Engineers are looking for ways to boost value and gain business. One example comes from Mazda, which is leveraging a plastic foaming process developed at MIT. Mazda’s injection molding process cuts part weight 20 to 30 percent by mixing supercritical fluid with plastic resin, such as nylon, in the injection barrel. The SCF causes the melt to expand rapidly when injected into a mold, requiring less resin. After initial injection, the mold core is precisely retracted, creating an outer layer with microscopic bubbles that ensure each part has the necessary strength and rigidity. The size of the bubbles in the core layer are adjusted to reduce density as desired, thus allowing control of the resin savings. Mazda says the technique can be used on most plastic car parts, and will be introduced on 2011 models.Mazda’s initial announcement called the technology proprietary, and Mazda has in fact been awarded patents for the development. Mazda, however, neglected to mention that the microcellular foam technology was developed at MIT and licensed to a Massachusetts company called Trexel. More than 300 molding machines use the SCF technology. Eighty-five discrete components have already been developed for use in cars, Trexel President David Bernstein told me in a recent meeting in Woburn, MA. MuCell works best with semi-crystalline engineering resins.
Mazda apparently did develop the concept of using core-back or “expansion” molding with the process, a brilliant idea. Trexel and Engel will be showing their approach to core-back molding at the National Plastics Exposition in Chicago June 22-26.
I’ll be posting more ideas on microcellular foam here at www.designnews.com, and writing articles for the print edition as well. One big issue I’ll explore is how the microcellular foam process can improve component properties.
As the 3D printing and overall additive manufacturing ecosystem grows, standards and guidelines from standards bodies and government organizations are increasing. Multiple players with multiple needs are also driving the role of 3DP and AM as enabling technologies for distributed manufacturing.
A growing though not-so-obvious role for 3D printing, 4D printing, and overall additive manufacturing is their use in fabricating new materials and enabling new or improved manufacturing and assembly processes. Individual engineers, OEMs, university labs, and others are reinventing the technology to suit their own needs.
For vehicles to meet the 2025 Corporate Average Fuel Economy (CAFE) standards, three things must happen: customers must look beyond the data sheet and engage materials supplier earlier, and new integrated multi-materials are needed to make step-change improvements.
3D printing, 4D printing, and various types of additive manufacturing (AM) will get even bigger in 2015. We're not talking about consumer use, which gets most of the attention, but processes and technologies that will affect how design engineers design products and how manufacturing engineers make them. For now, the biggest industries are still aerospace and medical, while automotive and architecture continue to grow.
More and more -- that's what we'll see from plastics and composites in 2015, more types of plastics and more ways they can be used. Two of the fastest-growing uses will be automotive parts, plus medical implants and devices. New types of plastics will include biodegradable materials, plastics that can be easily recycled, and some that do both.
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