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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Tensile Properties of PE Clay Nanocomposites via Taguchi Based Design of Experiments
LDPE and HDPE clay nanocomposites prepared with melt mixing demonstrate increased stiffness and strength with increasing concentrations of clay nanocomposites and adhesion promoters. Taguchi design of experiment (DOE) methodology determined the optimum material conditions to achieve maximum strength and stiffness. The nanocomposites increased tensile modulus and tensile strength, but reduced elongation of LDPE and HDPE. Maleic anhydride and acrylic acid improved the tangent modulus and ultimate tensile strength of polyethylene/clay nanocomposites.
Terpolymer Sequences and Geometric Distribution
Chain sequence distribution calculations for terpolymers using probability model and Monte Carlo simulation methods are discussed. The SSS, AAA, SAS, SSA, ASA, AAS trial concentration are obtained. Molecular weight and ceiling temperature effects are studied using the Monte Carlo method.
Three-Dimensional Filling and Post-Filling Simulation of Metal Injection Molding
A 3D finite element code including free-surface flow is used to simulate metal injection molding (MIM) of a stainless steel compound with an aqueous gel binder. The thermal analysis couples the highly conductive MIM compound with the mold wall. Predictions are compared with pressure and melt temperature data for filling and packing a long thin plate over a wide range of operating conditions. The purpose of this work is to advance MIM technology, as has been done in the plastics industry, by interactive use of experiment and simulation.
Three-Dimensional Simulation of Thermoset Molding Applied to Semiconductor-Chip Encapsulation
In this paper, numerical methods to analyze the flow of thermoset materials during the molding process have been developed. A finite-element method is used for the three-dimensional flow analysis. The numerical analysis results have been verified by comparing with experiments. In the experiment, a semiconductor chip encapsulation process using a thermoset-molding compound has been used to observe the melt-front advancement shapes. The calculated and experimental results show good agreement.
Time-Resolved SAXS Studies on the Crystallization Behaviors of Poly(Ethylene Terephthalate) and its Copolymers
Using synchrotron radiation sources of Pohang Light Source, Pohang University of Science & Technology, Korea, small-angle X-ray scattering (SAXS) measurements have been carried out for poly(ethylene terephthalate) (PET) and poly(ethylene isophthalate-co-terephthalate) s which undergo isothermal crystallization and during subsequent re-melting. Differential scanning calorimetric (DSC) measurements were additionally conducted.
Transient Behavior of Extruders: Input Disturbances
A model of the transient response of an extruder to varying input feed rates and screw speed was developed and used to study the effect of input disturbances on the extrusion process. Simulated tests reveal that given a screw design, there is a critical frequency below which disturbances will not be damped significantly by the extruder. The relationship between screw geometry and this critical frequency is presented. The effect of specific throughput (Q/N) on damping ability of a screw geometry is also presented in this paper.
Transient Simulation of Film Blowing Process
Analysis of film blowing process using a transient, axisymmetric, non-isothermal, viscoelastic model is presented in this paper. The model developed is solved using the finite element method. Constitutive behavior of the polymer is described using a combination of modified Phan-Thien-Tanner model and anisotropic Kelvin-Voight model. A simple crystallinity model is used to describe the phase change and crystallization kinetics. Steady state solutions predicted by the model are compared with experimental results, these results along with transient results are presented in this paper.
Troubleshooting Dehumidifying Dryers
Engineering materials - such as nylon polycarbonate and the like - have a molecular attraction for moisture and are hygroscopic polymers. When exposed to a humid atmosphere these materials take up and retain water. However this process can be reversed if the pellets are exposed to an artificial environment where the air temperature and dewpoint is precisely controlled for a pre-determined length of time. A good understanding of four fundamental drying parameters along with the basic principles of operation of a dehumidifying dryer are essential to troubleshooting a drying system."
Ultrasonic Application Solutions Using the Latest Advances in Equipment Technology
Ultrasonic welding is used in many applications. The benefits of the welding process include: elimination of consumables, fast cycle times, compact machine footprint, and relatively low cost capital investment. New advances in ultrasonic products and technology make this method possible for applications not previously suitable for ultrasonics. Today’s equipment can program and profile weld and hold force as well as amplitude during the weld cycle. Also, new frequencies have been introduced which expand the capabilities of horns and energy transmission.
Understanding and Developing Human Capital
The focus of this paper is to probe the aspect of Human Capital in today's growing companies. Human Capital is the sum of the intangible pieces of a company outside of its physical assets. Human Capital is more than human resources, more than training. Human Capital and the way it's used defines the success of a company. This paper will uncover how to understand and how to develop it in our companies. Case studies will give the benefits of developing the greatest asset we have in Human Capital.
