Lean manufacturing is all about eliminating waste in the process to increase the overall process efficiency. This process improvement methodology provides tools and techniques to eliminate 8 waste in lean manufacturing. By eliminating waste, this methodology helps organizations reduce costs and provides value to the customer.
In this article, I will be going to discuss the 8 waste in Lean manufacturing in detail like how to identify these 8 types of waste and ways to eliminate them in order to increase process efficiency. Let’s start…
8 waste in Lean manufacturing –
Before getting into the categories of waste we need to first understand the concept of ‘Waste’. In simple language, Waste is any step or action that does not add value to the customer, or we can say waste is any process that the customer does not want to pay for.
The Japanese word for waste is Muda. Muda is considered a non-value-added task within the process. It describes the concept of being useless and unnecessary. The generation of waste not only reduces the efficiency of the process but also makes the workflow unproductive.
That’s why Waste or Muda must be eliminated in the process is a driving concept of Toyota production system and Lean manufacturing. By identifying the process at all levels, improvement teams could easily eliminate waste with the help of different Lean tools.
According to Taiichi Ohno, the chief engineer at Toyota there are 7 types of waste or resources that are commonly misused and mismanaged, and are Overproduction, Defects, Inventory, Motion, Transportation, Overprocessing, Waiting.
Later in 1990 when the Toyota production system started using in the western world, a new form of waste has introduced which is called ‘Unused talent’. This becomes the 8th type of waste that organizations want to eliminate.
Now let’s understand these 8 waste in Lean manufacturing with the help of examples and ways to eliminate this –
1. Overproduction –
Overproduction is producing more than the next step needs or more than the customer buys or we can say producing sooner, faster or in greater quantity than customer demand. It means a product, part, or service was produced too fast, at the wrong time, or in too much quantity for the process.
Waste of overproduction relates to the excessive accumulation of work in process or finished goods inventory. It is the worst form of waste because it contributes to all 8 wastes in Lean. To understand the concept of overproduction, let’s take an example – suppose there is a fast-food restaurant that offers burgers and french fries for lunch.
They do not offer breakfast because they directly open the door of the restaurant at 11 AM for launch. If the cooks light up the grill at 11 AM, then they might start the day behind, as it is possible that several orders will be placed immediately.
However, if the cooks start making burgers at 10.30 AM i.e before half an hour, then they might produce more burgers than required and this may lead to waste or customers don’t like these burgers because every customer wants fresh and hot food in the morning. Making burgers sooner than the customer order time is overproduction.
What if the restaurant manager has done some research to understand how many customers are there in the specific time period like at the start of a restaurant how many customers generally come on each day, similarly in the evening how much is there? With this type of research for each day of the week, he can better manage to fulfill the customer orders.
Let say the manager know the average number of customer comes in first 15 min at the start of restaurant i.e. between 11 to 11.15 AM. As per data, he ordered the cook to begin the burger making at 10.50 AM. and to make 5 burgers per 10 min.
The goal here is to align burger-making with the customer order so that customers don’t need to wait much and still get the fresh burgers. After 1 pm, the manager knows that the order will come quickly so he told the cook to make 15 burgers per 10 min time interval to fulfill customer orders.
After 4 PM, generally, the no of customer visits to the restaurant drops, and the manager knows this as per his research. So during this time, he told the cook to make 10 burgers per 60 min time interval. So that he can avoid unnecessary burger production. If the cook still makes the 15 burgers per 10 min then that will create a problem of overproduction.
So by properly understanding the customer traffic trends in the restaurant, managers are able to estimate needs and create processes that reduce the amount of overproduction waste made in the kitchen while meeting customer demands effectively.
Here are some examples of overproduction –
- Preparing extra reports.
- Multiple copies in data storage.
- Over ordering of materials.
- Preparing equipment or machinery that is not used in the process.
- Producing in larger batches than required to avoid changeover.
- Unstable production scheduling.
- Inaccurate forecasting and demand information.
Ways to eliminate this –
- The key to eliminating overproduction is proper planning. As we have seen in the example, the manager of the restaurant better manages the customer order by properly understanding the customer trends at different time periods. So clear understanding of customer demand in terms of how much, when, and what? we can reduce the overproduction waste.
- Most of the Lean experts and companies recommend implementing the Just in time manufacturing concept to reduce the overproduction waste.
Check out –What is Lean manufacturing? Best way to increase process efficiency
2. Defects –
As per Lean manufacturing, a defect is the failure of a product or process or we can call it a finished product deviating from your customer expectations or in other words, producing products that do not meet customer specifications. Defect leads to rework, repair or scrap and is also called a waste of rework.
