Lightening the burden on the planet Plastics are taking to automotives, not only to reduce the weight of vehicles but also to improve the fuel economy, reduce emissions and the carbon footprint. More plastic materials alternatives are also being offered to allow for cost and production efficiency. Other benefits are that its high-temperature resistance and intrinsic conductivity allow the bumpers to be painted on-line without the need for a conductive primer. To enable the painting process, Sabic provided CAE-based parts performance prediction and moulding support. Already, the resin has been used in automotive bumpers for more than 20 years in more than 20 million vehicles manufactured in Europe, the US, Japan, South America and China by GM, Ford, Volkswagen, Renault, PSA Peugeot Citroen, BMW, Audi, Land Rover, Mercedes-Benz, Mitsubishi and Nissan.
Plastic replaces steel in bumpers More stringent vehicle emission restrictions are planned in major automotive markets and this is speeding up innovation in the industry. For instance, in the US, new rules mandate that by 2016, vehicles must get an average of 35.5 miles per gallon. In Europe, mandatory reductions of CO 2 emissions aim to reach 130g CO 2 /km in 2015 for the average new car fleet and 95g/km by 2020.
Plastics open up new era in vehicle glazing Another area where plastics are increasingly being applied is in automotive glazing, to reduce the weight of glazing components. The pressure to reduce vehicle emissions is increasing worldwide, requiring automotive makers to implement weight-out solutions that can also meet rising demand for quality and durability. Exatec, a wholly owned subsidiary of Sabic, and massproduction vacuum technology provider ULVAC are collaborating to accelerate the high-volume production of weatherable, scratch-resistant, plasma-coated Lexan
Plastic bumpers in Mitsubishi Motors’s new RVR compact crossover have reduced the weight of the vehicle
It is for this reason that automotive makers are seeking out alternative materials to make vehicles lighter. Japanbased Mitsubishi Motors’s new RVR compact crossover is the latest vehicle to feature front bumpers made from Sabic Innovative Plastics’s Noryl GTX resin. Mitsubishi also developed front bumpers from the resin for the Delica D:5 minivan in 2007. By replacing steel with this resin, Mitsubishi slashed the weight of the vehicle by 50% or by 3 kg. The ASX vehicle will be introduced into the European market this year and in other parts of the world later. Noryl GTX has been audited by GreenOrder, an environmental strategy firm, which says if all European cars had bumpers made from the resin, savings of 530 million l of fuel and 1.3 million tonnes of carbon dioxide emissions could be realised. By injection moulding it, Mitsubishi designers were able to create a complex bumper geometry featuring a sharp front edge and a side slot for an indicator lamp, which would have been difficult to fabricate in steel as it would require multiple steps and tools. Furthermore, its enhanced flexibility is expected to provide improved head impact absorption in pedestrian incidents as well as recovery of the bumper from minor collisions.
Sabic recently introduced new scratch and abrasion evaluation capabilities – including new methods and processes – to evaluate the effects of surface wear on PC glazing using either wet coat or both wet coat and plasma coating technologies
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AUTOMOTIVE PC resin for vehicle windows. Under the agreement, ULVAC w i l l m a n u f a c ture turnkey m as s p roduct ion systems that leverage its expertise in high-volume vacuum equipment and Exatec’s proprietary plasma coating technology. The combined ULVAC and Exatec expertise will help automotive makers and OEMs replace heavier glass windows with Lexan resin glazing to meet upcoming regulations for lower CO 2 emissions and also provide d e s i g n f re e d o m a n d c o s t re d u c t i o n t h ro u g h p a r t s consolidation. T h e h a rd c o a t i n g P C t e c h n o l o g y i s a l re a d y i n production and this tie-up for vacuum coating equipment will speed up the process. Sabic says that over the past few years Exatec coatings and Lexan have been used for the glazing on many technology demonstration vehicles from OEMs. ULVAC’s vacuum equipment enables this coating system to be scaled up for production. It allows a high deposition rate, a continuous process and the ability to coat parts with complex shapes and a wide range of sizes, says the company. Automotive makers will soon be able to order machinery from ULVAC.
