Forging new generations of engineers

Forging new generations of engineers
Working Drawings Civil Engineering and ArchitectureTM Unit 2 – Lesson Documentation Forging new generations of engineers Project Lead The Way, Inc. Copyright 2007

Documentation Working Drawings

Working Drawing Once a design has been researched and approved, the part is sent to be prototyped or manufactured. Appropriate documentation is needed to communicate the idea to everyone in the company. This is the most difficult, time consuming, yet the most important part of engineering communication. This documentation is called working drawings.

What are Working Drawings?
Working drawings are a complete set of documents that specify how an object will be manufactured and assembled. Each set should include: Part Drawings Assembly Drawings Parts List Any Special Specifications or Instructions.

Working Drawings Elements of Working Drawings Drawing Layout
Drawing Views Dimensioning Annotations Multiple Features

Drawing Layout Elements of Drawing Layout Sheet Styles and Sizes
Borders Title Block Scale Revision Block

Sheet Styles Drawing Sheets are laid out with a border and title block and can be customized for a company or project.

Sheet Sizes Inch Sizes are based upon standard letter head paper sizes, starting with an 8.5 x 11 sheet (A size), then each size after that doubles. Metric These are based on the A0 size, having an area of 1 square meter and a length to width ratio of 1: 2

International Organization of Standards
Sheet Sizes International Organization of Standards ISO

American National Standards Institute
Sheet Sizes American National Standards Institute ANSI

Borders A border acts as a frame for drawings. Large drawings are broken into zones for locating information on a drawing. These are numbered horizontally and lettered vertically. Letters are upper case and originate in the lower right hand corner.

Border Example Zone Letters Numbers

Title Block A box found in the lower right hand corner of a drawing.
It contains pertinent information on the part Drawing Number Scale Material Title or Description Company Tolerances

Title Blocks Zoning is used to find specific locations on the
Working Drawings Civil Engineering and ArchitectureTM Unit 2 – Lesson Documentation Title Blocks Zoning is used to find specific locations on the drawing. Usually shown in numbers and letters. General notes and information. Located here you will see information on, fillet and rounds, tolerances, and other general information that would take up too much space on the drawing if repeated on every feature. Title of the project. As opposed to a specific part. Remember working drawings are made of many different types of drawings and there are usually more than one sheet that goes with a design. ANSI Large style title block. All title blocks should include the following information. Name of person who checked the drawing. Just like first drafts of papers written in English class, drawings go through many revisions. Scale of the part is important so the person being communicated to can get an idea of what the part looks like. Size of sheet. Very valuable when printing. Another person will check the drawing and approve the part for manufacture. Company name. Many times companies will create their own borders and their logo will appear also. Name of person who did the drawing. Documentation of how many times the drawing has been changed. Specific part name in relationship to the total design. Project Lead The Way, Inc. Copyright 2007

Scale When objects can be drawn using the actual dimensions, it is referred to as full scale or 1:1. Some objects are drawn larger than actual size, so one can clearly see details and dimensions. They can be as large as 10:1.

Scale The bolt is drawn five times larger than actual size. Scale 5:1

Revision Block A revision block is a documentation of all the changes that have occurred on the drawing.

Revision Block Description of the revision made.
Date when drawing was revised. Who revised the drawing. Number of revision.

Drawing Views For clear and accurate dimensioning and specification of a part, the drawing may need a variety of views. The five basic views are: Orthographic Isometric Section Auxiliary Assembly

Orthographic (Multiview Drawings)
Orthographic Projection is also known as a Multiview drawing. Orthographic projection is a way to project a view based on a line of sight that is perpendicular to that view. There are six views to any object as shown in the next slide.

Orthographic (Multiview Drawings)
The arrows represent the line of sight associated with each view.

Orthographic Principal Views
Note how the views are oriented. Each view is adjacent to the other as if they were unfolded from a 3D shape. Front, Top and Right views are used most often. You can see how other views resemble these three except they are not as clear due to hidden lines.

