String Art Triple-Layer Star

A rather spectacular string-art star that may require some patience to get your settings dialled in, but is a pretty amazing print to behold when you are in The Zone. To help you get in The Zone I have included a single-layer single-sector test part that prints in around 6 minutes for you to experiment with.

Printing it you need to move fast and pump hard! 

Be wary of my gcode - it may be a bit too fast if you have a stock nozzle. I have uploaded the project files for you to try your own settings with - the settings below work well for me. Save your settings as For String Art - you won't want them updating your default settings.

0.3mm layer height - 0.4mm nozzle.

Filament Settings

PLA - 215+

Extrusion multiplier x1.4 - important (you can tune around this value, but know that it needs ramping up a lot from default)

Cooling - Cooling Thresholds - set “slow down if print layer is below…” to 2s - you don't want it deciding to slow down when you are trying to bridge strings.

Layers & Perimeters settings 

Use Arachne perimeter generator, and tick all the quality boxes apart from Detect Thin Walls. If you have not upgraded to PrusaSlicer 2.5 then you don’t have Arachne, and then you should tick Detect Thin Walls.

2 solid top and bottom layers. I like Archimedean Chords on both.

Infill 0% - in order to ensure that The Real Secret (below) is implemented without disruption. May not be appropriate for other string art models.

Speed

I used perimeters 60 and bridges 96mm/s. However I have a CHT nozzle which allows me to run at 1.6x default profile speeds (it is an awesome upgrade - get one! Yes brass nozzles cost 1/20th the price but it is peanuts for the time you will save).

I didn’t bother with a brim and did get a little bit of curling up at the ends of the arms, but nothing to worry about.

Colour Changes

These are at layer 33 and 65. You don’t have to change colour but why wouldn’t you?

The Real Secret

Finding settings that enable you to bridge large distances is one of two secrets. The other, more arcane secret is optimizing the geometry of the model itself, which has been tweaked to encourage the slicer to draw the all the strings in a layer in one continuous unbroken path, a bit like vase mode. This is the purpose of the tiny tunnels through the ribs, through which the strings run, and while they are not really perceptible in the physical print, they are enough to bend the gcode to do my bidding, at least in the mid-layers of the string stack where it had been failing. N.B. the star cannot be printed in vase mode. An early version of the test part, prior to adding the tunnels, printed very well in vase mode. I have not tried to print the test part subsequently but would guess that the tunnels might prevent vase mode from working. But that isn't what the part is there to test so doesn't matter.

It took some R&D to find the settings, and gain and act on this modelling insight, but as you can see from the photos, I arrived at a combination that worked for me, and hopefully will for you too, or at least point you in the right direction.

Giving it as a gift? It fits nicely in the cardboard box that a 1kg filament reel comes in.

Please upload pictures of your successful makes and comment whether the settings worked or how you changed them if they didn’t.