Problems with under extrusion (or that's what I think it is...)

Problems with under extrusion (or that's what I think it is...)  

Active Member

Hello everyone, I need your help to solve the issue that it's driving me crazy. First of all, my experience with 3d printing is poor and the Mini is my first printer.

I have what I believe is an under extrusion problem. I had a lot of troubles printing recently; no matter what, the first layer filament won't stick to  the bed. So I spent two days doing a proper Z adjust until I reduced failures to a 20%. I printed for a couple of weeks, then I started to have troubles again with the first layer.

So I went through the hot end PTFE tube replacement (realizing that the one factory installed was under specs), and another subsequent Z  and also extruder adjustment. After that I have near the 0% of failures. However, I continue to observe that the filament comes out of the nozzle with a certain delay compared to the movement made by the print head. E.g., the first line of filament purged to clean the nozzle: from the parking position (on the right, where the printer awaits for the printing temperature to be reached) the nozzle moves left but the filament comes out way after, almost 3 cm after the nozzle starts to move. 

The funny thing is that the skirt is always printed with no hassle, but when it starts printing the object's first layer, I can observe the same thing.

Just to add more info, I'm unable to print with PLA, which lower temperatures get the under extrusion worse (I think?); I'm printing PETG all the time.

Does anyone knows what my problem is? If  more info is needed, just tell me what you need.

Thank you.

Posted : 23/08/2020 10:04 am
New Member

What temperatures are you using?

With my mini I had a similar problem and after doing a few cold pulls and purging, nothing seemed to help. Later I realized that I had made a temperature tower and set new temp (195C) based on it. Long story short, the temp tower game me a good indication of what to use on the print but those temps were not enough for good bed adhesion, so I went back to higher temps (210C for PLA) on the first layers and my problems are gone.


Hope that helps.

Posted : 01/09/2020 6:26 pm
Active Member


Thank you for your reply. Yours it's a good point, but I don't think it's a temperature matter. Whith no setting changes I'm able to print for a week or two, but then the problem comes again and I have to re-do all sort of actions (cold pull, first layer cal, nozzle cleaning, accurate iron plate cleaning) and then I can start to print again. I don't even know if all those actions are necessary, as I'm quite new to 3d printing. I'm doing all of them and somehow it works, but I'm getting frustrated doing random things hoping in some effect.

By the way I'm speaking to Prusa Tech Assistance of the problem. I'll keep this update if relevant.


Posted : 03/09/2020 1:56 pm

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