19 Oct

missing layers in prints

I printed out a terrain piece for a friend to use in his Warhammer 40k game. His group was so happy with the print that they told me they would pay for more, so I went looking for more designs that would suit their purpose (technological debris on a sci-fi backdrop).

I found this really nice design of a crashed “killabot” (pictured above) – a robot driven by a race of aliens called Orks.

I priced it at €5.65 – €0.65 for the cost of the filament, and €5 for the time to setup and print it. This is actually quite a ridiculously low number compared to other people that print things professionally (see 3dhubs.com for your local supplier!).

It was going to take about 8 hours to print, according to the slicer program (Cura). I set it to print about 10:30pm.

This morning, I went to check on my 3D printer (an Anet A8), and noticed it was doing something strange at around the 80% mark – some missing layers in a part of the print were leaving obvious bands in the model.

After checking the Layers view of Cura, I saw that what appeared to be a solid model in the default view turns out to have some errors in it that cause Cura to print out some empty layers (pictured below). This is bad, as it can cause later layers to blob.

Cura has a number of built-in mesh fixing algorithms that can be used. It is not always obvious which one (or combination) will fix the problem so you may need to play with it.

In this case, I managed to fix the missing layers by using “Keep disconnected faces”, which is a last resort option. Here’s the fixed view:

I’ve left the faulty print to continue on, because I think the missing layers were few enough that the thing as a whole will still bond together well, but in future, I’ll take a close look of the layers view of a print before I start an 8 hour print…

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