What is Lean Manufacturing? : An Introduction

In an enterprise, resources are not utilized with their 100% efficiency. This loss in efficiency is known as waste. Ultimate goal of an organization is to reduce this waste to zero. Lean manufacturing is a technique to reduce waste in an industry or organization. In this article we will focus on what is lean manufacturing? Why do we need Lean? and tools used to implement lean manufacturing in any enterprise.

Lean manufacturing is a technique derived from Toyota 1930 “Toyota Production System or TPS”. It’s key goal is to eliminate waste and improve efficiency by utilizing five principles of lean manufacturing to deliver more value to your customer.

Waste (activities that add no value to the customer) in an industry can be reduced by taking full advantage of available resources (human, machines, material or product). This helps in increasing efficiency and gives more value to your customer.

Please note the concept of lean manufacturing is not limited to manufacturing companies only. This can be applied to any industry such as design center, outsourcing or construction.

Types of Waste in Lean Manufacturing

The ultimate goal of lean thinking is to eliminate the waste. Therefore to understand Lean Thinking, First we need to understand what is considered waste in an industry. According to Toyota Production System or TPS Waste can be of the following three types.

  1. Muda (Non-Value added Processes or Process waste)
  2. Mura (inconsistency)
  3. Muri (overburden)
Muda : Non-Value added Processes or Process waste

Muda stands for Non-value added tasks or Process waste. Non-value added tasks are the tasks that add no value to your customer. Muda can be classified into two types.

Muda Type 1 : This involves the tasks that do not add any value to the customer but they can not be skipped. For example, most of the time packing of a product is a waste for a customer, But it is required for safe transportation of the products.

Muda Type 2 involves the non-value added tasks that can be eliminated to save customer money. For example Defects in a product, Excessive movement of product, inventory, non-utilization of resources are the examples of Muda in an industry.

Mura : Inconsistency

Mura Stands for inconsistency or non-uniformity in the distribution of work. For example, Consider two engineers working in a company at the same level. if “Engineer A” is doing overtime to deliver given tasks. Whereas “Engineer B” finishes his work in half a day. There are some problems with the distribution of work that need to be corrected. Therefore it is always recommended to do proper distribution of work between employees and machines.

Muri : Overburden

Muri Stands for Overburden. In a system if only a few people or machines are assigned lots of responsibility or Overwork. They can not give their 100%. This is a waste due to uneven allocation of resources. For example, if in a factory utilizing machines or workforce with more than 100% capacity can cause machine breakdown or workforce dissatisfaction.

Basic Lean Principles to create a Lean System

Implementing Lean principles in a system company or industry develops an approach towards continuous improvement. Following five principles are used to create a lean system in an industry.

  1. Identify the value you want to deliver to your customer.
  2. Mapping the Value Stream.
  3. Continuous Workflow.
  4. Pull System.
  5. Continuous Improvement.

Let’s discuss these five lean principles in detail.

This image shows five principles used to create a lean system.
1. Identify Value for your Customers

An industry can grow only when it continuously increases their product’s value for their customers. Value for a customer is what they are willing to pay for a product or service.

Value of a Product can be increased by:

  • Reducing product cost.
  • Improve product quality.
  • increase user satisfaction.
  • Providing better products from the previous one.
  • Providing more or better services of function in a product.

For example, For a music streaming app. A  company can increase their streaming app product value for premium customers by removing ads. Or if you are a brake pad manufacturer For OEM. You can increase your product value by improving product quality, timely delivery or reducing manufacturing cost.

Therefore the first step in lean manufacturing is to identify areas where you can provide more value to your customers.

2. Mapping the Value Stream

Once you identify the area where you want to increase the value for your customer. Next step is mapping the value stream. Mapping involves writing down all activities to manufacture the part and deliver it to the customer. In the context of manufacturing a machining part involves activities shown in the image below.

This image shows Value Stream to Manufacture Machined Block
Value Stream to Manufacture Machined Block

As shown in the above image, manufacturing a metal block involves activities from purchase of raw material to product dispatch to the customer. Value stream is mapped to identify non-value added activities or waste and eliminate them from the manufacturing process.

For the above examples, non-value added activities to manufacture machine block can reduced by:

  • Utilizing the same raw material to manufacture different parts. This will reduce stock requirements in the inventory.
  • Using a Jig or fixture to set up the part on the milling and drilling machine.
  • Reducing number of inspection stages.
3. Continuous Workflow

After waste or non-valuable operations are identified and removed. Next step is to ensure that these changes do not have any impact on the product quality. Afterwards these changes are conveyed to all stakeholders and implemented on the shop floor.

