Zipper Line

[jameshs 42]

I could not find this with a search - is there a setting in cura that randomises the zipper line - spiralise?

I am getting an obvious zipper line and thought I read of a setting to get rid of it?

Thanks

James

 

[Dim3nsioneer 557]

The issue you are referring to is called 'z-scar'. It's (unfortunately) a speciality of Cura. There are numberous posts about it in this forum. You best find them by googling "z scar site:umforum.ultimaker.com". Forget the search function of the forum; it's just crap...

To make it short: the z-scar is there for the time being and nobody knows if Daid will and can do something sustainable against it soon. One reason is the fact that there are patents protecting algorithms which cover this seam and produce seamless prints.

Daid recently offered the possibility to randomize the spot. Most probably he will answer to your question when he reads it.

If you want to get rid of it right now you have to use a different slicer than Cura.

 

[gr5 2,003]

You can get rid of it by simply printing slower. The problem is that extrusion needs to stop while moving Z but it never really stops. But if you print slower then the pressure is lower. At 20mm/sec it mostly disappears. It also helps to increase Z acceleration because then the Z moves much faster. You can make the Z move so fast it's almost a click.

Then there is also the "spiralize" feeature in Cura but that is very specialized and only works on a tiny tiny subset of models. Mostly cups and vases that have a solid interior but you want to print single-pass wall thickness.

 

[jameshs 42]

brilliant - thanks - I knew Z was in there somewhere so will have a look in and play a bit more. The model I am using is already at 30mm/s and may be a 'production' run so I will try to optimise without speed first.

Does slicing the model in different bed orientations make a difference to where cura places the z scar - I currently orient the model for best cooling, but could to a 180 degree and then the z-scar would be in the back, or is the slicer to spart for that

James

 

[anon4321 16]

See this for information on Z speed. I couldn't reach the numbers Illuminarti did. I think I'm running 1200 and 40.

 

[illuminarti 18]

As a practical matter, it's very hard to predict or control where Cura will put the z-scar, and it tends to move around in odd ways too. When I was working on the second generation extrusion test models, I actually just gave up and switched to another slicer.

I think that Kisslicer and/or Slic3r give you some control over the start point, but I haven't used those in a while. I've actually ended up using the commercial package, Simplify3D, which lets you specify the orientation of the z-scar, or chose to have it randomized, or simply wherever makes the toolpath quickest (as Cura does).

 

[illuminarti 18]

I think this is the link anon was going for:

http://www.extrudable.me/2013/04/02/the-myth-of-z-speed/

 

[anon4321 16]

Yes, thanks. Stupid IE sometimes won't paste links in this forum....

 

[Nicolinux 288]

@illuminarti: What do you think about Simplify3D? I found this thread and it doesn't sound bad (http://umforum.ultimaker.com/index.php?/topic/3876-u2-with-simplify3d/).

Maybe it is time for another cool blog post