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Posts in Category: 'Injection Molding'


The Role of Material Data in the Simulation of Injection Molded Parts

The modeling of material behavior for injection molded plastics is a vital step for good simulation results. We detail the types of material data needed by various injection-molding simulation programs, factors that can affect simulation quality including test techniques and process variables such as moisture content. The case of fiber filled plastics is covered along with the extension to structural analysis applications.

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Plastics Visco-elastic Rate Dependency Injection Molding Nonlinear Material Models Structural Analysis Moldflow LS-DYNA Abaqus Moldex3D DIGIMAT SIGMASOFT Multi-CAE Molding Simpoe-Mold Presentations Validation


Datapoint Newsletter: Summer '17, Volume 23.3

Upcoming Events, Technical Team Expands

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Plastics Injection Molding Structural Analysis Moldflow LS-DYNA ANSYS Moldex3D DIGIMAT Multi-CAE Molding Newsletters Validation ANSA


Workshop: Testing, Modeling and Validation for Plastics & Rubber Simulation in ANSYS

Plastics exhibit non-linear viscoelastic behavior followed by a combination of deviatoric and volumetric plastic deformation until failure. Capturing these phenomena correctly in simulation presents a challenge because of limitations in commonly used material models. We follow an approach where we outline the general behavioral phenomena, then prescribe material models for handling different phases of plastics deformation. Edge cases will then be covered to complete the picture. Topics to be addressed include: Using elasto-plasticity; When to use hyperelasticity; Brittle polymers – filled plastics; Failure modes to consider; Criteria for survival; Choosing materials; Spatial non-isotropy from injection molding; Importance of residual stress; Visco-elastic and creep effects; Strain-rate effects for drop test and crash simulations; Fitting material data to FEA material models; The use of mid-stage validation as a tool to confirm the quality of simulation before use in real-life applications.

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Density Rheology Thermal Mechanical Plastics Rubbers Hyperelastic Visco-elastic Plasticity Rate Dependency Yielding/Failure analysis Injection Molding Structural Analysis ANSYS Presentations Validation


From Manufacturing to Design Validation

[We] introduced the topic of injection molding process simulation and the influence of the manufacturing process on structural analysis. The strength and stiffness of a part can be inaccurately represented if the manufacturing process conditions are not properly considered. This results in a different calculation of system natural frequencies or improper estimation of the energy absorbing characteristics. We continue on this topic, extending the scope to advanced technologies available in the Altair Partner Alliance (APA) to help solve the problem of proper design validation with fiber reinforced plastics.

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Mechanical Aerospace and Defense Automotive Injection Molding Structural Analysis Moldex3D DIGIMAT Papers RADIOSS Newsletters Validation


Thermoplastic Material Testing for Use in SIGMASOFT and the Effect of Moisture on PA 6/6

Thermoplastic materials are one of the largest categories of materials to be injection molded. Moisture-sensitive materials can lead to issues in the molding process. Simulation of the injection molding process requires sophisticated and exact material properties to be measured. This presentation discusses the testing required to characterize a thermoplastic material for use in SIGMASOFT, as well as the effects of moisture on viscosity measurement of a moisture-sensitive material. Consequences of basing designs on wet or dry materials are covered. Implementation of material data into the software to produce a successful injection molding simulation simulation is described.

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Rheology Plastics CAE Vendor/Supplier Injection Molding Nonlinear Material Models SIGMASOFT Presentations


SPE Newsletter - Summer '15

Molding Views, brought to you by the Injection Molding Division of the Society of Plastics Engineers

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Rheology Mechanical Injection Molding Moldflow Moldex3D SIGMASOFT Multi-CAE Molding Simpoe-Mold Newsletters


Mold Tempering: Conformal Cooling - yes or no?

The tempering layout for injection molds is often designed departing from previous experiences. The manufacturing feasibility is the main driver when deciding where to place cooling lines. However, often the relevance of the tempering in the process profitability or in the part quality is underestimated, and due to the lack of better information sometimes the resulting tempering performs far from the optimum. As a consequence, the molding efficiency is reduced, the part quality is compromised and, once the mold is already built, sometimes expensive trial-and-error is required to bring the mold to an optimum configuration.

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Rheology Thermal Plastics Automotive Biomedical Injection Molding SIGMASOFT Newsletters


Ejection system design: Optimization with SIGMASOFT Virtual Molding

As the demand for functional integration and the need of design differentiation in manufactured products increase, the complexity of plastic parts increases as well; thus some previous knowledge on effective ejection systems becomes insufficient and the challenges in the design of ejection systems grow consistently.

