Aluminium wings get production flying

Construction of the coveted Morgan car benefits from the combination of modern and traditional techniques.

A more curved body shape, better hood line and increased visibility are features of the newest Morgan sports car. The cars also have one-piece wings made from SPF (superplastically formed) aluminium.

Aluminium is substantially lighter than the three-piece steel components they replace, and the new wings retain their distinctive shape while improving corrosion resistance and reducing paint protection costs. Gauge for gauge, aluminium is around 60% lighter than steel, with higher impact absorption properties and better strength to weight ratios. It is also fully recyclable – in the case of SPF aluminium alloys, for less than 5% of the energy required for their original manufacture.

Add to these the advantages of low cost tooling – typically 10% of matched die stamping – rapid prototyping and enhanced design freedom, and it becomes clear why a number of US and European car manufacturers are attracted by the process and already using it for body and door panels.

The Morgan’s new wings are cavity formed by specialist supplier Superform Aluminium from 2mm starting gauge 5083 SPF alloy. Employing a blank 3.2m long by 1.5m wide, the two-part cast iron tool weighs 7.5 tonnes. This is also the largest reverse engineering project undertaken by toolmakers, Survirn Engineering.

A CAD model existed of the car body, but not the wings so these had to be digitised in situ. Using a Faro 6-axis digitising and measuring arm, data points were collected across the full width and length of each wing, from which sections were created for CAD model generation. This data was used to construct a full CAD model on CATIA workstations from which Survirn’s in-house CAD-CAM facility, CAMCrafi Design, was able to design the tooling in conjunction with Superform. A small-scale model of this computer-generated wing was delivered to Morgan for approval. The new wings dramatically improve the quality of fit and surface finish on the +8, +4 and 4/4 models.

Charles Morgan said: ‘Adoption of the superforming process combines traditional coach building skills with state-of-the-art manufacturing technology. The finishing of each wing is still a job for craftsmen at our Malvern factory, but the new process has given us much more accurate blank to work from, guaranteed repeatability and a very good surface finish’.

Superform Aluminium. Tel: 01905 874300