New near-net-shape molding technology yields stronger parts than extrusion or compression molding

Piper Plastics (Chandler, AZ) reports that it has developed a proprietary high-pressure molding technology that yields near-net-shape polymers up to 2 inches thick without porosity, voids or sinks.

The process, which utilizes molding equipment designed and developed by Piper Plastics, allows the company to mold filled or unfilled high-performance thermoplastics with isotropic mechanical properties. “This capability is especially beneficial for large CNC machined parts that were historically limited to extruded or compression molded stock shapes,” explained Dave Wilkinson, Materials Engineering Manager, in a prepared statement. “In comparison to extrusion and compression molding, this new process yields parts that have higher strength—typically 15 to 20% stronger than extruded shapes and 50% stronger than compression molded shapes—with more consistent mechanical properties.”

A major reason for developing the new technology was to save costs when machining finished parts from expensive, high-performance materials such as PEEK, PAI or TPI, said the company. “The molds are inexpensive, since we are only molding a near-net shape that will be machined after molding,” said Bruce White, Vice President, Piper Plastics. “Because it’s close to the final part, a near-net shape requires less machining. Less machining means less waste, which is an important consideration for green and sustainable programs.”

The technology also allows Piper to offer small batch runs for mating the right polymer or blend for an application. “Distributors typically only carry about 50 types of engineering plastics, but with this technology we can mold custom blanks from more than 3,000 polymers and compounds, or develop a compound specifically for an application,” said White.

The process is suitable for large parts and weights up to 6 pounds per blank, with large and varying wall thicknesses and complex geometries. “Near-net shape is effective for parts that cannot be produced using standard injection molding because the cross sectional area is too thick,” said Wilkinson. “This new technology has opened up exciting opportunities in the semiconductor, oil and gas, medical equipment and aerospace markets.”

A subsidiary of Quadrant Engineering Plastic Products, Piper Plastics supplies high-performance polymer materials and precision machined plastic components and assemblies to a range of industries.