Introduction to Modern Product Development - Advanced Design and Manufacturing Technologies for Biomedical Devices - page 12

• Level “A” prototypes (commonly called “A-samples”). These are demonstration
prototypes for analysing shapes, geometries and other more subjective aspects
(like aesthetics, visual impact or ergonomics) related to the product under
development.
• Level “B” prototypes (commonly called “B-samples”). These are functional pro-
totypes intended for checking the behaviour of different product parts and their
functionalities. Although they are generally made of nonfi nal materials, these
tests are usually performed with limits on certain applications.
• Level “C” prototypes (commonly called “C-samples”). These are prototypes
with similar materials and behaviour to the end product although the manufactur-
ing methods used to obtain them do not coincide with the methods used in pro-
duction. These level “C” prototypes are usually manufactured for fi nal checks, to
prepare production start-up and for obtaining offi cial approval as part of the
detailed engineering stage which will be dealt with further on.
However, the end of the basic engineering stage and the beginning of the detailed
engineering stage cannot be precisely delimited as there is always some overlap that
is to the benefi t of the overall process.
Detailed Engineering . Once the fi nal basic design has been obtained, work must be
begun on the requirements of the shape, properties, size and tolerances of the differ-
ent parts. The fi nal choice of manufacturing and assembly must also be done as well
as fi nal cost evaluation. The outcome of this stage is the defi nitive technical specifi -
cations of the product: a list of functionalities, production plans and the specifi ca-
tions including the instructions for assembly, disassembly and operation. Based on
this information or technical documentation, production start-up can be undertaken
as well as the placing of the product on the market. According to the above, detailed
engineering work can be divided into the following:
• Finalising the end design - The different parts are fully defi ned by means of
plans or 3D geometry CAD fi les, and materials, tolerances, adjustments and
other details are specifi ed.
• Parts integration - By means of full comprehensive plans or CAD assembly fi les
which defi ne the product as a whole.
• Finalising paperwork - For an unambiguous defi nition of the product and be able
to launch production.
• Final checks - As to compliance with general regulations and company stan-
dards. Precision of size and tolerances, the availability of standard or catalogue
parts and other checks.
The basic and detailed engineering stages can often be brought together in one
single-design stage with a global focus where the level of detail is gradually added.
The ever more generalised use of CAD-CAE-CAM technologies and the already
mentioned PLM tools has promoted this gradual fusion between stages, which also
simplifi es any information exchange between the agents involved in product design.
Other authors with a similar outlook to that set out (Roozenburg and Eeckels 1995 )
also include production and marketing planning actions in the methodology they