1.15 Micro Plastic Part Filling Capabilities through Simulation and Experiment: A Case Study on Micro Gear Shape

Micro plastic molding is a new niche area in injection molding industry and growing faster due to its huge application in various sectors. This reflects the increased interest from researchers to produce high precision micro plastic parts. The challenge in micro molding is on part design, tooling, molding machine, part inspection, and plastic materials. The present study starts with the design and fabrication of injection molding machine that is suitable for micro molding application, with the provision of a window for flow behavior observation. The works continue with exploring the flow behavior in various shapes and sizes of micro channel. A modified cross viscosity model has been formulated to identify the filling capability of straight, reverse ‘T’ and cross ‘+’ shape micro channel with various sizes. The results obtained from Moldflow simulation, ANSYS CFX, and actual experiments at different mold and melt temperatures are compared. ANSYS CFX gave similar results with that of experiments by modification of the cross viscosity model. In conclusion, this study proposes a modified ‘cross viscosity model’ to be used in ANSYS CFX simulation package which is capable of analyzing a specific micro part in micro injection molding.

[1]  Douglas E. Smith,et al.  Analysis and sensitivity analysis for polymer injection and compression molding , 1998 .

[2]  T. Jaaskelainen,et al.  Replication of sub‐micron features using amorphous thermoplastics , 2002 .

[3]  Sheng-Jye Hwang,et al.  Control of Hot Runner Type Micro Injection Molding Module , 2007, IECON 2007 - 33rd Annual Conference of the IEEE Industrial Electronics Society.

[4]  Cheng Yang,et al.  Three Dimensional Flow Analysis During Injection Molding Process For Stacked-Die Packages , 2007, 2007 32nd IEEE/CPMT International Electronic Manufacturing Technology Symposium.

[5]  Ming-Shyan Huang,et al.  Simulation of injection-compression mold-filling process , 1998 .

[6]  Yung Kang Shen,et al.  EXTENSION METHOD AND NUMERICAL SIMULATION OF MICRO-INJECTION MOLDING , 2004 .

[7]  Wen-Bin Young,et al.  Simulation of the filling process in molding components with micro channels , 2005 .

[8]  W. Michaeli,et al.  New plastification concepts for micro injection moulding , 2002 .

[9]  Hidetoshi Yokoi,et al.  Visual analysis of the flow behavior of core material in a fork portion of plastic sandwich injection molding , 2003 .

[10]  Shih-Jung Liu,et al.  Dynamic visualization of cavity-filling process in fluid-assisted injection molding-gas versus water , 2007 .

[11]  C. K. Huang,et al.  Polymeric nanofeatures of 100 nm using injection moulding for replication , 2007 .

[12]  Wen-Hsien Yang,et al.  Numerical simulation of mold filling in injection molding using a three‐dimensional finite volume approach , 2001 .

[13]  C. K. Huang.  Filling and wear behaviors of micro-molded parts made with nanomaterials , 2006 .

[14]  S. Chen,et al.  Study on rheological behavior of polymer melt flowing through micro-channels considering the wall-slip effect , 2005 .

[15]  Hidetoshi Yokoi,et al.  Process along thickness direction , 2000 .

[16]  Jatan P. Shah,et al.  Implementation and analysis of polymeric microstructure replication by micro injection molding , 2004 .

[17]  W. Michaeli,et al.  A NEW INJECTION MOLDING TECHNOLOGY FOR MICRO PARTS , 2001 .

[18]  Ming Huang,et al.  Nonlinear Fitting Technology of 7-Parameter Cross-WLF Viscosity Model , 2011 .

[19]  Marc Madou,et al.  Experimental investigation and numerical simulation of injection molding with micro-features , 2002 .

[20]  S. F. Shen,et al.  A finite-element/finite-difference simulation of the injection-molding filling process , 1980 .

[21]  Yung Kang Shen,et al.  AN ANALYSIS OF THE THREE-DIMENSIONAL MICRO-INJECTION MOLDING , 2002 .

[22]  Yung Kang Shen,et al.  THREE-DIMENSIONAL NON-NEWTONIAN COMPUTATIONS OF MICRO-INJECTION MOLDING WITH THE FINITE ELEMENT METHOD , 2002 .

[23]  E. Bociąga,et al.  Experimental investigation of polymer flow in injection mould , 2007 .

[24]  Kim Tiow Ooi,et al.  Study on the viscosity of the liquid flowing in microgeometry , 1999 .

