All that begins... peace be upon you

Transcription

1 All that begins... peace be upon you

2 Faculty of Mechanical Engineering Department of Thermo Fluids SKMM 1922 Introduction to Mechanical Engineering Mechanical Design «An excerpt (mostly) from Jonathan Wickert & Kemper Lewis (2013)» Abu Hasan ABDULLAH November 2017

3 Outline 1 Introduction 2 The Design Process Requirements Development Conceptual Design Detailed Design Production 3 Manufacturing Processes Casting Forming Machining Joining Finishing abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 1 / 18

4 Introduction National Academy of Engineering (NAE) has identified 14 Grand Challenges facing the global engineering community and profession in the 21 st century: 1 Make solar energy economical 2 Provide energy from fusion 3 Develop carbon sequestration methods 4 Manage the nitrogen cycle 5 Provide access to clean water 6 Restore and improve urban infrastructure 7 Advance health informatics 8 Engineer better medicines 9 Reverse-engineer the brain 10 Prevent nuclear terror 11 Secure cyberspace 12 Enhance virtual reality 13 Advance personalized learning 14 Engineer the tools of scientific discovery These challenges are reshaping how engineers view themselves, how & what they learn, & how they think, broadening the perspective of engineers and how they view the communities they impact. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 2 / 18

5 Introduction The process of developing something new and creative lies at the heart of the engineering profession and while these challenges span many scientific and engineering disciplines, the principle connecting them all is design. Multidisciplinary teams will need to design innovative and effective solutions to meet the variety of subchallenges that each challenge embodies. This chapter introduces you to some of the issues arising when a new product is designed, manufactured, and patented.... and in later chapters you will see how approximation, mathematics, and science are applied to design problems to reduce trial and error. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 3 / 18

6 Introduction Figure 1: Topics emphasized in this chapter (shaded boxes) relative to an overall program of study in mechanical engineering. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 4 / 18

7 The Design Process Mechanical design is the systematic process for devising a product or system that meets the society s technical needs Engineers conceive solutions to those problems and turn their conceptions into functioning hardware. Mechanical design process can be broken down into four major stages 1 Requirements development 2 Conceptual design 3 Detailed design 4 Production which is further detailed in Figure 2. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 5 / 18

8 The Design Process Figure 2: Flowchart of the prototypical mechanical design process. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 6 / 18

9 The Design Process Requirements Development Engineering design begins when a basic need, e.g. a technical need from a certain market or a basic human need like clean water, renewable energy, or protection from natural disasters has been identified. A design engineer then develops a comprehensive set of system requirements considering the following issues: Functional performance: What the product must accomplish Environmental impact: During production, use, and retirement Manufacturing: Resource and material limitations Economic issues: Budget, cost, price, proft Ergonomic concerns: Human factors, aesthetics, ease of use Global issues: International markets, needs, and opportunities Life cycle issues: Use, maintenance, planned obsolescence Social factors: Civic, urban, cultural issues which are essentially the constraints that the design must eventually satisfy. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 7 / 18

10 The Design Process Conceptual Design Product design requires engineers who are part rational scientists and part innovative artists and design engineers will be working in collaborative team. Initially the team needs to generate a wide range of potential solutions to the problem at hand; this process is guided by divergent thinking a diverse set of creative ideas. Figure 3: The generation and selection of ideas in conceptual design. Once a set of concepts has been generated, the process is guided by convergent thinking, as engineers begin to eliminate ideas and converge on the best few concepts. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 8 / 18

11 The Design Process Conceptual Design The team will need to define, innovate, analyze in order to converge its way to the best concept. Computer models and prototype hardware might also be produced at this stage to help with the selection process. This stage culminates in identifying the most promising design concept. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 9 / 18

