How far is it possible to minimize the waste of materials and reduce the number of processes while improving product functionality?
Making use of materials to the greatest extent possible and reducing the number of processes as much as possible are both important elements in reducing the environmental burden in the production sector. Optimization of materials and their processing not only directly reduces the environmental burden, but also results in cost improvements. This concept is consistent with both the Sustainable Zoom-Zoom, which commits Mazda to "provide all customers who purchase Mazda vehicles with driving pleasure as well as outstanding environmental and safety performance," and the objectives of SKYACTIV TECHNOLOGY.
Yasuhiro Onji, Takashi Ogawa, and Kenji Sato of the Production Engineering Division are engaged in optimizing structures and processes for parts produced in-house. They commented on the process of taking existing concepts in the production sector right back to zero during the creation of SKYACTIV TECHNOLOGY, saying, "It was natural for us to focus not only on parts manufactured by Mazda itself but also those purchased from other companies, which account for around 80% of vehicle manufacturing costs."
Previously, with externally sourced parts, with the exception of a few areas, Mazda was responsible for only "product design," specifying the function of products, while "process design," taking account of efficient production methods, was left to suppliers. "We began to think that if we considered product design and process design together rather than separately, we should be able to combine sophisticated functionality and efficient production lines at a higher level." They worked toward collective planning of structures and processes by considering optimum processes in cooperation with suppliers. A definition was created for this new concept: "physical quantity," referring to the improvement of product functions and minimization of materials and processes while taking cost into account. This approach was also adopted in the press and assembly lines, with the aim of optimizing both structures and processes.
Onji started by extending activities that were already underway in Mazda's in-house press line to outside companies. This involved utilizing computer software to create accurate two-dimensional development diagrams of existing three-dimensional parts, and undertaking an exhaustive analysis of the structure of each part. This study revealed that the die-casting of some parts could be optimized so that excess material, which had formerly been thrown away, could actually be used for casting a second part in the same die.
The combination of several such initiatives has enabled a 13% reduction in the amount of materials required for new sheet metal parts, other than the body sheet metal sector, and the number of processing steps has also decreased by 11% in comparison with previous methods. The engineers offered this knowledge, obtained in-house, to suppliers, and requested their cooperation.
However, the road to innovation was anything but smooth. "When we offered suppliers new production methods, they didn't always accept them without some initial resistance," recollects Sato. "Thinking that the best way to gain their understanding was to show them in ways that were understandable at a glance, we carried out quantitative analyses of factors such as reductions in waste material rates and converted these to numerical values, and showed them computer simulations of the new production methods. We kept going with persistent negotiations until they were convinced."
Ogawa, too, notes that, "Suppliers felt there was a risk involved in changing their current way of doing things, so at times we really struggled to gain their understanding of the type of innovation we were aiming for, and to persuade them to work together with us to implement it." At such times, he would repeatedly question himself, "How should things really be? What do I really want to do?" With a refreshing smile, he confided, "If I wasn't completely convinced of the answers myself, I wouldn't have been able to convince our suppliers. Thinking things through exhaustively became second nature, and led to my own personal growth, too."
"With these conflicting opinions between us and our suppliers, searching for the best methods was hardly easy," adds Onji. "The difficulties we faced in this process, however, honed our own knowledge."
They met suppliers day after day, talking with them, sometimes arguing with them. What they gained from this was more than just "efficiency;" through this communication, they and suppliers arrived at a shared perception. What had previously been a one-way flow of information became two-way, laying the foundations for a PDCA cycle aiming for optimization at a higher level. In this process, suppliers also came to share Mazda's vision, in a step forward toward the attainment of "One Mazda" in a wider sense.
"We believe this initiative is one form of 'innovation' that will enable Mazda to continue to offer our customers Sustainable Zoom-Zoom." The hearts of these three engineers are filled with the desire to continue to offer customers "driving pleasure" and "outstanding environmental and safety performance."