3M banks on new lightweighting tech

That automotive lightweighting is one mega trend in global industry is well known but there have also been crucial technological breakthroughs in the areas of metal substitution and high-tensile plastic polymers and rubber parts. Driven by the increasing demand to reduce greenhouse gas emissions, automakers are in a race to find alternate and innovative ways to improve the fuel efficiency of primarily passenger cars and commercial vehicles. Besides increased efficiencies, other factors such as new legislation, increased comfort and convenience, aesthetics and aerodynamic design are also driving efforts in this direction.

Explaining the cause, Anil Hak, general manager of 3M’s advanced materials division, says: “This has led to extensive research into new materials that are lighter in weight without compromising on performance. For example, automotive plastics have been extensively used for years to replace metal parts, shaving off hundreds of pounds of kerb weight. Today, research is focusing on new, low-density plastics compounds that reduce part weight even further, while maintaining an acceptable balance of performance and processing characteristics.”

One closely related technology is 3M’s glass bubbles which are high-strength polymer additives, which can be used as low-density filler material into the plastic and rubber parts through various processes. Highlighting 3M’s focus areas, Hak says that “3M has multiple technologies focusing on reducing weight in the automotive vertical.Some of the major efforts by 3M in India have been in the areas of advanced lightweight solutions for noise-vibration and harshness (NVH) and acoustic requirements, the lightweight structural adhesives to replace rivets and fasteners and the glass bubble technology for lightweighting of plastic, rubber and composite parts, plastisols and seam sealers.”

WHAT IS 3M’S GLASS BUBBLE TECH?

3M glass bubbles are high-strength polymer additives made from a water-resistant and chemically-stable soda-lime borosilicate glass. These hollow glass microspheres can be used as a low density filler material, claimed to be ideal for plastic and rubber parts created from injection moulding, extrusion processes, and/or other vigorous processing equipment (such as banbury mixers and others), offering improved processing over many conventional fillers.

According to Hak, the glass microspheres are more effective as compared with the conventional and heavy fillers such as talc, calcium carbonate, glass fibre, and clay (which range from 2.5g/cc to 2.8g/cc in density). The glass microspheres, on the other hand, used mainly for plastics and rubber applications, have densities ranging from 0.1 to 0.6 g/cc, making them excellent strength and weight optimisers.

“Replacing a certain percentage of conventional high-density fillers with glass microspheres results in weight reduction while maintaining the original mechanical properties,” adds Hak.

Citing an example, he says that “challenged by a major automotive OEM customer to find innovative ways to reduce parts weight without sacrificing mechanical or aesthetic properties, a leading global supplier of interior plastic trim components has achieved weight reduction in the range of 5-13 percent in a number of its key components, by replacing conventional talc filler with 3M glass bubbles in a proprietary polypropylene compound.”

Similarly, according to Hak, a leading sheet moulded composite (SMC) manufacturer has achieved a weight reduction of nearly 28 percent over its conventional counterpart. Elucidating the case, Hak says that “the weight reduction achieved is 5.3kg for the hood of an SUV. Using standard construction, this 48” x 65” hood assembly weighs 18.4kg. With glass bubble composition, the hood’s weight stands reduced from 18.5kg to just 13.15kg, thus enabling weight reduction of nearly 28-29 percent. The reduction is accomplished with acceptable structural properties since our strength tests show that the lower density parts constructed with 3M glass bubbles fall within the standard deviation of prospective new OEM dimensional and safety specifications.”



BUNDLE OF OTHER BENEFITS

According to Hak, besides reducing the weight of specific components, the technology is beneficial for other crucial factors such as it helps in improving the dimensional stability, reducing shrinkage and sink marks, and also contributes to material and process cost savings.

“They are an ideal additive material for applications in the automotive, heavy trucks (HCVs), aerospace, oil and gas, electrical, sports and leisure, electronics, appliances and durable goods industries, as well as in construction products such as polymer/wood composites and siding – helping not only to reduce part weight, but also to improve dimensional stability and nail-ability,” underlines Hak.

However, at the same time, he firmly believes that high-performance engineered plastics are not the only cost-effective answer to steel/metals for lightweighting. “But, yes, plastics are growing in popularity in this area,” he admits.

3M in India works closely with the raw materials value chain and has a local R&D team which works on developing innovative processing methods to compound and mould glass bubbles-filled plastic parts. 3M’s R&D team also works closely with various stakeholders in the value chain, ranging from OEMs, moulders and compounders to resin suppliers developing tailor-made applications in lightweighting.

“We work closely with some of the major polymer and master batch manufacturers in India and globally. We work with OEMs and moulders to identify their pain areas and weight reduction requirements they have in their platforms and parts. On identifying the specific parts, we initiate joint development with various stakeholders in the automotive value chain (moulder, master batch manufacturers, resin manufacturers) to develop the lightweight parts using the glass bubble technology,” concludes Hak.