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Rheology Plastics Rubbers Visco-elastic Automotive Biomedical Injection Molding SIGMASOFT Newsletters


Cold Runner Design - Getting the whole picture matters

The profitability of a molded rubber product depends to a large extent on the mold efficiency. To achieve the maximum productivity, besides the larges possible number of cavities it is desirable to minimize the rubber consumption and to produce parts without defects.

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Rheology Rubbers Automotive Biomedical Injection Molding SIGMASOFT Newsletters


Estimation of Elongational Viscosity of Polymers for Accurate Prediction of Juncture Losses in Injection Molding

A new elongational viscosity model along with the Carreau-Yasuda model for shear viscosity is used for a finite element simulation of the flow in a capillary rheometer. The entrance pressure loss predicted by the finite element flow simulation is matched with the corresponding experimental data to predict the parameters in the new elongational viscosity model.

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Rheology Plastics Extrusion Injection Molding PolyXtrue Research Papers


Challenges in the Modeling of Plastics in Computer Simulation

Finite-element analysis and injection-molding simulation are two technologies that are seeing widespread use today in the design of plastic components. Limitations exist in our ability to mathematically describe the complexity of polymer behavior to these software packages. Material models commonly used in finite-element analysis were not designed for plastics, making it difficult to correctly describe non-linear behavior and plasticity of these complex materials. Time-based viscoelastic phenomena further complicate analysis. Dealing with fiber fillers brings yet another layer of complexity. It is vital to the plastics engineer to comprehend these gaps in order to make good design decisions. Approaches to understanding and dealing with these challenges, including practical strategies for everyday use, will be discussed.

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Mechanical Plastics Blow Molding Extrusion Injection Molding Nonlinear Material Models Structural Analysis Thermoforming LS-DYNA Abaqus DIGIMAT Presentations


Thermoplastic Material Testing for Use in SIGMASOFT

Thermoplastic materials are one of the largest categories of materials to be injection molded. Simulation of the injection molding process requires sophisticated and exact material properties to be measured. This presentation will discuss the testing required to characterize a material for use in SIGMASOFT, as well as the significance of material model parameters. Differences in testing methodology for amorphous and semi-crystalline polymers will be covered, along with step-by-step implementation into the software to produce a successful injection molding simulation simulation.

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Plastics Electonics/Electrical Injection Molding Nonlinear Material Models Structural Analysis SIGMASOFT Presentations


Software for Creating LS-DYNA Material Model Parameters from Test Data 

LS-DYNA software contains a wealth of material models that allow for the simulation of transient phenomena. The Matereality® CAE Modeler is a generalized pre-processor software used to convert material property data into material parameters for different material models used in CAE. In a continuation of previously presented work, we discuss the extension of the CAE Modeler software to commonly used material models beyond MAT_024. Software enhancements include advanced point picking to perform extrapolations beyond the tested data, as well as the ability to fine-tune the material models while scrutinizing the trends shown in the underlying raw data. Advanced modeling features include the ability to tune the rate dependency as well as the initial response. Additional material models that are quite complex and difficult to calibrate are supported, including those for hyperelastic and viscoelastic behavior. As before, the written material cards are directly readable into the LS-DYNA software, but now they can also be stored and catalogued in a material card library for later reuse.

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Plastics Rubbers Foams Metals High Speed Testing Injection Molding Nonlinear Material Models Structural Analysis LS-DYNA Composites Presentations


Datapoint Newsletter: Late Spring '14, Volume 20.2a

Verification and Validation Are Focus of Technical Presentations at CAE Events, New Multi-CAE TestPaks® Deliver Data for Injection Molding and Crash Simulations,

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High Speed Testing Injection Molding Newsletters


Comments on the Testing and Management of Plastics Material Data 

Plastics appeared as design materials of choice about 30 years ago. They brought with them huge design challenges because their multi-variable, non-linear nature was not well understood by engineers trained to work in a linear elastic world. We outline a 20 year journey accompanying our customers in their efforts to understand and simulate these remarkable materials to produce the highly reliable plastic products of today. We discuss challenges related to processes such as injection molding vs. blow-molding; coping with filled plastics; the difficulties of modeling polymers for crash applications. We include our latest findings related to volumetric yield in polymers and its relationship to failure. We describe the material database technology that was created to store this kind of multi-variable data and the analytical tools created to help the CAE engineer understand and use plastics material data.

