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A car in a factory

3M™ Glass Bubbles for sheet molding composite

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Sheet molding composites – lighter weight for more automotive applications

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  • In some applications, sheet molding composites (SMCs) are used as a replacement for heavier composite materials or metals in automotive designs. 3M Glass Bubbles – tiny, hollow glass microspheres that replace the dense fillers commonly used in SMC production – can enable ultralightweight SMCs and Class A paintability to replace heavier steel and aluminum body panels, hoods, trunk lids and more.

    3M Glass Bubbles are available in grades that withstand the high isostatic pressures in the sheet molding process with minimal breakage. In fact, SMC can now be as much as 45% lighter than standard density SMC. Let’s talk about your needs for lightweighting SMC automotive parts.

3M Glass Bubbles for sheet molding composites – inside and out

3M Glass Bubbles can enable densities below 1.0 g/cc and a total SMC component weight reduction of 40 - 45%, making ultralightweight SMC an option as a replacement for metal parts in more places on the vehicle.

  • A red exterior component of a car
    Exterior components

    Pictured: Standard density SMC panels weighing 2.5 kg/5.5 lbs can be reduced to 1.8 kg/4.0 lbs using 3M Glass Bubbles.

    Class A paintable finishes: While fillers can sometimes affect the final part surface, compounders and resin suppliers can still produce lightweight SMCs with a Class A Paintable finish.

    Recommended products:

  • Lightweight SMC panels with 3M Glass Bubbles
    Interior components

    Pictured: Lightweight SMC panels made with 3M Glass Bubbles.

    Recommended products:

Customer case studies

  • Glass bubbles lift Corvette body panels to top SPE award PDF
    3M Glass Bubbles lift Corvette body panels to top SPE award
  • 3M Glass Bubbles CSP Case Study (2016) - Sheet molded Composites PDF
    3M Glass Bubbles CSP Case Study (2016) - Sheet molded Composites

A desktop computer with a graph/calculator to calculate how much weight you could save with 3M glass bubbles
Calculate how much weight you could save with 3M Glass Bubbles.

See how 3M Glass Bubbles can help you reduce the density of your compound formulations, leading to lighter weight parts. This weight volume calculator allows you to compare your reference compound formulation with lighter formulations that use 3M Glass Bubbles.


Application areas for lightweight SMC

Automotive body with each 3M solution shown for interior and exterior applications.
  • 1. Trunk bed

    2. Trunk lid

    3. Sunroof frame

    4. Sunroof curtain

    5. Glove box and interior compartments

  • 6. Engine hood

    7. Front trunk bed

    8. Noise reduction parts

    9. Headlight assembly

  • 10. Front end module

    11. EV battery housing

    12. Door panels

    13. Structural SMC

    14. Side body molding

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Send us a message

3M supports our Glass Bubbles with global sales, technical and customer service resources. Contact us for more information, including formulation assistance or questions about a specific application.


ORLANDO – May 7-11, 2018 – National Plastics Expo, Booth #S27153 – As automotive manufacturers look to improve fuel economy and battery range for electrification, material lightweighting without compromising mechanical integrity is vital. Metals, although lightweight, can come with indirect processing and manufacturing costs and may become even more expensive with the uncertainty surrounding global metal supply. Sheet molded composites (SMCs) are a viable alternative to metals in certain applications, while still achieving the desired physical properties. 3M today introduces Glass Bubbles S32HS to help OEMs achieve up to a 40 percent weight reduction of composite parts, at a density below 1.0 g/cc, while still enabling a class A paintable finish. This innovation makes SMCs an attractive option in automotive design for OEMs.

“With the trend toward electric and high efficiency cars, reducing overall vehicle weight is key to staying competitive,” said Ray Eby, vice president of 3M Automotive Electrification. “A typical automobile has about 660 lbs. of composite parts. With ultra lightweight SMCs enabled by our glass bubbles, OEMs can significantly improve a vehicle’s energy usage, while saving money– one less bump in the road in the race to automotive electrification.”

For many years, 3M has partnered with the automotive industry to enable weight reductions for major automotive manufacturers. By replacing conventional fillers, these hollow glass microspheres can reduce the weight of molded parts without sacrificing strength or aesthetics. For the first time, 3M has been able to break the density barrier, making ultra lightweight SMCs more competitive to steel and aluminum, opening up new possibilities for the material mix in automotive applications.

“Our customers continue to challenge us to lower the density and weight of fiberglass reinforced material systems to support their automotive lightweighting efforts,” said Terrence O’Donovan, vice president, marketing and sales for Core Molding Technologies. “A density of 1.0g/cc or below has long been a goal, while still enabling a Class A finish. Using 3M Glass Bubbles helps enable us to meet our customers’ expectations.”

3M glass bubbles are an established lightweighting technology used in enabling lightweight sealants, injection molded parts and SMCs. 3M continues to be at the forefront of automotive lightweight material innovation with the launch of Glass Bubbles S32HS.