Week 7: Make something big !

This assignement was conducted 4-6 july. I had no access to a ShopBot before (there is no ShopBot at Digiscope. We had access one day to another FabLab, but it was to short for the 5 students...). Our own ShopBot was installed the 1st july in FabLab Sorbonne Universités. All the work was conducted at FabLab Sorbonne Universitées.

Object: high stool

Design

From my point of view, one of the challenges with press-fit designs is to take into account the sheets thickness. Parametric design is absolutely needed. I was unfamiliar with Solid Works, Fusion 360 or any similar CAD tool. My only previous knowledge was about OpenSCAD. I decided to work with Fusion 360. I learned how to use basic functions in two hours with one of the student working at FabLab Sorbonne Universités, Royce Florian. I then found that very good tutorial by Gerit Coetzee about parameters in Fusion 360

Here is an example withe the seat of my stool, with thickness parametrized:

The final design uses many parameters: the global size (proportionnal to radius of plateaux and to height), the thickness, and the offset (to adjust press-fit). The final values used are 600mm for the height, 10mm for the thickness, 0.1mm for the offset.

Here are the DXF files, for the seat, for the supports, for the bottom.

Fabrication

The first attemps is a disaster: the trace hits the limit of the workspace:

I took advantage of this failure to test my press-fit parameters:

After one day of attempts and errors, I managed to place several traces on the same workspace, within the same file:

In VCarve, it is easy to draw a line to cut the pieces from the wood that can be stored for later use:

Result

Assembly is effortless (no need for a hammer), and the result hangs well (no need for glue or nails):

It appeared that the design is richer than expected: the stool can be used either as a stool, or as a small table:

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