PRODUCT DESIGN AND DEVELOPMENT
by Karl T. Ulrich & Steven D. Eppinger
- Part 3
Robert Bjärnemo
Division of Machine Design at the Department of Design Sciences
Lund Institute of Technology at Lund University
Product Specifications
p 91
What are Product Specifications?
p 92
Customer needs are generally expressed in the ”language
of the customer.”
In order to provide specific guidance about how to design and
engineer a product, development teams establish a set of
product specifications, which spell out in precise,
measurable detail what the product has to do in order to be
commercially successful.
What are Product Specifications?
p 92
A product specification (singular) consist of a metric (egentligen metrik,
men bör här tolkas som mätbar egenskap hos produkten) and a value
(värdeproblematik är central i all produktutveckling, då denna ger en antydan
av vad som gagnar vem när det gäller produkten och dess egenskaper –
här fokuserar vi på kvantitativa, mätbara, värden).
For example “average time to assemble” is a metric, while “less than 75
seconds” is a value.
Note that the value might take on several forms, including a particular
number, a range or an inequality. Values are always labeled with the
appropriate unit.
When are Product Specifications established?
p 74
Establishing Product Specifications
Alternative terms to product specifications are product
requirements, engineering characteristics or design
brief (design).
In Swedish: “produktspecifikation” (avseende listningen
av alla egenskaper produkten förväntas ha. Även
“kravspecifikation” är vanligt förekommande – trots att
alla egenskaper inte nödvändigtvis har rangen av att vara
krav.)
p 94
Establishing Target Specifications
.
p 93
Start with the
Customer Needs
Note, that the list above represents only half of the contents in the list on p 93
Establish Product Specifications
p 74
Establishing Target Specifications
The process of establishing target specifications contains four
steps:
Step 1: Prepare a list of metrics
Step 2: Collect competitive benchmarking information.
Step 3: Set ideal and marginally acceptable target values.
Step 4: Reflect on the result and the process.
p 74
Establishing Target Specifications
Guidelines to be considered when constructing the list of
metrics
Metrics should be complete.
 Metrics
should be dependent, not independent,
variables.
 Metrics should be practical.
 Some needs cannot easily be translated into quantifiable
metrics.
 The metrics should include the popular criteria for
comparison in the marketplace.

p 76
Step 1: Prepare the List of Metrics
Establish Metrics and Units
.
p 76
Step 1: Prepare the List of Metrics
Link Metrics to Needs
.
p 77
Step 2: Collect the Competitive Benchmarking
Information
Competitive benchmarking based on Metrics
.
p 80
Step 2: Collect the Competitive Benchmarking
Information
p 82
Competitive benchmarking based on perceived satisfaction of needs
.
More dots corresponds
to greater perceived
satisfaction of the
needs.
Step 3: Set Ideal and Marginally Acceptable
Target Values for Each Metric
There are five ways to express the values of the
.
metrics:





At least X – higher is better
At most X – lower is better
Between X and Y
Exactly X
A set of discrete values X, Y, Z
p 79
Step 3: Set Ideal and Marginally Acceptable
Target Values for Each Metric
The target specifications
.
p 84
Övning 3: Upprätta en produktspecifikation för en
kulspetspenna – baserat på ett specifikt
kundbehov!
Customer need: The pen writes smoothly (sv smidigt, jämnt,
mjukt, väl).
Product Specification = Metric and its corresponding value