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In lean manufacturing, “waste” is defined as anything that doesn’t add value to a product. “Value” in manufacturing is defined as anything that a customer would be willing to pay for.
So, waste is any cost incurred in a process that does not benefit the customer. Lean manufacturing is centered around eliminating waste from manufacturing processes.
Lean practitioners commonly agree on 7 wastes (or muda, as they are referred to in the Toyota Production System):
These wastes were defined by Taiichi Ohno, father of the TPS. Some practitioners include an 8th waste, unutilized talent. While the first 7 wastes are directly related to manufacturing processes, the waste of unutilized talent is specific to manufacturing management.
Transport waste is defined as any material movement that doesn’t directly support immediate production. An improper facility layout, poor production planning, poor scheduling can generate transport waste. Another example is poor workplace organization, which results, in unnecessary additional material transport.
Inventory waste refers to any supply in excess of process requirements necessary to produce goods or services in a Just-in-Time manner. Causes of inventory waste include inaccurate forecasting systems, inefficient processes or suppliers, long changeover times, unbalanced production processes, or poor inventory management and tracking.
Motion waste is defined as any movement of people that doesn’t contribute added value to the product. Examples include moving equipment, reaching or bending, or gathering tools more than necessary, as well as unnecessarily complicated procedures. Motion waste is often caused by ineffective plant layouts, lack of visual controls, poor process documentation, or poor workplace organization.
The waiting waste refers to as any idle time that occurs when codependent events aren’t fully synchronized. Examples of this waste include idle operators waiting for equipment, production bottlenecks, production waiting for operators, and unplanned equipment downtime. Waiting can be caused by inconsistent work methods, lack of proper equipment or materials, long setup times, low man/machine effectiveness, poor equipment maintenance, or skills monopolies.
Overproduction is defined as producing more than is needed, faster than needed, or before it’s needed. This form of waste is most commonly seen in a "push system" supply chain. Automation in the wrong places, lack of communication, local optimization, low uptimes, poor planning, and a just-in-case reward system can cause overproduction waste.
Over-processing refers to any redundant effort in production or communication that does not add value to a product or service. Over-processing waste includes endless product or process refinement, excessive information, process bottlenecks, redundant reviews and approvals, and unclear customer specifications. It is caused by decision-making at inappropriate levels, inefficient policies and procedures, lack of customer input concerning requirements, poor configuration control, and spurious quality standards.
Defect waste is defined as the loss of value do to the scrap, repair, or rework of a product that deviates from specifications. Excessive variation in production processes, high inventory levels, inadequate tools or equipment, incompatible processes, insufficient training, or transport damage due to poor layouts and unnecessary handling can all lead to quality defect waste.
The waste of unutilized talent refers to underutilizing or engaging employees in a process. This could take the form of employees performing unnecessary work when their talent could be utilized in activities that add greater value, or not utilizing employees’ critical thinking abilities and feedback in processes. Unutilized talent also includes allowing employees to work in silos, which prevents them from sharing their knowledge.
Eliminating the 8 wastes from a manufacturing value stream is the core of lean manufacturing. Lean manufacturers should focus on building processes that make these wastes obvious so that they can be addressed—and improvements can be made—immediately.
There are many tools and techniques within lean manufacturing that aim to reduce and eliminate waste. Check out our guides to kaizen and gemba walks to learn more about some of these techniques.
Lean manufacturing, often known as ‘Lean’, is a methodology focused on the minimisation of waste along the value stream of any manufacturing workflow. Lean manufacturing emphasises on optimising quality, time, cost and resources during production. Any processes in the value stream which fail to value-add to the workflow are eradicated.
First introduced in the 1990s, ‘Lean’ continues to impact manufacturers around in world in any industries, be it pharmaceutical, food and beverage or automobiles and more.
The following are the 8 most commonly used lean manufacturing tools which you should know. When deciding which tool to use, remember:
“Some tools require more effort than others and organisations should start with the simplest tool to solve their problems”
Also referred to as ‘autonomation’ Jidoka is a lean manufacturing tool that infuses automation with human intelligence. Manufacturing equipment are programmed to be able to differentiate between the ‘good’ and ‘bad’ throughputs without having the operators to do so manually. This translates to higher productivity gains and lower labour costs because each operator can be freed up to manage multiple machines (also known as multiprocess handling). In a production plant that uses Jidoka, anyone can pause the workflow whenever a problem is observed to harm the quality of the outputs.
Jidoka uses these 4 steps to ensure than an organisation delivers defect-free products:
By eradicating the root cause of defects, Jidoka is useful as a tool to ensure continuous improvements in your production flow.
Speed to market and costs of production often differentiates a ‘good’ manufacturer from a ‘bad’ one.
