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REINHARD STRANSKY ET AL.

Even though the growth curve for theautomobile market as a whole hassuffered a clear downturn due to the

current crisis, it is expected that the quan-tity of electronics per car will continue togrow. According to a study by MercerManagement Consulting from 2006 themarket for automobile electrical and elec-tronic systems will grow by nearly 6 % perannum (Fig. 1). In 2007 Roland Berger in

partnership with BASF came to similarconclusions. According to their investi-gation the electrical & electronic share ofvehicle value will be around 30 % by 2015,with one third in electrical and two thirdsin electronic systems. Electronic systemsare also going to increase in the growingsegment for small automobiles, particu-larly where they contribute to improvedsafety. Today the majority of innovationsin vehicles are based on electronic con-trol and the cable loom has now becomealmost the largest single component in acar. Alongside passenger safety and com-fort, reductions in emissions and fuelconsumption are naturally also a central

issue. Here the reliability of componentsis of particular importance. In order tomeet all of these requirements plastic asa material is becoming ever more signif-icant. Its advantage lies in its low weightcombined with excellent freedom of de-sign and the ability to integrate differentfunctions. For this reason the proportionof plastic components in electrical andelectronic systems is growing morestrongly than in other vehicle areas.

Whilst in the sixties a car had electri-cal systems, but practically no electron-ics, today a top of the range automobilecan contain up to 70 electronic controlsystems. According to Bosch the use of

Ever More Electricityand PlasticCurrent Trends. Interest in mechatronic components is growing in the automobile

electrical and electronic sector. At the same time the installation space is shrinking

further and component weights have to be as low as possible. This leads to de-

mand for even thinner wall sections in connectors and sensors as well as growing

requirements for particular material properties. It is principally engineering plas-

tics, such as specially developed polyamides and polybutylene terephthalate, that

are considered to be suitable in this context.

The dual-clutch gear-box controls fromContinental are madeout of a polyamide 66that is particularlyresistant to hot andaggressive gearboxoil

Translated from Kunststoffe 6/2009, pp. 82–86Article as PDF-File at www.kunststoffe-international.com; Document Number: PE110133

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ESC (Electronic Stability Control) for ex-ample has grown continuously over thepast few years. The proportion of new ve-hicles with these active safety systems hasgrown particularly strongly in the NAFTAregion and has now overtaken the pro-portion in Europe. Future growth ratesare still going to be high since ESC is go-ing to be mandatory in the USA for newcars from the model year 2012 onwards.Europe has also tightened up on the reg-ulatory side and announced a mandato-ry requirement for new cars from 2015and for new models as early as 2012.Strong growth for ESC is also predictedin Asia. Figure 2 shows many other de-vices and modules right across the rangeof vehicle electronics that cannot be pro-duced without plastics. These compo-nents can be categorized into the areas of

electronic controls and actuators (e.g. re-lays and motors), plug connectors, sen-sors as well as lighting technology.

The growing interest in mechatroniccomponents is amongst the currenttrends in electrical/electronic systems inautomobiles. At the same time the instal-lation space is shrinking further and com-ponent weights have to be as low as pos-sible. This leads to demand for even thin-ner wall sections in connectors and sen-sors as well as growing requirements forparticular material properties. Hydrolyt-ic stability and laser weldability of plas-tics are examples of these properties. Ontop of this there is the demand for mate-rials that are resistant to calcium chlorideand biofuels and can withstand a largenumber of thermal shock cycles. Themost commonly found classes of materi-

al are therefore polyamide (PA) and poly-butylene terephthalate (PBT).

In this article we will show which newproducts and applications from its Ul-tramid (PA) and Ultradur (PBT) productranges BASF has selected to address thesetrends and challenges.

