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Be careful with dust filters  

Active Member
Be careful with dust filters

I recently added one of those dust filters that you can open and close to put sponge material in to clean the filament.

Well, it was working ok at first until the sponge material got dragged into the PTFE tube and up to the extruder. Luckily I was able to take the extruder apart and remove the sponge, the PTFE tube did slightly expand towards the end, so I flipped it around that way the narrow side was facing into the extruder.

I definitely checked to make sure the sponge did not have much friction with the filament before using it, seemed to glide along fine. What likely happened is the sponge slid towards the filament opening of the container over time then eventually compressed until there was enough friction for the filament to pull it into the PTFE tube.

I heard some recommendations to add mineral oil to the sponge, but I also heard that this can make layer adhesion weak so I opted to keep the filter dry. Does anyone have a particular filter they use or sponge material that has not resulted in this problem? I used this one from Thingiverse:

Posted : 07/12/2021 7:46 am
Famed Member
RE: Be careful with dust filters

In my book these filters are one of the most useless suggestions floating around on the interwebs. Of course now I'm going to hear from everyone who's a fan of them... But if you store your filament properly, I don't see any point whatsoever in those filters.

Posted : 07/12/2021 9:47 pm
Razor, languer and BogdanH liked
Illustrious Member

@fuchsr I agree.  If your workshop conditions are so bad that filament borne dust is an issue then everything else is going to grind to a halt before you notice.


Posted : 08/12/2021 12:54 am
Reputable Member
RE: Be careful with dust filters

I live in a rural area (i use my home office as printerspace) and i always have airborne dustparticles (old house). Less during winter when the air is dry.

I use a regular paperclip with a folded papertowel to keep most of the particulates out from the hotend.

Prusa Mini+ kit (4.3.4). BondTech extruder.
Prusa MK3S+ kit.

Posted : 08/12/2021 9:11 am
Famed Member
RE: Be careful with dust filters

What @diem said. But you may also consider a reverse bowden setup — run a PTFE tube from the extruder to a dry box.

Posted : 08/12/2021 12:12 pm
Razor liked
New Member

It's good to hear that you were able to fix the issue with your 3D printer's extruder. Adding a dust filter to a 3D printer is a great way to protect the printer's components from damage due to dust and debris. However, as you have experienced, it's important to use the right type of material for the filter to avoid problems like the one you encountered.

When it comes to choosing a suitable material for a dust filter, it's important to consider the properties of the material in relation to the filament being used. The material should not create too much friction with the filament, which can cause it to drag the filter material into the PTFE tube.

One alternative to using sponge material is to use a filter made from a fine mesh or fabric material that is not too dense. This type of material can be less likely to cause friction with the filament, and it is easier to see when it needs to be cleaned or replaced.

Posted : 05/04/2023 9:33 am