“Just-in-time (JIT) manufacturing is a methodology used by manufacturers to ‘make only what is needed, when it is needed, and in the amount needed.”
By coordinating raw-material orders from suppliers with production schedules, manufacturers can effectively reduce inventory costs and wastes by receiving inputs only when they are needed for production. Manufacturers also stand to benefit from higher cash flow and lower space requirements.
One note of caution: JIT manufacturers have to be able to forecast their demand accurately.
3. Plan, Do, Check, Act (PDCA) cycle
PDCA cycle is a continuous improvement approach to iteratively improve products, people, and services. Not limited to manufacturers, it involves testing of solutions, analysing of results and improving the processes.
For those familiar with the Scientific Enquiry Method, PDCA is similar to it in terms of:
5S is a philosophy of organising and managing the workspace through the elimination of the 8 wastes defined in the lean manufacturing system. The 8 wastes are:
The 5S stands for:
Simply put, the 5S aims to
5. Six sigma
Six Sigma is a technique used to improve productivity and performing by reducing the likelihood of error. It is a data-driven approach and applies statistical methodology to minimise defects. It is also known to help manufacturers reduce the changeover time from one process to another, reduce the cost of production and increase the satisfaction level of clients.
Six Sigma is characterised by DMAIC – Design, Measure, Analyse, Improve, Control
The production floor works with the management to determine the shared goals and the resources that are required. For example, reducing defective goods of ABC production line by 20%.
Measure is about choosing the suitable metrics and tools to quantify and measure the effectiveness of the plan. It involves:
The stakeholders would analyse the production floor and its various product lines and identify ways to minimise defects. Statistical tools and analysis are often used to determine the source of the problems.
The stakeholders find out the constraints and factors that affect productivity. It often involves hypothesis testing to find out if ‘A’ affects ‘B’ in the process flow
During this step, project teams seek optimal solutions, then develop and test the plan of action for improving a process or goal.
As the final step in six sigma, ‘Control’ refers to the determining if the stated business goals and objectives were achieved and whether the improvements are sustainable.
6. Heijunka (Level Scheduling)
Implementing Heijunka would help manufacturers react to fluctuations in demand and utilise their capacity as well as possible. Heijunka relies on scheduling and production based on customer order and demand, rather than work batches. This brings about the benefits of lower inventory costs (similar to that of JIT) because the organisation manages its inventory level based on order volume.
The 2 ways of scheduling and levelling production are:
1. Levelling by volume
Scheduling your production by the average volume of orders received. This is especially useful for manufacturers with uneven daily demand (e.g. Mon – 3 orders, Tues – 10 orders, Wed – 7 orders etc.). By scheduling the production using the average volume of orders received, manufacturers can have a stable flow of work, 5 days a week to meet the week’s demand.
2. Levelling by type
This is useful for manufacturers who produce a variety of products. It focuses on scheduling production based on the average demand for each product in the overall product portfolio.
7. Overall Equipment Effectiveness (OEE)
OEE = Availability x Performance x Quality
It is a measure of manufacturing productivity for a piece of production equipment, or an entire production line. Measuring OEE provides important insights on production losses and potential areas for improvement.
8. Total Productive Maintenance (TPM)
TPM focuses on reducing the machine downtime of each production line by increasing the reliability of the equipment used during production.
The 3 key components of TPM are:
1. Preventive Maintenance
Preventive Maintenance refers to scheduled maintenance work which is performed on a thorough and periodic basis. The maintenance crew is assigned to check all the equipment for anomalies or problems. This mitigates the chances of sudden breakdowns during normal operations or when the throughputs are suddenly increased.
2. Corrective Maintenance
Corrective maintenance examines the equipment which often breakdown, to analyse the areas needed to be fixed, as well as to determine if there is an imminent need to invest in new physical assets to replace them.
3. Maintenance Prevention
As the name suggests, maintenance prevention involves proper evaluation to ensure that the equipment purchased are suitable, as well as a good fit for the production line. Poorly-purchased equipment may not only expense many resources to maintain, but they may also cause bottlenecks along the production line. This would equate to a loss of investment and productivity for the production facility.
Lean Manufacturing is an important way of management within the production/manufacturing world whose concepts have slowly and steadily entered into the world of business and has proved to be beneficial in all strata of these businesses. Using Lean Manufacturing is all about understanding the concepts behind these tools and techniques. Once you’re familiar with these concepts, implementation can be based on your work culture and production style, as Lean Manufacturing has managed to strike success in all different sectors and forms of businesses.
Selection of the correct lean manufacturing tool to implement in your production facility is not a trivial task. You should take into consideration your organisational culture, production schedules and industry. As mentioned at the beginning, it may be worthwhile to first start with the simplest tool to boost productivity.