Lecture 8 - Technical Drawing: Dimensioning PDF

Engineering Design and Material Selection Lecture 8 - Technical drawing: Dimensioning Dr Tino Stankovic Prof. Dr. Kristina Shea Prof. Kristina Shea 1  Course Schedule Week/ Topic...

Engineering Design and Material Selection Lecture 8 - Technical drawing: Dimensioning Dr Tino Stankovic Prof. Dr. Kristina Shea Prof. Kristina Shea 1  Course Schedule Week/ Topic Case study Quiz Lecturer Dates 1 Introduction and Sketching 2 Introducing Engineering Design Health Prof. Dr. Kristina Shea 3 Technical Drawing: Projections and Cuts 4 CAD: Introduction and Modeling Operations 5 CAD: Features and Parametric Modeling Future Mobility 6 CAD: Freeform Modeling Dr. Tino Stankovic 7 CAD: Assemblies and Standard Mechanical Parts X (45 min) 8 Technical Drawing: Dimensioning Health 9 Sustainability in Engineering Design 10 Materials and their Properties 11 Manufacturing Processes with Focus on Additive Manufacturing Sustainable Materials Prof. Dr. Kristina Shea 12 Material Selection 13 Review and Q+A X (75 min) Prof. Kristina Shea Engineering Design + Computing Laboratory 2  Learning Objectives ▪ Understand the different types of dimensioning and when and where to use which type ▪ Be able to give and read dimensions in technical drawings according to the norms ▪ Learn how to give and read simplifications for dimensions ▪ Learn how to dimension special elements, e.g. threads Prof. Kristina Shea Engineering Design + Computing Laboratory 3  3D Model of a Mechanical Ventilator Prof. Kristina Shea Engineering Design + Computing Laboratory 5  Mechanical Ventilator Main Parts and Functions Prof. Kristina Shea Engineering Design + Computing Laboratory 6  How should we add dimensions to a drawing? Prof. Kristina Shea Engineering Design + Computing Laboratory 8  Technical drawing: process 1. Choose the principal (front) view 2. Choose other required views 3. Draw the views 4. Add dimensions 5. Verify Prof. Kristina Shea Engineering Design + Computing Laboratory 9  What are elements of dimensioning? Leader line Extension line Symbol Ø12 Dimensional value Reference line 350 450 150 Indicator Dimension line Terminator of origin Prof. Kristina Shea Engineering Design + Computing Laboratory 10  Extension and Dimension Lines Terminator Extension line Dimension line Prof. Kristina Shea Engineering Design + Computing Laboratory 11  Example for Simple Dimensioning not allowed to add unnecessary dimensions Prof. Kristina Shea Engineering Design + Computing Laboratory 12  Dimensioning for… function manufacturing inspection Prof. Kristina Shea Engineering Design + Computing Laboratory 13  Dimensioning Process 1. Define outside dimensions 2. Define functional dimensions 3. Add required manufacturing dimensions 4. Add any dimensions for inspection 5. Add auxiliary dimensions 6. Verify the dimensioning Prof. Kristina Shea Engineering Design + Computing Laboratory 14  Functional and Non-Functional Dimensions NF F F F NF Prof. Kristina Shea Engineering Design + Computing Laboratory 15  Rules for Dimensioning Prof. Kristina Shea Engineering Design + Computing Laboratory 16  How many dimensions have to be added for the dimensioning to be complete? 4 missing at In Prof. Kristina Shea Engineering Design + Computing Laboratory 17  Auxiliary Dimensions () () Prof. Kristina Shea Engineering Design + Computing Laboratory 19  First Example: Cover plate Prof. Kristina Shea Engineering Design + Computing Laboratory 20  Cover plate: functional dimensions Parts-bolt interaction Overlap with the bearing 𝜙 ℎ Bearing centering However, this is achieved with the housing!!!! Prof. Kristina Shea Engineering Design + Computing Laboratory 21  Cover plate: outside dimensions Prof. Kristina Shea Engineering Design + Computing Laboratory 22  Cover plate: functional dimensions Functional Prof. Kristina Shea Engineering Design + Computing Laboratory 23  Cover plate: manufacturing dimensions Manufacture dimension Prof. Kristina Shea Engineering Design + Computing Laboratory 24  Orientation of Dimensional Values 30° 30° 60° 60° 56 56 30 56 30 56 ° ° ° ° 60 56 60 56 56 56 56 56 56 60° 30° 30° 56 56 6 56 ° 56 ° 55 56 56 55 60 56 ° 60 ° 5° 5° Prof. Kristina Shea