Chapter 8

Section Views

TOPICS

Introduction

ObjectGRAPHICS COMMUNICATION WITH ENGINEERING DRAWINGWorking drawingOrthographicprojection(convention)Section viewsconventionSection ViewsFinishYesNo

PURPOSES OFSECTION VIEWS reducing or eliminating the hidden lines. revealing the cross sectionals shape.

EXAMPLE : Advantage of using a section view.

Terminology andcommon practices

CUTTING PLANECutting plane is a plane that imaginarily cutsthe object to reveal the internal features.

Cutting plane line is an edge view of the cutting plane.CUTTING PLANE LINEIndicate the pathof cutting plane.

ANSIstandardThick lineThick lineJIS & ISOstandardThin lineCUTTING PLANE LINESTYLESThis course

SECTION LININGSection lines or cross-hatch lines are used toindicate the surfaces that are cut by the cuttingplane.Drawn with 4H pencil.

SECTION LINES SYMBOLSCast iron,Malleable ironSteelConcreteSandWood

SECTION LINING PRACTICECOMMON MISTAKE

SECTION LINING PRACTICECOMMON MISTAKE

Kinds of Sections

KIND OF SECTIONS1. Full section2. Offset section3. Half section4. Broken-out section5. Revolved section (aligned section)6. Removed section (detailed section)

FULL SECTION VIEWThe view is made by passing the straight cutting plane completely through the part.

OFFSET SECTION VIEWThe view is made by passing the bended cutting plane completely through the part.Do not show the edge viewsof the cutting plane.

TREATMENT OF HIDDEN LINES

HALF SECTION VIEWThe view is made by passing the cutting plane halfway through an object and remove a quarter of it.

HALF SECTION VIEW

The view is made by passing the cutting plane normal to the viewing direction and removing the portion of an object in front of it.BROKEN-OUT SECTION VIEW

BROKEN-OUT SECTION VIEW

EXAMPLE : Comparison among several section techniques

REVOLVED SECTION VIEW

REVOLVED SECTION VIEWBasic concept

REVOLVED SECTION VIEWBasic concept

GivenStep 1a. Assign position of cutting plane.b. Draw axis of rotation in front view.Steps in constructionREVOLVED SECTION VIEW

Steps in constructionGivena. Transfer the depth dimension to the front view.REVOLVED SECTION VIEWStep 2

Steps in constructionGivenREVOLVED SECTION VIEWa. Draw the revolved section.Step 3b. Add section lines.

Steps in constructionGivenREVOLVED SECTION VIEWFINAL PICTURE

Placement of revolved section1. Superimposed to orthographic view.SuperimposedBreak2. Break from orthographic view.REVOLVED SECTION VIEW

6. Removed sectionREMOVED SECTION VIEW

Example : Revolved vs. removed sections.Revolved sectionRemoved sectionREMOVED SECTION VIEW

Example : Situation that removed section is preferred.REMOVED SECTION VIEWPreferredPoorToo messy !!

Example : Multiple removed section viewsREMOVED SECTION VIEWSECTION A A SECTION B B

Dimensioningin Section View

In most cases, dimensioning of the section viewsfollows the typical rules of dimensioning.GOODPOOR

GOODPOORDIMENSIONING

For a half-section view,use dimension line withonly one arrowhead thatpoints to the position insidethe sectioned portion.f 50DIMENSIONING