Mold maker relies on simulation analysis for part accuracy
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By: Laura Carrabine
Wisconsin Tool and Mold Company (WTMC) is a mold maker and injection molder that primarily serves the medical and electronics industries. It operates 22 molding machines varying from 40 to 300 metric tons running six days per week 24 hours per day.
Over the years, the company has relied on CAE Services for high-end Moldflow analysis assistance on complex, hard to mold parts. WTMC President Hans Lang said, “Typically, when a customer sends us a thin-walled part design with several bosses, we know from experience that it will be hard to mold. That’s when Moldflow analysis really helps us.”
Flow analysis accurately simulates the filling and packing phase of the injection molding process. The software can simulate any number of part designs, runner sizes, gate locations, and processes. It creates a “what if” design environment before initiating the mold building process. The result eliminates typical trial-and-error methods.
Grill project
Recently, Mr. Lang approached CAE Services with a part for the iGrill®, a grilling and cooking thermometer that interfaces with iPhone®, iPad®, or iTouch® devices. The front cover was not filling properly which was causing severe air traps and aesthetics problems on the part surface (see Fig. 1) The objectives for this project were to identify the cause of the air trap, and to recommend a solution.
According to Tim Lankisch, CAE Services’ Director of Engineering, “We used the Autodesk Moldflow Insight midplane analysis module to run a baseline study, which correlated well with the filling pattern and the poor air traps. It was clear from simulation that the part design was the primary cause of the problem, and since the gate location was fixed, part design changes would be required to resolve their issues. The customer specified that we could not modify the thin areas that were the source of the problem. So, we had to be creative in modifying other areas of the part.”
As a result of using the technology, one of CAE’s engineers, David Stinson, determined the appropriate design changes. “The initial part design resulted in significant air traps in the thin window sections, and David’s solution was effective in eliminating them,” added Lankisch. The team made several design recommendations for their customer.
They included: >>
- Adding a flow leader between the gate and the thin window sections to push the air traps out from the thin windows;
- Thinning out several areas surrounding the windows such that there would be no race tracking around them to promote the formation of air traps;
The results predicted that the air traps would be eliminated, and after CAE did a final verification study with a true 3D model, WTMC incorporated the changes into the part design (see Fig.2). Molded samples confirmed the analysis results, showing that the air traps were indeed eliminated (see Fig. 3).
Moldflow analysis pays off
Mr. Lang noted that performing the analysis can be far less expensive than trial-and-error. “Once the CAE Services engineering team understands what type of part we need to mold, they can quickly turn a project around with their use of Moldflow. They really listen and I would recommend them to anyone who wants avoid costly errors and dissatisfied customers.”
Sometimes Lang receives a product design and the customer tries to dictate gate locations. The analysis may indicate a different and better gate location. “Using Moldflow and CAE Services’ experience, you can move gate locations and pin settings, as well as other details that will make the part stronger, better, and of higher quality,” added Lang.
“In today’s market, using Moldflow before the molding process lets you see on-screen exactly what is going on inside the mold. You can catch potential errors and optimize your part design. That is why we appreciate CAE Services. They are using the best technology to reduce the risk that something might go wrong,” Lang noted.
About CAE Services
CAE Services has been providing Moldflow software consulting engineering services since 1981. They offer a wide range of engineering services from structural analysis through warpage analysis. In addition, its corporate facilities house three molding machines ranging from 80 to 500 tons for mold sampling, analysis implementation, and analysis correlation. Its engineering staff is Expert certified. For more information, go to www.caeservices.com
