Downed assembly lines result in lean manufacturing waste.
Various types of lean manufacturing waste include material waste, avoidable downtime, and time lost on unproductive activities. Overproduction is another form of waste. Other types of waste can arise from inaccurately matching resources to tasks or performing unnecessary movements in the workplace.
Manufacturing defects are common means of causing material waste. Sometimes these defects result from machines that have not been properly maintained or used improperly. Another type of lean manufacturing waste can occur during the stages of manufacturing where raw material is molded or cut for a specific purpose. If this process goes wrong due to operator error, often the part must be disposed of as waste.
Lean manufacturing managers may require production workers to learn new skills and approaches to their work.
Planned or unplanned downtime can result in wasted facility usage and labor hours. When an assembly line is idle – due to an equipment failure, for example – underutilization of this resource produces lean manufacturing waste. Typically, unplanned downtime will produce more waste than planned downtime. A common reason cited is lack of time to plan for a controlled interruption of production.
For example, if the assembly line is shut down at a time when all operations have been planned, and materials and people have been positioned to engage in productive work, this event is likely to create a major waste of time. On the other hand, if the outage is planned, production managers will usually see to it that the fewest number of employees remain at the facility during the outage. This pre-planning often reduces payroll costs.
Inaccurately matching resources to tasks is another type of lean manufacturing waste. Sometimes this may involve harnessing the skills of a highly trained person to perform a task that a less trained person could perform. Other times it may involve a mismatch between the equipment and the task. For example, if a worker is trying to complete a task with a machine that is not specifically suited for that task, this can result in wasted time.
Unproductive activities can also involve performing unnecessary tasks and can occur in two ways. First, the person performing the task may be involved in extra moves that are not required to complete the task, and second, the task may not even be part of the planned manufacturing routine that the manufacturer has put in place. For example, if a worker has to transport a certain amount of partially completed materials on a regular basis, he or she may choose to engage another worker in a conversation at another workstation. While it may seem like an almost insignificant factor in lean manufacturing waste, when this activity is repeated multiple times a day or week, the cost of downtime increases.