CAD and Drafting Standards Working Drawings

Transcription

1 CAD and Drafting Standards Working Drawings Gregory Mocko

2 Introduction 2 The purpose of drawing or generating a CAD document is to communicate Essentially, since communication is the goal, some standards must be used, otherwise misunderstandings occur. There are several standards, namely ASME Y14.5 and other US standards and ISO norms. They provide guidelines on how to communicate unambiguously. Page 2 of 13

3 Overview 3 Working drawings are what the design is implemented from A detail drawing is of a single part of detail Specification are written instructions that go with the drawings Specifications may be written on the drawings or on a separate sheet Tolerances, mating, contact surfaces, proper motion must be insured this is completed by designer not drafter They are legal documents Describe what will be made They must be revised and modified under control ($)

4 Basic Elements of Working Drawings 4 Dimension and units Remain consistent across all components Dual dimensions may appear note not continuous Layout of drawing Identify required views Use scale Title block Notes Checking a drawing A designer and drafter Result in a better product Assembly Drawings All parts that are made must be fit together

5 Title Blocks 5 Name & Address of company Title of Drawing Drawing Number Names and dates of drafter, checker, issue date, Approval Block Predominant Drawing Scale Sheet Number

6 Bill of Material 6 Name of part Part Material # of times the part is used Part Number (company assigned) Located lower right corner (ANSI)

7 Multi-view Working drawing 7

8 Assembly drawing 8 All parts drawing in their operating position Part list or Bill of Material Leader lines with balloons Machining and assembly operation specification

9 Assembly drawing 9

10 Revision Block 10 Because design changes/correction occurs Contains date, names, description, change number and approval

11 Scale 11 Placed in the title block More than one scale then its mentioned near the detailed drawing

12 Tolerance Specification 12 Placed in title block General tolerance note for dimensions that don t have specified tolerance

13 Working Assembly Drawing 13 Combined detail drawing and assembly drawing Usually Sectioned view Have mainly standard/purchased parts

14 Working Assembly Drawing 14

15 Alphabet of Lines 15 Object Lines Hidden object lines Center lines, axes Extension lines, arrows Cutting planes for sectioned views

16 Drawing Rules 16 Unless absolutely compelled to do otherwise, honor the conventional rules of orthographic projection with top front and side views arranged as shown in the second figure of this presentation Use appropriate line weights (see previous slide) Normally, try dimension cylinders in views where they appear as rectangles. Dimension and locate holes where they appear as circles Always indicate centerlines for cylinders and holes Always locate circles (and cylindrical features) from their centers. Dimension Holes by specifying the DIAMETER Dimension rounds by specifying the RADIUS

17 Drawing Rules 17 Make sure tolerances are specified where needed and appropriately Do not over define the tolerances, cost will be prohibitive Make sure someone else can understand your drawing and can produce a 3D rendition from your CAD data Do not forget to specify materials Write who has done the design and is responsible for it Put date of design, file name and location to find it later on Number pages if multiple pages are needed, put titles and refer to appropriate drawings for clarifications, additional information.

18 WORKING DRAWINGS EXAMPLE 18

19 19 Isometric Views Front View

20 Exploded Assembly 20

21 Part 1: Forward Arm 21

22 Part 2: Yoke Brace 22

23 Part 3: Support Link 23

24 Part 4: Hex Bolt 24

25 Part 5: Hex Bolt (160mm) 25

26 Part 6: Hex Bolt (260mm) 26

27 Part 7: Hex Bolt (360 mm) 27

28 Layout Drawing 28

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