The Use of a Design of Experiments (DOE) to Optimize Processing Conditions of an Injection Molded Gear
A Design of Experiments (DOE) was performed to optimize processing conditions of an acetal copolymer injection molded gear. Nineteen experiments were performed using five independent variables. The independent variables were melt and mold temperature, injection speed, hold pressure, and hold time. Dependent variables (outputs) included weight, dimensions, total composite error (TCE), tooth-to-tooth error (TTE), and tooth break strength. The results of the DOE indicate there are molding parameters that will meet the dimensional and functional requirements.
The Use of Color Tolerancing Schemes to Accurately Analyze and Control Color in the Plastics Industry
The consumer judges the quality of all products, including plastics, in part by the color and appearance of those products. One issue involved is the determination of the target color for a product. This is essentially an issue of agreement between customer and vendor. Possibly more important, is the determination of an acceptable tolerance. What is deemed acceptable color, and what is unacceptable. What tolerance scheme should we use, and how do we determine what is an acceptable limit? This paper has been written to explore these important issues.
The Use of Nanometer Sized Glass as a Filler for Polyvinylidene Floride (PVDF)
This project is structured around the idea that Polyvinylidene Floride (PVDF) is an expensive engineering grade resin. This research will attempt to use nanometer sized glass filler with the virgin material at the correct loading to attain the desired properties and become more cost effective. The glass filler will compliment the chemical resistance of the PVDF which is one of its most desired properties, as well as, increase the flame retardance of the manufactured product.
Usefulness of Numerical Injection Molding Simulation Results for Prediction of Mechanical Behavior of Plastics Components
Several companies and institutions contributed to a project for which thick-walled gas tube connectors were injection molded of high-density polyethylenes applying different molding parameter combinations. Connectors were mechanically tested, and numerical simulations of injection molding were carried out. With a simple ranking method it was possible to show correlations between performance under internal pressurization and predictions of shear rates, shear stresses, and thermal shrinkage differences between different locations.
Using Castings for Molds for Competitive Advantage.
Rapid tooling, prototype or production, molds and mold inserts cast net shape into ceramic molds can give you an edge over competition.Decorative tooling, impossible to machine or EDM molds with intricate features such as horse replicas.Near net shape, mold inserts with minimal finish stock on the cavity shape and partings in a sand or ceramic casting process. Casting in all parting line relieves, saving rough machining, time, process steps and money.Conformal cooling, mold inserts with cast in waterlines conforming to the shape of the cavity, allow faster cycle times, reducing mold weight, material costs and press wear.
Using Large Area Automated Microscopy to Characterize Fiber-Reinforced Composites
Establishing a quantitative linkage between materials, method of fabrication, and the final properties and on-site performance of a manufactured component is a key requirement for the further usage of composite materials in critical applications. Detailed and large-scale topological characterization is an essential first step in this direction. Here we show how Large Area Automated Microscopy (LAAM) can be used to characterize fiber-reinforced composites by detecting (1) fiber misalignment and (2) porosity.
Viscoelasticity of New Molecularly Designed Polypropylenes
The linear viscoelastic properties of a series of new molecularly designed polypropylenes were studied. The high melt strengths of these gel-free materials make them suitable for a wide range of applications. The results of dynamic measurements were combined with creep compliances to provide broad experimental windows. The impact of changing molecular structure on the relaxation spectrum is elucidated and compared with that metallocene polyethylene.
Warpage Prediction of Latch Housing
With the increasing demand for weight reduction in vehicles, the electronic devices are becoming more compacted, and the plastic fixtures for the electrical components are becoming more complicated. In this paper, the warpage of a plastic latch housing is investigated using Moldflow Plastics Insight (MPI). Inside this housing, several copper traces are embedded. Proper boundary conditions are applied within MPI and the predicted warpage matches well with the prototype results.
Wear Mechanisms in Plasticating Units - A Literature Survey -
This literature survey focuses on the phenomena of wear that occur in screw-barrel systems. Some studies have shown that various types of wear occur in the individual zones of the screw depending on the materials processed and process parameters. Abrasion, corrosion and adhesion are the factors that limit the service life of the processing machines, especially as the overlapping of several mechanisms, that occurs sometimes, lead to accelerated wear.
A Web Based Stretch Blow Moulding Simulation
A simulation of the injection stretch blow moulding process has been developed. However an in-depth knowledge of Finite Element Modelling is required to enable it to be used. The object of this work was to provide a user-friendly Web-based interface that would enable engineers without Finite Element experience to investigate preform and bottle designs. A form is provided for the user to submit the required blow moulding parameters. Once the simulation has been completed a contour plot of the thickness distribution of the formed bottle and an animation of the simulation are made available on the web server.
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