3010 可編程控制器顯示燈外殼的模具設計

3010 可編程控制器顯示燈外殼的模具設計,可編程控制器,顯示,外殼,模具設計 畢業(yè)設計(論文) 外文資料翻譯系 別 機電信息系 專 業(yè) 機械設計制造及其自動化 班 級 B070203 姓 名 王 飛 學 號 B07020319 指導老師 千學明 外文出處 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.譯文:新型注塑模具冷卻通道設計 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- msaifullah@swin.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: smasood@swin.edu.au) Dr Igor Sbarski is a Senior Lecturer at Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, Melbourne, Australia.(e-mail: isbarski@swin.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-sections[2,3,4]. 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 MOULDSA.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 25°C 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 25°C 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 RESULTSExperimental 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 250°C 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 52.1°C. 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 3°C 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. ANTEC@NPE 2009, USA. 新型注塑模具冷卻通道設計作者A B M Saifullah, S.H. Masood 和 Igor Sbarski摘要注塑成型是大規(guī)模生產(chǎn)塑料零件時最通用并且最重要一種操作方法。在此項工藝當中,冷卻系統(tǒng)的設計好壞是非常重要的,因為它很大程度上決定了零件的生產(chǎn)周期。一個良好的冷卻系統(tǒng)設計可減少生產(chǎn)周期,并保證零件的尺寸穩(wěn)定性。本文敘述的是一個注塑膜的冷卻通道系統(tǒng)的橫切面內容。對這些新的冷卻通道系統(tǒng)進行模擬實驗。工業(yè)園區(qū)采用比較分析法，用注塑仿真分析軟件分析塑料內部，內部有常見的冷卻通道。微注射成型機的塑料零件已得到實驗驗證。用模具表面溫度的分布情況和塑料零件的冷卻時間，或是凝固時間相比較分析得到的。結果表明，均勻的溫度分布可減少凝固時間，從而減少塑料零件成型周期。1.介紹注塑成型的方法廣泛使用于塑料部件的工藝生產(chǎn)當中 [1]。注射成型的基本原理是,一個固體聚合物熔化后,注入到模具型腔內，冷卻之后脫模。因此，主要階段是注射成型，過程包括填充、冷卻和脫模。塑模周期決定生產(chǎn)成本效益高低，而冷卻過程是尤為重要的一步。冷卻周期決定部件生產(chǎn)效率。因此，在現(xiàn)代工業(yè)當中，生產(chǎn)成本和生產(chǎn)時間有密切關系，生產(chǎn)部件的時間越久，成本越高。減少冷卻時間可在根本上增加生產(chǎn)效率，并且減少生產(chǎn)成本。