SPE ACCE 2015 show report

The Society of Plastics Engineers (SPE) Composites Division organized the 15^th edition of the Automotive Composites Conference and Exhibition (ACCE), and as in every year, it was the largest event so far. That speaks not only to the fact that event organizers, including CW contributors Peggy Malnati and event co-chair Dale Brosius, did a great job, but also to the auto industry’s ever-growing interest in composite materials. Was this the year, finally, for the big break-through for automotive composites? Maybe, depending on to whom one talked or the presentation one heard. But, a BMW i8 with carbon composite Life Module was prominently on display in the parts area, along with some other interesting and actual in-production composite parts. That’s pretty firm proof of the distance the event has traveled over the past decade and a half.

After a welcome by Brosius and co-chair Fred Deans, chief marketing officer at Allied Composite Technologies LLC (Rochester Hills, MI, US) that included best paper awards and student scholarship winners, Russ Broome, managing director for SPE US, accepted $20,000 from SPE’s automotive division and composites division ($10,000 each) for the Dr. Jackie Rehkopf scholarship, administered by the SPE Foundation. Broom noted that his goal is to begin providing scholarships at the high school level: “We need to get kids interested in plastics and composites earlier, so that they’re prepared to enter polymer programs when they’re ready for university.”

Three simultaneous tracks over three days provided conference-goers with a wealth of technical learning opportunities, with an emphasis on ways to improve parts and production speeds while reducing costs. A three-part Nanocomposites track included several papers on nanocellulose, available as cellulose nanofibrils (CNFs) and cellulose nanocrystals (CNCs) and ways to use them in biocomposites. These bio-based materials, generated from a broad range of both trees and agricultural biomass, are abundant, price-stable, have relatively high strength and modulus, are optically transparent, provide a permeation barrier to oxygen (because of the tortuous path created by the fibrils), a high strength-to-density ratio (higher than carbon fiber), and a lower density than most traditional resins fillers such as talc or calcium carbonate, says Kim Nelson, vice president of nanocellulose technology at American Process Inc. (Atlanta, GA,US). While CNFs and CNCs are not new, her company has a way of producing them in larger quantities, at a lower cost and with greater stability. The nanocellulose can be functionalized and compatibilized for specific resins, and made either hydrophilic or hydrophobic for specific applications. She notes that American Process CNCs and CNFs are able to withstand temperatures 50-100°C higher than other nanocellulose on the market. The bottom line is that nanocellulose filler can improve resin performance in many applications, including plastics and composites molding. The company is working with Futuris Group (Port Melbourne, Australia), a provider of seat components for Tesla cars, and with Oak Ridge National Laboratory (ORNL, Knoxville, TN, US) on improving 3D printing resins.

Also in the nanocomposite track, Kunal Kumar, senior technical service representative from Evonik Corp.’s (Richmond, VA, US) Richmond Business and Innovation Center, spoke about his company’s nanosilica solution for tougher resins. Nanopox, at 20 nm in diameter, is intended for addition into fiber sizing formulations, at very low concentrations (less than 2% by weight). The silica particles improve compression strength, lower coefficient of thermal expansion (CTE), have no influence on the resin’s Tg, and are a cost-effective way to toughen automotive parts that must be damage tolerant. At the other end of the nanosilica spectrum, 3M’s (St. Paul, MN, US) James Nelson described how his company adds nanosilica at loading up to 55% weight percent into resins, for applications like filament winding of pressure vessels or drive shafts. Based on extensive testing, Nelson says the particles improve virtually every characteristic of its 3M 4833 matrix resin, including less shrinkage, lower exotherm, better mechanical properties, with higher density being the only drawback.

The session track “Opportunities and Challenges with Carbon Composites” offered up some new information, including Michael Karcher’s description of an experimental program at Fraunhofer ICT for producing carbon prepreg materials inline, and in-house, for greater cost efficiency and higher production rates. Max Thouin, technical sales manager for Mitsubishi Rayon Carbon Fiber & Composites Inc. (Irvine, CA, US) gave an interesting presentation on automation of preforming for compression molding, using 2D layup of towpregs, rather than slit tape. The towpreg is able to move and shear easily for better conformability during part shaping, and scrap can be significantly reduced, making the process much more cost effective. Thouin emphasized the importance of creating a lower-risk and more robust composites processing supply chain as the key to getting more traction in the automotive sector.

