Presentation is loading. Please wait.

Presentation is loading. Please wait.

CHAPTER 4 Dimensioning. adzly anuar © 2001-2004 2 Content Overview Terminology Basic Concept Standard Practice Detail Dimensioning Dimensioning Technique.

Similar presentations


Presentation on theme: "CHAPTER 4 Dimensioning. adzly anuar © 2001-2004 2 Content Overview Terminology Basic Concept Standard Practice Detail Dimensioning Dimensioning Technique."— Presentation transcript:

1 CHAPTER 4 Dimensioning

2 adzly anuar © Content Overview Terminology Basic Concept Standard Practice Detail Dimensioning Dimensioning Technique

3 adzly anuar © Overview Dimension is a way of displaying the size information and feature location on a drawing Generally consist of lines and number: –dimension lines –extension lines –leader lines –number to indicate the measurement 20 Dimension Dimension line Extension line 8 4 R6 MEMB113 | MANUAL DRAWING | CHAPTER 4

4 adzly anuar © Overview Proper dimensioning should give enough information to manufacture the component The dimension should not be redundant / over dimension Example of redundant dimensioning MEMB113 | MANUAL DRAWING | CHAPTER 4

5 adzly anuar © Overview Designs are dimensioned based on two criteria: –Basic sizes and locations of features –Details for construction and for manufacturing The unit of measurement should be consistent – mm or inches –ALL DIMENSIONS IN MM - should be written on drawing MEMB113 | MANUAL DRAWING | CHAPTER 4

6 adzly anuar © Overview Generally two types: –Linear dimension: in mm –Angular dimension: in degree, minutes and seconds Angular dimension Linear dimension MEMB113 | MANUAL DRAWING | CHAPTER 4

7 adzly anuar © Terminology MEMB113 | MANUAL DRAWING | CHAPTER 4

8 adzly anuar © Basic concept Size dimension –May be the overall width of a part or the diameter of a hole Location dimension –May be the length from the edge of an object to the center of a feature Size and location dimensions are used to describe parts for manufacture MEMB113 | MANUAL DRAWING | CHAPTER 4

9 adzly anuar © Basic concept Basic criteria –“What info necessary to manufacture or construct the object?” –E.g. to drill a hole, need to know The diameter of the hole The location of the center The depth of the hole MEMB113 | MANUAL DRAWING | CHAPTER 4

10 adzly anuar © Basic concept Dimensions showing the size of features, such as the height and depth of the part and the diameter of the hole Dimensions showing the location and orientation of features, such as the location of the center of the hole MEMB113 | MANUAL DRAWING | CHAPTER 4

11 adzly anuar © Standard practice Dimension –the numerical value that defines the size, shape, location, etc. of a feature. –Normally height – 3mm and space between line – 1.5mm 20 8 R6 4 MEMB113 | MANUAL DRAWING | CHAPTER 4

12 adzly anuar © Standard practice Dimension line –A thin solid line that shows the extent & direction –Broken for the placing numbers Placement –Dimension placement depends on the space available –Should follow the standard practices MEMB113 | MANUAL DRAWING | CHAPTER 4

13 adzly anuar © Standard practice EITHER OR MEMB113 | MANUAL DRAWING | CHAPTER 4

14 adzly anuar © Standard practice Reading direction –All dimensions and note text must be orientated to read from the bottom of the drawing MEMB113 | MANUAL DRAWING | CHAPTER 4

15 adzly anuar © Standard practice Arrows –Symbols at end of dim. Lines to show limits of the dim. –Uniform in size & style, usually 3mm long & 1/3 as wide Extension line –A thin solid line perpendicular to dim. line, indicating which feature is associated with dim. Visible gap –There should be visible gap of 1mm between feature and extension line MEMB113 | MANUAL DRAWING | CHAPTER 4

16 adzly anuar © Standard practice Leader line - A thin solid line to indicate the feature with which a dimension, note or symbol is associated Diameter symbol Radius symbol Tolerance MEMB113 | MANUAL DRAWING | CHAPTER 4

17 adzly anuar © Standard practice Spacing –The minimum distance from the object to first dim. is 10mm –Min. spacing between dimensions is 6mm –Should be visible gap between extension line and the feature it refers –Extend beyond dimension lines 2mm Minimum dimension line spacing MEMB113 | MANUAL DRAWING | CHAPTER 4

18 adzly anuar © Standard practice Grouping and staggering –Dimensions should be grouped for uniform appearance –Do not use object lines as part of your dimensions Group dimensions MEMB113 | MANUAL DRAWING | CHAPTER 4

19 adzly anuar © Standard practice Extension line –Used to relate a dim. to one or more feature, and usually drawn perpendicular to feature & dim. line –The center of a feature, such as a hole, is located by making the center lines extension lines for the dimension. Extension lines can also cross to mark a theoretical point MEMB113 | MANUAL DRAWING | CHAPTER 4

20 adzly anuar © Standard practice Extension line should not cross dim lines, are not broken when crossing object or other extension lines, and are broken when crossing arrows MEMB113 | MANUAL DRAWING | CHAPTER 4

21 adzly anuar © Standard practice View dimensioning –Dimensions should be kept outside the object Dimension outside the view MEMB113 | MANUAL DRAWING | CHAPTER 4

22 adzly anuar © Standard practice Repetitive feature –The symbol x is used to indicate the number of times a feature is to be repeated Repetitive feature MEMB113 | MANUAL DRAWING | CHAPTER 4

23 adzly anuar © Standard practice Staggered dimensioning A part dimensioned using coordinate dimensions, with a baseline or datum surface as a starting point MEMB113 | MANUAL DRAWING | CHAPTER 4

24 adzly anuar © Standard practice Stagger dimension text MEMB113 | MANUAL DRAWING | CHAPTER 4

25 adzly anuar © Standard practice Others –Avoid dimension to hidden lines –The extension line can cross each other, but not dimension line –The extension line can cross the object, but not the dimension line –Avoid dimensioning inside of object –Centre line cannot be used as dimension line, but can be extended as extension line MEMB113 | MANUAL DRAWING | CHAPTER 4

26 adzly anuar © Detail Dimensioning Dimensioning arcs Foreshortened leaders MEMB113 | MANUAL DRAWING | CHAPTER 4 Dimensioning circle Dimensioning arc

27 adzly anuar © Detail Dimensioning Dimensioning hole Dimensioning a blind hole

28 adzly anuar © Detail Dimensioning Counterbore and countersink hole

29 adzly anuar © Detail Dimensioning Dimensioning slots Dimensioning keyways & keyseats MEMB113 | MANUAL DRAWING | CHAPTER 4

30 adzly anuar © Detail Dimensioning Dimensioning chamfers MEMB113 | MANUAL DRAWING | CHAPTER 4

31 adzly anuar © Dimensioning Technique Geometric breakdown technique MEMB113 | MANUAL DRAWING | CHAPTER 4

32 adzly anuar © Example of the steps to create a dimensional drawing MEMB113 | MANUAL DRAWING | CHAPTER 4

33 adzly anuar © Summary of current and previous ASME standard dimensioning ysmbol Contour dimensioning MEMB113 | MANUAL DRAWING | CHAPTER 4

34 End of Chapter 4 Thank You


Download ppt "CHAPTER 4 Dimensioning. adzly anuar © 2001-2004 2 Content Overview Terminology Basic Concept Standard Practice Detail Dimensioning Dimensioning Technique."

Similar presentations


Ads by Google