With this year’s end stage of a major collaborative R&D project, the longstanding competition between steel and aluminum for high-volume vehicle production is set to literally heat up. Called RACEform, the project will validate Impression Technologies’ Hot Form Quench (HFQ) process for the mass production of complex aluminum components and structures.
The HFQ’s promise to enable more-extensive use of aluminum promises to save both weight and cost – while potentially signaling new design and manufacturing opportunities. Until now, HFQ’s applications have been for relatively low-volume, high-end niche models. But boosted by electric vehicle (EV) development’s enduring thirst for range-enhancing reduced weight – while simultaneously working overtime to reduce showroom prices – it could make the leap to high-volume applications.
The process is all about the use of deep-drawn, complex aluminum components and structures manufactured from high-strength, ultra-high strength and recycled aluminum, delivering up to 20% weight reduction compared to some conventionally-pressed aluminum grades. The RACEform (Rapid Aluminum Cost-Effective Forming) project, initiated in November 2017 with financial support from the U.K. government-backed Advanced Propulsion Center (APC), involves a joint industry and academia group working together to validate the HFQ components and parts design and manufacturing process for high-volume structural applications. Jaguar Land Rover (JLR) research also is linked to the project.
Commercially developed by project leader Impression Technologies Ltd. based on academic research, HFQ applications would include mass-production body-in-white (BIW) and chassis assemblies – particularly for EVs and expandingly popular SUVs, said the Impression Technologies CEO Jonathan Watkins. “As a technology, HFQ offers Tier 1 suppliers the opportunity to advance to volume component production manufacturing within 12-18 months depending on current plant configurations,” he said.
Watkins regards HFQ as delivering the opportunity to minimize investment through the re-purposing of current manufacturing lines. “The technology is already embraced by OEMs including Aston Martin (for the DB 11’s tight-radii A-pillar) and Lotus, with others working on projects globally,” he said, adding, “Not only is HFQ technology compatible with recycling, it is an enabler to recycling as the process conditions help the alloy retain its necessary forming ductility even with the contamination arising from a wider range of recycled input sources, allowing lower cost highly recycled alloys to be used, further impacting on profitability and sustainability.”
Impression Technologies, which already claims to be the operator of the world’s first HFQ production line, has achieved steadily rising parts output. This year, it is expected to reach 100,000 units, demonstrating what Watkins describes as proof of OEMs’ commitment to the technology.
Aluminum vs. steel
The HFQ process also is claimed to help aluminum compete with steel on affordability, while additional weight reduction is achieved via parts integration and the deletion of joining flanges. HFQ Technology (Impression Technologies’ registered name for the process) is claimed to reduce parts cost through down-gauging of panels and by combining multiple conventionally-formed and -assembled panels into a single pressing. In addition to vehicle A- and B-pillars, potential examples of parts integration include front headers, dashboard panels, sills, battery enclosures, door inners, door intrusion and bumper beams, chassis components and seat structures.
Watkins also said that HFQ Technology enables investment reduction thanks to deletion of multiple forming tools and reduced parts count, which also drives assembly savings. Meanwhile, the process is sufficiently rapid to meet the cycle times required for low-cost, high-volume manufacturing.
“The first stage of the HFQ process is to heat a standard, heat-treatable grade of aluminum sheet in a furnace until it reaches its solutionizing temperature (around 550°C) – this will vary depending on the grade of aluminum alloy. The blank is then transferred from the furnace to a press and formed between a cold punch and die tool,” Watkins explained. The tools remain closed for less than five seconds, allowing the formed part to be rapidly quenched. For all aluminium grades, quenching freezes the microstructure of the alloy in a supersaturated solid solution state. “During the forming process, there is in effect virtually no cold working of the aluminum alloy, eliminating the need for complicated springback compensation in the part or tool design,” he added. If required, heat-treatable aluminum alloys can subsequently be artificially aged to further increase the strength of the pressing.
Originally conceived at the UK’s University of Birmingham in 2003 and developed at Imperial College, the HFQ process was then commercialized by Impression Technologies. The RACEform partners Impression Technologies, Imperial College, Chemetall, Innoval, and Brunel University’s Center for Advanced Solidification Technology. Watkins stressed the importance of close collaboration, with each partner focused on specific areas.
Imperial College led on structural-adhesive bonding and pre-treatment testing. Researchers have completed surface pre-treatment and analysis evaluations, supported by Chemetall and Innoval; they also have characterized the microstructure and surfaces of samples. Brunel University is running a self-piercing rivet program together with structural simulations and evaluation and modeling of joining methods. Global Tier 1 supplier Gestamp has successfully carried out high-volume HFQ proving and production trials at its volume hot-stamping plants in Germany and Spain, achieving cycles times of under five seconds for A-pillar components in high-strength aluminum.
JLR’s new REALITY
To prove the technology’s recycling capabilities using lower-grade aluminum, RACEform is being supplied with highly-recycled aluminum sheet from JLR’s REALITY “closed-loop” recycling initiative. Testing will take place to confirm that the HFQ process can maintain what Impression Technologies describes as “excellent formability even with high levels of impurities” and analysis of the resulting parts, adding that early forming trials have been successful.
JLR said it is developing the next phase of its aluminum closed-loop strategy with a recycling initiative to “transform the vehicles of today into the cars of tomorrow.” The REALITY project aims to recover aluminium from existing Jaguar and Land Rover vehicles and reform it into a new, high-grade aluminium to create newly-manufactured vehicles.
The process tested on pre-production Jaguar I-PACE cars which had their batteries safely removed (those batteries enter their own second-life process JLR is developing) while the scrap from the recycled vehicles is sorted into various groups using high-tech sensors by Axion. Once separated, the aluminum scrap is melted and reformed. When operating at full capacity, REALITY is expected to reduce the CO2 impact of production while also reducing the amount of virgin aluminum required to produce new vehicles. The company recently said it had reduced its global vehicle-manufacturing operating CO2 by 46% per vehicle.Continue reading »