Many companies in Japan engage in high-mix low-volume production, and the current situation is that much time is devoted to changeovers in high-mix low-volume production. Therefore, situations easily arise where operating time is also lost. As an important item at production sites, many companies are working daily to improve changeover time, aren't they?
In changeover work, it is important to review time reduction in the task of preparing components. This time, we will provide detailed explanations from the basic mechanisms of changeover to methods for reducing changeover time and proposals for beneficial inventory management systems.
・Understanding the Basics of Changeover
・Reasons Why Changeover is Necessary
・Problems in Changeover
・What Can Be Done for Time Reduction
・What is the Most Efficient Time Reduction Method?
・Summary
JJIS Z 8141 defines setup as "preparation of materials, machines, jigs and tools, drawings, etc., and trial processing before starting work." At production sites, changeovers are performed to set up and modify equipment according to product specifications. There are two types of changeover: external setup and internal setup, and internal setup is a particularly required point for improvement from a time perspective.
In the process of lot production, when executing model changeover, it is necessary to perform preparations such as equipment settings and modifications, and this preparatory work is called changeover. Mold replacement work and equipment cleaning work fall under this changeover. Additionally, the period from the completion of product processing to the next changeover until reaching a state where production is possible is called changeover time.
Changeover work executed outside the equipment while the production equipment is operating is called external setup. Tool preparation, material transportation, and cleanup fall under external setup. Because production activities can be maintained during changeover work, it does not affect equipment utilization rates.
Changeover work executed on the equipment while the production equipment is stopped is called internal setup. Component replacement and confirmation work are performed while the equipment is stopped, but because production activities are not possible during work, the utilization rate decreases.
When the utilization rate decreases, it directly affects productivity.
From the perspective of production efficiency, the time required for changeover needs to be reduced, and reduction of man-hours is essential. If time can be reduced, it contributes to improvement and enhancement of production efficiency in work processes, as well as reduction of worker burden and maintenance and improvement of motivation.
With large lots, the number of changeovers can be reduced and production efficiency can be improved. However, production lead times may become longer, and work-in-process and semi-finished products may increase. Additionally, excess work-in-process brings increased cash outflow. With small lots, production lead times become shorter and work-in-process decreases, but changeovers occur frequently and production efficiency declines.
To minimize production loss, how much internal setup time can be reduced becomes important.
Additionally, in cases where changeovers are performed multiple times per day, human errors are also a concern.
The same can be said for external setup.
When reducing changeover, it is necessary to focus on improving internal setup rather than external setup. Ultimately, by reducing both times, it leads to production efficiency. The method for performing changeover requires following the four steps below.
Information is collected from a broad perspective on problem items in external setup and internal setup, and the current situation is understood to improve them. For example, changeover time within working hours and specific work processes are summarized, and problem points are listed for each series of processes and machines.
After that, classification into internal setup and external setup is performed.
A series of work processes and problem points for each machine are classified into internal setup and external setup.
Tasks that can be executed as external setup are performed in advance. This refers to converting all preparatory tasks that can be prepared in advance, such as mold preparation work and processed product transportation that occur in internal setup, to external setup. By executing this, the time required for internal setup is reduced.
A series of tasks related to installation, replacement, and removal are simplified, and adjustment work is reduced or eliminated. For example, installation and removal of jigs and tools, elimination of mold fixing screws, and elimination of adjustment work are applicable.
Additionally, work is basically advanced in parallel, and by establishing rules for these, reduction of internal setup time is aimed for.
Similar to internal setup, rules are established, and reduction of external setup time is aimed for through thorough 5S implementation, work training, manual formulation, and regular effectiveness measurement.
Furthermore, when you want to realize man-hour reduction quickly and accurately, an inventory management system is implemented. Introduction of a specific inventory management system will be explained in the next section.
While reducing time, maintaining a consistently error-free situation is very important when performing changeovers. For changeover work that repeatedly receives and issues inventory, the Smart Reel Rack, which contributes to streamlining company operations as an inventory management system, is optimal.
The Smart Reel Rack is an inventory management system that digitizes electronic component reel storage shelves and can significantly improve work efficiency on production lines. By utilizing this system, necessary components can be instantly found through LED lighting instructions, and receiving/issuing time can be reduced and human errors can also be prevented. From this content, the Smart Reel Rack has been adopted by a great many companies in recent years as the most efficient changeover time reduction method.
Please view the dedicated Smart Reel Rack page here.
You may think that changeover is inherently a time-consuming task, but by introducing the inventory management system described above, it can be transformed into a process that achieves significant time reductions.
As companies review their operations to shorten setup time, the number of organizations adopting this system continues to grow day by day.
Customer needs and demands will become even more diversified going forward, and we are entering an era where speed is increasingly required.
To survive the turbulent times ahead, the introduction of this system is considered essential.