Graphics Reference
In-Depth Information
Designing machine parts: Solid modeling CAD
Solid modeling software was born from industrial design and manufactur-
ing. Solid modeling design packages are eficient and offer a user a built-in,
ready-made library of core shapes and standard machine part geometries that
can be quickly customized and combined. For example, two cylinders could be
combined together to make a mallet, and a third cylinder could be subtracted
to create a hole for hanging it on the wall. Because solid modeling software
represents shape as a collection of volumes, most 3D printers today can “speak”
to these types of design iles luently.
Solid modeling design software has years of manufacturing and design
experience built into it, and it shows. The software “speaks” in an old-school
machine-shop vocabulary using words such as extrude, drill, and chamfer.
It shows design operations in recognizable realistic form, for example, as a
drilled hole, a milled notch, or a rounded-off edge.
Solid modeling software took off in the 1990s when computing power
increased to the point where the design software could “remember” iterations
of previous designs and allow users to skip back and forth between them, undo
changes, and retrospectively change dimensions. We take it for granted now
that our computer will remember each version of a document, spreadsheet or
design ile, but it wasn't always so convenient. When design software inally
gained this capability, it took the CAD world by storm. Parametic modeling
enabled designers to keep editing and experimenting with their design—no
pencil, erasers, and torn-through sheets of paper needed.
Design software has streamlined worklow, improved communications
and enabled companies to store design knowledge. Before design software
became a critical part of the manufacturing process, designers, engineers,
and manufacturers worked in loosely connected but separate organizational
compartments. These days, a solid modeling tool can tell its users whether
a proposed design for a new gadget will come out right when forced into an
injection molding machine using a particular type of green plastic. Design
software can help designers cut down the number of separate parts to save on
manufacturing and assembly costs.
Today's commercial CAD packages can be knit into a company's supply
chain. If engineers want to change the size or material composition of a key
engine widget, they can check the change against the company's inventory to
compare the new version against existing widgets. If a new widget is added to
