Development of the Furukawa Digital Assembly System to Support
the Design of Wire Harnesses for Automobiles
by Kazuhisa Asai * , Yuuki Obata * , Ayako Naiki * 2 , Yoshitaka Sasaki * 2 ,Yutaka Matsuda * 3 and Kazushi Terasawa * 3

We have developed the Furukawa Digital Assembly (DA) system to support thedesign of automobile wire harnesses (HIT system and FDA system). The DA
system enables a great reduction in manhours for design, number of prototypes, and manhours
for production preparation by utilizing 3D-CAD information from client automobile manufacturers
linked to our present wire harness production design system. The key features are: (1)automatic determination of the branching direction on the assembly and/or jig board, hereinafterreferred to as the production board and of the fitting direction of parts in the application ofstrain analysis technology; (2) layout support adjusted to the size of the production board;(3) examination of production board workability; (4) examination of operational workability;(5) productivity validation of the wire harness production line (process design); and (6)configuration calculation of the fitting condition of the wire harness to the vehicle.

ABSTRACT1.

INTRODUCTION

Three-dimensional design using 3D-CAD has become
established over the last decade in the automobileindustry. In the design of wire harnesses, which areprimary automotive components, a rough configuration isdetermined from 3D data for the vehicle as well. However,wire harnesses are manufactured flat, as they are rather
flexible. Accordingly, automobile manufacturers have
employed two-dimensional 2D drawings using 2D CAD
for wire harness design. Recently, however, automobile
manufacturers are aiming at shorter development times
in order to respond promptly to market needs, and they
have a strong desire that suppliers provide early design
examination.
In response to this, we have sought for greater
efficiency, and upgraded in the application of strain
analysis to part of the harness design work in the form ofa 3D-to-2D conversion HIT System. In addition to a 3D-to2D conversion capability, the present HIT system makes
it possible to calculate the fitting configuration of the wire
harness to the vehicle, and to examine each conditionof the harness, both at production and when fitted to thevehicle.

The other development for the purpose of checking theproduction process is the FDA system, which enables
examination of production board workability, operations,and process design.
We have built a system that supports and examines
the operation promptly in a series of designs, with full
utilization of simulation technology by linking the HIT
system, CAD system, wire harness production design
system and FDA system. This series of systems is called
the DA Circle (Figure 1) and the whole system is known
as the Furukawa DA System.

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* Furukawa Automotive Parts* 2 Furukawa Information Technology* 3 Automotive Products Division��� ������Figure 1����������������DA circle.

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Development of the Furukawa Digital Assembly System to Support the Design of Wire Harnesses for Automobiles

2.

FURUKAWA DA SYSTEMThe Furukawa DA system consists of the HIT System,
Production design CAD system, and FDA system.
In the HIT system, which stands for harness informationtranslation system, the configuration is converted in theprocess between the condition of the wire harness in thevehicle (3D configuration) and the condition at production(2D configuration), and calculation of the stress
distribution of bending and distortion is performed under
production requirements (3D-to-2D conversion and layout
support on the production board (assembly drawing)
and under fixture conditions (2D-to-3D conversion). The
production design CAD system is capable of preparing
for quotations and other form evolution, which require
information output.
The FDA system, which stands for Furukawa digitalassembly system, enables simulation of production board
workability, operations and process design.
The following is an outline of procedures for the designof a wire harness.
1) The designer first converts a 3D wire harness
configuration to a flat 2D configuration using the HIT
system’s 3D-to-2D conversion.
2) He draws a rough layout of the wire harness
configuration on the production board using theproduction board design drawing (assembly drawing)layout support capability of the HIT System.
3) He designs details on the production board using
the production design CAD system.
4) He initiates automatic drawing of a model on theproduction board and examines production feasibility
and wire harness fitting.
5) He simulates production operation using a humanmodel by using the FDA system’s workability check.
6) He optimizes process design using the FDA system’s
process design check.
7) He converts 2D data for the wire harness product to3D data to be fitted to the vehicle (for the use of theproduct), and compares and examines the design
configuration data from the client using the HIT
system’s 2D-to-3D conversion.
In case of trouble in the process of the production
board workability examination or workability check using
the FDA system, or of 2D-to-3D conversion using the HITsystem, the designer goes back to the production design
CAD system and re-examines the production board
design.
The series of operations described above enables athorough examination of both the production feasibilityof the wire harness and the workability of the vehicle
configuration.
2.1 HIT System 3D-to-2D Conversion
The designer converts 3D data for the wire harness as abeam model into 2D data in the application of the finite
element method under conditions of minimum strain. Thissystem enables automatic calculation of the branchingdirection and the fitting angle to vehicle.

Figure 2

Typical layout support for a production board
design drawing (assembly drawing).

Figure 3

2D-to-3D conversion (superimposed images).

2.2 HIT System Assembly Drawing Layout Support
The designer lays the harness out on the actual
production board, incorporating production requirements
based on the results of 3D-to-2D data conversion and
2D design data from the client automobile manufacturer.
Since not all the requirements can be fully incorporated
at this stage, the designer needs to confirm andedit. However, the new system allows layout to beaccomplished without using CAD, providing a userfriendly environment.
Figure 2 shows a typical layout.
2.3 HIT System 2D-to-3D Conversion
The method is analogous to 3D-to-2D conversion. Usingthe 2D configuration of the wire harness as a beammodel, the system calculates the configuration of theharness to be fitted to the vehicle, applying the finite
element method under the constrained conditions ofposition and orientation of the parts to be fixed to thevehicle.
Figure 3 shows the results restored by 2D-to-3D
conversion, superimposed on the harness center line
(blue line) of the design data, which are provided bythe automobile manufacturer. This makes it possible topresent the client manufacturer not only with a fitting
configuration of improved accuracy, but also with more
realistic results by providing additional information(testing function).
As Figure 4 shows, wire distortion is visualized and thereaction force is displayed from fixed components andthe elongation by conversion data.

