The classical Seven Wastes in manufacturing processes are Overproduction, Waiting, Inventory, Motion. Overprocessing, Defects and Transportation. There is an eighth waste which is often added: Unused Employee Creativity.
The need to transport goods incurs cost and delay. To dilute transportation costs, products are often moved in batches, increasing inventory. Uncertainties inherent in transportation give rise to buffering to protect downstream processes, further increasing inventory.
Excess raw material, work in progress or finished goods causes longer lead times, risk of obsolescence or damage and incurs transportation and storage costs. Excess inventory also hides problems such as production imbalance, late deliveries from suppliers, machine downtime, defects and excessive set-up times.
Avoidable motion wastes time. Frequency of repetition determines how much effort should be made to eliminate movement. Examples include repair technicians having to visit stores to draw tools or spare parts, or process operators having to move away from their workstations to collect components. Within a workstation, tools which are inefficiently located or stored require waste of motion to use them.
Any material waiting to be worked on or a resource waiting for work is a waste. The time lost can never be recovered. Operators minding a machine are waiting for it to complete - they could be doing something in the interim. Operators queuing for tools or parts are havig their time wasted.
Making products to a higher specification than required by the customer, using unnecessarily complex processes to deliver a product or service, or processing inefficiently due to poor tool or product design.
Making too much or too early is the most serious waste as it results in several other wastes. The time spent making a product or delivering a service which is not needed, or not needed yet, could have been spent making something which is needed. In addition, transport and storage of excess product incurs cost and working capital is tied up in the unsold product.
Defects waste the resources and materials used to produce them and may incur further waste in their disposal. Rework increases costs and diverts resources.
Unused Employee Creativity
Losing time, skills, improvements and learning opportunities by not engaging with or listening to your employees.
To help remember the original seven Manufacturing Wastes, use the mnemonic TIMWOOD: