Sponsored By

October 23, 2000

14 Min Read
MARKET FOCUS: Automotive Interior/Exterior

blueprintlogo127.gif


Toexamine the state of the automotive market, one must also takeinto account the state of Mother Earth. Car manufacturers areestablishing self-imposed standards to increase the content ofrecycled materials in automobiles. At the same time, they arenot willing to bend on performance or pricing. Barry Wyerman,director of advanced materials engineering for Lear Corp.-a TierOne supplier (with a captive molding operation) to almost everyauto manufacturer on the globe-shared with IMM how this and othertrends in the industry will affect molders in the coming years.

Materials Trends

Unfortunately, says Wyerman, no infrastructure is in placeto make large-scale use of recycled materials fiscally viable."One of the real issues is that there isn't a steady, low-coststream of these materials that would make it economically attractiveto use recycled resin," he explains. "It's almost asituation where everyone talks about recycled materials and theiruse, but no one wants to pay a premium for them." And therelatively low cost of virgin resin is yet another barrier, saysWyerman.

Taking a step in the right ecological direction, Lear is askingits resin suppliers to provide value-priced recycled materials.Wyerman feels it should be the responsibility of the private sector,and not the government, to set up the infrastructure needed torecycle the plastic used in automobiles, but acknowledges thestaggering costs involved.

"The investment is going to be billions of dollars,"he concedes, adding that it will not happen until it makes goodeconomic sense for companies. "The jury is still out as towhether automotive manufacturers will en-act these self-imposedguidelines when they recognize that Tier
Ones can't produce these recycled parts without a cost penalty.Will they pass that burden on
to their consumers? I know they're not going to absorb it themselves,nor would Lear."

focusintro1-2.gif

Figure 1. These prototype IPs offer aftermarket possibilities for molders and options for consumers who grow tired of their vehicles' interiors.


While efforts are being made toreuse plastics, Wyerman points to another trend that's intendedto help the process of shredding cars at the end of their usefullife: resin consolidation, or reducing the number of materialsused. Currently, shredder yards use various methods, such as floatmechanisms, to separate different material types. Homogenizingthe material used in a vehicle would simplify recycling, Wyermanexplains.

This simplification is becoming more important as the percentageof plastic in automobiles increases. "In prior years a vehiclehad about 20 to 25 percent plastic content," he estimates."Now there's probably around 25 to 30 percent nonferrouscontent. A lot of that is being pushed in the industry by theneed for fuel economy and lighter-weight vehicles."

With the end disposal of the car in mind, another trend Wyermansees has designers creating more environmentally friendly products."This philosophy takes into consideration the entire lifecycle cost of the part," he says. "What does it costto produce? Are there environmental effects in its productionor use? Are there environmental impacts in its disposal or reuse,and what are those costs?"

For example, some materials have a low initial cost, but maycarry a penalty at the end of their life because they can't bedisposed of economically. Conversely, a more expensive materialmay cost less in the end. The trick, says Wyerman, is how to captureaccurately all the costs associated with a material from its firstuse to the end of its useful life.

An outgrowth of designing for the environment is design fordisassembly. Wyerman points out that this developing industryphilosophy again forces manufacturers to consider the end lifeof the vehicle. "If there are materials of dissimilar nature,these pieces can be easily separated into appropriate piles andthe materials segregated," he says, offering another wayto simplify the recycling process.

Molding, Tooling Trends

To achieve the low cost, high quality, and low weight requirementsin materials that OEMs demand for their automobiles, simply shootingresin into the mold is not good enough any more, says Jack Palazzolo,advanced product leads manager for Lear. He says the company isalways looking for new and expanded molding processes to makeplastic lighter, stiffer, and more accurate.

For instance, Lear currently molds some instrument panels withgas assist, and is looking to use it more. "Especially inareas where there's high heat [sun] that causes warpage, gas assistis an effective way to get a stiffer product without using morematerial," says Palazzolo. Also, MuCell, the microcellularfoaming technology licensed by Trexel Inc., is another methodthat Lear is actively investigating because of its potential forincreased stiffness with reduced weight.

