Third Time Lucky? - Battledown Flyover

Anycubic Water Washable Resin +

My first attempt at Resin 3D printing this bridge using Anycubic Water Washable Resin + resulted in a very brittle structure that broke apart with the slightest knock.

My second attempt used Nova3D Water Washable Mecha Resin was chosen for its pliablity - a lot more. Firstly, out of the printer it took on a life of its own warping dramatically. I was able to force it back into shape before curing and after that it seemed to hold its form.

After a winter in the garage though I was confronted with this.

Nova 3D Washable Mecha Resin

It had done its warping trick again!

Now, I know I am pushing the technology because there is a lot of long thin plate sections in the bridge design. 3D resin technology is noted for having difficulty with that.

I reworked the design to increase the thickness of plates from 0.33mm to 0.5mm. This may still be too thin. 0.7mm may be adequate but that would not look right in 4mm scale.

I have now chosen Anycubic Water Washable ABS Like 3.0. It is purported to be tough yet still pliable, not as much as the Nova3D, which is very bendy. The first issue I had with the ABS Like resin is that there is no published resin settings that I could find for my Creality Halot Mage 8k printer. That is because the resin is a relatively new product, I believe.

Google AI gave some recommendations, which seem to be the Anycubic resin parameters for their range of printers. I used these and ran a test print using the 'resin xp2 validation' model, which failed badly. I then found compatible settings for the previous Anycubic ABS Like resin (V2) and that gave a good, slightly under exposed, test result. I tweaked the burn time up to 3.5 seconds and test printed again with little difference. Anyway, I decided to stick with this and printed a component for the bridge.

Anycubic Water Washable ABS Like 3.0

The result is encouraging. There was no warp and after curing it held its shape and felt tough with a little pliability. There is some excess resin laid down at the join between crosses and side panels but it is insignificant so, no worries. I'll continue printing more bridge parts and see how it goes.

The reason I want to resin print the bridge is for the high level of detail that the technology provides. There are thousands of rivets in the bridge design that need to be modelled for authenticity. If the bridge fails again then I'll probably scrap this location for a different scene.