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November 28, 1999

12 Min Read
Market Focus:  Automotive applications

Table 1.Motor vehicle markets for injection molded plastics by vehicle type (million lb) 

 Light vehicles






 Medium/heavy trucks, vans






Table 2. Motor vehicle markets for injection molded plastics by application (million lb)







 Engine & mechanical












 Battery cases






Market Totals






 Data are courtesy of The Freedonia Group, Cleveland, OH.

Molders and moldmakersserving this, the largest market, must feel besieged by contradictions.On one hand, cars, trucks, minivans, and sport utility vehiclesare flying out of dealerships at a record pace, expected to top16 million units by year's end. The big three automakers-GM, DaimlerChrysler,and Ford-are enjoying one the best sales years in history.

On the other hand, supply chains on the manufacturing sideare undergoing dramatic renovations, putting the squeeze on theinjection molding community. The bottom line is that, despitethe record car sales, molders and moldmakers serving the automotivemarket can look forward to only modest gains over the next fewyears.

The automotive industry is awash with statistics and data characterizingthe state of the market. Picking and choosing indicators can bedicey. Agostino von Hassell of The Repton Group writes the IMMMolders Economic Index and reports that for 1999, the actual outputgrowth for automotive molders on a value basis is less than 2.4percent.

The Freedonia Group's just-published report on injection moldingsays that, irrespective of value, demand for molded plastics inmotor vehicle applications will increase 3.6 percent annuallythrough 2003 (see Table 1). Most promising, it says, are interiorapplications, including instrument panels, knee bolsters, armrests,consoles, gear shift handles, and trim parts. Demand for materialsin such applications is expected to increase 3.8 percent annuallyto 760 million lb in 2003 (see Table 2).

Underhood components-manifolds, valve covers, pulleys, waterpumps, fuel valves, engine covers, impellers, and battery trays-arenot expected to experience the same growth, but will be stimulatedby efforts to boost fuel economy, lower maintenance, and increasequality. Overall, in the decade from 1998 to 2008, the averageamount of injection molded plastic per vehicle is expected toincrease from 108 lb to 132 lb.

In terms of material, PP, nylon, and ABS/SAN account for 74percent of all resins used in automotive injection molding applications.Nylon has the best prospects among the three, increasing in use5.5 percent each year to almost 425 million lb in 2003. Likelyapplications will be underhood in air cleaners, radiator end tanks,oil pans, and fluid reservoirs.

PP and ABS/SAN will experience more modest growth, but willfind continued use primarily inside the vehicle. Bringing up therear with good growth prospects is PC, which is expected to growalmost 5 percent annually to 190 million lb by 2003. Uses includelenses, headlamps, lamp housings, bumper beams, and decorativeparts.



Polypropylene holds tools, endures elements


JacobsonPlastics in Long Beach, CA molds the Tailbox Storage System, whichis designed for use in trucks, minivans, and sport utility vehiclesto store a variety of equipment, including sporting goods, jumpercables, and tools. Departing from traditional aluminum storagesystems, the Tailbox had to be lightweight, durable, and weatherable.

"This product is usually stored in the back of a flatbedtruck, so it must endure the effects of nature's elements,"says Jeff Jacobson, president of Jacobson Plastics. "Furthermore,the Tailbox Storage System must withstand abuse from sportsmen,construction workers, and others."

The material selected as best suited to tolerate all of thisabuse is Hivalloy, a 30 percent glass-reinforced polypropylenealloy from Montell. The PP also reportedly holds its originalcolor well, resists warping during the injection molding process,and has been proven durable in tests conducted by Jacobson.

For more information:
Montell North America
Wilmington, DE
Phone: (302) 996-6000
Fax: (302) 996-6051
Web: www.montell.com



Two-material exterior cover fills the gap


AfterDaimlerChrysler redesigned the Neon for the 2000 model year, injectionmolder OEM/Erie was asked to produce a cover to go over the sheetmetal between the window glass run channel and the door frame.It had to be aesthetically pleasing, provide a seal to reduceunwanted sounds, deter water and dirt, and have a life span ofat least 100,000 miles.

Providing the solution is a part that covers the C pillar.It uses Centrex ASA and Texin thermoplastic polyurethane (TPE),both from Bayer, in a two-shot process.

"We had tough criteria from a design standpoint,"says Greg Wasek, release engineer, small car platform, for DaimlerChrysler."The part had to fit line-to-line with the sheet metal andthe glass run channel. Because it was a very snug fit, we feltthe part needed a gasket on the back. We got together with OEM/Erieand Bayer and came up with the Texin application. When we weretesting the prototypes, all of them fit beautifully."

