What is Lean Manufacturing?
Lean manufacturing is an umbrella term that sits over a range of tools and techniques manufacturers use to improve the productivity of their plants.
The term was first coined in 1988 and is an evolution of the Toyota Production System which revolves around the concepts of maximising value-added (VA) activities and minimising non-value-added (NVA) ones.
In a manufacturing environment, all the work done to a part is classed as value-added. Conversely, all the time a part spends in a production cycle without having work done (e.g. waiting for the next operation) is known as non-value-added time and is seen as a waste.
The essence of lean is to reduce that waste through a continual cycle of analysing and improving the activities within the whole organisation.
What are the core principles of Lean Manufacturing?
There are five core principles of lean, which are:
1. Customer Value
Each operation in a production process adds value to a component. Therefore, the first principle of lean is to view the added value through the customer’s eyes, i.e. which are the activities they would be happy to pay for if they watched the process. Switching to this viewpoint allows the manufacturer to understand the customer’s concept of value, then meet that value by producing the goods most efficiently.
2. Understanding the Value Stream
All the processes in a manufacturing organisation are linked together and are known as the Value Stream. A manufacturer’s value stream can be mapped from the initial enquiry to the final invoice to understand the VA and NVA activities and where waste exists in the process.
3. Improving Flow
By removing waste and other barriers to production, a manufacturer can improve the flow of products through the facility. Stop-start production creates waste which creates cost and increases the overall processing time unnecessarily.
4. Creating a Pull System
A push system relies on demand forecasting and inventory management to meet anticipated customer demand in the future. However, a push system is only as good as those forecasting techniques. Push systems focus on maximising productivity at each stage of production. However, this leads to bottlenecks forming at operations with long processing times. These bottlenecks create waste in the form of WIP.
A pull system only produces when there is demand from the next operation. By pulling work through the production system, a manufacturer will reduce inventory costs and waiting times. As a result, they will be able to offer lower prices and quicker turnaround times.
5. Continuous Improvement
Lean manufacturing isn’t a single-hit activity. Lean practitioners never accept the current situation as perfect. Instead, they continually strive to achieve perfection, knowing it’s an ideal that can never be attained. The identification and elimination of waste is a never-ending process of improvement.
What are the most common Lean Manufacturing tools?
Although there are many Lean tools, two of the most common ones are:
5S is a workplace activity that results in an organised, uncluttered shop floor that reduces waste and establishes a continual improvement mindset. Originally these were five Japanese words Seiri (organise), Seiton (orderliness), Seiso (cleanliness), Seiketsu (standardise), Shitsuke(discipline).
However, to make 5S work in the West, those words became:
Removing everything from the shop floor that isn’t needed. Not only scrap but old jigs and fixtures, tooling and general clutter.
Arranging workstations and shop floor processes in the most logical way to reduce unnecessary movement of people and parts.
Often, people take this to mean cleaning up. However, it also includes carrying out machine maintenance and making sure tools are put back in their correct location. Everyone takes responsibility for their work area and the whole factory, rather than leaving it to cleaning staff.
After carrying out this kind of shop-floor activity, it’s easy for things to slip. However, by establishing a standard work area with photos or instructions of how the station should be arranged, the 5S activities become habitual, rather than a one-off clean up.
The most crucial and often overlooked part of a 5S process is to make it a long-term activity that changes an organisation’s culture. Then, when the end of the 5S project is reached, it returns to the start to continually improve the business.
The Seven Wastes
When manufacturers talk about waste, they don’t (only) mean the bi-products or scrap from their production process. In a Lean context, waste is defined in seven ways:
Moving raw materials in and finished goods out of the company and moving parts around the factory during the production process.
Raw material stock, work in progress and finished good stock are all classed as wastes because they represent cash tied up in the business. Minimising inventory frees up cash and physical space.
As transport refers to the movement of goods, motion refers to people moving around the facility and unnecessary movements when operating a machine. For example, when someone bends down to pick up a part rather than the piece being at waist height.
Operators waiting for tools or machines or parts waiting for their next operation are all creating waste.
Producing more parts than the customer requires is a waste of processing time and material resources. Running a large batch to gain an advantage from a long set-up time may look economical on paper, but it ties up cash and physical space.
Doing more than the customer requires is seen as a waste. If the customer hasn’t asked for it, they won’t pay for it.
Defective parts waste all the resources that went into their production—raw materials, processing time, and consumables.
Six reasons why Lean Manufacturing can give you a competitive advantage
When a manufacturer designs their processes in line with their customers’ requirements, eliminates all forms of waste, and focuses the workforce on continuous improvement, their quality levels rise massively.
Running a lean manufacturing system makes a manufacturer more responsive. By operating with minimum stock levels, smaller batches, and using a pull system, they can adapt to sudden changes without much disruption or cost. New products can be developed and introduced quickly, which is perfect for a jobbing shop.
Improved Customer Service
By moving the focus to the customer’s perception of value, a lean manufacturing company can’t help but give fantastic customer service. In addition, reducing lead times and costs by eliminating waste helps manufacturers offer quick turnarounds and competitive pricing.
Implementing a lean manufacturing system isn’t possible without all the company’s employees buying into the concept. By taking part in the lean activities, staff become more engaged with the company, seeing their inputs having a direct effect. In addition, an engaged workforce makes recruiting new staff so much easier as employees become advocates of the company.
Positive Environmental Impact
Sustainability is an essential factor for many companies when assessing new suppliers. Adopting a lean manufacturing approach reduces waste, which is better for the environment as valuable resources are used effectively.
Lean manufacturing is a win-win scenario for manufacturers and customers. Using the various lean tools and techniques to eliminate waste and improve productivity allows companies to offer competitively priced, high-quality products which benefit everyone.