Dan's 3D printing

Despite my efforts at winterproofing my printer I ended up taking a five month gap in 3D printing. The printer was workable, but I didn’t particularly have anything I wanted to print so I took a break and before I knew it time had flown by.

I wanted to print and paint another 75mm mini as a palette cleanser so I decided to get the printer up and running again.

That’s when the problem started. I had failed prints for about two weeks straight, running one or two prints per day. You can see the sorts of failures I was getting in the picture above. The scaffold would print fine, and perhaps a few of the finer elements would print, but the main bulk of the model would always break off at some point and remain stuck to the FEP film in the printer.

I tried dialling up the exposure time, changing the FEP film, switching to a new bottle of resin, and re-orientating the model. Eventually I got the model I wanted to print with the perfect angle in the printer, but as soon as I tried the next model I was back to square one.

In the end I solved the problem. While researching these types of failure I read that using old resin (either a bottle left open over six months or one past its expiry date) could be a problem. I had discounted this since I’d opened a fresh bottle that was in date and it had not helped. However, the resin I used to begin with (which I had opened in December) and the new one were both from the same batch and due to expire in a month or two. When I switched to another bottle I opened in December but that had over a year to go before expiry suddenly every print started working again.

My conclusion is that having a bottle open for six months isn’t necessarily a problem, but as resin approaches its expiry date the “sweet spot” for getting prints to work gets smaller and smaller. You might be able to get it to work if your scaffold design and orientation is perfect, but it will be easier if you use a fresher resin.