Additive manufacturing reanimates historic Alfa

Additive manufacturing processes are transforming industry’s response to the spare parts problem in the historic motorsport market.

Combined with digital scanning techniques and employed by skilled engineers, these tools can be used to help re-manufacture one-off, original parts quickly and often at a fraction of the cost of traditional methods.

The background

The Alfa Romeo Tipo 33/3 was one of only 12 cars made by the Italian manufacturer in the late-1960s to compete in the World Sportscar Championships.

Run by Autodelta, the works team, the car initially struggled, but found major success in 1971 at races in Buenos Aires, Sebring and Brands Hatch. It went on to gain a faithful following, and even played a starring role in the Hollywood movie, Le Mans, alongside Steve McQueen.

One of the remaining Tipos is being run by UK-based Martin Stretton Racing, a leading historic racecar restoration specialist. Like many race teams and restorers alike, Strettons is faced with a challenge that will only get harder as historic cars get older – the replacement of original parts.

The engineering challenge

Faced with badly damaged parts that have kept its Alfa Romeo Tipo off the road for several seasons, Strettons turned to high performance engineering business KWSP to bring its rare works 1971 Alfa Romeo Tipo back to the grid.

The car’s original, naturally aspirated, three litre V8 engine was in good working order, apart from a problematic front engine cover, which had deteriorated significantly in recent years and had been subject to numerous running repairs.

As an integral working part of the vehicle’s powertrain, the poor condition of the front cover had become a major issue. The final straw came when the car failed to start.

Martin Stretton explained: “This is a rare car, so when searching for a replacement cover, the options were limited.

“We found several alternatives that were close, but none of them were exact matches for our Alfa Tipo 33/3. In the end, we had to explore other avenues.

“Having investigated the pattern making route, using skilled model makers, we realised that this would be a technically difficult project to deliver. It would also be prohibitively expensive.

“It was at this time that we began talking to the team at KWSP who invited us to visit their facility – next to Mercedes Petronas F1 – in Brackley, Northamptonshire.

Stretton continued: “Touring the KWSP facility was a real eye-opener for me. It showed what could be done with skilled engineers using additive manufacturing.

“Components, body panels and complete structures can now be scanned, digitised, designed for manufacture and made within days using this approach. Previously, much of this wouldn’t have been possible. And if it was, it could have taken months.”

The right solution

Originally cast in lightweight magnesium alloy, the Alfa’s engine front cover had lost form and function. Unsightly welds were no longer keeping up with the number of cracks that now rendered the component redundant.

Having decided to remanufacture five new covers, the KWSP team set to work creating a digital CAD file of the component. This stage of the process involved scanning the badly corroded engine cover, along with the original water pump and housing.

However, meeting this challenge comprised more than simply scanning the original part. Stuart Banyard, head of advanced manufacturing at KWSP, commented: “While we had the original part to scan, undertaking a simple like-for-like photocopy operation would not solve the problem, as the original part we had was defective.

“This is where the real value of our consultancy comes in. We were able to create a digital scan of the part – and then crucially, make vital changes to the design to bring it back to its original geometry and functionality.

“Intelligent use of CAD data allowed us to use the scanned part as a reference, enhancing structural elements as required to recreate the component into its intended form. This part of the process requires a lot of decision making from our design team, examining draft angles and other integral geometries of the CAD.”

Eventually, a finished digital asset was created. Before committing to the casting process, a 3D prototype was printed in a high performance thermoplastic, PC ABS. Once printed overnight using one of KWSP’s Stratasys machines, the cover prototype was fitted to the engine to confirm proof of concept.

Banyard added: “This is an important stage of the re-manufacturing process as it enables us to make any final changes to the design, without incurring significant cost.

“On this occasion, the part fitted perfectly and we were able to move straight to the finished casting process.”

Back in the race

With the new aluminium (not magnesium, for reasons of corrosion resistance) engine cover now fitted, Martin Stretton said: “Without additive manufacturing, it would have been a lot more difficult to put this great Alfa on the road again. Of course, there are alternatives, but they would have been more than three times more costly – and less accurate.

“Thanks to this technology, and the skills of the guys at KWSP, we’re now back on the grid with the knowledge that that we also have spare parts should we need them in the future. Even better, we have our own digital asset in the CAD file, which can be enhanced and amended should we want to explore this option in future.”

Scanned, re-designed and prototyped in just a few days, the Alfa’s engine cover shows how quickly the digital remanufacturing process can take. While still adhering to both the letter and spirit of FIA certification, additive manufacturing has huge potential in the historic motorsport market.