Waste of rework includes the waste of handling and fixing mistakes which is common in both manufacturing and transactional settings. Repairing the defects in material or parts adds unnecessary costs because of additional equipment and labor expenses, it also increases the overall process time.
In order to eliminate defects from the end products, organizations institute in-process quality checks that route work with defects back for repair or correction. There are some areas where rework is essential, especially when the material is valuable and work is worth savings rather than scrapping. Then also it is waste in the process which needs to be identified, analyzed, and finally reduced.
Waste of Rework can occur in any type of process. The manufacturing process culls out defective products and parts, in most cases material is reworked for a better outcome and sometimes they are scrapped but in both cases rework is a form of waste.
Call centers and digital work queues are famous for rework because it is easy to send work back and forth in digital format. In some cases, rework does not occur because of the correction of defects but simply because departmental or worker responsibilities overlap.
Overlapping responsibilities refers to a situation in which more than one individual is responsible for the same activity. This usually leads to defect generation. Defects or rework possibilities are also caused by Skill shortage, inadequate training, Incapable processes and suppliers, Operator errors, Transportation, Excessive stock, etc.
Here are some examples of defects –
- Incorrect data entry in the report,
- Paying the wrong vendor.
- Making bad products.
- Misspelled words in communications.
- Material or labor discarded during production.
- The product is mistakenly shipped to the wrong customer.
- The quality inspection process was not followed properly.
Ways to eliminate this –
- Organizations should focus on finding the root cause of the defects/errors like what causing this error? by answering this question organization can easily understand whether the training to the operator is required? or what changes in the process must be done to make it defect-free?
- Answer to these questions helps organizations to take the right decision towards defect prevention. Most of the organizations preferred to implement a defect prevention strategy called Poka-yoke, which helps to reduce defects and hence rework also get reduced.
- Along with this, organizations also focus on creating quality steps to reduce rework and train employees to follow standard operating procedures for quality checks that can help reduce this one of the 8 waste in Lean.
3. Inventory –
Inventory waste is stock and work in process in excess of the requirements necessary to produce goods. It is identical to overproduction except that it refers to the waste of acquiring raw material before the exact moment that it is needed.
This waste not only occurs in manufacturing or service processes but also occurs in work queues, digital data queues, or even email inboxes. For example -if you are receiving 300 emails every day and out of which you are handling only 30 mails per day then the rest of the emails creating inventory waste or we can say the emails that are in the queue.
Inventory is actually a drain on an organization’s overhead because greater the inventory higher the overhead cost becomes (overhead cost is the ongoing cost to operate the business). If the quality issue arises and inventory is not minimized then defective material is hidden in finished goods.
So to remain flexible to customer requirements and to control product variation, organizations must minimize inventory waste. Excessive inventory is caused by a lack of balance in workflow, larger batch sizes, forcing inventory build-up between processes due to overproduction, incapable processes and long changeover time, etc.
Here are some examples of Inventory –
- Over ordering of raw materials.
- Overstocking the raw materials.
- Unnecessary parts and machinery storage.
- Transactions not processed.
- Overproducing work in process.
- Over purchasing of equipment, tools, types of machinery, and materials.
Ways to eliminate this –
- Organizations can reduce the waste of inventory by understanding the process and defining the necessary inventory levels or make inventory decisions based on historic metrics.
- Organizations can also focus on purchasing raw material when it is needed and also create a proper queue system.
4. Motion –
Motion is the unnecessary movement of people and equipment within the process. This includes looking for things like documents or parts as well as movement that is straining. This type of waste is often relevant to people-powered processes in manufacturing, warehousing, shipping, delivery, or industrial fields.
This type of waste is hard to identify and it occurs not only on the manufacturing shop floor but also occurs in computerized offices. For example – In the data entry office, if the data entry employee has to click back and forth between screens when entering information, this could be a waste of motion.
Because if the system is designed so that a number is to be entered in one window and the second number entered in a different window so the click between the windows is wasting motion. Similarly, this type of waste in the office includes unnecessary walking, searching for files, excess mouse clicks, etc.
Sometimes the task that requires an individual to physically move back and forth between the work, extra motion that stems from the poor layout of work. This type of movement not only happens in office work but also occurs on the manufacturing shop floor.
On the shop floor, workers do repetitive movements while working that do not add value to the customers like walking to get materials or tools from other workers, visiting material storage places, visiting newly installed machinery for adjustment, etc.
Waste of motion examines how people move to ensure that value is added. It happens because of Poor workstation layout, poor workplace organization, Larger batch sizes, poor method or process design, etc.
Here are some examples of Motion –
- Extra steps to complete work.
