Design and Manufacturing Notes

8/8/2019 Design and Manufacturing Notes

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Design and Manufacturing NotesChapter 1

DEFINITION OF ENGINEERING DESIGN

1.1 Introduction:

The economic future of India depends on our ability to design, make and sell competitiveproducts. Excellent design and effective manufacture are the pre-requisites of a successiveindustry.

There is a general impression that the quality of Indian products can still be improved. Thefact that consumers have lost their confidence on Indian-made products cannot be denied.

This problem can be solved only by designing and manufacturing better products through

improved methodology. Keeping this in view, the subject Design and manufacturingpurpose to present the methods and procedures of design and manufacture.

Although engineers are not the only people who design things, the professional practice ofengineering is largely concerned with design. It is usually said that design is the essence ofengineering.

The ability to design is both a science and an art. The science can be learned throughprocedures developed by eminent scholars. But the art can be learned only by doingdesign.

1.2Types of Products A product is the tangible end result of a manufacturing process andis meant for satisfying human needs.

The product can be classified as follows: -

1.Convenience goodsThese are less expensive and are clustered around shops and restaurants. These can bepurchased at consumers convenience. E.g. Cigarette, Candy, Magazines etc.

2. Shopping goodsThese are expensive and people buy it less frequently. E.g. Jewellary garments etc.

3. Specialty goodsThese are purchased, taking extra pain. E.g. Rare objects like stamps.

4. Industrial goods.


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These are items used in the production of other items. Eg. Raw materials.

Another way of classifying products is into, (a) Continuous Products, and (b) Discreteproducts

The continuous products are those which are produced in a continuous fashion. Forexample, plates, sheets, tubes and bars etc are produced in very long lengths, and thenthese are cut into desired lengths.

On the other hand, discrete products are produced one after another, each in separateunits. On the basis of the output product, the Industry is usually named as continuousindustry and discrete industry.

1.3 Requirements in a good product1. Customer Satisfaction 2. Profit

How to achieve customer satisfaction?-

The product should function properly.-It must have desired accuracy-It must have desired reliability-It must be easy to operate-It must be serviceable-It must make minimum space utilization-It must withstand rough handling-Pleasant appearances.-Reasonable price.

How can it be profitable?-It must be easy to manufacture-The raw material must be cheap and easily available-The manufacturing process has to the decided on the basis of quantity to be produced-It must use standard parts-It must be easy to pack and distribute.

1.4 Definition of Design: (S 94)

Designing is such a vast field that it is defined in several ways.Various definitions of designing as pronounced by well-known designers are --:

Design is that which defines solutions to problem which have previously beensolved in a different way

Design is the conscious human process of planning physical things that display a


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new form in response to some pre-determined need.

Design is an act of collecting all pertinent information for the production of goodsand services to meet some human need.

The design of any component includes two things, (i) Product design (ii) Process designThe product design involves the development of specification for a product that will befunctionally sound, good in appearance, and will give satisfactory performance for anadequate life. The process design involves developing methods of manufacture of theproducts so that the component can be produced at a reasonably low cost.

1.5 History of Design Process

(i) Design by Single Person(ii) Over-the-wall design

(iii) Simultaneous Engineering(iv) Concurrent Engineering(v) Integrated design and Manufacture. In olden times one person could design andmanufacture an entire product.

Even for a large project such as the design of a ship or a bridge, one person had sufficientknowledge of the Physics, Materials and manufacturing processes to manage all aspects ofthe design and construction of the project. This period is referred to as the period of designby single person in the history of design.

Customers.

Marketing

Engg.

Design

Production

By the middle of the 20th century products and manufacturing processes became socomplex that, one person could not handle all aspects of design and manufacturing. Thissituation led to over-the-wall design process. In this method each functional departmentswere separated from others, as shown by wall. There was only one-way communicationsbetween Customer, Marketing, Engg. Design and production department.

The customers throw their needs to marketing department. The marketing department may


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throw the customer needs to the design department, in many instances, orally. The Engg.Design department may conceive a design and hands it over to the manufacturing sections.The manufacturing department interprets that design and makes the product according towhat they think suitable. Unfortunately, often what is manufactured by a company usingover-the-wall process is not what the customers had in mind.

his is due to lack of interaction between the different departments. Thus, this single directionover-the-wall approach is inefficient and costly and may result in poor quality products. Bythe early 1980s the concept of simultaneous engineering emerged. This philosophyemphasized simultaneous development of the manufacturing process- the goal was thesimultaneous development of the product and the manufacturing process. This wasaccomplished by assigning manufacturing representatives to be members of design team,so that they could interact with the design engineers throughout the designs process. In the1980s the simultaneous design philosophy was broadened and called concurrentengineering.

A short definition of concurrent engineering is the simultaneous progression of all aspects,

at all stages of product development, product specification, design, process and equipmentetc. In concurrent engineering the primary focus is on the integration of teams of peoplehaving a stake in the product, design tools, and techniques and information about theproduct and the processes used to develop and manufacture it. Tools and techniquesconnect the teams with the information. Although many of the tools are computer-based,much design work is still done with pencil and paper. In fact, concurrent engineering is 80%company culture and 20% computer support. With the advent of computer technology,drastic changes have taken place in the field of design and manufacturing.

