Flow simulation often requires the user to manually create the surface layer. "The user had to specify a certain size mesh, be sure the size was good and ensure the aspect ratio was correct. It takes hours to manually clean the mesh and optimize the resolution of the model," says Carobus. These steps have been automated.
"We could not generate a mesh automatically with prism, pyramid and tetrahedral elements before," says Carobus. "R14 BLM 2.0 automatically meshes the surface … cleans the mesh and optimizes the resolution in approximately 30 minutes."
The company is upgrading the software to work with advanced processes, including MuCell microcellular molding, thermoset processing, injection-compression molding, encapsulation molding, multicomponent molding, venting calculation analysis and gas injection.
MOLDFLOW WORKS IN CAD
Autodesk Inc., San Rafael, Calif., repackaged its Moldflow software for plastics processing into three product groups, and shifted certain program modules from its high-end program to its standard program, says Hanno van Raalte, Moldflow product manager. This brings a range of higher-end modeling capabilities to more users.
The company now offers Autodesk Moldflow Design, Autodesk Moldflow Adviser and Autodesk Moldflow Insight, says van Raalte.
Moldflow Design helps determine how viable a design is. "The product is intended for the product designers, who typically are not plastic injection molding experts, but who will still make a lot of decisions based around part wall thickness and choices that impact final part quality," says van Raalte.
Moldflow Design quickly lets the product designer know if the part violates basic design principles for injection molding. Analysis tools validate the part and indicate whether the project is moving in the right direction, says van Raalte.
When the design tool was in the Moldflow Adviser software, product designers tended to use the feature after the product was designed, as a final part check. Autodesk moved the software into Moldflow Design, where it now works inside of a CAD environment. This allows designers to use it while they are designing the part. The software features many general-purpose molding design rules that are updated automatically, simplifying decision making.
"We typically see this being used by designers with some more knowledge about plastics and injection molding or [by] manufacturing engineers [to] help with critical decisions involved in the manufacturing of the part, like where to inject the part, and how to lay out the runners in the mold," says van Raalte.
Moldflow Design can determine a number of outcomes, such as whether a design will be problematic, or how the design affects cycle time. Software feedback provides information to make decisions regarding how to mold the part.
The company is also enhancing its Moldflow Insight simulation software, which runs modules for complex injection processes. Autodesk is expanding the capability of its MuCell microcellular molding module, developed in conjunction with Trexel Inc., Wilmington, Mass. It now can model MuCell foaming in conjunction with a coreback movement that produces parts with a solid skin and a foamed center. In coreback molding, the mold is opened slightly after the mold is filled.
Modeling the coreback step starts with accurate modeling of the polymer, which is infused with gas that is under pressure and dissolved. After injection in the mold, the surface layer begins to cool, forming a skin. Before the skin is completely solidified, the molder reduces the packing pressure on the melt. The drop in pressure causes gas that remains within the molten center to come out of solution. The gas creates a foam in the center of the part as the plastic volume shrinks while it cools.
The coreback step mirrors the movement of the mold core. The core moves away from the cavity a few millimeters, which accelerates gas coming out of solution, as well as the rate of gas expansion within the part. "The coreback step puts the foaming process on steroids," says van Raalte. This results in a part with a thin skin and a significantly larger foamed core with a larger and more uniform cell structure.
Autodesk has had the ability to model the MuCell process for 10 years, but combining it with a coreback step is a recent development — within the last two years. Interest in using Moldflow Insight with the MuCell module has jumped from one request a year to one request nearly every week, says van Raalte.
Autodesk has expanded the capability of the Insight software to model other types of foaming processes. The company has added the capability to model a traditional chemical blowing agent (CBA) in an injection molding process.
The user provides information on the amount of CBA that he or she plans to add to the resin. Insight applies a mathematical formula that determines how much the gas will expand. "It works out the size of the bubbles and the amount of bubbles," says van Raalte.
The calculation for foaming is of interest to automotive part suppliers seeking ways to lightweight parts, says van Raalte.
Insight software's ability to model fiber-reinforced materials has also improved. The software models short reinforcing fibers, long-fiber materials and continuous-fiber composite structures. Unidirectional weaves or tapes that provide local reinforcement to a part can be modeled and the final shape of the whole structure can be determined, says van Raalte. In the process, users can create a stiff, lightweight structure with a composite shell, with overmolded technical components like ribs and bosses.
In addition, work is being done to model compression molding of sheet molding compound (SMC) for large part automotive applications. "The American market is starting to come on board with it, using it for large body panels," says van Raalte. Large automotive body panels typically made from a thermoset material can be created with SMC compression molding. But long resin-curing times, ranging from three minutes to longer than five minutes, have made it impractical to use SMC compression molding in high-volume automotive projects. Resin suppliers have recently created resins that have a shorter curing time, closer to one minute, says van Raalte.
The Moldflow Insight package also has new modules developed to simulate rapid heating and cooling technology in the mold, where a high-gloss finish is required.
