The 1st Automotive Weight Reduction Expo (held concurrently with EV JAPAN)
Report2/An exhibition outline on foamed plastics and new plastic molding technologies
Below is a summary of exhibits focusing on the use of plastics, especially foamed plastics, and new molding technologies at the 1st Automotive Weight Reduction Expo held on January 19-21, 2011, (held concurrently with the 2nd EV & HEV Drive System Technology Expo).
The use of foamed plastics is increasing because of their heat insulation, shock absorbing properties (resistance against impact) and sound insulating properties, in addition to being lightweight.
New plastic molding technologies exhibited at the show included a next-generation die-temperature control technology (by Yamashita Electric) that eliminates weld lines or warp, IMP method (by PLAMO) that eliminates voids, and other engineering methods aimed at higher mold accuracy or the use of plastic products including replacement of metal parts.
Please see Report 1 about exhibits focusing on aluminum and other lightweight materials.
Foamed plastics and other materials for weight reduction
JSP exhibited the suggested use of foamed plastics in 17 automobile components to reduce the vehicle's overall weight. Materials included PP, PC (polycarbonate) PS (polystyrene) and biomass-derived materials (automobile doors were exhibited). According to the company, nearly 40% of the exhibited lightweight components have met commercial application.
JSP's door panel is made of biomass-derived material--weighing approximately 9kg per door, 7kg lighter than its steel counterpart, contributing to an approximately 30kg weight reduction per set of four doors.
Air-conditioner duct for Nissan vehicles manufactured by JSP using the super-foam method (duct for tractors shown below)
Components in JSP's suggested applications of using foamed plastics
|Product name||Material||Characteristics and applications|
|P-block||PP||The raw PP material is foamed in the form of beads, then heated and molded into light-weight, high-shock absorption blocks with thermal resistance and insulation properties.|
|Most often found in JSP's suggested applications, such as seat cushions, tool boxes, door mirrors, door pads, headrests and sun-visors.|
|Mira-Polyca board||PC||PC (polycarbonate) is foamed three times larger in volume and formed into ceiling material and tonneau covers having high resistance against heat and cold shock, and high stiffness.|
|Mira-Polyca foam||PC||PC is foamed 12 times larger in volume and formed into parts of high thermal resistance (120°C). The material has nearly the same shock resistance at -30°C as it does at room temperature. Free of dimensional fluctuation in heat-cycle tests between -30°C-80°C. Suggested for use as ceiling EA (energy absorbing) material.|
|HEATPOR GR||AS||HEATPOR GR (AS, acrylonitrile styrene copolymer) is characterized by high-thermal resistance, dimensional accuracy and resistance against chemicals. Suggested for use as the deck board in a passenger car's luggage compartment.|
|Styrodia||PS||PS (polystyrene) is foamed 50 times larger in volume. Lightweight and rigid. Suggested for making floor leveling material in the car's interior.|
|Super-foam||PP||Blow molding (molten resin is injected and, at the same time, gas is blown into the molten resin to form a hollow block) and foaming takes place concurrently to make various parts in a single process. JSP exhibited air-conditioner ducts that were manufactured by this method for Nissan vehicles.|
|Automobile door panel made of biomass-derived material||Biomass||The door panel made from "biomass-derived composite" consists of a foamed plastic core of vegetable origin sandwiched by fiber-reinforced plastics (FRP). The FRP may be unsaturated polyester of vegetable origin, and the fiber may be glass fiber, carbon fiber or vegetable fiber.|
|The door made of biomass-derived material weighs 21kg including the 9.14kg panel, whereas the steel-made door weighs 28kg including the 15.76kg panel. This contributes to 7kg of weight reduction per door, approximately 30kg of weight reduction per set of four doors. The door has the same strength as a steel-made door. The biomass-derived material may account for up to 80% of all materials.|
(Note) Foamed plastic parts are manufactured by mixing or impregnating the foaming agent in the raw resin and then the mixture is heated to create bubbles. The foamed resin is characterized by thermal insulation, shock absorption and other properties as listed below. By changing the amount of foaming agent, the size, shape and rate of bubbles, a broad variety of products can be produced by foam molding (taken from JSP information).
|Lightweight||Foamed plastic is light and can be carried easily. It weighs less than half the weight of an ordinary solid plastic product and has the same level of strength.|
|Heat insulation||The multi-layered bubble structure ensures hot storage, cold storage and water repellent properties.|
|Shock-absorbing||The material absorbs external shock energy and returns to the original form instantly. This shock absorbing property protects the component from damage.|
|Sound insulation||The material absorbs vibrations and blocks sounds at the same time. This gives it good sound insulation and absorption properties.|
Kyoraku exhibited foamed ducts, blow-molded bumper absorbers (EA material) etc.