The result was a completely integrated design and manufacturing system. This systemmakes a good use of technologies such as CAD/CAM, FMS etc. The computer integratedmanufacturing systems (CIMS) moves towards the Factory of the future. CIMS isnecessary for better quality, efficiency and productivity.

QUESTIONS1. How can you explain the term design? Explain the process of mechanical design.Discuss the role of creativity in the design process (S94, 8M) 2. The design of product is..........customer expectations. (S99, S94)3. .get first preference in designAnswer---. Functional requirements (S93)4. Explain the meaning of (i) Conceptual design (ii) Functional design (iii) Production design.Give suitable examples for each. (S03)

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CHAPTER 2

TYPES OF DESIGNS

2.1 The design can be classified in many ways. On the basis of knowledge, skill andcreativity required in the designing process.


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The designs are broadly classified into three types

(i) Adaptive Design (W 95, 97, 98 00)(ii) Variant Design (S 97, 99)(iii) Original Design

(i) Adaptive DesignIn most design situations the designers job is to make a slight modification of the existingdesign. These are calledadaptive designs. This type of design needs no special knowledgeor skill. E.g. converting mechanical watches into a new shape.

(ii) Variant DesignThis type of design demands considerable scientific training and design ability, in order tomodify the existing designs into a new idea, by adopting a new material or a differentmethod of manufacture. In this case, though the designer starts from the existing designs,the final product may be entirely different from the original product. E.g. convertingmechanical watches into quartz watches. Here a new technology is adopted.

(iii) Original DesignHere the designer designs something that did not exist previously. Thus, it is also callednew design or innovative design. For making original designs, a lot of research work,knowledge and creativity are essential. A company thinks of new design when there is anew technology available or when there is enough market push. Since this type of designdemands maximum creativity from the part of the designer, these are also called creativedesigns.

2.2 On the basis of the nature ofdesign problem, design may be classified as:(a) Selection design(b) Configuration design(c) Parametric design(d) Original design(e) Re-design

(a) Selection Design. It involves choosing one or more items from a list of similar items.We do this by using catalogues. Eg. -Selection of a bearing from a bearing catalogue-Selection of a fan for cooling equipment -Selecting a shaft.

(b) Configuration / Layout / Packaging Design (W 97, S'02)

In this type of problem, all the components have been designed and the problem is how toassemble them into the completed product. This type of design is similar to arrangingfurniture in a living room. Consider the packing of electronic components in a laptopcomputer. A laptop computer has a keyboard, power supply, a main circuit board, a harddisk drive, a floppy disk drive and room for two extension boards. Each component is ofknown design and has certain constraints on its position. For example, the extension slotsmust be adjacent to the main circuit board and the keyboard must be in front of themachine.


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Keyboard

Main Circuit board

Extension slots

Floppy drive

Power supply

The different components are shown above. The designers aim is to find, how to fit all thecomponents in a case? Where do we put what? One method for solving such problems is to

select a component randomly from the list and position it in the case so that all theconstraints on that component are met.

Let's take keyboard first. It is placed in the front. Then we select and place a secondcomponent. This procedure is continued until we reach a conflict, or all the components arein the case. If a conflict arises, we back up and try again. Two potential configurations areshown above.

(c) Parametric DesignParametric design involves finding values for the features thatcharacterize the object being studied. Consider a simple example We want to design a

cylindrical storage tank that must hold 4 m3 of liquid. The volume is given by V = r2 lThetank is described by the parameters, radius 'r', and length l. Given V = 4 m3 = r2 lr2 l=1.273 We can see a number of values for the radius and length, that will satisfy thisequation. Each combination-values of r and lgives a possible solution for the designproblem.

(d) Original DesignAs described in an earlier section, an original design in thedevelopment of an assembly or component that did not exist before.

(e) RedesignThe redesign is a modification of an existing product to meet newrequirements. It is same as adaptive design. Most design problems solved in industry arefor the redesign of an existing product. Suppose a manufacturer of hydraulic cylindersmakes a product that is 0.25m long. If the customer needs a cylinder 0.3m long, themanufacturer might lengthen the outer cylinder and the piston rod to meet this specialneed.

2.3. On the basis of the objective or strategythe designs are of following main types.

A. Production DesignB. Functional DesignC. Optimum Design

A. Production DesignInproduction design, the designer designs something in such a waythat the cost of producing the product is minimum. That is, the first responsibility of the


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designer is reduction of production cost. Hence, a production designer is concerned with theease with which something can be produced, and that at a minimum cost.

B. Functional Design W93 In functional design, the aim is at designing a part or memberso as to meet the expected performance level. Functional design is a way of achievinggiven requirements.- but the same may the unproducible or costly to produce. A gooddesigner, then, has to consider the production aspects also. A product designed withoutkeeping all these aspects into account, wastes time, money and efforts.

C. Optimum Design [W 95] It is the best design for given objective function, under thespecified constraints.

2.4 On the basis of the field/ area or the domain of design, the following types areimportant.

1. Mechanical Design2. Machine Design3. System Design4. Assembly/sub-assembly design5. Computer aided design

1. Mechanical DesignIt means use of scientific principles, technical information andimagination in the design of a structure,or machine to perform prescribed functions withmaximum economy and efficiency.