Two-shot molding offers some appealing cost and time savingsfor Lear as well, says Palazzolo. The company, which already usesit extensively in tail lamps, is now looking to apply two-shotmolding to interior applications as an alternative to overmolding.Although the equipment is more expensive, Palazzolo has foundin a comparative analysis that as much as 25 percent cost andtime savings could be realized by switching processes. One possibleapplication is an instrument panel with a number of air-conditioninggaskets that currently are applied by hand; two-shot molding wouldcomplete the entire IP in one step.

Also under investigation by Lear is coinjection, which woulduse a virgin skin molded over a core of recycled material. Andfor producing a two-tone door trim panel with a single cover withoutadhesives, Lear has developed a low-pressure, two-tone, single-stepinjection molding process.

Plastic used structurally is another growing trend in the crusadeto reduce weight by eliminating some of the steel, says Palazzolo.Lear's current projects include the following:

  • A structural instrument panel (in conjunction with Nova Chemicals) that integrates air-conditioning ducts and is vibration welded with Branson Ultrasonics equipment.

  • A hybrid steering column support bracket (developed with Bayer), in which a piece of stamped steel is overmolded with a glass-filled nylon 6/6.

Common Architecture

A new aftermarket possibility for molders was introduced byLear at the SAE show last March that offers a way to refresh avehicle. Called the Common Architecture Strategy, it allows avariety of different parts to be attached to a common structurein a car. "Whether you're going after a baby boomer marketsegment, or a Gen X or Gen Y market segment, the door panel isdesigned for the same dimensions," says Wyerman.

This flexibility means the same vehicle could be outfittedwith a variety of color, texture, and appearance options. Forthe molder, it offers additional opportunities in the middle ofan automobile's life, instead of just the beginning. For instance,if the Gen Y consumer grows tired of her orange interior (Figure1, top) after five years, she may wish to replace it with theluxury instrument panel. The one pictured (Figure 1, bottom) isa prototype covered in leather that was sewn and glued on. Inthe future, Palazzolo says the leather may be placed in the tooland molded with the instrument panel in one step, instead of vacuumformed.

No matter the trend, automotive companies have very high expectationsfor their parts, says Wyerman, and that's what drives the needto look ahead. "I don't think the plastic car of today hasnear the negative that it might have had 10 or 20 years ago,"he says. "Now it's an engineered plastic car. Still, OEMsare not willing to compromise performance in these plastic partsthat can replace traditional materials."

Statically Dissipative PP GroundsCharges


focuslnp.gif

A new material on a fuel fillertube housing enabled DaimlerChrysler to cut costs on its JeepWrangler by eliminating an extra component. Originally, the tuberequired a stainless steel strap on the underside of the vehicleto ground electrostatic discharges during fueling. This strapwas eliminated when a statically dissipative polypropylene composite,Stat-Kon M1-HI UV from LNP, was selected for the housing.

As an exterior component, the part has to withstand UV exposurewithout fading and provide adequate impact strength to keep thehousing attached to the vehicle. Another factor, appearance, wassatisfied by the compound thanks to its softer, less shiny finish.Blue Water Plastics in Lexington, MI is the molder.

LNP Engineering Plastics Inc.
Exton, PA
Phone: (610) 363-4500
Fax: (610) 363-4749;
Web: www.lnp.com

PC/PT GIVES STRENGTH, STRUCTURETO BUMPERS


focusgevan1.gif

Following the trend to use moreplastic in structural applications, DaimlerChrysler included arear bumper beam made of a PC/PBT blend in its next-generation2001 Chrysler and Dodge minivans. The beam reportedly exceedsthe 2.5-mph federal impact standard and is molded by Nascote IndustriesInc. in Nashville, IL.

GE Plastics provided the Xenoy1103 resin for the bumper beam. Mark White, market developmentmanager for the material supplier, says the part replaced a moretraditional component comprised of a steel or aluminum beam andimpact-absorbing foam. "This single-piece, injection moldedsystem will be the first nonmetallic, nonglass matte-technology-basedrear bumper to appear on a 4650-lb vehicle in the minivan class,"he adds.

