1 technical communications. 2 objectives understanding graphics as a communication tool technical...
TRANSCRIPT
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Technical Communications
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Objectives
• Understanding graphics as a communication tool• Technical sketching• Projections
– Orthographic– Pictorial
• Sketching hints• Lettering
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How Would You Describe This?
• In teams of two, describe using only words• How effective is this approach?
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• Freehand sketches
• Instrument drawings
• Computer drawings and models
Three Basic Types of Technical Drawings
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Introduction to Projections
• Present 3-D objects with 2-D media• Two Basic Categories
Orthographic Pictorial
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Projections: Four Basic Types
Orthographic Projections
Axonometric
Oblique Perspective
Pictorials
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Orthographic Projections
• Collection of 2D drawings• Accurately represent object
• Technical Graphics
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Orthographic Projection
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Defining the SixPrincipal Views
orOrthographic Views
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Which Views to Present?
• General Guidelines
– Pick a Front View that is most descriptive of object
– Normally the longest dimension is chosen as the width (or depth)
– Most common combination of views is to use: Front, Top, and Side View
– Views other than the Principal Views are called Auxiliary Views
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Conventional Orthographic Views
Height
Depth
Width
Front View
Top View
Right Side View
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• Hidden Lines – represent features that cannot be seen in the current view
• Centerlines – represent symmetry and mark the center of circles, the axes of cylinders, and the axes of symmetrical parts, such as bolts
Hidden and Center Lines in Orthographic Projections
• Object Lines – represent visible features for an object
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For Example:
1. Visible
2. Hidden3. Center
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• Front View• Right Side
View• Top View
Creating the Orthographic Projection Sketch
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Step 1 – Lightly Block Three Views
Use very light lines for drawing in
the construction
lines
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Step 2 – Lightly Block Major Features
Use very light lines for
drawing in the construction
lines
• Holes• Arcs• Cutouts
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Step 3 – Refine and Locate Features in All Views
Use very light lines for drawing in
the construction
lines
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Step 4 – Add Final Lines
Use very light lines for drawing in
the construction
lines
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Completed Sketch
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Add Another View
• Sketch the left side view of the object• Compare your view with the others at your table
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Add Another View
• Does yours look something like this?
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Lettering Notes
• Lettering Guidelines – Technical Graphics: Chapter 1
• Lettering Styles– Shape of Letters– Order of drawing lines
• Character Uniformity• Spacing
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Lettering – Vertical Gothic Font
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Sketching Tips: General
• Relax and draw in a direction comfortable to you• Mark end points of the lines to be sketched and
draw between them• Draw long lines as a series of short ones• Use grid paper when available• Follow sketching and text conventions
• Do NOT use a straight edge to draw lines!
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Sketching Tips: Construction Lines
• Use construction lines• Begin by drawing bounding boxes with
construction lines• Make construction lines much lighter and thinner
than finished lines• Identify the major features and overall
dimensions• Leave construction lines on the sketch
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Sketching Tips: Miscellaneous
• Do not shade the drawing – this is not pencil sketching
• Title information is required• Keep views aligned (very important)• Include centerlines on isometrics• Avoid labels on the sketch• Draw neat circles – change page orientation if
needed
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Creating Production Drawings
Goals• Understand production drawings, including detail
drawings and assembly drawings
Reference• Technical Graphics
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Mechanical Production Drawings
• Production drawings (sometimes called Working drawings) are the complete set of drawings specifying the manufacture and assembly of a product.
• Generally consists of multiple drawings, on multiple sheets. A title block appears on each sheet.
• May contain written instructions called specifications.
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Set of Production Drawings
A set of Production Drawings has three main parts:
1. Detail drawings of each non-standard part, usually one part per "sheet".
2. An assembly drawing (or subassembly drawings) showing all parts in a single drawing.
3. A bill of materials (BOM). This is essentially a parts list.
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Reading Production Drawings
• Our first goal is to learn how to read a set of production or working drawings.
• Example: simple fingernail clipper
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Example 1 – Assembly Drawing
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Full Section View
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Detailed Part Drawing: Rivet
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Detailed Part Drawing: Bottom Clipper
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Assembly Drawing
37AU 2006
Example 2 – Butterfly Valve
Isometric
Half-sectionedisometric
Exploded
Individual Part Drawings