SPE Library

The SPE Library contains thousands of papers, presentations, journal briefs and recorded webinars from the best minds in the Plastics Industry. Spanning almost two decades, this collection of published research and development work in polymer science and plastics technology is a wealth of knowledge and information for anyone involved in plastics.

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Conference Proceedings
Prediction of Core Shift Effects Using Mold Filling Simulation
Alexander Bakharev, Zhiliang Fan, Franco Costa, Sejin Han, Xiaoshi Jin, Peter Kennedy, May 2004
Uneven distribution of melt flow around a core pin during injection molding can result in core shift. In turn core shift affects the melt flow pattern as it changes the boundary conditions of the flow. Prediction of core shift is important because it causes variations in wall thickness of thin-walled parts.In the article we present algorithms and results of mold filling simulations that take into account the core shift effects.
Visualization and Analytical Simulation of a Viscous Fluid Flow in a Screw Channel
M. Moguedet, J. Balcaen, Y. Béreaux, J.Y. Charmeau, X. Raoul, May 2004
Injected1 long fibre reinforced thermoplastics are widespread in automotive industry, but plastication and fibre breakage occurring are not well-known. We performed original 3D flow visualisation in a transparent screw-barrel unit.Analytical simulations from simplified flow models in screw channels, on metering zone (molten polymer), were used. Particle trajectories obtained by both approaches are compared.
Numerical Simulation of the Filling Stage in the Micro-Injection Molding Process
Florin Ilinca, Jean-François Hétu, Abdessalem Derdouri, May 2004
In this work, a three-dimensional finite element flow analysis code is used to simulate the micro-injection molding problems. Non-Newtonian, non-isothermal flow solutions are obtained by solving the momentum, mass and energy equations. The interface between the polymer and the air is tracked by solving an additional transport equation. Solutions are shown for a mold containing two rectangular cavities, the parts presenting thin ribs of 150?m thickness. The numerical solutions are compared with experimental results.
Increasing Quality by Online Control of the Cavity Pressure
E.h. Walter Michaeli, Juan Gruber, May 2004
An online cavity pressure controller for injection molding has been developed. During the filling phase a constant gradient of the cavity pressure is realized, in the holding pressure phase the cavity pressure is calculated with a pvT-optimization. Controlling the cavity pressure results in higher quality and constant molded part properties.
Ejection of Tubular Polypropylene Mouldings: The Influence of Processing and the Molecular Weight
A.J. Pontes, A.S. Pouzada, May 2004
Polypropylene is used for the production of deep moldings of tubular shape. Predicting the required ejection force is a design issue for this type of moldings.Two polypropylenes of different molecular weights (melt flow indices) were used for producing tubular moldings in an instrumented mould. Experimental data on force and shrinkage was gathered and related for varying processing conditions.
The Effects of Runner Diameter on Packing of a Plastic Part with Injection Molding
Peter C. Knepper, May 2004
This paper presents a study on the effects of runner diameter on packing. Previous studies have focused on gate effects. Injection molding simulations can often indicate that very small runners are adequate for filling, but can freeze off before the part is fully packed out. This study tests various cold runner sizes and materials in order to try and minimize the size of the runner for a given material.
The PVT Effect on Final Sintered MIM Components
Cody D. Greene, Donald F. Heaney, May 2004
Accurately predicting the linear shrinkage of metal injection molded (MIM) components for tool scale-up is commonly done by a combination of estimating shrinkage based on solids loading and prototyping. Extending published techniques from the plastic industry, pressure-volume-temperature (PVT) data and processing parameters are utilized to determine the post molding shrinkage and its effect on final sintered component dimensions. A relationship between injection molding process parameters and sintered component dimensions is presented.
Mechanical Properties of Ultra High Speed Injection Molded Parts
Hiroaki Okumura, Machiko Mizoguchi, Susumu Takashima, Satoko Baba, Shigeyuki Nagata, Hiroyuki Hamada, May 2004
The first attempt of sandwich injection molding with ultra-high speed equipment was described by using Polypropylene as the matrix material. The injection speed of core material was 1000mm/sec. The difference of core progressive behavior between low and high injection speed was recognized. Also the thickness of skin material decreased with increase of core flow length and finally it reached 150?m. The difference of mechanical properties was not significant.
Internal Structure of PC/ABS Injection-Compression Moldings
Hiroyuki Hamada, Kengo Nodo, Susumu Takashima, Satoko Baba, Machiko Mizoguchi, Takashi Kuriyama, Kiyotaka Tomari, May 2004
The internal structures of injection-compression moldings were observed by using PC/ABS blends. Two different filling ratios of injected material were chosen. The internal structure at core had changed from round shape to very fine elongated shape due to additional melt flow during the compression process. This change of structure was strictly dependent on the additional flow. Therefore, in order to make similar internal structure through thickness direction, some amount of flow was needed especially at the core region.
Micromolding Product Manufacture-A Progress Report
Aleksandar K. Angelov, John P. Coulter, May 2004
The scope of this paper is to bring to a wide audience the technology developments in the area of polymer micro/nano molding. Successfully molded products are categorized according to area of their application, and include characteristic dimensions, tolerances, weights, and materials used for each application, except when precluded by confidentiality issues. In this paper, a survey of the accomplishments and research work done in the area of polymer micro/nano molding at several universities and research institutes, and possible new applications for micromolding are presented.
