This is an update from our friends at FM-1 Team Racing – Formula 1 in Schools Team.
Our team is very fortunate to have been sponsored with an Ultimaker 2+ Fused Filament Fabrication 3D printer from CREATE Education. This was used to manufacture all components of the race car, excluding the foam chassis. It was also used to construct the wind tunnel , and rapidly fabricate experimental prototypes. We exploited the full versatility of the printer to produce accurate, lightweight and strong parts.
The Front nose being printed using a 0.25 nozzle for high accuracy. For the most efficient configuration of material usage and part strength, the part was printed hollow, with a thick wall using PolyHydroxyAlkoanate (PHA) biodegradable thermoplastic. The front nose is divided into two parts, the first which includes the front wings, support systems and the tether slot, the other featuring the axel mount for the front wheels, the reason for this is to reduce the amount of support material used. The complex and intricate geometry of the nose made it a challenging print, however the outcome was perfect.
Two different slicing programmes were used to write the .gcode for the printer: Cura and Simplify3D. Using these slicers, we could define exactly how we wanted the parts to be printed. With over 300 different parameters and settings, we could produce each part to our specifications.
Simplify3D allows the entire print to be simulated, enabling the user to notice and correct any possible problems or errors before it is sent to the printer. Shown above is the simulation of the front nose. This particular simulation highlighted the lack of support material underneath the curve of the tether slot. This was subsequently changed, allowing for the flawless print shown at the top to the left. The print was oriented nose-up, allowing the upright surfaces to be printed much more accurately, as the printer builds the part layer-by-layer.
PolylacticAcid (PLA) is one of the most versatile materials used in 3D printing. It is relatively strong, lightweight and has a low coefficient of kinetic friction. This made it the perfect choice of material for the wheels of the car. The high accuracy of the printer, on all three axes, enabled the eight pins of the two cylinders to slot into each other perfectly, similarly, the bearings, shown mounted inside the wheels, inserted tightly into the wheel bodies with ease. The wheels were printed hollow, enabling them to spin faster. Any support material or infill would result in the wheel not being axisymmetric, which would cause it to rotate slower. Because of this the rotating parts of each wheel system weigh less than one gram, allowing it to rotate with minimal resistance.
The rear wing module was perhaps the most difficult set of parts to print, due to their shape and dimensions. It was fabricated as three separate parts so that the wings would be printed as smoothly as possible, reducing aerodynamic friction as the air flows over and below the aerofoils.
This fully 3D printed experimental mock-up of the race car was used to analyse the assembly of the car and for wind tunnel use. All aspects of the physical testing and analysis of the car had 3D printing heavily involved, due to its low cost, high speed and its ability to produce almost anything. This car features 22 individually printed components, which were then assembled and mated together, using the parts’ skin friction or adhesives. This car gave a lot of insight into how the car will perform when the lights go out on race day. It was printed with PLA and PHA with a 0.25mm nozzle for every component except the central chassis, which used a 0.6mm nozzle.
Using finished, pre-manufactured axels for our car was not an option, due to the shape that we desired. The additional weight of a metal is also undesirable. PHA, which has a higher elastic modulus than PLA was used to print the axels of the car. Despite being only 2.37mm in diameter. These axels can support the weight of the car as it speeds down the track.
The CREATE Education Project would like to thank Omar Salem, Tim Farrelly, David Deneher and Lucy Quinn at FM-1 Team Racing for providing us with this update and insight into how 3D printing is being used throughout their project. Learn more about their project.