Daiwabo Progress exhibited rubber sponge products of numerous automotive applications, and "EPT#143" representing a 30% weight reduction from the conventional product.
Foamed blow ducts and blow-molded EA material
|Kyoraku||Blown ducts||The blow-molding method has led to lightweight air-conditioner ducts with high-thermal insulation properties. The blow-up scale and thickness can be changed to meet the customer's requirements (the higher the scale, the higher the heat insulation). The method is used to make ceiling ducts and instrument panel ducts.|
|Bumper absorber (EA material)||Kyoraku exhibited bumper absorbers for pedestrian protection. In the event of a collision with a pedestrian the material absorbs the impact and protects the pedestrian as much as possible. The method is associated with CAE analysis and impact testing for evaluating the component's performance.|
|The conventional steel-made EA material weighs 1,250g compared to the blow-molded counterpart made from general-purpose PP that weighs only 600g. The manufacturing method is used to make bumper absorbers on Suzuki vehicles.|
Lightweight cargo floor lids (deck-boards)
|Kyoraku||FLP Light||FLP (Fabric-laminated plastic) refers to the integral blow-molding process of the skin and the component and saves the trouble of the post-blow skin laminating process. Thermoplastic skins and resins are used for recycling purposes. FLP is used frequently in the deck-board of the luggage compartment in passenger cars.|
|FLP Light is the same as the FLP process with the addition of a thin-wall molding of the face and back base materials concurrently with the insertion of core material in the hollow part. This enhanced process achieves both weight reduction (40% reduction from the blow FLP process) and high stiffness at the same time that was impossible with the conventional blow process. Its development has been completed.|
|FLP Light S||This further enhanced process is a thin-wall blow molding process that uses thin, face and back base materials. Kyoraku's deck-board, made by this method, has achieved the most weight reduction along with greater freedom of design that was not possible with conventional processes. The finished product looks nicer as well (the process is meant for lighter loads than the FLP Light process).|
Rubber sponge by Daiwabo Progress
|Daiwabo Progress||Rubber sponge||The rubber sponge produced by Daiwabo Progress has an independent bubble structure (bubbles are unconnected to and separated from each other by walls), is water preventive and airtight, sound insulating and easily workable (punching etc). Made from EPDM (Ethylene Propylene Methylene Linkage) etc.|
|Rubber sponge has excellent sealing and water-repellent properties. It is used widely as door interior sealing, lamp packing, electronic-parts packing, and material for making many other automotive parts (also used to make wet suits).|
|EPT#143||EPT#143 is an evolved form of rubber foaming process. The EPDM-based rubber sponge is characterized by a lower specific gravity and soft feel to the touch, and is 30% lighter than the conventional material.|
Weight reducing and fuel saving technologies by Roechling of Germany (exhibited by Starlite)
Starlite introduced new technologies developed by Roechling, a German corporation, and their applications in European vehicles, such as lightweight underbody shield and Jectbonding, a new technology that realizes the integral molding of bracketed pipe components. Also introduced was the lightweight intake manifolds and other components produced by new technologies.
Roechling's Jectbonding technology that realizes blow molding and injection molding in a single shot.
Lightweight intake manifold developed by Roechling
Weight reducing technologies by Roechling of Germany
Lightweight underbody shield
|Starlite||Underbody shield||Roechling, a German corporation partnered with Starlite, has developed underbody shields using fiber-reinforced plastics (GMT: Glassmat-reinforced thermoplastics, referred to as Seeberlite by tradename) based on lightweight and sound insulating PP. The new component is 20% larger in size, 40% lighter in weight, and has better sound insulation and aerodynamic characteristics, than the conventional counterpart.|
|Molding was performed in several areas according to the required characteristics such as hard areas, soft areas and areas that were blown up to increase sound insulation and stiffness. Aluminum foil was used above the exhaust pipe to increase thermal resistance.|
|Used in BMW 5 Series, Volvo S60 etc. The side underbody shield (covering both sides under the car's floor) of the BMW 5 Series weighs 1,230g (made by Seeberlite process), realizing a 550g weight reduction from the conventional PP-made counterpart that weighs 1,780g.|
Blow molding and injection molding completed in a single setting by "Jectbonding"
|Starlite||Jectbonding||This process forms bracketed pipes in a single setting whereas the conventional method requires two settings, the blow molding of the pipe and the injection molding (see note) of the bracket, that need to be welded together. The old method often results in poor bonding between separate parts. Roechling has developed a new technology that takes care of blow molding of the pipe, injection molding of the bracket and welding in the same mold cavity in a near-concurrent style.|
|By using heat-resisting resins, the process may be used to replace aluminum-made ducts. The world's first application of the process, VW Tiguan, has achieved a 30% weight reduction and a 25% cost reduction from the conventional aluminum-made ducts.|
(Note) Injection molding is a manufacturing process in which a molten resin is injected in the molding cavity where it is cooled and hardens.