The replacement reduced the part's weight by 8 lb (41 percent)to 11.4 lb. GE sources say Xenoy's strength matches that of bothamorphous and crystalline materials, and it has a high flexuralmodulus, high tensile strength, good chemical resistance, andgood low-temperature impact-all of which were key to maintainingthe bumper beam's structural integrity.

Ford also made use of Xenoy PC/PBT in its 2001 Explorer SportTrac. The rear step-bumper system is a hybrid steel and thermoplasticcomponent, which reduces overall weight. "Design advances. . . significantly lowered Ford's time and investment costs fortooling construction compared to what they traditionally wouldspend for conventional stamped steel bumpers," comments JohnMadej, global automotive marketing director, auto front and rearsystems, at GE. "The two material constructions were developedto work together, thus minimizing material and design redundancy."

Designed for outdoor enthusiasts, the five-passenger SUV incorporatesa cargo bed and step-bumper system that passes the 4 km/hr barrierand pendulum impact test without damage to the vehicle or thebumper system. It provides adequate rigid support for step loadingand is capable of Class II towing, according to GE.

The entire component consists of a PC/PBT impact beam, a molded-in-colorTPO outer soft cover, replaceable TPO step pads, steel attachmentbrackets, and a steel hitch plate. The system is provided to theFord Louisville Assembly plant by molder Plastech Engineered Products(Detroit, MI) as a complete subassembled module.

GE Plastics,
Pittsfield, MA
Phone: (800) 845-0600
Web: www.geplastics.com

PTE replaces PVC in armrest


focusmultibasel.gif

With automotive industryrequirements demanding a PVC-free interior, Honda chose a thermoplasticelastomer (TPE) for the armrest (pictured) of the 2001 model Civicto replace polyvinyl chloride. Multibase's Multi-Flex TPE MR wasselected for its good surface appearance and scratch resistance.Also, tooling changes proved minimal when converting from PVC,and color can be molded in without additional treatment or painting.Springfield Product Industries in Springfield, KY molded the armrest.

A material in the same family is being used in airbag coversin some Suzuki models. Like the Honda armrest, the 90 Shore AMulti-Flex A 9002 MR TPE was chosen for its mar resistance, andalso offers good mechanical properties, processibility, heat resistance,and UV resistance, say Multibase sources. Flow characteristicsof the material have been specially designed to overcome the surfacedefects often encountered because of the internal design of theairbag cover.

Multibase Inc.
Copley, OH
Phone: (800) 343-5626
Fax: (330) 666-7419
Web: www.multibase.com
E-mail: [email protected]

