We have recently attended to the irreversible development
of computers, that now are cheaper, more friendly and,
consequently, more diffused in modern industries. Computers
have been used in the industry sector for several years in
different stages: in the design stage Ð using CAD systems;
in the process planning stageÐusing CAPP systems; in the
production stage Ð using CAM systems.
Since a few years ago, these three stages were isolated one
by another and each stage should have answered speci®c
problems and questions. Sometimes it happened that the
production stage imposed some essential conditions to the
other stages (as an example, when the designer establishes
the tolerance for the piece; or when it is necessary to make
some change to the piece during the production stage since
there is an impossible or dif®cult machine production), but
the three stages were strictly separated.
Moreover, it was thought that it was impossible for
different programs, written by different programmers with
different ``logics'', to ``speak'' to each other. Recently,
different programs tried to communicate in order to solve
some problems, but this is very dif®cult to be achieved.
There exist a number of programs which are able to
perform that way, but they are not ``universal'' programs:
they are very specialized programs which can be used only
in speci®c ®elds using powerful computers. As a matter of
fact, it is necessary to develop a universal software easy to be
used by a simple, common and very cheap PC.
Numerical Control machines are very commonly used for
their ability to help industries to achieve an increase in
productivity and in quality at the lowest costs. As a matter of
fact, NC machines are faster and more precise than traditional
ones and they work very accurate surfaces, but are
more expensive and it is more dif®cult to use them than the
traditional ones.
Moreover, it is necessary to compile a speci®c program to
be read by the machine control unit in order to obtain the
data needed to exactly move the tool. This program (called
``part program'') is written using a particular programming
language that can be read by every NC machine (machines
have to be similar: turning machines, end milling machines,
etc.).
The ®rst problem we meet using NC machines is that
when the programmer makes a mistake in writing the part
program, the piece will not be realized the way we want, but
it will have a different shape or different features. But it
could be more dangerous (and also expensive) if the programming
mistake gives the tool a motion command that can
generate a collision between the tool and the ®xed parts of
the machine, because of the speed of the NC machine tool is
higher than that of the traditional machine tool.
We have other problems using NC machines, for example
how to choose the right depth or feed rate or how to choose
the shape of the workpiece in order to minimize the material
waste. As a rule, in order to solve these problems some
cutting tests are realized, but they are very expensive to be
implemented since they are a waste of human resources,
time, materials and money.
Moreover, not all the problems are very easy to be solved
by implementing one test only, so that the test has to be made
again over and over. It should be really useful to make
``virtual'' cutting tests using computers instead of NC
machines and as much useful should be the possibility to