UNIVERSITY OF PUERTO RICO AT HUMACO DEPARTMENT OF PHYSICS ENGINEERING GRAPHICS I Traditional tools Dr. Walter López Moreno 1

Introduction to Engineering Graphics Importance of technical graphics Traditional engineering design & Changes in the engineering design process Technical drawing tools Standards ANSI standard sheet sizes Basics: Line weight & pencil grades Alphabet of lines

Importance of technical graphics " the engineer, scientist, or technician who is ignorant of or deficient in the principal mode of expression (that is, the universal graphic language) in his or her technical field is professionally illiterate."     - Page 8. Principles of Technical Drawing This statement summarizes the importance of technical graphics.

Importance of technical graphics Technical drawings: A language used in the design process for communicating, solving problems, quickly and accurately visualizing objects, and conducting analysis A graphical representation of objects and structures and is done using freehand, mechanical, or computer methods -The drafting and design phases comprise more than 52 percent of the engineering process. Users of engineering and technical graphics in industry

From traditional “linear” design process to new“concurrent” design process Traditional: A linear, segmented activity involving problem identification, preliminary ideas, design refinements, analysis, optimization, and documentation Concurrent: A team activity involving coordination of the technical and non-technical functions of design and manufacturing within a business The CAD database becomes a communication medium.

Samples of drawing conventions and standards

Architectural Drawing Lewis Park (Second Floor) downstairs of 2, 3 and 4 bedroom

Manual drafting tools for technical drawing Mechanical pencils: 0.7 and 0.5 mm, or 0.5 and 0.3 mm combinations; Pencil grades – HB and H, or F and 2H combinations) Compass and one divider One set of 45- and 30/60-degree triangles Scales (one English unit and one Metric unit) Irregular curve (French curve) Protractor One good eraser

Use of drafting tools – a few examples

Standards Organizations involved in developing the standards for technical drawings: ANSI (American National Standards Institute) ASEE (American Society for Engineering Education) SAE (Society of Automotive Engineers) ASME (American Society of Mechanical Engineers) ISO (International Standards Organization) American National Standard Drafting Manual ANSI is the governing body that sets the standards used for engineering and technical drawings ANSI standards are periodically revised to reflect the changing needs of the industry and technology The Y series of ANSI standards are the ones most important for technical drawing. ISO is made up of a group of standards institutes from 145 different countries

Some Important ANSI standards ANSI Y14.1 (1980) Drawing Sheet Size and Format. ANSI Y14.2M (1979) Line Conventions and Lettering. ANSI Y14.3 (1975) Multiview and Sectional View Drawings ANSI Y14.5M (1982-1994) Dimensioning and Tolerancing. ANSI Y14.6 (1978) Screw Thread Representation ANSI Y14.6aM (1981) Screw Thread Representation (Metric Supplement) ANSI Y14.7.1 & Y14.7.2 (1978) Gear Drawing Standards

ANSI Standard Sheet Sizes & typical title block layouts

Pencil grades and Line weight Remember that Accuracy, Neatness, and Speed count in technical drawing

Alphabet of lines (1)

Alphabet of lines (2)