Autodesk partnered last year with RocTool SA, le Bourget-du-Lac, France, to offer a simulation of its induction heating technology.
The newest version of the Moldflow Insight Premium now features the ability to simulate the movement of a valve gate designed to open slowly. Valve gates — and the programs used to model them — have in the past had designs that offered only a capability to be fully open or fully closed, rather than incremental movements. Newer designs from several suppliers have the ability to open gradually, which minimizes flow front acceleration and temperature fluctuations, says van Raalte.
Profiling the valve-gate opening results in better part surface quality and pressure profiling, he says. Autodesk is now incorporating valve-gate movement into its simulation software. Users now can model instantaneous or delayed valve-gate movements.
SIGMAN AUTOMATESAND ADDS PROGRAMS
Sigma Engineering GmbH, Aachen, Germany, has updated its Sigmasoft virtual simulation software to expand the types of plastics processes it can model.
Sigmasoft models filling, packing, cooling and warpage, as well as overmolding, multicomponent molding, gas-assisted molding and molding with thermoset materials. Version 5, the current version of Sigmasoft, has been available for the last year, says Matt Proske, VP of Sigmasoft virtual molding.
The software automatically bridges larger and smaller points of calculation, ultimately allowing for a reduction in element count for the mesh, which speeds simulations. In addition, Sigmasoft is able to run effectively on a CPU with multiple processing cores.
"A single-core processor was able to do one thing at a time. Two cores means two tasks can be run," says Proske. Users can now run Sigmasoft on computers with up to 32 cores, which can improve the speed of the mesh generation up to 500 percent. Users can select the number of cores in the CPU for use with the simulation software.
Sigmasoft has upgraded the elastomer and thermoset programs to better model curing and shrinkage. "As these polymers cure, their molecular structure is cross linking. There is a certain amount of shrinkage that is related to that activity, and we can now simulate that," says Proske.
Knowing the degree of shrinkage from thermal changes and the degree of shrinkage due to curing helps the model more accurately render the final part shape. The program upgrade is ideal for thermoset materials like two-part epoxy or elastomers like silicone rubber or natural rubber, says Proske.
Sigma also upgraded the program for modeling the use of long-glass fiber, fiber breakage and fiber damage. Sigmasoft uses 3-D elements to simulate the flow behavior of the filled polymer, enabling users to see the flow of polymer through a wall section, or predict fiber orientation on the surface or inside of a part, says Proske.
Sigma also updated the water-flow model. Using what Proske calls computational finite difference, the software can incorporate the water line into the simulation. "It can calculate and simulate in 3-D the flow of water through the water circuit. It can determine if the cooling design will work, how effectively or ineffectively it cools, and can show how much heat the water can pull from the mold surface," says Proske.
Sigmasoft says Version 5.1 of the software, to be released in the next month or two, will feature a new user interface for ease of use, but will also have a new program for creating better part geometry inside the simulation.
The interface will make it easy to find a specific variation of a project and will inform users which version of a project they are viewing; and provide details as to whether a simulation was run from that version and what the results were, as well as objectives of the project and more.
VERO SOFTWARE SIMPLIFIESCOOLING CHANNEL CREATION
Vero Software, Cheltenham, England, has enhanced its simulation and mold design capabilities with the release of VISI 2016 R1. TST Tooling Software Technology LLC, Clarkston, Mich., distributes the software in the U.S. and Canada.
The VISI Mold portion of the VISI software helps the user to create, define and edit cooling channels during mold design. Users can bring the CAD image of a cooling channel into the software seamlessly, says James Kesteloot, program manager at TST. All cooling parts associated with the cooling channel, including solid, 2-D and standard elements, are automatically selected. Previously, the user had to manually model the cooling channel, selecting the type and position of each element.
Users can create a cooling line based on a template of selectable elements. Data from the cooling channel design — or the simulation run with it — can be saved and propagated throughout the tool or used with another tooling design, says Kesteloot. A new user interface features icons for a range of standard cooling elements, which users can employ to add an element directly to a cooling channel sketch.
VISI Mold also has a new menu command that allows for the automatic creation of lubrication grooves in a tool plate, which allows for easy customization and adjustment, says Kesteloot.
The VISI Flow program can handle a wider range of materials via a larger materials database that better models glass-reinforced, glass-coupled and long-glass reinforcement, says Kesteloot.
VISI Flow has also been enhanced to determine linear shrinkage values and calculate part shape better, says Kesteloot.
Vero announced several other updates included in VISI 2016 R1 that focus on the CAM features and the range of machinery, design and molding applications. (See Product Innovations, page 40.)
Mikell Knights, senior correspondent
[email protected]
Contact:
Autodesk Inc., 415-507-5000, www.autodesk.com
EPS FloTek, 630-778-7773, www.epsflotek.com, www.moldex3d.com
Sigma Plastic Services Inc., 847-558-5600, www.3dsigma.com, www.sigmasoft.de
TST Tooling Software Technology LLC, 248-922-9293, www.tst-software.com
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