7 six sigma tools to improve the performance of a textile/apparel industry | What is six sigma? | What is lean?

What is six sigma?

• Six sigma is nothing but a set of tools. These tools and techniques are used to remove variables and optimize the process. Mainly statistical method is used for six sigma. The target is to make the entire production process as smooth as possible as a result the final product will also be defect-free.

• This was introduced by Bill Smith in 1986 and initially used at Motorola. Later Jack Welch used this tool in his central business strategy at General Electronics in 1995.

• For the proper application of six sigma, specialized personnel is hired by the company. Most importantly, all the employees of the company need to understand the significance of this and it also needs the direct involvement of the high-level management.

What is lean?

Lean is a tool that specifically focuses on reducing and eventually eliminating waste from various processes. The application of lean results in cost-saving which is highly beneficial for the company as it reduces the cost of production of the product.

What is Lean six sigma?

• Lean six sigma is a collaborative tool that cuts down the production cost, improves the quality of the product, saves money, and gives the company a major competitive advantage.

• On one hand, six sigma uses different tools and techniques to improve the processes and on the other hand, lean identifies the waste and eliminates them. As a result, the company saves money and also produces a better product.

Lean six sigma and Toyota production system (TPS):

The inspiration for lean six sigma is the ‘Toyota Production System’. This system was developed between 1948 and 1975 by Eiji Toyoda and Taiichi Ohno. The main objective of TPS is to eliminate:

• Overburden

• Inconsistency

• Waste

Due to the proper application of this system, Toyota quickly becomes one of the most efficient companies in the world.

The Toyota production system is based on two concepts:

1. JIDOKA :

•  According to this concept, in case of any abnormality, the machines must come back to a safe spot. The system must need constant human attention in the initial stage. Constant building and improvement operations are done until the system is proved to be completely safe. 

• Initially, the engineers prepare the entire system manually maintaining all the standards. Then the test run is done and in case of any problem the machines stop immediately and the engineers solve the problem. Then after some time, the system becomes stable and reliable. In this stage, the system is introduced for mass production.

• This ensures that the system is defect-free when mass productions are done.

2. Just in time (JIT):

• This includes the planned elimination of and continuous improvement of productivity. According to this technique, raw material will be procured only when it is needed and the inventory level will also be minimum.

The primary elements of JIT:

• Keep only the required inventory.

• Improve quality to zero defects.

• Reduce lead time by reducing setup time, queue length, and lot size.

• Incrementally revise the operation.

• Accomplish things at minimum cost.

Also read: What is Six Sigma | What is lean six sigma | Six sigma application in textile industry 

Lean six sigma tools:

Various six sigma tools are used for process improvement. Almost all of them are a statistical tool. The most common tools are-

• DMAIC

• DMADV

• 5s

• 7 waste 

• Kaizen

• Pareto chart

• Poka-yoke system

Six sigma tools

1. DMAIC: 

This is one of the most commonly used six sigma tools to solve the problems of the existing products. DMAIC stands for:

D = Define (At first the problem in the product is defined)

M = Measure (Data collection is done for several days to get an idea of the problem)

A = Analyze (The collected data are analyzed to find out what the problem is and what can be the possible solution)

I = Improve (The newfound solution is implemented to improve the product)

C = Control (The process must be monitored and controlled to maintain the new standard).

2. DMADV:

This six sigma tool is used while developing a new product. DMADV stands for:

D = Define (At first define the characteristics of the product)

M = Measure (Measure different dimensions of that product)

A = Analyze (analyze those dimensions to find out the best option)

D = Develop (Develop the new product maintaining all those new characteristics)

V = Verify (Verify those characteristics to make sure the performance of the product has met the standard. 

 

 5S:

• Based on 5 Japanese words that begin with ‘S’, 5s philosophy is based on effective workplace organization and standardizing the work procedures. It is a Japanese concept for housekeeping.

• 5s simplifies the workplace, reduces waste and non-value added activity and thus it improved the overall quality.

What is 5s?