12 The Design Process Detailed Design Issues to be determined in the detailed design: Developing product layout and configuration Selecting materials for each component Addressing design-for-x issues (e.g. design for reliability, manufacturing, assembly, variation, costing, recycling) Optimizing the final geometry, including appropriate tolerances Developing completed digital models of all components and assemblies Simulating the system using digital and mathematical models Prototyping and testing critical components and modules Developing the production plans Simplicity The simpler design concept is better than a complex one, because fewer things can go wrong. Iteration Iteration is the process of making repeated changes and modifications to a design to improve and perfect it. Usability The usability of a product can become particularly problematic as its technology becomes more sophisticated. No matter how impressive the technology may be, if it is difficult to operate, customers will not embrace it as enthusiastically as they may have otherwise. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 10 / 18

13 The Design Process Detailed Design Documentation Engineers must be very diligent in documenting the design process s engineering drawings, meeting minutes, and written reports so that others can understand the reasons behind each of the decisions. Patents Patents are a key aspect of the business side of engineering because they provide legal protection for the inventors of new technology. Patents are one aspect of intellectual property, and they are a right to property, analogous to the deed for a building or a parcel of land. Rapid prototyping Sometimes engineers want a quick prototype to finalize some product features. A physical prototype is often useful for engineers to visualize complex machine components. Rapid prototyping has the capability to fabricate complex 3-D objects directly from a computer-generated drawing, often in a matter of hours. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 11 / 18

14 The Design Process Production Product being designed had better be something that actually can be built, preferably at a low cost. In the end, the design s function, shape, materials, cost, manner of production are tightly interconnected and balanced throughout the design process. That is why even at the requirements development stage, engineers must take into account requirements of manufacturing processes for the production stage. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 12 / 18

15 Manufacturing Processes Casting The main classes of manufacturing processes are as follows: Casting is the process whereby liquid metal, such as gray iron, aluminum, or bronze, is poured into a mold, cooled, and solidified. Figure 4: Examples of hardware produced by casting. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 13 / 18

16 Manufacturing Processes Forming The main classes of manufacturing processes (continued): Forming encompasses a family of techniques rolling, forging, extrusion whereby a raw material is shaped by stretching, bending, or compression. Large forces are applied to plastically deform a material into its new permanent shape. Figure 5: Examples of hardware produced by forging. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 14 / 18

17 Manufacturing Processes Machining The main classes of manufacturing processes (continued): Machining The most common machining methods (each uses a special sharp metal tool) are drilling (drill press) sawing (band saw) milling (milling machine) turning (lathe machine) (a) (b) Figure 6: (a) Drill press. (b) Milling machine. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 15 / 18

18 Manufacturing Processes Joining The main classes of manufacturing processes (continued): Joining operations are used to assemble subcomponents into a final product by welding, soldering, riveting, bolting, or adhesively bonding them. Many bicycle frames, for instance, are welded together from individual pieces of metal tubing. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 16 / 18

19 Manufacturing Processes Finishing The main classes of manufacturing processes (continued): Finishing steps are taken to treat a component s surface to make it harder, improve its appearance, or protect it from the environment. Some processes include polishing, electroplating, anodizing, and painting. abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 17 / 18

20 Bibliography 1 JONATHAN WICKERT & KEMPER LEWIS (2013): An Introduction to Mechanical Engineering, 3ed, Cengage Learning (ISBN-13: ) 2 SAEED MOAVENI (2011): Engineering Fundamentals: An Introduction to Engineering, Cengage Learning (ISBN-13: ) 3 PHILIP KOSKY, GEORGE WISE, ROBERT BALMER & WILLIAM KEAT (2010): Exploring Engineering An Introduction to Engineering and Design, Elsevier (ISBN ) 4 PHILIP KOSKY, GEORGE WISE, ROBERT BALMER & WILLIAM KEAT (2010): Exploring Engineering: An Introduction to Engineering and Design, Elsevier (ISBN ) 5 RAJENDER SINGH (2006): Introduction to Basic Manufacturing Processes and Workshop Technology, New Age International (ISBN-13: ) abu.hasan.abdullah c b n a 2017 SKMM 1922 Intro to MechE Mechanical Design 18 / 18

21 ... must end... and I end my presentation with two supplications my Lord! increase me in knowledge (TAA-HAA (20):114) O Allah! We ask You for knowledge that is of benefit (IBN MAJAH)