Powerpoint dimensioning

A simple PowerPoint on the topic dimensioning.

1. DIMENSIONING by Mr. Curtis Marcelle and Mrs. Kya Morris

2. OBJECTIVES At the end of this lesson, students will be able to: Define the term dimensioning Recognize the rules for proper dimensioning Explain the different types of dimensioning techniques Illustrate the different dimensioning techniques Dimension any plane and irregular figure Value the purpose of dimensioning

3. WHAT IS A DIMENSION? In Technical Drawing, dimensions are: a numeric value expressed in measureable units such as, mm, cm, inches, etc. that define the size, location, or orientation of a geometrical part or object. A method of communication for persons in the industries.

4. WHAT IS THE PURPOSE OF DIMENSIONING? The purpose of dimensions is to provide a clear and complete description or measurement of an object or part. To communicate numeric values for a particular geometrical part or object.

5. WHEN DO WE USE DIMENSION? We use dimensions when details of a particular geometrical part or object is needed. Dimensions should be done on all drawings that will be interpreted later on.

6. HOW DO WE DIMENSION? In Technical Drawing, we must dimension with: Accuracy - correct values must be given. Clearness - dimensions must be placed in appropriate positions. Completeness - nothing should be left out, and nothing duplicated. Readability - the appropriate line quality must be used for legibility.

7. PARTS OF A DIMENSION

8. BASIC TYPES OF DIMENSIONING Linear/Chain Radius/Diameter Aligned Parallel Angular Combined

9. LINEAR/CHAIN A type of dimension that measures in a straight line (either horizontal or perpendicular).

10. ALIGNED This type of dimension measures a line that is at an angle. This dimension is parallel to the angled line.

11. ANGULAR A type of dimension that measures the angle between two lines.

12. PARALLEL All dimensions are parallel to each other and originates from the same line.

13. COMBINED A combination of two or more types of dimensioning

14. RADIUS/DIAMETER A type of dimension that measures the radius or diameter of a circle or arc.

15. RULES FOR DIMENSIONING

16. RULES FOR DIMENSIONING Dimension lines must be kept at least 5mm from the object, and at least 10mm from each other.

17. RULES FOR DIMENSIONING Dimensions that are not needed should not be given. When the overall dimension is given, one of the smaller ones should be eliminated.

18. RULES FOR DIMENSIONING On a part with a circular end, dimension to the centerline. Always give the diameter of a circle, not the radius. Use symbol Ø.

19. RULES FOR DIMENSIONING Always give the radius of an arc, with the abbreviation ‘R’ given before dimension text. Do not use a centerline or a part of an object as a dimension line .

20. RULES FOR DIMENSIONING Do not use an object line as an extension line. Do not cross dimension lines.

21. CONCLUSION We learned: What was a dimension The purpose of dimensions When to use dimensions How to use dimensions Types of dimensioning

22. QUESTIONS?