Computer Aided Progressive Die Design

COMPUTER AIDED PROGRESSIVE DIE DESIGN
SEUI NAKAHARA, TOSHIO KOJIMA, KIMIO TAMURA, FUMIO ASUKE,

CHOICHIRO SODA and TATSUYA NAKAMURA
Mechanical Engineering Laboratory, Japan
SUMMARY
The MEL system which offers advantages in improving the design process
is described. Our system consists of ten steps. Each step can be used in-
dependently of the others. This method enables us to design a new die, and,
in addition, changes and corrections of part of an existing die can be done
easily. In our system, a product shape is input hierarchically using ele-
ments such as points, lines, and circles, closed figures consisting of these
elements, patterns consisting of these closed figures, and the product con-
sisting of these patterns. We introduce a concept of the basic pattern
which corresponds to the shape of a standard punch. There are several of
these. These patterns can be input efficiently using the macro commands for
the pattern in the hierarchy, hence input is simple and the programming can
be done quickly. The great benifits accrue from these patterns, i.e., the
most effective blank and strip layout including information of the tool con-
figuration can be done quickly.
INTRODUCTION SYSTEM FORiviULATION
In the field of die design, the need Characteristics of Press Tool Design
for computerization has become strong re-
cently. This arises from the fact that the In this project, we did a survey of the
demand for dies is increasing as press pro- design method through interviews and dis-
duction has come to rather smaller quantity cussions with people who were doing real die
production than before. And on the other designs <5>. By this investigation, their
hand, since dies themselves are becoming knowhow and technical data could be filed.
high-graded and complex, there are diffi- Some features of die design are the follow-
culties in satisfying the increasing demands ing.
by the conventional ways of design. Never- (1) Almost all information essential to
theless there may be relatively a few groups design is known to the designers through
developing a computer aided die design their experience. It needs skilled and
system. Two main reasons are the following: artistic techniques of skilled engineers.
one is that it can be done fully through (2) Often, blanking products are very simi-
high level techniques and the experience of lar. In these cases, the die structure is
skilled engineers, and that it is difficult very similar and can be done by some modifi-
to program their knowhow and technical data; cations to the drawings.
the other is that to find economical merits (3) In press manufacturing, press tools
by the introduction of computers to this (punch and die) correspond one to one to
field is difficult as the die is a very blanking; they are closely related and at
custom made product (it is rare to make least some parts of the edge shape of a
exactly the same two dies). Several works punch is retained somewhere in the product.
have been reported, but those relying on (In metal cutting, a cutting tool can make
the standardization of components <l> are various shapes and there is no geometric
not sufficiently suitqble for the computeri- relation between them.)
zation of the whole design process, and (4) Large part of the total design hours
those on the computer side <2>, <3> and <4> are spent in making drawings.
have not fully investigated its design So, making a CAD system cannot be done
characteristics. by the direct conversion of the conventional
One objective of this project is to design process to computer programs, but by
make clear a standard design technique and rearranging it, standardizing the components
to reduce the designing hours to some extent largely, and re-formulating it as a set of
by realizing a practical computer aided die numerical technical data and a standard set
design system. This paper is concerned with of design operations.
the two dimensional progressive die, which Following points are considered in the
is rather complex and becoming popular, and system design.
discusses some geometric and technical (1) Interactive system using a g~aphic
characteristics of the design and the CAD display device: die design accompanies
system. comparatively complex graphic procedures
and this is a practical and efficient way
as the design process is classified into
the portion that relies on the designers'
examination and decision, and the portion
171
B. J. Davies (ed.), Proceedings of the Nineteenth International Machine Tool Design and Research Conference
© Department of Mechanical Engineering, University of Manchester Institute of Science and Technology 1979
172 COMPUTER AIDED PROGRESSIVE DIE DESIGN
that can be done automatically. (5) Standardization of die components, die

(2) To establish each design stage (here- structure, and machining of dies: the struc-
after we call this a step) and to decide ture of dies as well as some components from
its input information, data, CRT operation, punches to bolts and springs is becoming
and output: it is essential to decompose standardized and some are coming widely in
the whole complicated process into some the market.
relatively separate (not so much inter-
connected) steps and to make clear their MEL System
interconnections and their required infor-
mation. The CAD system developed at Mechanical
(3) To use some steps individually: as Engineering Laboratory follows the design
stated above, it is rather often required policy described above and is structured as
to modify some parts of the design done shown in Fig. 1. It has the INPUT step
before, and the system can also be used in shown at the leftmost column and nine other
these cases. steps in the third column. The flow of
(4) Ease of handling the data and the pro- input information and data items in the
grams required in each step: in the course database, as well as the design results in
of the design, to register a new program as each step which are required in another
a design operation and/or to store some step, are shown by arrows. First, a user
technical data including the design results inputs the shape of a product as a set
up to that time, can be done easily, as operation of patterns (which are described
engineers possess knowhow from their ex- later).as well as other specifications such
perience. as burred side, tolerances, material, its
CONTROL AND MONITOR
SPECIFICATION CHECK LIST OF

OF PRODUCT PRESS WORKING
PRESS MACHINE
DIE MAKING DRAWING

EQUIPMENT
DRAWING
FORCE I
---+-~COST
SHIPPING LIMIT
ASSEMBLY DRAWING
DETAIL DRAWING
ILLUS'l'RATION &
Fig. 1 Design Steps LIST OF PARTS

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COMPUTER AIDED PROGRESSIVE DIE DESIGN

SEUI NAKAHARA, TOSHIO KOJIMA, KIMIO TAMURA, FUMIO ASUKE,

INTRODUCTION SYSTEM FORiviULATION

that can be done automatically. (5) Standardization of die components, die

CONTROL AND MONITOR

SPECIFICATION CHECK LIST OF

DIE MAKING DRAWING

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