Orthographic Angle of Projection
The example you have just seen is shown in the third angle of projection. This is the standard in the United States and Canada. The rest of the world draws in the first angle of projection. The following slides will show how the views are derived and what they look like.

Orthographic 1st Angle Projection
Views are projected onto planes that exist on the opposite face of the view you want to display. The arrows show the direction of the projection. ISO Symbol

Orthographic 3rd Angle Projection
Views are projected onto planes that exist on the face of that view. Arrows show the direction of the projection ISO Symbol

Orthographic View Selection
Steps in selecting the front view. Most natural position or use. Best shape and characteristic contours. Longest dimensions. Fewest hidden lines. Most stable and natural position. Relationship of other views. Most contours Longest side Least hidden lines Best natural position

Orthographic View Selection
Most natural position. Longest Dimension. Best shape description. No hidden lines.

Orthographic View Selection Numbers
A decision must be made in regard to how many views are needed on a drawing. Generally, three views are needed and, in some cases, only one or two.

Orthographic Example 2 Orthographic views are used instead of three.
Working Drawings Civil Engineering and ArchitectureTM Unit 2 – Lesson Documentation Orthographic Example 2 Orthographic views are used instead of three. Project Lead The Way, Inc. Copyright 2007

Orthographic Example 3 View Orthographic Drawing. Dimensions to show
size and shape. Title Block gives general information about the part.

Placing and Locating Orthographic Views
Parts are evenly spaced. Enough white space is left for dimensioning. Third angle projection is used. (We live in North America.)

Isometric Views An isometric view is a pictorial view inserted in an orthographic drawing. An Isometric, meaning equal measure, is created by rotating the object at equal angles to the projection plane in order to appear inclined and to show three faces.

Note one pictorial view shows
Isometric Note one pictorial view shows height, width and depth. Width and depth lines are drawn at 30 degrees from the horizon line.

Isometric Views Isometric View

Section Views When a part has a lot of interior details, hidden lines can make the part hard to understand and dimension. To see the interior of these parts, we cut some of the part away. This allows for details to be seen clearly, as well as, giving us alternative locations to properly dimension the part.

Sectional Views Types of Sectional Views Half Full Offset Removed
Revolved Broken-out Aligned

Half Section Notice how the cutting plane line runs through the center of the part and there is no arrow head. In a half section, one quarter of the part is cut away. This is done with symmetrical parts where you would like to show the outside, as well as, the inside details.

Full Section A full section is a view that shows what
the object looks like if it were cut in half. A cutting plane line is used to indicate how the front view was cut. It is also labeled in case another section is necessary. The arrows should point in the line of sight as you are looking straight on at the section. Section lines called Hatch lines are used to show where the part is solid. This helps to see the detail that would be normally blocked and only shown as hidden lines.

Offset Section Interior features not in line with each other can be shown in an offset section view. Note how the cutting plane line changes and follows the center of each feature.

Revolved Sections Used when an object has a constant shape throughout the length that cannot be illustrated in an external view. The section is revolved 90 degrees. It may be represented one of two ways, either broken away or not.

Not Broken Away Revolved Section
Section is revolved 90 degrees.

Broken Away Revolved Section
Section is revolved 90 degrees and broken away from part.

Broken-out Section Views
A small portion of an object may be broken away to clarify an interior surface or feature. No cutting plane line is used.

Broken-out Section View
Section exposes the interior surfaces.

Removed Sections A cutting plane is placed through the part where the section is taken. The removed sections are not aligned with the view. Placement is in the surrounding area.

Sections are not aligned
Removed Sections Sections are not aligned with the view.

Aligned Section Views A true projection of a part with inclined ribs, spokes, and arms will be foreshortened. An aligned section view is recommended to acquire accurate dimensions of the part. The cutting plane is bent at an angle as it passes through the object. The section view is then projected 90 degrees from the cutting plane and is in alignment to the original view.