POLYOLEFINS GIVE A NEW CAR A CLASSICLOOK

focussolvay1.gif
focussolvay2.gifRecenttechnological advances have been applied to the 2001 ChryslerPT Cruiser bumper fascia and grille to give the vehicle a retroappearance. Molded by the Decoplas division of Magna Internationalat its facility in Cuautitlán, Mexico, the front and rearbumper fascia are reportedly the first molded-in-color metallic,partially painted, thin-wall applications in the automotive industry.To evoke the chromed steel bumpers of pre-WWI cars, the fasciaare molded of a gray metallic engineered polyolefin from SolvayEngineered Polymers that incorporates a proprietary metal-flaketechnology. Sequel 1440, the polyolefin chosen, contains a UVstabilizer package to protect the unpainted portion of the fascia.The upper front grille, a separate painted component, is alsomolded with Sequel 1440, but does not require the UV package.With a flex modulus of 190,000 psi and the ability to moldparts with a nominal wall thickness of 2.7 mm, the polyolefinenabled project designers to consolidate parts and save weight.A melt flow rate of 18 to 22 g/10 min allowed the material tofill a mold that combines the bumper cover with the lower grilleopening, say Solvay sources.For the vehicle's cowl grille, located at the base of the windshield,Sequel 1733 engineered polyolefin was picked for its low coefficientof linear thermal expansion. The grille, which provides an outletfor airflow from the engine compartment, must maintain an adequateseal with the windshield glass; therefore, the material's abilityto resist distortion was another factor in its selection.Solvay Engineered Polymers Inc.
Auburn Hills, MI
Phone: (248) 391-9500
Fax: (248) 391-9501
Film texturingpossible on
SLA mirror assembly
focusdsm.gifCreating a prototype part for testingbefore the tool is built is not uncommon. However, generatingthe right texture is sometimes important, and can present a challenge.Prototyper Applied Rapid Technologies (Fredericksburg, VA) wastasked with making aftermarket rearview mirror assemblies withadvanced electronic capabilities. Made of DSM Somos 9120 stereolithography(SLA) resin, the three-part prototype-rear, middle, and bezel-hasproperties similar to polypropylene that give it the look andfeel of a production part, say ART sources.A special texturing requirement from the customer that requestedthe mirror prototype-different from standard gloss, matte, ororange peel options typically applied by airbrush-involved applyinga blue photopolymer film on the surface of the SLA part. The 9120resin accepted the texturing to a depth of .0015 inch, says LeeEisinger, president of Akron Metal Etching Co. (Akron, OH), whichperformed the secondary step.In its noninvasive process, AME follows the texture applicationwith blending of seams and splices to remove any pattern anomalies.Next, the parts are exposed to UV-light-curing cycles. The filmis then removed and the part is placed in a chemical bath, whichetches away any unexposed polymer. This results in the texturebuilt up in relief. Thickness varies from .0005 to .012 inch."Paramount to applying a texture," Eisinger explains,"is knowing the actual pattern and depth desired before starting,and then determining if the pattern will stick and stay on thesurface." He adds that the pattern can be removed duringthe experimentation process without destroying the parts.DSM Somos
New Castle, DE
Phone: (302) 328-5435
Fax: (302) 328-5693
Web: www.dsmsomos.com
E-mail:[email protected]

TOOLING,PPS MAKE RELIABLE BRAKE PISTON
focusphillips.gifZeroflash on an anti-lock braking system (ABS) piston means the differencebetween safely stopping and locked brakes on a slick road. Thepart, just larger than a plastic soda bottle cap, includes a grooveabout 14 inch from the top that receives a rubber O ring. TimothyD. Holmes, director of engineering for the molder, GW Plasticsin Bethel, VT, says the part's zero flash requirement proved particularlychallenging."Even a sliver of material fromflash could rub against the ring, causing wear or even a cut,breaking the seal the ring should provide," he explains."And the cost-per-piece didn't allow for expensive secondaryoperations to neatly trim off the flash."Add to these stringent requirements atolerance of ±.001 inch for the outside diameter, O-ringgroove diameter, and parting line matchup. This meant the moldcavities, cores, and slides had to be interlocked. To minimizegate vestige, GW Plastics used a valve gate hot runner systemin a 16-cavity mold. Holmes says his company recognized the needto fill the mold from the top of the part, but gate vestige couldnot extend above this top surface."A specific volume of hydraulicfluid has to be maintained within the ABS cylinder and this ispartially controlled by the height of the piston," he says."Any vestige standing above the piston would change thatdimension." GW built the mold, which was sent to the company'stechnology center to optimize the process and perform capabilitystudies after the vestige problem was solved.Originally, the brake piston was madeof aluminum for its strength properties. However, to reduce costs,engineering thermoplastics were targeted as a replacement material.Switching to injection molding eliminated secondary machining,thereby boosting production rates. Still, it was critical thatthe part not have any internal voids or porosity. The materialchosen for its stability and no shrinkage was Ryton BR111 polyphenylenesulfide (PPS) from Phillips Chemical. The pistons are molded ona 170-ton Van Dorn Demag press.Phillips Chemical Co.,
Bartlesville, OK
Phone: (877) 798-6666
Web: www.rytonpps.com

Sign up for the PlasticsToday NewsFeed newsletter.

You May Also Like