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Injection molding simulation of a new dimension

 

Europe and Asia, two simulation software provider that the 3D analysis is to solve a large number of injection molding injection products, the best way, but some well-known U.S. supplier does not agree. In any case, 3D modeling and simulation capabilities 2.5D standards are rapidly expanding.

Over the past few years, for the thick-walled workpieces of complex 3D flow simulation and for the traditional 2.5D medium-sized thin-walled workpiece surface analysis have made creative progress.

Now, molded with more choice of tools for software used to predict the injection flow of thick-walled workpieces, cooling, fiber orientation, shrinkage and warpage. Several well-known software providers such as Moldflow Corporation and Plastics & Computer Inc., has developed two kinds of 3D and 2.5D analysis software, new versions and enhancements, but they also encountered new competitors, such as Taiwan and Germany of Moldex3D Sigmasoft, almost without exception, these software focuses on 3D fields.

3D analysis is the first time applied to the Co-injection molding, multiple injection molding, gas-assisted molding, combined stack mold cavity forming and molding. The new three-dimensional simulation software analysis of fiber orientation and warpage, 3D technology, this is very important. Because 2.5D only show that fiber orientation in a plane, while 3D can indicate the orientation of fibers at various angles. Alleged in a simulated Cooling Road, mold cavity inserts, or the effect of metal composition, the new 3D software applications better than the 2.5D.

However, 2.5D software still is by far the leading simulation technology, recently launched for Microcellular foam (Trexel's MuCell process), and double-acting slide-valve gate (Synventive's Dynamic Feed) version. Now, a simple, low-cost 2.5D analysis software has been supplemented cooling and warpage analysis.  
Why 3D?
Suppliers believe that 3D simulation of increasing concern for several reasons. Over the past five years, many companies have been the challenges in the development of design limits of the workpiece, the workpiece is also the ability to test for the old emulation software, 2.5D is an experienced trial and error technology has been applied for 20 years. But for large, thick-walled workpieces, in particular, are complex, thin-walled workpiece simulation yield good results. The use of 3D simulation can be analyzed to small connector from the screwdriver handle a variety of workpieces. More recently, the majority of plastic workpieces are beginning to use 3D solid model for analysis. 3D simulation has just begun, many companies are using 3D CAD design of workpieces need to develop the 3D in the simulation and analysis applications. "

There are now more powerful computer can more quickly than in the past generation model and process analysis. This is for the 3D simulation is important because physical models of information than the 2.5 analog "intensive." Today's dual-processor computer, the model can generate time and reading time for 40% ~ 60%. With the 64-bit processors, gradually replace the current 32-bit chips and are expected to be similar in performance leap.

Bring the power of computing power applied to the complexity of the simulation, the use of Linux-based multi-processor servers, can improve the economics of the entire process. In aid of Moldex3D Linux Cluster analysis computation time is no longer a problem. The computer used to build models and rigorous review, Linux system used for digital reading. This configuration can quickly deal with a few million grid model, so the analysis of 3D simulation of the processing time will be close to 2.5D simulation time.

Surface or solid model

Plastics & Computer Inc. CEO Giorgio Bertacchi that the selection of traditional 2.5D software or a new type of 3D software depends on the workpiece geometry, complexity, materials, and the user desired analog data types. Under normal circumstances, the traditional 2.5D surface model in the best medium-sized application of an analysis of shorter thin-walled products. Complexity of a high degree of variation in thick or thin wall thickness of the product is best to use 3D analysis, although modeling of time may be longer.

Molding of the type (such as gas-assist, coinjection, over-molding, re-mold or a combination of mold cavity) also influence the choice of results, because the current model of these processes dedicated mainly 2.5D software-based, 3D version is still in development stage or have just appeared on the market.

But from another perspective, 3D analysis of the information provided is unmatched by 2.5D, like turbulence and laminar flow identification, molten material in the bubble, jet, and gravity and so on. 3D simulation can also learn mold their own situation. In the 2.5D simulation, embedded in an inlay in the mold pieces, you need to generate a grid, and then calculate how the heat through the inlay pieces. However, 3D simulation, when you enter the model, it can be observed temperature changes.

Although some applications that use the 2.5D simulation, but now more a workpiece can use 3D simulation. If a length 3ft, width 4ft, thick 0.1in car dashboard generated grid, with a standard tetrahedron yuan to do 3D simulations would be unrealistic because of the need for three-dimensional dollar too much. This is a medium-sized workpiece surface grid. However, the use of Moldex3D the new composite prismatic grid, you can do three-dimensional analysis of the workpiece. "This unique composite grid can be a model in the same mix of different size and shape of the three-dimensional element, significantly reducing the number of workpiece of three-dimensional element.