Mechatronics

Modern compact, integrated mechatron-ic components are different from con-ventional systems in that the functionalgroups of sensors, actuators and intelli-gent electronics are directly mounted onor very near to the mechanical part beingcontrolled. It is only possible to constructsuch highly integrated parts through theuse of high-performance engineeringplastics. Only a freely formable material,a high degree of stiffness and strength, to-gether with chemical and temperature re-sistance can protect the electronics and atthe same time combine the actuators andsensors in very limited space within a sin-gle component. Wiring work, the num-ber of cables and connectors can be dras-tically reduced, interfaces are no longerneeded and the part is small, light and re-liable. Even though the impetus formechatronics originally came from theelectronic and machinery industry, it isthe automobile sector that is the drivingforce today.

Gearbox controls are typical mecha-tronic components that are under con-tinuous development.Ultradur B4300 G6is used in the dual-clutch gearbox con-trol that was introduced by Volkswagenin 2006 and is still in production today.This special PBT is suitable for hot oil re-sistant component groups and is able to

integrate nearly two dozensensors and actuators as wellas the necessary connectiontechnology into a single part.However, in further develop-ing the construction conceptof the control systems for thenext generation of dual-clutchgearboxes, the highly ther-mally stabilized UltramidA3WG6 is being used (Titlepicture). Since gearbox oils aremore aggressive and less stan-dardized than motor oils andat times also very hot, the con-tinuous operation of gearboxcontrol systems represents avery demanding application.In the original as well as thenewest control models thespecific requirements for di-

Air bag control

Engine management

ABS/ESC systems

Air flow sensor

Ignition system

Oil sensorGearbox control

Electronic gas pedal

Wheel sensor

Seat control

Door control

Lighting control

Power assisted steering

Distance control

Driver authorizationsystem

Central control systemand energy distribution

Rain sensor

Information system and navigation

Fig. 2. Electronic devices in automobiles

Chassis

Engine anddrive chain

Body (exterior)

Interior

Electrical andpower supplysystem

5.9 %

Growthper annum

5.9 %

4.9 %

6.0 %

7.0 %

5.5 %

2005

20%Proportion ofelectronicsper vehicle

13013

28.5

19.5

31

38

2015

≥30%

230

23

46

35

61

65

Market Growth

Fig. 1. The worldmarket for automo-bile electrical andelectronic systems is growing at almost6 % (data in billionEUR) (source: Mercer Man-

agement Consulting, 2006)

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mensional stability and chemical resist-ance could be safely met by the materialtypes used.

Exceptional mechatronic componentscan be produced when laser activatablepolymers such as Ultramid T 4381 LDSare used. This polymer contains laser sen-sitive additives. It can therefore be struc-tured and activated with the help of alaser, so that in the steps that follow,metallic conducting tracks can be pre-cisely applied to the three-dimensionalsurface of the plastic component using anelectro-chemical process. Thus withoutPCBs and cabling the plastic componentcan be made into a carrier for electroniccircuitry. Prominent examples of this are3-D MIDs (Molded Interconnected De-vices – injection molded circuit carriers),like the ones manufactured by Germanautomobile or South Korean cell phonesuppliers (Fig. 3). The polymer, which isfrom the Ultramid T LDS range, is a part-ly crystalline, partly aromatic reinforcedPA 6/6T. The high temperature stabilityneeded for lead free soldering (meltingpoint 295°C) and the high heat distortiontemperature under load (265°C at 0.45MPa) are amongst the most important re-quirements for the material. 3-D MIDsare a very innovative example of the abil-ity of the polymer for functional integra-tion. In addition they have a very high po-tential for further miniaturization.

Laser Welding

A joining technique in automobile elec-tronics that is finding growing interest islaser (transmission) welding since it canjoin plastic parts without contact, dustgeneration or mechanical loading. Thusit is not only cleaner than gluing, but al-so prevents potential damage to the elec-

tronics through vibrations, which occurin other techniques. On top of that com-ponents can be particularly reliablysealed by laser welding. During laserwelding a laser transparent componentis joined to a laser absorbing one, wherethe energy is transferred to the absorb-ing part, causing it to melt and form thejoint. Whilst all black standard materialsabsorb laser light to a certain extent thechallenge lies in developing laser trans-parent materials. Laser welding requiresspecial materials that have good and inparticular uniform laser transparency.Alongside the well known black lasertransparent Ultramid A3WG6 LT (PA 66)BASF already offers a particularly suit-able Ultradur grade that guarantees avery high level of process security. Theportfolio of these laser transparent PBTspecial grades is being further expanded

in order to meet future market require-ments [1].