Weight reduction of air intake manifolds
|Starlite||Material replacement of air intake manifold||Roechling suggests making air intake manifolds from glass fiber-reinforced polypropylene (PP + GF35) in place of the conventional glass fiber-reinforced polyamide 6 (PA6 + GF30). When the change is made, the material's density (gr/cm3) will decrease from 1.35 to 1.18 resulting in a 12% weight reduction and a 15% cost reduction including the material and manufacturing costs. The change will also lead to better sound insulation and higher resistance against chemicals.|
|Air intake manifold integrated with water-cooled intercooler||The air intake manifold developed jointly by Roechling and VW for VW's TSI 1400cc engine (see note). The water-cooled intercooler (designed to cool the hot air resulting from the compression of the turbocharger) is integrated with the air intake manifold to achieve more than a 50% reduction of the intake system's volumetric capacity. This not only corrects turbo lag and improves the response, but it also contributes to 20% reduction each in cost, parts count and weight.|
|The idea that led to the suggested change faced a number of technical problems at first, such as the bonded integrity between the resin-made air intake manifold and aluminum-made intercooler, and an accommodation of changes in the intake air and cooling water (such as flow, temperature, and pressure). The problems were eventually solved by Roechling's resin molding and simulation techniques.|
(Note) The engine is a modified version of VW's TSI 1400cc twin-turbocharged (turbocharger + supercharger) engine (modified to a more fuel efficient engine at the moderate cost of maximum power output). It has a single charger (turbocharger) and the air-cooled intercooler was changed to a water-cooled type to achieve a significant reduction in the volumetric capacity of the air intake system (the air-cooled type had to be placed in the vehicle's front and thus makes size reduction of the air intake system impossible).
New resin molding techniques proposed for improved accuracy and weight reduction
Matsumoto Yushi-Seiyaku exhibited thermo-expandable microcapsules that grow 50 to 100 times in volume and have unique characteristics including being lightweight and heat insulating. The microcapsules have been used in various industrial fields and the company is in the process of developing use for automotive industries as well.
Yamashita Electric exhibited a next-generation die temperature control technology, "YHeaT" based on small-diameter heaters, designed to eliminate weld lines that look like scars, and warp.
PLAMO introduced IMP method that eliminates voids (air bubbles). Products containing voids have been tolerated in many applications (according to PLAMO's information). The company claims that the new IMP method makes molded resin parts of higher strength and will encourage replacement of metal parts with plastic counterparts.
RP TOPLA introduced the "bent pipe injection molding" method-where a floating core (plastic or metal ball) is driven by gas pressure-for applications on VW and other European vehicles.
Coolant pipe for VW made by RP TOPLA's Floating Core Molding technology
New resin molding technologies proposed for improved accuracy and weight reduction
|Matsumoto Yushi-Seiyaku||Thermo- expandable microcapsule||Thermo-expandable microcapsule has a shell made of a thermoplastic high molecular-weight compound and the shell contains a liquefied hydrocarbon (the thermoplastic material softens when heated and forms a necessary shape). The capsule has the average particle size of 5-50μm. When heated, it expands 50 to 100 times larger in size and exhibits light weight, heat resistance and other unique properties.|
|A broad range of thermo-expandable capsules are available to suit specific need with expanding temperature ranging from low (approx. 80-100°C) to high (260-300°C) degrees.|
|Blow molding of engineering plastics such as PC, PBT and PA (nylon) was considered impossible, but a new technology has been developed to make the micro-foaming possible. The F-2800 series capsules of molding-grade engineered plastics have outstanding expanding properties that contribute to up to 30% weight reduction by injection molding and up to 60% weight reduction by extrusion molding.|
|Yamashita Electric||Next-generation die temperature control technology "YHeaT"||The number of molten resin injection gates is sometimes increased to form thin and lightweight parts. But this is often associated with a drawback known as weld marks occurring where the melt fronts converge. This problem can be removed by increasing the temperature but additional time is needed for cooling and ejecting the parts.|
|To solve the time problem, small-diameter heaters are located near the surface of the molten resin in combination with quick-cooling pipes. The temperature control system called the "next-generation die temperature control technology" is designed to raise and lower the temperature quickly within a molding cycle.|
|The temperature control also solves another problem of warp caused by the thickness fluctuation of the material. This is accomplished by applying different temperatures to different sections as needed (low temperature is applied to thick sections to suppress shrinkage and high temperature to thin sections to maximize shrinkage).|
|This method is used to produce car navigation displays for Lexus-brand cars. The company is receiving inquiries about this technology for application on electric vehicles where weight reduction is a major issue.|
(Note) YHeaT stands for Yamashita Heat Technology. Use of this technology in mass production includes thin, lightweight cases for laptops, cases for cellular phone battery packs, camera barrel components, etc.
