LEAN SIX SIGMA a Tool to Improve Productivity Quality And

7/29/2019 LEAN SIX SIGMA a Tool to Improve Productivity Quality And

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Khalil IAMOT2006 1 of 7

LEAN SIX SIGMA A tool to Improve Productivity, Quality and

Efficiency in Manufacturing and Industrial Sector

Prof Dr M Shahid Khalil

University of Engineering and Technology Taxila, Pakistan`Email:[email protected]

Prof M Anwer Khan

University of Engineering and Technology Taxila, Pakistan

and

Tariq Mahmood-Student

University of Engineering and Technology Taxila, Pakistan`

Email:[email protected]

1. Abstract:

Lean manufacturing and Six Sigma are two very powerful concepts in manufacturing and

industrial sectors. They have been applied in various forms and have proven their worth in

making businesses more productive over time.

The very latest trend in these fields is to combine the techniques and tools from these two

methodologies into a new format called Lean Six Sigma to improve productivity, quality,

and speed.

This paper will try to capture some of the key concepts in Lean Six Sigma initiatives and how

industries are utilizing it to lower production costs while maintaining high quality and speed.

Various Lean Six Sigma terminologies including Kaizen continuous process improvement,

TAKT Time, Value Stream Mapping (VSM), Jidoka, and Visual Management will be

introduced to give audience an overall idea of this new emerging methodology. Along with

these terminologies, existing Six Sigma tools like Pareto Charts, QFDs and Regression tools

are applied to achieve customer value with minimum waste and maximum profitability.

2. Introduction:

Lean Six Sigma is a relatively new approach in which Six Sigma methodology is practiced toidentify the key Red Xs of the variation and also Lean tools are applied to address the

process of improvement and waste reduction issues all at the same time.

Inherently, Six Sigma methodology focuses on gathering data; analyzing the collected data,

and improving the process yield by using problem solving approach and statistical tools. Six

Sigma mainly focuses on reduction of variation in processes and was unable to address the

waste and speed issues in the processes, which is compensated by the Lean philosophy. Lean

is primarily focused on eliminating or reducing waste and improving the process flow.

Therefore combining these two philosophies certainly leads to better results since they

complement each other. Combining the two, together, Lean Manufacturing and Six Sigma


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become a powerful philosophy to solve problems and reduce the waste and speedup the

process and improve efficiency and process yield.

3. What Is Lean Six Sigma?

Lean Six sigma is a combination of certain tools and techniques to provide Six Sigmapractitioners another philosophy to reduce process and production times while minimizing

the variation and reducing waste at the same time. Lean events and/or projects are relatively

easy to implement in shorter amount of time as compared to Six Sigma projects and thus can

provide quicker results in process improvements.

4. History of Lean:

Lean manufacturing philosophy started in late 1800s from Japan with the concept of

Kaizen. The concept was based on the notion that no product or process can reach a point

where it cannot be improved further. Toyota Company introduced the concepts and tools

related with Lean Manufacturing in 1930s onwards with great success. The philosophy reallytriggered its benefits after World War 2 when Toyota introduced Toyota Production System

(TPS). TPS encapsulates the concepts of Just-In-Time (JIT) and other Lean concepts

including Kaizen and Jidoka. In early 1980s the proper definitions were introduced and by

1990s, Lean Manufacturing and tools showed their impact in various regions including US

manufacturers. In recent years, Lean Manufacturing is getting integrated with Six Sigma to

achieve dramatic improvements and savings in cost, quality and production times.

5. Integrating Six Sigma and Lean:

Integrating Lean tools into Six Sigma process map leads to many benefits. The table shows

the different strengths that each of these philosophies brings to this merger and also gives a

comparison of the two methodologies.

Table 1: Comparison of Lean and Six Sigma.

Lean Six Sigma

Focus and Objective Waste reduction and

flow improvement

Process improvement

and variation reduction

Applicability Mostly manufacturingand supply chain

management

All types of businessprocesses

Process Approach Speedy and focused Discipline of steps

Execution Focus Mainly team focus

(Internal)

Customer focus

(External)

Data Driven Style Quantitative and

qualitative

Mostly Quantitative

Cost of Relatively low Vary based Relatively higher


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As shown by this comparison of the two philosophies that they both have a lot of benefits,which can be integrated, to gain broader benefits. In this paper, some of the Lean principles

and techniques will be discussed which have been successfully utilized in Six Sigma process

map to achieve better results.