The ASA is the substrate for the part and comprises the exteriorsurface, which has a black, grained finish. The TPU, also black,is molded onto the back of the ASA substrate and acts as a built-ingasket that provides a good seal and eliminates rattling, buzzing,or squeaking that can sometimes occur.

The ASA is molded first in one machine, with the TPU overmoldednext in another tool and press. The part then goes to a stud fixturemachine, which inserts three metal studs into the back of thepart. The part has reportedly passed DaimlerChrysler's peel testto make sure the TPU stays bonded to the ASA, and the studs passedthe company's 90-lb pull test.

For more information:
Bayer Corp.
Pittsburgh, PA
Phone: (800) 622-6004
Fax: (412) 777-4889
Web: www.bayer.com/polymers-usa



Safety clip, ashtray benefit from aliphatic polyketones


Injectionmolder Foggini, in Rochefort sur Mer, France, makes this headrestsafety clip and ashtray mechanism using aliphatic polyketones,which helped consolidate materials, reducing assembly costs andincreasing production efficiency.

The safety clip is being installed on the front seats of severalcars, including all new Renault Laguna vehicles. The materialchosen for the part, Carilon aliphatic polyketone from Shell Chemicals,demonstrated the high strength and good resilience the part required.Testing showed that the material's elongation yield of 25 percentallowed the clip to withstand repeated deformations without failing.

Also important is the material's inherent lubricity, whichcame in handy in the design and development of the ashtray mechanism.Initially, the ashtray mechanism was designed with three separatecomponents molded from glass-reinforced nylon and lubricated polyacetal,the latter used to provide a low coefficient of friction.

The Carilon, it was determined, provided the strength and lubricityrequired. "As a result," says Guy Bertrand, purchasingmanager for Foggini, "our engineers were able to rationalizethe design and reduce the number of components from three to one."The part was subsequently produced in a single mold, eliminatingthe need for assembly. The ashtray mechanism, using 30 percentglass-filled aliphatic polyketone, is used on the Peugeot 806,Citroën Evasion, and Fiat Monospace vehicles.

For more information:
Shell Chemical Co.
Houston, TX
Phone: (888) 227-4566
Web: www.carilon.com



Headlamp seal holds off water with TPE


Theheadlamp seal on the 2000 Neon from DaimlerChrysler helps keepwater out of the lighting system and enhances the product's weatherabilityand durability.

The headlamps are molded by Valeo Sylvania (Dearborn, MI),which specified Santoprene TPE from Advanced Elastomer Systems(AES) for the seal surrounding the headlamp. Pat Woodworth, programmanger at Valeo Sylvania, says the TPE proved an easy materialto process. It also shows good color retention over the life ofthe product.

The TPE's relatively low specific gravity also provides enhanceddimensional stability, which allowed Valeo to use thinner wallsections and tighter tolerances. For the Neon headlamp the Santopreneis applied in an overmolding process, which minimizes assemblyand manufacturing costs.

For more information:
Advanced Elastomer Systems LP
Akron, OH
Phone: (800) 305-8070
Fax: (330) 849-5599
Web: www.aestpe.com



Nylon engine manifold is molded, welded


Aspart of DaimlerChrysler's effort to make the 2000 Neon a quieterand more refined car, the 2.0-liter single overhead cam engineuses a lightweight, glass-fiber-reinforced nylon air intake manifold.The product is molded in three parts that are welded together,a process that is reportedly more cost-effective than the lostcore method.

The manifold is molded from BASF's Ultramid B3WG7 nylon 6 andconsists of a lower, middle, and upper shell. These three componentsare vibration welded to form the complete manifold with plenumand runners.

BASF assisted in the part design and developed sound optimizationtechniques to reduce noise levels and tune the remaining soundto have a more pleasant quality. Design changes included addingribs and changing wall thicknesses at specific locations.

The nylon is said to provide reliable welding characteristicsthat ensure the manifold meets burst pressure requirements atthe weld joints. Montaplast of North America Inc. molds the manifoldsat its Frankfort, KY plant.

For more information
BASF Corp.
Mt. Olive, NJ
Phone: (973) 426-3910
Fax: (973) 426-3912
Web: www.basf.com/plastics



Complex thermoplastic power distribution centerrises to the challenge


DaimlerChrysler,automotive component manufacturer Thomas & Betts (Memphis, TN),and Dow Plastics teamed up to design, engineer, develop, and producethis power distribution center for underhood use in 19991/2 vehicles,believed to be the first ever such application for a USCAR ClassIII environment.

