The objective of this project was to create a small yet sturdy retractable utility blade. The design needed to be 3D printer compatible and have a low print time. This part went through multiple iterations to ensure that it met the user requirements. Similar designs already existed online but few of them had been rigorously tested therefore they are prone to design faults and are difficult to use.
The Utility Knife was designed in Solidworks while always considering how to optimise designs for manufacturing techniques. FEA of the part was not conducted as the inherent anisotropic nature of 3D printed parts would make the results inaccurate. I instead tested the knife over the course of 4 weeks and optimised the design accordingly to improve durability and tolerances.
After 4 weeks of testing and altering the design I arrived at the most efficient and durable design. The final model prints 22% faster than the original and the shift to PLA over of PETG coupled with the design changes meant the knife could withstand up to 50% more load. However, the change in material came with a trade off as the impact resistance decreased by around 35%.
The new utility knife features a more aesthetically pleasing design and a folding blade. The complex design meant a 300% increase in print time. However, this model is far more durable and the folding blade design is more sturdy.