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
3D Numerical Simulation of Flip-Chip Underfill Encapsulation
Yung-Yuan Wang, Chi Chung Hsu, Rong-Yeu Chang, May 2005
The analysis of encapsulant flow during under-fill encapsulation would be discussed in this work. With solving the melt-front positions based on 3D Finite Volume Method, we get better predictions than 2.5D simulation. For the surface effects among encapsulant, bumps and substrate, the results illustrate that the variations of contact angle influence filling time greatly. Moreover, by applying approximated parameters of dynamic contact angle model, we can simulate the influence of different processing conditions on filling time predictions.
Molding of Polycarbonate / ABS Parts for Chrome Electroplating
John A. O’Meara, May 2005
Electroplating PC/ABS requires the plastic be conditioned through “etching” where metal is interlocked into the part. This only occurs when the part has a butadiene-rich surface. Not achieving this condition results in costly unrecoverable plated scrap. In this study, the injection molding process effect on plating scrap was studied where it was learned that the slower the injection rate provides less plating scrap, contrary to traditional molding efficiency.
Slender Bubbles: Inertial Effects and Stability
Moshe Favelukis, Olga M. Lavrenteva, Avinoam Nir, May 2005
The influence of inertia on the deformation and breakup of a slender bubble embedded in a Newtonian liquid in an axisymmetric extensional flow has been theoretically studied. The steady-state problem is governed by two dimensionless parameters: The capillary number and the Reynolds number for the external flow. The calculated stationary deformation reveals the existence of multiple solutions. A stability analysis of these results is used to distinguish between stable and unstable solutions and to establish the break-up point.
Effect of Process Aids on Interfacial Instabilities in Coextrusion
M. Zatloukal, J. De Witte, May 2005
New slip model based on ‘effective continuum methods’ for the description of slip was developed and used for investigation of process aids effect on the zigzag type of interfacial instabilities in coextrusion flow.
Design of PVC Pipes for Shock Resistance
Anne-Sophie Lichtlé, Laurence Meylheuc, Dmitry Kucharavy, Emmanuel Caillaud, May 2005
One of the major difficulty in designing extruded structures consists in understanding and managing their driving parameters like: material structure;process characteristics;their system effects; which influence the shock resistance. Thus, it is proposed to identify these relationships within the context of redesigning the PVC pipes for sewer systems.
Carbon Assisted Laser Sintering of Thermoplastic Polymers
N. Woicke, T. Wagner, P. Eyerer, May 2005
Selective laser sintering (SLS) with CO2 lasers is only used commercially with polyamide (PA) and polystyrene (PS). This is because only these polymers absorb enough energy to melt properly in the SLS process.In a new approach, carbon black is added to the thermoplastic polymer powder. Carbon is sensitive to the wave length of Nd:YAG lasers and can absorb enough energy that adjacent polymer melts.In this paper a feasibility study of this new method is presented. As an example the sintering behaviour of the high temperature resistant polymer polyether ketone (PEK) is shown.
Evaluating Flow through Grill-Like Features Using Width-To-Thickness Ratio in an Adjustable Mold
Nicholas McGrady, Nathan Sumy, May 2005
Using a mold specifically designed for the purpose of studying Width-to-Thickness Ratios in grill shaped geometry, parts are molded at each of four different width-to- thickness ratio settings using a control ratio of 10:1 in each setting. Semi-crystalline and amorphous behavior is investigated.
Experimental and Numerical Investigation of the Elongational Viscosity Effects in a Coat-Hanger Die
Y. Sun, M. Gupta, J. Dooley, K.A. Koppi, M.A. Spalding, May 2005
The flow in a flat die is simulated using the axisymmetric and planar elongational viscosities of a low-density polyethylene (LDPE) resin. Elongational viscosity is found to have only a limited effect on the velocity distribution at the die exit. However, the predicted pressure drop in the die increased when the effect of elongational viscosity is included in the simulation. Predicted pressure drop is compared with the corresponding experimental data.
Comparative Performance and Barrier Properties of Biodegradable Thermoplastics and Nanobiocomposites vs. PET for Food Packaging Applications
D. Cava, A. López- Rubio, L. Cabedo, E. Giménez, J.L. Feijoo, R. Gavara, J.M. Lagaron, May 2005
This paper reports about the comparative behaviour, regarding PET, of biodegradable biopolymers such as PCL, PLA and PHBcoV and their nanobiocomposites, in terms of thermal and retorting resistance (thermal humid processes) and oxygen, water vapour and aroma barrier by means of time-resolved synchrotron radiation, FT-IR and permeation methods.
Drawing Forces and Film Properties in Semi Sequentially Stretched Polypropylene
Michael A. McLeod, May 2005
The relationship between biaxial stretching kinematics and oriented polypropylene film properties was studied. Initially only transverse direction (TD) speed was varied while areal draw ratio and machine direction (MD) speed were held constant. Slow TD speeds increased final TD drawing force and produced anisotropic film shrinkage. Tensile properties were primarily a function of draw ratios. Using different MD and TD draws allowed tensile properties to be changed while holding film shrinkage nearly constant.
