Computer Aided Design and Manufacture at Pineapple Sails
Computer Aided Design (CAD)
has been an integral part of Pineapple Sails since 1975, when we bought our first computer, a Vector Graphics
S-100 bus machine, with a whopping 56 k of ram. We immediately set about writing software to help design sails.
Things have certainly changed since then. The Pentium based HP Vectra XU we now use for sail design was inconceivable
20 years ago, especially as a desktop system.
The software 'front end' we use is internally developed and maintained. There is one collection of programs
which design mains, jib and asymmetric spinnakers. It is written in a derivative of basic called Mbasic,
and cross compiled into c code. There is another program for designing symmetric spinnakers, which is
written in Fortran. These programs are called 'front ends' because they write files which describe the
panel shapes of the sails which are read by a CAD program. The CAD program then allows unlimited manipulation
of the pieces after the 3 dimensional shapes have been developed. The primary operations of the CAD program
are to align the the individual pieces of a sail with the yarn direction in the sailcloth, and then the
'packing' of the pieces of the sail together for plotting and cutting by our flat
Continuous development and refinement of our design software is a never-ending process which we take
seriously. It allows us to control when the 'software upgrades' come out, rather than waiting and wondering
if the next release of someone else's software is addressing our concerns or not.
As nice as computer aided design is, computer
aided manufacturing (CAM) has so many benefits
that I'm glad we don't have choose between one or the other. They go together. The go a long way
Computer Aided Manufacturing is using computers to control machines which help in the manufacturing
process. Here at Pineapple Sails, we have a 'flat bed plotter' which is 60 feet long by 7 feet wide.
The plotter is essentially a robot which is told by a computer to go to some location on the table and
put down a pen and draw a line to some other location, or use the cutting tool and cut the cloth.
The table which supports the plotter is a vacuum table. This means that the table surface has many (5700)
holes drilled in it. These holes connect to a plenum which is connected to a large vacuum pump. After
we roll out the sail cloth on the table surface, we carefully align the cloth parallel to the edge of
the table. Then we turn on the vacuum pump, which sucks the cloth onto the table top. This
insures that the cloth holds still while the plotter/cutter moves up and down the table precisely marking
and cutting each piece of the sail.
There are many stories about Theory and Practice. You've heard the one about the two small towns separated
by a river? Well, computer aided manufacturing is like a bridge between the two towns. In this case 'theory'
is the design, and 'practice' is the completed sail.