The other day I was able to cast the silicone molding media to make the mold for the QD embedded plastic pieces. The molding media I bought doesn't require a vacuum as I previously thought, so I was able to cast it at home in my kitchen. It is very simple to do as it is simply a 1:1 volumetric ratio. I borrowed some multipurpose mold release from out school's "Tinker" lab, and it seemed to work just fine.
The specs for this design have been developed. Recently I've been working on making the molds to cast the QD plastic in. I purchased a tin-cure silicone molding media which meets the temperature requirements of the vacuum oven the plastic will be cured in. I selected tin cure over platinum cure because we have access to a vacuum chamber to de-gas the molding media as it cures, and it's a bit cheaper than the platinum cure. It also works with a wider variety of materials. The library life is not as long as the platinum cure, but that is not really a concern for this application.
I milled the positive for the mold out of aluminum. I then lasercut some acrylic to form a cavity around the positive in which to cast the mold media which will become the negative. The result will be a simple open faced mold. If the results from this mold are no good, we may try a 2 part mold, but I think a 2 part mold would be overkill for this part.
- I have a design for the box, but I need to make sure it can be made with an efficient use of materials, and easy to assemble, as we will be making many of these devices.
- I need to further embody the electrical design by selecting a UV source. I am having trouble designing a UV LED array that meets the light intensity requirements to activate the QDs while being at a reasonable cost. The UV LEDs are quite expensive, and I'd need a lot of them. I'm considering reverting to a fluorescent source if it turns out to be cheaper.