Thin walls with different thicknesses

Hello everybody,

I think there had been already some posts about thin walls, but I have not found any with my issue:

What is your approach, when you have to print several thin walls with different thickness?

My results so far:
Either Slic3r is doing a single wall or a double wall.
I made a test-object (see attachements) with different wall thicknesses from 0.4mm to 1.2mm

The results were: (manually measured with calipers, so a +/- 0.1mm might be there)
Model Result
0.4mm 0.7mm (single wall)
0.5mm 0.6mm (single wall)
0.6mm 0.6mm (single wall)
0.7mm 0.6mm (single wall)
0.8mm 0.6mm (single wall)
0.9mm 1.1mm (double wall)
1.0mm 1.1mm (double wall)
1.1mm 1.1mm (double wall)
1.2mm 1.3mm (triple wall)

I of course understand that the Slic3r has to decide if the wall is either a single or double wall,
BUT
do you know of any tricks how to come near to the model? (e.g. making a "thick" single wall?)

As I often have models with many different thicknesses I cannot "optimize" my slicing parameters for a particular thickness (e.g. 0.7mm).

Thank you for any hints for optimsation!
Leo

Edited 1 time(s). Last edit at 01/07/2015 03:55PM by KORYBA.

If the wall thickness is less than twice the extrusion thickness it will print a single wall. If it is exactly twice the extrusion thickness you will get a filled double wall, but if it is above twice the thickness and less than 3 times the thickness you will get a hollow wall. At 3 times the thickness or above the wall will be filled if you have single perimeters set. With a fixed extrusion width it's down to simple geometry - you cannot print a 0.9mm wall if the extrusion thickness is 0.5mm for example, because a single wall is 0.5mm and a double wall would be 1mm thick.

If you have a need for a particular thickness of thin wall, then set the extrusion width manually so that the wall is an exact multiple of the extrusion thickness (but it won't print well if you set the thickness to be a lot different to your nozzle diameter).

Dave

What happens if a wall is printed with a 0.4mm nozzle, but enough plastic is extruded for a 0.5mm wall? Won't the wall come out to be about 0.5mm?

Dave: KORYBA has already said that he has objects with many different sized thin walls, So changing a setting might make one wall come out right, but others will be wrong.

Quote
rew
What happens if a wall is printed with a 0.4mm nozzle, but enough plastic is extruded for a 0.5mm wall? Won't the wall come out to be about 0.5mm?

Dave: KORYBA has already said that he has objects with many different sized thin walls, So changing a setting might make one wall come out right, but others will be wrong.

Yes, the slicing software could indeed vary the extrusion width to best suit the thickness of each thin wall, but as far as I know Simplify3D (from version 2.2.0) is the only slicing software that (I think) currently attempts this (in "Advanced" section "Thin wall behaviour" tick "Allow gap fill when necessary"). AFAIAA Slic3r uses a fixed extrusion thickness for perimeters (and a different fixed width for infill), and so will not fill thin walls that are not an exact multiple of that width. It has nothing to do with nozzle size, only extrusion width, though the default extrusion width is based on nozzle size (but can be over-ridden), and you will not get a satisfactory print if the extrusion width differs from the nozzle diameter by too great an amount.

Dave

Hi everybody,

Thank you for your answers so far: Summing up I understand the following:
In theory it would be possible to slice (and print) thin walls with different thicknesses by calculating a variable extrusion width.
I assume that variable extrusion width will also have an impact printing quality.

However, in practice this is currently not possible in Slic3r!

Leo

Quote
KORYBA
Hi everybody,

Thank you for your answers so far: Summing up I understand the following:
In theory it would be possible to slice (and print) thin walls with different thicknesses by calculating a variable extrusion width.
I assume that variable extrusion width will also have an impact printing quality.

However, in practice this is currently not possible in Slic3r!

Leo

Yes, I believe that is all correct - though extrusion thickness should be able to be varied sufficiently for any thin wall without significant impact on quality. Absolute worst case would need a variation of +/-33% of the optimal thickness (assuming the wall is no thinner than 66% of optimal).

Dave