[email protected] ENGR-22_Lec-12_Section-Views-2.ppt 1 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Bruce Mayer, PE Registered Electrical

[email protected] • ENGR-22_Lec-12_Section-Views-2.ppt1

Bruce Mayer, PE Engineering 22 – Engineering Design Graphics

Bruce Mayer, PERegistered Electrical & Mechanical Engineer

[email protected]

Engineering 22

SectionSectionViews-2Views-2



Learning GoalsLearning Goals

Properly Create Section (Cut-Away) Views to Show Internal Features Of Objects That Are Not Easily Understood In Standard Orthographic Projection View Drawings



Learning Goals Learning Goals contcont

Use and/or Apply• How & Where to Construct the Cutting

Plane Line

• Section Lines (a.k.a. “Hatch Lines”)

• Several Types of Section Drawings



Section Drawing TypesSection Drawing Types

Full Section (done so far) Half Section Offset Section Broken-Out Section Revolved Section Removed Section Special Section

Conventions



Full SectionFull Section

The cutting plane passes completely through the part as a single flat plane



Half SectionHalf Section The cutting plane only passes half way through the

part The other half is drawn as usual Hidden lines are not shown on either half of the part A center line is used to separate the two halves Mostly used on cylindrical parts



Offset SectionOffset Section The multiview drawing is often difficult to interpret

when there are several hidden features on the object A sectioned view makes the object much easier to

understand An offset section allows the cutting plane to pass

through all of the significant internal features There may be several bends/kinks in the cutting plane



Offset Section contOffset Section cont The actual part would show a new visible line

(at the edge) at the bend in the cutting plane • Since the cutting plane bend is arbitrary, do not

show the line representing this bend in the sectioned drawing

Hidden lines are NOT shown

Be sure to include object lines BEHIND the cutting plane



Broken Out SectionBroken Out Section

Only a portion of the view is sectioned A jagged break line is used to divide the

sectioned and unsectioned portion of the drawing



Revolved SectionRevolved Section A cross section of the part is revolved 90° and

superimposed on the drawing A jagged break line may be used to divide the revolved

section from the rest of the drawing



Revolved Section CaveatsRevolved Section Caveats Superimposition of Rev-Sec

requires Removal of All ORIGINAL Lines Underneath the Section

Retain the TRUE-SHAPE of the Rev-Sec Regardless of the Line-Direction in the Visible-View



Removed SectionRemoved Section Similar to the revolved section

except that the sectioned drawing is not superimposed on the drawing but placed adjacent to it

The view and the cutting plane are labeled (Sec. A-A)

The removed section may be drawn at a different scale• Very Useful for Detailing Small

Parts or Features



Intersections - WindowsIntersections - Windows

a) The Offset of the intersection from the Visible Lines is SMALL or Negligible• Can DisRegard the True

Projection and Align to Vis-Lines

b) The Larger Intersection Does Have a Substantial Offset From the Visible Lines• Use the True-Projection to

position the intersection



Intersections - PortHolesIntersections - PortHoles

c) The Offset of the intersection from the Visible Lines is SMALL or Negligible• Can DisRegard the True

Projection and Align to Vis-Lines

d) Larger Intersections• For the Smaller Hole Use Tube OD

(R1) and ID (r1) Arc at Depth Found by True Projection

• For Hole K, rk = r1, SemiEllipses of Intersection appear asStraight-Lines



Special SectionsSpecial Sections There are special rules (conventions) that are followed

to make some parts more understandable Some features are rotated to their TRUE RADIAL

position in sectioned views The object is difficult to

understand using standard multiview drawings where hidden lines are used to represent internal features



Special Sections contSpecial Sections cont Many Times If a part is sectioned as it would actually

appear if cut, the details of Features such as ribs and holes may not be clear

Since the goal is to make the drawing easy to interpret the drawing is modified by the following std conventions• The cutting plane shows that the features are revolved to their

true radial position• Hidden features are not shown• The sectioned drawing

produced is a DISTORTED, but CLEARER, picture of the object

• The section drawing appears as a full section

• The arrows show the directionof the view



Special Sections contSpecial Sections cont Ribs/Webs are not

sectioned when the cutting plane passes through them lengthwise

Ribs are sectioned if the cutting plane passes through them at other orientations



SpecialSpecialSectionsSectionscontcont

The side view is replaced by a full section view The cutting plane shown in the Front view shows the

direction of the line of sight The holes and ribs have been revolved to their true

radial position The ribs are not sectioned in this orientation The section lines are all drawn at the same angle

since the object is one solid part



Conventional Breaks

Use Conventional Breaks to Shorten an Elongated Object

“Jagged” Lines are used to Break Non-Circular Cross-section Objects

“S” Breaks are Preferred for Cylindrical Objects



Demo – Pipe IntersectionDemo – Pipe Intersection

Let’s make a Cross Section for a Drilled, Thick-Walled Pipe



Final ResultFinal Result



All Done for TodayAll Done for Today

Blue PrintCrossSec

Circa 1862



Bruce Mayer, PELicensed Electrical & Mechanical Engineer

[email protected]

Engr/Math/Physics 25

AppendiAppendixx

6972 23 xxxxf



Intersect Demo Intersect Demo



Intersect Demo Intersect Demo cont cont



Hatch Procedure-1Hatch Procedure-1




Hatch DiaLog Box

4




Pick Hatch Areas by Clicking ONCE ANYwhere within the Region







All Done

Documents

[email protected] ENGR-22_Lec-12_Section-Views-2.ppt 1 Bruce Mayer, PE Engineering 22 – Engineering Design Graphics Bruce Mayer, PE Registered Electrical