For relatively simple products, 3D simulation than the 2.5D simulation analysis time longer. Moldflow and other providers to develop similar to the MPI / Fusion of these products, allowing users to direct analysis of three-dimensional solid CAD models without the need to abstract out a medium-sized artificial surface. From the products to medium-sized three-dimensional CAD solid model surface model there is always a trade-off choices. There is no program can automatically manufactures a variety of geometric structures to generate a precise medium-sized face, need to manually extract the number of medium-sized face too many. For the complex structure of the workpiece, the human brain must be the best representation of medium surface to make important decisions.

Greet the new arrivals

In the Windows and Linux running on Moldex3D software series includes 2.5D "surface" and the new 3D "entity" version. Moldex3D Tsinghua University in Taiwan based on the study, developed by Core Tech System Co., Ltd. out. Core Tech has sold to more than 400 users of the technology, "seats," the majority of these users are located in Asia. In 1999, the company launched a Moldex3D to the world in English, and in last year's NPE show in Chicago on the Web.

Moldex3D features of the software is a novel compound entity element mesh method, is said to be more accurate than competing models, grid density, higher-, three-dimensional yuan less. Users can mix using a variety of three-dimensional element, including the tetrahedron, prism-shaped, tapered, and hexahedral. Analog products, thin-walled part, you can use the produce of several three-dimensional element of the prism-shaped grid. When the thick-walled part of the same product model, the software will automatically be converted to tetrahedral yuan.

Is said to use a different three-dimensional yuan yuan compared with using only a three-dimensional grid outline clear. Moreover, the "automatic flow channel grid" feature allows the user to click the mouse to generate an entity-based element of the flow channel system, while optimizing the grid density near the gate.

Recently, the program added to a group of advanced structural analysis software interface, including filling, compaction, cooling, warpage, fiber orientation, and reaction gas-assisted injection molding module. Recently released 7.0 version of the software to have greater material database (more than the previous 5700 brands), improved FastPack and FastCool solver and multi-processor. Able to simulate a total of injection molding, over molding and two injection molding of the 7.1 version is expected this year, together with the introduction of Linux-Cluster Edition. Using a variety of 3D geometry element to form a model is Moldex3D a unique feature. The software allows for more detailed regional grid is generated, in large flat areas to use fewer grid so that in a short period of time to simulate accurately.

Moldex3D developers are testing a new type of warp module, he will be warped products, "film" as a STL format model output, and then this model is the introduction of CAM software, allowing the mold are accurately mold cutting out the Alice Qu's "negatives."

CoreTech also can be inserted to provide a popular Solidworks CAD software package to run the module. Moldex3D Works only die filling simulation of 3D entities.

Aachen, Germany Sigmasoft company is fully committed to 3D simulations. It Sigmasoft simulation software in 1998, commercial. For Windows or Linux designed to Sigmasoft have a fully automatic mesh generation program, said that in 30 seconds to 2 minutes to complete its work within. Sigmasoft can also die model with a variety of inserts and the cooling pipe road together in order to more accurately observe the heat transfer within the mold.

Sigmasoft One unique feature of the software simulation products to leave the mold after the change, the calculation products continue to warpage after ejection and strain, until the products to reach ambient temperature. Some software can predict all the warpage after ejection, but the simulation is the product ejection Sigmasoft after 6000sec in change. With inserts for the mold, the software in the calculation of stress and warping will take into account the composition of the metal inserts and other factors.

Sigmasoft can be calculated when the filling pressure within the mold in order to determine the best location of the exhaust. This is very useful because the mold will produce compressed air inside the burning marks, especially when molding thermosetting plastic or other material to release gases.
Sigmasoft cycle analysis also has many features, you can repeatedly calculate the temperature inside the mold until the mold temperature constant down. This way than to assume a mold temperature should be more accurate. This feature can help understand the process of molding cycle of the heat accumulation. Users to monitor the simulation process to optimize the operation of the cycle.

Sigmasoft is developing a 3D multi-phase analysis software to deal with mold inside the two kinds of materials, such as gas and resin, or a total injection of molten material. Sigmasoft the next generation of software will have 43 dual-processor Windows-based functions, and thus the analysis time by 30% to 40%.

Three-dimensional simulation of gas-assisted injection molding

The use of the British newly developed simulation software for the first time on gas-assisted injection molding of thick-walled workpieces accurate three-dimensional modeling and analysis. Cinpres Gas Injection Inc. (CGI) using the University of Wales Institute of Polymer Processing Simulation and Design Center software. The software is the Center and the CGT's three-year joint projects. Director of the Center, said Dr. John FT Pittman, simulation process, including plastic in the mold filling. And the exhaust gases and cooling. Software entity tetrahedral or hexahedral simulation of various gas-assisted method - a short shot, run-off and counter-push.

CGT claims that this is now the only center on the product gas into the molten polymer and the interaction between the detailed simulation software. Pittman said: "We track the polymer and gas through the interface, solving both the flow problem."

