In mid October I blogged that I had built Firefly, but I expressed dissatisfaction with the build quality. I was mainly unhappy with the standard and longevity of the paint. It seems to me that some paint colours take better on 3D prints than others; the dark grey of the hull looks fine, but the yellow shows up lots of imperfections. Of which, there were quite a few.
In this first iteration of the design, I made the entire cab from vacuum formed, clear PET-G. I then sprayed some of it yellow, to look like bodywork. This was the paint that flaked off during Sidmouth Science Festival; I guess acrylic paint doesn’t stick to (rather flexible) PET-G all that well.
To get the shape of the cab correct (which was necessary to fit the parts inside it), I was forced to heat up the PET-G a lot and apply vacuum for a long time. This made the part the right shape, but also picked up the layers in the 3D printed mould. This made the “glass” frosted and it meant that I wasn’t able to get a nice crisp line between the bits I wanted clear, and the bits I wanted yellow.
I printed most of the robot from white PLA then sprayed it with the same paint so that the robot would have a consistent colour. However, I found that the colour of the paint was not consistent across different components; perhaps different print directions look different, perhaps my lack of preparation of the parts prior to painting showed through, or perhaps I’m just rubbish at painting.
Basically, I was unhappy… So, I rebuilt it.
I reworked the cab so that the glass was vacuum formed PET-G but the bodywork was 3D printed from PLA. Since the yellow bit wouldn’t need to be painted, I was able to print the cab, and therefore the rest of the robot in yellow PLA. This has resulted in a much neater, consistently coloured, build.
There are loads more decorative parts to make, but the machine is basically ready for the game specific stages of development. In other words, I can get on with the core of the work and stop messing about with making things look pretty.
However, while we’re here I’ll point out the rather nice shiny hydraulic rams on the bulldozer blade. I had planned to use some stainless-steel rod, but it was going to cost a fortune. Then I found some stainless-steel drinking straws on Amazon for about £4!
If you’d like to know more about how Firefire was made, take a look here.
Team PiDrogen 