6. Kaizen Process Improvement:

The word Kaizen in Japanese language means, Change for the better or continuous

improvement. It is a hands-on process of short duration to develop iterative solutions with

each iteration an improvement on the last. This is the core philosophy of the Lean

Manufacturing so that process and products can be improved on a continuous basis using

various tools. Kaizen is a continuous improvement of a value stream of multiple processes oran individual process to create more value with less waste. There are two levels of Kaizen:

(1) System or Flow Kaizen -- focuses on the overall value stream and

(2) Process Kaizen -- focuses on individual processes.

It is a methodology of continuous cost reduction, quality improvement and delivery time

reduction through shop floor involvement and rapid action. Kaizen is generally practiced as a

continuous series of activities where instances of waste (MUDA) are identified through real -

time and place observation, and eliminated one by one at minimal cost. This is accomplished

through teamwork between workers and managers to pool their wisdom and experience to

increase efficiency in a timely manner. Kaizen normally emphasizes manual work operations

rather than equipment capabilities.

Kaizen must become part of the business culture and understood by everyone in the business

to reap the benefits of lean philosophy.

7. How Lean Tools Integrate In Six Sigma Process Map?

In next few sections we will discuss some of the tools, which can be mapped directly into Six

Sigmas Define/Measure, Analyze, Improve/Optimize and Control process map so that Lean

tools can become part of the practitioners toolkit for better process improvement and

multilateral gains across the board.

Table 2: Tools of Lean & Six Sigma

Implementation on the data,

Solution Approach Process oriented Statistical oriented

Process Map

Phase

Six Sigma Tools Lean Tools

Define/Measure Problem Definition,

Capability Analysis, QFD

Value Stream Mapping (VSM),

TAKT Time, Demand Flow

Analyze Pareto, ANOVA,

Regression

TAKT Time

Improve/Optimize DOE, Simulations Jidoka, VSM, MUDA,


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8. Value Stream Mapping (VSM):

To bring a product from concept to launch and from order to delivery, there are many steps

and processes. Some of the steps or activities transforms or shapes material or information to

meet customer requirements, they are called value added activities or steps and some

activities or steps that take time, resources or space, but do not add to the value of the product

itself are called non-value added activities or steps. Defining and creating a simple diagram

of these steps and activities to see the bigger picture and not the individual components and

processes is called Value Stream Mapping.

In the definition of experts, A Value Stream is all the actions (both value added and non

value added) currently required to bring a product through the main flows essential to every

product: 1) the production flow from raw material into the arms of the customer, and 2) the

design flow from concept to launch. Taking a value stream perspective means working on the

big picture, not just the individual processes, and improving the whole, not just optimizing

the parts.

(Rother and Shook, 1999)

Figure 1

An example Value Stream Mapping: Idea State of a Manufacturing Plant Mapping of each

value added and non-value added step involved in the material and information flows is

called Value Stream Mapping. The process of mapping starts with identification of the value

stream for the product or process, followed by a current-state map provides the current

conditions and state of the activities. Then follows a future state map showing theopportunities for improvement identified in the current-state map to achieve a higher level of

Production Smoothing

(Heijunka)

Control Poke-Yoke, Control

Charts

Visual Management, 5S,

Lean Assessment


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performance in future. These maps are then followed by an implementation plan, which

drives the actions and tasks to move from current state to future state.

There are certain pre-defined icons and representations that are used for value stream

mapping to keep consistency in the maps. Value Stream mapping not only provides a bigger

and whole picture of the process instead of focusing on individual steps, it also exposes thesources of waste, not just the waste itself. It helps to identify the linkages between

information and material flows and thus gives the blueprint for the lean implementation plan.

9. TAKT Time:

TAKT is actually a German word for beat or rhythm. It was first used as a production

management tool in the German aircraft industry in the 1930s. It was the interval at which

aircraft were moved ahead to the next production station. The concept is being widely

utilized within Toyota since 1950s. The purpose of TAKT time is to precisely match

production with demand. It provides the heartbeat of a lean manufacturing system. TAKT

time is the pace at which the customer is buying a particular product or service. Taking theavailable time to work and dividing it by the demand for that same period of time gives

TAKT time.

TAKT Time = Available Production Time per period / Required Production per period

For example, if a widget factory operates 480 minutes per day and customers demand 240

widgets per day, TAKT time is two minutes per widget

Figure 2

TAKT time is not how long it takes to perform a task rather it is dependent on the output

requirements. All cycle times must be within TAKT time for customer demand to be met ontime and operations must be constructed around it. TAKT time is the most important


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measurement in the manufacturing process and one of the three elements of Just-in-Time.

