21-dimensioning-more

Design Project

8.30 – 9.30 Project work (meeting)

Assign a rapporteur

Search in internet, patents and standards about





 bike types, size and design parameters child’s height and weight ranges maximum capacity ??

the regulations about carrying people safety requirements

Prepare the meeting minutes

MAK112E Computer Aided Technical Drawing

Dr C Erdem IMRAK @ 2011 1

Design Project - Minutes

Design group name

Meeting minutes

Date :

Time :

Meeting room :

Participants :

Subject & decisions

1.

2.

3.



3. Principles of Dimensioning

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This week you will learn dimensioning . The steps to follow are:

Functional & Non-functional Dimensions

Principles of Dimensioning

Dimension Placement & Conventions

Dimension Tolerances

Geometric Dimensioning &

Tolerancing

Assignment #2




What is dimension ?

Dimensions

are defined as numerical values expressed in appropriate units of measure and indicated on a drawing and in other documents.




FUNCTIONAL DIMENSIONS

Functional dimensions directly affect the function or working of a product and may be of the size or location types.

A datum is a reference line on the drawing from which a component is dimensioned. In practice, a datum is any functional surface or axis used for manufacture, inspection, location, or assembly purposes.

NON-FUNCTIONAL DIMENSIONS

Non-functional dimensions, NF in Figure, are those dimensions which are used for production purposes but which do not directly affect the function or working of a product. Nonfunctional dimensions usually are not inspected.













PRINCIPLES OF DIMENSIONING

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Dimensions are normally expressed in millimeters.

Dimensions of less than unity should be preceded by zero

Each dimension should appear only once

It should not be repeated on other views.

Dimensions relative to a particular feature should be placed in one view, which shows the relevant features most clearly, rather than spread over several views.




AUTOMATIC DIMENSIONING

Some more powerful CADD systems allow dimensions to be added automatically to a drawing. In a drawing made by hand, there is no necessary or inherent correspondence between the dimensions of the drawn outline and the intended dimensions of the object, which it represents, until a scale has been specified.




Dimensioning Concept

CADD software such as AutoCAD provides three basic types of dimensioning: linear (horizontal, vertical, aligned, rotated, ordinate, baseline and continued), radial and angular.




Dimensioning System Variables

The dimensioning system variables control the appearance of dimensions. You may set these variables on the command line

Variable Value Explanation .

Dimasz <2.5> Controls the size of the dimension arrowhead

Dimgap <1.5> Sets the distance around the dimension text above its line

Dimexe <2.0> Determines how far to extend the extension line

Dimexo <0> Determines how far extension lines offset from origin point

Dimdli <10> Sets the distance between adjacent dimension lines

Dimrnd <0> Rounding dimension text value




Arrowheads




Special Characters

Diameter %%C

Degree %%D

Plus/minus %%P

Ø

°

±

%%C 50 Ø 50

50 %%D 50 °

50 %%P 2 50 ± 2




Text Justification

Centered Above Aligned & Centered

Above


Dr C Erdem IMRAK @ 2011

Outside

16


Text Fitting

Rounding off

Dimensions




DIMENSION TOLERANCES

Tolerance is the total amount that a specific dimension is permitted to vary; it is the difference between the maximum and minimum limits for the dimension. Tolerances can be applied directly to dimensioned features, using limit dimensioning.



Dimensioning in AutoCAD

Before setting dimension style, format

Text Style







To set the dimension varialbes open

Dimension

Style …










24





26


27


28


29




31

Move the mouse on the icon bar

Move right click








Aligned

Radial Angular Continous

Linear

Diameter

Horizonral / vertical

Parallel

Baseline

Geometric tolerance

Leader

Dim text

Position edit

Dimension style dialog box




Geometric Dimensioning & Tolerancing




Geometric Dimensioning & Tolerancing

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Basic Dimensions

Basic dimensions are the theoretical sizes from which limits of size are derived by the application of allowances and tolerances.




Linear Dimensions




Chain Dimensions




Chain Dimensions










Radial Dimensioning










Radial Dimensioning




Angular Dimensioning









Example

1st Select icon

2nd Select point

+

4th point here

3rd Select point MAK112E Computer Aided Technical Drawing


Example




Next Week ;

You will learn multi-view projection. The steps to follow are:

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Projections (ISO-E & ISO-A)

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Multi-view drawings

Projection views (Auxiliary, Detailed etc.)

Sketching 2-D Geometry

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Assignment # 3




Assignment # 2 page : 118

Figure : 76

&

77

You will sketch and complete views

Submit the assignment on time

Load file into NINOVA




Assignment Procedure

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Open MAK112E-Temp template file

Format the drawing file (linetype etc)

Sketch the front view

Complete the top view and the side view

Fill in the title block (name, number, date etc)

Save your (i.e. 301001A2.dwg)

Load the file into NINOVA


Dr C Erdem IMRAK @ 2011

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55

21-dimensioning-more

8.30 – 9.30 Project work (meeting)

Design group name

Dimensions

Before setting dimension style, format

Text Style

To set the dimension varialbes open

Dimension

Style …

&

Assignment Procedure

Related documents

Products

Support

21-dimensioning-more

8.30 – 9.30 Project work (meeting)

Design group name

Dimensions

Before setting dimension style, format

Text Style

To set the dimension varialbes open

Dimension

Style …

&

Assignment Procedure

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