Brian Gardner of Sigmatex (Benecia, CA, US and Runcorn, UK) described SigmaRF made with recycled carbon fiber waste from his own company’s product lines. The fibers are realigned, comingled with polypropylene or polyamide matrix fibers, then rewoven to form a fabric. Because the fibers aren’t continuous, the fabric is essentially a stretch-broken type, with good drapability and conformity to a mold surface. Gardner claims that a Class A finish is possible with the materials, in a sub-four-minute process, using PA6,6 resin, retaining 85% of virgin fiber modulus and 50% of virgin tensile strength, and exhibiting better impact properties and damage tolerance than a continuous fiber product — at significantly less cost. Sigmatex is open to accepting customers’ waste carbon streams, he added.

In the same carbon fiber track, Hexion’s (Columbus, OH, US) Stephen Greydanus gave an overview of the current state of automotive composites, based on industry presentations, available studies as well as his company’s involvement. He presented a very interesting slide of BMW’s new 7-Series Carbon Core concept, which places braided carbon/epoxy structural elements inside the B and C pillars, roof bows and chassis elements to form a strong structural cage around the occupants, a design that drops about 41 kg from the body-in-white. While noting that part size and complexity, mold temperature and specific equipment determine the material processing window, Greydanus says that a part with simple geometry, in a liquid compression process, can be made in as little as 50 seconds with the company’s resin materials (and preform binders).

Natural fiber composites were discussed at length. National Research Council Canada and University of Guelph were representatives, as were material suppliers to this growing market segment. BASF’s (Ludwigshafen, Germany) Henning Karbstein gave a dynamic presentation about his company’s Acrodur binder system, essentially a water-based acrylic dispersion to bind natural fibers together. In addition to thermoset versions, he discussed a new thermoplastic version (Acrodur Power 2750 and 4444, introduced at the 2015 JEC Europe event) that now allows both cold-pressing and hot-pressing for auto interior components, as well as back injection molding. His story: the product can replace polypropylene in an interior part, for lower weight (since less binder is needed, as compared to PP); it results in a higher fiber volume fraction (for better structural performance); and the system gives the ability to add pigments or fire performance fillers to a natural fiber part (since the Acrodur binder is an easily-modified liquid). Another standout was Atul Bali of Competitive Green Technologies (Leamington, Ontario, Canada) who discussed his company’s success at commercializing a variety of bio-based composites, initially developed at Guelph. BIOBLAKR is one example; it is a bio-sourced alternative to carbon black, with a significantly lower density than the traditional carbon product, and is able to take very high in-service temperatures.

Some other standout presentations included one by Pinette Emidicau’s (Troy, MI, US and Chalon Sur Saone, France) Andrew Rypkema, who discussed the “QSP – Quilted Stratum Process” for automated preforming. The innovative automated line will be unveiled November 3 at the Technocampus in Nantes, France.  Another was a paper by the American Chemistry Council’s Michael Day and Michigan State University’s Dr. Mahmood Haq, who described research on reversible bonded joints using nano-ferromagnetic particles.

This was the first year for SPE ACCE to host a technical session dedicated to additive manufacturing and 3D printing. Ellen Lee, materials and manufacturing research for Ford (Dearborn, MI, US), said that while additive manufacturing isn’t new for the automaker (almost 30 years of experience), the company is focused on going beyond the prototype level to the direct production of end use, functional parts. But Lee said that one of the main challenges of additive manufacturing for automotive is limited materials as many materials currently available are not suitable for automotive applications. “The future direction for us is materials development and understanding how we can customize them,” she said. Ford is also pushing for multi-material printing in a single step. “It’s nice to see automotive embrace additive manufacturing, since our requirements are more unique than medical and aerospace,” she said. “We believe additive manufacturing will significantly impact automotive manufacturing and Ford wants to be involved and also help direct where it goes.”

All of the papers and presentations described here are freely available on SPE’s Web site, at http://speautomotive.com/SPE_CD/SPEA2015/about.htm . Archived papers from previous years can be obtained at http://speautomotive.com/aca.

The keynoter lineup was impressive as well. Ford’s Dr. Deborah Mielewski, senior technical leader for plastics and materials sustainability in Ford’s Materials and Manufacturing Research Dept. (Dearborn, MI, US), is passionate about sustainable manufacturing, and using renewable materials in auto manufacturing. She quipped that her 29 years at Ford feels “like 29 minutes” because she’s enjoyed it so much. She pointed out the challenges of incorporating natural fiber/renewables in automobiles: appearance, survivability in the harsh environment of a car interior, their compatibility (or lack thereof) with polymers, sensitivity to humidity and moisture, degradation during manufacturing and the lack of infrastructure around recyclate streams —making them costly and often hard to obtain. She cited several success stories, including making a soy foam for use in Ford car seat cushions and backs, as well as head rests and headliners. Her group is working with Weyerhauser on an injection-molded cellulose-reinforced center console part for the Lincoln MKX, and has renewable parts on the Ford F150 and Ford Escape. Do sustainable materials sell cars? Probably not, yet, she says, but “We’re protecting the business for future unknowns, and collecting material choices,” pointing out that the next generation of car buyers are very serious about sustainable consumer choices.

