Product development is not a generic process and should be modified on a case by case basis to suit the needs of the differing markets and stakeholder needs.
The design process is necessarily consultative. A steering group should be consulted throughout – most critically at formal review points where decisions are made regarding suitability of emerging solutions. These groups should include representatives of the anticipated range of users in terms of physical capabilities and cultural backgrounds.
The vagaries of human interaction with new products cannot be predicted by the designer and priority should be given to the production of proof-of-concept models from early in the process to be able to learn from their testing. Look for the flaws in design proposals rather than try to prove they are suitable and in this way the robustness of the solution is developed.
Prototypes are the most effective way of eliciting feedback from stakeholders and designers should be adept at rapidly producing 3D models for this purpose. In addition, working demo models should be produced to assess any electronic functions for assessment during design stage. In this way the risk of unforeseen issues with the manufactured product is significantly reduced. You should not proceed to the manufacture of a product unless each key function has been verified by the testing of a prototype according to the Verification Plan – this stance ultimately minimises time and cost to completion.
