CONCEPT SELECTION. Chapter 9

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Perancangan Produk - Genap 2016/2017

CONCEPT SELECTION Chapter 9

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Concept Development & Selection Process Mission Statement

Identify Customer Needs

Establish Target Specifications

Generate Product Concepts

Select Product Concept(s)

Test Product Concept(s)

Set Final Specifications

Plan Downstream Development

Perform Economic Analysis Benchmark Competitive Products Build and Test Models and Prototypes

These activities can occur throughout the design process!

•  Product concept selection is a decision process, in

which the design team selects one or a few product concept for further development.

Development Plan

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Challenges •  How to choose the best concept of abstraction? •  How to embrace all inputs (likings and concerns)

from the whole team in the decision process? •  How to make use of good attributes of otherwise weak concept designs? •  How to document the decision process?

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Concept Selection Approaches •  External decision •  By use of an external group of customers, clients, etc. •  Product champion & intuition •  By an influential member of the development team •  Multi-voting •  Asking each member to pick a number of concepts and pick the one with

most votes. •  Pros and cons •  The team list the strengths and weakness of each concept. •  Prototype and test •  Build and test prototype for each concept and select based on the test data. •  Decision metrics •  The team rates each concept against selection criteria with varying importance/weights.

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Issues in the decision process •  It assumes that the selection criteria reflect customer’s needs •  It assumes that the selection criteria are independent •  Manufacturing costs and manufacturability are not included in

the decision •  It is better to directly evaluate those independent, simpler concepts underpinning the design concepts, if they constitute all the product concepts. •  The process of concept selection can be applied to throughout the development process.

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Concept Selection Process

Concepts

Scoring Stage

Selection Criteria

Screening Stage

Concept Ratings

Winning Concept(s)

Goal: The goal is not to select the best concept but to develop the best concept by combining and/or refining

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Concept Development & Selection Funnel

concept generation concept screening concept scor ing concept testing

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Two stages of concept selection •  Concept screening •  To quickly narrow the number of concepts and to improve the concepts •  The Pugh concept selection method •  Concept scoring •  weighs the relative importance of the selection criteria •  focus on more refined comparisons with respect to each criteria

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Concept Selection Process Concept Selection Process

Screening Stage Prepare the Matrix Rate Concepts Rank Concepts Combine and Improve Select Best Concept Reflect on the Process

Scoring Stage Prepare the Matrix Rate Concepts Rank Concepts Combine and Improve Select Best Concept Reflect on the Process

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Concept Selection Process Prepare the Matrix

Rate Concepts

Rank Concepts

•  Criteria •  Reference Concept •  Weightings

•  Scale (– 0 +) or (1–5) •  Compare to Reference Concept or Values

•  Sum Weighted Scores

Reflect on the Process

Select the Best Concept

Combine and Improve

•  Continuous Improvement

•  May Be More than One •  Beware of Average Concepts

•  Remove Bad Features •  Combine Good Qualities

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Concept Selection Example

Reusable syringe

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Mission Statement •  Product description: •  Reusable syringe with precision dosage control for outpatient use. •  Primary market •  Elderly

•  Major features: •  Accuracy of dose metering •  Inexpensive

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Need analysis •  Ease of handling •  Ease of use •  Readability of dose settings •  Accuracy of dose metering •  Durability •  Ease of manufacture •  Portability

7 Product Concepts

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Konsep A: Master Silinder (Master Cylinder) •  Batas daerah tangkai 1/11 rongga à penempatan pendorong 1/11 dari posisi alat penyedot Konsep B: Rubber Brake •  Putar alat penyedot 90° untuk mengatur dosis atau menyimpan penyedot Konsep C: Roda Bergigi Searah (Ratchet) •  Putar alat penyedot 90° dan dorong ke belakang untuk mengatur dosis. Balikkan untuk memasang penghubung Konsep D: Plunge Stop (Penyedot Henti) •  Putar klep ke depan untuk mengatur dosis, dorong dengan alat penyedot

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Konsep E: Swash Ring •  Untuk mengatur dosis putar cincin pengatur dosis, tarik alat penyedot dan dorong untuk menyuntikkan

