Waste analysis is the process of identify waste in a process with the aim to remove them. To eliminate waste, it is important to understand what waste is and where it is. The Seven Wastes, a concept from Lean Manufacturing, provides a systematic way to identify wastes. It categorises wastes into 7 types and for each of them, there is a strategy to reduce or eliminate it.
Overproduction is to produce something before it is needed. This creates unnecessary iinventory resulting in high storage cost and run the risk of product obsolescence. In addition, it slows down the time to detect a defect and when detected, a lot of defects has been made.
Waiting is when the product is not being processed. Typically, in a batch-and-queue process or a process with backlogs experience high amount of waste due to waiting. This results in llonger lead time and if it happens to a bottleneck process or step, it is time lost to the overall output.
Transportation is to move a product between processes or to another location which does not add value to the product. This results in additional transportation cost, equipment cost, and increases opportunity for damage during movement.
4. Over Processing
Over processing is doing work on a product more than necessary to achieve the same result. Examples are such as using expensive high precision equipment where simpler tools would be sufficient, performing safety checks or repeated checks when they are not necessary.
5. Excess Inventory
Inventory or work-in-progress (WIP) is a result of overproduction and waiting. They result in llonger lead times, need for larger storage space, delays the identification of defects and prevents smooth flow of materials and information.
6. Unnecessary Motion
Motion refers to the movement of the operators such as reaching, walking, lifting, etc. Excessive motion has a negative impact on productivity and also health and safety issues.
Defects are the most direct form of waste. Defects have a direct impact on bottom line and also result in associated costs such as rework, inspection, improvement work, etc.