Pressing home the advantage

Original equipment manufacturer (OEM) performance targets for aluminum demand higher production speeds and lower costs. A manufacturing method promises to produce complex, high-strength aluminum pressings, potentially reducing material use and the mass of conventionally pressed aluminum structures.

Impression Technologies Ltd. (ITL) was formed in 2012 to bring to market the hot form quench (HFQ®) process developed within Imperial College, London, UK (see Figure 1). The process heats a shaped aluminum blank to its solutionizing temperature (500°C to 550°C) before pressing and rapidly cooling the workpiece while still in the tool. The now-formed part can be subjected to further treatment, ensuring the material reaches its full strength.

The technique

Aluminum HFQ structural components could reduce weight up to 20% compared with lower strength, cold-formed aluminum counterparts. In addition, the material’s increased formability at HFQ temperatures means parts can be deep drawn in a single operation, reducing the need for reinforcements. Removing the requirement for secondary forming operations also reduces tooling costs.

The essential features of the technique, says ITL’s Director of Innovations Dr. Alistair Foster, are that “it combines mechanical and heat treatment into a single forming operation.”

He explains this is achieved by raising the material’s temperature until it reaches the relevant solution heat treatment level. At that point, the alloying elements form a solution within the material and stay in solution after the in-tool quenching process initially provides a “W temper that will naturally age to a T4 condition, which can be artificially aged to an alternative temper, such as T6 condition” – the latter being the strongest possible state for the material.

The blank is held in situ to allow quenching of the formed part. Quenching the part in this way combined with optimized age hardening stabilizes the aluminum’s microstructure, delivering strength, formability, and productivity.

HFQ virtually eliminates springback – also known as elastic recovery – compared with cold-forming aluminum. John Sellors, director – applications engineering at ITL, says this has important implications for dimensional control during assembly operations and is something of interest to OEMs.

“With cold-formed, high-strength aluminum especially, springback can be a problem, but with HFQ, it’s reduced to nearly zero,” he states.

Innovation

Recently, ITL management announced the company’s collaboration in the Future Advanced Nacelle Technologies and Structural Integration Concepts (FANTASTIC) project led by Bombardier and supported by the UK Aerospace R&T program, a partnership between Aerospace Technology Institute (ATI) for Business, Energy, and Industrial Strategy (BEIS) and Innovate UK. The FANTASTIC project seeks to enable design and delivery of high-strength, high-accuracy, lightweight HFQ-formed components in aerospace-approved aluminum at lower cost than existing processes.

In a separate development, aluminum rolling and recycling company Novelis Inc. has agreed to partner with ITL to explore innovative ways to increase adoption of aluminum through the hot-forming process.

Currently, ITL has inquiries from several aerospace companies for applications such as seat components, wing ribs, wing flaps, engine inlet lip skins, and leading-edge slats.

Any shape or form

HFQ technology can solve many forming and assembly problems caused by cold forming and superplastic forming techniques. ITL offers aerospace component suppliers the opportunity to install HFQ manufacturing technology within their organizations by becoming a licensee, which gives access to support services to assist in designing and manufacturing HFQ technology components.

These services include:

• Design & simulation – ITL team assists companies to maximize cost-effective mass reduction of complex, high-strength HFQ aluminum panels
• Development – ITL team reduces the number of press tools required to produce a part, significantly lowering the required investment
• Prototyping – ITL’s facility carries out in-house production runs, supports HFQ technology customers
• Tooling – In-house prototype, production tooling try-out facility, with assistance from expert know-how team
• Training – Customized training courses covering each aspect of the product life cycle

ITL plans to continually develop HFQ technology to ensure the benefits of the technology are maximized for future use.

Impression Technologies Ltd.