Concept
Material Selection
Material Selection
I was playing around with a 3D pen when the thought of it being used to inject molten plastic crossed my mind. Its Highest temperature is 230°C, this device is nowhere near an actual injection setup, and its drawbacks will be present in this experiment.
Material Selection
Material Selection
Material Selection
The most important part of this process. PETG was chosen to be the mold material, as it has a high melting temperature, around 260°c. PLA was chosen to be the injected material, its melting temperature is around 200°C. I also discovered that PLA and PETG do not stick together so well, influencing my material selection.
CAD
Material Selection
Prototypes
This is one example of the many CAD iterations I went through. The overall concept was kept throughout. Two halves modeled around each other, with a cavity for molten plastic in the middle, able to be clamped together with some M4 screws. More pictures below.
Prototypes
Results and Takeaways
Prototypes
Finding the limits of my makeshift setup was time consuming. Whether it be the interface between the mold and pen, cavity shape, and determining if runners and sprues were needed. More pictures below.
Trial and Error
Results and Takeaways
Results and Takeaways
You can see the progression of attempts clearly here. V1 produced mostly blobs of plastic. V2 the product started to take shape. V3 I was dialing in the injection system (results were worse). V4 embodied a new shape and could not correctly accept the plastic.
Results and Takeaways
Results and Takeaways
Results and Takeaways
News flash, a proper injection molding setup is needed to do actual molding. But I am happy with my results. It was a fun experiment and I continued to master my engineering skills. Lots of different variations were tried. I was most happy with my results in V3, l was able to get 6 really consistent results in under 5 minutes.