Metal-to-plastic conversion is the manufacturing process of making plastic components that can replace metal components, without sacrificing the performance or longevity of the final product. This also allows more design creativity, because plastic is easier to mold into complex and/or smaller shapes — sometimes one plastic part can even replace multiple metal parts.
What is even more impressive is that converting to plastic components can save up to 50 percent in operational expenses. Because plastic parts are so much lighter, considerable money can be saved on shipping and distribution costs, both for raw materials coming into the plant and outgoing finished parts and products. With these combined savings, metal-to-plastic conversion can be a big step in making U.S. companies more competitive with low-cost countries.
Use in Automotive
The automotive industry, in particular, has been taking advantage of metal-to-plastic conversion for years to meet stricter federal guidelines for improved fuel efficiency by 2025.
“Studies by the EPA and other organizations show that every 5 percent of vehicle weight removed can improve fuel economy by 2 percent,” says Marc Mézailles, global automotive industry manager for PolyOne Specialty Engineered Materials in Lyon, France. “Generally, replacing a metal component with a plastic one results in a 50 percent weight reduction, so the math is attractive to designers striving to reach corporate average fuel economy targets.”
Besides being lighter weight, components made from engineered plastics can be just as durable, heat-resistant, and corrosion-resistant as metal components, making them suitable for harsher, under-the-hood environments.
“Thermally and electrically conductive plastics now sport 10 to 100 times more conductivity than conventional plastics, a level equivalent to stainless steel,” adds Mézailles. “They’re making their way into heat sinks, EMI/RFI shields, and a range of components for hybrid electric and electric vehicles, such as connectors, power electronics, and infotainment modules.”
With these kinds of manufacturing advantages (especially lower costs), more companies from a variety of industries are getting on board. For example, plastic is replacing metal in automation equipment, pneumatics, instrument housings, medical devices, LED lighting systems, carts, folding tables, and even utility pole cross bars. In fact, plastics allow designers to be more creative because they can work with plastics that have specific physical and chemical characteristics that are better than those found in metals. What’s more, there are more than 25,000 engineered plastics available.
A key cost savings that doesn’t immediately come to mind is shipping and handling. Packaging and shipping products — especially larger or bulkier ones — that are 50 percent lighter than their metal equivalents can save a lot of money, especially when shipping long distances or overseas. There is also less damage during shipping. This can be a strong logistics advantage in highly competitive markets.
“For companies that haven’t worked with plastic, this probably sounds hard to believe,” says Al Elger, an engineer with Kaysun Corporation, a Manitowoc, Wisconsin-based injection molder. “But it’s true — with appropriate part design, plastic parts can be designed to perform just as well as the metal parts that are being converted to plastic. As material suppliers continue to develop high-strength thermoplastics that are increasingly impact-resistant, corrosion-resistant, and heat-resistant, we’ll see more companies convert from metal components to plastic.”