- Excessive walking distance between two operations or processes at the workplace.
- Poorly located materials and daily needed tools.
- Lengthy process steps than needed.
- Lack of standard procedures to follow at the workplace.
Ways to eliminate this –
- Collect and analyze the data to identify the unnecessary movements at the workplace in order to streamline the company processes and by doing this we can eliminate waste of motion. The best tool that is used to track movements at the workplace is a Spaghetti diagram. This diagram helps you find the opportunities for streamlining the movements in the processes.
- Optimize the workplace effectively so that all the necessary things are easily accessible without unnecessary motion. So by tracking movements, we can eliminate one of the 8 waste in Lean.
5. Waiting –
Waiting is the non-productive time in the process, or idle time in the process due to lack of material, people, or equipment. Idle time between the operations or events i.e. an employee waiting for the machine cycle to finish or machine waiting for the operator to load new parts.
Waste of waiting is easily identifiable and it occurs in any type of work environment like manufacturing or in offices. In-office the waiting waste happens like waiting for the software to load, waiting for the meetings to start, waiting for the files that are under review, waiting to get responses on mails, waiting to get approval for project, etc.
Sometimes waste of waiting may lead to defect generation because instead of waiting people love to take shortcuts and that may cause an error in the work. To avoid this type of shortcut taking mentality it is better to work on reducing waiting waste which is one of the most easily identifiable wastes amongst the 8 waste in Lean.
In the manufacturing environment, waste of waiting is a big problem it includes waiting for a reply from suppliers about materials, waiting for the proper instructions to start daily work, waiting for the machinery to start, waiting for low capacity machinery to process material, etc.
Waste of waiting occurs when steps in the process are not properly coordinated, when processes are unreliable when work is batched too large, during rework, and during the long changeover between staff or machines.
Here are some examples of Waiting –
- Production cycle stopped when a problem occurs in the process then everybody waits till the problem gets resolved.
- Pausing steps in the process while the previous machines finish the work.
- Human or technical delay in the process.
- In the restaurant customers waiting to get their orders.
- Delayed work due to lack of communication from another group.
- Showing up on time for a meeting that starts late.
Ways to eliminate this –
- Waste of waiting can be eliminated from the processes by balancing the machinery, people, and production. Those who work close to the process should focus on balancing these 3 factors to improve overall processes.
- Design processes to ensure continuous flow by using standardized work instructions. Along with this advanced planning of work and scheduling tactics could help to reduce the waiting waste.
6. Overprocessing –
Overprocessing is tasks, activities, and materials that don’t add value, or we can say waste of overprocessing relates to overprocessing anything that may not be adding value in the eyes of the customer.
This occurs when an employee or process inputs more resources into products or services than is valued by the customer. It happens because of ignorance while working, a desire for perfection, or even excitement about work, etc. Sometimes overprocessing occurs because an employee has not had training on the most efficient way to handle a task.
In other cases, it happens because an employee or process is more thorough than is worthwhile. A goal of any process should be to do just enough useful and necessary work to ensure that customer or end-user expectations are met. Otherwise, this waste of overprocessing can waste time, money, efforts, and talent.
This is one of the most common waste types amongst the 8 waste in Lean because it also occurs in all types of work environments whether it is manufacturing, services, or office work. In-office type environment overprocessing includes double data entry in the reports, unnecessary steps to follow while making contracts with suppliers,
Extra processing of reports than needed, required unnecessary signoffs on the approval documents, unnecessary process steps in daily office work, etc. On the other hand, in the manufacturing environment, this waste includes unnecessarily adding more features to the product than needed, unnecessary usage of high capacity machinery than needed,
Performing more analysis than required or it is called analysis of paralysis, Working more on the final finishing of a product than needed, etc. Waste of overprocessing is generally caused by a poor product or tool design, also not properly understanding customer’s wants, unclear quality acceptance standards, no standardization of best techniques in the processes. etc.
Here are some examples of Overprocessing –
- Reports that contain more information than the customer wants.
- Doing unnecessary quality inspections or quality checks.
- Installing unnecessary parts or features to the product.
- Unnecessary welding of joints in automobile frame.
- Slow approval processes in the office.
- Cleaning and polishing beyond the required level.
- Painting on unseen areas.
Ways to eliminate this –
- Understand the customer expectations and translate them into correct specifications. This must be followed by the design and production team. Also, use modern tools and technologies to reduce the processing time which makes the organization more efficient and waste-free.
- Use effective tools like Value stream mapping which helps the organization to identify non-value-added activities in the process. When non-value-added activities are eliminated from the process it automatically reduces the waste of overprocessing.
