Cura wall thickness adding hatching where there should be a line.

[BillieRuben 0]

Hi folks! 

I have made a super simple box, and I want the outer walls to be 3 lines thick, e.g. 1.2mm using a 0.4mm nozzle. 

I've set this all up in fusion fine with parameters. However, when I import it into Cura and slice it, it hatches the middle, rather than adding a solid line:

The hatching is problematic for many reasons;

• it shakes the printer, working things loose
• it's noisy
• it reduces the structural integrity of the print
• it takes longer to print
• wears motors
• makes it harder to achieve a waterproof part. 

I tried changing the walls to 1.201 in fusion and it works fine now, but now it makes it harder to design my part. 

This is what I think it should do if I set it to 1.2mm: 

I thought I'd raise it, because  I remember in previous versions of Cura it would add a line, even when one wouldn't technically fit (it would compensate flow according to the gap), I much preferred this method to the weird hatching, but it seems to not do this, anymore.

Is this something I can change in the settings? 

[BillieRuben 0]

Anyone know any settings I can change so it prioritises long lines instead of hatching?

[DivingDuck 105]

Had you already try to check -->Shell ->Print thin walls?

 

An other way is (depending on your actual setup) to reduce line width in -->Quality -->Line Width a little, eg 0.399 fore a 0.4 nozzle depending on wall the thickness you need.

[BillieRuben 0]

Hi Diving,
thanks for the stab, unfortunately the print thin walls setting provided no change. 

I'm very reluctant to go messing with the wall width given that will effect many other settings and the dimensional accuracy of the final print. 

I know Cura used to slice things using lines of varying thickness, instead of this hatching, I just want it to go back to that. 

I just spend the last two days trying a certain tiny print with fine details (that I can't add a brim to) that keeps being shaken free from the build plate with this hatching. 

Can any of the devs weigh in? Is there a way to switch this back to the previous slicing way? 

[burtoogle 514]

This is caused by the fill gaps between walls feature. Some versions of cura behave better in regard to this feature so it's worth using a recent release (say 4 or greater). Even better, you can use one of my cura builds (Linux or Windows only) and they use a completely different implementation for the wall gap filling and thin walls which do not produce the zillions of little lines. You can find my releases at https://www.dropbox.com/sh/s43vqzmi4d2bqe2/AAADdYdSu9iwcKa0Knqgurm4a?dl=0

. My releases also feature quite a few other bug fixes and improvements (IMHO) compared to the Ultimaker releases.

[DivingDuck 105]

5 hours ago, BillieRuben said:

I'm very reluctant to go messing with the wall width given that will effect many other settings and the dimensional accuracy of the final print.

 

The dimensional accuracy wasn't a problem for my mainly technical prints. In FDM a thou in millimeter isn't a real problem as we are talking here about 0.1 mm for a standard nozzle (not to mention a differnet shrinkage in x,y, z for filaments for a print). FDM shouldn't be the technology to go for you if you need this kind of accuracy.

 

5 hours ago, BillieRuben said:

I know Cura used to slice things using lines of varying thickness, instead of this hatching, I just want it to go back to that.

Varying thickness can help but isn't the answer for all possible accruing problems. This is why we need to manipulate setup parameters finding the optimal solution between printability, stiffness, accuracy and print time for technical prints. There isn't a one and only solution as fare as I know. When you are using different printers, each one will have other behaviors.

 

5 hours ago, BillieRuben said:

I just spend the last two days trying a certain tiny print with fine details (that I can't add a brim to) that keeps being shaken free from the build plate with this hatching.

Yes this is a problem. Slowing down print speed can help especially for the initial layers and bonding to the build plate. For very small parts I use often only a third of the normal print speed and increase also the number of slow layers. Changing the orientation can also help sometimes.

But you are right, this small walls should not happen at all. I mostly took attention for this behavior in the design phase and, if I can't because it isn't my design, I make the mentioned changes and/or reduce print speed drastically. This is mainly better than wasting time with multiple defect prints or hours in evaluation. Well known this isn't a perfect solution.

I mainly use two slicers, Slic3er and Cura - both known as a "not-one-click-and-happy-for-everything-solution"  🙂

 

5 hours ago, BillieRuben said:

Can any of the devs weigh in? Is there a way to switch this back to the previous slicing way? 

There are differences between all releases as burtoogle mentioned above. By the way, you didn't mentioned your Cura version as well as your printer and your adjustments in print profiles.

You can attach your .3mf file if you are not able to fix your problem. This is usually a better way to ask for help as this file includes everything including your profiles. Or try out the mentioned version of burtoogle. Or, if I remember correct, there is an other member (smartavionics?) with similar modifications.

 

I usually make a step back if I am out of ideas for an actual problem and start from scratch with clean profiles matching the used Cura version. There are too many possibilities harming a profile and never find the way back (especially if you came from an updated version). This often will work better and faster than spending days with searching and manipulating parameters.

I too went the hard way down and, as much as I like Cura, it was always a little disaster when I update an existing version and didn't setup everything from scratch.

 

@burtoogle, hopefully the cura team will implement a better wall gap filling in a future version as I find this behavior annoying too.