因此，理解和優(yōu)化典型的成型過程即內傳熱是很重要的。熱交換率是塑料注射制品和模具的決定性因素，影響注塑模具的生產(chǎn)業(yè)績。A B M Saifullah是工業(yè)研究機構的一名博士生會員, 就讀于斯威本國立科技大學，澳大利亞墨爾本人，電子郵件：msaifullah@swin.edu.au。IAENG. S. H. Masood的是斯威本國立科技大學機械制造工程系的一名教授 , 澳大利亞墨爾本人。聯(lián)系電話:+ 61-3-9214 8260,傳真:+ 61-3-9214 5050,電子郵件:smasood@swin.edu.auIgor Sbarski博士是斯威本國立科技大學機械制造工程系的一名高級講師，澳大利亞墨爾本人。電子郵件:isbarski@swin.edu.au)。熱量必須從塑膠材料上移開，直到達到穩(wěn)定狀態(tài)為止后,才可允許脫膜。此過程中需要完成冷卻時間或是凝固時間。對于最佳熱傳遞過程來說，在熔融的塑料材料和模具間，恰當?shù)睦鋮s系統(tǒng)設計是很有必要的。在模具型芯和型腔內安裝直井眼然后注入冷凍液也就是冰水，使熔融的塑料散熱。此方法用于常規(guī)機械加工過程中，使用直鉆制造這類小孔,而卻不能生產(chǎn)像通道或是3D 空間這類復雜的孔狀。一個冷卻系統(tǒng)的替代方法, 在注射模具的過程當中，符合或適合于模具型腔形狀和核心形狀，才能提供更好的熱傳遞，從而得到最優(yōu)生產(chǎn)周期。這種方法是用不同橫截面相同通道，盡量貼近模具表面減少熔融塑料的熱量。這確保零件均勻冷卻效率更佳。目前，隨著快速成型技術的來臨，例如：直接金屬沉淀工藝，直接金屬激光燒結工藝，還有許多先進的計算機輔助工程軟件的,可以給模具設計并制造許多復雜布局和復雜橫切面的更高效冷卻通道[2、3、4]。本文介紹了一種方形截面的冷卻通道注塑壓模，并模仿這種方法生產(chǎn)一種圓形塑料碗，并與使用模擬仿真分析軟件制作的直線形冷卻通道相比較。用這個方形冷卻通道和傳統(tǒng)的直線形冷卻通道壓模來完成這項驗證性試驗，是為了用微注射成型機制作的模具將一個圓形通道分為兩種塑材。結果表明方形冷卻通道壓模的冷卻時間和溫度分布都比直線形冷卻通道壓模有優(yōu)勢。零件和模具設計方面1. 零件設計用聚丙烯制成的圓形塑料碗，如圖1(a)，采用Pro-Engineer CAD軟件設計的。輸出初始圖形規(guī)格模具表面圖形文檔，在輸入到MPI中進行分析。塑料零件體積是177.90 和質量是162.3mg。試驗測試零件如圖 1(b)，此零件使用Pro-3cmEngineer軟件設計出來的。使用Pro-Engineer CAD軟件對聚丙烯和丙烯腈這兩種類型的塑料材料已做了大量的實驗驗證。測出零件體積是8.8 ,聚丙烯部分和3cm丙烯腈部分質量分別為8.58mg和8.13mg。2 .模具設計模具設計當中利用Pro / Molde 設計Pro / Engineer 系統(tǒng)組件。采用計算機數(shù)控技術制造模具。圖2中所示的模具有兩個部分型心和型腔。采用電腦數(shù)控技術將方形冷卻通道一半設計在型腔部分和另一半設計在型心部分。然后將這兩部分用螺絲連接，并用液態(tài)填料密封以免漏水。圖- 1： CAD 模型（ a）圓形塑料碗， （b）被測試部分。圖- 2 ：CAD 模型的核心（上）和兩個型腔。3．分析結果MPI仿真軟件被用來零件分析[5]。用聚丙烯塑料材料分析注入、冷卻、變形這三步順序。對比分析出方形冷卻系統(tǒng)通道與傳統(tǒng)的直線形冷卻通道的區(qū)別。直線形通道的直徑為12mm，方形通道長度為12mm（圖3）。0.995cm周長的聚變嚙合已被應用到工業(yè)當中。直線形通道和方形通道的嚙合元素的數(shù)量分別為12944個和12291個。這兩種情況下均使用25°標準海水，雷諾數(shù)為10000，熔煉溫度是230℃的冷卻介質。比較分析MPI結果如圖4，從圖中看出，直線形通道溫度分布比方形通道更為均勻些，而方形通道所需冷卻時間相對直線形較少。