In this study, we propose an integrated particle approach based on the coupling of smoothed particle hydrodynamics (SPH) and discrete element method (DEM) to predict the injection molding process of discrete short fibers. The fibers in the coupled SPH-DEM model are treated as non-rigid bodies to allow deformation and fracture. The interaction between resin and fibers is solved by a physical model to take into consideration of drag forces. Two cases of injection molding process with different volume fractions of short fibers are studied to predict the flow behaviors of fibers and resin. The numerical results qualitatively agree with previous experimental studies. It is found that the velocity contour of resin flow is parabolic in shape due to the velocity gradient near the wall boundaries and consequently the moving direction of fibers is in parallel with the flow direction of resin. Fiber accumulation is found in the case with higher content of short fibers.
mold flow simulation pdf 20
There are two main applications for mold-filling simulation. One is in optimizing a new mold design before steel is cut. The second is solving problems with an existing mold. Both can save lots of time and money.
1. Make a list of what is expected of the analysis and decide if the benefits justify the cost. Do you want iterations at different fill times, temperatures, and gate locations? Do you want to know the clamp-pressure requirement? (Note: When a mold has slides, flow simulation generally does not predict the forces projected against the clamp over the heel blocks.) Want to make sure you know weld-line locations, high-stress areas, venting issues, or pressure distribution? Do you need to make sure your equipment has the shot size and injection speed/pressure necessary to mold this part?
3. Be prepared for some hard compromises. The filling analysis may identify an ideal location for the gate from a processing viewpoint, but building a mold with that gate location may be impossible or extremely costly, or the gate location may not be not acceptable from a product performance or aesthetics viewpoint. The simulation analyst should have access to sufficient design information to be aware of such restrictions and should have access to the design team to be able to explore any flexibility allowed in part design and application.
Experience counts. Repeat that 10 times. The ideal analyst has years of experience, not only with the software, but also has shop-floor experience in processing, materials, tooling, and part design. Each of these play a role in flow analysis and affect the quality of the results. Finding someone with this diversity of experience is unfortunately rare, so look for a shop that uses a team of these players to do the flow analysis. Try to find a team that will actually test the results on an existing tool. Request, perhaps demand, that they show you a case history where experiments on the tool matched their predictions.
Mold-filling simulation and analysis can tell you a lot about how well and how fast a mold will fill under a given set of conditions. But the accuracy of results depends on many factors, including the accuracy of the material data and the experience of the analyst in plastics materials, molding, and tooling. (Photo: Autodesk Moldflow)
Ansys Polyflow accelerates design time while shrinking energy and raw material demands for manufacturing processes. Polyflow helps to investigate the behavior of new plastics and elastomers. Virtual prototyping enables optimization and design exploration to reduce waste and overdesign.
Performing blow-molding simulation as well as structural analysis provides a method for companies to ensure reliability. Changes made to the manufacturing process can be directly related to final part performance through simulation.
In high-volume manufacturing, such as water containers, a minor reduction in material can drastically reduce costs and improve profit over time. However, reducing material can be risky without testing and design validation. Polyflow is the perfect software to analyze extrusion blow molding and simulate product behavior before any manufacturing attempts.
Ansys Polyflow contains high-performance solvers dedicated to polymer simulation. It is able to solve nonlinear material deformations and even has a novel meshing technique to distinguish tools from working materials. This is especially helpful for die design and can help you predict performance or reveal unexpected problems. The combination of these tools allows engineers to accurately simulate complex material behaviors and rely less on expensive and wasteful trial and error methods.
Ansys Polyflow includes a vast library of mathematical material models so you can understand and accurately characterize material behavior. Using the Polyflow material library, you can investigate behavior of new plastics and elastomers for applications as diverse as extrusion, blow molding, thermoforming, fiber spinning and film casting. Simulation enables you to test the ability to process new resins, even before they have ever been produced, by comparing prototypes for different materials to see if they match or outperform existing and competitive materials. You can reverse-design a resin to maximize end-product performance while minimizing costs and environmental impact.
Ansys Polyflow models include viscous heating to allow you to detect potential deterioration of a polymer grade or undesired rubber curing. Accurate modeling of high-temperature processes, such as glass forming, requires the use of advanced nonlinear material properties, accurate radiation prediction (using, for example, the discrete ordinate radiation model) and the Narayanaswamy model that accounts for material stress relaxation during the cooling process.
You can significantly reduce time to market by seamlessly exporting Polyflow results to Ansys Mechanical software to perform structural analysis. Using the data within Ansys explicit dynamics tools, you can conduct virtual drop tests and calculate top-loading deformation.
Designing equipment and processes for best results involves evaluating multiple designs and optimizing flow and geometric parameters. With Ansys Polyflow, you can declare any scalar as an optimization variable, including rheological parameters, boundary conditions and mesh displacements. Then you can use the built-in optimization algorithm to automatically minimize or maximize a given objective function based on input parameters. 2ff7e9595c
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