Automotive Weight Reduction Expo 2015

Carbon fiber reinforced thermoplastics and high-tensile steel sheet processing

2015/03/05

Summary

An example of carbon fiber-reinforced thermoplastics use
An example of carbon fiber-reinforced thermoplastics use (exhibited by Ichimura Sangyo)

 The fifth Automotive Weight Reduction Expo and the first Automotive Parts Manufacturing Expo were held in January 2015 as part of the Automotive World 2015 at the Tokyo Big Sight. This report focuses on weight reduction technologies for automotive use that were introduced at the two exhibitions.

 One of the highlights was the engineering technology for Carbon Fiber Reinforced Thermoplastics (CFRTP). Ichimura Sangyo Co., Ltd., one of the Toray group companies, exhibited "stampable" CFRTP and their samples. Asano Co., Ltd. exhibited hybrid molding technologies that used Ichimura Sangyo's CFRTP, resins and metals. Sato Machinery Works Co., Ltd. and Daido Kogyo Co., Ltd. also exhibited their CFRTP processing technologies.

 H-One Co., Ltd. exhibited cold-forging technology using 1470MPa-class ultrahigh -strength stainless steel which is in the company's trial production stage. The company also exhibited technologies for bending pipes in arbitrary 3D shapes during hot-quenching . Kurimoto, Ltd. displayed magnesium alloys that are under development.

 Plastic processing technologies were also exhibited by several manufacturers. Sumitomo Bakelite Co., Ltd. exhibited a new method for molding long-fiber-reinforced thermoplastics. Toyobo Co., Ltd. exhibited foam molding technologies and Ube Industries, Ltd. exhibited polyamide that accepts non-electrolytic plating. Yamashita Electric Co., Ltd. exhibited a molding technology that leaves no weld lines on parts.


Related Reports:

Automotive World 2015 (Feb. 2015):
European OEMs and suppliers plan to launch 48V hybrid systems after 2016
Advanced Driver Assistance Systems (ADAS) by Bosch, Denso and Renesas
EV & HEV Drive System Technology Expo 2015

Automotive World 2014:
EV & HEV Drive System Technology Expo 2014 (Feb. 2014)
Automotive Weight Reduction Expo 2014
   (Part 1): High-strength steel sheets, lightweight metals, and 3D Printing
(Feb. 2014)
   (Part 2): Weight reduction technologies through the use of resin and carbon fiber reinforced plastics (Mar. 2014)



CFRTP processing technologies

Ichimura Sangyo: Stampable CFRTP sheets

Ichimura Sangyo, a Toray group company, sells carbon fiber textiles and composites. The company exhibited its stampable carbon fiber-reinforced thermoplastic prepregs (CF-SS).
CF-SS is a carbon fiber-reinforced stampable sheet that is processed by infrared heating, dissolving, hot press molding and cooling. It is manufactured by Ichimura's affiliated equipment manufacturers and processing companies (including Asano described later) and it takes only approximately a minute to manufacture CF-SS. Sample shipment of CF-SS started in 2014.
A center pillar molded with CF-SS and iron A cross member molded with CF-SS and iron
A center pillar molded with CF-SS and iron. Iron is surface-treated before it is joined with the molten CF-SS. A cross member molded with CF-SS and iron
A seat bracket Decorative molds made of CF-SS
A seat bracket formed by hybrid molding of CF-SS and pellet (ribs) Decorative molds made of CF-SS (smartphone cases) with smooth and glossy surface (bottom) and textured surface (top).

 

Asano Co., Ltd.: CFRTP molding technologies

CFRTP hybrid molding Asano specializes in product development and processing such as trial production of parts and die designing. The company exhibited hybrid molding technology for CFRTP using the material supplied by Ichimura Sangyo. Hybrid molding allows engineers to mold CFRTP over portions that require additional strength. This reduces the use of CFRTP which, in turn reduces production costs.
Asano holds the following innovative CFRTP processing technologies: (1) Simultaneous hybrid processing of CFRTP stamping and injection molding of long-fiber carbon fiber pellets (2) Laminated CFRTP and metal systems CFRTP and other metals have different coefficients of thermal expansion and carbon fibers are highly resistant to expansion. This makes carbon fibers unfit for molding. Asano has challenged this drawback by moving the material during the molding process.
CFRTP high-cycle molding CFRTP is molded in high cycles lasting approximately 60 seconds. The stampable CFRTP sheet is heated in the die for approximately 30 seconds and is cooled after molding.
CFRTP automotive parts Laminated CFRTP and metal system
CFRTP automotive parts formed by hybrid molding such as door mirror parts and seat bracket parts. The same molded parts were exhibited also at Ichimura Sangyo's booth. Laminated CFRTP and metal system formed into a center pillar. The same item was also shown at Ichimura Sangyo's booth.