Aligned Section Views View is projected 90 degrees from the cutting
plane and is in alignment to the original view. Cutting plane is bent at an angle

Auxiliary View To accurately view the true dimensions of an inclined surface, one must create a view at 90 degrees from that inclined face. This is referred to as an Auxiliary View. This allows us to view the surface in its true size and shape.

Primary Auxiliary View
In order to see a feature in it’s true size and shape, we must look at it straight on or perpendicular to the plane in which the feature exists. Note that in this view (the auxiliary view) the slotted hole is true size and shape. To obtain this view, the auxiliary must be drawn from the view that allows the line of sight to be perpendicular to the desired feature. Line of sight. Many times a feature on a part cannot be seen in true size and shape. When this is the case we use an auxiliary view.

Secondary Auxiliary View
Sometimes you may have a feature that is oblique in all three views. This type of feature needs two auxiliaries to obtain a perpendicular line of sight on that surface. We now can view a true length line and project with a line of sight perpendicular to the face we would like to see in true size and shape. Line of sight. In the first auxiliary we will try to obtain a view that is looking at the end of one line. Once this auxiliary is projected we then have a true length Line. Line of sight.

Detail Views A drawing of an individual part that contains all the information needed to manufacture the object is referred to as a Detail Drawing. These drawings contain all the specifications, dimensions and views needed for production. A Detail View may be necessary to illustrate small features on a part. This is achieved via breaking out and enlarging the feature.

Detail View The feature is broken out and enlarged for clarity.

Assembly Drawings Many products are composed of several different parts assembled into one. A drawing showing the working relationship of those parts is called an Assembly Drawing. This is achieved using views in the usual positions showing the layout out of the parts. A parts list is included on the drawing to identify the name, material and number of each piece.

Assembly Drawings General Exploded Explosion factor Trails Tweaks

General Assembly Drawings
General Assembly Drawings are a set of drawings that include the detail drawings, assembly drawings and parts list needed in the production of an assembled object.

General Assembly Drawing
Parts List Includes all detail drawings of each part Includes the Assembly Drawing

Exploded Assemblies Identification numbers are generally placed inside balloons and point to the part with a leader line An Exploded Assembly shows all the parts removed from each other and aligned along axis lines Trials show the initial path the components moved along when the view was exploded The explosion factor is the distance the parts have been separated from each other. A parts list is included on the drawing to identify the name, material and number of each piece.

Parts List Item number on the drawing. How many parts are included
Specific part number. All parts will have specific numbers assigned to them. This makes computer data processing easier. Description of part or the name. Item number on the drawing. How many parts are included in the assembly.

Explosion Factor The explosion factor is the distance the parts have been separated from each other.

Trails Trails show the initial path the components moved along when the view was exploded.

Tweaks Adjusting the distance or location of a part in an exploded assembly. After Before

Dimensioning Views and dimensions provide a clear description of the shape and size of parts and their features. Parts are fun to design, but dimensioning the part to be manufactured can be difficult. Dimensioning takes time and patience to get it right. Errors in a drawing will most likely be found in the dimensioning.

Decimal The most common form of dimensioning uses the decimal system. Precision is set by the number of decimal places.

Architectural The Architectural Style of dimensioning is quite different from the decimal. Dimensions are shown in feet and inches. Arrow heads can be the same as decimal dimensioning or can be displayed as architectural ticks.

Engineering The engineering style of dimensions is shown here. The inch units are in decimal and feet and inches are displayed similar to the Architectural style of dimensioning.

Surveyor B Surveying dimensions are given in north and south directions. The example here is said to be North 46 degrees, 48 minutes, 39 seconds West. This indicates the line points in the northwest. Normally a distance is given. A

Dual Position method: Places the metric dimension over the inch
Dual dimensioning is a type that shows both metric and inch units on the same drawing. There are two methods: position and bracket. Dual Position method: Places the metric dimension over the inch dimension. Another acceptable practice is to place the metric dimension before the inch dimension with a slash after the metric dimension. Bracket method: The bracket method places the metric dimension in brackets. The metric dimension can be placed above or to the right. Exactly what the units represent, needs to be noted on the drawing.