2. Machine DesignIt is the process of achieving a plan for the construction of a machine.

3. System DesignSystem Design is an iterative decision making process to conceive andimplement optimum systems, to solve problems and needs of society.

4. Assembly/sub-assembly design [S 93] In the design of Assembly/sub-assembly themajor criterion is the fulfillment of functional requirements. The assembly has to bedesigned to meet broad technical parameters and purpose for which it was meant.

The characteristic features are: The total number of parts used in the design must beminimum. Sub-assemblies should be capable of being built separately in order to givemaximum manufacturing flexibility. Standard parts may be used. Flexible parts shouldbe avoided, as they are easily damaged during handling and assembly.

5. Computer aided design [CAD] It is a design methodology in which the designs take theadvantages of digital computer to draw concepts, analyze and evaluate data etc.Computers are largely used in a design office for simulation and prototype study. In moderndesign, computers have become an indispensable tool.

Other types of designs are Probabilistic DesignIndustrial Design


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Probabilistic Design [S 96] It is a design approach in which design decisions are madeusing statistical tools. Generally, the external load acting on a body, the properties ofmaterials etc are liable to vary. In probabilistic design, the designer takes into account thevariations of such parameters.

Industrial Design [W 93] It is the design made by considering aesthetes, ergonomics andproduction aspects.

Questions

1. What are the characteristics features of system design, assembly/sub-assembly designand component design? Explain briefly with the help of examples. [S'93, 5M] 2. Distinguishbetween functional design and industrial design. [W'93]3. Discuss the meanings of conceptual design, creative design, adoptive design and variant

design. [S'97]4. What are the three main types of design? Give a comparative analysis. [W'00, W '97]5. Explain the difference between creative design, adoptive design and variant design. [S'02W'98]6. Designing for function involves the use and knowledge of .. Ans. Eng.Sciences [W '94]7. Explain the meaning of (i) Conceptual design, (ii) Functional design and (iii) productiondesign. Give suitable example of each. [S0'3]8. Explain layout design. [S0'2]

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Chapter 3

DESIGN PROCESS AND ITS STRUCTURES

3.1. Introduction

Developing a manufacturable product is not an easy job. This chapter presents somemethods that help achieve quality products. Rather than making a detailed study, only anoverview of designing process is attempted here.

3.2. Features of design process

The following features can be observed in a design process.* Iteration* Decision-making* Conversion of resources* Satisfaction of need


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Design is completed in many phases. In each phase, repeated attempts are required toaccomplish the aim. A satisfactory conclusion can be reached on, only after a number oftrials. Decision-making is essential for a designer to select one out of several. A designeroften comes across several equally acceptable alternatives to meet some end. In suchconflicting situations, designer has to make the best decision. In any design process, thereis conversion of resources such as time, money, talent, materials and other naturalresources. All designs are aimed at satisfying some human need. Needs, whether importantor unimportant is the starting point of design.

3.3. How a design is born?

In a broad sense there are two methods by which a design comes into existence.a. Design by evolution (Traditional Design)b. Design by innovation (Modern Design)

a. Design by evolution

This implies the traditional method of design in which the objects and articles that we seearound has taken its present form by gradual change of time. If one looks at history it canbe seen that most of the tools, equipments, implements, took a long time to acquire theirpresent form. Things changed gradually with the passage of time. Each change was madeto rectify some defects or difficulties faced by the users. Bicycles, calculators, computers,steam locomotives etc. all went through a process of evolution in which designers tried oneconcept after another. Even today this process is being used to some extent. However, thisevolutionary process is very slow. i.e., it took a very long period of time to occur even a

slight modification.

he main reason for this slow evolutionary process of design was the absence of properinformation and design data records.

In modern design situations the evolutionary methods are not adequate because of thefollowing reasons.

1. The traditional designing did not consider the interdependence of products. They wereconcerned about only one component /product. But in the modern world, the existence ofone product is dependent on another in some way or other.

2. In the past, production was on small scale. Thus the penalty of a wrong design wastolerable. But, in the present time, production is on large-scale basis. As a result, anypenalty of a wrong design will cost great loss.

3. Requirements of the customers of todays world changes so frequently. Traditional


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design lags behind the advanced product & process technologies available today.

4. Traditional design methods cannot cope with competitive requirements of the modernworld. Due to the above reasons modern design problem cannot be handled by traditionalmethods.

b. Design by Innovation

Since the traditional design method failed to cope with modern design requirements,nowadays almost all designs are made by innovation. i.e., developments of a product byfollowing scientific and purposeful effort. The innovative design is entirely different from thepast practice of evolutionary design. Here the designers task is greatly magnified. He hasto design and create something, which did not exist yet. Here he tries to solve the designproblem in a systematic and orderly manner.

This approach is similar to analytical problem solving. However, an innovative designerfaces the following difficulties.

1. He has to collect and evaluate information on a product, which is non-existing yet.

2. Necessity of analyzing complicated interaction of components.

3. He has to make predictions regarding its performance.

4. He has to ensure the technical and economical feasibility of the product. Notwithstandingthe above difficulties, there are eminent experts like Morris Asimow, J.E. Shigly, Dieter etchave attempted to systematize the design process.

This systematized steps in design process is called Morphology of Design. The best way inwhich any problem can be solved is to break up the problem and to try for a solution in ananalytical method. This approach of problem solving is also adopted in the Morphology ofdesign.

