How to write a ‘Product Design Specification’.

“Designing to requirements and walking on water are easy if both are frozen.” - Anon

Following on from my ‘post’ – Well written ‘Product Design Specifications’ (PDS) drive product success! – I thought I should expand and outline a good PDS structure.

The ‘PDS’ is an important document which states the full specification of requirements for a product and should be written at the outset of the project following on from the ‘design brief’. It is a guide to the project team of what is required of the product. The specification will be broken into smaller categories that will describe all of the elements that the design team will need to consider to provide a design solution and any constraints against which it will be measured. It will also state other requirements that other departments like Technical Publications, Quality and Marketing will have interest in. It is important that the document is unambiguous and if the client isn’t writing it, that they are in agreement with its scope.

The following is a typical contents list you might expect to include. Note this is not exhaustive and it is not a functional specification which may also be needed if the product has very elaborate functions, particularly if it is machinery or a complex electronic or electrical system. Describing what is required of the product in each of the following areas will go a long way to producing a good specification.

Customer/s – what are their needs

Quantity – expected volumes (remembering product variants if applicable)

Competition – what’s already in the marketplace and influencing factors

Environment – where does the product need to work

Product Cost – what will the market stand against what you intend to offer

Lead times – what is the development time and initial time for ready to ship product. Is there a particular deadline?

Installation, Maintenance & Repair – Consider if special tools will be required for installation and will the product be serviced in the field or in a service centre?

Intellectual Property – Is it patentable or suitable for design registration? Are you controlling the IP and who has access to it?

Legal & Safety – How will you guarantee safety through the supply chain or protect yourself against claims?

Budgetary constraints -  What Non-Returnable Expenditure (Tooling/Prototyping etc..) will be allowable?

Industrial Design – Is the product part of a family or a one off? Do you want it to stand out or blend in?

Materials – What materials might be suitable? Will the product need to be robust or have a disposable feel?

Ergonomics – How will the product be used and by whom? How flexible will the design need to be to cater for ‘all’?

Product life and Shelf life – How long will it be in service for? Does it need to power up after sitting on the shelf for 12 months?

Processes and Suppliers – What processes will you need in-house or what suppliers will you need to look for?

Product disposal and Sustainability – How will you take back the product at end of life, can parts be reused or recycled, perhaps upcycled?

Product Dimensions – Are there constraints on product size?

Performance  – How will it perform and how will you measure success? Is a functional specification required?

Testing in manufacturing cycle – What tests will be required to ensure product conformance?

Quality & Standards – Goods inwards inspection & Regulatory approvals need to be defined.

Packaging and Transit – What is the transit method and what is the impact on packaging styles?

Documentation – What manufacturing and user documentation is required. Will staff require training or maybe even the customers.

Remember the importance of ensuring that all the requirements are listed and that this is ‘frozen’ to ensure compliance and to avoid ‘feature creep’! It is also important that this document has a unique document reference and revision and contains within it a revision history and circulation list so that the project team is certain that the document they are consulting and discussing with each other remains at the same revision level!

Michael Holloway – 3Minds Limited.

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