Human actions (movements) involved in producing products. These actions can be divided into three categories:
1. Value-creating: work directly necessary for making products, such as welding, drilling and painting.
2. Ancillary work: work that operators must perform to make products but that does not create value from the customer's point of view, such as reaching for a tool or clamping a holder.
3. Waste: work that does not create value and could be omitted, such as walking to retrieve tools or parts that could be placed within easy reach.