Page 152 - Modular design for machine tools

112 Modular Design Guide and Machine Tools Description

need to develop the system description including the description for
the system machine.
In retrospect, a crucial problem was to find some compromise solutions
with respect to, e.g., the shapes and sizes of modules from the viewpoint
of the casting pattern as well as the allocation of slideways and location
faces in consideration of machining in the mid-1970s. At that time, the
designer must be qualified for seeking the compromise solution with her
or his high abilities and skills. As will be discussed later, the machine
tool description may furthermore add something definite to this prob-
lem, and that of Redeker and Saljé is associated with it.
To summarize, the methodology for the modular design must, as men-
tioned above, deal with several issues related to three of the four princi-
ples of modular design, especially emphasizing the principle of adaptation.
This emphasizes directly the fast-growing importance of the machine
tool description.

3.1 Basic Knowledge about Functional
and Structural Description Methods
It is very interesting that Stau is credited with being the first engineer
to propose the functional description in 1963, although he had no
intention of applying it to modular design. It appears that he tried to
provide a clear idea for a form-generating function in turning [1]. The
description method proposed by Stau is very simple, but its basic idea
has been employed within various functional description methods
developed since then. In his book entitled Die Drehmaschinen, he tried,
as shown in Table 3-1, to classify the form-generating function of the
machine tool by using the symbolic representation and decision table.
Actually, the machining method is classified using the combination of
traveling and rotational movements in both the work and tool
branches.
Intuitively, it is desirable in the machine tool description that the
machine tool be represented using only one method; however, the
machine tool can be represented in various ways, depending upon what
feature is emphasized in the description. At present, there are the two
methods: one is the functional description (movement description) and
the other is the structural description. In a machine as a whole, a one-
to-one relationship between the function and the structural configura-
tion is obviously not guaranteed; and a function can, in general, be
realized by myriad structural configurations, although a structural con-
figuration can provide us with a single form-generating function.
Conceptually, the functional description is in a higher level than the
structural description, resulting in the obvious difference in the descrip-
tion method, difficulties in the description, and application areas, as