Design Center Helps Bring Complex Injection-Molded Part to Market

Parts evaluation at the design stage facilitated company's production process

A manufacturer of medical devices used worldwide in cardiac catheterization labs was designing a new product that would require multiple gates and a complicated configuration for an injection-molded part.

Merit Medical (Salt Lake City) wanted to evaluate the product design while it was still in the computer-generated prototype stage, to identify processing and manufacturing issues critical to the final success of the project. However, the company did not have the in-house capabilities required to do a proper analysis.

A development specialist at M.A. Hanna runs an evaluation of a part, while still in computer-generated prototype stage, to identify critical processing and manufacturing issues.

Merit turned to M.A. Hanna Resin Distribution (Cleveland) to review the project and make recommendations using advanced computer engineering tools.

With technical support provided by Hanna's design center, Merit Medical was able to review options and make critical decisions by weighing multiple factors for tooling before manufacturing. Mary Sinnott, project leader for Merit Medical, says it was a very worthwhile experience. "The product we were working on is very complex, with multiple components and intricate channels and valves. Evaluating where the knit lines would be and how we could adjust their positioning was very important."

Chris Harton, senior development specialist for M.A. Hanna, ran the evaluation of the part. Before his team did mold-flow analysis, they looked at the computer-generated model and made some initial suggestions that would help in processing and production. Harton says, "We did the analysis to determine the optimum gate locations to minimize weld lines. Other work involved looking at injection times and melt temperatures. Each step gave us different parameters and choices to evaluate."

The final phase of the analysis involved using new CAD/CAM software to examine the thickness of the part wall. "This is brand new," says Harton. "It allows us to look at the entire thickness of a wall rather than just at the midplane."

"The gating information was very important," says Sinnott. "At the design stage we were able to identify and minimize backfilling in critical areas. This process is valuable for designing challenging parts."

M.A. Hanna's design center offers advanced technical support in all areas of plastic application design, development, and manufacturing. Capabilities and services include CAE for product design using a 3-D solid modeling CAD/CAE system, finite element analysis for optimized part performance, and mold-fill analysis to provide guidance for tooling and final part performance. Other services include a range of analytical capabilities such as thermal analysis, Fourier transform infrared spectroscopy, atomic absorption spectroscopy, gas chromatography, polymer identification and selection, surface analysis, moisture determination, custom-compound formulation, prototyping, and physical testing.

Merit Medical is currently configuring its new product, which is expected to go to market midyear. The design and configuration of the tool was facilitated by the extensive capabilities and technical support services provided by M.A. Hanna Resin Distribution.

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