In the Value Stream Mapping article, it discussed how the Seven Wastes of Lean can assist in the identification of waste. This article will explore this in more detail.
Eliminating waste was the idea of one of the founding fathers of lean manufacturing, Taiichi Ohno.
He identified three major areas that have a negative impact on work processes. One of those, ‘Muda’, groups the wasteful activities that take place. Ohno, divided the types of waste between seven categories, now known as the seven wastes of lean, and a popular practice for reducing costs and optimising resources.
What is Muda?
Waste is described as any activity that uses resources but doesn’t bring any value to the end customer.
During the process however, there may be many areas that don’t add value to your customer but are vital to producing a satisfactory product or service. It is therefore important to note that not all wasteful activities should be eliminated from the process.
Wasteful activities should therefore be split into two categories:
Included in this category are activities that don’t add value to the end customer but are essential in creating a quality product or service. An example of this may be testing software.
If activities don’t add value and are unnecessary then they are classified as pure waste and should be eliminated from the process immediately. An example of pure waste is waiting, of any form.
The Seven Wastes of Lean
The seven wastes of lean identify areas in which Muda activities can be found.
The actual transportation of the product adds no value, and so it is essential to minimise these costs and avoid moving materials or resources unnecessarily. Costs can quickly mount for materials that are moved excessively, and damage quality.
This may be rectified by moving the plant and production chain closer together, or by using more effective transport methods.
Toyota are arguably the most successful proponents of lean manufacturing, and it is easy to see why when you compare their ‘just in time’ method of working to the more common ‘just in case’.
Just in case inventory involves a company overstocking their inventory to meet unexpected demand, or to protect themselves from problems such as production delays or low-quality produce.
Holding excess inventory increases storage and depreciation costs and ties up capital.
Motion covers the wasteful movements of both employees and machinery, which are often complicated and unnecessary.
The process should be arranged so that employees are required to do as little as possible to complete their job. This could include, for example, having materials in an easy to reach place as opposed to an employee having to bend to pick something up.
When a product has been overproduced it has exceeded the customer’s demand and thus is not required.
Overproduction is the most serious of the seven wastes, and acts as a trigger point for the other six. Having too much of a product in stock results in storage costs, wasted materials, and capital tied up in inventory that is useless.
In addition to reflecting on work that doesn’t bring value to the customer, it is possible to add too much value.
A product may be full of great features, however if the customer does not require those features then they will not be used.
This will lead to an increase in production costs and resources reflected in the final price which the customer will be unwilling to pay.
Where the process of a task is slow or halted, time is wasted. If an employee is waiting on the completion of a previous task before they can complete theirs, then the time they have spent waiting is wasted.
The task must therefore be made more time-efficient by improving the process, increasing manpower or scheduling the workflow in a more effective way.
Any products which do not meet the customer’s expectation must be replaced. Replacing defects costs human resource and a potential loss of customers, and thus, revenue.
The resources used in that particular product have been wasted as the product can’t be used, and the defect may be symptomatic of waste in other areas which has caused the defected product to begin with. Whilst the seven wastes of lean are viewed as negative, identifying where waste occurs can be a great opportunity to improve processes, optimise resources and increase profitability.