PARTICIPATION OF WORKERS
6. JOB DESIGN, MACROERGONOMICS, AND PRODUCTIVITY 127
FIG. 6.1O. Organization of a project team in participatory er
gonomics.
(3) Workplace Survey Activities
The project team determines the mission of the project, such as reducing acci
dents, enhancing product quality and production, or reducing manufacturing cost. With regard to participatory ergonomics, the mission will realize workers' welfare and higher productivity. Solution of the former usually leads to improve
ments in workplace safety, product quality, and productivity as well (Imada &
Nagamachi, 1990). Based on the mission, and with the help of quality circles, the team surveys what is going on in the production lines and collects data about problems. The team analyzes the data in terms of macroergonomics and, where appropriate, statistical methods (e.g., multivariate analysis) to determine the macroergonomic factors affecting the work system.
(4) Ergonomic Strategy for Improving the Lines
The team chooses the ergonomic and organizational strategies to solve the factors hidden in the workplace. The quality circles are used to discuss whether the redesign strategy is the best one or if other approaches can better solve the ergonomic problems. After getting opinions from the quality circles, the project team revises the solution strategy according to macroergonomics.
(5) Ergonomic Review
After the work system redesign is conducted, the team reviews and evaluates the redesigned production lines from the viewpoint of macroergonomics and enterprise strategies. I have obtained good outcomes using participatory er
gonomics and a macroergonomic approach in a number of organizations, includ
ing almost zero-level accidents in many manufacturing companies, and more
than a 50% improvement in productivity (Nagamachi, 1995). An intervention using participatory ergonomics and a macroergonomic approach, conducted in an auto
motive company, Fuji Heavy Industry Company, led to a 200% increase in produc
tivity and achievied a 100% level of passenger car quality (Nagamachi, 1998).
Implementation of Participation in Job Design Activities
Formal participatory ergonomic programs were implemented in the Daikin Com
pany (Nagamachi), Mitsubishi Heavy Industries Company (Nagamachi, 1985, 1991), Nissan Oppama plant and Nissan Diesel Company (Nagamachi, 1993).
Job Redesign in Daikin by Participation
Because it is thought that workplace improvement was important for its workers' welfare, Daikin attempted to implement participatory ergonomics to improve the production lines for air conditioners. The Daikin Kanaoka plant was selected as a model plant for introducing participatory ergonomics, and a project team was established. Nagamachi's working posture measurement was selected as a tool to survey ergonomic problems. A higher workload posture was selected by this analysis and was implemented via micro-ergonomic redesign to reduce postural loading. In the second redesign stage, robots were used in the lines to improve jobs that otherwise were hard to change. This participatory ergonomics effort resulted in a more than 40% increase in productivity due to improved working postures (Nagamachi, 1985).
Change in Production Line in Nissan Diesel
Nissan Diesel is a truck maker that has a strong relationship with Nissan. A 10-ton truck assembly line in the Ageo plant was chosen for introducing partici
patory ergonomics and for realizing work motivation. Because the plant had quality circles, a project team was organized as shown in Fig. 6.10. First, the team surveyed the model line to find the ergonomic problems, and it interviewed the members of quality circles about their awareness of problems happening in the line. About 60 items were listed and categorized as A, B, C, in which A meant easy problems to be solved quickly; B meant problems taking several weeks for solution; and C implied big problems requiring a long time period and large investment to solve. The A problems were solved quickly by the team and the circles. B and C category items were analyzed using participatory ergonom
ics. One of these ergonomic problems, a propeller-shaft mounting task, was selected to be solved with regard to safety workload. A long, heavy shaft used to be attached to an engine by four workers. The assembly work forced the workers to bend their backs under the truck chassis. This work is very dangerous and four workers already had suffered back injury. The manager ordered the production
6. JOB DESIGN, MACROERGONOM1CS, AND PRODUCTIVITY 1 29 technology department to devise a jig that would cause the shaft assembly to be lighter. However, because the workers did not participate in planning the jig, they did not want to use it. After organizing the project team, a design of a sup
porting jig for the propeller-shaft began in the quality circles with the help of the production technology department. Because introducing the new jig was thought to be insufficient to solve the ergonomic problem, the project team discussed a complete change of the truck production line. The team consulted with manage
ment to change the line and decided to use a big machine to reverse the truck frame. As it was reversed, a propeller-shaft was inserted through the frame from the overhang. After this work, the truck frame was returned to the original posi
tion with the propeller-shaft under the chassis. At the assembly line, a worker eas
ily inserted the propeller-shaft to the engine using the new jig devised by the team.
The participation of the workers in redesigning the production line resulted in reduced accidents and increased productivity. The workers were proud of the redesigned production system because of their participation. The project team painted this area purple, so it could be easily noticed as the participation area.
NEW TREND IN PRODUCTION SYSTEMS The Japanese worker's wage is comparatively high. Therefore, Japanese enter
prises attempt to construct factories in Asia, where the workforce is easily hired at low cost. However, after a decade of this overseas cost-reduction strategy, the Japanese noticed that there was not much profit benefit and that there were chronic problems with punctual delivery. Additionally, Japanese workers desired greater satisfaction with their work and self-development through the organization. Re
cently, employers have endeavored to realize benefit for both management and the workers by introducing a work system design called the "cell production system."
Basically, this is the new name for a one-person system described earlier.
For example, NEC Nagano (Nippon Electric Company, Nagano Company) studied the conveyor belt work of ten, five, and three person groups, and a one- person system. Experiments resulted in 150% productivity for the one-person or cell system, as compared with the baseline conveyor belt system (Nagamachi, 1996, 1997, 1998). The cell system implies that a worker assembles the whole product. In NEC Nagano, one worker assembles a whole personal computer. It is named "Yatai," which is something like a hot dog stand. In NEC Nagano, the conveyor lines were removed completely, thereby preventing the managers from returning to conveyor belt production. Many factories now have changed from production lines to the cell system. These companies include NEC Yamagata, Toshiba, Kyushu Matsushita, Alps Electric, Sony, Minolta, and Olympus. The Japanese have sought the highest efficiency of production for a long time, but now they understand the macroergonomic implication that realization of work
ers' motivation leads to organizational advantages as well (Fig. 6.11).
FIG. 6.11. Scene of a "cell production system" at NEC Nagano.
FIG. 6.12. Two-person work system at the Volvo Uddevalla plant.
Volvo in Sweden has conducted an interesting experiment in Uddevalla in which two workers assembled a passenger car together. Ellegard and her col
leagues (Ellegard, Engstrom & Nilsson, 1992) investigated production with terms of 20, 10, 8, 4 and 2 workers. In Uddevalla, two workers brought the parts from the parts yard and assembled a whole car by themselves. Volvo obtained good outcomes from the redesigned production system (Fig. 6.12).
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