It can often be difficult to find the right spare parts for older equipment and vehicles. However, emerging technologies like additive manufacturing are transforming the market by enabling obsolete parts to be scanned then recreated.
When restoring cars it can often be a challenge to find replacement parts. This was one of the problems faced by UK-based Martin Stretton Racing, the historic racecar restoration specialist which runs one of the remaining Alfa Romeo Tipo 33/3 cars. The Tipo 33/3 was one of only 12 cars manufactured by Alfa Romeo in the late 1960s to compete in the World Sportscar Championships.
However, faced with badly damaged parts that have kept its Alfa Romeo Tipo off the road for several seasons, Martin Stretton Racing turned to KWSP.
3D printing skills
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. 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. The company therefore began looking for a replacement cover, but couldn’t find an exact match.
Martin Stretton commented: “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.”
So, Stretton took a tour of the KWSP facility. He said: “It was a real eye-opener for me. It showed what could be done with skilled engineers using 3D printing. 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 would not 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, and cracks rendered the component redundant. So, 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.
“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,” explained Stuart Banyard, head of advanced manufacturing at KWSP. “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.”
Once the digital asset was created, a 3D prototype was printed in a high performance thermoplastic called PC ABS. Printed overnight using one of KWSP’s Stratasys machines, the cover prototype was then 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.”
The final part was produced in aluminium for corrosion resistance. Stretton commented: “Thanks to this technology and the skills of the guys at KWSP we’re now back on the grid with the knowledge 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 the future.”