3.4. Problem-solving Methodology

Knowingly or unknowingly we follow six basic actions when we try to find solution of anyproblem.

1. Establish or convince ourselves that there is a problem. Or we understand that asolution is needed.

2. Plan how to solve this problem


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3. By analyzingthe problem we decide what is actually requiredfrom the problem-solver. Orwe decide the requirements.

4. Generate alternative solutions.

5. Evaluate the alternatives.

6. Presentthe acceptable solution.

3.5. Morphology of Design.

Morphology means a study of form or structure. Morphology of design refers to the timebased sequencing of design operations. It is a methodology of design by which ideas aboutthings are converted into physical objects. The logical order of different activities or phasesin a design project is called the morphology of design.

3.6. Design Process- Simplified Approach

A simplified approach to designing as outlined by Morris Asimow is given below. Accordingto him the entire design process in its basic forms consists of five basic elements as givenbelow.

General Information

Specific Information

Design Operations

Outcome

Evaluation

No

Yes

GO TO NEXT STEP

Design operations imply the various processes done during designing. These include Searching for possible alternatives systems to satisfy a need. Formulating a model foranalysis purpose. Materials selection, etc. But in order to carryout the above processes(i.e., design operations) a lot of information is required.


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The required informations may be broadly classified into two.1. General InformationE.g. Scientific Laws Information on market trends etc.2. Specific information. E.g. Information on manufacturers catalogue Materials sciencehandbook etc. Once the designer has obtained the necessary information he can startdesign operations.

The design operations give outcomes. The outcome may be in the form of Computer printouts, or drawings. Next stage is the evaluation of this outcome. The purpose of evaluation isto decide whether this outcome is able to meet the need. Here a comparison between thecapabilities of the outcome and the need is carried out. If the outcome is sufficient to meetthe need, the designer goes on to next step, otherwise the design operation is repeated.

3.7 Detailed Morphology of DesignA design project goes through a number of time phases. Morphology of design refers to thecollection of these time phases. The morphology of design as put forward by Morris Asimowcan be elaborated as given below.

It consists of seven phases.:

I. Feasibility study

II. Preliminary Design

III. Detail design

IV. Planning for manufacture

V. Planning for distribution

VI. Planning for use

VII. Planning for retirement

Phase 1. Feasibility Study.This stage is also called conceptual design. A design project always begins with a feasibilitystudy. The purpose and activities during feasibility study are To ascertain there reallyexists a need [ie the existence of need must be supported by necessary evidences, rather

than the outcome of ones fancy] Search for a number of possible solutions Evaluate thesolutions i.e. is it physically realisable? Is it economically worthwhile? Is it within ourfinancial capacity? Phase

2 Preliminary (Embodiment) Design.This is the stage art which the concept generated in the feasibility study is carefullydeveloped. The important activities done at this stage are: * Model building & testing * Study


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the advantages and disadvantages of different solutions. * Check for performance, qualitystrength, aesthetics etc.

Phase III: Detail Design

Its purpose is to furnish the complete engineering description of the tested product. Thearrangement, from, dimensions, tolerances and surface properties of all individual parts aredetermined. Also, the materials to be used and the manufacturing process to be adoptedetc. are decided. Finally, complete prototype is tested.

Phase IV: Planning for manufactureThis phase includes all the production planning and control activities necessary for themanufacture of the product.

The main tasks at this phase are

* Preparation of process sheet, i.e. the document containing a sequential list of

manufacturing processes.* Specify the condition of row materials.* Specify tools & machine requirements.* Estimation of production cost.* Specify the requirement in the plant.* Planning QC systems.* Planning for production control.* Planning for information flow system etc.

Phase V: Planning for Distribution

The economic success of a design depends on the skill exercised in marketing. Hence, thisphase aims at planning an effective distribution system.

Different activities of this phase are* Designing the packing of the product.* Planning effective and economic warehousing systems.* Planning advertisement techniques* Designing the product for effective distribution in the prevailing conditions.

Phase VI Planning for Consumption/useThe purpose of this phase is to incorporate in the design all necessary user- orientedfeatures.

The various steps are* Design for maintenance* Design for reliability* Design for convenience in use* Design for aesthetic features


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* Design for prolonged life* Design for product improvement on the basis of service data.

Phase VII: Planning for Retirement.

This is the phase that takes into account when the product has reached the end of usefullife.

A product may retire when* It does not function properly* Another competitive design emerges* Changes of taste or fashion The various steps in this phase are* Design for several levels of use* Design to reduce the rate of obsolescence.* Examine service-terminated products to obtain useful information.

3.8. Methods of Innovative Design

As we know, innovative design is an organized, systematized and logical approach forsolving a design problem.

There are two design methods for innovative design.(i) Design by creative design route(ii) Engineering Design

(i) Design by creative routs [Creative Design]

This is a design method that demands maximum creativity from the part of the designer.Hence this method is also called creative design. Here the designer finds solutions toproblems by allowing his creativity aspects grow in a particular manner. Creativity [S94,W95, W98, S03]

Majority of designs belong to variant design, where the designer simply modifies an existingsystem. But the success of engineering design depends on the modes of thinking andacting distinctively different from others. A creative designer is distinguished by his ability tosynthesize new combinations of ideas and concepts into meaningful and useful forms.Design is commonly thought of as a creative process involving the use of imagination andlateral thinking to create new and different products.

