Overextrusion after internal top layers
Good afternoon, there is some serious problem with overextrusion of the upper layers using PrusaSlicer, in fact, as I understand it, the slicer makes a supposedly thick layer of infill, stretches bridges over the infill. With a layer of 0.2mm, the layer of bridges is 0.57mm, but the problem is that my layer is applied perfectly horizontally and without sagging. As a result, the next layer of solid filling is printed with overextrusion and this parameter accumulates.
The extruder is calibrated, the plastic is also normal.
34 Replies
unwilling-turquoise•9mo ago
0.6 nozzle 0.2 lr
afraid-scarlet•9mo ago
What does a 30mm x 30mm x 3mm high cube with 0.2mm layer height, 2 bottom layers, 10 top layers look like?
This would give us a baseline for comparison.
unwilling-turquoise•9mo ago
I tried this and that, I thought that the problem was in the compensation of the bad mesh, but it seems not. Very strange behavior. Actually red - a perfect square 250x250mm and 2 layers of the bottom. Everything is smooth and perfect, I run printer with the same settings on a butch of other parts, but put 4 bottom layers, turn on the filling. and on the 2-3rd layer the crap begins.
unwilling-turquoise•9mo ago
unwilling-turquoise•9mo ago
unwilling-turquoise•9mo ago
unwilling-turquoise•9mo ago
Tomorrow I'll try to print a 250x250 square again. But on black ABS.
afraid-scarlet•9mo ago
Black appears to be the problem color. But rather than a 250mm square can you print the square I suggested up there 👆? It’ll be much faster to print.
Seeing the giant red square comes out fine, I don’t think there’s a bed mesh or other mechanical issue. That leaves the filament. A small square will help determine if it’s a extrusion multiplier problem or not.
unwilling-turquoise•9mo ago
It’s just that before this, a 200x200 square was printed at the edges like a very high offset, and it was too close to the center that the layer was translucent. But at this size, the unevenness of the table is not so visible. Sorry I didn't take a photo.
Tomorrow i'll do new 
unwilling-turquoise•9mo ago
unwilling-turquoise•9mo ago
It looks as if during printing it raised the table closer to the nozzle, while everything is ok along the perimeters
afraid-scarlet•9mo ago
What does the bed need look like?
is this enclosed? If so, are you letting it heat soak before starting the print? If so, how long are you letting it heat soak?
unwilling-turquoise•9mo ago
I tried it now both with the enclosure open and with the enclosure closed, the result is the same. I don't understand what the hell is going on.
unwilling-turquoise•9mo ago
unwilling-turquoise•9mo ago
So, black and red one, the same file. I thought that problem in material, but.... seems not
unwilling-turquoise•9mo ago
Again, I now tried to print the same large square in black ABS, the same file as in red - again problems.
unwilling-turquoise•9mo ago
Perimeters was perfect, At first it was also printed perfectly in the corner, but then it was as if the extrusion ratio changed and a severe overextrusion began. The filament was measured - everything was within the normal range of 1.74-1.75, no more, no less.
Now I have rebooted the printer and am trying the small red square again.
Now I have rebooted the printer and am trying the small red square again.
Aaand... everything is almost perfect.
unwilling-turquoise•9mo ago
unwilling-turquoise•9mo ago
you didn't answer my other questions. Are you heat soaking? And if so, for how long?
unwilling-turquoise•9mo ago
What do you mean by heat soaking, how long do I allow for the table to heat up? Or so that the air in the chamber warms up?
do you turn on the bed to temp, wait 30 or more minutes, and then start a print?
as things heat up, they move which is causing your problems
unwilling-turquoise•9mo ago
I wait 10 minutes on average, in principle, when I print parts, I wait longer. Now I have been doing only tests for 3-4 days. I measured it with a thermal imager, in principle, everything is more or less good.
your smaller cube is working because it is small and things haven't moved much by the time it is done the first layer
10 minutes is not enough. You can see the changes that another person measured on his vcore
https://www.printables.com/model/230716-ratrig-v-core-3-extrusionless-x-gantry-mod#preview-images
Printables.com
RatRig v-core 3 extrusionless x-gantry mod by elcojacobs | Download...
V-core 3 mod to remove the aluminium extrusion from the x-gantry and run on just the rail or a top and bottom rail | Download free 3D printable STL models
as you can see from the graph it takes about 50 minutes
unwilling-turquoise•9mo ago
The problem is that overextrusion occurs even after several hours, for example when printing a large cylinder
There is no overextrusion on the perimeters, for some reason only on the solid filling.
For example, the big black was printed right after the red one. On red everything is ok, on black there is a huge overextrusion. I thought that was filament problem, but it's not
unwilling-turquoise•9mo ago
unwilling-turquoise•9mo ago
Now I’ll warm up the table for half an hour, then I’ll start printing again. See what happens
Everything is fine, but it is not clear why ABS is overextruded. Now I set the extrusion coefficient to 0.9, and visually everything is fine now. Now I'll try it on PLA
unwilling-turquoise•9mo ago
unwilling-turquoise•9mo ago
May be a bit overextruded
unwilling-turquoise•9mo ago
So PLA at 1 extrusion rate, and 0.9
unwilling-turquoise•9mo ago
essentially extremely strange, because... The rotation distance is, in principle, precisely calibrated.
Another update to the problem: the more models on the table, the greater the overextrusion. If you print 1 part, everything is basically fine, but if you print 4 models, everything gets worse.
Ok. I found the root of all problems. That was RAPIDO week of checks. And the problem turned out to be quite simple. The answer to everything is Rapido Hotend.
The bolts on the Rapido ended up loosening again, the block moved up and down, rose up during retracts, and dropped down when printing large surfaces. At the same time, he didn’t stagger too much.
Plus, the thermal barrier tube rolled inward, so that the diameter of the upper neck of the tube decreased, as a result, the heating block moved back and forth due to the while I was repairing everything, I think I damaged the PT1000 x) Although I hope it’s just the connector that fell off.
week of checks. And the problem turned out to be quite simple. The answer to everything is Rapido Hotend.
The bolts on the Rapido ended up loosening again, the block moved up and down, rose up during retracts, and dropped down when printing large surfaces. At the same time, he didn’t stagger too much.
Plus, the thermal barrier tube rolled inward, so that the diameter of the upper neck of the tube decreased, as a result, the heating block moved back and forth due to the while I was repairing everything, I think I damaged the PT1000 x) Although I hope it’s just the connector that fell off.