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February 2nd 2002 Page 2
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...after a surprisingly short time the smiling courier
delivers half a dozen packs of laser cut 3mm plywood models. At
this stage the pieces are held in place by masking tape. Once the
prototyping stage is complete small tags will be added by turning
the laser off at appropriate moments.
So; to work, to see if the parts actually fit together.
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Before I write about assembling the parts, allow
me to digress... I am already familiar with die cutting from our
cardboard models such as Skiing Sheep which is already cut that
way. Die cutting involves the creation of a die and the setting
up of die cutting machinery. The initial costs are very high, small
runs, such as are involved in prototyping are expensive and changes
are expensive to make. The advantage, though, is the economy of
scale. Order large quantities from the die cutter and the prices
tumble. Quite apart from the unsuitability of die cutting as a prototyping
tool, I still need to overcome the problem that, at present, I can't
find a company that will die cut plywood for me!
Laser cutting, on the other hand, has a very low set up cost. The
file is put into the computer, the wood onto the cutting bed and
away it goes. This means that for short production runs, or for
prototyping, laser cutting is very cost effective. Unfortunately,
there are few economies of scale: order 100 kits and the price per
kit will be similar to the price for 10000 kits.
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Back to the model. The photograph here shows the
first assembled Late Bird using the laser cut pieces. Looks good
doesn't it! And it feels nice; Solid, with that slightly rough texture
of finished ply and a woody aroma!
The pieces fitted together okay although they weren't
the tight fit I had hoped for. The biggest problem was the gears.
They just didn't turn properly. They were actually too widely spaced
to move freely. If you study the picture you can see that the teeth
of the small gear don't mesh fully with the larger gear.
(1) (2)
(3)
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