TAKT Time provides the opportunities in the process to improve the process completion

time.

10. Jidoka:

Jidoka is also a Japanese word meaning automation. Jidoka is sometimes called

autonomation, meaning automation with human intelligence or the concept of adding an

element of human judgment to automated equipment. Jidoka means providing machines and

operators the ability to detect an abnormal condition and immediately take appropriate action

based on the detected condition. In doing this, the equipment becomes capable of

discriminating against unacceptable quality, and the automated process becomes more

reliable.

This enables operations to build-in quality at each process and to separate men and machines

for more efficient work. Jidoka is one of the two pillars of the Toyota Production System

(TPS) along with Just-In-Time (JIT). An example of Jidoka can be seen in laser identificationof the defective parts on machines and manufactured parts. In power looms, when the thread

breaks during the working of the machine, the machine is made intelligent using a laser

pointer to detect this failure mode and tie the knot on the thread with high efficiency. This

preventive and smart detection prevents the loss of closing down the whole production line

and also helps in keeping the good quality thread count in the weaving and spinning industry.

11. Visual

Visual Management is another tool provided by Lean to control the after-Kaizen process

improvements. When the normal and abnormal state of production

12. TAKT Time Chart

Improvement and Management:

Operations can be clearly and visually defined, Visual Management is possible. In visual

management, simple tools are used to identify the target state, and any deviance is met

swiftly with corrective action. Several techniques including 5S and Kanban are used for

visual management. 5Ss are the foundation blocks of the Just-In-Time and Lean production.

5S is based on five Japanese words as defined below:

i. Seiri (Organization) means to sort through and sort out. Distinguish between neededand unneeded items. Examples of this include to remove what is not needed in the production

environment, including equipment, documents, fixtures, machines, work benches, computers,

file cabinets and storage shelves

ii. Seiton (Tidiness) means to organize the necessary items close to where they are

needed and in such a way that they any waste or abnormality is apparent. Examples include

to order and organize items locations self explanatory, use of shadow box, simple labeling

and setting limits for quantities in production lines

iii. Seiso (Purity) means to clean. Cleaning is a form of inspection. Ensure that all

equipment, tools and the entire workplace are clean and safe. Examples include eliminationof dust, dirt, oil, scrap paper, broken skids and empty boxes.


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iv. Seiketsu (Cleanliness) when the first few Ss are practiced for a while, a new state of

efficiency is achieved. This becomes permanent by sharing information and following

standards so abnormalities are quickly recognized and eliminated. Examples of this technique

include communication and sharing information between shifts and then sharing information

with suppliers and customers to close the action items and have more linearity of the process.

This is a proactive approach to keep dirt and dust away from the process

v. Shitsuke (Discipline) means to stick to the rules. Shitsuke means making and

maintaining correct procedures a steady habit. This includes sticking to the rules and

promoting positive discipline for keeping the workspace pleasant. This discipline should be

promoted at all levels of management. Checklists and monitoring procedures need to be in

place to practice this technique effectively.

Some other visual control tools and techniques provided by Lean include, Kanban, Andon,

Standard Operations Charts, Production Boards and Defective Items display.

For example, we could have a kanban system for coffee supplies. Once the coffee supply isdown to two bags, the person making coffee drops a card onto the secretary's desk as a signal

to reorder.

13. Conclusion:

Based on the discussions of some basic concepts about Lean Six Sigma, it can be concluded

that Lean and Six Sigma together complement each other very nicely and if utilized in

organizations and companies especially in the manufacturing sector, Lean Six Sigma can

surely improve productivity, quality and speed of the processes. Further industrial work will

be done by the authors to use value stream mapping and other visual tools, such as PERT

(Program Evaluation Review Techniques), to identify the bottle necks for schedules/lead

time, capacity, and cost.

Bibliography

Michael L. George (2004) The Lean Six Sigma Pocket Toolbook: A Quick Reference Guide

to 100 Tools for Improving Quality and Speed

Pete Pande (2001), Larry Holpp What Is Six Sigma?

Thomas Pyzdek (2003), Revised and Expanded Edition, The Six Sigma Handbook: The

Complete Guide for Greenbelts, Blackbelts, and Managers at All Levels,

Craig Gygi Six Sigma for Dummies

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