Repairing 3D Prints with a 3D Pen

It’s been a while since I last played with my 3Doodler Pen to repair a broken 3D print – the results were pretty cool, although it takes some practice to get reasonable results. Check out the post and images here. Some people make pretty amazing sculptures with the pen, however I find the real value in using the pen to fill gaps created by warped 3D prints and fix other cosmetic problems.

One of my latest projects is assembled from 16 separate pieces printed on my Cocoon Create 3D printer (60 hours worth of printing!), and inevitably with such large pieces printed using desktop FDM technology, there are some gaps caused by print warping. Most of them are reasonably small, but some like the ones shown above and below are quite large. Unfortunately the 3Doodler uses 3mm filament, meaning that I couldn’t use the same 1.75mm filament used to print the parts to begin with, but given that this project doesn’t need to be cosmetically pretty (prototype only), a different shade of yellow that came in the box will do.

The first step is of course to use the pen to extrude material into the cavity, ensuring to move slowly and use the hot nozzle to bond the new plastic with the original. It can get a bit messy and smelly (do it in a well ventilated area – I had a fan blowing to keep a lot of the fumes moving away, but there were times my eyes were stinging), and as shown in image 2 above, might look a bit rough, but that’s OK. You can go back over some of the rough patches using the side of the hot nozzle to try and smooth them out, not extruding any material but using the nozzle like a hot rolling pin. This technique is also great for blending some of the sharp edges or smaller gaps that don’t really need to be filled. The final step is to use a metal file to clean things up, giving a much smoother finish.

Admittedly this process wasn’t all smooth sailing, my 3Doodler kept getting clogged despite me taking it apart and cleaning it out – I have a feeling it might be the material quality and/or the temperature of the nozzle not being quite as hot as it needs to be, so a lot of time was wasted trying to manually push the filament through the pen and get a steady flow. I did notice that when I pushed the hot nozzle into my original print (the darker yellow plastic) it melted much quicker than the 3Doodler filament, despite them both being ABS. So material quality is likely the cause. But the final result is worth the pain, gaps are cleaned up nicely and the surface is nice and smooth. Time for some testing!

– Posted by James Novak