Chapter 20 Working Drawings Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Components of Engineered Product Sketches- document initial design solutions Models- represent the final design solutions Drawings- deliverables for production Production/ Working Drawings Information required to make the part or assembly of a design

How much does it cost to make a design change? Models and drawings are used as _______tools, to manufacture products, and show how complex assemblies are put together. How much does it cost to make a design change?

Complete Set of Working Drawing Objectives Completely describe parts visually and dimensionally Show parts in assembly Identify all parts Specify standard parts How do we accomplish these objectives? ________________ Drawings ____ __________ Drawings

Assembly Drawings A title block Drawing showing all the standard and non-standard parts A bill of Materials (BOM)

Sub-Assembly Drawings A title block Drawing showing all the standard and non-standard parts A bill of Materials (BOM)

Detail Drawings A title block Fully defined part (dimensioned and toleranced) GD&T Manufacturing information Weld Symbols Surface Texture Process Material

Standard Parts Not detailed but shown in assembly (Fasteners, bushings, bearings etc.)

4 Major Parts of assembly drawings All parts drawn in operating position Parts list (BOM) showing: Leader lines w/ balloons assigning detail #’s Machining & assembly operations w/ critical dimensions related to these functions

Communicate how part interrelate Assemblies Communicate how part interrelate Exploded vs. Sectioned http://www.kosmix.com/topic/ball_valve

Rules for Assembly drawings: Minimum # of views to describe assembly Dimensions not shown unless necessary to provide overall assembly dimensions or assist in machining operations necessary for assembly (field weld) Hidden lines omitted except when needed for assembly or clarity Phantom lines show movement or assembly movements

Types of Assembly drawings: Outline Assembly- exterior shape Sectioned- interior shape Pictorial- Isometric view

Used to record ALL general information necessary for working drawings Title Blocks: Used to record ALL general information necessary for working drawings Name and Address of Company Title of Drawing Drawing # Names and Dates of designer, checker, issue date, contract # etc. Design approval, when subcontractors are used Additional approval block Predominant drawing scale J. Drawing Sheet size letter designation K. Actual or estimated weight of the item Sheet # of multiple sheets in set Other information (Surface finish, hardness, heat treatment etc.)

Listed in order of importance Manufactured or Purchased Part Parts lists or Bill of Materials (BOM): ANSI standards places it in the lower right corner above the titleblock Listed in order of importance Manufactured or Purchased Part Information of standard parts is included (Catalog #, part name and size, etc.) Information Provided: Item # Name of part Part Material Quantity Company assigned part # Other information (weight, stock size, etc.)

Zones Used on large sheets for reference purposes (Letter and # designation used to specify location on drawing)

Revision Block Per ANSI standard placed in upper right corner of drawing for room to expand down What does it document? Design Changes Tooling Changes Customer Requests Errors, etc. What does it contain? Date Name of person making change Description of Change Change # Approval Zone one drawing where change is taking place

Engineering Change Orders/ Notes (ECO’s/ ECN’s) Formal request for making a change to existing engineering drawings Should contain: Sketches w/ copy of original drawing Written Description of Change Reference # to trace change in future

and near any view not at that scale Scale Specifications Per ANSI standard placed in title block to call out majority of scales shown in each view, and near any view not at that scale (If Metric is used somewhere near the title block METRIC or SI should be clearly visible) Common English Scales? Full 1:1 Half 1:2 Quarter 1:4 Eighth 1:8 Double 2:1 Common Metric Scales? Tenth 1:10 Twentieth 1:20 Fiftieth 1:50 Hundredth 1:100

Tolerance Specifications Tolerance Dimensions General Tolerance Note in Title block GD&T Classes of Fit ANSI Standards: One place decimal dimension = ± .1 Two place decimal dimension = ± .03 Three Place decimal dimension = ± .010 Angular Tolerances = ± .1˚ Interpret Dimensioning and Tolerancing per ASME Y14.5-2009

Redlining $$$$$$$$$$ Drawing is a legal contract Thorough Check by several people for errors and consistency with industry and company standards Why do companies have dedicated checkers? $$$$$$$$$$ Drawing is a legal contract between producer and client Designer/ Drafter/ Engineer/ Checker check what? Choice of views Consistency Dimensions Approvals Tolerances Revisions Clarity Scale Standard part specifications Accuracy Notes Title block Parts list

Used when several similar parts have common features (Family of Parts) Tabular Drawings Used when several similar parts have common features (Family of Parts) U bolts Casters Air Cylinders

Threaded through supports Homework Figure : 20.49 Wheel Support CHANGES: 1” HUB O.D. Threaded through supports ½” washer on nut end

Tolerancing Fits of Size

Tolerancing Fits of Size

Smallest Hole = 1.0000 Largest Shaft = -1.0035 Interference = -.0035 For 1” or 1.000” FN2 fit what are the tolerances? Hole in Support 1.000 + .0007 = 1.0008 Upper limit Hole in Support 1.000 + .0000 = 1.0000 Lower Limit Outer Diameter of Bushing 1.0035 Upper limit Outer Diameter of Bushing 1.0025 Lower Limit Smallest Hole = 1.0000 Largest Shaft = -1.0035 Interference = -.0035 FN What?

Smallest Hole =.6250 Largest Shaft = -.6230 Clearance =.0020 RC What? For 5/8” or .6250” RC1 fit what are the tolerances? Hole in bearing .6253 Upper Limit Hole in bearing .6250 Lower Limit Shaft of shoulder screw .6230 Upper limit Shaft of shoulder screw .6210 Lower Limit Smallest Hole =.6250 Largest Shaft = -.6230 Clearance =.0020 RC What?