 

Sato Machinery Works Co., Ltd.: CFRTP hybrid molding machine and pultrusion molding process for thermoplastic composite materials

CFRTP hybrid molding machine Sato Machinery Works, a molding machine manufacturer, has developed a hybrid molding machine that performs CFRTP pressure molding and injection molding at the same time. The company has sold compact molding machines to several automakers for research and development purposes. Sato exhibited molding samples.
Pultrusion molding for thermoplastic composite materials Sato Machinery Works has also developed pultrusion molding processing technologies for forming CFRTP and other thermoplastic materials into pipes and rods. It is currently in the research stage at universities.
Parts made by hybrid pressure and injection molding of CFRTP and resins Parts made by hybrid pressure and injection molding of CFRTP and resins
Parts made by hybrid pressure and injection molding of CFRTP and resins

 

Daido Kogyo Co., Ltd.: CFRTP roll forming

Daido Kogyo has developed CFRTP roll forming processing technology. It is a continuous bending operation in which long bars (sash, etc.) and ring-shaped parts (bicycle rims, etc.) are formed from a long and thin strip of sheet metal. The strip coil is formed into final products as it passes through a set of rolls.
The new processing technology was developed to establish a highly productive process to promote the use of carbon-fiber-reinforced plastics (CFRP). The CFRTP material is bent under heat into long parts having a desired cross-section profile.

CFRTP roll forming processing technology

 

 



H-One's cold forging for ultrahigh-tensile steel sheets; Kurimoto's magnesium alloys

H-One: Cold forging technologies for ultrahigh-tensile steel sheets and 3D pipe heat-bending and quenching technologies

Cold forging technique for ultrahigh-tensile steel sheets H-One exhibited cold forging processing technology for ultrahigh-tensile steel sheet (UHSS). The company displayed a B-pillar manufactured by the new process. The B-pillars used on 2010 models were made of 980MPa that weighed 3.7kg. The company is now testing the cold forging process with 1470MPa UHSS that will reduce the B-pillar weight by 700g. Hard materials are prone to crack and torsion during the forging process. H-One has developed a new die structure to correct those defects. The 1470MPa UHSS sheet itself is a prototype but the company has already established a forging technique using the material. Once volume production of the material starts, the company will be able to start producing 1470MPa UHSS automotive parts.
3D pipe heat-bending and quenching 1470MPa-class iron pipe (having a closed cross-section) is quenched after high-frequency heating and cooled as it is bent to form desired 3D shapes. This technology was developed jointly with Nippon Steel & Sumitomo Metal Corporation and Nippon Steel & Sumikin Pipe Co., Ltd. According to H-One's calculation, the new technology will help reduce the part's weight by 30% compared to the cold forging of parts having an open cross-section. Its expected applications include bumper beams, A-pillars, cross-members and B-pillars. Production will start in 2015 initially in Japan and maybe later on in other countries.
Body frame rigidity increased by continuous welding and positions The use of thin UHSS enables weight reduction at the cost of rigidity. The company decided to modify the welding method to overcome this drawback.
Conventionally, the body frame is formed by spot welding along the flange center (where two parts overlap). H-One, jointly with JFE Steel Corporation, developed a new process characterized by continuous (linear) laser welding in the proximity of bends (press-formed corners). The new method increases the torsional rigidity by 13.5% while reducing the weight by 12.5% compared to the conventional method.
A prototype of a 1470MPa-class part A prototype of a 1470MPa-class part
A prototype of a 1470MPa-class part manufactured by the new cross-forging process. It is nearly free of folds that are seen in parts manufactured by conventional method (shown in the right-hand photo). A prototype of a 1470MPa-class part manufactured by a conventional cross-forging method has large folds (pointed by an arrow).
B-pillar made of 1470MPa material Prototype of 3D pipe
B-pillar made of 1470MPa material Prototype of 3D pipe formed by heat-bending and quenching
continuous laser welds
The dark lines pointed by the blue arrow are the continuous laser welds near the bend. The new method eliminates the flanges colored in orange, which leads to weight reduction.

 

Kurimoto, Ltd. : KEHMA flame-retardant and heat-resistant magnesium alloy for casting

Kurimoto, Ltd. has developed fire-retardant and heat-resistant magnesium alloy named KEHMA. It resists heat up to 200 degrees Celsius and has ignition temperature of around 1000 degrees Celsius. The alloy is not ignitable even in a dissolved state. It was presented as an alternate material for commonplace aluminum for die-casting application. The cost and durability remains to be solved for commercialization.