1. Seiri (sort): Remove unnecessary, broken items from the workplace. Get rid of oil, dust, etc. the application of seiri in the office environment includes removing all the files and papers that have no use in the near future. 

A good method for marking the unnecessary items is ‘Red tagging’ where a red tag is placed on the unnecessary items.

2. Seiton (Set in order): Focus on the elements and use an effective storage method.

The questions that should be asked are:

a. What do I need to do my job?

b. Where should I locate these items?

c. How many of these items do I really need?

Separate shelves and different colors for different items can really help to organize things.

3. Seiso (Shine): Clutter and junk clog work area. That’s why the workplace should be thoroughly cleaned. Daily 5-10 minutes of cleaning routine should be established. All the items should be placed back to its original location after use.

4. Seiketsu (Standardize): Once these are all done, the standard should be set and should be followed by all the employees of the organization. Also, all the employees should work together to continuously improve the standard. Frequent audits should be done to check the condition.

5. Shitsuke (Sustain): A commitment from both the management and the employees is needed to maintain the standard. A lot of the companies implement 5s but after a few months, they go back to its previous condition due to lack of commitment. That’s why the new status must be maintained as the standard workplace condition.

7 waste:

• The concept of 7 waste was popular by Womack and Jones in their book “The machine that changed the world”. This book bench-marked different companies all around the world and found that Japanese companies were more efficient and more productive compared to other companies in the world.

• The reason behind the success is, Japanese companies successfully removed the waste from their system. That’s why understanding 7 waste and their removal is extremely important.

The 7 wastes are-  

1. Over-production: Over-production causes waste of time, resources, and manpower.

2. Waiting: It is a very common waste in the factory. Mainly is causes due to improper work distribution or defective machines. Waiting results in a waste of time and manpower.

3. Transportation: Unnecessary movement of the products causes due to the lack of planning. It causes a waste of time and energy.

4. Inventory: Extra inventory due to improper planning causes a waste of money and resources.

5. Motion: Unnecessarily moving products and raw materials from table to table causes waste of manpower and time.

6. Over-processing: Extra processing causes waste of time, resources, and manpower. This is one of the most common wastes in the factories.

7. Defective unit: Any kind of defect in the product leads to rework and causes a waste of time and resources.

Kaizen: 

• Kaizen is a Japanese word where “Kai” means Change and “Zen” means Good. So, kaizen means changing towards betterment.

• Tools used in Kaizen:

1. PM (Productive maintenance) analysis

2. Why analysis

3. Summary of losses

4. Kaizen register.

5. Kaizen summary sheet

• Kaizen tries to thoroughly eliminate 16 major losses from the company. They are-

1. Failure losses

2. Setup losses

3. Cutting blade losses.

4. Startup losses

5. Minor stoppage/idle losses

6. Speed losses

7. Defect/rework losses

8. Scheduled downtime losses

9. Management losses

10. Operating motion losses

11. Line organization loss

12. Logistics loss.

13. Measurement/adjustment loss

14. Energy loss

15. Die, jig, tool breakage loss

16. Yield loss

Pareto chart:

• It is a simple statistical chart. In the 19th century, economist Vilfredo Pareto stated that about 80% of the century’s wealth is occupied by 20% population. This famous observation was later named as the “80-20” rule.

• This theory can be applied to quality control also, where it can be stated that 20% of causes are responsible for 80% of problems.

• Although these are not a strict numerical value. The numbers can be 25-75 or 15-85. In a generalized way, it can be said that few causes are responsible for many problems.

Poka-yoke system:

It is a system that explains that by using simple mechanisms mistakes that are made by the operators can be stopped without the concern by the operators. The term “poka-yoke” was used by Shigeo Shingo in his book “Zero quality control: source inspection and the poka-yoke system”. A poka-yoke device will either prevent a mistake from being made or makes the mistake obvious at a glance.

Example of Poka-yoke system:

Automobile control has a mistake-proofing device to ensure that the key is in the on position before allowing the driver to shift out of the park. The key cannot be removed until the car is in the park.