Product Design & Development

Product Design & Development

Product Specifications

ETM 551 Product Design and Development -Lecture 4

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What are specifications? • Specifications spell out in precise, measurable detail what the product has to do. • Specifications represent an unambiguous agreement on what the team will attempt to achieve in order to satisfy the identified customer needs. • Must include regulatory and agency approval requirements ETM 551 Product Design and Development -Lecture 4

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Concept Development Process Development Plan Identify Customer Needs

Establish Target Specifications

Generate Product Concepts

Select Product Concept(s)

Test Product Concept(s)

Set Final Specifications

Plan Downstream Development

Mission Statement Perform Economic Analysis

Benchmark Competitive Products

Build and Test Models and Prototypes

Target Specs

Final Specs

Based on customer needs and benchmarking

Based on selected concept, feasibility, models, testing, and trade-offs ETM 551 Product Design and Development -Lecture 4

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Product specifications • Other names for ‘product specifications’ – Product requirements – Technical specifications


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Product Specifications Example: Mountain Bike Suspension Fork


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A specification • A ‘specification’ (sing.) consists of a metric and a value Example: metric → “Average time to assemble” value → “less than 75 seconds”


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When are specs established? • For simple products (e.g., soap): early in the development process, right after identifying customer needs • For technology-intensive products: at least twice …


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For technology-intensive products • Target specifications – (representing hopes and aspirations) are set immediately after the team has identified the customer needs it aims to meet.

• Refined specifications – (i.e., the specs the team aims to achieve) are documented in the project´s “contract book”. ETM 551 Product Design and Development -Lecture 4

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Target specifications To establish target specs: • Prepare list of metrics, using the needs/metrics matrix. • Collect benchmarking information. • Set ideal and marginally acceptable target values for each metric. • Reflect on results and process. ETM 551 Product Design and Development -Lecture 4

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Metrics • Prepare a list of metrics The underlying assumption is that consumer needs can be translated into precise, measurable specs and that meeting specs will result in satisfaction of the associated customer needs.


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The Product Specs Process • Set Target Specifications – Based on customer needs and benchmarks – Develop metrics for each need – Set ideal and acceptable values

• Refine Specifications – Based on selected concept and feasibility testing – Technical modeling – Trade-offs are critical

• Reflect on the Results and the Process – Critical for ongoing improvement ETM 551 Product Design and Development -Lecture 4

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Start with the Customer Needs

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The suspension The suspension The suspension The suspension The suspension The suspension The suspension The suspension The suspension The suspension Th i

NEED reduces vibration to the hands. allows easy traversal of slow, difficult terrain. enables high speed descents on bumpy trails. allows sensitivity adjustment. preserves the steering characteristics of the bike. remains rigid during hard cornering. is lightweight. provides stiff mounting points for the brakes. fits a wide variety of bikes, wheels, and tires. is easy to install. k ith f d ETM 551 Product Design and Development -Lecture 4

Imp 3 2 5 3 4 4 4 2 5 1 1 12

… but remember • Metrics should be dependent, NOT independent, variables. • Metrics should be practical. • Some needs cannot be easily translated into quantifiable metrics (subjective needs). • Metrics should include popular criteria used for ‘marketplace’ comparisons. ETM 551 Product Design and Development -Lecture 4

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Metric #

Need #s

Establish Metrics and Units

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1,3 2,6 1,3 1,3 4 5 5 6 7 8 9 9 9 9 10 11

Metric Attenuation from dropout to handlebar at 10hz Spring pre-load Maximum value from the Monster Minimum descent time on test track Damping coefficient adjustment range Maximum travel (26in wheel) Rake offset Lateral stiffness at the tip Total mass Lateral stiffness at brake pivots Headset sizes Steertube length Wheel sizes Maximum tire width Time to assemble to frame ETM 551 Product Design and Fender compatibility Development -Lecture 4

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Units dB N g s N-s/m mm mm kN/m kg kN/m in mm list in s list14

Metrics Exercise: Ball Point Pen • Customer Need: – The pen writes smoothly.

• Metric(s): 1. Variation in line thickness (mm) 2. Variation in ink coverage (cc/mm2) 3. Functional range of writing force (N) 4. Functional range of writing velocity (mm/sec) 5. Functional range of pen angle from vertical (deg) 6. Variation in resistance to translational motion (N)

Assuming that smooth writing can be characterized by: • Good quality line • Preservation of line quality • Ease of use...