Characteristics and physical properties of the alloy

Specific gravity (g/cm3) Coefficient of thermal conductivity (W/m・K) Specific heat (J/kg・K) Linear coefficient of expansion (10^(-5) /Celsius) Young's modulus (GPa)
Flame-retardant heat-resistant magnesium alloy KEHMA 1.78 70.6 (at 23 degrees Celsius) 87.2 (at 177 degrees Celsius) 1,014 (at 23 degrees Celsius) 1,070 (at 177 degrees Celsius) 2.53 45.9
Magnesium alloy AZ91 1.81 51 1020 2.6 45
Aluminum alloy ADC12 2.7 92 (at 20 degrees Celsius) 963 (at 20 degrees Celsius) 2.1 71

Source: Brochures distributed by Kurimoto

 

 



Plastic processing: Sumitomo Bakelite, Toyobo, Ube Industries and Yamashita Electric

Sumitomo Bakelite: Long-fiber-reinforced thermoplastic compound molding, bonding of thermoset resin and metal

Long-fiber- reinforced thermoplastic compound molding Sumitomo Bakelite has developed a new molding technique for long-fiber-reinforced thermoset resin compound having high impact resistance. By adding a new process called 'unbundling tablet' before the compression molding in the die, the fibers in the resin are dispersed more evenly while maximizing the binding effect of the long fibers. Compared to the conventional method, the parts manufactured by the new method have higher strength and less strength variation. The new method is ready for commercial application, but has not received any order yet. Cost reduction remains an issue.
Bonding of thermoset resin and metal This refers to glue-less joining of metal and resin achievable by applying special surface treatment to the metal. The new process ensures higher material fill in the interface (joining area) resulting in better interfacial adherence. This allows manufacture of parts having characteristics of metal (rigidity, electromagnetic wave shielding, etc.) and those of resins (lightweight, insulation, heat resistance, etc.). Applications of the new method include weight reduction of electromagnetically shielded cases and development of highly functional structural parts.
A falling ball impact test A molded sample of aluminum and phenol resin
A falling ball impact test shows that long-fiber GF-reinforced resin part (bottom) is at least 6 times stronger than short-fiber GF-reinforced part (top). A molded sample of aluminum and phenol resin

 

Toyobo: Material for next-generation extension part and foam molding technology

Vylopet for molding next-generation extension parts Toyobo presented a new industrial material for making an extension part for headlamps. The material is already used on the Toyota Prius. Since gas generation from the material is minimal, whitening of the headlamp cover is unlikely.
Its high fluidity is ideal for making very thin (1.5mm) parts having complex design. Its smooth surface allows direct deposition. Since gas generation from the molten material is minimal, the die maintenance time can be reduced which increases efficiency of mass production. Vylopet is made from unreinforced PBT or reinforced PBT/ET alloys.
Foam molding Toyobo exhibited Mazda's engine covers made by its foam molding process. The process prevents the product's physical properties from declining when the product gets thinner by foaming.
Headlamp module exhibited by Toyobo Mazda's engine cover
Headlamp module exhibited by Toyobo Mazda's engine cover
Weight comparison of solid and foamed parts
Weight comparison of solid and foamed parts made of high-rigidity nylon material GLAMIDE (GF-reinforced grade). The foamed part weighs about half as much as the solid part.

 

Ube Industries: Polyamide for non-electrolytic plating

Ube Industries has developed polyamide material for making molded parts having good external appearance and strength. It has a high content of reinforcement (filler) along with high fluidity so that the glass fibers remain submerged. It has specific strength (tensile strength divided by density) similar to that of duralumin. When non-electrolytic plating (plating without hexavalent chromium) is applied, the material is given higher heat dissipation and electromagnetic shielding properties (plating technology is provided by Hitachi Maxell). Sample shipment started in October 2014.

polyamide material

 

Yamashita Electric: Y-HeaT mold temperature control technology that leaves no weld lines

A weld line is the line that sometimes appears where two flow fronts meet when there is the inability for them to 'weld together' during the molding process. A weld line usually occurs when the resin surface comes in contact with the die, gets cold and hardens when the two molten resin flow fronts meet. Weld lines are considered molding defects as they affect the external quality of the product. They are often corrected by coating at extra costs.
To challenge this issue, Yamashita Electric has developed a method to precisely control the temperature of the mold. The mold is heated during molding to prevent weld lines and cooled during the removal process. The company offers molding services by contract and also licenses the patented technology to other manufacturers.
Glossy part molded by Y-HeaT process A weld line is seen at 8 o'clock direction
Glossy part molded by Y-HeaT process (bottom) displayed under the same part molded by conventional process (top) A weld line is seen at 8 o'clock direction of the round opening of the part molded by conventional process
No weld lines are seen on the part molded by Y-HeaT processing
No weld lines are seen on the part molded by Y-HeaT processing

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