Clogged extruders happen. Here are why they happen, how to prevent them and what to do if you have one.
Signs of a clogged nozzle:
Most full blockages will give you an early warning sign by under extruding first, signalling a partial blockage. Sometimes a particle or containment within the filament (guaranteed not to happen with rigid.ink) will lodge in an otherwise clear nozzle causing it to block immediately.
Explanation:
Clogged nozzles can happen due to various reasons. Here’s a list of the most common reasons we’ve experienced:
Either the filament was printed too hot or had the nozzle distance was too close to the bed.
The printer was left sitting idle with a heated nozzle.
Dust & dirt might have been pulled into the now clogged extruder HotEnd.
The filament was contaminated (some cheap stuff is full of things that shouldn’t be in there).
The nozzle has not been regularly cleaned and build up has occurred.
The filament you were previously printing, printed at a very different temperature to the current filament.
Filament material and/or brand is being switched regularly without cleaning in between.
Wood filament was being printed (we’ve had some of the best clogs ever when printing with wood filament!).
How to fix:
Prevention is always better if possible, but not always enough or perhaps it’s too late.
Always check your printer manufacturer’s recommendations first.
Prevent a clogged extruder
Filament can go stale, especially after it absorbs moisture or was exposed to UV/sunlight for quite a while. Generally once exposed to the air, we
Prevent any accumulation in your nozzle by doing pre-emptive maintenance (regularly cleaning).
Use a filament filter. This is a small tool that is used (often clipped on) before the filament feeds through the extruder to filter away anything that may be sitting on the filament (dust/dirt). They can be printed and files are available on websites like thingiverse.
Make sure never to exceed the recommended HotEnd temperature for whatever filament you’re trying to use. Cooked filament blocks nozzles. This includes staying around 10 °C below the glass transition temperature (rigid.ink GT temp available on downloadable datasheets in the settings tab on product pages).
Use particle filled filaments in nozzle with at least 0.5mm diameter or greater.
We recommend FLOSS, a high-performance cleaning filament, to make preventive maintenance easy. Extrude a bit of rigid.ink Floss on a regular basis, such as between material changes and the risk of clogs should be lessened drastically. Especially when switching from a high temp material to a low temp one, or when cleaning up after particle filled filaments.
Unblock a clogged nozzle
You can try to dislodge the block in your nozzle with an acupuncture needle, hypodermic needle or an uncoated high-e guitar string. Once you got the clog dislodged, try cleaning filament (see FLOSS, a high-performance cleaning filament).
A highly effective yet brutal (if done improperly) way to clean a blockage are so call cold pulls or the “atomic method”. We’ve got an article on nozzle cleaning methods here.
Another equally brutal and somewhat dangerous way is to torch your nozzle with a blowtorch (after removing it from the printer first!). The idea is to heat and melt the blockage within the nozzle. This is NOT a method rigid.ink advise for safety reasons.
With ABS you could try to soak it in an acetone bath overnight. The acetone should dissolve the blockage but will only work with materials acetone soluble have been used (rigid.ink ABS, ASA, PMMA, HIPS and Polycarbonate).
You can do the same for PLA with a bath of ethyl acetate.