John James Marshall thesis.pdf - OpenAIR @ RGU - Robert Gordon ...

7.0 Glossary
CAD/CAM is the combined acronyms of computer-aided design and computeraided
manufacturing. CAD is the use of a wide range of computer-based tools
(both software and hardware) that can be used to define 2D and 3D geometry
for use in many other applications. Computer-aided manufacturing (CAM)
refers to the use of CAD software to generate the instructions for a Computer
Numerical Control (CNC) machine tools (for example three and five axis milling
machines, multiaxis laser and water-jet cutters, tube benders, roll formers
lathes, etc.). These are subtractive fabrication methods in which some form of
computer-driven tool cuts, bends, folds, welds, rolls, forms, punches, or moulds
stock materials with much precision in two or more axes. CNC machining has
been available since the 1950s yet it is recent that the economic and
computational limitations (access to technology and ability to make use of it
without highly specialised knowledge) have come within the budget and
technical capabilities of small enterprises and individual practitioners.
Rapid prototyping and manufacturing (RP&M) consist of a number of methods
developed since the mid 1980s to fabricate physical 3D objects directly from
CAD data without the use of a mould. These methods are also known as 3D
printing, additive fabrication, solid freeform fabrication and layer
manufacturing. These are processes of micro lamination that essentially reduce
a digital 3D object to a stack of 2D profiles used to build up an object one slice at
a time from a few materials in powder, paste or liquid form. Rapid prototyping
and manufacturing techniques that are commercially available include:
Stereolithography (SLA®) 133 - is a rapid prototyping (RP) technology.
This process uses a vat of liquid photopolymer epoxy resin and an
ultraviolet laser to build parts one layer at a time. The laser traces a
cross-section of the object on the surface of the liquid resin. Exposure to
the beam solidifies the resin in the shape traced and bonds it to the layer
below.
133 http://www.3dsystems.com/products/sla/index.asp
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