Getting rid of z-seam and underextrusion

System

This discussion was created from comments split from: Having Problems Posting?.

Tan Aksoy

hello Samue,

finally made it
here is my problem!

From private message:

now i have a new problem!
the so called Z seam! i just tried to print a big symetrical form very fast so i used 0,3 level height /190°C EX / 50°C Bed/ print speed = 80 / wall speed 60/ retract on layer / 4 Wall lines/ Flow 95 %

now when you look at the pictures you will see that there is some underextrusion going on and that the Layers wont' conect really good. actually looks somehow nice though i really can't stand that Z seams or what ever you would call it. is this a case were the custome firmware would help?


Model: axially symmetric lampe form ( 180mm diameter / 205 mm high/ Wall thigniss 1,6 mm/ no infill) 

adjustments:
Diameter : 1.75 mm
Nozzel : 0,4 mm
layer h: 0,2mm
printing speed : 60 / inner wall 60/ outer wall 30 / travel speed 120
Flow: 100%
material : pla ( renkforce grey) / 190°C extruder / 50°C bed
Retraction enabled : 120 ret. speed / 10 mm ret. distance
hide seam is on too, but with at the corners ... will not work in tjis case ..
but align z seam should have worked...


Results
unregular but constant underextrusions! i had good results with these adjustments before ! not perfect maybe but ok for 0,2 layer high. Now i have constant underextrusions only on one side. It 's the not at the back side where the fan couldn't cool that much.

speculations
i hope it is not something with the axis... i am scared of opening the printer and tearing it apart ... i also have a positive bowing in the middel of the bed ( about 0,2 mm i guess) but i provied the firstlayer with 0,3 mm layer hight and in this case this shouldn't be a problem since the diameter of 180 mm.


Thx a lot for your commitment   

Samuel Pinches

Regarding the Underextrusion:

At 0.3mm layer height, and 60mm/s with a 0.4mm nozzle, there is a lot of plastic being extruded very quickly. I suggest raising the printing temperature 5-10C as the high melt rate will cool the actual nozzle temperature a lot, and 190C is already very cold for the A5.

You may also find improved results by increasing the stepper driver current to help push filament out harder as it gets colder and more difficult to extrude.

Samuel Pinches

Regarding the z seam, there are options in cura to change the layer start position, but there are more options available in other more advanced slicers.

https://m.youtube.com/watch?v=AIU38xp5tis

Samuel Pinches

In this case, custom firmware is unlikely to help with either of these problems.

Samuel Pinches

@Tan Aksoy hopefully you can find this thread ok! I have put it inside the A5 section.

Tan Aksoy

hey ho ,
 something went wrong ... i posted again cause i did not see you message and i was not able to post on the troubleshooting side. how ever i posted here again with new fotos and some adjustment but same results.

 https://jgmakerforum.com/discussion/177/problem-with-big-axially-symmetric-forms-unregular-but-constant-underextrusions#latest

i also raised the temperature to 195 °C before the latest print but than it did not stick to the bed althought i used printafix. but i can try it again with a biger brim. 

Samuel Pinches

For tips with prints sticking, please see the wiki here.

I'm going to merge your other post in here too.

Tan Aksoy

Finally got the outerwalls to be solid .... i tryed 200/205/215 and it would have a little effect but still i always could rip off the outerwall ( see on the picture (215°C)) 
in the End i regonized that when i will tell cura the diameter off the Filament is 1,7 mm instead of 1,75mm the filament flow should will rise ! 
i'don 't know if this is to much cheating but it worked somehow. Maybe you have a better suggestion! i also thing my z axis is ok since the underextrusion happens alway behind or befor the z seam and i now always had it on the otherside.  

Tan Aksoy

at the second picture you see how well the print could be when you look at the left from the z seam...
almost thinking about decreasing the filament diameter to 1,65 mm...
i watched the video though i don't speak spanish and learnd something  and it helped a bit

Tan Aksoy

ok the z seam remains but i changed adjustment again and the outcome will be good from both sides of the z seam .
F-diameter : 1.72
extruder : 210
Shell: outer before inner wall/ optimize wall printing and outerwall wipe distance : 0,2 (was on befor)
wall thigniss: 1.2
inner-/outerwall speed: 60/45
pictures some other time

good night

Samuel Pinches

Sorry - I didn't realise it was in Spanish!! 😂

But there are other videos on youtube about z-seam too.

For 0.2mm layer height, you may want to turn down the acceleration too to help smooth the flow, try and add this to your start gcode, maybe this will help improve your results as such high extrusion rates. I would also suggest trying 220C.

M201 X250 Y250

(more info on M201 here.)

You can also add a little bit of canola oil to the filament at the start, to help lubricate the PTFE tube to reduce friction.