Chapter 3 MITS Gwalior

1. Description of
Design Process
CONCEPTS IN ENGINEERING DESIGN
Chapter 3 - 41

2. The design
activities
2

3. 3
PRODUCT DEVELOPMENT

4. 4
Planning for Manufacture
 A method of manufacture must be established for each component in the system.
 A process sheet is created; it contains a sequential list of all
manufacturing operations that must be performed on the component.
 The information on the process sheet makes possible the estimation of the
production cost of the component. High costs may indicate the need for a change in
material or a basic change in the design.

5. 5
Planning for Distribution
 Important technical and business decisions must be made to provide for the effective
distribution to the consumer of the products that have been produced.
 The economic success of the design often depends on the
skill exercised in marketing the product.
 If it is a consumer product, the sales effort is concentrated on advertising in print and
video media, but highly technical products may require that the marketing step be a
technical activity supported by specialized sales brochures, performance test data,
and technically trained sales engineers.

6. 6 Planning for Use
 The use of the product by the consumer is all-important.
 The following specific topics can be identified as being important user-
oriented concerns in the design process:
• Ease of maintenance,
• Durability,
• Reliability,
• Product safety,
• Convenience in use (human factors engineering),
• Aesthetic appeal, and
• Economy of operation.
 It is becoming increasingly important with the growing concerns for consumer
protection and product safety.

7. 7
Planning for Retirement
 The final step in the design process is the disposal of the product when it has
reached the end of its useful life.
 Design for the environment , also called green design, has become an
important consideration in design. As a result, the design of a product should
include a plan for either its disposal in an environmentally safe way or, better,
the recycling of its materials or the remanufacture or reuse of its components.

8. 8
Product Life Cycle

9. 9

10. Conceptual design
 Conceptual design is the process by which the design is initiated, carried to the
point of creating a number of possible solutions, and narrowed down to a single
best concept. It is sometimes called the feasibility study.
 Conceptual design is the phase that requires the greatest creativity, involves the
most uncertainty, and requires coordination among many functions in the business
organization.
10

11. The following are the discrete activities that we
consider under conceptual design.
 Identification of customer needs: The goal of this activity is to completely
understand the customers’ needs and to communicate them to the design
team.
 Problem definition: The goal of this activity is to create a statement that
describes what has to be accomplished to satisfy the needs of the customer.
This involves analysis of competitive products, the establishment of target
specifications, and the listing of constraints and trade-offs.
 Gathering information: Engineering design presents special requirements over
engineering research in the need to acquire a broad spectrum of information.
 Conceptualization: Concept generation involves creating a broad set of
concepts that potentially satisfy the problem statement. Team-based creativity
methods, combined with efficient information gathering, are the key activities.
11

12.  Concept selection: Evaluation of the design concepts, modifying and
evolving into a single preferred concept, are the activities in this step. The
process usually requires several iterations.
 Design review: Before committing funds to move to the next design phase,
a design review will be held. The design review will assure that the design
is physically realizable and that it is economically worthwhile. It will also
look at a detailed product development schedule. This is needed to devise
a strategy to minimize product cycle time and to identify the resources in
people, equipment, and money needed to complete the project.
12

13. MISSIONSTATEMENT
Product Description
Key Business Goals
Primary Market
Secondary Markets
Assumptions
Stakeholders
13

14. PROBLEMSTATEMENT
14

15. BENCHMARKING
 Benchmarking is a process for measuring a company’s operations against the best
practices of companies both inside and outside of their industry.
 It is a way to learn from other businesses through an exchange of information.
 Benchmarking operates most effectively on a quid pro quo basis.
 Benchmarking is usually introduced by a manager who has studied it after learning about
success experienced by other companies using the process.
15

16. NEED OF BENCHMARKING
 Select the product, process, or functional area of the company that is to be
benchmarked. That will influence the selection of key performance metrics that will
be measured and used for comparison. From a business viewpoint, metrics might
be fraction of sales to repeat customers, percent of returned product, or return on
investment.
 Identify the best-in-class companies for each process to be benchmarked. A best
in-class company is one that performs the process at the lowest cost with the
highest degree of customer satisfaction, or has the largest market share.
16

17. RESISTANCE TO BENCHMARKING
 Fear of being perceived as copiers.
 Fear of yielding competitive advantages if information is traded or shared.
 Arrogance. A company may feel that there is nothing useful to be learned by
looking
 outside of the organization, or it may feel that it is the benchmark.
 Impatience. Companies that engage in an improvement program often want to
begin making changes immediately. Benchmarking provides the fi rst step in a
program of change—an assessment of a company’s relative position at the
current point in time.
17

18. FUNCTIONAL DECOMPOSITION18
 The stated goal of Pahl and Beitz was to “set out a comprehensive design methodology for
all phases of the product planning, design, and development process for technical systems.”
 A common strategy for solving any complex task or describing any complex system is to
decompose it into smaller units that are easier to manage.
 Functional decomposition is the second type of representational strategy common
in early stages of concept generation.
 Here the emphasis is on identifying the functions and sub functions necessary to achieve the
overall behavior defined by the PDS.

