Something noted on the cars over the opening race of the year was the presence of matt black aero components on the cars. Not carbon fibre and not metal, the tell tale surface finish shows that teams are using parts manufactured in special resin produced in 3D printers via the technique of rapid prototyping.
For some years Stereo Lithography (SLS) has been used at the factories to make parts for wind tunnel models, casting moulds and mechanical mock ups. SLS is the process of making a 3D part by solidifying a liquid or powdered resin, one a layer at a time. Even though hundreds of layers are required to make a single component, the process is now more commonly termed rapid prototyping (RP). This creates a solid 3D part often made with with a distinctive orangey coloured resin. By taking the data from the teams CAD systems, RP allows parts to created accurately rapidly and also to a chosen scale. All without recourse to other machining or hand working. While this technology is commonly seen at the factory, the results had not been seen out on track as the resins were incapable of withstanding the stresses of mechanical, aero or thermal loads. Subsequent development of better materials has now allowed the teams to go from 3D CAD data direct to finished parts on the car. This short cuts the existing process to make parts from patterns, moulds and finally the laying up of carbon fibre. Reducing the lead time for a component from weeks to hours. Additionally the ability of RP to replicate the exact shape and thickness of the part as it was designed allowed designers and production engineers to create even more complex surfaces and wall thicknesses not easily created with carbon lay ups. Details such as wall thickness tapering into sharp edges and corners. As result a RP component can open avenues to designers not easily accessible with conventional manufacturing techniques.
Teams are increasingly using RP (rapid prototyping) materials on the race car itself. Most commonly for the complex front brake duct scoops. I picked up on this when Red Bull first used them in 2006. In Bahrain 2010 several teams had the distinctive looking matt black ducts bolted to the front of their cars. Although the duct is not a highly stressed part, it does have to meet the airflow head on and is placed relatively near the front brakes, so when the car is at rest the heat will soon pass through to the duct. thus the component does suffer some stress and heat. Red Bull using the Windform XT RP material (Windform.it) are able to engineer a duct that copes with both the heat and loads seen by these components. Windform XT is Carbon filled PA resin, which is not as strong as carbon fibre, so it does not suit all structural parts. Previously the Red Bull used RP materials with an alumised coating to provide thermal protection, the more durable XT material alleviates the need for this secondary process, further enforcing the “rapid” element of RP.
Lotus also appear to have used RP parts within their rear wing. On the rear wing endplate the stack of louvers were not moulded into the carbon fibre, but rather made from RP material and bonded into the endplate. This is the first evidence I’ve seen of RPM being bonded to a carbon part. The benefit that the profiles and edges can be far sharper in RP than Carbon fibre.