Menggambar Teknik - Potongan

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Materi menggambar teknik mengenai potongan

Transcript of Menggambar Teknik - Potongan

  • 22/10/2014

    1

    POTONGAN

    Menggambar Teknik TL

    Sistematika

    1. Membaca proyeksi ortogonal

    2. Potongan

    3. Materi Terkait Tugas

    a. Skala

    b. Tugas 3

    MEMBACA PROYEKSI ORTOGONAL

    Reading a drawing is the process of recognizing the shape of an object by interpreting the orthographic views.

    DEFINITION

    Orthographic Writing

    Orthographic Reading

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    F.V. R.S.V

    T.V.

    L.S.V

    B.V.

    VIEWING DIRECTION

    Given

    Analysis by Solids

    ORTHOGRAPHIC READING

    Objects are decomposed into solid geometric

    primitives.

    BASIC IDEA

    Rectangular prism

    Cylinder

    Negative cylinder (Hole)

    Some of familiar solid objects

    Objects are decomposed into solid geometric

    primitives.

    BASIC IDEA

    Cone

    Pyramid

    Sphere

    Some of familiar solid objects

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    READING STEPS

    1. Orient yourself with the views given.

    (Choose the viewing direction.)

    2. Read the individual surfaces that appeared in

    each view and related to each other.

    3. Create a proper solid geometric primitive from

    each reading.

    4. Assembly all of solid geometric primitive

    according to orthographic views.

    EXAMPLE A

    Given

    Front View

    Rectangular prism

    Hole

    Composition

    Given

    Rectangular prism

    Composition

    Front View

    Cylinder

    EXAMPLE B

    Given

    Cylinder with a blind hole.

    Composition

    L-shaped with round end

    Hole

    EXAMPLE C

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    Composition

    Wedge Given

    EXAMPLE D Composition

    Given

    EXAMPLE D

    L-shaped block

    Wedge

    Analysis by Surfaces

    ORTHOGRAPHIC READING

    2. Read the individual set of lines or surface that

    appeared in each view and related to each

    other.

    1. Orient yourself with the views given.

    An understanding in orthographic projection, i.e.

    meaning of lines and surfaces are almost

    important.

    READING STEPS

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    4. Repeat steps 2 and 3 until all surfaces are read.

    During this repeating process, the details of

    an object are added up until its completed

    shape is obtained.

    3. Mentally create and sketch a form of the surface

    that produce the same orthographic views as

    those at the beginning.

    READING STEPS GUIDANCE 1

    Adjacent areas that are not in the same plane must be

    separated by lines.

    Different plane

    Line exists

    Edge view

    Same plane

    Edge view

    Top view

    A

    B

    C

    EXAMPLE

    All surfaces A, B and

    C are not in the same

    plane.

    Some of possible objects shape.

    A

    B C

    A

    B C

    A

    C

    B

    GUIDANCE 2

    Areas that show a similar shape in more than one

    view is the same surface.

    Similar shape

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    GUIDANCE 2

    Areas that show a similar shape in more than one

    view is the same surface.

    POTONGAN

    Object

    GRAPHICS COMMUNICATION

    WITH ENGINEERING DRAWING

    Working

    drawing

    Clear ?

    Orthographic

    projection

    (convention)

    Section views

    convention

    Section Views

    Orthographic

    Projection

    Finish

    Yes

    No

    Dimensioning

    PURPOSES OF SECTION VIEWS

    Clarify the views by

    Facilitate the dimensioning.

    reducing or eliminating the hidden lines.

    revealing the cross sectionals shape.

    Let See the example

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    EXAMPLE : Advantage of using a section view.

    ISTILAH DALAM POTONGAN

    Cutting plane

    CUTTING PLANE

    Cutting plane line

    Cutting plane is a plane that imaginarily cuts

    the object to reveal the internal features.

    Section lines

    Cutting plane line is an edge view of the cutting plane.

    CUTTING PLANE LINE

    Indicate the path

    of cutting plane.

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    ANSI

    standard

    Thick line

    Thick line

    TS & ISO

    standard

    Thin line

    CUTTING PLANE LINESTYLES

    Viewing direction

    Viewing direction

    Viewing direction

    This course

    SECTION LINING

    Section lines or cross-hatch lines are used to

    indicate the surfaces that are cut by the cutting

    plane.

