Modern manufacturing technologies demand components produced to very narrow
tolerances: the number of non-satisfying parts is nowadays limited to some
tens per million, the final goal being "zero-defect production". In order
to fulfil these preconditions, the forming processes must be well understoo
d and kept under permanent control. The geometrical accuracy of cold-formed
components depends on many parameters, among which the most important are
the incoming material, the machine, the tools, and the process itself.
This paper first discusses some efforts in analysing the impacts of differe
nt process parameters where a combination of experiments and numerical eval
uations was used. The research was oriented towards ranking of the paramete
rs, according to their influence and studying their interrelated effects on
the processes. In the final sections. an interesting phenomenon concerning
the accuracy control were presented: it is possible to find such a combina
tion of parameters where the process is stable, and not so sensitive to the
fluctuations of parameters. The definition of such "stable technological w
indows" will be very valuable for practice, especially for technology plann
ing. (C) 2001 Elsevier Science B.V. All rights reserved.