Option C: CAD/CAM
C2 – CAM SYSTEMS
Additive manufacturing techniques.
 The manufacture of 3D parts by depositing molten
material in a series of layers.
Subtractive manufacturing techniques
(wasting).
 The manufacture of 3D parts by removing (cutting)
unwanted material from a block.
Compare subtractive and additive
manufacturing techniques.
 Subtractive
manufacturing
techniques remove
material (waste) to
manufacture parts.
 Additive products have
minimal wastage and the
end product is built from
a number of parts or a
continuous extrusion of
material.
Describe a Laser Cutter.
 A device that is able to laser cut and engrave 2D
shapes.
Describe Rapid Prototyping (RP).
 A device that is able to produce a complete product
including internal details.
Describe a Plotter Cutter.
 A device that is used to cut 2D shapes from card and
vinyl.
Explain how CNC routers, milling machines,
laser cutters and plotter cutter machines can be
used to manufacture a variety of outcomes
(subtractive).
 Consider a range of products that have been made
using subtractive CNC equipment, for example,
signs, vacuum form moulds, flat-pack furniture.
Explain how RP (rapid prototyping)
machines can be used to manufacture a variety of
outcomes (additive).
 Consider how rapid prototyping has been used to
reduce development time and how one-off
products are made for different situations.
Explain a situation in which it would be
advantageous to use subtractive or additive
manufacturing when making a product.
 Use product examples to illustrate the advantages
of both processes.
Explain how a variety of tools can be used to
make a complex outcome.
 Multi-tool CNC machines are used where the
outcome requires more than one cutting process.

For example, a CNC lathe is able to drill, ream, cut and partoff.
Discuss the advantages and disadvantages of using
large or small-diameter tools when machining.
 Large-diameter tools cut
a larger area, thus
reducing the amount of
time needed to complete
a task.

However, large-diameter
tools leave large radiuses
in internal corners.
 Small-diameter tools
have to use a higher
spindle speed, and feed
rate is normally slower,
but they are able to
perform more intricate
jobs.
Define Machine Tool Step Variable.
 This applies to 3D profiling.
 It is the amount of tool that passes over work already
cut and determines the quality of the finished
surface.
 It is expressed as a percentage—the higher the
quality, the higher the percentage.
Outline how the machine tool step over variables
can determine the output quality of a product.
 When using a ball nose cutter for 3D profiling, the
tool step over should be reduced to give a better
quality finish.
Raster, spiral and pocket cutting to manufacture.
 Raster cutting is where the tool path cuts in straight
X,Y paths.
 Spiral cutting is where the tool path is circular,
which is especially useful for round and curved
objects.
 Pocket cutting is where the tool path is determined
by individual Z coordinates across the product.
Discuss how machining paths alter the
quality of a product and amount of time
required in order to produce it
(consider raster, spiral and pocket
machining).
 Use post-processing software to simulate the
amount of time needed to cut a product using
raster, spiral and pocket machining techniques.
Limitations of using three-axis machining when
making a 3D product.
 Consider undercuts and a flat base.
G code.
 Coordination-based code that also includes feed
speed and stop/start
Outline how a 3D CAD drawing is converted into
a CNC file using G codes.
 3D CAD drawings are converted to G code using
post-processor software such as GeoCam.
 Drawings are exported as an STL file, which
triangulates the design, allowing the software to
determine the path of X,Y,Z coordinates.
Feed Speed.
 The feed speed is the rate at which the cutting tool
moves in X, Y and Z paths
How feed speeds change depending on
material and size of tool.
 Metals are cut at a slower feed rate than that of wood
due to the hardness of the material.
 A larger diameter tool will waste more material, thus
causing its feed speed to be reduced.
 Spindle speed is also altered to suit material and tool
diameter.
How limitations of tooling can affect the manner
in which an object can be designed and
manufactured.
 The limitations of tool length and diameter affect
the final design and manufacture of a product.
 Internal corners will all have radius and deep
pockets will not be able to be cut by small diameter
tools.