19. FUNCTIONAL DECOMPOSITION19

20. MORPHOGRAPHICAL CHARTS20
 Morphological analysis is a method for representing and exploring all the relationships
in multidimensional problems.
 The word morphology means the study of shape and form.
 Morphological analysis is a way of creating new forms.
 The general morphological approach to design is summarized in the following
three steps.
1. Divide the overall design problem into simpler sub problems.
2. Generate solution concepts for each sub problem.
3. Systematically combine sub problem solutions into different complete solutions and
evaluate all combinations.
 The morphological approach to mechanical design begins with the functional
decomposition of the design problem into a detailed function structure.

21. MORPHOGRAPHICAL CHARTS21
The advantage of creating a Morphological chart is that it allows a systematic
exploration of many possible design solutions. Following
are potential concepts.
 Syringe Design Concept 1— Concept 1 uses a hand pump (like with a blood
Pressure cuff) to excite the liquid. The user would insert a sharp, pointed tool to
penetrate the muscle tissue, gaining access for the medication. The medicine
would be allowed to flow through a rigid tube into the muscle area. No special
positioning method is considered with this concept.
 Syringe Design Concept 2— Concept 2 is similar except a piston and cylinder
arrangement would replace the pump for the first two functions. A shearing tool
for cutting the skin and muscle tissue is used in place of the pointed tool. Flexible
tube is used to convey the medication instead of a rigid tube. A strap and
cuff arrangement is used for positioning.

22. MORPHOGRAPHICAL CHARTS22

23. EMBODIMENT DESIGN23
Embodiment phase of design is divided into three activities
 Product architecture— determining the arrangement of the physical elements of the
design into groupings, called modules.
 Configuration design—the design of special-purpose parts and the selection of
standard components, like pumps or motors.
 Parametric design— determining the exact values, dimensions, or tolerances of the
components or component features that are deemed critical-to-quality
Conceptual
Design
Preliminary
(Embodiment)
Design
Detail Design

24. Embodiment phase of design
 Product architecture— determining the arrangement of the physical
elements of the design into groupings, called modules.
 Four Steps of Embodiment Design
1. Create a schematic diagram of the product.
2. Cluster the elements of the schematic.
3. Create a rough geometric layout.
4. Identify the interactions between modules.
24

25. Configuration Design25
Designofaboltedjoint

26.  Identify the likely ways the part might fail in service.
 Identify likely ways that part functionality might be compromised.
 Materials and manufacturing issues
 Design knowledge base
26

27. Parametric Design
 The objective of parametric design is to set values for the design variables that will
produce the best possible design considering both performance and cost
 Robustness means achieving excellent performance under the wide range of
conditions that will be found in service.
27

28. Detail Design
 Last stage of design process.
 It is the phase where all of the details are brought together, all decisions are
finalized, and a decision is made to release the design for production.
 Poor detail design can ruin a brilliant design concept and lead to
manufacturing defects, high costs, and poor reliability in service
 The reverse is not true - A brilliant detail design will not rescue a poor
conceptual design
 Detail design is the lowest level in the design abstraction hierarchy.
 Many decisions have been made to get to this point.
 Most of these decisions are very basic to the design and to change them
now would be costly in time and effort.
 Thus, detail design is mainly concerned with filling in the details to ensure
that a proven and tested design can be manufactured.
28

29. Chief
activities and
deliverables
of detail
design.
29

30. DETAIL DESIGN
 The first task of detail design is to complete the detail drawings.
 Although much of the work would have been done in Embodiment design,
still there may be some calculations to perform, questions to answer and
decisions to make.
 One important decision is - Make / Buy.
 Further, some tests have to be performed to assure that the components
and assemblies meet the requirements laid down in the product design
specification.
 As each component, subassembly and assembly is completed, it is
documented completely with detail drawings and specifications.
30

31.  The specifications contain information on:
The technical performance of the part
Its dimensions
Test requirements
Material requirements
Reliability requirements
Design life
Packaging requirements, and
Marking for shipment
 The specification should be sufficiently detailed to avoid confusion
at any stage.
 If the product design is complex, then it is necessary to impose a
Design Freeze at some point prior to completion.
no change permitted without approval
Design
Record
Document
31

32. Detail Design
 Once the design is finalized, a final prototype is built and qualification tested
to ensure that the design functions are as required, safe and reliable.
 Depending on the complexity of the product the qualification testing may
simply be to run the product during an expected duty cycle and under
overload conditions, or it may be a more elaborate series of staged tests.
 The detail drawing allow the calculation of detailed cost estimates.
 To make these calculations a bill of materials is drawn.
32

33. Detail Design
 Drawings must contain the information needed to
manufacture the product
 The drawings should be so complete that they leave no
room for misinterpretation
 The information on a detail drawing includes:
Standard views of orthogonal projection – top, front, side
Auxiliary views such as sections, enlarged views, isometric views
that aid in visualizing the component and clarifying the details
Dimensions – presented according to the GD&T standard
Tolerances
Material specification, and any special processing instructions
Manufacturing details, such as parting line location, draft angle,
surface finish
33

34. 34

35. Bill Of Material35

36. MISSIONSTATEMENT
Product Description
Key Business Goals
Primary Market
Secondary Markets
Assumptions
Stakeholders
36

37. MISSIONSTATEMENT
Product Description
Key Business Goals
Primary Market
Secondary Markets
Assumptions
Stakeholders
37