    Section lines

    Drawn with thin lines.

    SECTION LINES SYMBOLS

    The section lines are different for each of

    materials type.

    Cast iron, Malleable iron

    Steel Concrete Sand Wood

    For practical purpose, the cast iron symbol is

    used most often for any materials.

    SECTION LINING PRACTICE

    The spaces between lines may vary from 1.5 mm

    for small sections to 3 mm for large sections.

    COMMON MISTAKE

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    SECTION LINING PRACTICE

    It should not be drawn parallel or perpendicular

    to contour of the view.

    COMMON MISTAKE

    TREATMENT OF HIDDEN LINES

    Hidden lines are normally omitted from section

    views.

    TIPE-TIPE POTONGAN

    KIND OF SECTIONS

    1. Full section

    2. Offset section

    3. Half section

    4. Broken-out section

    5. Revolved section (aligned section)

    6. Removed section (detailed section)

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    FULL SECTION VIEW

    The view is made by passing the straight cutting

    plane completely through the part.

    OFFSET SECTION VIEW

    The cutting plane is off-set to

    include features that are not in a

    straight line.

    It is possible for the cutting plane

    to change directions, to minimise

    on the number of sectional views

    required to capture the necessary

    details.

    OFFSET SECTION VIEW The view is made by passing the bended cutting

    plane completely through the part.

    Do not show the edge views of the cutting plane.

    HALF SECTION VIEW A half-section is a view of an object showing one-half of the view in section. Symmetrical parts can be shown in half sections.

    Half section without hidden lines

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    HALF SECTION VIEW Half sections are commonly used to show both the internal and outside view of symmetrical objects.

    HALF SECTION VIEW The view is made by passing the cutting plane halfway

    through an object and remove a quarter of it.

    HALF SECTION VIEW A center line is used to separate the sectioned half

    from the unsectioned half of the view.

    Hidden line is omitted in unsection half of the view.

    It is common practice to section a part of an object

    when only small areas need to be sectioned to indicate

    the important details

    BROKEN-OUT SECTION VIEW

    The example shows a broken-out sectional view to indicate a through-hole in a plate.

    The lines indicating the end of the section is a thin continuous line

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    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

    A break line is used to separate

    the sectioned portion from the

    unsectioned portion of the view.

    BROKEN-OUT SECTION VIEW

    There is no cutting plane line.

    Break line is a thin continuous

    line (0.25) and is drawn

    freehand.

    EXAMPLE : Comparison among several section techniques

    Revolved sections show cross-sectional

    features of a part.

    No need for additional orthographic views.

    This section is especially helpful when a cross-section varies.

    REVOLVED SECTION VIEW

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    REVOLVED SECTION VIEW

    Basic concept

    REVOLVED SECTION VIEW

    Basic concept

    Given

    Step 1

    a. Assign position of cutting plane.

    b. Draw axis of rotation in front view.

    Steps in construction

    REVOLVED SECTION VIEW

    Edge view of cross-section

    Steps in construction

    Given

    a. Transfer the depth dimension to

    the front view.

    REVOLVED SECTION VIEW

    Step 2

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    Steps in construction

    Given

    REVOLVED SECTION VIEW

    a. Draw the revolved section.

    Step 3

    b. Add section lines.

    Steps in construction

    Given

    REVOLVED SECTION VIEW

    FINAL PICTURE

    Placement of revolved section

    1. Superimposed to orthographic view.

    Superimposed Break

    2. Break from orthographic view.

    REVOLVED SECTION VIEW 6. Removed section

    Removed section is revolved section.

    Used where space does not enough for revolved section

    Can be located elsewhere on a drawing with properly labeled

    REMOVED SECTION VIEW

    Section view is shown outside the view.

    It may be appropriate to use removed sections, for webs, beams or arms,

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    6. Removed section REMOVED SECTION VIEW

    Note the absence of viewing arrows.

    Example : Revolved vs. removed sections.

    Revolved section Removed section

    REMOVED SECTION VIEW

    Example : Situation that rem