Dimensioning Standards Types of Dimensions Linear
Dimensioning Arcs and Circles Reference Dimensions Dimensioning Special Features Methods Rules and Practices Dimensioning Angles Dimensioning Curved Features Coordinate Dimensioning Tolerance

Standards In order for the drawings to be dimensioned so that all people can understand them, we need to follow standards that every company in the world must follow. Standards are created by these organizations: ANSI ISO DIN JIS MIL DOD CEN

Standards Institutions
ANSI - American National Standards Institute - This institute creates the engineering standards for North America. ISO - International Organization for Standardization - This is a world wide organization that creates engineering standards with approximately 100 countries participating.

DIN - Deutsches Institut für Normung - The German Standards Institute created many standards used world wide such as the standards for camera film. JIS - Japanese Industrial Standard - Created after WWII for Japanese standards. CEN - European Standards Organization

The United States military has two organizations that develop standards. DOD - Department Of Defense MIL - Military Standard

Dimensioning Methods Dimensions are represented on a drawing using one of two systems, unidirectional or aligned. The unidirectional method means all dimensions are read in the same direction. The aligned method means the dimensions are read in alignment with the dimension lines or side of the part, some read horizontally and others read vertically.

Dimensions are aligned
Aligned Dimensions Dimensions are aligned with the dimension lines.

Unidirectional Dimensions
All dimensions and notes are horizontal and read from the bottom of the sheet.

Types of Dimensions There are two classifications of dimensions: size and location. Size dimensions are placed in direct relationship to a feature to identify to specific size. Location dimensions are used to identify the relationship of a feature to another feature within an object.

Size and Location Dimensions
Size dimensions Location dimensions

Rules and Practices Accurate dimensioning is one of the most demanding undertakings when designing parts. Use the checklist to insure you have followed the basic dimensioning rules.

Dimensioning Checklist
Each dimension should be written clearly with only one way to be interpreted. A feature should be dimensioned only once. Dimension and extension lines should not cross. Dimension each feature. Dimension features or surfaces to a logical reference point.

Dimension Checklist Dimension circles with diameters and arcs with a radius. A center line should be extended and used as an extension line. Dimension features on a view that clearly shows its true shape. Dimension with enough space to avoid crowding and misinterpretation.

Dimension Checklist Extension lines and object lines should not overlap. Dimensions should be placed outside the part. Center lines or marks should be used on all circles and holes.

Linear Dimensioning The accuracy of the final product is determined by the dimensions on the drawing. If all the dimensions originate from a common corner of the part, the object will be more accurate. This is referred to as Datum Dimensioning. Datums insure the tolerance or errors in manufacturing do not accumulate.

Linear Dimensioning Dimensioning from feature to feature is known as Chain Dimensioning. It is commonly used and easy to lay out. It does have possible consequences in the manufacturing of a part. Tolerances can accumulate making the end product larger or smaller than expected.

Chain Dimensioning This step can be .490 To .510 wide
The chain dimensioning layout can have an effect on the final length of the part ranging from 1.47 to 1.53 This step can be .490 To .510 wide This step can be .490 To .510 wide This step can be .490 To .510 wide The chain dimensioning layout can have an effect on the final height of the part ranging from .72 to .78 This step can be .240 To .260 tall This step can be .240 To .260 tall This step can be .240 To .260 tall

Placing an overall dimension will limit the chain effect of the
Chain Dimensioning Placing an overall dimension will limit the chain effect of the Tolerance build up Placing an overall dimension will limit the chain effect of the Tolerance build up.