Thin Walls

Smaller and lighter – this trend is leadingto ever thinner component walls in elec-tronic parts. For example in order to pro-duce dimensionally stable and correctlyfilled connectors during the injectionmolding process optimized high flow ma-terials are necessary. The improved flowproperties can however also be used forcomponents with normal wall thickness-es to reduce manufacturing times andthus save costs. Following the success ofthe high flow, reinforced nano-additiveUltradur High Speed grades (Fig. 4) forthe first time a new unreinforced versionhas been included in the range. The newmaterial, Ultradur B4520 High Speed,

Fig. 3. Ultramid T 4381 LDS, a laser structurable polymer, is used in mechatronicparts (left) as well as in polymer aerial chips for cell phones (right)

Fig. 4. The filigree and thin walled polymer housing of the latest steeringangle sensor from Bosch is made out of Ultradur B4300 G4 LS High Speed,a laser markable, 20 % glass-reinforced version of the very high flow PBT

Fig. 5. Quick release couplings for fuel lines from A Raymond made out of high performance UltramidT KR (PA 6/6T)

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that has recently been introduced into themarket combines high flow, stiffness andgood toughness in a completely new way.

In 2008 it was also possible to show thatthe concept can be extended topolyamides with the first Ultramid HighSpeed products. This first product fami-ly has thermal stabilization typical for ap-plications in the engine compartment. Inthe next stage an additional UltramidHigh Speed range is to be introducedshortly. The first product in this range isthe new Ultramid A3EG7 High Speed,

which like its predecessors is a PA66 andwith its very good flow properties offersthe typical High Speed feature. The ben-efit of this feature can be seen in reducedinjection pressure and clamping force, re-liable part filling and a low level of rejects,even with complex geometries. On top ofthis the material offers an additional ad-vantage that is particularly useful for elec-tronic components: A3EG grades have alight self-color and are therefore suitablefor the widest possible range of col-orations at customers.

Hydrolytic and Thermal ShockResistance

The requirements for hydrolytic resist-ance of materials for electrical and elec-tronic components, e.g.housings for con-trol systems, sensors and connectors, at

OEMs worldwide are growing in stepwith the increasing significance of the US-Car Test, an American set of regulationsfor the automobile industry, in other re-gions of the world. On the whole com-ponents made from polyamide do verywell under the USCar Test. However, un-der the conditions of the USCar Testmany PBT grades commonly found in themarket that due to their good dimen-sional stability are popular in the elec-tronics industry, suffer from hydrolyticattack.

During hydrolysis of PBT the poly-condensation reaction that is used to pro-duce it is reversed. The polymer breaksup into short polymer fragments and be-comes brittle. In order to test the hy-drolytic suitability of PBT materials cyclictesting between -40° and +150°C underwet conditions are no longer uncommon.The tests are typically performed follow-ing long term conditioning at 85°C and85 % relative humidity or acceleratedconditioning at 110°C and 100 % rel. hu-midity. Under these conditions two of thenew particularly hydrolytic resistant PBTgrades from BASF, Ultradur B4300 G6HR and Ultradur B4330 G6 HR, performsignificantly better than standard grades.By using these two materials the servicelife of components under ex-treme hydrolytic conditionscan be improved many timesover. In addition UltradurB4330 G6 HR in comparisonto conventional products inthe market offers improvedresistance to alkaline environ-ments. Recently a trend to-wards more stringent thermalshock rather than tempera-ture change tests has beenseen. These are cyclic testswhere the part is taken rapid-ly backwards and forwards be-tween temperature extremes,

BASF SEFachpressestelle KunststoffeD-67056 LudwigshafenGermanyTel. +49 621 60-43348Fax +49 621 60-49497www.plasticsportal.net

Manufactureri

Fig. 6. Ultramid T KR4355 G7, a partly aro-matic polyamide with35 % glass fibers,meets the require-ments of Bosch fortheir tank pressuresensors

for example -40 and +140°C. Since thehydrolytically stable Ultradur B4330 G6HR is particularly tough it offers the re-quired mechanical properties in order toreliably survive such thermal shocks, evenin combination with metal.With the helpof the new Ultradur HR grades the ap-plication spectrum of PBT under unusu-al conditions has been significantlywidened.

