Specifying requirements before starting a development program

by 22 augustus, 2016 0

A program specification is the document that kicks of the creation of the five structured entities

After some deliberations a company may decide to go for the introduction of a new product.  A single project, or a program consisting of several  projects is started. A program specification is required to kick of the creation of  the five elements: functions, a product, a manufacturing proces, projects and competences.

Our aim is get away for a written specification document and go towards specification data in a data-base, using the same change management as in engineering change management.

The role of a product functions in a program specification

Describing the product functions in one thing, specifying their required performance is the real deal of writing a function specification. Two products can have the same function, and their design can be completely different in order for one to achieve a higher performance than the other. So, the required performance must be specified before starting the design.
Similarly, the environmental conditions in which the functions are to be performed must be specified. Performing in arctic conditions may require a radical different design for a digger than one that is to dig in the Sahara desert.
Designing a function is specifying a function.

A function specification will have to prescribe the way in which the design will be tested for conformance to the functional requirements.

Any requirement specification will have to mention the regulations under which the product is to perform.

The function specification will mature into a requirement spec for sub-functions and eventually crosses over in a product spec: the requirements for the design-elements that perform the function. For the designer chooses properties for his part to have, such that he believes necessary for the part to perform its function. Designing a part means choosing material, specifying dimensions and prescribing properties like strength, hardness, surface roughness. Designing a part is specifying a part.

And by the way, these semantics caused a big dent in my self-esteem: what I produce is a lot of paper specifying my design for others to make. Gosh, I am not a creator, I am a bureaucrat.

The program specification and the other four elements of creation

Creating the product.
The program specification may very well interfere with the design freedom and prescribe certain design solutions, or design attributes. Designers may be prescribed to use existing solutions or COTS parts.

Largely defining the design of the product (and the manufacturing process) is the required qantity of products to be produced.

Also, targets can be set for certain product attributes like costs, weight, MTBF, MTTR. The actual performance for such requirements can be predicted in the design phase with increasing accuracy, from a rough estimate to a calculated value. The performance is to be monitored during the design stage and managed in the required direction. If the target is missed, production will not wait and costly and lengthy redesign may be needed to get on target.

It can be debated whether Cost of goods (the manufacturing costs of an item) is a property of an item. The manufacturing cost depend heavily on the labor involved in fabricating parts and assembling the product. So, if we ignore material cost and the influence of the batch size, is CoG rather a property of the manufacturing process design than of a product design?

Creating the production process
The requirement specification needs to specify the required production quantity and the production speed. A manufacturing process cannot be designed without these performance specifications.

Creating the projects in the program
The requirements specification will mention a certain required introduction date for the new product. Without that, the creation of project plans cannot start; the required effort cannot be estimated, etc.

Creating the required competences
The requirements specification is a first indication for HR&O whether the available competences in the company can do the job or whether that additional hiring (or outsourcing) is required.

We conclude that the program spec is what gets the creation going of all five elements of design. The main function specification, the required quantity of products per year and the planned moment of introduction are the key elements of the program spec. These are the variables that are set in the business plan

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