As a product designer I work on a whole range of different products in different sectors and so when we took delivery of the new Autodesk Ember 3D printer I was excited to see what it can do. Currently we also have a Makerbot 2X which is great for printing larger parts but it not really suitable for small-detailed parts. One of the first products I printed on the Ember was the components for a new medical device, the quality was excellent, the parts were threaded and the threads worked really well. However, one thing that was missing was colour. On the Makerbot we have a whole range of colour spools to choose from, but with Ember we only have the standard clear resin. There are black and grey resins available but they are pretty boring and on this particular device I wanted to differentiate the parts to see their function better.
Step 1: I Wonder If This Will Work?
When I started to think about colouring the resin I made the assumption that any colour would need to be oil-based, not water-based. We happen to have been working on a small device for printing a logo on golf balls....(its quite cool, take a look - http://www.mygolfid.co.uk/golf ) as part of this we spent a lot of time sourcing suitable inks that dried quickly, so I figured, lets try some of that! My main concerns (not being a chemist) were would the pigment mess with the chemicals in the resin so that it wouldn't cure, or would the pigment actually block the UV light and so stop the resin curing in that way.
With this is mind I decided to start by just adding 1 or 2 drops on black pigment to 75ml of resin to see what would happen....
Step 2: Wow...it Does Work!
.....the anticipation of waiting for the first print to emerge from the resin tray was pretty exciting. The first thing I noticed as I watched the rotating tray was that yes, it was printing something, secondly because the print was so glossy and shiny I was convinced it was still transparent, only when I opened the door I realised the colour has held! Much excitement in the studio followed and then more anticipation as we rinsed the part in alcohol, the colour held.
To be honest the result was better than expected, the part was not black but more of an indigo blue, but this was from only 1-2 drops of pigment.
Step 3: Lets Try Some More Colours
Unfortunately I only had black ink on hand so I had to wait a few days for more ink to arrived before I could do further tests. Next I tested red pigment, with only 2 drops of pigment the resin was quite a pale orange, a nice colour but not red. I ran it again with a new mixture that had around 10 drops of pigment, that came out in a darker almost fluorescent orange, a very nice colour, but still not red. I think this may be due to the base resin having a slightly blue tint to it and also I probably need to find a deeper red pigment. Blue & green followed and these look great too, all the colours are very vibrant and I'm sure that with a bit more mixing and testing different colours can be achieved.
One thing to note, on the orange part with around 10 drops of pigment the finished part seemed a little softer than the others. This is a characteristic that I may investigate further as it could actually be a useful way of making semi-flexible resins...but that's another post!
Step 4: Whats in the Mix?
So here's the bits you need:
Standard Autodesk P48 Resin
Norris #199 ink - its around £15 in the UK (US$20) but you only need a few drops so it will last for ages
Spare bottles to store your coloured resins
Give it a go and see what colours you can come up with, suddenly printing on the Ember became even more exciting!