热传递,从而得到最优生产周期。这种方法是用不同横截面相同通道,尽量贴近模具表面减少熔融塑料的热量。这确保零件均匀冷却效率更佳。目前,随着快速成型技术的来临,例如:直接金属沉淀工艺,直接金属激光烧结工艺,还有许多先进的计算机辅助工程软件的,可以给模具设计并制造许多复杂布局和复杂横切面的更高效冷却通道2、3、4。本文介绍了一种方形截面的冷却通道注塑压模,并模仿这种方法生产一种圆形塑料碗,并与使用模拟仿真分析软件制作的直线形冷却通道相比较。用这个方形冷却通道和传统的直线形冷却通道压模来完成这项验证性试验,是为了用微注射成型机制作的模具将一个圆形通道分为两种塑材。结果表明方形冷却通道压模的冷却时间和温度分布都比直线形冷却通道压模有优势。零件和模具设计方面1. 零件设计用聚丙烯制成的圆形塑料碗,如图1(a),采用Pro-Engineer CAD软件设计的。输出初始图形规格模具表面图形文档,在输入到MPI中进行分析。塑料零件体积是177.90和质量是162.3mg。试验测试零件如图1(b),此零件使用Pro-Engineer软件设计出来的。使用Pro-Engineer CAD软件对聚丙烯和丙烯腈这两种类型的塑料材料已做了大量的实验验证。测出零件体积是8.8,聚丙烯部分和丙烯腈部分质量分别为8.58mg和8.13mg。2 .模具设计模具设计当中利用Pro / Molde 设计Pro / Engineer 系统组件。采用计算机数控技术制造模具。图2中所示的模具有两个部分型心和型腔。采用电脑数控技术将方形冷却通道一半设计在型腔部分和另一半设计在型心部分。然后将这两部分用螺丝连接,并用液态填料密封以免漏水。图- 1:CAD模型(a)圆形塑料碗,(b)被测试部分。 图- 2 :CAD模型的核心(上)和两个型腔。3分析结果MPI仿真软件被用来零件分析5。用聚丙烯塑料材料分析注入、冷却、变形这三步顺序。对比分析出方形冷却系统通道与传统的直线形冷却通道的区别。直线形通道的直径为12mm,方形通道长度为12mm(图3)。0.995cm周长的聚变啮合已被应用到工业当中。直线形通道和方形通道的啮合元素的数量分别为12944个和12291个。这两种情况下均使用25标准海水,雷诺数为10000,熔炼温度是230的冷却介质。比较分析MPI结果如图4,从图中看出,直线形通道温度分布比方形通道更为均匀些,而方形通道所需冷却时间相对直线形较少。直线形冷却通道除了顶头部分很小以外,大部分零件冷却时间需要大概24秒,而方形冷却通道图解表明其冷却时间要少于20秒。直线形冷却通道的凝固时间大概在0.46-93.7秒之间,方形冷却通道冷却时间在0.3-87.15秒之间。因此,使用方形冷却通道,需要5秒的冷却时间,冷却时间减少了35%。图- 3 MPI分析,(a):直线型冷却通道,(b):方形冷却通道图4比较二者冷却时间,(a):方形冷却通道(b)直线形冷却通道。4.实验验证结果对一个圆形的塑料零件用模具加工机器实验验证结果如图5所示。零件直径是40mm,厚度是7mm。模具标准尺寸是10x10x2.5。 模具材料是低碳钢。用TECHSOFT迷你模具加工机即一个小型注塑机进行实验验证如图6。两个采用PICO技术生产的TC08 K型热电偶已被用来测量被测试零件的上下表面温度。聚丙烯和丙烯腈的熔解温度均是250C。标准海水已被用来作为冷却介质,由于室温25,所以叫做冷却水。冷却通道直径是5mm,正方形冷却通道和直线型冷却通道标准截面尺寸是5mm。每隔一秒测试一下两个热电偶的表面温度。图7记录了丙烯腈-丁二烯-苯乙烯塑的方型通道顶部和底部的表面比直线型通道更早冷却。方形冷却通道的顶部和底部的表面温度在特定时间立即注射后最高记录是52.1和53.36,30秒后温度分别降低到42.47和43.07,而直线形冷却通道顶部和底部最高温度记录分别是53.24和52.01,30秒后降到温度分别为47.72和47.47。所以,采用方形通道温度平均可降低4到5。用聚丙烯作为零件的材料时实验也发现有类似的结果。从图8可看出使用方形冷却通道时, 温度可能降低2 到3。实验测试出20个样品是由丙烯腈-丁二烯-苯乙烯材料制成的,发现样品都具有相同的数据。图9记录了丙烯腈-丁二烯-苯乙烯样品试验和聚丙烯实验验证结果图- 5:(a)低碳钢核心(左)(b)低碳钢直线形和正方形冷却通道模具型腔图6测试注塑实验装置,左:迷你装置,右: PC输出温度。图7 ABS温度比较图图- 8:聚丙烯温度比较图图- 9抽样检测,左:ABS塑料,右:聚丙烯塑料。4.结论注射成型过程转换到冷却过程是至关重要的一步,因为冷却时间通常约占总周期的一半,从而直接影响到模具塑料产品的收缩和弯曲程度。因此,在模具设计当中一个良好的冷却通道系统是至关重要的,因其影响生产效率和产品质量。MPI仿真结果和实验验证表明使用方形冷却通道可减少35%的冷却时间,总周期20%的时间可大大提高注射模零件的生产效率和生产质量。鸣谢这些作者都要感谢来自沃森工业工程学院的Meredith女士和Phil Watson。他们得到了斯威本国立科技大学的电脑数控生产模具技术的支持。参考文献1 D.V.Rosato, D.V.Rosato和M.G. Rosato,注塑成型手册第三页,波士顿,英文文献(2003)。2 X. Xu, E. Sach 和S.Allen,注塑模具冷却通道的适形设计,聚合物工程科学,4, 1, 1269-1272,(2001)。3 D.E. Dimla, M. Camilotto, and F. Miani:注射成型冷却通道的工具的设计和优化,J.变形。材料科学论坛,容量: 561-565,聚丙烯。1999-2002, (2007)。4一个B和s . h . Masood M Saifullah、优化设计和热分析冷却通道的注射模塑料零件模具,材料科学论坛,由561-565 1999 - 2002年,页。(2007)。5 A B Saifullah, S. H. Masood和Igor Sbarski,塑料注射成型时使用新型冷却通道优化周期时间和改进零件质量。ANTECNPE 2009年,美国。
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