Using Cura vs Pronterface: randomsing layer staring position?

Hi,

I'm testing prints with Cura. I've been using calibration hollow cube example for testing birding, which fails with Slic3r http://reprap.org/wiki/Calibration#Bridging

The result can be seen here (left is Cura, right is Slic3r with Pronterface): [imgur.com]

The result is much more detailed with Cura because it uses 0.2mm layer thickness, and the bridging works, where it fails with Slic3r.

But as you can see on the picture, the edges of the cube are pretty bad with Cura, and I suspect it is because it doesn't randomise the printing position start for each layer.

Has anyone been able to calibrate this with Cura?

Can you post which versions of each software you are using?

I think cura is a front-end too, it uses skeinforge for slicing. But there are a lot of settings to this thing, so is it really a one-to-one comparison?

look at settings for cura. reduce packing density from 1.00 to a lower value such as 0.95. reduce in increments until part no longer bulges. if inner and outer perimeter no longer touch then you should also slightly decrease nozzle size from advanced menu.


cura works great out of the box. probably your packing density will fix it right up.

I've been using lastest available version of each software. Cura 13.03 and Pronterface with 0.9.8 Slic3r.

I'm unsure but it doesn't look like Cura is using skeinforge, the slicing result is very different between the 2 softwares for this bridging test.

And indeed, this is causing the problem with Cura: the slicing doesn't seem appropriate for a cube perimeter. It is on the other end perfect with Slic3r, including the corners.
The hothead even does a specific additional move to reinforce the corner (only on 2 of the 4 corners though).

The corners all have problems with Cura, there's all not very square, as if there were a lack of material.

My packing density is already down to 0.85, as advise by Cura for ABS printing. I'm including the Cura profile I use, ABS.ini, as well as the config.ini from Slic3r.

Hope someone can make sense of these.

Edited 1 time(s). Last edit at 04/03/2013 10:27PM by coolnodje.

in slic3r reduce bridge speed from 60 to 30. change bridge flow rate from 1 to 1.2 this should help get the bridge going across the top. you cant squish layers with bridge you can only stretch. but there is a limit, and thickness is about the diameter of the nozzle.


in cura: reduce retraction speed from 40, to say 15. i bet motor is skipping instead of retracting.

Thanks for your advice James.

In slic3r, I have reduced bridge speed to 30 and increased flow ratio to 1.2 (don't understand how this one influence the print actually), and the result is a bit better, but still not acceptable.
It seems the problem comes from the bridge structure not really sticking to the perimeter at first, making the root drops at some point.

As for Cura, reducing retractation speed doesn't seem to be appropriate,. This setting is only used when the head travels without printing, which is not the case on s simple cube.
I'm still not able to get a proper perimeter. It starts right from the first layers above the bottom, the corners are not flat, and it influences all the coming layers.

in that case perhaps decreasing the nozzle size, it will cause the perimeters to overlap, and should help with bridging as well. you may want to slow down your print speed further overall, or increase your abs temp.