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140ME9122 Lean Manufacturing – Unit II

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Unit II

Lean Tools and Methodologies

Problem solving tools – Cause and Effect Diagram, Pareto analysis, FMEA, Work cell and

equipment management tools – Process Mapping, Spaghetti diagram, U shaped Layout,

Poke Yoke, Kanban, Andon, SMED, One Piece Flow, Genechi Genbutsu, Milk run, Visual

work place, Quality at the source Methodologies – Pillars of Lean Manufacturing – Just in

Time, Jidoka, 5S, TPM, Six Sigma, DFMA, Kaizen.

2.1. PROBLEM SOLVING TOOLS

The term problem solving is used in many disciplines, sometimes with different

perspectives, and often with different terminologies. Problems can also be classified into

two different types (ill-defined and well-defined) from which appropriate solutions are to be

made. Ill-defined problems are those that do not have clear goals, solution paths, or

expected solution. Well-defined problems have specific goals, clearly defined solution

paths, and clear expected solutions.

Problem solving is used in when products or processes fail, so corrective action

can be taken to prevent further failures. It can also be applied to a product or process prior

to an actual fail event, i.e., when a potential problem can be predicted and analyzed, and

mitigation applied so the problem never actually occurs. Techniques such as Failure Mode

Effects Analysis can be used to proactively reduce the likelihood of problems occurring.

Problem-solving strategies are the steps that one would use to find the problem(s)

that are in the way to getting to one's own goal. In this cycle one will recognize the

problem, define the problem, develop a strategy to fix the problem, organize the

knowledge of the problem cycle, figure out the resources at the user's disposal, monitor

one's progress, and evaluate the solution for accuracy.

2.2. CAUSE AND EFFECT DIAGRAM

Cause and Effect Analysis was devised by professor Kaoru Ishikawa, a pioneer of

quality management, in the 1960s. The technique was then published in his 1990 book,

"Introduction to Quality Control."

The diagrams are known as Ishikawa Diagrams or Fishbone Diagrams (because a

completed diagram can look like the skeleton of a fish).

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Although it was originally developed as a quality control tool, For instance, this can

be used it to:

Discover the root cause of a problem.

Uncover bottlenecks in processes.

Identify where and why a process isn't working.

Fig.2.1. Cause and Effect Diagram

Causes are usually grouped into major categories to identify these sources of

variation. The categories typically include

People: Anyone involved with the process

Methods: How the process is performed and the specific requirements for doing it,

such as policies, procedures, rules, regulations and laws

Machines: Any equipment, computers, tools, etc. required to accomplish the job

Materials: Raw materials, parts, pens, paper, etc. used to produce the final product

Measurements: Data generated from the process that are used to evaluate its quality

Environment: The conditions, such as location, time, temperature, and culture in which

the process operates

Procedure to create Cause and Effect diagram:1. To create a Cause and Effect Diagram, write the problem to be solved as descriptively as

possible on one side of the work space, then draw the "backbone of the fish", as shown

below. The example we have chosen to illustrate is "Missed Free Throws".

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Fig.2.2. Cause and Effect Diagram – Step 1

2. The next step is to decide how to categorize the causes. There are two basic methods:

a) by function, or

B) by process sequence. The most frequent approach is to categorize by function.

In manufacturing settings the categories are often: Machine, Method, Materials,

Measurement, People, and Environment. In service settings, Machine and Method are

often replaced by Policies (high level decision rules), and Procedures (specific tasks).

In this case, the manufacturing functions as a starting point, less Measurement because

there was no variability experienced from measurements.


3. That this is not enough detail to identify specific root causes. There are all many

contributors to a problem, so an effective Cause and Effect Diagram will have many

potential causes listed in categories and sub-categories.

The detailed sub-categories can be generated from either or both of two sources:

Brainstorming by group/team members based on prior experiences.

Data collected from check sheets or other sources.

