I wanted to build a pressfit construction kit that is using elasticity of material by a spiral lasercut.
adjusting the connector hole tikness
according to the indications in the Press-Fit_Construction_Tips, I cut a square with the laser cutter to determine the laser thikness.
I found 0.315mm
With the board of 5mm, I view that I need to draw holes of 5-0.315=4.685mm.
After I modelise a range of nicks with dimensions approching the one that's correspond to the thikness of the plywood board that i choose.
finally, 4.67mm was the good dimension.
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first draft
I then modeled a model on inkscape, using the (very handy) clone function.
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This first prototype lack of space between the turns: this causes a lack of flexibility of the part.
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Parametric model
In spite of inkscape's clone function is usefull, the parametrisation of the all part is difficult with this software.
It's why i use openSCAD, secondary to test DXF exports from this software.
I used a piece of code of Walter Hsiao on Thingiverse (a spiral generator). This code is CC-NC-BY-SA, so I'll show my code under this license.
parameters
Each piece draws constant diameter:
depending on the number of branches, the number of turns is adjusted in function of the thickness of the branches, and the gap between each branch.
So the fewer connectors, and the more the part will be flexible (because branches have a greater number of turns).
The final SCAD file is here : spiralfit.scad
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cuttings
they happened without problem.
To generate the GCODE for our lasercutter (wich is a chinese signsteak with smoothieboard opensource electronics) I use the mirific inkscape plugin (from DXF eport from openSCAD) that our member developped laserengraver_smoothie.
with parameters : Z ofset = 7mm; cutting speed = 900;
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I cut a number of connectors: 3X2, 3X3, 3X4 and 2X7.
This still gives already some design freedom
As I have chosen as parameters a thick branch corresponding to that of wood, I found other connection methods as originally planned:
Finally, it seems to be a clouds generator ...
Ce(tte) œuvre est mise à disposition selon les termes de la Licence Creative Commons Attribution - Pas d’Utilisation Commerciale 4.0 International.