Identifying Constraints. - PowerPoint PPT Presentation

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Identifying Constraints.

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The attached narrated power point presentation explains the methods to identify design constraints. – PowerPoint PPT presentation

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Date added: 10 December 2024
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Title: Identifying Constraints.


1
Identifying Constraints
  • MEC

2
Contents
  • Introduction.
  • Theory of Constaints.
  • Features of Constraints.
  • Constraints vs Objectives.
  • Combined Objectives - Constraints Tree.
  • Examples.

3
Constraint
4
Constraint
5
Theory of Constraints
  • An overall management philosophy introduced by
    Eliyahu M. Goldratt in his 1984 book titled The
    Goal.
  • Goldratt adapted the concept to project
    management with his book Critical Chain,
    published in 1997.
  • The rate of goal achievement by a goal oriented
    system (i.e., the system's throughput) is limited
    by at least one constraint.

6
Theory of Constraints
  • If there was nothing preventing a system from
    achieving higher throughput (i.e., more goal
    units in a unit of time), its throughput would be
    infinite which is impossible in a real-life
    system.
  • Organizations can be measured and controlled by
    variations on three measures throughput,
    operational expense, and inventory.

7
Constraints and Goals
  • Only by increasing flow through the constraint
    can overall throughput be increased.
  • Identify the system's constraint(s).
  • Decide how to exploit the system's constraint(s).
  • Subordinate everything else to exploitation
    decision(s).
  • Alleviate the system's constraint(s).
  • If in the previous steps a constraint has been
    broken, go back, but do not allow inertia to
    cause a system's constraint.

8
Constraint Cycle

9
Misidentifying a Constraint

You thought the real constraint is upstream!
10
Dealing with Constraints- Adding Capacity
Upstream

11
Misidentifying a Constraint
You thought the real constraint is downstream!

12
Dealing with Constraints- Adding Downstream
Capacity
13
Focusing Steps

14
Design Constraints
  • A limit or restriction on the designs behaviors
    or attributes.
  • Identifying limits that cannot be exceeded and
    boundaries that may not be crossed.
  • Are there things or circumstances you want us to
    avoid?
  • Framed as a binary yes-or-no choice.
  • Limit the size of a design space.
  • Exclusion of unacceptable alternatives.

15
Safe Ladder Constraints
Constraints as a kind of checklist. Keep our
list of possible designs to a reasonable
length. May be expressed in terms of specific
numerical values.
16
Juice Container Constraints
17
Constraints vs Objectives
Constraints Objectives
Limit the size of the design space. Permit to explore what remains in that design space
Enable us to reject unacceptable alternatives. Enable us to select among design alternatives that are at least acceptable
Designs that satisfy are accepted. Designs that satisfice may not be optimal or the best.
18
Constraints vs Objectives
  • Design an affordable toy vehicle using
    biodegradable material alone.
  • Objective To design a toy vehicle, should be
    affordable.
  • Constraint Use of biodegradable material.
  • Cost can become a constraint (say below Rs.
    25/-).
  • Objectives are desirable attributes.
  • Constraints are required attributes.

19
Objectives Tree-Juice Container
20
Combined Objectives and Constraints Tree - Juice
Container
Constraints in Italics Boxes differently shaped
21
Combined Objectives and Constraints Tree
  • Combined Tree communicates how objectives and
    constraints interact.
  • Constraints are related to but are different from
    objectives.
  • Constraints help us prune or narrow our space of
    designs.
  • Constraints help us do our screening and
    evaluation of designs.

22
Constraints
  • Design of a widely used product to be done in a
    more constrained design space than client- or
    user-specific devices.
  • Constraints lists prepared by different teams may
    differ rather markedly.
  • Different teams may identify different limiting
    values for the same constraint.
  • Constraints may sound binary or fuzzier.
  • There may be differences in granularity.

23
List of Constraints for an Arm Support Team A
MORE GRANULAR
24
List of Constraints for an Arm Support Team B
Compact
25
Types of Constraints
Affected Parameter?
26
Reference
  • Clive L Dim, Patrick Little and Elizabeth J
    Orwin, Engineering Design, A Project Based
    Introduction, 4th Edition, Wiley, U.S.A, 2014.
  • https//medium.com/praxis-blog/theory-of-constrain
    ts-106-the-five-focusing-steps-741f1b770bf1

27
Thank You
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