Z-seam location

[ignace-de-keyser 1]

Hello,

It has been a while since I have been on the forums, looks like the layout has changed, so i'm not sure if I am at the correct subsection.

I was wondering if there is a way to choose the Z-seam. Instead of placing the Z-seam location inside the print, makeing it invisible, I was wondering if it was possible to explicitly move the Z-seam outside the print. This way the Z-seam would not be part of the printed object. I tend to print Hollow prints, so putting the Z-seam on the insid to obscure it does not really work

[nallath 1,124]

What do you mean by moving it outside of the print? The z-seam needs to be somewhere on the print. We do our best to prevent the effect of the z-seam, but it's not like we choose to create one

[neotko 1,417]

To fix the z mark you need to think like a slicer. How does it happen? Most of the time it's because the z changes without a retraction of the filament and this filament stretch makes some of the filament to follow, then the hotend starts to print making a change on preassure resulting on a z mark. New cura has 'coasting' that if works well it should help. Coasting stops the extrusion X amount before ending a loop, this way there's less filament on the nozzle before changing z and returning to extrude.

The problem with coasting it's that if too much will leave a hole, so it's a value that changes with temp/material/speed.

Other sollution that helps it's to retract before changing the z so there's less filament that can be stretched prior that z move. I don't use cura anymore so I don't know if they did that, but s3d does allow you to activate that option.

Also, since the z change occurs from infill to going to print the interior perimeter line, you could increase the perimeters so that mark its more hidden inside the print.

Other option on s3d it's to randomize the starts/end of each layer loop, this way the z change/resume never happens twice on the same spot.

Edited June 3, 2016 by Guest

[eldrick 65]

Cura has never handled the seam well. If you want to control where it occurs and/or how wide an angle it is randomized over, use Kisslicer instead.

[nallath 1,124]

Cura has never handled the seam well. If you want to control where it occurs and/or how wide an angle it is randomized over, use Kisslicer instead.

 

I guess your information is pretty outdated. Cura 2.1 has a setting called "Z Seam Alignment", which gives you 3 z-seam strategies (of which one is random)

[eldrick 65]

Random is not always a great strategy for the seam, because it leaves blivets/divots all over all the visible parts of a print.

Back is simply silly. Is one supposed to rotate the part on the bed to get the seam where you want it, using Back? Crude.

The real problem with the z-seam is that Ultimaker/Cura pretends that it is invisible, so they have not bothered to implement best practices to manage it. Kisslicer is no longer being developed, but it has the best set of solutions for the seam so far.

Edited June 5, 2016 by Guest

[ignace-de-keyser 1]

Thanks for your replies all!

[nallath 1,124]

The real problem with the z-seam is that Ultimaker/Cura pretends that it is invisible, so they have not bothered to implement best practices to manage it.

 

We don't pretend it's not there, we simply try to prevent it from happening at all. We have a number of strategies in place to prevent the z-seam from having too great of an impact, but most of those are non-user selectable. A number of users have requested a way to select an x-y location to which the z-seam needs to be closest. I'm not sure if we're going to implement that.

[eldrick 65]

The Cura "Random" option is not even remotely random. If you print a small cone with a slow taper (maybe 50mm tall, with a 5mm taper), you will discover that the "random" locations are aligned in quarter- to half-inch-long segments, leaving multiple very visible diagonal scars on the piece. Apparently the "random" location depends on the diameter of the piece, in a very regular way that is not random at all.

So I'll continue using Kisslicer when seam visibility matters.

Edited June 6, 2016 by Guest

[macouno 4]

I Know this is an old thread... But for an art project I am looking to locate the z-seam manually... None of the ways provided in Cura give me any controll. Back is nice... but for large models sometimes I can't vary the orientation of the model.

For instance having a setting that allows me to enter an x and y coordinate and it starts/ends the layer on the nearest point to that location... would help loads!

Is there a place in cura where I can hack this in myself? As a plugin perhaps?

It would be enough if I could change the math behind the "back" function...

Thanks for any help!

[nallath 1,124]

The math of the back function lives in the engine, which doesn't have a plugin structure. The beta has a Z-seam-aligment option, which enables you to select a "user specified" location.