Qualities of a creative designer[S96, S00, S03]

The creative designer is generally a person of average intelligence, a visualiser, a hardworker and a constructive non-conformist with average knowledge about the problem at


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hand.

Generally, a creative designer has the following qualities.* Visualization ability. Creative designers have good ability to visualize, to generate andmanipulate visual images in their heads.

* Knowledge All designers start their job with what they know. During designing, they makeminor modifications of what they already know or, creative designers create new ideas outof bits of old designs they had seen in the past. Hence, they must have knowledge of pastdesigns.

* Ability to manipulate knowledge The ability to use the same knowledge in a different wayis also an important quality of a designer.

* Risk taking A person who does not take the risk of making mistakes cannot become agood designer. For example, Edison tried hundreds of different light bulb designs before hefound the carbon filament.

* Non-conformist There are two types of non-conformists:-constructive and obstructive.Constructive non-conformists are those who take a firm stand, because they think they areright. Obstructive non-conformists are those who take a stand just to have an opposingview. The constructive non-conformists might generate a good idea. But the obstructivenon-conformists will only slow down the design process. Creative designers areconstructive non-conformists, and they want to do things in their own way.

* Technique Creative designers have more than one approach to problem solving. They areprepared to try alternative techniques, till they reach a satisfactory solution.

* Motivation They always motivate others in the design team. In such a favourableenvironment creativity is further enhanced.

* Willingness to practice Creativity comes with practice. Creative designers are ready topractice for a long enough period.

Roadblocks to Creativity

* Fear of making a mistake

* Unwillingness to think and act in a way other than the accepted norm.

* Desire to conform to standard solutions.

* Unwillingness to try new approaches

* Fear of criticism


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* Lack of knowledge

* Overconfidence due to past experience

* Unwillingness to reject old solutions

* Fear of authority

* Difficulty in visualization

* Inability to distinguish between cause and effect

* Inability to collect complete information

* Unwillingness to be different

Methods to enhance Creativity

* Use of analogy

* Asking question from different view points

* Memories of past designs

* Competitive products

* Deliberate day-dreaming

* Reading science fictions, etc.

Intuition [S01]Intuition means sudden ideas or flashes of inspiration and involves complex associations ofideas, elaborated in subconscious mind. Intuitive ideas lead to a large number of good andeven excellent solutions.

Creative Design Route [W95, 94, 98, 900]

Creative design route is the procedure through which a creative design is born. Thesuccess of this design lies with the creativity of the designer. Creative design route can bepracticed by following the sequences shown in figure.

During preparation period, the designer analyses the need and collect all the necessaryinformation required at various stages.


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Preparation

Concentration

Incubation

Illumination

Verification

Concentration is the period when the designer digests all the aspects of the problemsituation and tries various possible combinations. The next step is the incubation period.The designer relaxes away from the problem for some time. Illumination is the suddeninsight and throwing up with a solution. The final step is the verification. Now, testing andinspection of the design is done and the details are completed. For a designer usingcreative methods for design, habitual or familiar methods must be avoided.

(ii) ENGINEERING DESIGN (W 96)

Another procedure for obtaining innovative design is Engg. Design.

Apart from creativity-approach, this is a logical and intellectual attempt to solve designproblems. It largely depends on discoveries and laws of science.

The different steps in Engg. design process is given below:

- Recognition of need-Definition of the problem-Gathering of Information-ConceptualizationEvaluation of concepts

Communication of the design

Since all design projects are meant for satisfying some need, any design work startswith Recognition of the need.


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The need for a design is initiated by either a market requirement, the development of a newtechnology or the desire to improve an existing product.

Once the need has identified, the next step is to define the design problem. This is the mostcritical step in the design process.

The definition of the problem expresses as specifically as possible, what the design isintended to accomplish. It should include objectives and goals, definitions of any specialtechnical terms, the constraints on the design and the criteria that will be used to evaluatethe designs.

The success of a design project depends on the clarity in the definition of the problem.Need Analysis is the technique used to define the problem(Chapter 6). The next stepis collecting information. In many phases of deign process a large quantity of information

may be required. The required information can be obtained from textbooks, journals, orother agencies (See Art. 6.4) The conceptualization step involves, finding several designideas to meet the given need. Inventiveness and creating is very important in this step. Thedifferent ideas conceived are weighted and judged in theevaluation step. The advantagesand disadvantages of each idea against its performance, cost aesthetics etc is valued. Afterevaluation, the best design is emerged. This final design with every detail is furnished in laststep-ie communicatingthe design.

Common features between Creative Design & Engg. Design (W.94)

(1) The preparation phase in creative design and need analysis in Engg. Design is more orless common. Both steps deal with analyzing the need.

(2) In both design methods brainstorming and Synetics can be applied.

(3) Reviewing is applicable in both design methods.

(4) For both deigns, the success depends on the clarity with which the need statement isprepared.

(5) Testing and inspection is applicable for both designs.

Difference between Creative Designs & Engg, Designs (W 94)

1. Intelligence is not a must for creative design-but the same is desirable in Engg. Design.


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2. Creative design is based on use of analogy and synthesis of alternatives butengineering design is based on proven laws and past experience.