Compared with the medium surface analysis, the software's highlights is that medium-sized surface analysis provide only part of the Jieqi product information section, while the performance of this software in detail, especially in the airway around the bend of the wall thickness changes. Analysis of cars and household goods such as thick-walled tubular handle when the value of products is particularly significant. The software can also be said to accurately predict the potential gas-assisted injection molding process, such as fingerprint phenomenon, a sudden spray, etc., and explain the delayed impact of gas injection, when plastic has been part of the cold.

Allegedly, this software can be generated within minutes of an appropriate CAD model of the grid, and in one day a moderate model (200,000 Finite Element) analysis - including plastic mold filling and the first and second gas infiltration . Pittman said the results of the analysis can be hollow plastic products, CAD models in the form of output, suitable for stress analysis.

About 3D and 2.5D for more info

Moldflow to its latest version of Moldflow Plastics Insight for MPI4.1 analysis software package developed several new modules, including the predicted fiber orientation, warping, and thick-walled workpiece in the thermal - mechanical performance analysis MPI3D module.

Moldflow software in its 3D extension to create the thermosetting plastic models. MPI4.1 can now be carried out 3D simulations of the hot runner. MPI3D can also be given injection pressure and clamping force and time curve. MPI4.1 support 64-bit computer, you can quickly create a large model.

Last year, in order to simulate Trexel's Mucell pore foaming process, Synventive's Dynamic Feed Sequential valve gate system (different nozzles have up to 32 separate pressure curve), and the second injection over-mold material and inserts plastic process, Moldflow to use the module to enhance its 2.5D software. Product Marketing Manager Peter Rucinski said that before the first injection material and the second injection materials analysis requires two separate simulations, and they may can not be reconciled, there is no way to simulate two kinds of material at the junction of interaction.

Warping prediction and analysis of the recent cooling efficiency added to the Moldflow Plastics Advisers (MPA) software, two new features. MPA is the early stage of development of products and molds designed for fast, low-cost assessed a simplified package. The new Performance Adviser and the Cooling Circuit Adviser module is the latest version of MPA7.0 part of it. These features previously only available on high-end MPI products.

Plastics & Computer Inc. for 2.5D and 3D analysis software package for adding several new features, one of which is in cooperation with the Italian Fiat Research Center, a four-year developed with faBest 2.5D software, filling, compaction and packing of the multiple injections of simulation. Plastics & Computer Inc. has also introduced software to create combination with medium-surface cavity mold and re-casting mold model function. It is worth mentioning that the company has been in the application of a medium-sized plane would be filled 2.5D modeling and simulation of 3D entities to combine patented cooling composite modeling method.

Plastics & Computer's 3D faSolid module has a fast solver, 3D analysis time can be reduced to 2.5D faBest module twice as high. Giorgio Bertacchi said: "Our modeling and analysis methods developed by taking into account the molder and mold business plans, work processes and organizational needs, so that providers can just mold and timely delivery of mold. This process can be repeated within a week Repeat 3D analysis to optimize the design. "

Two years ago, faSolid module extends the analysis of sequential valve gates. But so far most of the sequential model with 2.5D faBest fine work is done. Bertacchi think that when he used a 11-valve gate nozzle produced 6ft long model of the workpiece, he expanded the scope of that field.

Simulation of flow channel

An analog-only runner system rather than the mold cavity is Mold CAE Solutions that create a three-year software development company has been the focus. The company's MoldCAE topic was a fast, easy to use flow analysis program that can help optimize the hot runner and cold runner.

This process-oriented business modeling and mold designers, rather than the workpiece designer. CEO Bob Meng said: "There are too many people are talking about simulation and optimization of the cavity, but the design of the cavity, the user has the final say, rather than mold design and tooling personnel or operators. That they can really optimize the Molten material will be sent to the cavity system. They can change the cavity size of the layout and gate, balanced runner system, to obtain uniform pressure and filling. "

MoldCAE will help solve the asymmetric cavity filled with problems caused by the layout. It can simulate the combination of mold cavity molds and stacked die mold. The latest 4.2 version of the software can handle large models, including the 144 mold cavity PET preform molds.

MoldCAE special software, do not need to create CAD models, do not need to generate the network, so it has neither the 2.5D finite element and no 3D finite element. Users can simply guide the Institute of simulation software within 30 minutes of use. The user to enter the type of runner system, flow channel diameter, flow channel layout, the type of gate, gate number and location, type and injection molding machine plastic injection pressure data, and then simulate a few seconds to complete. Users can add or remove the gate, changing the size and location of the gate, after a few cycles and then modify the operation of the other analog data. Users can also add in the model of a simplified cavity design in order to better explain the needs of filling pressure.

MoldCAE special software calculating the maximum injection pressure and pressure and temperature in the flow channel and the cavity in the detailed distribution of simulated flow channel system, the shear rate, shear stress and shear heating, indicating the melting of materials throughout the system speed, lock mode power requirements, cooling time and short shoot. Convection Road and the gate of the software design, the best processing parameters of cavity volume and to make recommendations.

Simulation system has a database of commonly used thermoplastics, users can add new material in the database. Users can also build a typical gate, flow channel type and flow channel layout database.
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