|PLAMO||IMP method for void control||Developed to eliminate the "void" problem associated with injection molding of plastic materials (often referred to as "bubbles" that are basically a vacuum, though may contain a certain amount of gas). The void causes differences in strength but has been tolerated. It is now drawing close attention amid today's growing need for further weight reduction and higher strength. When the problem is solved as intended, the new method will encourage replacement from the conventional metal to plastic parts.|
|In the IMP (In-mold pressing) method, the resin is injected with the die shut by high pressure. The spacer (the moveable part contained in the die) is removed from the die and the portion where the spacer was is re-clamped (compressed). This method may be used to make thick parts, parts with varying thickness distribution or products of various shapes in high accuracy without voids. The die fabrication generally costs 30% more compared to conventional methods.|
|IMM method||The company is developing a new method called IMM (In-Mold Moving) that will eliminate "weld lines" or "jetting" (meandering marks found on the surface of molded parts) that cannot be eliminated by the IMP method. The new method will control the material flow rate and use higher material and die temperatures.|
|RP TOPLA||Bent pipe injection molding method RFM||RFM stands for "RP TOPLA Floating Core Molding" in which a floating core (plastic or metal ball) is driven by compressed gas to extrude the molten resin in the center area, thereby creating a bending pipe structure 60% lighter than the conventional metallic structure.|
|Conventionally, pressurized air is blown into the die when the resin starts to harden from outside and the air blows away the soft resin in the center area to form a hollow structure. The RFM method allows precise control of the ball's movement and this allows accurate control of the internal diameter and wall thickness.|
|The process uses Asahi Kasei Chemicals' "polyamide 66" with 33% glass-fiber reinforcement. In Japan, the process is used to make the coolant pipe on Yamaha's motorcycles and has achieved a weight reduction from 400g (steel-made pipe) to 165g. Overseas, part manufacturers having a licensing agreement with RP TOPLA are making coolant pipes for BMW, Audi and VW vehicles as well as cowl grills on Ford vehicles.|
Laser sintering technology enhances freedom of design and contributes to weight reduction
NTT Data Engineering Systems exhibited EOSINT/FORMIGA, a set of manufacturing systems based on laser sintering technology which is one of the additive fabrication techniques.
Koiwai makes sand molds using EOSINT-S, one of the above-cited systems. The company exhibited front suspension frames made by integral casting of thin-wall structures achieving a 44% weight reduction compared to conventional products.
Koiwai's front suspension frame made by integral casting using 3D layered sand molds that achieves a 44% weight reduction
Laser Sintering (an additive fabrication method) increases freedom of design
|NTT Data Engineering Systems (Materialise Japan)||Additive fabrication method||Additive fabrication, often referred to as 3D print, is designed for fabrication of parts having complex configurations that cannot be reproduced by conventional methods. A laser is aimed at plastic, metal, casting sand or other powder materials until they are molten and then hardened. This tool-less method increases the freedom of design and contributes to weight reduction, increased strength, cost reduction and short delivery time of products.|
|The method is based on laser sintering, one of the additive (layered) fabrication processes. It takes 3D data created by 3D CAD, etc, slices the data layer by layer, and irradiates laser beams according to the layered data. The powder material hardens as a layer and the process is repeated until the stacked layers form the required three-dimensional configuration.|
|This method is not suitable for mass production as it takes several hours to several tens of hours to make a mold. Hence, it is used to make prototypes or to produce aircraft parts or other parts in limited quantities.|
|The idea and basic technologies of the process were invented in Japan and manufacturing systems called EOSINT and FORMIGA were developed by EOS, a German corporation. The systems are marketed in Japan by NTT Data Engineering Systems acting as a sole agency and Materialise Japan provides technical support.|
|KOIWAI||Use of EOSINT-S system||Koiwai specialized in the fabrication and sales of sand mold prototypes and mass production parts. The company uses EOSINT-S (a sand mold fabrication system) supplied by NTT Data Engineering Systems to make prototypes for automakers and part suppliers.|
|EOSINT-S makes sand molds directly from 3D data without using wood molds or metallic dies. This enables integral forming of sand molds having complex configurations and reduces the number of sand molds per model while enhancing the accuracy of assembly. It also achieves significant saving in time and cost compared to conventional processes.|
|Front suspension frame||Koiwai exhibited a front suspension frame made by an integral thin-wall casting process using a 3D layered sand mold. Integral casting is not possible under conventional processes and several parts must be made using extrusion tools and then welded together. The new process has achieved a 44% weight reduction compared to parts made by conventional processes.|