Lean

The Lean philosophy is based on elimination of waste in all forms at the workplace. Some of the specific lean methods are just-in-time inventory management, Kanban scheduling systems and 5S workplace organization. These concepts were developed by a Japanese company, Toyota, an automobile manufacturer in the 1940s which popularized the concepts and made it widespread for removing waste thus, graduating as best practices in many industries beyond automotive companies. So the lean principles applied to production has the potential for both improved profitability and increased complexity.

Lean Origins

The origin of Lean Manufacturing evolved over times. In 1890’s Frederick W. Taylor began to analyse individual workers and their work methods. Thereafter Frank Gilbreth added Motion Study and invented Process Charting. Then Lillian Gilbreth introduced psychology by studying the motivations of workers and how attitudes affected the outcome of a process. All these ideas led to the invention of techniques for waste elimination, which is a key component of JIT and Lean Manufacturing.

Then in 1910, Henry Ford developed and implemented the first comprehensive Manufacturing Strategy by arranging all the elements of a manufacturing system like people, machines, tooling and products, in a continuous system or an assembly line for manufacturing the Model T automobile.

Toyota Production System

During the period of 1949 to 1975, Taichii Ohno and Shigeo Shingo, in Toyota Motor Company,, began to incorporate Ford production and other techniques into an approach called Toyota Production System or Just In Time. But, later they found fallacies in the Ford system, specifically with treatment towards employees as Ford used employees only for muscle power.

Toyota Production System (TPS) primarily focuses on two concepts muri and muda. Muri focuses on the preparation and planning of the process, that is what work can be eliminated in the design process. Muda are those waste steps and processes that add cost. Muri is used in new product design and muda is used to improve existing operations.

Lean Concept and Tools

We cannot say that the concept of lean is used for few techniques or processes but it is a journey in itself. Lean concepts takes a holistic view of the organization and incorporates various phases which make use of varied techniques and processes.

Steps involved in the process of lean manufacturing

1. Define value from the customer’s perspective
2. Map the value stream
3. Create flow by removing causes of waste
4. Create pull if flow is difficult to achieve
5. Measure and validate
6. Practice continuous improvements

Lean Process

Four key Lean concepts of Lean Process – identifying value, the value stream, pull, and perfection.

1. Identifying value – The process of identifying value must always start with the customer, who gets the product or service, or the downstream process customers. In case an activity does not add value for a customer, then it indicates that the process needs to be improved. It is very important to identify value as it gives direction to the organization. Some of the activities that add no value in the system are, wasted movement, re-work, or extra inspection time. Then think about what it is that creates value in a process or product. The best way is to view it from customer’s point of what they perceive as value and then asses which of the outlined activities brings the most value for the organization.
2. Value stream – The next important lean concept is known as value stream, which can be defined as a series of activities and processes that aims to create value in an organization. In order to determine the value stream, the technique of value stream mapping is used. Value stream mapping involves capturing lots of data – Primarily cost and quality data. This process of data gathering includes suppliers and customers as well. When all the information is processed, it is then important to decide whether any activities or processes requires restructuring so as to improve overall performance. One of the methods used in this case involves creation of current state maps with data, and then think about future state maps and then analyse the differences between the two site maps.
3. Pull system – As the name suggest this key concept of lean allows the customer to trigger a pull through of inventory or information instead of pushing inventory through planning into the system, in order to support downstream processes based on consumption. This key concept helps to greatly reduce and eliminate wait time associated with traditional planning processes. Also this would lead to minimal inventory being required a any given time.
4. Perfection – The concept of Lean is based on the dedication for continuous improvement. In lean the only acceptable goal towards safety would be zero that is zero injuries, deaths, lost time, accidents, or even near misses. So there needs to be the same attitude toward waste and defects in the processes that is zero is the only acceptable goal towards waste. Since the zero goal cannot be achieved yet there is always continuous improvement that to drive perfection.

Value in Lean

In order to determine the value in Lean we first need to what actually Value means?

Value is basically how well a product or service actually meets the customer’s requirements. Therefore it becomes essential to work out in the early stages if a customer is willing to pay for the product or service being offered – if the answer to that is clearly a yes, then you can say that this has value. So we can say that value-added activities would be those activities that actually add value to the end product and bring what the customer is willing to pay for in that product or service. Value addition can be measured  by breaking down each activity in the process, using value stream mapping.