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Needs vs. Metrics


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Benchmarking • No product development team can expect to succeed without ‘benchmarking’ the project against competing products – Warning: Data in competitors’ catalogues and supporting literature may not be accurate. Values for key metrics should be verified by independent testing and observation.


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1 2 3 4 5 6 7 8 9 10

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12 13 14 15 16 17

1,3 2,6 1,3 1,3 4 5 5 6 7 8

9 Headset sizes

9 Steertube length 9 9 10 11 12

Wheel sizes Maximum tire width Time to assemble to frame Fender compatibility Instills pride

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Gunhill Head Shox

Tonka Pro

Rox Tahx Ti 21

Rox Tahx Quadra

Imp 3 3 5 5 3 3 3 3 4 2

Maniray 2

Metric Attenuation from dropout to handlebar at 10hz Spring pre-load Maximum value from the Monster Minimum descent time on test track Damping coefficient adjustment range Maximum travel (26in wheel) Rake offset Lateral stiffness at the tip Total mass Lateral stiffness at brake pivots

ST Tritrack

Need #s

Metric #

Benchmark on Metrics

Units dB N g s N-s/m mm mm kN/m kg kN/m

8 550 3.6 13 0 28 41.5 59 1.409 295

15 10 760 500 3.2 3.7 11.3 12.6 0 0 48 43 39 38 110 85 1.385 1.409 550 425

15 710 3.3 11.2 200 46 38 85 1.364 425

9 480 3.7 13.2 0 33 43.2 65 1.222 325

13 680 3.4 11 0 38 39 130 1.1 650

in

1.000 1.125

1.000 1.125 1.250

1.000 1.125

1.000 1.125 1.250

1.000 1.125

NA

140 165 190 215

150 170 190 210

150 190 210 220

NA

26in 1.75 35 none 4

26in 1.5 45 none 3

26in 1.5 35 none 3

26in 1.5 85 all 5

5

mm

150 180 210 230 255

5 5 1 1 5

list in s list subj

26in 1.5 35 Zefal 1


150 170 190 210 230 26in 700C 1.75 45 none 5

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The suspension The suspension The suspension The suspension The suspension The suspension The suspension The suspension The suspension The suspension The suspension


• •• • • •••• • • • •••• •••• •••

•••• •••• ••••• •••• •• ••• ••• •••• ••••• ••••• •

•• ••• •• •• • • • ••• ••• •••• •

Gunhill Head Shox

Tonka Pro

Rox Tahx Ti 21

Imp 3 2 5 3 4 4 4 2 5 1 1

Rox Tahx Quadra

NEED reduces vibration to the hands. allows easy traversal of slow, difficult terrain. enables high speed descents on bumpy trails. allows sensitivity adjustment. preserves the steering characteristics of the bike. remains rigid during hard cornering. is lightweight. provides stiff mounting points for the brakes. fits a wide variety of bikes, wheels, and tires. is easy to install. works with fenders

Maniray 2

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ST Tritrack

Benchmark on Customer Needs

••••• •• ••••• ••• ••••• •• ••••• •• •• ••• ••••• • ••• •••• ••• •• ••••• ••• •••• ••••• • •

••• ••••• ••• ••• ••••• ••••• ••••• ••••• • • •••••

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Setting target values • Set ideal and marginally acceptable target values for each metric. – At least X – At most X – Between X and Y – Exactly X – A set of discrete values


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1 2 3 4 5 6 7 8 9 10

11 Headset sizes

Units dB N g s N-s/m mm mm kN/m kg kN/m in

12 Steertube length

mm

13 14 15 16

list in s li t

Wheel sizes Maximum tire width Time to assemble to frame F d tibilit

Ideal Value

Metric Attenuation from dropout to handlebar at 10hz Spring pre-load Maximum value from the Monster Minimum descent time on test track Damping coefficient adjustment range Maximum travel (26in wheel) Rake offset Lateral stiffness at the tip Total mass Lateral stiffness at brake pivots

Marginal Value

Assign Marginal and Ideal Values >10 >15 480 - 800 650 - 700 1.5 >1.75 1.75