Lean Manufacturing vs Six Sigma

Two fundamental methodologies are definitely Lean Manufacturing and Six Sigma for analysing processes and working methods to make them more efficient and effective.

Lean Manufacturing aims to eliminate waste by making the production and logistics flow more efficient and streamlined.

Six Sigma, on the other hand, focuses on reducing defects and improving processes.

Both methods have the same goal, to eliminate waste and create the most efficient system possible, but they differ in their approach and their focus on identifying waste.

Lean Manufacturing

Lean Manufacturing is a way to optimise production, minimising waste, without losing quality.

Lean Manufacturing has existed for a long time and was first implemented at Toyota, becoming one of the most efficient production methods in the world.

This philosophy focuses on 7 areas, identifying waste within the production process:

1. Waits: due to quality problems, line downtime, between production steps and for the parts delivery;
2. Moves: caused by people searching for, picking up and turning the material needed for the assembly or packaging stages;
3. Transport: the use of inappropriate equipment to move parts and products from one workstation to another;
4. Defects: incorrectly oriented assembled parts, lack of adequate equipment on the workstation, components damaged during handling, faulty products reaching the end customer;
5. Inventory: stocks along production lines waiting to be processed, unsold finished products taking up warehouse space;
6. Overproduction: producing before market demands are known, producing only to use machinery and keep operators working;
7. Over-processing: unnecessary processes to assemble a product that do not bring added value.

Using Lean methodology enables manufacturing companies to continuously improve their production process.

By managing each of the 7 areas, companies are able to save time and resources by eliminating activities that do not add value.

In fact, in companies, usually 60 % of the work is waste , 35 % of the activities are non-value-adding but necessary, and only 5 % bring added value.

The ultimate goal is to produce a product or service on time and with a higher quality standard, thus satisfying the consumer.

Six Sigma

Six Sigma methodology deals with reducing defects within production processes, through statistical analysis, by eliminating everything that does not meet the consumer's requirements.

The main goal is to eliminate all activities that do not bring added value for the end customer.

For this purpose, Six Sigma uses two approaches: the DMAIC method and the DMADV method.

DMAIC stands for Define, Measure, Analyse, Improve, and Control, that is:

• Define the problem;
• Measure and quantify the problem;
• Analysing and identifying the cause of the problem;
• Improve, implement and verify the solution adopted;
• Control, monitor and maintain the standards implemented.

This approach fits perfectly in supply chain management problems, or where only minor corrections to the production process are needed and not a totally new method.

DMADV, on the other hand, stands for Define, Measure, Analyse, Design and Verify.?

The initial project phases remain the same, but the design phase consists of creating a completely new solution, and once it has been applied, it is verified whether it actually works.

Lean Manufacturing vs Six Sigma, how do they differ?

Lean Manufacturing and Six Sigma are both methodologies that aim to improve efficiency and quality within organizations. While they have similar goals, they approach them from different angles and have distinct focuses. Here's a comparison of Lean Manufacturing and Six Sigma:

Focus

• Lean focuses on eliminating waste and streamlining processes to maximize value for customers. It aims to create a smooth and efficient flow of materials and information throughout the entire value stream.
• Six Sigma focuses on reducing variation and defects in processes to achieve high-quality outputs. It aims to identify and eliminate sources of variation that cause defects, errors, or inefficiencies.

Goals

• The primary goals of Lean are to increase efficiency, reduce lead times, minimize waste (such as overproduction, waiting time, transportation, defects, etc.), and improve overall customer satisfaction.
• The primary goalss of Six Sigma are to improve quality, reduce defects, enhance process performance, increase customer satisfaction, and achieve statistical control over processes.

Tools and Techniques:

• Lean employs various tools and techniques, including value stream mapping, 5S methodology , kanban systems , just-in-time production , continuous flow, kaizen (continuous improvement), and visual management .
• Six Sigma: Six Sigma utilizes a set of statistical tools and techniques, such as DMAIC (Define, Measure, Analyze, Improve, Control) methodology, statistical process control (SPC), process capability analysis, root cause analysis, design of experiments (DOE), and hypothesis testing.

Scope:

• Lean is a broader methodology that addresses the entire value stream and aims to optimize end-to-end processes, including manufacturing, supply chain, logistics, and administrative functions.
• Six Sigma is primarily focused on process improvement and defect reduction within specific processes or areas, although it can be applied to various departments and functions within an organization.

Cultural Impact:

• Lean promotes a culture of continuous improvement, teamwork, collaboration, and employee empowerment. It emphasizes the involvement of all employees in identifying and eliminating waste.
• Six Sigma encourages a data-driven and analytical culture. It places emphasis on the use of statistical tools and trained professionals known as Black Belts and Green Belts, who lead improvement projects.

Conclusion, which methodology should be used?

If the company involved is looking for a light method to bring innovation, improvement and involvement into processes, Lean might be the ideal solution.

If it is seeking to reduce variability or defects in a more complex environment, Six Sigma might be better suited to solve these critical issues.

Many organisations, however, are now approaching Lean Six Sigma, which combines the principles of Lean Manufacturing and Six Sigma, to improve business processes and results.

This method aims to reduce waste and eliminate errors, using a data-driven approach and a set of statistical tools to identify problem drivers and develop tailor-made solutions.

LEAN Six Sigma aims to achieve significant improvements in quality, efficiency and customer satisfaction by optimising processes and eliminating unnecessary activities.

In particular, Lean Six Sigma focuses on reducing variability and reducing waste, using techniques such as standardisation, cycle time shortening, quality management and statistical analysis.

To implement this methodology, organisations need to train a dedicated team with the necessary skills to guide them towards continuous improvement.

A team that is heterogeneous, consisting of people with experience in both Lean and Six Sigma, but also representatives of the key functions involved in the processes to be improved.

In short, it's up to the company to determine which method best suits its production methods, material types, operators and organisational goals.

Sources

• https://www.purdue.edu/leansixsigmaonline/blog/six-sigma-vs-lean-six-sigma/
• https://smallbusiness.chron.com/lean-manufacturing-vs-six-sigma-43179.html
• https://www.usccg.com/blog/lean-vs-six-sigma-which-methodology-is-better/
• https://www.stephengould.com/lean-manufacturing-vs-six-sigma-which-is-right-for-you/