ENGR 111 9.2

Sectioned Views

Thursday, October 28th 2004

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 SectionsShow internal detail Replace complex

orthographic viewsDescribe materials

in an assemblyDepict assembly of

parts

Sectioning PracticesDifferent parts at different anglesHatch 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

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

Sectioning Practices

Most common ANSI Material Patterns

ANSI 31 -- Cast Iron, General

ANSI 32 -- Steel

ANSI 33 -- Brass, Bronze, Copper

ANSI 38 -- Magnesium, Aluminum

Earth

ANSI No. Name Pattern

What is ANSI?

.

Available Hatch Patterns in AutoCAD

Cutting Plane

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.

CUTTING PLANE LINE

Types of Sections……..Fig #: Broken-out section……………6.3Conventional breaks………….6.4Full section……………………..6.5Half section……………………..6.8Revolved section……………..6.10Removed section……………..6.11Offset section………………....6.12

(See Essentials of Engineering Design Graphics by Vinson for figure references)

Full SectionCutting 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 ?● What material (hatch pattern) did you use?

A quarter of assembly removedHalf of view is cross-hatched

Half section:

ALL hidden lines may be omittedCenter line divides halvesCenter line remains only if associated feature is

sectioned

CUTTING PLANE LINE

Bend the cutting plane to show more features

Offset section: CUTTING PLANE LINE

Sectional view does not denote location of offset

Offset section: CUTTING PLANE LINE

Show cross- sections by rotating sections 90o

The section view stays on the object.

Revolved section:

Removed section:Removed sections are offset from the object.

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

Conventional PracticesConventional 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:

Single Arm Ribs & Holes

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 spaceWhich 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

Stop