7. Transportation –
Unnecessary movement of materials and goods from one location to another is the waste of transportation or conveyance. Unnecessary movement of material can lead to product damage and defects. Also, unnecessary movement of people and equipment can lead to a generation of other types of waste like motion and waiting which results in high overhead costs.
For example – In the office, If an expense report is printed and then carried to a manager for approval who then routes it in an inner office envelope to a director, who then carries it to the accounting department then and follow further steps So here unnecessary movement of that report is happening hence called as a waste of transportation.
On the manufacturing shop floor, if the material is not available to nearby storage then every time unnecessary transportation of material needs to be done from outside to the storage area this is also called transportation waste because this transportation of material is not adding value to the output.
In both cases, organizations should use modern tools and technology to reduce this waste of transportation. This is one of the worst forms of waste amongst the 8 waste in lean because excessive transportation can cause other types of waste like motion, waiting and defects. So reducing this form of waste help reduce 3 other types of waste.
Excess transportation can be caused by poor layouts like the large distances between two operations, Lengthy or complex material handling systems, Large batch sizes, Working at a faster rate than customer demanad, Multiple storage locations, etc.
Here are some examples of Transportation –
- Frequent transport of raw material or parts within factory because layout not optimized.
- Bad coordination amongst the logistics team.
- Movement of equipment between two operations which are far away from each other.
- The material suppliers who are far away from the factory location need more transportation time for material transport.
- Extra steps in any process which are not adding value to the final output.
Ways to eliminate this –
- Tools like spaghetti diagrams, process maps, or value stream maps can help you identify the areas where the waste of transportation might exist.
- Once you identify this waste you can eliminate it by making changes in the process, layouts, or inventory requirements for the work.
- If waste of transportation is not due to poor process design or work are layout then it might be related to another form of waste.
8. Unutilized talent –
Toyota originally defined the seven common forms of waste but later Taiichi Ohno agreed that other types of waste also exist. Then the new form of waste comes into the picture i.e. Unutilized talent. This added to the list of 8 waste in Lean manufacturing.
This type of waste occurs when there is separation in management and employee roles. Management has all the authority to make decisions but when they have not considered the suggestions or improvement feedback from the working staff then that becomes a waste of ideas and their talent.
Because management thinks that they are fully decision-makers in the organization and employee role is to simply follow orders and execute the work as planned. But by not engaging the frontline worker’s talent and expertise, it is difficult to improve the processes.
Talent can be wasted when a process doesn’t make the most use of the labor or staff available. Hiring the wrong person, putting staff in the wrong position, or ignoring a staff member’s growth potential could all be instances of waste of unused talent.
Wasted talent is more a concern for leadership and human resources than for process improvement specialists, though Six Sigma experts should be aware that the way personnel resources are handled can drastically impact the efficiency of a process.
Here are some examples of Unutilized talent –
- Placing employees in a position below their skills and qualifications.
- Employees or machine operators are poorly trained.
- Employees are not encouraged to come with new ideas to solve workplace problems.
- Lack of communication between top management and company staff.
- Failure to involve people in workplace design and development.
Ways to eliminate this –
- By engaging employees and incorporating their ideas, providing proper training and growth opportunities, and involving them in the creation of process improvements, also encouraging people to take ownership of their areas, processes and making them problem solver helps the organization to improve overall process performance and by doing this they are utilizing the talents of people.
- Arrange skill development programs and training for employees, encourage them to provide suggestions while doing problem-solving or improvement work not just fully rely on expert’s opinions, respect your employees, nurture them and involve them in decision-making processes.
Elimination of these 8 waste in Lean manufacturing happens in some steps like the first organization should focus on identifying these wastes using value stream mapping. Value stream mapping is an effective tool to highlight non-value-added activities in the process. After that classify waste into the 8 categories that we discussed in this article.
Then organizations should focus on creating plans to reduce and eliminate each type of waste using different tools and techniques. Continuously involve the team and people who work close to the process in the process improvement activities and waste elimination.
Over the period of time, it becomes a daily routine of organizations staff to reduce these 8 waste in Lean at the workplace. Then they build up the confidence to improve the process and will become problem solvers. This will take time and also need constant support from management.
Here I have just tried to give you basic steps on how waste elimination happens. In the upcoming articles on this topic, we will understand the detailed steps on how to eliminate waste at the workplace.
Identifying 8 waste in Lean manufacturing and work towards its elimination is one of the most important areas organizations should focus on to improve overall process efficiency and performance. In this article, we discussed in detail these 8 types of waste as per Lean thinking with real-life examples and ways to eliminate each type.
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