Calcium Chloride and BiofuelResistance

Biofuels bring new and challenging re-quirements for electronic housing mate-rials in the fuel supply system. Materialsthat come into contact with modern fu-els now have to be not only resistant togasoline, but also resistant to methanoland ethanol. These substances are main-ly found in the fuel tank due to the addi-tion of alcohol to normal gasoline (bio-fuel). On top of this components of theunderbody can come into contact withthe zinc plated body work where undercertain circumstances through the actionof water spray the salt zinc chloride canbe formed. Components such as quick re-lease couplings for fuel lines (Fig. 5) ortank pressure sensors (Fig. 6) are there-fore made out of Ultramid T, which hashigh temperature stability. However, therequirements for water spray resistanceare also continuously rising. With the in-creasing use of calcium containing grit-ting salt in the USA and Japan the calci-um chloride resistance of polymers hasbecome a topic of discussion. Ultramid Tgrades are also stable in respect of this salt.Unlike polyamide PBT is generically cal-cium chloride resistant.

Metal-Polymer Composites

At the scale at which metal and polymerform a close composite in mechatronic

Fig. 7. Gas tight mechatronic composite parts made out ofmetal and polymer can be manufactured in two steps usingUltramid Seal-Fit in a simple injection molding process

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component parts the sealing of this com-posite has to be ensured. The risk of anincorrect function through contact withmoisture or oil increases in parallel withthe rising number of electronic compo-nents. BASF offers an elegant way to re-duce this risk through the use of Ultra-mid Seal-Fit. This unreinforced trans-parent copolyamide is used to seal con-ductive tracks of electronic componentsby overmolding. It has good adhesion tometal as well as polyamides. Thus it rep-resents an alternative to conventionalconcepts, which are very complex and usesilicone adhesives, hot melts or impreg-nation/pre-coating. From a process tech-nology standpoint it is helpful that Ul-tramid Seal-Fit, just like the classic hous-ing material, can be injection molded.The premolding of the conductive trackswith Ultramid Seal-Fit can therefore bedirectly followed by overmolding with thehousing material. Since the customer al-so uses premolding in the conventionalprocess the housing material is simply

substituted by the more effective sealingmaterial and pre-treatments are no longernecessary (Fig. 7).

Conclusion

In automobiles the critical issues of fuelsaving, environmental protection andsafety are closely linked to the presence ofhigh-performance electronics and mod-ern electronics in their turn require solu-tions for the joining of polymers and met-al. Decisive developments in the sensitivearea of automobile electrical systems andelectronics occur when an understandingof the function of the components isbrought together with in-depth knowl-edge of material properties. This can on-ly be the result of intensive cooperationbetween the component developer and apolymer specialist. The target for the ex-perts in doing this is to combine intelli-gent mechanical design with the reliabletransmission of electrical energy or elec-tronic signals. This means that there is a

great deal of development space for wellestablished as well as innovative materi-als and concepts. ■

REFERENCES

1 Reference should be made to patent number EP-B751 865 in respect of the manufacture of singlecolor components

THE AUTHORS

DIPL.-ING. REINHARD STRANSKY, born in 1956,Project Management Automobile E&E.

DR. ANKA BERNNAT, born in 1968, BusinessManagement Polyamide.

DIPL.-ING. KARL-MICHAEL REINFRANK, born in1960, Management Global Key Accounts E&E.

DIPL.-ING. MARK VÖLKEL, born in 1961, BusinessManagement Ultradur.

DIPL.-ING. VOLKER ZEIHER, born in 1974, Applica-tion Engineering E&E.All of the authors work in the Engineering PlasticsEurope business unit of BASF SE in Ludwigshafen,Germany.Contact: sabine.philipp@basf.com

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