Intelligent Lean Manufacturing: Lean Manufacturing, Lean Transformation, and Digital Transformation Relationship Evolution

1. Introduction

Increasing and decreasing customer demands from the market, which also require a wide variety, are balanced with the competencies of the manufacturer and its suppliers. In this context, the capacities of the workstations and consequently of the production lines have gained more importance. In order to increase the performance of workstations, to increase their availability and to produce quality products, the queue, transportation, waiting, preparation and operation of five parameters, respectively, related to the operation supply period, namely the capacity, came to the fore in the production process. After World War II, Eiji Toyoda and Taiichi Ohno came up with the idea of lean production, which will spread to industrialized and developing countries in the process from the mid-twentieth century to the present. The most important reason for the development of this approach was the habit of working with overstocks, which caused excessive losses, especially in the automotive industry, which makes mass production.

For the effective implementation of the lean manufacturing approach, it has been thought to create a healthy infrastructure with a human-oriented total quality management (TPM) and continuous improvement approach (Kaizen). TPS from the Japanese auto industry consists of several interlocking applications that provide superior performance. These include two important umbrella concepts namely just-in-time (JIT) delivery of parts, Jidoka (the practice of stopping the line when defects are uncovered) (Adler and Borys, 1996; Pil and Fujimoto, 2007; Spear and Bowen, 1999). Along with these two concepts, the following has also been used. These are respectively leveling of production volume and product mix (heijunka); reduction of ‘‘muda’’ (non-value adding activities), ‘‘mura’’ (uneven pace of production) and ‘‘muri’’ (excessive workload); production plans based on dealers’ order volume (genryo seisan); on-the-spot inspection by direct workers (tsukurikomi); fool-proof prevention of defects (poka-yoke); real-time feedback of production troubles (andon); assembly line stop cord; Gemba Walks to ask questions to machine operators to see the actual process of production;.value stream mapping (VSM); emphasis on cleanliness, order, and discipline on the shop floor (5-S); total productive maintenance (TPM) applications to ensure worker participation in preventive maintenance and reduce machine downtime or stop; use of Single minute exchange of dies (SMED) to reduce set-up, calibration, set-up times for die change, as well as to reduce inter-station times in the production line; Pulling systems (KANBAN) used to control production resources and prevent unnecessary stock holding in accordance with the just-in-time approach in production and so on.

Sugimori et al. (Sugimori et al., 1977) pointed out that one of the pillars of the Toyota production system is making the most of the working environment and excellent employees in production. In this context, it is encouraged by the workers to eliminate their unnecessary movements, to take into account the safety of the workers, to show their skills by giving more responsibility and authority to the workers by rewarding them.

According to reputable scientists who have demonstrated the relationship between the human factor and lean production very well, the importance of the employee within the organization has been emphasized in order to improve production. Accordingly, sharing responsibilities with employees, teamwork, and employee participation in continuous improvement are essential for the success of lean manufacturing (Cooney, 2002; Jones, 1992).