In contrast to the tangible machines and molds on display at both Plastics Encounter Midwest and the MoldMaking Expo, some companies demonstrated the capabilities of their mold-designing software.
Fully three-dimensional mold-design tools are becoming more prevalent in the plastics industry. The capabilities of the programs are growing as quickly as the technology behind them, according to three suppliers of software for computer-aided design and manufacturing, and mold-filling simulation exhibiting at the Cleveland trade show.
Delcam plc, a Birmingham, England-based supplier of CAD/CAM software, has added PS-Moldmaker to its PowerShape program. PowerShape is a hybrid modeler; it mixes surface and solid modeling. Developmental director Stuart Watson noted that molds can be complex shapes, and all the crevices and holes in them make it necessary to use a hybrid program that can handle surface and solid modeling.
PS-Moldmaker is fully integrated with PowerShape. ``Basically, it's a series of wizards to help with common procedures,'' Watson said. Wizards automate procedures like core-cavity splitting and creating die inserts and cavity impressions.
Watson said the key to efficient design is having a hybrid modeler. ``About 50 percent of mold makers' tool design is still done in [two dimensions], in AutoCAD,'' he estimated. ``It's an inefficient process, wasting time and money. In the last few years, there's been a trend toward 3-D solid modeling.''
Naples, Fla.-based Kruse Analysis Inc. also boasts a completely 3-D simulation software for injection molding. Kruse sells and works with Sigmasoft, modeling software produced by Sigmasoft GmbH of Aachen, Germany.
President Torsten Kruse said the days of designing molds and mold parts in ``21/2 dimensions'' are fading fast. ``Fifteen years ago, everyone was designing in 21/2-D. Now I would say 90 percent of the designing world is true 3-D, and in the next two to three years I think everyone will be fully 3-D,'' Kruse said.
With Sigmasoft, solid geometric models of a part and mold can be imported from CAD systems and meshed into a fully 3-D model.
Before selling a mold that may cost hundreds of thousands of dollars, mold makers want to test their design to make sure it will work properly. After Sigmasoft creates the fully meshed 3-D model, designers can run tests allowing the user to calculate anisotropic stress, residual stress and distortion.
``If you don't take into account the stresses, you're not being as accurate as you could be,'' Kruse said.
The program can simulate the entire injection molding process, including the heating and cooling of thermoplastics and thermosets. It also can simulate two-shot molding, inserts and fiber-reinforced components.
``We simulate how material flows through the mold - not only the part, but the cavity. We can predict jetting [and] venting. We take the gravitational effect into account,'' he said.
Kruse said Sigmasoft is suited for complex parts that make up the top 10 percent of the market.
However, SolidWorks Corp. is appealing to a range of part manufacturers. The company has 325,000 users in production and reported sales of $160 million for 2003. SolidWorks recently collaborated with Wayland, Mass.-based Moldflow Corp. to create MoldflowXpress for SolidWorks 2005.
``SolidWorks users can now run injection molding analysis,'' said Ryan Stulak, eastern sales director. ``MoldflowXpress lets them know if the part can be molded the way it's designed, and points out the problems if it can't,'' he said.
MoldflowXpress will be accessible for prior SolidWorks users, Stulak said. It will be a drop-down menu inside the SolidWorks program. MoldflowXpress predicts whether a 3-D solid model of an injection molded part will fill based on geometry, injection location, type of material and processing conditions, the company said.
``We believe that once users experience the benefits of analysis early in the part design stage, they will make it an indispensable step in their product-creation strategy,'' said Roland Thomas, Moldflow president and chief executive officer.