Design Input vs. Design Output - What constitutes Design Input?

tantan

Inactive Registered Visitor
#1
Hi all, i have read so much information on design control and still have no definitive conclusion on what constitutes design input.some documents say it is only the design requirements based on user needs and others indicate that it is both the requirments and the specifications.Or should we really be saying that the design specs are a design output!!??

tan :)
 

Jim Wynne

Super Moderator
#2
Re: design input vs output

What's the difference between design "requirements" and "specifications"?

Design input may take many different forms, ranging from a vague concept in someone's head, roughly sketched on a cocktail napkin to detailed specifications/requirements. In general, a thing that is the subject of design activities is expected to do something, and often what it's expected to do is described in terms of limits or ranges. A building must have x square feet of floor space, have a brick exterior and conform to local building codes, e.g.. Whatever the thing is supposed to do forms the basis of design input.
 

ScottK

Not out of the crisis
Staff member
Super Moderator
#3
Re: design input vs output

essentially what Jim says.

here how it is defined in our procedure:
3.1. Design Inputs inlcude:
3.1.1. Functional and performance requirements as determined by the Chief Engineer and/or customer.
3.1.2. Regulatory requirements
3.1.3. A review of previous, similar designs to extract any applicable information.
 

Patricia Ravanello

Quite Involved in Discussions
#4
The attached file illustrates the typical input and output of the Design process in an automotive parts manufacturing operation.

Inputs are on the left...outputs on the right. The rectangle in the center identifies the person responsible and the scope of activities to be completed.

Hope this helps.
Patricia
 

Attachments

#6
Design input is the requirements of the customer, plus the requirements of the organization.
The "cookie-cutter" type of process is a good learning tool, but if you depend on that approach for a "real" customer product, then you may find that you are doing more or less then what is needed.
 

Jim Wynne

Super Moderator
#7
The fact that all or most of the possible ingredients have been listed doesn't mean that they will all find their way into the batter. Remember--the OP was looking for examples, and Patricia's attachment filled the bill quite nicely. Cookie cutters aside, it's always possible to do too much or too little. We have to assume sometimes that people are not robots, and are capable of making rational decisions, given the necessary information.
 
#8
As I read the original post, it does not ask for a definition of design output:

"What constitutes Design Input?"
"What is the difference between "requirements" and "specifications"?

I must add that people who study these things will tell you that definition by example is the least useful form of definition. It is the difference between someone asking "What is a fruit?" and being told that it is the "edible reproductive body of a seed plant, especially one having a sweet pulp associated with the seed" and "things like apples, oranges, and pears." The latter is of limited value to someone who doesn't already know what a fruit is, since it enables them to recognize only apples, oranges, and pears as fruits. It tells them nothing about why these items are fruits, or how to identify other fruits as fruits. It does not contribute to an understanding what a fruit is. As I read the question, tantan seeks understanding.
 

Wilderness Woody

Involved In Discussions
#10
Hi all, i have read so much information on design control and still have no definitive conclusion on what constitutes design input.some documents say it is only the design requirements based on user needs and others indicate that it is both the requirments and the specifications.Or should we really be saying that the design specs are a design output!!??

tan :)
Think of SPECIFICATIONS as detailed limits on REQUIREMENTS. For example, a requirement for a new vehicle design may be "it needs to be fuel efficient"... now you need to be more specific about how efficient right?! The specification may call out a specific target range on a standardized test bed. There are all kinds of industry and military specifications used to define various material performance characteristics of products.

You may generate additional process or product specifications as outputs from your design activities in order to support the production of the product.
 

Top Bottom