4. Pull System

Inventory is also a waste or non-productive in a production system. Therefore the pull system is used to minimize or completely remove the inventory.

In the Pull system, a customer has to pull the product from the manufacturer when required (With some Lead time). In this way a manufacturer is not required to build products in advance. New parts are manufactured as per actual orders not as per forecasting.

In this way raw material inventory and finished product stock is minimized. For example, car manufacturers take advance booking for premium high value cars. In this way they have a fair idea about demand for a particular model and production planning is done accordingly.

5. Continuous Improvement to achieve Perfection

There is always a better way of doing things. One of the five basic principles for lean manufacturing is to reach for perfection. To achieve perfection continuous improvement should be in company culture.

Kaizen (change for the better) is a Japanese philosophy used for continuously improving manufacturing operations that involve all employees. teamwork, personal discipline, improved morale, quality circles, and suggestions for improvement.

Essential Lean Manufacturing Tools

Here is the list of essential tools to implement lean thinking in an industry. It is not mandatory to use all Lean tools in all scenarios. Best practice is to select the right tool according to requirements.

This image shows the list of tools used to implement lean
Kanban

Kanban is a workflow management technique that helps in scheduling various activities. It helps in visualizing workflow, maximize efficiency and improve continuously. To achieve these goals following Kanban practices are used:

  1. Visualize the Workflow
  2. Limit work in progress
  3. Manage Flow
  4. Make process
  5. Get Feedback
  6. Improve Collaboratively
Pull System

As discussed above, in the Pull system, a customer has to pull the product from the manufacturer when required (With some Lead time). In this way a manufacturer is not required to build products in advance. New parts are manufactured as per actual orders not as per forecasting.

Kaizen : Continuous Improvements

Kaizen is a Japanese term that means “continuous improvement” that involves all employees. It can involve any change in product manufacturing process to improve quality, reduce cost, increase product value or eliminate waste. Teamwork, discipline, improved morale, quality circles, and suggestions for improvement are key Kaizen elements.

5S : Scientific way to manage the Workplace.

5S is a scientific way to manage a workplace. Here 5S stands for following five steps in managing things in order and cleaning on a regular basis.

  • Sort
  • Set in Order
  • Shine
  • Standardize
  • Sustain

Poka-yoke technique is a type of mistake proofing technique that involves finding the root cause of error and ensuring error or mistakes does not occur during manufacturing or operation of the product.

It is a very good tool to prevent manufacturing and user related errors and improve customer satisfaction. Following two techniques are used in Poka-Yoke to avoid mistakes during product operation and manufacturing. Click this link for more details on poka-yoke techniques in Lean Manufacturing.

  1. Make sure error does not occur in the first place.
  2. If error occurs, error becomes obvious. In other words, Mistakes should be detectable.
Root cause Analysis

Root cause analysis is a systematic problem solving technique that involves the finding the root cause of the problem to solve it. This process involves some of the following steps.

  1. Define the problem.
  2. Collect data.
  3. Identify issues that contributed to the problem.
  4. Find the root cause.
  5. Identify and Implement the solution.
3M : Waste Elimination

This is same Toyota Muda, Mura and Muri model discussed above for the waste elimination.

Just in Time (JIS)

Just in Time also known as JIT or Toyota Production System (TPS) is an inventory management technique primarily used to reduce time within the production system. It helps in increasing efficiency, reducing waste and manufacturing cost.

Heijunka : Reduces manufacturing Lead time and Inventory.

Heijunka is a lean method of fulfilling customer demands without pressurizing the manufacturing unit. It helps in optimizing and utilizing manufacturing capacity in the best possible  way to meet demand. Heijunka helps in processing orders according to customer demands rather than manufacturing them in batches.

Andon : Visual feedback system (indicates production status, alerts etc.)

Andon in Lean Manufacturing is a visual feedback system that is used to alert production about any problem or production status in real time. So that an appropriate action can be taken.

KPI (Key Performance Indicators)

Manufacturing Key Performance Indicators (KPI) are used to measure and track the performance towards organization goals. KPI’s provide required data to identify improvement areas and reduce waste.

Total Productive Maintenance (TPM)

Proactive and preventative maintenance helps in reducing machine downtime. Latest technologies such as IoT in manufacturing and Machine Learning in manufacturing are playing key role in total productive maintenance,

Benefits of Lean Manufacturing

Following are the benefits of implementing lean principles in manufacturing.

  • Better utilization of resources.
  • Reduced Inventory
  • Increased Productivity.
  • Improved Quality
  • Reduced manufacturing cost.
  • More value to customers.
  • On time delivery.

We will keep adding more details in lean manufacturing. Please add your suggestions, comments or questions on Lean Manufacturing in the comment box.

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