Datum Dimensioning This distance can be .990 to 1.010 wide
The dimensions originate from a common edge (DATUM) of the part The dimensions originate from a common edge (DATUM) of the part This distance can be .990 to wide This step can be .490 To .510 wide

Dimensioning Angles Angled surface may be dimensioned using coordinate method to specify the two location distances of the angle. Angled surfaces may also be dimensioned using the angular method by specifying one location distance and the angle.

Dimensioning Angles Coordinate Method Angular Method

Dimensioning Arcs and Circles
Arcs and circles are dimensioned in views that show the arc or circle. Arcs are dimensioned with a leader to identify the radius. In some cases a center mark is included. Circles should have a center mark and are dimensioned with a leader to identify the diameter.

Dimensioning Curved Features and Arcs
Small arcs do not need center marks. Arrow can be outside. Large Arcs use center marks. Use a capital “R” for dimensioning arcs. Or the arrow can be inside for small arcs.

Diameters A full circular object should be dimensioned
using it’s diameter. Holes should use hole notes. Cylindrical parts may show their diameters in this manner. Dimensioning on the right side view would be too crowded. This specification calls for a hole with a .5 diameter and 1.00 deep

Chords may be dimensioned in one of
the following ways.

Dimensioning Curved Features
Points are placed along the contour and are dimensioned from the datum Datum

Reference Dimensions Designates more than one of the same feature.
In this case it is identifying there are two identical holes

Chamfers External chamfer for 45 degree chamfers
only. There are two options. External chamfer for angles other than 45 degrees. Internal chamfers.

Fillets and Rounds Use a capital “R” for dimensioning the arc. Fillets
Small arcs do not need center marks. Arrow can be outside the arc. Rounds Large arcs use center marks.

Conical Tapers

Slot Dimensioning The two methods shown on the left are the acceptable
methods for dimensioning slotted holes.

Hole Location: Polar Coordinates
Polar dimensioning locates features by the use of angles

Rectangular Coordinates
Rectangular coordinates use linear dimensions to dimension the hole locations. multiple holes are dimensioned from another

Rectangular Coordinates
Linear Coordinates are used to locate hole dimensions.

Keyways Keyway Keyways Shaft Hole

Tolerance Dimensioning
Perfection is difficult to obtain. A tolerance is associated with dimensions on a drawing to illustrate the permissible variation in size or location. A tolerance specifies how much the dimension may vary from the designated size on the drawing.

Tolerance Limits The largest size an object can be made to is the upper limit. The smallest size an object can be made to is the lower limit. Upper limit .126 Lower limit .125 Upper limit Is .380 Lower limit Is .373

Dimensioning Tolerances
If your limits deviate above and below your basic size you have bilateral dimensioning. This dimension is unilateral because the size may only deviate in one direction. Limit Dimensioning shows the size of the upper limit and the lower limit.

Allowances Some parts fit together requiring an
allowance to be specified. It is the tightest possible fit between two parts. If this part is made larger than .380, it will not fit together properly.

Alphabet of Lines Short Break Line: A freehand
drawn line that shows where a part is broken to reveal detail behind the part or to shorten a long continuous part. (See example of Long Break Line on the next slide.) Hidden Line: Lines used to show interior detail that is not visible from the outside of the part. Object Line: Thick lines about .6mm(.032in) that show the visible edges of an object. Center Line: Lines that define the center of arcs, circles or symmetrical parts. They are half as thick as an object line. Section Lines: Lines are used to define where there is material after a part of the object is cut away. Construction Line: Very lightly drawn lines used as guides to help draw all other lines and shapes properly. Usually erased after being used.

Alphabet of Lines Long Break Lines: Break lines are used
To indicate we have shortened the drawing to use our space more efficiently. Dimension lines are used to show distance. Arrows are drawn on the ends to indicate where the dimension line starts and ends. The actual distance is placed in the middle of this line. Dimension lines are used in conjunction with extension lines to properly dimension objects. Extension lines are used to show where a dimension starts and stops on an object. The line should begin about 1/16” away from the part to prevent confusion with the object lines Cutting Plane Line: A line used to designate where the part has been cut away to see detail. The arrows point in the direction that you are looking. Leader lines are used to show dimensions of arcs or circles. They are also used to connect notes with features. The line with the arrowhead should be diagonal while the Line connecting to the note is horizontal. How many lines from the previous slide can you identify here?