BMW’s Stefan Stanglmaier spoke about his company’s production of the i3 and i8 cars, using RTM for “higher geometry” parts together with wet compression molding for simpler part shapes. His principal point was that part cost must come down. To accomplish that, better material efficiency (less waste) is a necessity, and that can be accomplished with more tailored designs, with local reinforcements.

On Jan. 9, the US Department of Energy (DoE) created quite the stir when it announced that it will add $70 million to the $189 million already committed to the University of Tennessee’s Institute for Advanced Composites Manufacturing Innovation (IACMI) for composites R&D. During SPE ACCE, Craig Blue, CEO of IACMI, emphasized that IACMI is a “goal-focused” institute and listed off its five year technical goals, which includes: 25% lower carbon fiber reinforced polymer (CFRP) cost, a 50% reduction in CFRP embodied energy and 80% composite recyclability into useful products. Lightweighting was a key topic throughout the presentation and Larry Drzal, IACMI director and director of vehicles technology area at Michigan State University, said that CFRP composites have the greatest weight reduction potential if cost and manufacturing issues can be solved. He took a closer look at IACMI’s technical goals and how it will be achieved. Beyond having a knowledgeable and dedicated professional staff, he said it is important to have an integration of participant teams in the vehicle supply chain (OEM, Tier 1, material suppliers, SME). Another key element: access to facilities for proprietary projects to help move processes forward.

The event’s big panel discussion, moderated by Jan-Anders Månson, a composites entrepreneur and a professor at Ecole Polytechnique Fédérale de Lausanne (EPFL), was as always insightful. Panelists included Dr. Paul Krajewski, director of GM’s Vehicle Systems Research Laboratory; Glade Gunther of Cytec Industrial Material’s (Heanor, Derbyshire, UK) automotive sector; Rainer Kossak of Novelis Inc., an aluminum supplier to Detroit OEMs; Peter Ulintz of the Precision Metalforming Assn. (PMA, Independence, OH, US); Paul Thom of Schuler Inc. (Canton, MI, US); and Hannes Fuchs of Multimatic (Markham, Ontario, Canada), a well-known Tier 1 supplier of both metal and composites — Fuchs is the company’s principal engineer for composites. Månson started the discussion by cautioning the panelists to avoid any one-upsmanship and to focus on the car of the future that meets the upcoming CAFÉ standards: will it be a multi-material approach, or will composites be localized on special models, driven by car size? A few nuggets came out of the lengthy discussion: Gunther made the point that OEMs want a solution that works, and they really don’t care what the material is, as long as the supply chain is there, together with process knowledge on the shop floor. Fuchs commented that OEMs want functionality for the price, and that it’s a matter of working composites into the “high-volume” mindset of the auto industry. The highlight was a discussion of the huge investment represented by presses and machines, and that it might be possible to actually convert steel stamping presses to mold fast-cure composite parts, or to produce presses that are dual use, for metal and for composites. Again, Fuchs noted that there’s “a complete synergy” between metals and composites; yes, a steel part can be stamped in 4 seconds, but a composite part can now be made in 50 seconds, and that composite part represents part consolidation, co-molded fasteners, or other functions that justify that time differential.

The final keynote was delivered by long-time auto composites expert Antony Dodworth, managing director of Bright Light Structures (Peterborough, UK). He described Zenos E10 sports car that his company is involved with, focusing on the chassis tub. The tub is a complex honeycomb-cored structure with carbon face sheets that come from recycled carbon fabric off-cuts and trim waste. Each of the five elements of the tub incorporates intricate deep draws and shapes, made with Huntsman’s VITROX polyurethane resin and an extruded plastic honeycomb devised by Bright Light, with circular, rather than hexagonal cells, which can be cut to any thickness. The tub elements reportedly are quickly layed in the mold, then sprayed with the resin, then thermoformed in a one-shot sub-15 minute cycle. The unique core crushes under pressure, but still maintains adequate performance, says Dodworth. The five pieces are adhesively bonded together, and to a central “spine” made of an aluminum extrusion that helps anchor the mid-positioned engine and forms the attachment point for many other car systems. The relatively inexpensive sports car is popular in the UK, particularly with racing enthusiasts, and about 12 cars are made per month.