Differences between v2.7 & v3.3.1

[Cminer 0]

I printed these with v3.3.1 and it has flaws in the print. I tried two different color materials and both have this problem when using v3.3.1.  When I switched to v2.7 it printed perfectly in both colors. The picture with the red and green, the red shows the flaws.  On the picture of the two green parts, the full size is v2.7 and the short one is v3.3.1.  You can see the same flaw in the short green as the tall red.

 

What could the difference be in v3.3.1 or any ideas what is causing the problem.  It looks like a retraction problem on the red part but I lowered the retraction from stock at 0.8mm to 0.5mm and it didn't help.

[gr5 2,265]

Make sure "retract at layer change" is turned off.  That's the first thing that comes to mind when I look at that photo.  Also look at all the speeds (there's something like 6 printing speeds) in 2.7 versus 3.3.  

 

Also look at line widths.  It could be that the outer most shell is a different line width than whatever prints immediately before.  I prefer to make all the line widths the same for the most part.

[Cminer 0]

I verified the "retract at layer change" is turned off in v3.3.1 and v2.7.  Outer wall line width in both versions set the same at 0.4mm. Pulled up all the retraction settings in both versions and they are the same as far as I can tell. I'll have to check all the speeds.

[burtoogle 516]

Hi, is it possible to post the 3.3.1 project please? I would like to take a look at it. Thanks.

[Cminer 0]

I've never uploaded a project before. Hope it's right.
 

Test-Hood-cura331.curaproject.3mf

[burtoogle 516]

Thanks for the project, a couple of things I think you should change are:

 

1 - enable the wall order optimization

 

2 - specify a z-seam alignment position, the actual position doesn't much matter but it will force the z-seams to align which often looks best (or not!)

 

These changes will reduce the amount of travel between printing the outer and inner walls which is probably what's going wrong as the long travels let the nozzle dribble and so by the time it gets to print the outside wall it will tend to underextrude.

 

Also, I think to get the nicest looking z-seam, use the same speed for the outer and inner walls because that will avoid a step change in extrusion rate when an inner wall finishes and the outer wall starts.

 

Hope this helps.

 

[Ricky 5]

@smartavionics

I doubt that z-seam setting hide the truth cause of the problem. For the spiral object like tower, 3.31 always delivered sub par path planning compared to 15.04.

 

I just found another case in MP select mini Facebook group.  You can see the obvious z-seam in the inside wall (Please disregard the wall form outside. There is wavy issue. It might be caused by its bent Z threaded rod).

Picture a2.jpg is G code from 3.31, while a3.jpg is G code from 15.04. 

[Cminer 0]

On 5/21/2018 at 3:01 PM, smartavionics said:

Thanks for the project, a couple of things I think you should change are:

 

1 - enable the wall order optimization

 

2 - specify a z-seam alignment position, the actual position doesn't much matter but it will force the z-seams to align which often looks best (or not!)

 

These changes will reduce the amount of travel between printing the outer and inner walls which is probably what's going wrong as the long travels let the nozzle dribble and so by the time it gets to print the outside wall it will tend to underextrude.

 

Also, I think to get the nicest looking z-seam, use the same speed for the outer and inner walls because that will avoid a step change in extrusion rate when an inner wall finishes and the outer wall starts.

 

Hope this helps.

 

 

Thanks for this information. This was a big improvement in the print. It's not quite perfect but I don't know if I'll ever achieve that.

 

The underextrusion look is now gone. The Z seam is all in the same place and It has a slight bump there.  Any tweaks to make the z seam bump a little better or smaller?

[burtoogle 516]

Hi @Cminer, thanks for the feedback. Tricky with a cylinder because you can't hide the seam on an edge. Perhaps you can improve it by tweaking temp/speed/retraction amount/etc. Let's be honest, it's never going to be completely invisible but you should be able to manage something at least as good as this example I just picked at random from a pile of test prints.

 

[Cminer 0]

My print is actually a bit better than that now. I guess I should be happy with what I have.  I may still do some tweaking tests and see if I can improve it.