Stephen has been with PlasticsToday and its preceding publications Modern Plastics and Injection Molding since 1992, throughout this time based in the Asia Pacific region, including stints in Japan, Australia, and his current location Singapore. His current beat focuses on automotive. Stephen is an avid folding bicycle rider, often taking his bike on overseas business trips, and a proud dachshund owner.

The entire production cell for the carbon rims measures a compact 16 x 12 meters (52.5 x 39.4 ft), including the enclosure. Image courtesy of KraussMaffei.

A carbon preform, prepared by the customer, is placed over the inner core of the mold, and four sliders, which form the round outer contour of the rim, then move simultaneously. The press closes and the epoxy matrix material is metered through a distribution star. After a curing time of approximately 15 minutes, the mold opens, the sliders open, and an ejector ring presses the rim body, which has shrunk to the core (20 inches in diameter), upwards. The mold is flexible from 18 to 22 inches in diameter with a rim width from 8 to 12 inches. The tool weighs in at 4.9 tonnes and delivers incredibly precise concentricity of 20 µm.

Anyone who plays golf and is keenly aware of the importance of club weight has probably held an AIM product in their hands. The company has a global market share of around 80% for carbon-fiber golf clubs (under various brand names), and also has a track record in the bicycle market. For around 30 years, various composite technologies have been part of the standard repertoire. When AIM first ventured into the automotive sector, however, know-how from KraussMaffei was in demand, as this would be the first time it put an HP-RTM system into operation. Carbon-composite wheels have emerged as a hot topic of late. OEMs such as Jaguar Range Rover, Chevrolet, and Hyundai all offer the option on select vehicles.

In comparison to low-pressure processes, HP-RTM requires more complex dosing technology, but also delivers consistently high-quality components with exceptionally precise surface quality — all in short cycle times, which are particularly important in the automotive industry. In the beginning, the AIM team first wanted to get to know the new technology of the system. As Tyson Hsiao, R&D manager at AIM, explains: “Fredrick Su, our sales partner at KraussMaffei, listened carefully, and then put together a package that we could use in an HP-RTM cell to recreate both high-pressure transfer molding as well as wet molding and compression RTM for small production series. We were really impressed by this.”

To retain the vacuum in the mold and prevent low-viscosity material from escaping, the team strove to achieve the best possible manufacturing precision and with it a good design. The locking force is generated by four barrels on the top of the master mold and locking elements mounted underneath, which move into recesses on the sliders and block them. With a mold temperature of 120 to 130°C (248 to 266°F), protection of the pneumatic and electronic components with insulation boards was necessary.

The HP-RTM cell package consists of an MX press with a clamping force of 10,000 kN, a RimStar Compact 8/4 HP-RTM metering system, two robots for metering and handling (with different grippers), and a sophisticated mold solution. The system’s 16 x 12-meter (52.5 x 39.4-ft) footprint represents a relatively compact design.

Fusible-core injection molding technology has been employed to mold a fuel housing for an aircraft using PEEK (polyetheretherketone) resin supplied by Victrex (West Conshohocken, PA). The solution reportedly delivers a 30% cost saving and up to 50% weight reduction versus existing metal designs.Processor Egmond Plastic was able to consolidate the number of parts using a carbon fiber reinforced grade of Victrex PEEK polymer. A separate bearing, for example, was eliminated since it is now integrated into the overall design of the housing.Fuel housing molded for CF-PEEK compound using fusible core process.Fuel housings for aerospace applications have very complex inner geometries which are not moldable using conventional injection molding technology. Egmond Plastic's fusible-core technology enables moldings of complex hollow housings, manifolds, and pipes. Richard Brandwijk, Managing Director at Egmond Plastic, explains: "Our technology, in combination with carbon fiber reinforced Victrex PEEK polymer, delivers numerous benefits. These include cost reduction, enhanced manufacturing speed, and weight reduction leading to improved fuel efficiency and reduced CO2 emissions. Along with part consolidation, this exceptional technology and material combination enables the design of very complex parts, beyond the capabilities of standard injection molding and metal processes."Utilizing a near net-shape manufacturing process for the fusible core allows for an 80% time saving versus machined parts. Further, secondary treatments for corrosion protection, such as anodizing, can be eliminated. Lead times can be reduced by 50%. These factors combine to deliver part cost savings of more than 30% versus metal equivalents."The global aerospace industry stands to gain enormously by persistently replacing metals in key applications, in which Egmond has demonstrated tremendous leadership," said Uwe Marburger, Aerospace Business Development Manager at Victrex. "Clearly, our PEEK knowledge and material solutions help enable the use of a technology that addresses some of the toughest challenges in complex aerospace part design and productions."Previously, the end-user had generally specified aluminum for the production of fuel containing parts, but a carbon fiber reinforced PEEK polymer demonstrated superior fatigue performance when compared to aluminum. It does this while meeting all the engineering requirements for this application, including stiffness, effective flame, smoke and toxicity (FST) performance, and resistance to aggressive chemicals, including notably, for this aerospace application, resistance to jet fuel and Skydrol hydraulic fluid. Parts can range in size all the way up to 30 cm x 30 cm x 40 cm (11.8 in x 11.8 in x 15.8 in), and typically the process is used for production runs of up to 2,000 parts.Egmond's unique fusible-core technology has already established a proven track record using Victrex PEEK in a fuel pump for the Eurofighter Typhoon, a jet fighter in use in several European countries. This pump has been in successful operational use for more than 20 years.

Golf clubs, bicycles — and now automotive, too: Together with KraussMaffei, Taiwanese composites specialist Advanced International Multitech (AIM) is expanding its portfolio to include high-pressure resin transfer molding (HP-RTM). AIM is now producing automotive carbon rims on a complete system with sophisticated tools.

The many moving parts in the mold were cause for the greatest challenge, which was to seal the complete system at a high cavity pressure. Normally, the pressing force alone is sufficient to seal a mold, where the horizontal sealing surface is located solely between the upper and lower parts of the mold. In the case of the rim project, however, the undercuts and C-shaped contours of the part required four sliders to enable demolding, not to mention the moving ejector ring.

A concrete project soon followed. Carbon rims tend to occupy a niche in the automotive sector yet are extremely lucrative because they are in the high-price segment. A material mixture is common in this case: A rim body made of carbon-fiber-reinforced plastic (CFRP) to which the visually appealing aluminum wheel spider is bolted. These wheels are approximately 20 to 30% lighter than those made of pure aluminum and, at the same time, are around 20% stronger than all-aluminum rims. Sporty and ambitious drivers can accelerate faster thanks to the reduced weight and, with more of the unevenness of the road dampened by the suspension, the driving experience is also more pleasant. If you want to deck out your vehicle with carbon rims, you have to dig deep into your pockets, though: €10,000 to 15,000 ($11,000 to 16,600) per set is common.

Fusible-core injection molding technology has been employed to mold a fuel housing for an aircraft using PEEK (polyetheretherketone) resin supplied by Victrex (West Conshohocken, PA). The solution reportedly delivers a 30% cost saving and up to 50% weight reduction versus existing metal designs.Processor Egmond Plastic was able to consolidate the number of parts using a carbon fiber reinforced grade of Victrex PEEK polymer. A separate bearing, for example, was eliminated since it is now integrated into the overall design of the housing.

Advanced International Multitech, a giant in the carbon-fiber golf clubs space, has installed a high-pressure resin transfer molding system to produce carbon rims for automotive OEMs.

The tooling set applies a master mold and uses several mold packages for the different rim diameters. This gives the customer a lot of flexibility.