Micromoulding: Process Evaluation
B. Whiteside, M.T. Martyn, P.D. Coates, May 2004
A data acquisition suite capable of monitoring a number of process dynamics at high sampling rates has been installed onto a commercial micromoulding machine. Data was collected during moulding of products of mass 25mg - 0.3mg over a range of process conditions. Results of high shear rate rheology and evaluation of possible material degredation are presented. An investigation into the repeatability of the process has been performed and the paper discusses which process parameter is most suitable as an indicator of moulding conditions which can be used in a process monitoring capacity.
Micro Molding of Polymer Cantilevers for Sensor Applications
J. Zhao, V. Samper, K. Ramesh, G. Chen, J.M.S. Yong, May 2004
In recent years there has been considerable interest in the micro molding process as the trend slanting towards miniaturization. In the present paper micro molding process studies have been carried out on the micro molding of polymer cantilevers for sensor and actuator applications. Microgrinding, EDM, and micro-EDM methods have been used for fabrication of micro cantilever tools. The effects of micro mold surface roughness and process conditions on part quality have also been studied.
Development of a Micro/Nano Injection Molding Testbed
Sung K. Lee, Charles L. Thomas, May 2004
In this work, an injection molding test bed is being developed that is designed specifically for molding micro-scale parts with nano-scale features. The device is designed to mold with sub-milliliter sample sizes and to produce arbitrarily large injection velocities and injection pressures. Initial experiments have produced 125 micron thick, 5000 micron diameter center gated disks with a nanometer scale sinusoidal surface texture. This surface texture will be used to measure shrinkage and warpage on the micro-scale using Micro-Moire.
Assessing Vibration-Assisted Injection Molding through Fatigue Lifetime Studies
Ryan M. Hydro, Raymond A. Pearson, John P. Coulter, David C. Angstadt, Rajesh Gomatam, May 2004
An investigation into fatigue lifetime behavior of polycarbonate and polystyrene materials processed by both conventional and vibration-assisted injection molding (VAIM) is underway. The goal of this investigation is to determine whether the vibration-assisted process improves the fatigue behavior. In addition to characterizing fatigue behavior, the micromechanical deformation mechanicals controlling fatigue behavior will be elucidated.
Counter Flow Injection Molding - An Alternative Method for Producing Parts with Sandwich-Like Morphology
D.B. Tchalamov, J.C. Viana, A.M. Cunha, May 2004
Counter-flow injection molding (CF) is a novel two-component method which can be used for the production of parts with sandwich-like morphology. Compared to some established two-material techniques, CF can induce a higher overall level of molecular orientation and hence an improved mechanical performance. The technique requires a two-component injection molding machine fitted with a special mold. The developed microstructure and mechanical properties of CF moldings are investigated in light of the applied set of processing conditions.
Use of Infrared Thermal Imaging to Study Mold & Part Cooling
John Bozzelli, John Lafeber, May 2004
Infrared thermal imaging has been successfully applied to numerous applications involving electrical, mechanical and building maintenance. Application studies involving plastics have been mostly successful yet our industry does not use Infrared Thermal Imaging. It has not caught on in the plastics industry. This paper presents a series of practical applications involving plastic and mold cooling troubleshooting and analysis. Infrared Thermal Imaging has evolved into a viable method for fast, accurate and economical mold and part cooling studies
Saving Time by Foam Injection Molding
E.h. Walter Michaeli, Sasan Habibi-Naini, May 2004
Foam injection molding (FIM) offers many advantages. One of them is a high potential for cooling time reduction compared to standard injection molding. This paper deals with a thorough investigation on the potential of cooling time reduction by FIM. Results will be presented and discussed in depth.
Designing the Cooling System: What's the Relationship between Mold Material Selection, Water Line Spacing and Mold Surface Temperature Variation
Jay Shoemaker, Kurt Hayden, Paul Engelmann, Patricia Miller, May 2004
Cooling system design is important for making injection-molding tools that have short cycles and produce high quality parts. Guidelines for waterline placement vary widely and don’t satisfy the above requirements. This research used Moldflow to investigate the effects of mold material and waterline spacing on mold temperature variation.
Runner Diameter and Length Effects on Molded-In Stresses of Injection Molded Parts
Scott Robert Cleveland, Joseph Philip Latchaw, May 2004
Molded-in stresses are present in all injection molded parts and can be altered by the melt delivery system of a mold. The length and diameter of runners will have a direct effect on the amount of shear the material is exposed to prior to entering the part cavity and its melt conditions as it flows through the cavity. Various runner diameters and flow lengths are evaluated as to their influence on, and relationship to, the development of residual stresses in a molded part.
Rotofoamability of Polyolefin Resins
Remon Pop-Iliev, Chul B. Park, May 2004
A statistical method was used to analyze experimental data and identify the best-suited polyolefin resins for rotational foam molding operations. The average cell sizes of the skinless foams that occupy the mold to its full volumetric capacity were used as the measured response.

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"Insert title of paper here in quotes,"
ANTEC 2016 - Indianapolis, Indiana, USA May 23-25, 2016. [On-line].
Society of Plastics Engineers
Available: www.4spe.org.

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