Computer Aided Design (CAD)

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Computer Aided Design(CAD)

• Engineering Drawing Standards - BS308

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Orthographic Projection
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Orthographic Projection
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Orthographic Projection
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SOME TECHNICAL TERMS (page 1)
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SOME TECHNICAL TERMS (page 1)
CAN YOU DETERMINE THE PROJECTION SYSTEM USED?
(first or third angle?) CAN YOU IDENTIFY THE
TYPES OF HOLES ABOVE?
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Projection Symbol How to Draw
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COMMON LINE TYPES (page 5)

• 1. Continuous Thick (0.5mm) TYPE A
• 2. Continuous Thin (0.25mm) TYPE B
• 3. Dashed Thin (0.25mm) TYPE E
• 4. Chain Thin (0.25mm) TYPE F

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• LINETYPES
• Hidden
• Center
• Hatch
• Outlines
• Text
• Dimension Lines
• Leader Lines

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Leader Lines

• To show where dimensions or notes apply.
• Always end in arrowheads or dots.
• Arrowheads touch and stop on a line
• Dots should be within the outline of the object.
• Long or intersecting leader lines should not be
  used.

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General Points on Drafting

• Arrows
• Triangular and Solid
• Length 3 x width
• Arrows on Dimensions -gt 3-5mm Long
• Arrows showing direction of view -gt 7-10mm Long
• Text Height Not less than 3mm.
• Underlining of text is not recommended.
• Notes of a general character to be grouped
  together.

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General Points on Drafting
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Commonly Accepted Symbols and Abbreviations

• AF
• ASSY
• CRS
• CL
• CHAM
• CH HD
• CSK
• CSK HD

• CBORE
• CYL
• DIA
• DRG
• EQUI SP
• EXT
• FIG.
• HEX

• HYD
• INSUL
• INT
• LH
• LG
• MATL
• MAX
• MIN

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Commonly Accepted Symbols and Abbreviations

• NO.
• O/D
• PATT NO.
• PCD
• RAD
• R
• REQD
• RH

• RD HD
• SCR
• SH
• SK
• SPEC
• SR
• SFACE
• SQ

• STD
• THD
• TYP
• UCUT
• VOL
• WT

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SCREW THREAD - TERMS
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SCREW THREAD - TYPES
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SCREW THREAD - External
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SCREW THREAD - Internal
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SCREW THREAD - Internal
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SECTIONS AND SECTIONAL VIEWS

• (page 12 BS308)
• Hatching is Drawn with Type B (Continuous Thin)
  Lines, equally spaced at 45º.
• Preferably not less than 4mm Apart
• With very small parts, never less than 1mm
• On adjacent parts, alternate the direction of
  Hatching.
• Correct Section Line Type F (Chain Thin)

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SECTIONS AND SECTIONAL VIEWS
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SECTIONS AND SECTIONAL VIEWS
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SECTIONS AND SECTIONAL VIEWS
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SECTIONS AND SECTIONAL VIEWS
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SECTIONS AND SECTIONAL VIEWS

• (page 15 BS308)
• PARTS NOT NORMALLY SECTIONED WHEN THE CUTTING
  PLANE PASSES LONGITUDINALLY THROUGH
• FASTNERS (bolts, nuts) SHAFTS, RIBS, WEBS,
  SPOKES of WHEELS etc.

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SECTIONS AND SECTIONAL VIEWS

• (page 15 BS308)

FASTNERS AND SHAFT NOT SECTIONED WEB NOT
SECTONED
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(No Transcript)
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OFFSET SECTIONSECTION IN MORE THAN 1 PLANE
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EXTRA RESOURCE INFORMATION

• DeGarmo, E. P., et al., Materials and Processes
  in Manufacturing, 8th Ed., Maxwell Macmillan,
  1997