Wednesday, May 13, 2009

Chapter 3 : DESIGN PROCESS AND ITS STRUCTURES

3.1. Introduction
Developing a manufacturable product is not an easy job। This chapter presents some methods that help achieve quality products. Rather than making a detailed study, only an overview 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
Design is completed in many phases. In each phase, repeated attempts are required to accomplish the aim. A satisfactory conclusion can be reached on, only after a number of trials.
Decision-making is essential for a designer to select one out of several. A designer often comes across several equally acceptable alternatives to meet some end. In such conflicting situations, designer has to make the best decision.
In any design process, there is conversion of resources such as time, money, talent, materials and other natural resources.
All designs are aimed at satisfying some human need। Needs, whether important or 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 see around has taken its present form by gradual change of time. If one looks at history it can be seen that most of the tools, equipments, implements, took a long time to acquire their present form. Things changed gradually with the passage of time. Each change was made to 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 one concept after another. Even today this process is being used to some extent. However, this evolutionary process is very slow. i.e., it took a very long period of time to occur even a slight modification. The main reason for this slow evolutionary process of design was the absence of proper information and design data records.
In modern design situations the evolutionary methods are not adequate because of the following reasons.
1। The traditional designing did not consider the interdependence of products. They were concerned about only one component /product. But in the modern world, the existence of one 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 was tolerable. But, in the present time, production is on large-scale basis. As a result, any penalty of a wrong design will cost great loss.

3। Requirements of the customers of today’s world changes so frequently. Traditional design lags behind the advanced product & process technologies available today.

4 Traditional design methods cannot cope with competitive requirements of the modern world.
Due to the above reasons modern design problem cannot be handled by traditional methods.
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 by following scientific and purposeful effort.
The innovative design is entirely different from the past practice of evolutionary design। Here the designer’s task is greatly magnified. He has to design and create something, which did not exist yet. Here he tries to solve the design problem in a systematic and orderly manner. This approach is similar to analytical problem solving.

However, an innovative designer faces 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.

Notwithstanding the above difficulties, there are eminent experts like Morris Asimow, J।E. Shigly, Dieter etc have attempted to systematize the design process. This systematized steps in design process is called Morphology of Design. The best way in which any problem can be solved is to break up the problem and to try for a solution in an analytical method. This approach of problem solving is also adopted in the Morphology of design.

3.4. Problem-solving Methodology
Knowingly or unknowingly we follow six basic actions when we try to find solution of any problem।

1. Establish or convince ourselves that there ‘is’ a problem. Or we understand that a solution is needed.
2. Plan how to solve this problem
3. By analyzing the problem we decide what is actually required from the problem-solver. Or we decide the requirements.
4. Generate alternative solutions.
5. Evaluate the alternatives.
6। Present the acceptable solution.

3.5. Morphology of Design.
Morphology means ‘a study of form or structure’। Morphology of design refers to the time based sequencing of design operations. It is a methodology of design by which ideas about things are converted into physical objects. The logical order of different activities or phases in a design project is called the morphology of design.

3.6. Design Process- Simplified ApproachA simplified approach to designing as outlined by Morris Asimow is given below। According to him the entire design process in its basic forms consists of five basic elements as given below
3.7 Detailed Morphology of Design
A design project goes through a number of time phases. Morphology of design refers to the collection of these time phases. The morphology of design as put forward by Morris Asimow can be elaborated as given below. It consists of seven phases.
Phase 1. Feasibility Study.
This stage is also called conceptual design. A design project always begins with a feasibility study. The purpose and activities during feasibility study are
¬ To ascertain there really exists a need [ie the existence of need must be supported by necessary evidences, rather than the outcome of one’s fancy]
¬ Search for a number of possible solutions
¬ Evaluate the solutions
i.e. is it physically realisable?
Is it economically worthwhile?
Is it within our financial capacity?
Phase 2 Preliminary (Embodiment) Design.
This is the stage art which the concept generated in the feasibility study is carefully developed. The important activities done at this stage are:
* Model building & testing
* Study the advantages and disadvantages of different solutions.
* Check for performance, quality strength, aesthetics etc.

