Lean Manufacturing | Principles, Method, and Tools of Lean Manufacturing | Why Lean tools is important for apparel Industry

Introduction of Lean: Lean is the name of the concept “To do more by using less”. Lean production usually includes never-ending efforts in the design, production, distribution, and customer service processes to reduce or minimization of Waste ("Muda," or whatever activity consumes resources without added value Japanese for waste).

Lean also takes into consideration waste produced by surplus loads (muri) and waste generated by unequal working loads. Working from the customer's perspective, "value" is an action or process that a customer would be willing to pay for.

The Lean Manufacturing philosophy is mainly derived from Toyota Production System and was only labeled as ' lean ' in the 1990s, and thus attempts to reveal the value added through reducing everything else (as it does not increase added value).

Objectives of lean manufacturing: Lean Manufacturing, also known as Lean Production, is a set of tools and methodologies aimed at implementation and the principal objectives are;

1. Lean's aim to eliminate all waste continuously during production. 
2. Lean is aimed at reducing the cost of production.
3. Lean's aim is to boost output.
4. Lean aims at reducing the lead times in production.

Lean manufacturing 

Including the above objectives, it has also some goals for application;

• Defects and wastage: Minimize defects and needless physical waste including the excess use of raw-material inputs, the avoidable defects and reprocessing cost of non-customer-required defective products.
• Cycle Times: Reduce the lead times and the time of production through reduction of waiting periods between stages and preparation period and conversion times of the product/model.
• Inventory levels: Minimize inventory levels, especially in progress between production stages, at all stages of production. The lower stock also implies lower requirements for working capital.
• Labor Productivity: Improve labor productivity, reducing employees ' idle periods and ensuring that employees make the most of their efforts when they work.
• Utilization of equipment and space: Efficiently use equipment and production areas, while reducing downtime of the machine, by eliminating bottlenecks and maximizing production rates via existing equipment.
• Flexibility: Able to produce a more flexible product range with minimum changes over time and costs.
• Output: Unless reduced cycle times, greater worker productivity and bottlenecks elimination and machine inactivity can be achieved, industries are generally able to increase their existing production facilities.
• Overproduction: It prevents overproduction to produce the exact amount that customers need and when they need it.
• Transportation: Remove the movement of materials and information that does not add value to the product.

Principles of Lean Manufacturing: The following may be summarized in the key principles behind Lean Manufacturing:

• Recognition of waste: The very first task is to realize what creates customer value and does not. Every material, feature process that is not necessary from a customer perspective in order to generate value is a waste and should be removed.
• Standard processes: Lean requires the implementation, in the content, sequence, timing but also the outcome of all employees ' actions, of very thorough production directives called the Standard Works. This prevents changes in the performance of workers ' tasks.
• Continuous flow: The Lean targets usually a continued, non-bottleneck, interruptive, departure, backflow or waiting for production flow. If implemented effectively, the cycle time can be decreased by 90 %.
• Pull-production: The production of pulls, which is also known as Just-in-Time (JIT), is only to produce what is necessary. The downstream plant produces only what is downstream of the next working plant at each workstation.
• Quality at the source: Lean's objective is to eliminate defects at source and to carry out a quality check by employees in the in-line production process.
• Continuous improvement: Lean demands perfection through the constant removal of layers of waste as they have been detected. This requires a high degree of participation by employees in the ongoing development process.

Lean Manufacturing tools and techniques:

1.  Quality control Tools.
2. 5S.
3. Just in time.
4. Kanban.
5. Kaizen

1. Quality control tools in the process of lean production:

• Pareto Chart
• Fish Born Diagram
• Histogram
• Control charts
• Scatter Diagram 

2. 5 S System: These 5 tools are used to standardize the workplace.

1. Seri (Sort).
2. Seiton (Straighten).
3. Seiso (Shine).
4. Seiketsu (standardize).
5. Shitsuke (Sustain).

3. Just in time (JIT): This tool is a key tool for the production of LEANs. Instead of defining the PULL Demand model in the previous system, it controls most of the following activities;

• Purchase.
• Production.
• Distribution. 

4. KANBAN:  This is another essential tool for LEAN's production. What is focused mainly on overproduction? Two types of Kanbans exist mainly.

5. Kaizen: Kaizen is the Japanese term used in a business, operations and/or production process to continuously improve. Some of the areas that can greatly benefit kaizen activity and programs include:

• Individual installations and machinery.
• All manufacturing lines.
• Acquisition and utilization of raw materials.
• Use of the laboratory. 
• Processes and tasks of manufacturing.

Importance of Lean manufacturing in the apparel Industry: Basically, Lean is a systematic method of improving production efficiency by reducing unwanted work that waste time without giving more production. The apparel industry is based on the product manufacturing industry. So it has lots of working process to produce any type of apparel or garments. But the manufacturing process is not the same for all types of product. Some of the processes should be reduced to increase the production rate.

Lean is mostly applicable in those industries has lots of assemblies and have many repetitive working processes. As the garments industry have many assemblies and repetitive work, so lean manufacturing tools and technique has very importance in the apparel industry.

In the past, there are so many problems faced in the apparel industry. Unwanted work, bottlenecks, low production, etc. occurred in the industry. But after starting the implementation of lean all problems is solved like;

• Lean manufacturing technique eliminates unwanted wastage. 
• It makes the workplace more standard. 
• Its planned machine layout is more effective than before layout. 
• Increasing product quality from the source level to the finished level. 
• Reduce all types of production and overhead cost. 
• It also reduces the lead time that helps in time delivery.

Everything is perfect if we apply lean manufacturing technique in the industry. Some improvement of lean manufacturing technique against traditional manufacturing technique are given below;

Activity	Traditional technique	Lean technique
Inventory level	High level	Low level
Cost of production	High	Low
Bundle size	Low	High
Process waste	High	Low
Product inspection	Sample-based inspection	100% inspection
Work in progress	High	Low
Production type	Stock production	Custom production
Layout	Functional layout	Product layout

So, how we find unwanted processes or works? Lean has the answer to this question and it is very much important for the apparel industry. Now every textile and apparel industry are starting to implement lean manufacturing method and using different tools of that.

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References:
1. Gokulraju, Vigneshwar, Vignesh -  Volume: 03 Issue: 12 | Dec -2016 (IRJET)  "A Case Study on Reducing the Lead Time and Increasing Throughput by using Value Stream Mapping".
2. Production and operation management (text and cases) Author-upendra kachru.

3. Clothing Production management-A.J.CHUTTER.