Once concepts have been created, evaluated and the preferred one selected Engineering turns that concept into a set of drawings and specifications that unambiguously define the product, allowing it to be assembled and components to be manufactured or purchased. This means making hundreds or even thousands of small but interconnected design choices that together lead to a product that works, can be made and is appropriately optimised for value.
Make or Buy?
Most of our instrument designs contain a large number of off-the-shelf parts such as electronic components, fasteners, springs, bearings, motors/pumps/fans and lenses. Selection of catalog parts is not only based on cost and functionality, but also on availability (for prototypes and in volume), quality of documentation and support and expected continuity of supply. In the case of embedded software it can also make sense to license-in well-tested and documented module libraries rather than coding from scratch. Make-or-buy decisions will greatly depend on the expected production volume.
Computer Aided Design (CAD)
Where in the Concept Design phase we can still use pencil and markers, Engineering is exclusively done using various forms of CAD: 3-D mechanical CAD for the total product assembly and all custom-made parts—with suppliers in many cases directly producing parts from our 3-D files. e-CAD for electronics including circuit schematics and PCB layout. Various IDEs (Integrated Development Environments) to code and debug for embedded devices. Using these tools also gives us automatic document control, a required element of a quality system.
Unless designing for Formula 1 racing there is a trade-off between the effort put into optimising a design (for cost, performance, weight) and the gains to be made. Where appropriate we have the means for detailed optimisation (e.g. Finite Element Analysis for mechanical, fluidic or thermal properties, or optical simulation for lens systems).