The power distribution center is comprised of five complexcomponents that are layered and assembled to produce the finalproduct. Each component must exhibit exceptional dimensional stabilityand resist warping. Additionally, the part must pass a seriesof rigorous tests that expose it to chemical attack, impact, vibration,and environmental cycling. The tests evaluated several gradesof Dow's Questra crystalline polymers against PA, PPA, PBT, PET,PPS, and PCT.

The primary part of the power distribution center is an open-toppedenclosure comprised of a series of bosses, ribs, and other protrudingcomponents designed to retain connectors and other electricalparts. Snap-fit on top of the enclosure are three thinner layers,each loaded mostly with small holes designed to accommodate connectorsand wiring. Ease of flow for processing and dimensional accuracyfor assembly were a must.

Ultimately the catalyst-aided Questra polymers won out forthe job, proving easier to process in the mold. The part alsosurvived a series of tests that subjected it to thermal shockcycling, salt fog, vibration and mechanical shock, temperaturehumidity cycling, transmission fluid, motor oil, antifreeze, brakefluid, power steering fluid, gasoline, and diesel fluid. The components,circuit boards, and plastic parts of the sample tested displayedno evidence of warping, fractures, cracks, or changes in coloror odor.

For more information:
Dow Plastics
Midland, MI
Phone: (517) 636-1000
Fax: (517) 638-9752
Web: www.dow.com



Polyolefin replaces ABS in roof pillar applications


Thesethree roof pillar covers can be found in the 1999 Dodge Intrepidand Chrysler Concorde, LHS, and 300M sedans, and are the firstparts at DaimlerChrysler that meet the new federal motor vehiclesafety standard for head-impact protection in upper interior components.

Molded by Venture Industries in Detroit, the parts are designedwith integral, energy-absorbing ribs to comply with the standard,as well as to meet customer requirements, including eliminationof secondary attachments; interior heat resistance; buzz, squeak,and rattle concerns; and low system cost.

Venture originally molded the parts out of ABS, but deemedthe material unsuitable in the face of persistent gloss and ribreadthrough problems that required eventual painting of one ofthe pillars. The replacement material not only had to meet existingrequirements, but had to have a shrink rate of .006 inch to workin existing tools made for ABS, while still delivering improvedcolor ratios.

After testing several materials, the company settled on Sequel2300 engineered polyolefin from Solvay Engineered Polymers. Thispolyolefin reportedly matched the shrink rate of the ABS, outperformedABS in impact tests, and provided the required 2.0 gloss levelwith molded-in color. It also increased melt flow by a factorof 13 compared to the ABS, easing molding process parameters andreducing total manufacturing costs.

For more information:
Solvay Engineered Polymers
Auburn Hills, MI
Phone: (248) 391-9500
Fax: (248) 391-9517
Web: www.solvay.com



Acetal eliminates fasteners in park lock


Theelectronic park lock solenoid prevents the ignition from beingturned off unless the transmission is in the park position. Thisparticular device is manufactured by Pontiac Coil Inc. (Clarkston,MI) and has helped reduce assembly costs by eliminating fasteners.

The lock consists of four parts: an override arm, a case consistingof a base and cover, and a disk pressed on the armature pin toengage the override arm. Two snapfits hold the base and covertogether, and another retains the override arm and its positioningspring.

All of the parts are molded of Delrin acetal from DuPont EngineeringPolymers. The material reportedly gives the snapfits the strength,integrity, and lubricity required to eliminate fasteners.

The cover incorporates features that position the arm. Thebase has an integral receptacle shell, a cylindrical feature thatholds the override arm and a boss, snap, and locking tabs fortwist-on installation in the steering column. The snap hook engagesto prevent backward rotation.

Stelrema Corp. in Knox, IN molds these parts from Delrin 500P.The disk for the armature pin is molded from the same grade byRiver City Plastics in Three Rivers, MI. The solenoid in the lockuses a bobbin molded from glass-reinforced Zytel nylon (DuPont)by Plasti-Coil Inc., based in Lake Geneva, WI.

For more information:
DuPont Engineering Polymers
Wilmington, DE
Phone: (800) 441-0575
Fax: (302) 999-2311
Web: www.dupont.com/enggpolymers

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