直線形冷卻通道除了頂頭部分很小以外，大部分零件冷卻時間需要大概24秒，而方形冷卻通道圖解表明其冷卻時間要少于20秒。直線形冷卻通道的凝固時間大概在0.46-93.7秒之間，方形冷卻通道冷卻時間在0.3-87.15秒之間。因此,使用方形冷卻通道，需要5秒的冷卻時間，冷卻時間減少了35%。圖- 3 MPI 分析， （a）：直線型冷卻通道， （ b）：方形冷卻通道圖 4 比較二者冷卻時間， （a ）：方形冷卻通道（b）直線形冷卻通道。4.實驗驗證結果對一個圓形的塑料零件用模具加工機器實驗驗證結果如圖5所示。零件直徑是40mm，厚度是7mm。模具標準尺寸是10x10x2.5 。 模具材料是低碳鋼。3cm用TECHSOFT 迷你模具加工機即一個小型注塑機進行實驗驗證如圖6。兩個采用PICO技術生產(chǎn)的 TC08 K型熱電偶已被用來測量被測試零件的上下表面溫度。聚丙烯和丙烯腈的熔解溫度均是250°C。標準海水已被用來作為冷卻介質,由于室溫25℃,所以叫做冷卻水。冷卻通道直徑是5mm,正方形冷卻通道和直線型冷卻通道標準截面尺寸是5mm。每隔一秒測試一下兩個熱電偶的表面溫度。圖7記錄了丙烯腈- 丁二烯 -苯乙烯塑的方型通道頂部和底部的表面比直線型通道更早冷卻。方形冷卻通道的頂部和底部的表面溫度在特定時間立即注射后最高記錄是52.1和53.36℃，30秒后溫度分別降低到42.47℃和43.07℃,而直線形冷卻通道頂部和底部最高溫度記錄分別是53.24℃和52.01℃,30秒后降到溫度分別為47.72℃和47.47℃。所以，采用方形通道溫度平均可降低4到5℃。用聚丙烯作為零件的材料時實驗也發(fā)現(xiàn)有類似的結果。從圖8可看出使用方形冷卻通道時, 溫度可能降低2 到3℃。實驗測試出20個樣品是由丙烯腈-丁二烯-苯乙烯材料制成的，發(fā)現(xiàn)樣品都具有相同的數(shù)據(jù)。圖9記錄了丙烯腈-丁二烯-苯乙烯樣品試驗和聚丙烯實驗驗證結果圖- 5：（a ）低碳鋼核心（左） （b ）低碳鋼直線形和正方形冷卻通道模具型腔圖 6 測試注塑實驗裝置，左：迷你裝置，右： PC 輸出溫度。圖 7 ABS 溫度比較圖圖- 8：聚丙烯溫度比較圖圖- 9 抽樣檢測，左：ABS 塑料，右：聚丙烯塑料。4.結論注射成型過程轉換到冷卻過程是至關重要的一步,因為冷卻時間通常約占總周期的一半，從而直接影響到模具塑料產(chǎn)品的收縮和彎曲程度。因此,在模具設計當中一個良好的冷卻通道系統(tǒng)是至關重要的,因其影響生產(chǎn)效率和產(chǎn)品質量。MPI仿真結果和實驗驗證表明使用方形冷卻通道可減少35%的冷卻時間，總周期20% 的時間可大大提高注射模零件的生產(chǎn)效率和生產(chǎn)質量。鳴謝這些作者都要感謝來自沃森工業(yè)工程學院的Meredith女士和Phil Watson。他們得到了斯威本國立科技大學的電腦數(shù)控生產(chǎn)模具技術的支持。參考文獻[1] D.V.Rosato, D.V.Rosato和M.G. Rosato，注塑成型手冊第三頁 ,波士頓,英文文獻(2003) 。[2] X. Xu, E. Sach 和S.Allen,注塑模具冷卻通道的適形設計，聚合物工程科學，4, 1, 1269-1272，(2001)。[3] D.E. Dimla, M. Camilotto, and F. Miani:注射成型冷卻通道的工具的設計和優(yōu)化,J. 變形。材料科學論壇,容量: 561-565,聚丙烯。1999-2002, (2007)。[4]一個B 和s . h . Masood M Saifullah、優(yōu)化設計和熱分析冷卻通道的注射模塑料零件模具,材料科學論壇,由561-565 1999 - 2002年,頁。(2007)。[5 A B Saifullah, S. H. Masood和Igor Sbarski，塑料注射成型時使用新型冷卻通道優(yōu)化周期時間和改進零件質量。ANTEC@NPE 2009年,美國。