Mudas and 3Ms

Muda is a Japanese terminology meaning waste  according to the Japanese management philosophy. Primarily there are 7 mudas or seven types of waste found in a manufacturing process,

1. Overproduction – Overproduction is witnessed when production is more than the customer requirement leading to other types of wastes such as inventory costs, manpower and conveyance to deal with excess product.
2. Extra Inventory – Holding extra inventory at any point does not add any value as it blocks the financial resources of the company and is further exposed to the risk of damage, obsolescence, spoilage, and quality issues. The extra inventory produced all requires space and manpower for proper tracking and
3. Defects – There is another type of waste which occur due to broken equipment results in defective products leading to unsatisfied customer
4. Non-value Processing – Non-value processing is also referred as over-processing, which causes wastage of more resources in the process of production, including wasted movement and time. So any processing that does not add value to the product is waste example – in-process protective packaging adds to the extra manufacturing steps.
5. Excess Motion – Another form of waste caused due to excess or unnecessary motion due to poor workflow, poor layout, housekeeping, inconsistent work methods or lack of standardized procedures.
6. Transport and Handling – Transportation and handling waste occurs due to some shipping damage and includes pallets not being properly stretch wrapped (wasted material), or if a truck is not fully loaded to use floor space efficiently.
7. Waiting Time – Any wastages in time, caused due to broken machinery, lack of trained staff, shortages of materials, inefficient planning and waiting for material is a part of waste.

3Ms

According to Japanese philosophy when they talk about waste it clearly points towards the three Ms – Mura, Muri and Muda. These wastes (Muri and Mura) are often far more important to tackle than Muda and often are the underlying causes of the Muda that you observe within your processes.

Lets now get clarity on the 3 M’s

1. Muda: Non-value adding actions within the processes
2. Muri: Actions that either overburden or are unreasonable
3. Mura: Refers to waste of unevenness or inconsistency

Mainly there are 8 distinctive types of muda which leads to waiting times, and therefore longer lead times in a process. So only dealing with muda does not work, there is a reason why the muda is there which is connected with the other two wastes: muri and mura.

Which indicates that the three enemies of Lean are interrelated and must be considered simultaneously. These three enemies of lean can be found in both production and official processes. Since Mura is the waste of unevenness therefore it creates many of the seven wastes that are observed under Muda. So we can say that  Mura drives Muda. Therefore by failing too smooth to the demands we put unfair demands on our processes and people and add to the  creation of inventory and further increases waste.

Now Muri related to causing overburden, which means giving unnecessary stress to the employees and the processes. This overburden is caused due to Mura and other set failures in the system such as lack of training, unclear or no proper defined ways of working, the wrong tools, and ill thought out measures of performance.

We can here say that, Mura causes Muda, i.e., the 7 wastes are symptoms of our incompetence to handle Mura and Muri within our processes.

Waste Elimination Techniques

Some of the waste elimination techniques used in lean manufacturing are,

1. Pull System – It is the technique for producing parts as per the customer’s demand. Companies need to have a Push System or building products to stock as per sales forecast, without firm customer orders.
2. Kanban – It is a method for maintaining an orderly flow of material. Kanban cards are used to indicate material order points, how much material is needed, from where the material is ordered, and to where it should be delivered.
3. Total Quality Management – It is a management system for continuous improvement in all areas of a company’s operation. It is applicable to every operation of the organization and involves employees.
4. Quick Changeover (or SMED – Single Minute Exchange of Dies) – It is the technique for reducing changeover time to change a process from running a specific product manufacture to another. It enables flexibility in final product offerings and also to address smaller batch sizes.
5. 5S or Workplace Organization – It is a systematic method for organizing and standardizing the workplace and is applicable to every function in an organization.
6. Total Productive Maintenance – It focuses on proactive and progressive maintenance of equipments by utilizing the knowledge of operators, equipment vendors, engineering and support persons to optimize machine performance thus, drastically reducing breakdowns, unscheduled and scheduled downtime which results in improved utilization, higher throughput, and better product quality.
7. Takt time – It is a measure of customer demand expressed in units of time and is calculated as Takt time = Available time per shift / Demand per shift or Cycle time/Number of People
8. Visual Controls – They provide an immediate understanding (usually thirty seconds) of a condition or situation like what’s happening with regards to production schedule, backlog, workflow, inventory levels, resource utilization, and quality. It includes kanban cards, lights, color-coded tools, lines delineating work areas and product flow, etc.
9. Poka Yoke or Mistake Proofing – Poka Yoke is a quality management concept developed by a Matsushita manufacturing engineer named Shigeo Shingo to prevent human errors from occurring in the production line as, extensive automation and computerization is expensive. Poka yoke is implemented by using simple objects like fixtures, jigs, gadgets, warning devices, paper systems, and the like to prevent people from committing mistakes.

Value Stream Mapping (VSM )

Value stream is defined as the set of activities derived from customer’s request for their satisfaction and VSM records these activities as icons or symbols. Further Value stream mapping is a lean-management methodology used for analyzing the current state and designing a future state for the series of events that takes a product or service from its beginning through to the customer.

Primarily, VSM is a visualization tool focused on understanding and streamlining work processes using icons and symbols to depict various elements and improve the flow of material and information. The process of Value Stream mapping helps to identify and decrease waste or non-value addition activities, in the process. VSM can also be used as a strategic planning tool and as well as a change management tool.