Stage 1: Test Car Manufacturing
We decided to machine a test car, even though it would take us more time. This ensured that the actual car was of the highest quality, and to ensure that we knew what we were doing. Machining the test car enabled us to learn the manufacturing skills that are required.
Stage 2: CNC Machining Of The Actual Car Body
We are manufacturing the main part of our cars using a CNC (Computer Numerically Controlled) Router. The body is manufactured out of a balsa wood block, which is supplied by F1 in schools. The block that we manufactured our first car out of weighed 64 grams before machining, meaning that once the body was machined, it had a mass of just over 9.3 grams.
Stage 3: Sanding And Rear Wing Assembly
Once the car had been machined, we sanded the car down to get rid of the marks from the CNC process, and then attached the rear wing using superglue. We had manufactured the rear wing separately from the body, but from the same block of wood. This meant that we could machine from the top and the bottom, so we could get the channels under the car.
Stage 4: Regulations Check On Body
To ensure that we complied with all the regulations (except T4.3, see Design), we decided to 3D print a set of manufacturing calibration tools, to check various measurements around the car. We would be using these, as well as digital callipers, to check distances and regulations at every stage of the manufacturing process.
Stage 5: Front Wing Manufacturing
The next step of the manufacturing was to 3D print the front wing of the car. We wanted to manufacture our front wing in red plastic, so we printed the first wing using red ABS filament, which we had an excess of. This turned out to be a complete disaster, because we did not realise that ABS plastic is prone to warping if it is used for 3D printing. Our teacher then said to us that he had a sample of red PLA filament that we could use, but he only had a small sample which was 5 meters of filament. PLA does not warp, so the next print was a success. Because we only had 5 meters of filament we had to be careful with our print settings to make sure we used a minimal amount of filament.
Stage 6: Painting
We have begun to paint the car by first coating the car with spray putty, to fill in the gaps in the balsa wood. We then sand that down and spray on another coat, which we then also sand down, for optimal smoothness. Once the spray puttied car was sand down we applied the actual paint. We went for a deep blue in keeping with our team colours.
The car after the first coat of putty was sprayed on.
The car just after the second coat of paint had been applied.
Stage 7: Car Assembly
After we had finished painting the car, we cut the carbon fibre axles to size, interred the grommets into the car, glued the front wing on, and finally inserted the axles into the car and glued the wheels onto the edges of the axels.
The car during assembly.
Stage 8: Adding Mass
Because we designed our cars to be as light as possible, they were under the minimum mass of 50 grams. To raise the mass of the cars, we decided to plant screws underneath the bottom of the car, so that they were flush with the surface. Because it is difficult to find the screws with exactly the right mass, we added a little more superglue to the car to add more mass, which also increases the car’s strength.
The final mass of the cars:
Car 1: 50.04 grams.
Car 2: 50.01 grams.
The three screws put on car 2 to achieve the minimum mass.
The Finished Product:
Four months after we started the project, we have the completed cars.
The finished cars, car 1 to the left, car 2 to the right.