Lean vs Six Sigma: What Makes Them Different and How to Choose the Right One

Understand the differences of Lean vs Six Sigma before you decide which to choose

If you want to improve your products and manufacturing, there are two major methods you’re likely to use:

Lean vs Six Sigma.

Lean manufacturing is well-known for eliminating waste while Six Sigma is well-known for decreasing product defects.

In some ways, these methods are closely related. In other ways, they’re very different.

We’ll help you decide which of these methods you should put into practice in your factory by comparing their differences.

First, let’s define Lean manufacturing and Six Sigma.

What is Lean?

The Lean manufacturing system, often referred to as Lean manufacturing, Lean production, or simply “Lean” is a system for maximizing product value for the customer while minimizing waste without sacrificing productivity.

Lean manufacturing as we know it today has its roots in the Toyota Production System (TPS), which was created by Taiichi Ohno and Eiji Toyoda in Japan between 1948 and 1975.

Before it was known as TPS, they simply called it just-in-time manufacturing.

There were 3 things the Toyota Production System attempted to prevent:

• Muda –  Everything in your manufacturing process that creates waste or causes constraints on creating a valuable product.
• Mura – Everything that creates inconsistent and inefficient work flows.
• Muri – All tasks or loads that put too much stress on your employees or machines.

There were also 5 principles that every Lean manufacturing system adhered to:

1. Value – A company delivers the most valuable product to the customer.
2. Value Stream – Map out the steps and processes required to manufacture those valuable products.
3. Flow – Undergo the process of ensuring all of your value-adding steps flow smoothly without interruptions, delays, or bottlenecks.
4. Pull – Products are built on a “just-in-time” basis so that materials aren’t stockpiled and customers receive their orders within weeks, instead of months.
5. Perfection – Make Lean thinking and process improvement a core part of your company culture.

What is Six Sigma?

6 Sigma, or Six Sigma is a data-driven process that seeks to reduce product defects down to 3.4 defective parts per million, or 99.99966{cb377218d5687e54e8ee9149518f87201a393a7c1db5e8076e9d750029ec0dc3} defect-free products over the long-term.

In other words, the goal is to produce nearly perfect products for your customers.

By using statistical models, Six Sigma practitioners will methodically improve and enhance a company’s manufacturing process until they reach the level of Six Sigma.

In all Six Sigma projects, there are 2 main methods of achieving the same defect-free goals. Below, we detail these 2 methods.

The first and most-used method in Six Sigma is a 5-step process called DMAIC:

• Define
• Measure
• Analyze
• Improve
• Control

The DMAIC process uses data and measured objectives to create a cycle of continuous improvement in your manufacturing methods.

While DMAIC is useful for improving your current processes, DMADV is used to develop a new process, product, or service.

DMADV stands for:

• Define
• Measure
• Analyze
• Design
• Verify

The DMADV process uses data and thorough analyses to help you create an efficient process or develop a high-quality product or service.

At their core, Lean and Six Sigma both seek to optimize the manufacturing process in order to provide the highest quality products to their customers. They simply go about it in different ways.

Let’s compare their unique processes for achieving similar goals.

Lean vs Six Sigma: What are Their Differences?

Tools and Philosophy vs Mathematical Models and Statistics

Lean is a philosophy of organizational-wide improvement and a collection of techniques that can be applied in any order to affect organizational change over time. The main focus of which is overall flow and increased productivity along with decreased waste – but without a specified time period for completion.

Six Sigma is a quantitative, mathematical approach to organizational change. Instead of general techniques and principles applied daily and indefinitely, Six Sigma focuses on one aspect of the business and works diligently to improve it before moving on to another aspect of the business.

Continuous Improvement vs Problem-Solving

Lean manufacturing represents a large body of knowledge that insists on continuous, daily improvements, known as the kaizen approach. These improvements can be applied to any piece of equipment, any manufacturing method, and any type of waste throughout the organization.

Six sigma is a problem-solving methodology that uses its collection of tools to fix a specific project over a specific time period. All Six Sigma’s resources are targeted on this one project until the problem is fixed.

While Lean encourages daily, general improvements, Six Sigma demands data-based, specific improvements for specific projects.

Bottom-up Approach vs Top-Down Approach

Lean doesn’t require a hierarchical structure of qualified “masters” to implement the changes. Every individual employee, regardless of their roles in the business is encouraged to participate in actively improving the manufacturing process.

Six sigma requires a hierarchical structure of various experts with various belts, signifying their level of experience and knowledge in the Six Sigma way.

With the Lean approach, you can walk into your factory today and instruct everyone on what to look for and give them methods for applying changes they see fit.

With Six Sigma, you’ll have to hire a certified expert who will assemble a team, identify a problem, and direct that team until the problem is solved.

In Lean, you let everyone test and experiment to see what works and what doesn’t – a bottom-up approach.

In Six Sigma, you let the qualified professional leading the team decide when you’ve completed the project – a top-down approach.

Lean vs Six Sigma: Which Method Should You Implement?

If you’d rather improve the operations of your organization using the collective power and knowledge of your employees, then Lean is the method for you.

If you’d rather use the guidance of a trained professional to fix certain problems in your organization’s operations, then Six Sigma is the method for you.

Yet, both of these methods offer techniques and strategies that every organization can benefit from.

Since they do have similar goals and complementary features, many companies have integrated these methodologies into one system, known as Lean Six Sigma.

In our next post, we’ll dig into Lean Six Sigma and show you how beneficial it can be to combine these two methodologies into a complete system for total manufacturing improvements.

If you want to go beyond manufacturing improvements and into inventory management improvements, you don’t have to wait for our next post.

We can show you how to optimize that part of your business right now.