Developing

Product Design Specifications

Chapter 5, Ulrich & Eppinger text

IDENT

OPP

DEFINE

PROBLEM

GEN

CONCEPTS

GATHER

INFO IMPLEMENT

SCREEN

CONCEPTS HANDOFF

ME 4054W Design Projects

January 26, 2012

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When are product requirements established?

Identify

customer

needs

Establish

target

requirements

Generate

concepts

Select

concept

Refine

requirements

Detail design, test, prototyping

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What is a Product Design Specification?

A Product Design Specification (PDS):

◦ Is a documented statement of what the product is to do

◦ Is a living document, but defined early

◦ Is driven by customer needs

◦ Shows what you are trying to achieve

◦ Contains:

List of Customer Needs

Design Specifications

Customer Needs Example:

Bicycle Suspension Fork

UNIVERSITY OF MINNESOTA Exhibit 5-2 from text

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Establishing Target Specifications

1. Prepare a list of metrics from the needs

2. Collect competitive benchmarking information

3. Set ideal and marginally acceptable target values

4. Reflect on the results and process

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Metrics

The metrics should be:

– Complete

– Practical

– Expressed as a dependent variable (what, not how)

– Derived from a customer need

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The vast majority of the metrics should be objective and numeric with units

◦ For example lb, $, inch, N-m, etc.

Metrics can also be subjective and binary.

◦ For example, “Aesthetically pleasing” and “Meets the ISO-xxxx Safety Standard”.

Metrics

List of Metrics Example:

Bicycle Suspension Fork

UNIVERSITY OF MINNESOTA Exhibit 5-4 from text

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Competitive Benchmarking

The relationship of the new product to competitive products is critical in determining its potential for success in the marketplace.

Having a product that is meaningfully better than its competitors on high priority needs creates differentiation and increases the likelihood of commercial success.

Gathering information on competing products is the best way to understand the relative position of the proposed product with respect to its competitors and helps to validate the specs.

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Competitive Benchmarking

This is an abbreviated list. See Exhibit 5-6 in the text.

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Target values

Targets are set by considering: ◦ Today’s competition

◦ Competitor’s future capabilities

◦ The product’s mission statement and target market segment

Targets can be expressed as: ◦ Exact (1.5 inches)

◦ Less than (< 1 inch)

◦ Greater than (> 1 inch)

◦ Range (1.5 – 2.0 inch)

◦ A set of discrete values (1.0, 1.5, 2.0 inch)

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Example: Product Specifications for a

Bicycle Suspension Fork

This is an abbreviated list of product specs for the suspension fork. See Exhibit 5-8 in the text.

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Establishing Target Specifications,

redux

1. Prepare a list of metrics from the needs

2. Collect competitive benchmarking information

3. Set ideal and marginally acceptable target values

4. Reflect on the results and process

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Establishing Final Specifications

1. Develop technical models for the product

2. Develop a cost model of the product

3. Refine the specifications, making trade-offs where necessary

4. Flow down the specifications as appropriate

5. Reflect on the results and the process

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Bottom Line

The design requirements in the PDS must:

– reflect customer need

– differentiate the product from the competition

– be technically and economically feasible

Sandy Cutler, CEO of Eaton, asks his engineers:

• Is the customer asking for it?

• What differentiation does it offer Eaton?

• What value does it offer the customer?