Improving efficiencies by eliminating waste is often the most effective way to boost the profitability of a business. Toyota’s Chief Engineer, Taiichi Ohno designed and developed ‘The Seven Wastes’: a tool that is used in lean manufacturing to identify and categorise the waste generated from a process. By identifying and categorising this waste, it makes it possible to improve efficiencies across many different aspects of the production line. Generally speaking, the 7 wastes in lean manufacturing apply to all manufacturing environments making it simple to apply this tool to many applications.

The Seven Wastes in Lean Manufacturing are:

1.Overproduction.

Manufacturing a product that is not required to satisfy the current level of demand is classed as overproduction. This type of manufacturing is extremely expensive as it results in high storage costs and a lower quality product. By manufacturing products as and when they are required (also known as Toyota’s “Just in Time” strategy), it is possible to eliminate storage costs and improve product quality. To achieve this waste elimination, products must be available to ship immediately once manufactured, and machinery changeover time must be minimised.

2.Waiting

In traditional batch-and-queue manufacturing, over 99% of a product’s life will be spent “waiting”. Goldratt’s theory of constraints suggests that "a chain is no stronger than its weakest link" and therefore the overall factory’s output is reduced by as much time as there is time spent waiting.

3.Transporting

The transport of a product between processes adds zero value to the product; however it does incur a cost. Minimising the length of transport will reduce cost while also improving overall quality of the product as the risk of damage from handling is also reduced.

4.Inappropriate Processing

Overestimating the required tools for processing a product leads to waste and is often analogised as “using a sledgehammer to crack a nut”. By using equipment that is suited to each role the manufacturing process can be improved. Replacing expensive and over-able machines with simpler tools that can perform the same task removes this waste in lean manufacturing.

5.Unnecessary Inventory

An excessive inventory is a direct result of wasteful processes such as overproduction and waiting. An excessive inventory is indicative of waste problems that are occurring elsewhere in the factory. This waste category can be incredibly expensive as an excessive inventory takes up valuable floor space and inhibits communication.

6.Excess Motion

Human efficiencies are also very important in lean manufacturing. All production plants must consider healthy and productive ergonomics if they wish to reduce the manufacturing waste caused by poor health. Areas of work that require walking, lifting and other potentially strenuous movements must be analysed carefully to uncover areas of improvement in human efficiencies through ergonomics.

7.Defects

Defects can be hugely costly for many organisations. This type of waste directly affects a company’s net income and is often a significant part of total manufacturing cost. Defects can result in the recall of products, quarantining of inventory and capacity loss. One technique to reduce the chance of defects during production is through Continuous Process Improvement.