Engineering Design + Computing Laboratory 25  Second example: motor holding plate Holdingplate motor Housing Prof. Kristina Shea Engineering Design + Computing Laboratory 26  Motor holding plate: outside dimensions Prof. Kristina Shea Engineering Design + Computing Laboratory 27  Motor holding plate: functional dimensions Prof. Kristina Shea Engineering Design + Computing Laboratory 28  Motor holding plate: manufacturing dimensions Prof. Kristina Shea Engineering Design + Computing Laboratory 29  Dimensioning of Special Elements Bevels and countersinks 1 45° or 90° only Prof. Kristina Shea Engineering Design + Computing Laboratory 30  Arrangement of Dimensions: Chain and Parallel Dimensioning Chain Parallel Take EF to over dimensio Prof. Kristina Shea Engineering Design + Computing Laboratory 31  Arrangement of Dimensions: Combined Dimensioning Chain Running Parallel Prof. Kristina Shea Engineering Design + Computing Laboratory 32  Arrangement of Dimensions for Internal and External Dimensions Prof. Kristina Shea Engineering Design + Computing Laboratory 33  Representation of Internal Threads Major Minor Major Minor Prof. Kristina Shea Engineering Design + Computing Laboratory 34  Representation of External Threads Minor Major Prof. Kristina Shea Engineering Design + Computing Laboratory 35  Representation of Thread Run-Outs Root I Depth of thread Prof. Kristina Shea Engineering Design + Computing Laboratory 36  Connection of Threaded Parts - Hatching + = External Internal thread thread Combined Prof. Kristina Shea Engineering Design + Computing Laboratory 37  How many threaded holes are there on the shown views? A. 11 B. 10 C. 1 D. 9 Prof. Kristina Shea Engineering Design + Computing Laboratory 38  Checklist for verifying dimensioning: ▪ Here are some questions that guide you in verifying the dimensioning: ▪ Are there outside dimensions? ▪ Are there functional dimensions? ▪ Are all geometric elements defined? ▪ Does it match the desired manufacturing process? ▪ Are the relevant dimensions for inspection shown? ▪ Have you reduced chains and is there is no over-dimensioning? ▪ Do the dimensions follow the norms? ▪ Are all of the dimensions clear and readable? ▪ Tip: Try to resketch the part based only on the dimensions. Prof. Kristina Shea Engineering Design + Computing Laboratory 39  Checklist for verifying your technical drawings (Lecture 3) Here are some questions that can guide you in verifying the quality of technical drawings: ▪ Is the principal view the most informative view? ▪ Are there sufficient views (projections and cuts) to fully define the geometry? ▪ Are the smaller details clearly visible? ▪ Are the views positioned correctly? ▪ Are the proportions and the scale correct? ▪ Are you satisfied with it? Prof. Kristina Shea Engineering Design + Computing Laboratory 40  Drawing comparison 1 A B Better cuz readable Prof. Kristina Shea Engineering Design + Computing Laboratory 41  A Drawing comparison 2 Both suck B is slightly B better Prof. Kristina Shea Engineering Design + Computing Laboratory 42  A Which drawing is better? Both such bad for manufacturing B Ang 0 Prof. Kristina Shea Engineering Design + Computing Laboratory 43  Case Study Mechanical Ventilator – Wrap-Up The Need Phase 1: Phase 2: Phase 4: Phase 5: Concept System-Level Phase 3: Testing & Production Phase 0: Planning Detail Design Development Design Refinement Ramp-Up Prof. Kristina Shea Engineering Design + Computing Laboratory 44  Dimensioning – Wrap Up Dimensions in a drawing ensure the function, manufacturing and inspection of a part. The norms define how dimensions are placed on drawings. It is up to you to create a complete and unambiguous geometric definition in your drawing. Always verify your drawing and check that the dimensioning is complete and not over dimensioned. CAD tools can help you to create drawings but it is up to you to validate them! Prof. Kristina Shea Engineering Design + Computing Laboratory 45  Exercise 8: CAD Drafting Understanding a part’s function: Can you create a completely dimensioned, unambiguous drawing of this linear guide from a 3D model in NX? Lathe turning machine Prof. Kristina Shea Engineering Design + Computing Laboratory 47