Help Turning point are too thick

[Stoertie 3]

Hi @all,

 

I'm unsing Cura 5.0 (5.1 will be installed this afternoon) fpor my Anycubic I3 Mega S.

 

When I have the problem, that the corners at the outside are thicker than the outside surface of the walls. It looks like as the printer  extrudes too much material while changing direction.

The rest of the printouts is ok for me, only that is no so nice.

 

I'm a little bit in a hurry at the moment, but I can make and post pictures later.

 

Any tipp will be welcome - Many thanks in advance.

 

Regards

Michael

[Stoertie 3]

...sorry, it took some time, but here is a picture of a sample.

 

As you can see in the picture, the corners and also the area where the inner wall touches the outer wall are thicker.

The outer walls of the cube are quite thin (0.8mm) but this phenomenon can also be seen with 2mm thick outer walls.

 

Any ideas?

 

regards

Michael

[Stoertie 3]

it's me again...

Maybe a picture will make my problem clearer. The part is printed with ASA+ on my Anycubic i3 Mega S, sliced with Cura 5.1, layer hight is 0.2

I made the piture below with an usb microscope.

It shows the bottom layer and you can clearly see that the lines at the corners are getting thicker. Also you can see, that the lines od the botten layer, in the left lower corner are not wide enogh to close the plain. The line width is 115% (of 0.37mm with a 0.4mm nozzel) and the flow for the first layer is set to 125%:

 

 

 

 

The second pic shows the corner from the side.

The bottom is 8 layers thick and you can clearly see that only in this area the corners are significantly thicker than above where there are only the 0.8mm thick walls. I think it's no "elaphants-foot" because the first layer is OK and smaller than the 2nd up to 8th:

 

 

Maybe anyone has an idea?

 

regards

Michael

 

[GregValiant 1,318]

Reviewing the gcode for a cube you will find that the "Flow" does not change and (with "Initial Layer Horizontal Expansion" = 0) the Outside Wall Tool path is the same layer-to-layer as the Z rises.  Making adjustments to the Accel and Jerk settings can make a difference as you can have the nozzle spend less time oozing in the corner as it goes around.

 

 

Depending on the printer, Z binding can be a definite problem.  I had to put a .3mm shim behind the Z motor mounting bracket on my Ender 3 Pro to get the Z rod to be exactly vertical no matter where the Z was located.  When I first put it together:  With the print head all the way down, the centerline of the Z motor was not exactly co-linear to the centerline of the brass drive nut on the X beam assembly.  Down low that would cause the brass drive nut to push the threaded rod outboard and that caused a bind.  The shim fixed it.

If you have a single Z drive then the X beam must be perfectly adjusted or the right end will lag behind the movement of the left end (the driven end).  As the Z rises the problem tends to get less and less as the right end sort of catches up.  Using Z-Hops can really point this problem out as the right end of the beam doesn't really react.

Close examination of what the X beam is doing, and making sure the Z wheels are adjusted correctly can fix this.

 

A not-so-popular problem is the coupler on the Z motor rubbing on the Z motor housing because the coupler was mounted too low.  That typically makes for problems all the way up the Z rather than just down low but it's an easy check to make.

 

In your first photo I can see the second layer through the gaps in the skin extrusions.  Not good.  If you have an ABL you might want to consider making an adjustment to your Z offset.  In this case though, I can see a little bit of the second layer extrusions and they also appear to be very "round".  You might have some under-extrusion going on.  Skins are always best for checking for over or under extrusion.

 

 

 

[Stoertie 3]

Hi Greg,

 

thanks a lot for your answers.

 

18 hours ago, GregValiant said:

Reviewing the gcode for a cube you will find that the "Flow" does not change and (with "Initial Layer Horizontal Expansion" = 0) the Outside Wall Tool path is the same layer-to-layer as the Z rises.  Making adjustments to the Accel and Jerk settings can make a difference as you can have the nozzle spend less time oozing in the corner as it goes around.

 

That an idea, I will try to adjust. I think at the corners it looks like an over extruding when the nozzel makes an direction change near to 90° (sharp corners) to increase the mooving speed of the hotend meight be a soloution.

 

I will check the mechanical things later at my leisure.

 

 

18 hours ago, GregValiant said:

In your first photo I can see the second layer through the gaps in the skin extrusions.  Not good.  If you have an ABL you might want to consider making an adjustment to your Z offset.  In this case though, I can see a little bit of the second layer extrusions and they also appear to be very "round".  You might have some under-extrusion going on.  Skins are always best for checking for over or under extrusion.

 

I already checkt and adjust the feeder, its settings are OK. Also the distance between nozzel and printbed ist perfect (checked and adjusted with a sheet of paper)

With the cura setting for line width at the first layer I already reached 150% and the flow for the first layer ist also set at 150%

 

One short question to the cura settings... Do you know what happend when a Cura input field gets a yellow background? (for example when I set the flow to 160%)

 

Is this change of color only a warning or will Cura ignore the yellow setting and work with highest possible setting?

 

regards

Michael

[ahoeben 1,965]

Orange means a warning (where Cura thinks the value may be "unreasonable", but uses it as you entered it).
Red means an error (where Cura thinks it is impossible to do that and refuses to slice, eg when you set the layer height to 0).

[GregValiant 1,318]

"With the cura setting for line width at the first layer I already reached 150% and the flow for the first layer is also set at 150%."

The line width increases the "Flow Rate" through the nozzle, but not the ratio of "Volume of Filament IN : Volume of Extrusion OUT.  Increasing the Material setting "Initial Layer Flow" does change that.  150% is indicating to me that there is a problem.

Calculating the volume of filament required to make an extrusion 100mm long is an easy thing to do.  Cura knows your filament diameter so it knows the volume of 1mm of filament.  It knows the Layer Height and Line Width so it knows the volume of a 1mm extrusion.  A cube 10 x 10 x 10 will require 1000mm³.  Having to increase the flow to 150% means you are telling Cura put 1500mm³ into that same cube.  Something isn't right.  You didn't happen to use one of those "single wall" or "double wall" calibration cubes to calculate your E-steps did you?

 

Load a simple Caliibration Cube into Cura and set Cura up to slice with your regular settings.  Use the "File | Save Project" command and post the 3mf file here.

This is at .4 line width and 100% flow on my Ender.  I level with a piece of parchment paper.

E-steps are at 97 and when I ask for 100mm of filament that's exactly how much pushes through the extruder.  The filament measures 1.72mm in diameter and that is what I've entered into Cura.

There is some "push" in one corner.  That's where the z seam happens to be.  The extrusions are nicely welded together.

 

[Stoertie 3]

Hello,

 

i adjusted the E-Steps a second time. Strangely, it only carried 95mm instead of the required 100mm.
Now I have printed my test object again with slightly adjusted parameters (110% line thickness and 110% flow) the bottom layer already looks much better.

 

 

 

Likewise, the thickening on the outside in the area of the bottom (8 layers thick/high) has already become somewhat smaller, but is still present.

However, the dimensions match the 3D model almost 100%. The rest should be fine tuning and I should be able to manage that.

 

Thank you very much for your help, you have brought me in the right direction.

 

Many greetings
Michael