Melt Fracture Analysis Using an In-Line Camera
Michael A. McLeod, May 2005
A low melt flow rate metallocene isotactic polypropylene homopolymer was cast into film with and without melt fracture. Using an in-line camera, melt fracture was quantitatively described using real-time measurements of film defects. Melt fracture caused more variation in light transmittance, leading to a higher defect count. This measure of film optics was more sensitive to melt fracture than haze or gloss.
Scratching Behaviors in Injection Molded Products
Machiko Mizoguchi, Takashi Kuriyama, Hiromi Kita, May 2005
Scratch behaviors of injection molded products, such as PS, HIPS, ABS, PC/ABS, were investigated. From the observation by optical microscopy of scratch, the damages generated were understood. They depended on the types of polymers and the structure near the surface generated during the injection molding. The scratch behaviors would be affected by friction between the polymers and scratch tip and modulus, yield strength, fracture toughness of the polymers.
Fast Simulation Methodology and its Application in Injection Molding
Shen Changyu, Yu Xiaorong, Li Qian, May 2005
The injection molding is a popular technique of polymer processing, which multiple parts with tight tolerances and complex shape can be produced in a single operation. Through studying the flow behavior of melt in cavity and runner system, a fast flow simulation method is developed based on the introduction of the equivalent flow length concept. The optimization algorithms and fast flow simulation technology are integrated to optimize gate design.
Morphology of PC/ABS Blend Systems Fabricated by Injection Moldings
Machiko Mizoguchi, Takashi Kuriyama, May 2005
Morphology of PC/ABS injection moldings was observed by TEM in parallel to flow direction and transverse. The thin films, which thickness was less than 100 m, of PC and ABS were observed near the surface with regardless of injection speed, while ABS was in fibrous shape at the center. The geometry of butadiene rubber domains creating salami occluding SAN was a focus. It is confirmed that they elongated in flow directions.
An Approach to Gradation Mesh Generation in Injection Molding Simulation
Xiao-Dong Yang, Chang-Yu Shen, Chun-Tai Liu, Jing-Bo Chen, May 2005
Based on advancing-front method and Delaunay triangulation concept, a new interior point generation scheme is proposed. The longest edge at the current advancing-front is always chosen to create a new triangle element by using Delaunay triangle’s property, so that a high-quality graded mesh is obtained and a smooth transition in element size is maintained. The high-quality mesh can make plastics injection molding computer simulation more precise.
Influence of Clay Orientation and Aspect Ratio on Morphology and Mechanical Properties of Nylon-6/Clay Nanocomposites
J.-I. Weon, H.-J. Sue, May 2005
The influence of clay orientation and aspect ratio on morphology and mechanical properties of nylon-6/clay nanocomposites is investigated. Our findings suggest that clay orientation can affect the nucleation and orientation of crystalline lamellae of nylon 6 matrix. The presence of clay also hinders the relaxation of nylon matrix during annealing. Consequently, clay aspect ratio and orientation can greatly influence the overall morphology and mechanical properties of the nanocomposite.
Novel Dynamic Nucleation Theory for Microcellular Plastics
ZHOU Nan-qiao, ZHU Wen-li, PENG Xiang-fang, ZHANG Zhi-hong, May 2005
Polystyrene microcellular plastics blown with supercritical carbon dioxide were prepared by novel electromagnetic dynamic foaming simulator. Bubble nucleation processes in stable and dynamic shearing flow field were analyzed. The experiments showed that after imposing vibration, cell size decreased and cell density increased. The key issue with dynamic nucleation is that the shear energy generated by mechanical vibration improved bubble nucleation. Novel dynamic nucleation theory was put forward from the viewpoint of shear energy in this paper.
The Effects of Runner Diameter and Cavity Size on Packing a Part in Injection Molding
Christopher Welsh, Christopher Stewart, May 2005
This paper presents the study which challenges some of the classic theory regarding runner sizes as related to packing. This study has found that, in some cases, packing control can be maintained with runner diameters which may be as small as, or even smaller than, the wall thickness of the parts being molded. This study further showed that in some cases, increasing cavity size allowed for improvements in packing control. Both of these findings are contrary to the classical wisdom used for today’s runner designs.
Performance of a Machine Augmented Composite
J. Kim, T.S. Creasy, G.F. Hawkins, M.J. O’Brien, May 2005
An advanced machine augmented composite was fabricated and tested. This composite is composed of rigid polyurethane machines with pre-buckled walls as a reinforcement and soft polyurethane as a matrix. Dynamic properties of the composite were measured in the frequency of 0.1 ~100 Hz range at room temperature by load-controlled cyclic testing. Measured tan ? values and loss modulus showed noticeably higher values than the matrix did at the frequency range of 0.1~ 40 Hz.
The Criss-Cross Die
Stephen J. Derezinski, May 2005
The typical center-fed manifold-die has a pressure at the center higher than at the edges that gives rise to an uneven flow distribution. This is eliminated by the crisscross die, which has two end-fed manifolds with half-flows in opposing directions. One half-flow has a pressure gradient equal and opposite to that of the other. The two opposed half flows and pressure gradients combine in a main delivery manifold to create a uniform pressure across the width of the die. The result is a die that produces extremely uniform widthwise flow for use in sheet manufacture and coatings.
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