3. Creative design involves phases like incubation, illumination but no such philosophy isfollowed in engineering designs.

4. Creative person is highly intuitive and independent in thinking and usually resists workingin group but engineering designers like teamwork.

5. Customs, habits and traditions are enemies of creativity but the same are required inengineering design.

3.9. Divergence, Transformation & Convergence (S97 5M)The entire design process can be said to have composed of three distinct phases Viz.Divergence, Transformation and Convergence phases. The problem definition, need

analysis and conceptualization etc. aims at generating as many ideas as possible to solve agiven design problem. Thus, these activities belong to the Divergence phase. That activitywherein the concept is converted into physical object is termed as transformation phase.The convergence is a narrowing process, where the best optimal solution is tried for, byeliminating unwanted ideas.

3.10. Design Process Using Advanced Technology (W00)

Although Engineering is a major sector of the economy in a developing country. It has notbeen benefited greatly from advances in computer technology. Engineers still usecomputers only in peripheral tasks, such as drafting and analyzing, but not in making

fundamental design decisions.

Current computer tools such as computer-aided drafting are restricted to the end of thedesign process and play no fundamental role in aiding design. It aids only in the finaldrafting of the specifications. Computer-aided Design, (CAD) means a class of tools forcrating drawing, or the physical description of the object. CAD systems have beensophisticated and 2D and 3D models are available. The CAD allows the designer toconceptualize objects more easily.

The design process in CAD system consists of the following stages.

1) Geometric modeling

2) Analysis and optimization

3) Evaluation

4) Documentation and drafting.


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QUESTIONS

1. How can you explain the term design? Explain the process of mechanical design.Discuss the role of creativity in the designs process. (S94. 8M)

2. The mechanical design process normally has six stages and amongst them the threestage are ----- ------ ------- (S99, S94, 1 M)

3. What is morphology of design? Explain the various steps with the help of block diagram(W.95)

4. The three stages of design are (W 96)

5. State the different phases that are involved in morphology of design (S.96)

6. Briefly discuss the concept of creativity as applicable for solving design problems (W 98.

6M)

7. What makes the design process tortuous? Explain (W 99, 6M)

8. The creative design process can be considered to be (S93)

9. Discuss creativity and creative design. Use examples to explain. (W 95)

10. What do you understand by intuition (S 01)

11. Draw a flow-chart showing different stages of engineering design. Explain why some

stages are repeated several times. (S.93.5M)

12. What feedback loops provide information for the redesign of products and theproductive systems. (W93)

13. The process of design by evolution adopted by craftsman is a .. Ans. Slowprocess of design development (W94)

14. With suitable examples, compare Design by evolution and Design by innovation. (S96)

5. Enumerate the steps in Engg. Design process and explain (W96)

16. Justify the statement with reasons Modern design problems cannot be handled bytraditional methods. (S97, W98)

17. Good design requires both------ --------. Ans. Analysis and Synthesis. (S93)

18. Define creative design routes. What are the stages of these routes, Explain these inbrief. (S00)


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19. Explain the process involved in creativity. What are the various qualities of creativedesigner? Give the brief description of these. (S00).

20. What do you mean by creative design routes. Write down the different statements aboutcreativity and creative designers. (S01)

21. Compare the design synthesis and design analysis. Explain the basics procedure ofdesign synthesis giving suitable examples. (S 02).

22. What are the common features and differences between creative design activities andEngg? Design activities. Explain briefly with the help of examples. (W94)

23. Discuss the divergence, transformation, and convergence phases in the design of a newproduct. (S97)

24. What are the three different stages in the design process? Explain with example.

(W99)

25. What are the most important steps involved in the design process? Explain? (W00)

26. What are the methods currently being adopted for design process using advancedtechnology? (W00)

27. Name various phases in design morphology. Explain these in brief. (S01)

28. Explain Engg. Design (S01)

29. What major steps are involved in design process? Briefly explain each one (W01).

30. What do you understand by the design process? List out the various phases involvedand explain them briefly. (S02)

31. Give the checklist for an engg. Design problem. (W98)

32. ___ is one of the most powerful aids to creativity in design.(Use of analogy) (W 94).

33. What do you understand by the term creativity? What are its requirements? (03).

34. Discuss the stages in engineering design process with the help of example. (S 05)

35. Explain Design processes. Illustrate the steps followed with the help of a figure.

Also explain the flow of work during the designprocess. (W 05, 8M)36. What do youunderstand by morphology of design? Discuss the phases of feasibility study,

preliminary design and detailed design. (W 05. 8M)


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CHAPTER 4

IDENTIFICATION OF NEED4.1. What is a need?

A need can be defined as a personnel unfulfilled vacancy which determines and organizesall psychological and behavioral activities in the direction of fulfilling the vacancy A productcan be product and marketed only if it is needed by the customer. A person buys a penbecause he needs to write. A patient needs something that can cure his illness.

These examples show that needs are nothing but a scarcity or problem or wants felt by aperson, device or a system. In fact a designers goal is to find solutions to such problems

4.2. Hierarchy of Human needs (W 96)

Maslow developed a hierarchy of human needs as given below

1. Physiological needs - These are the basic needs of the body- For example, thirst, hunger,sex, sleep etc.

2. Safety and security needs For a person whose physiological needs are met, the newemerging needs are safety needs. These include, protection against danger, threat etc.

