Cura 2.5 z-seam problems, suggestions please?

[txesc 1]

I'm having trouble with the newer Curas and reducing the seam,  I'm getting major scarring on round models - tubes, curves etc.  I used to print similar models without this problem.

I've been trying the usual solutions - slowing down, adjusting the acceleration, temperature, adjusting retraction, even different materials...  

I've not been printing much lately so have found it challenging to keep up with the changes in the latest versions of Cura (not complaining! I really like a lot of the new features that I've touched so far).

So my question is what else effects the seam when slicing and how have the calculations changed from older versions, if they have?  

It's definitely seems to be happening at the slicing stage and not a printer problem; I've tried on two kinds of printer (ultimaker 2 and i3) and both have the same issue.  

Cheers!

Edited May 5, 2017 by Guest

[XYZDesignPro 70]

In the later versions of Cura under the Shell settings there is Outer Wall Wipe Distance.  By default the setting is 0.2mm.  It's purpose is to attempt to better hide the Z scar.  In practice, I find in many cases it's better set to 0mm, as the default 0.2mm tends to make the scar wider.

Also, you can explore the Experimental section of the settings menu and enable Coasting.

Have you tried locating the Z scar at a specific location?  This is also found under the Shell settings as Z seam Alignment.  I find putting the Z scar in the corner of a part, or along a sharp radius, helps hide it quite well.

Edited May 5, 2017 by Guest

[txesc 1]

thanks XYZ.  I'll give the wipe distance a go.

Moving the scar is useful but unfortunately I don't have any corners on these models.

Coasting's handy but I find it creates discolouring which draws the eye, although it is a time saver on prints that are finished properly.

Do you know if there's any advantage to separating where the layer starts and seam alignment? They are two options now.

Edited May 5, 2017 by Guest

[XYZDesignPro 70]

thanks XYZ.  I'll give the wipe distance a go.

Moving the scar is useful but unfortunately I don't have any corners on these models.

Coasting handy but I find it creates discolouring which draws the eye, although it is a time saver on prints that I finish properly.

Do you know if there's any advantage to separating where the layer starts and seam alignment? They are two options now.

 

Putting the Layer Start and the Z seam at the same co-ordinates significantly reduces the travel moves in a hollow part, as can be seen by the blue lines shown in the Layer View. In a large print, this can reduce the overall print time.

BTW, I find that 2.4 typically has shorter print times than 2.5 on exactly the same part with the same settings. While I really like some of the new features in 2.5, I'm using 2.4 for my daily work.

One last thing. I'm using a 0.6mm nozzle (3DSolex). I have found that the thicker wall is more forgiving of the Z scar. Two outer walls = 1.2mm vs. 3 thinner .4mm outer walls = 1.2mm.

[txesc 1]

Thanks for tips!

As for layer start vs seam, why would you want to separate them?

[XYZDesignPro 70]

Thanks for tips!

As for layer start vs seam, why would you want to separate them?

 

If you specify the Z seam in Cura 2.5 it will not automatically assign the same location to the start location. It always defaults the layer start location to the upper right quadrant of the build plate. Try it and I think you'll see what I mean. Then re-locate the layer start to the same as the Z and notice the difference in the blue lines of travel moves . . .

[txesc 1]

Tweaking 2.4/5 settings so far has only been able to minimise it.

It looks like it's underextruding the last part of the path to compensate for potential build up, perhaps? This is even with coasting/combing/retract on layer change off. Perimeters first or infill first has relatively no effect. The seam is generally embossed rather than building up as I've experienced in the past.

Strangely enough, the same models sliced with Cura 15.4.6 don't have a seam at all...

So short term it's sorted I guess, although the prints are losing out on the quality and feature gains of the newer versions of the slicer.