Replace Metal with Plastic to Save Weight, Cost

Posted On May 25, 2017 By Tony Holtz

To decrease weight and potentially cost, you can replace metal with plastic on certain parts through 3D printing and injection molding. At Protolabs, we use industrial 3D printing process stereolithography (SL) to produce thermoplastic-like parts that have a nickel coating on the surface. This offers the increased strength of aluminum die-cast components, without the weight. With injection molding, the introduction of thermally conductive plastics has broken new ground when looking for heat dissipation of expensive heat sinks.

Stereolithography parts built with SLArmor have a metal coating applied over a thermoplastic-like base.

SLArmor involves a ceramic-filled DSM Somos material, which has a metal coating applied to achieve the look, feel and, most importantly, comparable strength of aluminum without added weight. SL is a cost-effective prototyping method for initial parts that mimic metal before moving to higher volumes of die-casted parts.

The material properties of SLArmor are greatly improved in regards to heat deflection, tensile strength, elongation at break and elasticity. The chart below shows exactly how the material relates to die-cast aluminum in three different thicknesses that can be applied based on geometry of SL parts. Note that the thickness of the nickel plating may vary on each part due to the ability to apply the coatings.


Do any of your parts require heat dissipation such as heat sinks? Traditionally heat sinks are produced from aluminum due excellent heat dissipation whereas plastics are known more for their insulating properties and lack of quality heat dissipation. But depending on how much heat dissipation is required, there are thermally conductive plastics that can work well.

You can’t always replace heat sinks with these plastics, but many components and products are starting to use the materials. Why? You can increase thermal conductivity to 50 to 100 times that of conventional plastics — a measurement of approximately 35+W/(m.k.) compared to 167+W(m.k.) for aluminum.

If that level of heat dissipation is suitable for your parts, you would also see benefits in weight and corrosion/oxidation reduction along with increased life expectancy of the parts. Thermally conductive materials are optimal for industries such as transportation, appliances, electrical, lighting and electronics.

If you are interested in knowing more about thermally conductive materials or SLArmor, please contact our customer service engineers at 877.479.3680 or [email protected]. To learn more about all of our 3D printing, CNC machining and injection molding materials, check out our resources page on materials.