Detailed design  Variability in the process is reduced here through high levels of  standardisation of skills, processes and the designs themselves.  This helps eliminate waste and rework which allows greater  flexibility of capacity. Detailed standardisation also maximiseslearning and continuous improvement.

Prototype /Tools  Two sets of prototype tooling are usually produced, not to test solutions but to choose the different sub-systems and check their  integration. Engineering changes will not be accepted after this  phase. This is an intensive period for system design  manufacturing and quality engineers.

Set based engineering enables many different solutions for a design can be worked on and matured at one time.  As the development time increase and moves closer to the start of production unsuitable solutions are stopped but kept on file so potentially could be used for the next new product.  The main advantage of set based concurrent engineering is that if the design concept that is chosen fails to meet customer requirements it can be quickly replaced by a robust and mature alternative solution.

Conventional engineering usually starts with the generation of new concepts and ideas too, however the main difference is that the final solution is agreed at a very early stage of the development.  This could be before all the other component final designs are decided/understood.  Therefore, as the design stages mature if problems are found the solution may have to be reworked several times to ensure it still meets the customer requirements.  The major disadvantage of this process is that usually problems are not found until later in the development stages, sometimes as late as after the start of manufacturing.  Fixes problems that occur at this stage is much more expensive as you are now trying to change actual components instead of designs on paper.