Had a quick look at the gcode nothing glaringling obvious, the reason I was suggesting something mechanical rather than cooling or setting related is just because of the localisation of the problem, it doesn’t appear to be at the beginning or end of a tool path either. When you say this happened at two points, at different heights, were they in roughly the same location in x-y?
The hottend is moving freely… there’s nothing snagging, restricting the bowden tube at a certain point / extreme is there?
Regarding point 1; Even cheap filament can look great but what you don’t see if it has diameter tolerance issues. Therefore you would have to measure it at several points on the spool with a caliper. So you can never say that filament is fine just by looking at it (even new spools). If you need help how to properly measure I can give some more info.
If you havent gotten any problems with the same spool and different prints then we can just move forward to solve your issue.
P.s. your retraction speed seems a bit aggressive but i’m not sure what the standard is for the 2+
Seems unlikely to be a filament issue doesn’t it? What’s the odds on the filament having an issue at exactly the same section of the print for what must be about 100 layers? If I’ve had an under extrusion issue because of inconsistent filament is usually just drops a layer.
Oh it’s just an extra check to make sure that there’s no issues at all with the filament but I agree that this is not going to solve the issues alone :). I work in the filament industry so I kinda have a standard list of like 30 points that I work through group-wise to pin down where the issues are.
This is an error in your retraction or pausing when you change layers. That is why it is occuring at the same area on the print, because that is where the zaxis is moving up. This is also why the error is occuring elsewhere on the print, but NOT in the same layers.
One of two things.
1. Your layer height retraction number is screwy. You are retracting so far that the head moves up, the next layer starts, but it takes awhile for the plastic to get out of the extruder.
2. Or more likely, you have a mechanical issue. The extruder pauses, the z axis moves up to the next layer, and when the extruder unpauses, it is slipping, jamming, etc. As more and more plastic is pushed into the extruder, it finally builds up enough push to continue printing.
3. This could also be caused by a worn, difigured, burned PTFE extruder lining, that it needs much pressure to get going after a pause, zaxis move.
All the other temperature, speed, gust of wind, etc. posts are simply not realistic.
I will bet you a candy bar that if you watch the print as it is happening, it will be exactly where you printer is changing layer height.
Agree with everything here, but when I looked at the gcode for the area of the problem, the layer height appears to change at a different position for each layer???
Thanks for your answer. On Monday, I’ll check if there is any mechanical issue with the printer but I’d say that the printer is working smoothly. I’ll also try to run again the same gcode file, in order to understand if the problem is due to an external factor or to a problem in the code/printer/material.
