Boat Parts Prepared for NC Cutting
Kasten Marine Design, Inc.
Copyright 1999 - 2003 Michael Kasten
What is NC...? It simply means Numerically
Controlled...!
The role of the Maxsurf companion
program, Workshop, is to create structure. From Workshop one can
output parts via DXF, and then add detail within a dedicated CAD program
such as Microstation or AutoCAD. In the CAD environment, parts are also
nested to fit the plates where the parts will be cut. Here's a link to a
general discussion of
NC Boat Building Advantages.
For a concise outline of the NC file generation process, see the article
describing our Our CAD Design Stream.
In the above image from Microstation, we see some parts for the small
aluminum Tug-Yacht, Boojum, ready for nesting.
The Nested Parts image is one of the cut files, ready
to be sent as an email attachment to Mico-Wakefield in Auckland, New Zealand
for plasma cutting.
The Cut Plate image is the same nesting,
having been cut and shipped to the builder, Q-West in Wanganui, New
Zealand. The parts were left "tabbed" to the plate for ease of handling. The
pre-cut pieces at this point are ready to be separated and assembled in
order to create the vessel's frames.
The Framing Erected image shows those same parts
assembled into the frame of the boat, and stringers are being bent in. The
images in the second series of links show images of the vessel nearing
completion.
The original cut-files, as in the image shown above, are plotted to a
smaller scale and become the guide to assembly of the cut parts.
A pre-cut "boat kit" has the potential to save the builder quite a lot of
labor, not only for the cutting itself, but for the lofting and layout of
the parts. With a one off project, NC cutting may save as much as 30 to 50
percent or more of the hull fabrication labor on a metal boat, the
differences being due to varying builder techniques, and to varying amounts
of NC detailing being provided.
Done well and with attention to detail, this
approach pays off handsomely in terms of the cost of developing the NC files
versus the amount saved during construction of the hull. In other
words, for a metal boat the cost of developing the cut files can usually be earned back
several times over.
With a GRP vessel, this approach yields substantial labor savings
for mold construction. NC cutting can be used for mould making by simply
detailing the structure on the 'outside' of the hull surface.
Mould frames complete with notches for stringers, etc. can be cut by a
computer driven router. Even the mould sheathing can be NC cut if
desired.
It is equally possible to have a male or female
mold carved by a five-axis NC router directly from the computer model. In terms of
labor, this is extremely efficient and cost effective, there being very
little manual labor involved in creating the tooling prior to the layup of
the GRP part.
Computer Modeling & Analysis Links
