cleaning nozzles with steel needles?

[aag 6]

Are these things actually useful for unclogging nozzles? Or are they harmful? I am asking because they seem practical, yet there may be a reason why UM does not recommend them.

[yellowshark 153]

Well I have done that a couple of times over the years and it has not caused me a problem. I guess the main point is to scrape off the filament not dig the needle into the nozzle.

[yellowshark 153]

… if you drop the nozzle into some boiling water first you will find that helps.

[aag 6]

Thanks! Are you saying that it is not advisable to pass the needle completely through the nozzle? Even if it is a 0.2mm needle going through a 0.4mm nozzle?

[gr5 2,333]

You can definitely pass through the nozzle but don't go so far that you scratch the teflon which is typically at least 2 nozzle heights away from the tip of the nozzle.

 

These are acupuncture needles.  They have a pointy tip.  I like hypodermic needles a little better as they have a sharp edge and can scrape the inside of the nozzle tip nicely.

 

I have been meaning to cut or grind the tips of my acupuncture needles flat to see if that works better.  Or maybe at a tilt (like hypodermic needles) instead of a point in the center.

 

I find a cold pull is usually good enough for cleaning inside a nozzle but if you have a bit of sand or fiber in there then pushing the blockage up into the heat chamber of the nozzle using a needle followed by a cold pull works great.  But in reality this hasn't been an issue the last few years for me.

 

Another trick for cleaning a nozzle is to burn everything (remove nozzle from printer first of course) over a gas stove.  Don't let the nozzle get red hot.  Just hot enough to produce black smoke.

[yellowshark 153]

No I meant not digging the needle point into to wall of nozzle, you can push it in as far as you want. I have always done it with the extruder removed otherwise you cannot see if there is anything there.

Edited December 24, 2018 by yellowshark

[geert_2 560]

I use a tiny injection needle, of which I cut off the sharp cutter tip, and rounded off the edges. Sharp edges might damage the soft copper or brass of the nozzle. But even then I take care not to apply a sideways load, so I don't wear out the circular nozzle-opening into an oval.

 

Originally the needle was 0.41mm thick, so I sanded it down to 0.39mm, to make it fit into the 0.4mm nozzle opening.

 

This is quite soft steel, and will bend rather than break.

 

[aag 6]

Thank you. This is very useful advice, highly appreciated!