“Plastic air intake manifolds are used in the majority of vehicles produced worldwide today because of the optimised air flow, design freedom and general reductions in weight and cost they offer over their metal counterparts,” comments Dennis Nicholls, Project Manager at Mahle. “However, rising under-thehood temperatures, demands for improved function integration capability, noise reduction and ever-lighter components, plus the need to reduce our own and our customers’ overall system costs, means we have had to look beyond polyamides to meet these challenges,” he said. Borealis says its material lowers system costs without significant change in tool and part design and provides better acoustic behaviour. To eliminate Mahle’s need for equipment investment, same-speed production with existing injection moulding processes and postmoulding techniques, such as direct screwing, was a key stipulation. The XMOD GB306SAF compound is a high stiffness 35% glass fibre-reinforced PP compound that offers long-term high heat and chemical resistance, vibration resistance combined with high fatigue and a broad operating temperature between -40°C and +120°C. In addition, as a lighter weight, lower density material it enables weight reductions for AIMs of up to 15%, while offering improved sound damping over current acoustic behaviour for AIMs. It also contributes
Reducing production costs Elsewhere, companies are improving production cost-efficiency and achieving both performance and environment-friendly benefits by allowing the use of alternative materials. With PP already a widely used thermoplastic material in cars and under the hood, Borealis offers a glass fibre-reinforced PP compound for air intake manifolds (AIMs). These are manufactured by Mahle Filter Systems UK for Volkswagen (VW) car models. In fact, VW is the first automotive OEM to switch from glass reinforced PA to PP for this underthe-hood application.
Borealis’s glass fibre-reinforced PP compound was used for this air intake manifold that is usually made from nylon
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AUTOMOTIVE BASF conducted an Eco-Efficiency Analysis for a typical automotive application where two intake manifolds with a service life of 200,000 km were compared. It found that the glass fibre-reinforced Ultramid had slightly less environmental impact but considerably higher costs than the traditional PA6. For an air intake manifold, the standard PA6 resin thus represents a more ecologically efficient solution. T h e s e b a c i c a c i d u s e d f o r p ro d u c t i o n o f PA 6 1 0 provides a slight ecological benefit, however this benefit is based not on the plant origin of the carbon, but on the lower specific weight of the resin. The considerably higher additional costs associated with the production plants for this relatively low-volume plastic, however, outweigh the slight ecological benefit from an economic standpoint. A further contributing factor is the volatility of the sebacic acid price, which is typical for renewable resources. It results from the occasionally occurring crop failures and the resultant fluctuations in availability. The plastic is thus of interest today not because of its renewable resource base but for its performance profile, which positions it above PA6 and PA66 and raises it to a level comparable to PA612 and PA12 when it comes to certain central properties
to lowering overall production costs for AIM parts through its lower material price and its lightweight benefits of improved handling and reduced energy usage. Lower processing temperatures and the lack of pre-drying further reduce overall energy consumption and eliminate manufacturing steps, achieving more cost-effective production, says Borealis. Reducing friction and using bio-based materials DuPont Automotive, meanwhile, says that reduced friction can help to reduce fuel consumption. “Six of every 7 l of fuel put into a vehicle are lost to inefficiencies,” said Dave Ritchey, Global Transportation Segment Leader at a seminar in the US recently. “Connecting inefficiencies to friction, studies have found that somewhere around 10% of this lost energy is attributed to friction between moving parts,” he said. DuPont has been studying and developing new products like Vespel SP-2515. Using a basic thrust washer test, DuPont says a 45-55% reduction in friction is possible by using SP-2515 instead of PEEK, even at cold temperatures.
Microcellular process reduces carbon footprint US-based Trexel says its MuCell microcellular foaming process not only improves aesthetics and strength but is also able to reduce the carbon footprint of vehicles. It says that if 100,000 cars feature optimised MuCell component applications, the use of petroleum could be reduced by more than 6.3 million gallons and carbon dioxide emissions reduced by 65,000 tonnes over the course of a 150,000 mile life span. It is for the above reasons that MuCell has ben applied by Tier One suppliers TRW Automotive, ElringKlinger and Inalfa Roof Systems Group for parts produced for Porsche, Volkswagen and Cadillac. Inalfa Roof Systems, a leading provider of vehicle roof systems, used MuCell process to produce a large one-piece frame for the Cadillac CTS sunroof module. Typically sunroof openings for mid-size and large-size cars are multi-part assemblies as dimensional stability and stiffness are difficult to achieve in large one-piece designs. In this sunroof, the front and rear beams and two guides were consolidated into one part measuring 1 m x 1 m. It is also the first integrated sunroof module assembly manufactured using short-glass-filled PP, achieving weight savings of 12% versus a traditional four-piece design. And since the number of tools and checking fixtures were dramatically reduced, the total capital investment required was reduced by nearly 50%, along with a considerable reduction in component cost. Assembly time was also reduced by more than a minute (67 seconds), with a moulding cycle time reduction of 15 seconds.