Konsep F: Pengungkit/Tuas •  Mengatur dosis dengan mendorong tuas ke depan dan menyuntikkan dengan mendorong tuas ke belakang

Konsep G: Drill Screw (Sekrup Pemutar) •  Mengatur dosis dengan memutar tombol pengatur dosis, menyuntikkan dengan menekan aktuator

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Concept screening principles •  Be focused on customer needs •  Match or exceed competitors’ performance along key

dimensions •  Improve the product’s manufacturability •  Reduce lead time •  Encourage more and effective participation from the design team members •  Have better documentation of the decision process.

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Screening stage

✔

✔

✔

✔

✔

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Eliminated Concepts

Concepts need to be well-defined PRIOR to concept evaluation! (neither of these concepts made the screening cut)

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Identify “Winning” Concepts

Concept A has highest net score and no “worse than” ratings

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Combine Winning Concepts

Concepts D & F were combined to eliminate “worse than” ratings

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Refine Winning Concepts

Concept G’s scored well but ease of handling was a problem, therefore revise!

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Scoring stage 1.  REFINE Pugh’s Matrix •  Criteria – dekomposisi kriteria •  contoh: kemudahan penggunaan à kemudahan penyuntikan, kemudahan

untuk dibersihkan, kemudahan untuk diisi

•  ADD Weightings

2.  Rate Concepts •  REFINE Scale •  1 – sangat buruk dibandingkan referensi •  2 – buruk dibandingkan referensi •  3 – sama seperti referensi •  4 – lebih baik dari referensi •  5 – sangat lebih baik dari referensi

•  Select “Average” Criteria for Reference •  Compare to Reference Criteria

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Scoring stage 3.  Rank Concepts •  Sum Weighted Scores n

s j = ∑ rij wi i=1

4.  Combine and Improve •  Remove Bad Features •  Combine Good Qualities 5.  Select Best Concepts •  May Be More than One 6.  Reflect on the Process •  Continuous Improvement

Dimana: rij = nilai konsep j untuk kriteria wi = bobot untuk kriteria I n = jumlah kriteria sj = total nilai untuk konsep j

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Concept Scoring Stage Generated from Customer Needs – week 1 Concepts A (reference) Master Cylinder

DF

E

G+

Lever Stop

Swash Ring

Dial Screw+

Selection Criteria

Weight

Rating

Weighted Score

Rating

Weighted Score

Rating

Weighted Score

Rating

Weighted Score

Ease of Handling

5%

3

0.15

3

0.15

4

0.2

4

0.2

Ease of Use

15%

3

0.45

4

0.6

4

0.6

3

0.45

Readability of Settings

10%

2

0.2

3

0.3

5

0.5

5

0.5

Dose Metering Accuracy

25%

3

0.75

3

0.75

2

0.5

3

0.75

Durability

15%

2

0.3

5

0.75

4

0.6

3

0.45

Ease of Manufacture

20%

3

0.6

3

0.6

2

0.4

2

0.4

Portability

10%

3

0.3

3

0.3

3

0.3

3

0.3

Total Score Rank Continue?

2.75

3.45

3.10

3.05

4

1

2

3

No

Develop

No

No

Need to revisit PUGH Matrix as your team’s knowledge base expands

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Final Winning Concept – DF (Tuas henti/ lever stop)

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Final Winning Concept - DF •  Concept DF was selected as the winning concept

HOWEVER: •  Do not simply select concept was highest rating – conduct a

sensitivity study by varying weights and ratings and examine effect on winning concept rating. Does uncertainty about a particular value have a large impact on the winning concept? •  Team could have decided to go with top two (or more) concepts. Concepts could be prototyped and tested for customer feedback.

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Tips for Concept Development & Selection •  When possible, use objective rather subjective criteria •  Useful to identify strengths of concepts that do not make it

through screening/scoring stages – could these be incorporated on winning concept(s)? •  Include ease of manufacture, reduced liability, and/or cost as criteria

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TO BE CONTINUED

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CONCEPT SELECTION. Chapter 9

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