Thursday, October 28th 2004 ENGR 111 9.2 Sectioned Views

Learning Objectives List and recognize by name; symbol; and ANSI number these materials: - Cast Iron - Aluminum - Brass, Bronze, - Steel - Zinc or Copper Identify a drawing as being a: - Full Section - Offset Section - Revolved Section - Half Section - Broken-Out Section - Removed Section Given an orthographic view; draw section views: - In Pencil or - In AutoCAD Use revolutions and partial views (as conventional practices) to construct sectional views of an object. List the parts of a drawing which do not get crosshatched, even if the cutting plane passes through them. Sketch a cutting plane for any of the sections listed above

Readiness Assessment Test 9.2.1 Individually answer the following questions. You will be given 2 minutes:

Readiness Assessment Test 9.2.1 Individually answer the following questions. You will be given 2 minutes: List 4 types of sectional views.

Team Discussion Item As a team, discussing the following question: What is the purpose of sectional views?

Purpose of Sections Show internal detail Replace complex orthographic views Describe materials in an assembly Depict assembly of parts

Sectioning Practices Different parts at different angles Hatch spacing of about 1/16”-1/8” Cutting plane line .020” wide (bold) Section or hatch lines -- thin .007” Visible lines -- wide .015” Not parallel or perpendicular to boundary

Sectioning Practices When sectioning an assembly of several parts, draw section lines at varying angles to distinguish separate parts.

Most common ANSI Material Patterns ANSI No. Name Pattern ANSI 31 -- Cast Iron, General ANSI 32 -- Steel ANSI 33 -- Brass, Bronze, Copper ANSI 38 -- Magnesium, Aluminum Earth

What is ANSI? .

Available Hatch Patterns in AutoCAD

Cutting Plane CUTTING PLANE LINE The sight arrows at the end of the cutting plane are always perpendicular to the cutting plane. Line thickness of the cutting plane is the same as the visible object line. The direction of the arrow indicates the line of sight.

Types of Sections……..Fig #: Broken-out section……………6.3 Conventional breaks………….6.4 Full section……………………..6.5 Half section……………………..6.8 Revolved section……………..6.10 Removed section……………..6.11 Offset section………………....6.12 (See Essentials of Engineering Design Graphics by Vinson for figure references)

Full Section Cutting plane passes through entire object Hidden lines are omitted Visible lines “behind” the cutting plane must be shown

Individual Exercise (7 min) ● Sketch a full section of the object shown below

Individual Exercise (7 min) ● Were you correct Individual Exercise (7 min) ● Were you correct ? ● What material (hatch pattern) did you use?

Half section: A quarter of assembly removed CUTTING PLANE LINE A quarter of assembly removed Half of view is cross-hatched ALL hidden lines may be omitted Center line divides halves Center line remains only if associated feature is sectioned

Offset section: Bend the cutting plane to show more features CUTTING PLANE LINE Bend the cutting plane to show more features

Offset section: Sectional view does not denote location of offset CUTTING PLANE LINE Sectional view does not denote location of offset

Revolved section: Show cross- sections by rotating sections 90o The section view stays on the object.

Removed section: Removed sections are offset from the object.

Broken out section: Used to section a small portion of the object Does not modify the rest of the view

Conventional Practices Conventional practices are accepted drawing techniques that violate the rules of orthographic projection They are designed to simplify orthographic drawing of complex features.

Aligned Parts: Arms Lugs

Aligned Parts: Ribs & Holes Single Arm

Parts Not Sectioned. Don’t crosshatch (even though the cutting plane may pass thru them): Ribs, webs, spokes Thin parts like gaskets Ball bearings, roller bearings Most vendor items:  Bolts  Washers  Shafts  Nuts  Screws  Pins

Partial Views Use partial views to conserve space Which half depends on whether you section the view or not.

Conventional breaks: …….For extremely large parts

Crosshatching in AutoCAD AutoCAD can apply a given pattern to fill an area The area must be a closed area To fill the area use the BHATCH command.

Pair Homework Assignment Drawings (in AutoCAD): 28 all 29 all 32 a, b, c 34 all Due: Beginning of class 10.2

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