3. Social needs Once the physiological and safety needs are met, the next dominant needis social need. For example he/she want to love and be loved, he want to be in group, etc.

4. Psychological needs These are the needs for self-respect and self- esteem, and forrecognition.

5. Self-fulfillment needs These are the needs for the realisation of ones full potentialthrough self-development, creativity, and self-expression.

4.3. Identification/Recognition of Needs (W 96)

The beginning of any design process is the recognition of need or problem. When a turnerhears an awkward noise from some part of the lathe he identifies/ recognises a need. i.e.

the lathe requires repair. When the sales personnel observes that their customers arealways complaining of poor performance of the products, a need to develop a better productis identified.

Similarly, when the customers are unsatisfied with the present model, a new need isrecognised.

Needs can be identified from,


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* Careful market analysis* Statements made by politicians from their observations* Interpretations of a communitys requirements* Trends in other parts of the world

4.4. Variety of Needs [S00]Following are the needs, which can generate ideas for the development of new products.

(i). Variation of an existing product. This could be a change in a single or a fewparameters of an existing product. Eg - Changing the length of a cylinder. -Changing thepower of a motor, etc.

(ii) Improvements in the existing product. This implies the need to redesign some of thefeatures of an existing product. Such needs can arise, when -Customers want a new featureor better performance than existing features -A vendor can no longer supply components ormaterials that had been used so far -Manufacturing or assembly departments identifies a

quality improvement -Invention of a new technology that can be incorporated in the existingdesign.

(iii) A change in production model Whenever the production model changes from job-shopto mass, a corresponding change in product design may be demanded. For example, thereis more tendency to buy off-the shelf components for short-run products. Whatever may bethe situation, a company has to identify or locate a need before the production of anydevice.

This crucial step is called Recognition/ Identification of need.

Examples:1. With the free-entry of Chinese products to Indian market, manufacturers in Indiarecognize a need to sell their products at a lower price.2. When a company observes that their products do not perform well, the companyrecognizes a need to re-design it.

4.5 Need StatementOnce the need has recognized, the next step is to prepare the need statement. It is ageneral statement specifying the problem for which a solution is required. In other words-Itis the objective of design, expressed in the form of a statement.

Need Statement Examples [S 93]

Give one need statement for each of the followingBicycleVoltage stabilizersPersonnel Computer

i). Bicycle: - The need statement for a bicycle could be A device for a common person to


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travel reasonable distance comfortably with least effort The initial cost should be low- andbe as light as possible, have adequate life, be easy to maintain etc

(ii). Voltage stabilizerA solid state noiseless electrical device of adequate power rating toprovide continuously an output at constant voltage, accepting the input power at varyingvoltage between the limits__and__volts . The indications for input and output voltage levelsmay be provided.

iii). Personnel ComputerA computing device to accept input data, manipulate it accordingto a set of instructions and provide the desired output on CRT and printer

Questions

1. List hierarchy of human needs that motivate individuals. [W96]2. Give one need statement for each of the following Bicycle (ii) Voltage stabilizer (iii)Personnel Computer [S93]

3. Explain the steps involved in identification of a problem by a designer [S96]4. Every product is made in response to.of individual or society. Ans. needs [S97]5. Enumerate and explain variety of needs which can generate ideas for the Developmentof new product. [S00]

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CHAPTER 5

PRODUCT PLANNING

5.1 IntroductionOnce the top management of an organisation recognized a need to develop a product, it willgo for product design, only if, - the purposed product will guarantee a handsome profit - themarket conditions are favorable in respect of competition. - the necessary resources areavailable - the purposed design is worthwhile.

5.2 Feasibility Study.The starting point of a design project is a need. Once the need has been identified, thecompany has to ensure the worth of the project. Feasibility study is a preliminary analysisfor making a decision regarding the design project, to be forwarded or not. If the feasibilitystudy reveals that the proposed design project does not bring comfortable revenue, or thedesign demands huge investments beyond the capacity of the organisation, the project isdropped.


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5.3 .Product Planning [S 01]

Planning is the process used to develop a scheme for scheduling and committing theresources of time, money and people. A plan shows how a project will be initiated,organized, co-coordinated and monitored.

A product plan is a decision-making as regards to the design and manufacture of a product,by considering the revenues from different products.

For example assume that a company already manufacturing 3 products, say P1, P2 and P3identifies a need to design a new product N. Owing to the design and manufacture of thenew product, the production volume, and hence revenue from products P1, P2,and P3 maybe affected (due to re-allocation of company resources such as raw materials,machineries).

In this situation, the company has to decide a time-schedule for the design and manufactureof the new product. Such plan made by the management is called the product plan. It must

contain the time-as well as resource allocation for each of the products. More over it willresult in optimum and efficient use of resources. After the product plan in made, themanagement begins a project for a new product design.