Phase III: Detail Design
Its purpose is to furnish the complete engineering description of the tested product. The arrangement, from, dimensions, tolerances and surface properties of all individual parts are determined. Also, the materials to be used and the manufacturing process to be adopted etc. are decided. Finally, complete prototype is tested.
Phase IV: Planning for manufacture
This phase includes all the production planning and control activities necessary for the manufacture 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, this phase 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/use
The purpose of this phase is to incorporate in the design all necessary user- oriented features. The various steps are
* Design for maintenance
* Design for reliability
* Design for convenience in use
* Design for aesthetic features
* 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 useful life. 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 for solving 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 to problems 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 existing system. But the success of engineering design depends on the modes of thinking and acting distinctively different from others. A creative designer is distinguished by his ability to synthesize 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 and lateral 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 hard worker and a constructive non-conformist with average knowledge about the problem at hand.
Generally, a creative designer has the following qualities.
* Visualization ability.
Creative designers have good ability to visualize, to generate and manipulate visual images in their heads.
* Knowledge
All designers start their job with what they know. During designing, they make minor modifications of what they already know –or, creative designers create new ideas out of bits of old designs they had seen in the past. Hence, they must have knowledge of past designs.
* Ability to manipulate knowledge
The ability to use the same knowledge in a different way is also an important quality of a designer.
* Risk taking
A person who does not take the risk of making mistakes cannot become a good designer. For example, Edison tried hundreds of different light bulb designs before he found 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 are right. Obstructive non-conformists are those who take a stand just to have an opposing view. The constructive non-conformists might generate a good idea. But the obstructive non-conformists will only slow down the design process. Creative designers are constructive non-conformists, and they want to do things in their own way.
* Technique
Creative designers have more than one approach to problem solving. They are prepared to try alternative techniques, till they reach a satisfactory solution.
* Motivation
They always motivate others in the design team. In such a favourable environment creativity is further enhanced.
* Willingness to practice
Creativity comes with practice. Creative designers are ready to practice 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
* 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 [S’01]
Intuition means sudden ideas or flashes of inspiration and involves complex associations of ideas, elaborated in subconscious mind. Intuitive ideas lead to a large number of good and even excellent solutions.
Creative Design Route [W95, 94, 98, 9’00]
Creative design route is the procedure through which a creative design is born. The success of this design lies with the creativity of the designer. Creative design route can be practiced by following the sequences shown in figure.
During preparation period, the designer analyses the need and collect all the necessary information required at various stages.

Concentration is the period when the designer digests all the aspects of the problem situation 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 sudden insight and throwing up with a solution.
The final step is the verification. Now, testing and inspection of the design is done and the details are completed.
For a designer using creative 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 design problems. It largely depends on discoveries and laws of science.
The different steps in Engg. design process is given below: -


Since all design projects are meant for satisfying some need, any design work starts with Recognition of the need. The need for a design is initiated by either a market requirement, the development of a new technology 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 most critical step in the design process. The definition of the problem expresses as specifically as possible, what the design is intended to accomplish. It should include objectives and goals, definitions of any special technical terms, the constraints on the design and the criteria that will be used to evaluate the 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 step is 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, or other agencies (See Art. 6.4)
The conceptualization step involves, finding several design ideas to meet the given need. Inventiveness and creating is very important in this step.
The different ideas conceived are weighted and judged in the evaluation step. The advantages and disadvantages of each idea against its performance, cost aesthetics etc is valued.
After evaluation, the best design is emerged. This final design with every detail is furnished in last step-ie communicating the 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 or less 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 is prepared.
(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.
2. Creative design is based on use of analogy and synthesis of alternatives – but engineering design is based on proven laws and past experience.
3. Creative design involves phases like incubation, illumination – but no such philosophy is followed in engineering designs.
4. Creative person is highly intuitive and independent in thinking and usually resists working in group – but engineering designers like teamwork.
5. Customs, habits and traditions are enemies of creativity – but the same are required in engineering design.
3.9. Divergence, Transformation & Convergence (S’97 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 a given design problem. Thus, these activities belong to the Divergence phase.
That activity wherein 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, by eliminating unwanted ideas.
3.10. Design Process Using Advanced Technology (W”00)
Although Engineering is a major sector of the economy in a developing country. It has not been benefited greatly from advances in computer technology. Engineers still use computers 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 the design process and play no fundamental role in aiding design. It aids only in the final drafting of the specifications. Computer-aided Design, (CAD) means a class of tools for crating drawing, or the physical description of the object. CAD systems have been sophisticated and 2D and 3D models are available.
The CAD allows the designer to conceptualize objects more easily. The design process in CAD system consists of the following stages.
1) Geometric modeling
2) Analysis and optimization
3) Evaluation4) Documentation and drafting.

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