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Sectional Views (Pandangan Potongan)

Nazrul Effendy, ST MT. PhD.Department of Engineering Physics

Nazrul Effendy, UGM 1

Department of Engineering PhysicsFaculty of Engineering, Gadjah Mada University

Gambar Teknik ?

• Bekerja di Industri• Menjadi

Peneliti/Dosen• Studi Lanjut• Menjadi Pengusaha

MendukungSkill

Untuk:

Gambar Teknik - Pengantar 2

Gambar Teknik - Pengantar 3 Gambar Teknik - Pengantar 4

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Gambar Teknik - Pengantar 5 Gambar Teknik - Pengantar 6

ContohPembuatan Mur dan Baut

Nazrul Effendy, UGM 7

Learning Pyramid Lecture

Reading

Daya Ingat Rata-rata5 %

10 %

Audio Visual

Demonstration

Discussion Group

20 %

30 %

50 %

Practice by Doing

Teach Others / Immediate Use

70 %

90 %

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PROJECTION METHOD

PROJECTION METHOD

Perspective

Oblique Orthographic

Parallel

Axonometric Multiview

PROJECTION THEORY

The projection theory is used to graphically represent

The projection theory is based on two variables:1) Line of sight

) l f ( l l )

3-D objects on 2-D media (paper, computer screen).

2) Plane of projection (image plane or picture plane)

Line of sight is an imaginary ray of light between an

observer’s eye and an object.

There are 2 types of LOS :parallel convergeand

Line of sight

Parallel projection

Line of sight

Perspective projection

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Sejarah proyeksi orthogonal• Abad ke-18: Gaspard Monge (1746-1818)

ikut terlibat pada perancangan gudangsenjata Dia mengembangkan suatu sistemsenjata. Dia mengembangkan suatu sistemmenggunakan 2 bdg proyeksi yg salingtegak lurus utk mendeskripsikan bendapadat proyeksi orthogonal

Nazrul Effendy, UGM 13

Orthographic View

Nazrul Effendy, UGM 14

Orthographic Projection

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Contents

S i Vi • Section Views • Third Angle Projection• Two View Drawings• Auxiliary Views

Sections Views, Nazrul Effendy, UGM 16

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Cutting Plane• The sight arrows at

the end of the cutting

CUTTING PLANE LINE

gplane 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.

Section Views• Section views are used to clarify

internal detail and to avoid dimensioning to hidden lines

• They are established by f l

A A

referencing a cutting plane• Cutting planes depict the exact

location on the part from which the section view will be projected, and should have associated arrowheads, indicating the direction from which the section view will be observed view will be observed.

• Cutting planes are constructed as an integral feature of the parent view, and cutting plane arrowheads always indicate the direction for the observer’s line of sight.

SECTION A - A

0.7mm0.35mm

• the hatching lines are equally spaced and • the hatching lines are equally spaced and drawn at an angle of 45° to the principal centre line in each example. jkmaterialnya adalah steel

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Purpose of Sections• Show internal detail • Replace complex • Replace complex

orthographic views• Describe materials

in an assembly• Depict assembly of Depict assembly of

parts

Sectioning Practices

• Different parts at different anglesp g• Hatch spacing of about 1/16”-1/8”

(1.59-3.18 mm)• Cutting plane line .020” ( = 1 mm)

wide (bold)• Section or hatch lines -- thin 007” Section or hatch lines thin .007

(0.18 mm) • Visible lines -- wide .015” (0.38 mm)• Not parallel or perpendicular to

boundary

• When sectioning an assembly of

Sectioning Practices

assembly of several parts, draw section lines at varying angles to distinguish

t tseparate parts. • A bush is shown in the above Fig. in a housing. • There are two adjacent parts and each is cross

hatched in opposite directions. • It is customary to reduce the pitch between

hatching lines for the smaller part.

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Most common ANSI Material Patterns

• ANSI 31 -- Cast Iron GeneralANSI No. Name Pattern ANSI 31 Cast Iron, General

• ANSI 32 -- Steel

• ANSI 33 -- Brass, Bronze,Copper

ANSI 38 M i • ANSI 38 -- Magnesium, Aluminum

• Earth

What is ANSI?

.

Available Hatch Patterns in AutoCADTypes of Sections• Full section• Half section• Offset section• Revolved section• Removed section• Broken-out section

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•in Plan (A), the sectional plan gives clearly the exact outline along the horizontal axis where the casting has

d t h b tassumed to have been cut.• This contrasts with the confusion in Plan (B) which obviously results from attempting to include all the detail by insertingthe appropriate dotted lines.

Wh th l ti f i l • Where the location of a single cutting plane is obvious, no indication of its position or identification is required.

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?

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• A quarter of assembly removed• Half of view is cross-hatched

Half section: CUTTING PLANE LINE

ALL hidden lines may be omittedCenter line divides halves

Center line remains only if associated feature is sectioned

Half Sections

• Symmetrical parts may be drawn half in section and half in outside view.

Pandangan potonganDapat dibuat denganbukan aris lurusbukan garis lurus

• Bend the cutting plane to show more features

Offset section: CUTTING PLANE LINE

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• Sectional view does not denote location of offset

Offset section: CUTTING PLANE LINE

of offset

Pandangan potongandapat dibuat denganbukan garis lurusbukan garis lurus

Removed section:

SECT D-D SECT E-E R.05

Removed sections are offset from the object.

E F

.82

.2 (4).92

SECT F-FE F

Potongan sebagian

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A

Projected Section Views

A SECTION A – ASECTION A AROTATED 30º CLOCKWISE

• Show cross- sections by rotating sections 90o

The section view stays on the object.

Revolved section:

Without breaks

With breaks

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

Third Angle Projection

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Multiview Projection –Proper number of Views

• It may not, be necessary to show all six views to completely describe the objectcompletely describe the object.

• In fact, the minimum number of views is preferable.

• How many views are necessary to completely describe this plate?

• 1?• 2?• 3?• 4?

Multiview Projection – Two View Drawings

• The answer is 2!

Sectional Views• We have covered the basic method of representing an object by

projecting views. This allows us to see the external features of an object.

• Often times it is necessary to view the internal features, this is Often times it is necessary to view the internal features, this is accomplished by slicing through the object and producing a sectional or section view

Section view is always placed BEHIND arrows

Object being sectioned

Section LineAlways a phantomLine type

View ArrowWith Label

Sectional Views• Sectional views are extremely useful in minimizing the number

ofprojected views. How many views does this object require?

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Sectional Views• Section views provide clear and unambiguous

representation of internal features

Sectional Views• Sectional views can reduced the number of views of

many axisymmetric parts to a single view

Auxiliary Views• Inclined planes and oblique (neither parallel nor perpendicular)lines

appear foreshortened when projected to the principle planes of projection.

• To obtain a true size view, auxiliary views are created using similar techniques as for creating standard views, unfolding about an

iaxis…