Option C: CAD/CAM
C3 – THE IMPACT OF CAD/CAM ON
MANUFACTURING
Numerical Control
 Automated machines that require data to be inputted
manually by a trained operator
Explain how a numerically controlled
(NC) machine aids manufacturing.
 An NC machine is able to reproduce manufactured
parts in large quantities
 NC machines can be used reliably in situations
requiring continuous operation in areas that would
normally expose operators to hazardous conditions.
Computer Numerical Control (CNC).
 Refers specifically to the
 Each code is assigned to
computer control of
machines for the purpose
of manufacturing
complex parts in metals
and other materials.
 Machines are controlled
by a program commonly
called a “G code”.
a particular operation or
process.
 The codes control X,Y,Z
movements and feed
speeds.
Compare numerical control and
computer numerical control.
 Numerical control
machines are not
connected to a computer.

An operator inputs the
data manually.
 A CNC machine accepts
and operates from
computer data.
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A CNC machine offers
great flexibility over that
of NC.
Products are made
accurately.
CNC machines are
economical to operate, but
initial costs are high.
Explain how a CNC machine further
aids manufacture.
 Global communication
systems allow for the
CNC machining data to
be sent anywhere in the
world.
 The flexibility of a CNC
machine reduces downtime between batch runs
or one-off production.
 CNC machines can be
incorporated into a CIM
(computer integrated
manufacturing)
environment to control
individual requirements
and consumer needs.
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Greater flexibility
Reprogrammability
Multi-machine control
Tooling
Multi-axis machining
Describe two- and three-axis
machining processes.
 Two-axis CNC lathe:
workpiece motion (rotary
axis)

X,Y axes for cutting.
 Three-axis machining
for milling, routing and
engraving:

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Z axis for depth of cut
X and Y axes for direction
of cut.
Describe four- and five-axis
machining processes.
 Four-axis machining is a
 Five-axis machining is a
lathe with a milling head
attachment; X,Y,Z axes
plus an additional
rotary motion.
milling machine with
three linear axes (X,Y,Z)
with rotation about two
axes.
Milling machines and routers can be interfaced in
a CAD/CAM system.
Issues faced by the designer and manufacturer
when choosing CNC equipment.
 Costs
 Flexibility
 Maintenance
 Tooling
 Training,
 Speed and quality of finish.
Outline how a CNC lathe is interfaced in a
CAD/CAM system to produce a 3D model.
 Consider a suitable product to be made on a lathe
and outline the advantages and disadvantages to
the operator.
Computer Integrated Manufacture (CIM).
 A system of manufacturing that uses computers to
integrate the processing of production, business and
manufacturing in order to create more efficient
production lines.
Describe how CAD/CAM can be
integrated into a CIM system.
One example of a CIM system.
 For example, car production.
 Vehicle ordered to customer specification.
 Materials and third-party parts ordered to allow JIT (just-intime) manufacture.
 Assembly checked for quality throughout, allowing for
minimal wastage.
Discuss the advantages and disadvantages of
CIM to consumers and manufacturers.
 Manufacturer:

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Initial set-up costs
Staff morale
Storage and reduction of
waste.
 Customer
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Cost-effective product
Quality
Individual needs.