What is Lean?
Lean is a systematic method or approach for eliminating waste. Waste is anything that does not add value to your product or service. You may want to ask, ‘what is value?’ Simply put, ‘value’ is anything a customer is willing to pay for. In other words, anything that exceeds just the right amount of equipment, materials, parts, space etc. is considered a waste.
Elimination of waste improves quality, reduces production time and cost. Although eliminating waste seems like a simple thing to do, it is actually not that easy. One of the tenets of ‘Lean Thinking’ is to identify activities or steps that constitute ‘waste’. For this reason, Taiichi Ohno of Toyota introduced a concept known as ‘Muda’. Muda is the Japanese word for wastes. He originally identified seven types of waste or muda. Later, an eight waste was added (a good mnemonic to use here is (DOWNTIME). Below shows the waste and their description:
Defects: This refers to the efforts put in a rework by checking and fixing errors or mistakes. Also, it means having to discard or rework a product as a result of defective components. All these results in delays and additional cost.
Over-production: This waste arises when more than the required product is produced.
Waiting: This refers to the time spent when a product is idle. In other words, it is the time spent when a product is not being worked on or transported.
Non-utilised talents: This waste arises when employees do not use their skills optimally due to restrictions. Essentaially, it means not leveraging people’s talents and skills.
Transportation: This occurs when products, equipment, material, etc. are moved from one place to another without any value addition. Hence, transportation exposes inputs to damage, loss, theft, delay, etc.
Inventory: This waste arises due to the unnecessary storage of material or product. In other words, the longer a product stays, the more the waste. A smooth, continuous flow of work reduces the amount of excess inventory.
Motion: This refers to the damage to equipment, wear and tear, unnecessary movement by workers, injuries or fatigues.
Extra-processing: This occurs when more than the required processes and steps are carried out. These extra processes do not add value to the product or service. Also, it involves the use of complex, expensive or high-value materials beyond what the customer requires.
Having looked at the meaning of ‘Lean’ and ‘waste’, let’s now discuss the principles that will help eliminate waste.
The five principles of Lean are:
Value: Firstly, define what is of value to the customer. You have to decide what the customer is willing to pay for. In other words, find out what the customer needs.
Value Stream: Secondly, identify all steps and processes that are needed to take the product from start to finish. Here, the goal is to identify every step or activity that does not add value and then eliminate them.
Flow: After removing waste from the value stream, the next thing to do is to ensure a constant flow of value-creating steps. In other words, there shouldn’t be any interruptions or delays.
Pull: As a result of constant flow, the time it takes for products to reach the market can improve significantly. Therefore, it becomes easy to deliver products ‘Just in Time’ (JIT). With this approach, customers can ‘pull’ products from you anytime.
Perfection: Finally, you have to continuously improve the process. You must put in considerable time and effort in improving your existing processes to meet customers ever-changing needs.
Lean Tools and Techniques
Professionals need tools and techniques to carry out their day-to-day activities. Similarly, Lean professionals need tools to help them eliminate waste. Now, let’s look at some of the tools and techniques they use.
Kanban: This is a visual representation that helps manage inventory or set of activities. In other words, Kanban boards show at a glance the level of backlogs.
Just in Time: This is a ‘pull’ approach whereby customers demand are met on time.
Jidoka (Autonomation): This automation stops the production line if a defect or error occurs.
Kaizen: It’s an approach whereby small teams meet on a regular basis to discuss process improvement issues.
Heijunka: The aim here is to evenly distribute workload thereby balancing production lines.
Gemba (Go & See): As the name suggests, it means to go to the actual place of work. The purpose of Gemba is to observe a process, how it is executed and then make recommendations for improvement.
SMED (Single Minute Exchange of Dies): This provides an efficient and rapid way of reducing the time it takes to complete equipment changeovers.
VSM (Value stream mapping): As discussed earlier, VSM helps identifies process wastes with the goal of eliminating them.
Poka-Yoke: This is a mechanism in a process that helps an equipment operator to avoid mistakes.