BASF’s new grades are resistant to salt and hot water
German company BASF , on the other hand, has expanded its PA610 range to include three glass fibrereinforced grades and a blend from PA610 and PA66 to complement the unreinforced Ultramid S3K Balance. The highlight of this grade is that it is 63% castor oilbased plus its hydrolysis and stress crack resistance against chemicals like calcium chloride or zinc chloride, which is used in Asia and Russia as road salt. The three new grades are thus well-suited for overmoulding of metal and electronic components that come into contact with aggressive fluids also for housings and transmission components where dimensional stability is a major factor and for wheel speed sensors, oil filters and oil pans. 3
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AUTOMOTIVE Another company that used the MuCell technology to render savings is TRW Automotive that developed a passenger side front airbag cover, which is free of sink marks. Other benefits are that the air bag cover, which has a complex part geometry, features thin wall sections from 0.4-2.5 mm. The economical benefits are that the production is able to be undertaken on a reduced machine size, by 40%, (300 tonnes instead of 500 tonnes for conventional moulding). Using recycled materials in car parts Germany-based Fraunhofer Institute for Chemical Technology (FICT) has developed a new method for mass producing thermoplastic fibre composite materials for large-scale car production. Once they have reached the end of their useful life, the parts can be shredded, melted down and reused to produce high-quality parts. And they also perform significantly better in crash tests since thermoplastic components reinforced with textile structures absorb the forces generated in a collision through viscoelastic deformation of the matrix material, without splintering. Vehicles used to be predominantly made of steel. However, this raw material has long faced stiff competition from other materials and modern cars are now built from a mixture of steel, aluminium and fibre-reinforced plastics. Highly stressed load-bearing structures and crash components that are designed to buckle on impact help to reinforce the body in order to protect the vehicleâ€˜s occupants in the event of a collision. A u t o m o t i v e m a k e r s h a v e p re v i o u s l y c o n s t r u c t e d p a r t s f ro m composites using a thermoset matrix. But this approach has a number of disadvantages: as well as being difficult to implement efficiently in a mass production environment, it can also be potentially hazardous since this material tends to delaminate into sharp-edged splinters in a collision. A further problem is the fact that thermosets cannot be recycled. Researchers had previously failed to come up with a suitable manufacturing technique for thermoplastic composite structures made from high performance fibres, but FICT has now developed a process suitable for manufacturing up to 100,000 parts/year and a shorter cycle time of 5 minutes compared to thermoset components that require more than 20 minutes. The technique is known as thermoplastic RTM (T-RTM) and is d e r i v e d f ro m t h e c o n v e n t i o n a l RT M ( re s i n t r a n s f e r m o u l d i n g ) t e c h n i q u e f o r t h e r m o s e t f i b re c o m p o s i t e s u s i n g c a r b o n o r g l a s s fibres. The composite is formed in a single step by inserting the pre-heated textile structure into a temperature-controlled moulding tool so that the fibre structures are placed in alignment with the a n t i c i p a t e d s t re s s . T h i s e n a b l e s t h e p ro d u c t i o n o f l i g h t w e i g h t components. The next step involves injecting the activated monomer melt into the moulding chamber with a catalyst and activator system. The ingenious part is that the researchers can select the system and the processing temperature in a way that enables them to set the minimum required processing time. A d e m o n s t r a t i o n p a r t t h a t t h e re s e a rc h e r s h a v e m o d e l l e d i s a trunk liner for the Porsche Carrera 4. Its weight is said to be 50% lower than the original aluminium part. FICT says that the cost of the thermoplastic matrix material and the cost of its processing are also up to 50% lower than the equivalent costs for thermoset structures. U 4 INJECTION MOULDING ASIA â€˘ SEPTEMBER 2010
Injection Moulding Asia Issue September 2010