Reducing design time and part weight have become the new design goals. Today’s students are learning them too. The student motorsport team Tecnun is using a Stratasys 3D printer to create complex end-use race parts. The students are able to reduce the time it takes to create these parts as well as their weight by 3D printing sacrificial cores to innovate composite part production.
Tecnun, the Formula student team from the University of Navarra in Spain, designs and manufactures its own Formula Student racecars that compete each year at the Formula Student International competition. Harnessing Stratasys’ additive manufacturing technology through the its local reseller, Pixel Sistemas, Tecnun can produce extremely complex 3D printed molds for key race parts in a matter of a few hours, compared to three weeks when using traditionally manufactured aluminum molds.
Using the time saved during production, the team can make further iterations to its designs and develop final carbon fiber parts that are 60% lighter than conventional production methods. The lighter weight helps increase the cars’ performances on the track.
As Javier Aperribay, Technical Director of Tecnun Motorsport, explains, crucial to success and one specific area in which Stratasys’ technology can be successfully deployed, is the design of the intake manifold – a component that ensures enough air reaches the engine cylinders.
“Manufacturing an intake manifold is complex as it comprises several important components critical to the air distribution along the four intake manifolds,” Aperribay says. “We aim to create intake manifolds in carbon fiber composites, but we’re well aware that manufacturing such a part requires a mold to lay-up the composite materials and create the final part.”
“CNC machining is used to produce the mold in aluminum, however this is typically an inflexible and costly process and on top of that, any subsequent design revisions applied to the mold delay projects and add extra costs,” he adds.
Invariably hamstrung by tight production schedules and budgetary constraints, Tecnun has in the past tested various other additive manufacturing technologies as faster and cheaper alternatives to produce the lay-up tool. However, it found that the plastics were not strong enough and broke during the lay-up process.
Working with Pixel Sistemas using a Stratasys Fortus 450mc Production 3D Printer, Tecnun is successfully producing mold tools for parts like the intake manifold. This is 3D printed in ST-130 sacrificial tooling material, before the carbon fiber composite material is wrapped around the mold. Once cured, the internal sacrificial core is washed away, leaving the final composite part.
“Using Stratasys FDM sacrificial tooling allows us to make the intake manifold from carbon fiber instead of heavier, less efficient materials,” says Aperribay. “The superior soluble characteristic of the ST-130 material enables a more complex shape of the intake manifold compared to aluminum molds, removing the need to assemble all the individual components. We can now 3D print molds for the intake manifold in just five hours, as opposed to the three weeks lead time associated with conventional aluminum molds.”
According to Aperribay, the team is also impressed with the performance of the 3D printed sacrificial core molds during the carbon fiber lay-up and curing processes.
“We find that the material performs in high temperatures of up to 121°C and, at certain temperatures, pressures of up to 620 kPa throughout curing,” he says. “Unlike the previous additive polymer materials, we tested, the mold doesn’t break, and the quality of the resulting carbon fiber composite intake is fantastic.
“Using this technology has facilitated the combustion reaction and has increased performances on the track,” says Aperribay. “Moving forward, there is very little doubt that FDM sacrificial tooling will play a crucial role in overcoming our ongoing engineering challenges.”
“Tecnun’s use of 3D printed sacrificial cores to reduce production times and increase part complexity – and their use of this time-saving for further design iterations to produce what are ultimately much lighter parts – mirrors the way some of professional motorsport’s best-known teams are also benefitting from our technology,” says Andy Middleton, President, EMEA, Stratasys. “For us, it is thrilling to see tomorrow’s engineers embrace this technology so successfully as the rise of additive manufacturing continues within the automotive sector.”