Line Types and Specifications
Arrow heads point directly to the object that is being dimensioned or the extension lines at the end of the dimension. Arrow heads are made 3 times as long as they are wide. Each succeeding dimension line should be 6mm from the previous one. Extension lines are used to establish the extent of the dimension. Arrows from the dimension line should touch the extension line. Extension lines should have a small space between the end and the object that is being dimensioned. The extension line should also extend 3mm beyond the last dimension line noted. The dimensioning system used here is unidirectional. This is the most common. Another system you may see is aligned. If this drawing were using the aligned system the dimension, we are pointing to would be read horizontally from the right of the drawing or turned counter clockwise 90 degrees. Dimension lines are used to identify distances of features. It has arrow heads at the end to identify the extents. There is a break in the middle to place the dimension. Dimension lines should be 10mm away from the object that is being dimensioned.

Annotation Local notes identify specific features that need a special operation. Hole notes are one such example. This note is placed with leaders at the location of the feature it pertains to. General notes are information that pertains to the entire drawing, unless specified in a local note. General notes are usually placed in the title block.

with numbers and symbols.
Hole Dimensioning Holes are specified with numbers and symbols. Diameter Through Depth Counterbore or Spotface

Hole Dimensioning Finish Mark Countersink

Hole Dimensioning castings to create a flat surface for bolts.
A countersunk hole has an angular cut on the top edge to allow flathead screws to sit below the surface A spotface is a shallow cut used on castings to create a flat surface for bolts. Boss is a raised surface used in castings for reinforcement. Finished on top to create a flat surface for the bolt to seat. A blind hole is drilled to a specific depth. A counter bored hole has a step so the head of a bolt can sit below the surface. Through hole is drilled completely through the material.

AMERICAN NATIONAL FORM
Threads: Forms PITCH DEPTH METRIC THREAD UNIFIED THREAD FORM AMERICAN NATIONAL FORM WHITWORTH THREAD ACME THREAD SHARP-V THREAD

Threads: Forms Continued
PITCH PITCH 1/2 PITCH 1/2 PITCH SQUARE THREAD PITCH BUTTRESS THREAD ROLLED THREAD

Thread Notes Finally THRU or a depth may M for Metric Nominal Diameter
This number can be 3,4,5,6,7,8,9. It is the grade of tolerance in the threads from fine to course. The H is for allowance G would be a tight allowance and H is no allowance. Prior to THRU you may have an LH for left hand thread. Finally THRU or a depth may be specified. M for Metric Nominal Diameter Pitch of the threads. Notes the threads are cut all the way through the hole. Depth can be specified here as well as LH for left hand thread. Identifies course or fine thread. In this case course. F for fine. Major Diameter Threads per Inch Threads are dimensioned with the use of local notes. We will discuss two methods: the ISO and the Unified National Thread method.

Geometric Dimensioning and Tolerancing Symbol
Size of the tolerance. Datum from which tolerance is measured from. Type of geometry to be toleranced. Datum point referred to.

Welding Symbols Indicates size of Arrow shows the weld.
location of weld. Indicates type and location of weld.

Specifications: General
Specifications are a set of instructions that give very definitive information regarding material, safety requirements, packaging, work processes, or any other information that may be specific to the part. Specifications may be written out or set up in chart form. Specification sheets are most commonly seen in architectural drawings due to the quantity of parts and materials.

Specifications: Proprietary
Proprietary specification sheets are the same as general. The exception comes in that a specific company and product are called for. For example, a special pump may be needed for a design. The specification sheet would have to show: The Company: Flight Model number: BS 2400 Description: Submersible Pump Specifications: 1.8m3 Water per minute, Head of 200m Easily relocated.

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