The 3D printing process worked fairly well to produce a good model. The design had a 'menu' button but because of how small it was the printer wasn't able to do it. The other buttons did get printed but they were really small and very delicate. This would make it too difficult to get a good finish on and therefore I have looked at alternative options.
This is a type of plastic that has two layers. This one I've used was black underneath with a layer of white on top. The top layer can be etched away on the laser cuter to produce interesting effects. Above, I have tried etching away the buttons, showing the black through. I also tried etching the white away to show the black underneath, leaving the buttons white. The second way didn't have as good an effect. It seemed to leave a thin layer of the white, leaving the black looking grey. The first way worked really well and produced just the crisp and neat effect I wanted. This development will definitely improve the aesthetics of the USB and allow me to create a neater finish.
I also had to experiment with different sizes because of the adjustments I made to my sketch in Creo, the wheel wasn't perfectly circle anymore. I cut a few sizes until I found one that fitted securely.
Silicone Casting:
The first photo shows the mould produced by using the 3D printed model. From creating this mould the next stage is to cast it using silicone.
The mould is cut open and the 3D print is taken out, leaving the shape of the lid which is then filled with silicone. The photo below shows my finished, moulded silicon lid.
As this shows, the finished wasn't as perfect as I wanted. Before pouring in the silicone you have to brush on a Vaseline mix to stop the mould sticking. Where I had to mess around with the mould to get air bubbles out it made the silicone become stuck and parts ripped away when I took it out of the mould.
I re-cast the lid that night but unfortunately it didn't come out as I wanted again. There was a slight air bubble at the back and it had got slightly stuck again in the same place as before. I didn't have enough time to do the lid again so i chose to use this one as it sat better on the 3D print bottom.
The bottom of the USB will be kept in the 3D print model. I have primed and sprayed it to get as smooth a finish as possible.
