This week I played with AutoCAD and CorelDRAW to design a press fit
corrugated cardboard model of a skid steer.
I originally designed a 3D scale model of a skid steer using
Pro/E. The drawing turned out relatively well, but extracting
data from the 3D model to create 2D planes was challenging, so I
started over using AutoCAD.
The first thing sketched up was some small pattern strips to test
the fitment. The general pattern I started with was drawn to
be an exact fit. After cutting two small pieces, the fit was
too loose. I measured the pieces and determined that the laser
cuts 'online' versus 'outside' the line, which meant my 'exact fit'
would be 0.003" small. I adjusted my pattern to be 0.004"
larger/smaller (depending if the geometry would be male/female).
The result of the first cut of all the pieces:
The picture shows the pieces needed for the assembled model with the
waste material removed.
I assembled the parts with ease, the press fit design worked
well. I did not have any chamfered corners as I wanted the
model to visually be solid.
The model isn't complete per se, but the concept is there. I
have holes in the sides that hold the loader arms in place and allow
them to rotate. I was trying to determine a way to add tires
that would roll with the model, but ran out of time before a good
solution was found.
Problems:
Not everything works as planned the first time through. I made
one small design flaw on the bottom (floor) piece, which you can
spot in the picture of the pieces sitting in the machine. I
forgot to include holes for the 'inner side' pieces to press into
(in the picture, the two pieces on the far left side needed to have
similar cutouts in the interior). So I added the rectangles
and cut a new one.
