Incredible material and processing gains have transformed the molding industry from thermoforming, injection- and blow-molding with basic resins into a high-tech industry with limitless options. Ken Kincaid, Technical Engineering Manager at Mack’s southern operations, looks at nanocomposites, water-assist molding and other new technologies on the plastics horizon.
Nearly 40 years ago, Mr. McGuire predicted there would be “a great future in plastics” in a conversation with young Ben Braddock in The Graduate. Today, we have progressed far beyond anything Mr. McGuire could have possibly imagined.
Injection molding has blossomed into structural foam, gas counterpressure, thin wall molding, gas-assist and more. Molding machines no longer have knobs and dials. We process through closed loop computer controlled process controllers. Many machines aren’t even hydraulic or toggle anymore, they’re all electric. Very quiet and clean. Operators generally perform secondary operations as the machine deftly extracts the part from the mold and gently sets it on a fixture or table to be converted to a finished product.
We no longer think of ourselves only as molders. We are suppliers of technology and advancement. Among the long list of offerings are contract manufacturing, design assistance, program management, purchasing support and an infinite number of variations of these services. Each one individually tailored to the customer’s needs. We routinely participate with our customers in cost reduction programs, weight reduction programs, and material conversion programs, all designed to help maximize their effectiveness in the marketkplace.
Not only have machines and services changed. Materials and processes have progressed even further. Take nanocomposites, for example. Who would have thought you could add microscopic particles of finely ground clay with an aspect ratio roughly that of the average business card to increase stiffness and improve dimensional stability without affecting color or adding weight to the part? This technology is now being used increasingly on interior automotive panels to improve fit and finish without adding weight or reducing impact qualities of the base resin.
Water-assist is also creating a stir in today’s plastics technology circles. Imagine having the ability to core out thick sections of a part from the inside, much like gas-assist does. Only by using water, you can not only increase the pack pressure to improve surface finish, but because the water also cools the part from the inside, it will improve wall thickness consistency and reduce cycle time reportedly up to 75 percent. For the more conservative types, it’s very acceptable to design a part to be built in a gas-assist process and, after confirming the design, convert it to water-assist and reap the benefits. Although this process is being targeted for all sorts of handle and tube type applications, it could probably be used in many other gas-assist type applications, as well.
Other incredible material and processing gains include long glass additives, which can generate flex modulus numbers in the seven-digit range. There are custom colors and other additives that do everything from glow-in-the-dark to kill germs on contact. Blending resins can give you an olefin-based resin with the feel of PVC, the weight of HDPE, and a cost and moldability approaching that of polypropylene. We can overmold to create dual durometer parts, as well as parts with structure on one side and high cosmetics on the other. Film insert molding allows us to place a highly cosmetic, endlessly decorated thermoformed film into an injection mold and mold a substrate with almost any features needed to support or attach it.
After all these years, the future is still in plastics…the only difference is you can hardly keep it to just one word!
If you’d like to learn more, contact Ken Kincaid, Technical Engineering Manager, Mack Molding, firstname.lastname@example.org
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