A closely related Cause & Effect analytical tool is the "5-Why" approach, which

states: "Discovery of the true root cause requires answering the question 'Why?' at least

5 times". Additional root causes are added to the fishbone diagram below:

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4. Cause and Effect Diagram is dependent upon the level of development - moving past

symptoms to the true root cause, and quantifying the relationship between the Primary

Root Causes and the Effect.

5. Analysis to a deeper level by using Regression Analysis Designed Experiments to

quantify. After identify the primary contributors, and hopefully quantify correlation, add that

information to chart, either directly or with foot notes.

2.3. PARETO ANALYSISPareto analysis is a formal technique useful where many possible courses of action

are competing for attention. In essence, the problem-solver estimates the benefit delivered

by each action, then selects a number of the most effective actions that deliver a total

benefit reasonably close to the maximal possible one.

Pareto analysis is a creative way of looking at causes of problems because it helps

stimulate thinking and organize thoughts. However, it can be limited by its exclusion of

possibly important problems which may be small initially, but which grow with time. It

should be combined with other analytical tools such as failure mode and effects

analysis and fault tree analysis for example.

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This technique helps to identify the top portion of causes that need to be addressed

to resolve the majority of problems. Once the predominant causes are identified, then tools

like the Fish-bone Analysis can be used to identify the root causes of the problems.

While it is common to refer to pareto as "80/20" rule, under the assumption that, in

all situations, 20% of causes determine 80% of problems, this ratio is merely a

convenient rule of thumb and is not nor should it be considered immutable law of nature.

The application of the Pareto analysis in risk management allows management to focus on

those risks that have the most impact on the project.

Fig.2.5. Pareto Diagram

Steps to identifying the principal causes using Pareto Analysis:

1. Create a vertical bar chart with causes on the x-axis and count (number of

occurrences) on the y-axis.

2. Arrange the bar chart in descending order of cause importance that is, the cause

with the highest count first.

3. Calculate the cumulative count for each cause in descending order.

4. Calculate the cumulative count percentage for each cause in descending order.

Percentage calculation: {Individual Cause Count} / {Total Causes Count}*100

5. Create a second y-axis with percentages descending in increments of 10 from

100% to 0%.

6. Plot the cumulative count percentage of each cause on the x-axis.

7. Join the points to form a curve.

8. Draw a line at 80% on the y-axis running parallel to the x-axis. Then drop the line at

the point of intersection with the curve on the x-axis. This point on the x-axis

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separates the important causes on the left (vital few) from the less important

causes on the right (trivial many).

Fig.2.6. Pareto Analysis Diagram

Here is a simple example of a Pareto diagram, using sample data showing the

relative frequency of causes for errors on websites. It enables that 20% of cases are

causing 80% of the problems and where efforts should be focussed to achieve the greatest

improvement. In this case, we can see that broken links, spelling errors and missing title

tags should be the focus.

2.4. FMEAFailure modes and effects analysis (FMEA) is a step-by-step approach for

identifying all possible failures in a design, a manufacturing or assembly process, or a

product or service.

“Failure modes” means the ways, or modes, in which something might fail. Failures

are any errors or defects, especially ones that affect the customer, and can be potential or

actual.

“Effects analysis” refers to studying the consequences of those failures.

Failures are prioritized according to how serious their consequences are, how

frequently they occur and how easily they can be detected. The purpose of the FMEA is to

take actions to eliminate or reduce failures, starting with the highest-priority ones. Failure

modes and effects analysis also documents current knowledge and actions about the risks

of failures, for use in continuous improvement. FMEA is used during design to prevent

failures.

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When to use FMEA:

When a process, product or service is being designed or redesigned, after quality function

deployment.

When an existing process, product or service is being applied in a new way.

Before developing control plans for a new or modified process.

When improvement goals are planned for an existing process, product or service.

When analyzing failures of an existing process, product or service.