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Plastics Automotive Blow Molding High Speed Testing Injection Molding Nonlinear Material Models Structural Analysis Moldflow LS-DYNA Abaqus ANSYS Moldex3D DIGIMAT Multi-CAE Crash Multi-CAE Molding Multi-CAE Structural PAM-CRASH Presentations


A Standardized Methodology for the DigimatMX Reverse Engineering Process 

We present a methodology for DIGIMAT users to perform the DIGIMAT MX reverse engineering process to obtain material parameter inputs for crash, elasto-plastic, creep and visco-elasticity. The injection-molding process used involves a standardized plaque geometry with fully developed flow, with test specimens taken from a specific plaque location. A standardized testing procedure is applied and the resulting DIGIMAT MX inputs are handled in a streamlined data stream, which saves time and improves the reliability of the reverse engineering process. The DIGIMAT MX reverse engineering itself can be performed as a service in collaboration with e-Xstream. This gives the user a speedy and tightly controlled process for performing complex finite element analysis with filled plastics

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Blow Molding Extrusion High Speed Testing Injection Molding Nonlinear Material Models Structural Analysis DIGIMAT Presentations


Mechanical and Visco-Elastic Properties of UHMWPE for In-Vivo Applications 

Ultra-high molecular weight polyethylene (UHMWPE) is used extensively in orthopedic applications within the human body. Components made from these materials are subject to complex loading over extended periods of time. Modeling of components used in such applications depends heavily on having material data under in-vivo conditions. We present mechanical and visco-elastic properties measured in saline at 37C. Comparisons to conventionally measured properties at room temperature are made.

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Plastics Biomedical Blow Molding Extrusion Injection Molding Nonlinear Material Models Structural Analysis Moldflow Abaqus ANSYS SIGMASOFT Papers POLYFLOW Blow Molding POLYFLOW Extrusion POLYFLOW Thermoforming


Material Modeling and Mold Analysis 

We present a perspective on material modeling as applied to mold analysis requirements. Melt-solid transitions and the case for a unified material model are discussed, along with prediction of post-filling material behavior and shrinkage, and the impact of viscous heating on flow behavior and material degradation.

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Plastics Rubbers Foams Metals Aerospace and Defense Automotive Biomedical Consumer Products Energy and Petroleum Electonics/Electrical Industrial Goods CAE Vendor/Supplier Packaging Home Appliances Blow Molding Extrusion Injection Molding Nonlinear Material Models Moldflow Composites Presentations Gels Oils/Lubricants Waxes


Successful Injection Molding: Book Review

There has been a long standing need for a book that describes the process of injection molding using the insights developed from twenty years of computer aided engineering (CAE). The authors, all veterans of injection molding CAE, have filled this need with their book. "Successful Injection Molding" is a lot more than a book about injection molding CAE. It is clear at this stage that CAE is a tool, which, if well handled, can provide excellent results. That being said, a successful implementer of CAE for injection molding must have a range of insights into the diverse idiosyncrasies of this enormously complex manufacturing process. The book is successful in clearly addressing these issues.

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Injection Molding Book Review


Closing the Gap: Improving Solution Accuracy with Better Material Models 

We discuss open issues in material models for plastics and propose better means of acquiring the right material data for Moldflow simulations using current testing technologies.

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Plastics Material Supplier Mold Maker/Designer Injection Molding Moldflow Presentations


Material Models in Simulation, Part 3: New viscosity models 

We discuss developments in viscosity modeling. New models are not generalized, but are designed to predict expected trends for polymers and incorporate both Newtonian and shear-thinning behavior.

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Plastics Material Supplier Mold Maker/Designer Injection Molding Moldflow Presentations


Understanding the Role of Material Properties in Simulations, Part 2

We discuss material properties in injection molding simulations, including the definition of property requirements, identification of evaluation parameters, and the role of material properties at each stage of the injection molding process, from mold filling through cooling, post-filling and shrinkage/warpage considerations.

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Plastics Material Supplier Mold Maker/Designer Packaging Injection Molding Moldflow Moldex3D Cadmould C-MOLD Presentations


Injection Molding Handbook: Book Review

This book, edited by the Wisconsin based team of Osswald, Turng and Gramman, represents a compilation of work by several well known authors and brings together a body of knowledge that will be appreciated by injection molding professionals and students of plastics processing.

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Plastics Injection Molding Book Review