5.4. Organisation Of Design Group

The complexity of mechanical devices has grown rapidly over the last 200 years. Forexample Boeing 747 aircraft (which has over 50,000 components) required over 10thousand persons years of design time. Thousands of designers worked over a three-yearperiod on the project. These show that, design work is generally done by a team or group. A

design team may include thousands of design and manufacturing engineers, materialscientists, technicians, purchasing agents, drafters, and quality control specialists, allworking over many years. The first phase in any design process is identification of needs.Needs may be identified by market survey, the desire to improve an existing product oreven by the development of a technology. Since any design activity consumes companyresources like money, people and equipments etc. the planning of these resources is thenext phase after need- identification. Planning means allocation of resources such asmoney, people etc. The first step in planning is to form a design team.

5.5. Members of Design Team

Following is a list of individuals needed in a design team.Their titles may vary from company to company.

1. Design Engineer. This person is responsible for suggesting ideas for the proposedproduct. For that, he must clearly understand needs for the product as well as itsengineering requirements. Hence, he must posses both creative and analytical skills. Hemust be an engineering graduate having vast experience in the particular product area.


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2. Marketing Manager. He is responsible for success of the product in the market. He is alink between the product and the customer. He always sees whether the customer like thisproduct?

3. Manufacturing Engineer. He knows the best manufacturing process suitable for theproduction of the particular product. He can give advice on the various manufacturingprocesses available in the industry.

4. DetailerIn many companies the design engineer is responsible for specificationdevelopment, planning, conceptual design and the early stages of product design. Theproject is then turned over to detailers who finishes the details, develops manufacturing andassembly documents.

5. DrafterA drafter aids the design engineer and detailer by making drawing of the product.In many companies the detailer and the drafter are the same individual.

6. Technician. The technicians aid the design engineer in developing test-apparatus,

performing experiments etc.

7. Materials Specialist. In some products, the choice of the material is based onavailability. In some other cases, a certain material is to be chosen according to somefeatures of the product. Material specialist can give advice on properties of differentmaterials.

8. Quality Control Specialist. A quality control specialist observes how well the productmeets specifications. This inspection is done on finished products as well as raw materialspurchased from vendors.

9. Industrial Engineer. Industrial designers are responsible for how a product looks andhow well it interacts with customers. They generally have background in fine arts and inhuman factor analysis.

10. Assembly Manager. The assembly manager is responsible for putting the producttogether. Note that assembly process is an important aspect of product design.

11. Suppliers Representative. As part of product development, the company maypurchase components or sub-assemblies from out-sources. In that case, the representativeof the supplier of the specified component must be included in the design team.

5.6 Organisational Structure of Design Teams

Since a design project requires individuals with different fields of expertise, they can beorganised into different structures. Listed below are the five organisational structures.The number in the bracket shows the percentage of design projects that use that particularorganisation structure.

1. Project matrix, (28%) It is an organisation structure having the features of project andmatrix organisations.


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2. Functional matrix (26%) It is another organisational structure obtained by combiningfunctional as well as matrix organisations.

3. Balanced Matrix (16%) Here the project manager and functional manager work together.A project manager is assigned to oversee the project, and the responsibility and authorityfor completing the project rests with functional managers.

4. Project Team (16%) A project manager is put in charge of a project team composed of acore group of personnels from several functional areas or groups assigned on a full timebasis.

5. Functional Organisation (13%) Each project is assigned to a relevant functional area orgroup within a functional area. A functional area focuses on a single discipline.

5.7. Task Clarification [S 01]

A project plan is a document that defines the tasks necessary to be completed during adesign process. A project plan is used to keep the project under control. It helps the designteam and management to know how the project is actually progressing.

There are five steps to establish a plan.

They are,1. Identify the task2. State the objective of each task

3. Estimate Personnels, time, resources required.4. Develop a sequence for these tasks.5. Estimate product development cost.

Step 1 Identify the tasks

In the first step of the planning of the design project, the different tasks needed to bring theproblem from its initial state to the final products are identified. The tasks are the activities to

be performed during the design process.

Given below is a list of tasks drafted by a design team, for the development of a certainproduct.

a. Collect and evaluate customer requirements and competition scenario.b. Establish two concepts for product development.c. Develop final prototype.d. Test prototype No1 and select one design for finalisation.


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e. Redesign and produce proto type No2.f. Field test prototype No2.g. Complete production documentation.h. Develop marketing plan.i. Develop quality control procedures.

j. Prepare patent applications.k. Establish product appearance.l. Develop packaging.

Step .2. State the objective for each task.

Even though the tasks are initially identified, they need to be refined to ensure that theresults of the activities are the stated objectives.For example, for the task No.(a) above, the objective is to collect information required for developing specification.

Step 3: Estimate the Personnel, Time & other Resources Required.

Completion of each of the tasks listed above will consume resources such as personnel,time etc. An estimate of the requirement of resources may looklike: Task Personnel/time Collecting data Two market surveyors, two months Conceptgeneration Two designers, two week.

Step 4 Develop a Sequence for the tasksThe next step is scheduling of tasks-the purpose is to ensure that each task is completed,before its result is needed. CPM is the best method to accomplish this.Step 5 Estimate Product Development Cost

On the basis of the above steps, the costs for developing the product can be estimated.Normally design cost is only about 5% of manufacturing cost. The above plan developed inthe early stage of the design has to be refined as the project progresses.

Questions

1. Market research is necessary before starting the production of any product. (True) [S '97]2. Write a short note on Product planning and task classification. [S '01]

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