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Development of the Furukawa Digital Assembly System to Support the Design of Wire Harnesses for Automobiles������������� �� ���� ������������ ���������� �� �������� ��������� ����������Figure 4������� ������������ �������������� �����2D-to-3D conversion(evaluation function displayed).
Figure 5

2.4

FDA System Workability Examination onProduction Board
This is a system that speeds up solutions to the past
problem that data extraction was only possible in theproduction process using a 3D model. This system isa customized ENVISION 3D simulation system madeby Delmia of U.S.A. Regarding its capability to validate
workability on the production board, it automatically
produces a 3D production model on the production
board, validates the feasibility of actual production bychecking interference, based on data on production
board design developed by the production design CADsystem.
In wire harness production, it is sometimes necessary
to make harness products with different specifications
on the same production board, thereby necessitatinginterference checking utilizing a jig, etc. This isfollowed by examination of the responsiveness to all
the production set for the production board. This is thesame as the case of operating jigs in the wire harness
production process.
Figure 5 shows an example of examination ofworkability on the production board.
2.5 FDA System Workability Examination
Regarding the system’s validating function, the systemvalidates workability in the wire harness production
process on the production board by means of simulation
using an ENVISION/Ergonomics human model adjusted
to the physical build of the operator engaged in harness
production, allowing detailed items on working space andthe operator’s posture to be examined.
Figure 6 shows an example in which tape wrapping is
examined.
2.6 FDA System Process Design Examination
This is a system that speeds up solutions to the past
problem that data extraction was only possible in theproduction process using a 3D model.
The FDA system process examination is carried out
by operating a customized QUEST 3D factory simulation
system made by Delmia together with the ENVISION
3D simulation system. Utilizing validation of production
board workability and operational workability on theproduction board, it identifies the best architecture andConsistency verification for production
board based on FDA system.

Figure 6

Figure 7

Workability verification based on
FDA system.

Process design verification based on
FDA system.

identifies problems on the wire harness production
line, such as optimization of the production line in thedevelopment process, problem finding in line operations,and validation of time allocations.
Figure 7 shows an example of process designverification.

3.

EFFECTAs yet we have few examples of operations using thissystem, so that full-fledged examination of its effect lies inthe future. At present, we expect that the development of
its various functions will produce the following effects:

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Development of the Furukawa Digital Assembly System to Support the Design of Wire Harnesses for Automobiles

1) Effect of using the HIT system’s 3D-to-2D conversion
and production board drawing (assembly drawing)layout support: we expect 70 % reduction in themanhours required for production board drawing(assembly drawing).
2) Effect of using the FDA system workability
examination of the production board: in the past,problems such as jig interference and shortage ofworkspace were not discovered until the prototypesof the production board and harness were actuallybuilt. The FDA system workability examination of theproduction board has made it possible to discoverthese problems without prototypes of the production
board. This is a great advantage.
3) Effect of using the FDA system workability
examination: as in 2) above, the workspace andworkload can be examined without a prototype. A
reduction in learning time can also be expected, as
the production procedures can be visualized and areeasy to learn.
4) Effect of using the FDA system examination ofprocess design: this is as in 2) above regarding
productivity of the whole production line (processdesign). It has been possible to support achieving
the best line architecture and identifying problems
without building a prototype. Also, as in 3), a
reduction in learning time can be expected byutilizing it as operational instructions.
5) Effect of using the HIT system’s 2D-to-3D
conversion: in the past it was necessary to fit awire harness prototype to a vehicle or vehicle
simulator to examine the condition of fitting to thevehicle. Because trial fitting is very costly, as are
the wire harness prototypes, the client automobile
manufacturers are eager to reduce the number ofprototypes required.
This system is not only for internal use by Furukawa,but is also useful as a solution for client manufacturers’
desire to reduce the number of prototypes.

4.

REFERENCE
1) “Toyota Production Engineering Department Fully Utilizes 3DModel,” Nikkei Digital Engineering, Nov. 1999. (in Japanese)
2) “Toyota Decides on Implementation of CATIA V5,” “Pursuit ofToyota Production Method is the Same as IT Utilization,” Nikkei
Digital Engineering, May. 2002. (in Japanese)3) Delmia Japan User Conference 2000
http://nde.nikkeibp.co.jp/emc/pdf/pdf04.pdf
4) “Development of Furukawa DA System Supporting Automobile
Wire Harness Design,” Furukawa Information Technology Co., Ltd.
15th Anniversary Technical Articles. (in Japanese)

FUTURE DEVELOPMENT

The main issue for the future is to accumulate data
through actual operations and fine-tune the system forfurther efficiency.
Among our challenges in terms of system development
are:• Improvement in 2D-to-3D conversion accuracy;• Tracking the effect of layout on the production board;• Improvement in production simulation accuracy;• Expansion of production simulation coverage;• Responding to new CAD systems of client
automobile manufacturers;• Promoting automation; and• Involvement in design/production know-how.
We are committed to finding solutions to the aboveproblems, as well as to reconfiguring the CAD systems ofclient automobile manufacturers.

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