2. Guiding Controls
Guiding is a Mechanical Function
performed by any component that controls
the motion of moving parts.
E.g. The mechanical function of a hinge is
guiding.
A Guiding Component or Control is a
component whose mechanical function is
to guide the motion of moving parts.
E.g. What is the guiding component for the
drawer? The wood slats.
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3. Types of Guiding
Translational Guiding ensures the straight
translational motion of a moving part.
E.g. a vertical window groove guides motion
Rotational Guiding ensures the rotational motion
of a moving part.
E.g. a bicycle wheel hub guides motion
Helical Guiding ensures the translation motion of
a moving part while it rotates about the same
axis.
E.g. threaded shank in a vice guides motion
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4. Degrees of Freedom of Movement
The Degrees of Freedom are the set of
independent movements that are possible
for a given part in a technical object.
E.g. A door can only rotate around the
hinges – 1 degree freedom
E.g. A manual transmission gear shift
moves forward/back and left/right – 2
degrees of freedom
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5. Technical Drawing: Projections
A projection is the representation of a
three-dimensional object on a two-
dimensional surface.
The most commonly used projections
are:
1. Isometric: the 3 dimensions of the object
in a single drawing.
2. Multiview: 3 views with greater detail
and no distortion: Top, Front, Side
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7. General Arrangement
A technical drawing representing the
overall appearance on an object:
multi-view or isometric
A title block gives important information;
E.g. the scale.
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8. Exploded Views
An exploded view is a drawing in which
the various parts of the object are
separated from one another;
It uses:
all the components
an isometric projection
a scale
a component list
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9. Detail Drawings
A detail drawing is a drawing specifying
all of the relevant information for
manufacturing a part.
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10. Dimensional Tolerance
An indicator of the maximum acceptable
difference between a specified
measurement and the actual
measurement on the finished object.
Part of a Detail Drawing
E.g. 50 mm 2 mm
50 mm + 2 mm = 52 mm = Maximum
50 mm – 2 mm = 48 mm = Minimum
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11. Functional Dimensioning
A drawing that specifies the information
required for the object to work.
E.g. The amount of play or space between
2 parts to allow them to move.
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12. Developments
The representation of the surface area
required to make a part by bending.
E.g. the net of a cube;
E.g. a metal sheet that will be bent.
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13. Diagrammatic Representations
A simplified representation of an object, a part of
an object, or a system to:
Show materials
Show motion
Show forces.
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15. MANUFACTURING PROCESS
Manufacturing is a series of operations
resulting in the creation of a technical
object
The manufacturing process is divided
into 3 (or 5) steps:
1. Measuring & Laying Out
1. Measuring: determining the size or position of
marking.
2. Laying Out: Tracing marks onto a material.
2. Machining
3. Assembling & Finishing
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16. Machining:
Shaping a material into a desired configuration.
Methods of Machining
Cutting: giving a material a desired shape.
Drilling: making holes in a material.
Tapping: forming screw threads inside holes
drilled into a material.
Threading: forming screw threads around a
rod.
Bending: Curving a material into a certain
shape.
Inspecting: measuring parts to specs.
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17. Assembling and Finishing
Assembling: techniques used to combine parts
of a technical object:
E.g. nailing, screwing, bonding, riveting, bolting, and
welding.
Finishing: techniques used to protect and
enhance a technical object:
E.g. painting, varnishing, staining, and polishing.
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