[25]  A.C.-Y. Wong,et al.  Study on the melt entry flow characteristics in axisymmetric dies with abrupt contraction by a visualization technique , 2001 .

[26]  I. Sun,et al.  Flow Visualization of Filling Process during Micro-Injection Molding , 2002 .

[27]  Michael Sylvester Packianather,et al.  Micro-injection moulding: Factors affecting the achievable aspect ratios , 2007 .

[28]  J. Zhao,et al.  Polymer micromould design and micromoulding process , 2003 .

[29]  D. Kwiatkowski,et al.  Investigations of the plastics flow during the injection molding process - selected results , 2006 .

[30]  Fabrizio Quadrini,et al.  Direct molding of thermoplastic micro-parts , 2008 .

[31]  Xuehong Lu,et al.  A statistical experimental study of the injection molding of optical lenses , 2001 .

[32]  Jonathan A. Dantzig,et al.  Modeling in Materials Processing , 2001 .

[33]  Kathleen Feigl,et al.  Development and evaluation of a micro-macro algorithm for the simulation of polymer flow , 2006, J. Comput. Phys..

[34]  J. Giboz,et al.  Microinjection molding of thermoplastic polymers: a review , 2007 .

[35]  Optimum cooling system design of a free-form injection mold using an abductive network , 2002 .

[36]  S. Dimov,et al.  The effects of tool surface quality in micro-injection moulding , 2007 .

[37]  Wen-Bin Young,et al.  Analysis of filling distance in cylindrical microfeatures for microinjection molding , 2007 .

[38]  R. Spares,et al.  Micromoulding: extreme process monitoring and inline product assessment , 2005 .

[39]  S. Dimov,et al.  Investigation of micro-injection moulding: Factors affecting the replication quality , 2007 .

[40]  Ahmet Özdemir,et al.  Flow front advancement of molten thermoplastic materials during filling stage of a mold cavity , 2004 .

[41]  W. Young,et al.  Analysis of the filling capability to the microstructures in micro-injection molding , 2009 .

[42]  M. Kuittinen,et al.  Transparent thermoplastics: Replication of diffractive optical elements using micro-injection molding , 2007 .

[43]  Kanzo Okada,et al.  A lubrication theory for fluids with microstructure , 1995 .

[44]  Sheng-Jye Hwang,et al.  Development of an external-type microinjection molding module for thermoplastic polymer , 2007 .

[45]  Jean-Claude Gelin,et al.  Direct observation of mould cavity filling in ceramic injection moulding , 2008 .

[46]  Yasuo Kurosaki,et al.  A new concept of active temperature control for an injection molding process using infrared radiation heating , 2002 .

[47]  Jianhong Zhao,et al.  Effects of process parameters on the micro molding process , 2003 .

[48]  J. Koszkul,et al.  Viscosity models in simulation of the filling stage of the injection molding process , 2004 .

[49]  M. T. Martyn,et al.  In-process Monitoring of Micromoulding – Assessment of Process Variation , 2005 .

[50]  S. Hatzikiriakos,et al.  Wall slip in the capillary flow of molten polymers subject to viscous heating , 1997 .

[51]  Yung Kang Shen,et al.  Analysis for microstructure of microlens arrays on micro-injection molding by numerical simulation , 2008 .

[52]  H Yokoi,et al.  Visualization analysis of flow front behavior during filling process of injection mold cavity by two-axis tracking system , 2002 .

[53]  J. Collier,et al.  Injection molding of polymeric LIGA HARMs , 1999 .

[54]  Byung Kim,et al.  INCREASING FLOW LENGTH IN THIN WALL INJECTION MOLDING USING A RAPIDLY HEATED MOLD , 2002 .

[55]  Kevin W. Kelly,et al.  Injection molding using high-aspect-ratio microstructure mold inserts produced by LIGA technique , 1998, Photonics West - Micro and Nano Fabricated Electromechanical and Optical Components.

[56]  Nitin R. Anturkar.  Petrov-Galerkin finite element analysis for advancing flow front in reaction injection molding , 1995 .

[57]  K. Kelly,et al.  Design and fabrication of a cross flow micro heat exchanger , 2000, Journal of Microelectromechanical Systems.

[58]  Liyong Yu,et al.  Flow and heat transfer simulation of injection molding with microstructures , 2004 .

[59]  Byung Kim,et al.  Scaling Issues in Miniaturization of Injection Molded Parts , 2004 .