Polypropylene cutting using a craft cutter

When I lived in London I did a short course in furniture design at Central St. Martin’s College, run by Ben Panayi.  As part of that course I produced a design for a lampshade made from polypropylene.

I later simplified the cutting outline so that, while it looked the same when assembled, it now comprised of 4 identical shapes plus one other small shape in the centre.  In what ended up being my first ever foray into digital fabrication, I asked Medway Cutters to use their craft cutter to cut this as a trial/prototype.

Craft cutters use a drag knife, which works as the name implies: a knife is dropped into the material, then dragged along the lines specified in your CAD file.  Being a drag knife with an angled blade, it means that there will be a slight over-cut where two cutting lines meet.  Being 1mm-thick polypropylene though, these were very minimal in my lampshade.

I have kept this lampshade since then and brought it out again recently to be part of the design for a new floor lamp:

It is something I will definitely continue with for this or other pieces.