Lui Kawasumi's Mozaika Seat

I noticed this post recently on Core 77: Lui Kawasumi: Squares and Chairs - Core77

Does anybody know how the cut edges of these metal chairs do not shred the pants of anybody that sits on them? Does the laser cutting process naturally melt and round sharp, rough edges of metal, or is there some other process the designer would have to perform in order to smooth all the edges? Thanks!

Laser cutting leaves some pretty sharp burrs and points where the molten metal sticks to the cut edge. This usually happens whenever the head stops to change direction, so typically in sharp corners and where holes start. That looks chair heavily deburred, like someone has gone over it thoroughly with an aluminum oxide pad (Scotch Brite) on a grinder. It could be waterjet cut instead of laser, which leaves a much smoother edge (since it uses abrasive flowing all over the cut).

When cut by the laser, there will be a very slight amount of slag on the backside of the sheet. I would think, and correct me if I am wrong, polishing the metal after it has been cut would remove any burrs or sharp edges.

Thanks for the replies! I learned a bit more about metal finishing.

His site says “Cut, polished, and hammered” so I’d guess there’s a serious amount of finish work getting them to smooth out. I’m guessing he had access to a laser table at RISD and not a water-jet, but I could be wrong. Very impressive forms though.

Super cool concept, but answering your question, it seems exactly like it will shred pants. It would be very hard to get into the narrow kerf to grind a bevel where the surface near planar. Possibly the whole thing could be put into a giant abrasive vibratory deburrer and have ceramic media work on the edges.