Periodically throughout the life of the process, product or service

FMEA Procedure:

Fig. 2.7. FMEA format

1. Assemble a cross-functional team of people with diverse knowledge about the process,

product or service and customer needs. Functions often included are: design,

manufacturing, quality, testing, reliability, maintenance, purchasing (and suppliers), sales,

marketing (and customers) and customer service.

2. Identify the scope of the FMEA. Is it for concept, system, design, process or service?

What are the boundaries? How detailed should we be? Use flowcharts to identify the

scope and to make sure every team member understands it in detail.

3. Fill in the identifying information at the top of the FMEA form. Figure 2.7 shows a typical

format. The remaining steps ask for information that will go into the columns of the form.

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4. Determine how serious each effect is. This is the severity rating, or S. Severity is

usually rated on a scale from 1 to 10, where 1 is insignificant and 10 is catastrophic. If a

failure mode has more than one effect, write on the FMEA table only the highest severity

rating for that failure mode.

5. For each failure mode, determine all the potential root causes. Use tools classified

as cause analysis tool, as well as the best knowledge and experience of the team. List all

possible causes for each failure mode on the FMEA form.

6. For each cause, determine the occurrence rating, or O. This rating estimates the

probability of failure occurring for that reason during the lifetime of the scope. Occurrence

is usually rated on a scale from 1 to 10, where 1 is extremely unlikely and 10 is inevitable.

On the FMEA table, list the occurrence rating for each cause.

7. For each cause, identify current process controls. These are tests, procedures or

mechanisms that now have in place to keep failures from reaching the customer. These

controls might prevent the cause from happening, reduce the likelihood that it will happen

or detect failure after the cause has already happened but before the customer is affected.

8. For each control, determine the detection rating, or D. This rating estimates how well the

controls can detect either the cause or its failure mode after they have happened but

before the customer is affected. Detection is usually rated on a scale from 1 to 10, where 1

means the control is absolutely certain to detect the problem and 10 means the control is

certain not to detect the problem (or no control exists). On the FMEA table, list the

detection rating for each cause.

9. (Optional for most industries) Is this failure mode associated with a critical characteristic?

(Critical characteristics are measurements or indicators that reflect safety or compliance

with government regulations and need special controls.) If so, a column labeled

“Classification” receives a Y or N to show whether special controls are needed. Usually,

critical characteristics have a severity of 9 or 10 and occurrence and detection ratings

above 3.

10. Calculate the risk priority number, or RPN, which equals S × O × D. Also calculate

Criticality by multiplying severity by occurrence, S × O. These numbers provide guidance for

ranking potential failures in the order they should be addressed.

11. Identify recommended actions. These actions may be design or process changes to lower

severity or occurrence. They may be additional controls to improve detection. Also note who

is responsible for the actions and target completion dates.

12. As actions are completed, note results and the date on the FMEA form. Also, note new

S, O or D ratings and new RPNs.

2.5. WORK CELL

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A work cell is an arrangement of resources in a manufacturing environment to

improve the quality, speed and cost of the process. Work cells are designed to improve

these by improving process flow and eliminating waste. Lean work cells must be designed

for minimal wasted motion, which refers to any unnecessary time and effort required to

assemble a product. Excessive twists or turns, uncomfortable reaches or pickups, and

unnecessary walking all contribute to wasted motion and may put error

inducing stress upon the operator. Work cells can often be reconfigured easily to allow the

adaptation of the process to fit takt time. This flexibility allows the work content to be

adapted as demand or product mix changes.

Fig. 2.8. Work Cell

A work cell is a work unit larger than an individual machine or workstation but

smaller than the usual department. Typically, it has 3-12 people and 5-15 workstations in a

compact arrangement. An ideal cell manufactures a narrow range of highly similar

products. Such an ideal cell is self-contained with all necessary equipment and resources.

Work cell layouts organize departments around a product or a narrow range of

similar products. Materials sit in an initial queue when they enter the department. Once

processing begins, they move directly from process to process. The result is very fast

throughput. Communication is easy since every operator is close to the others. This

improves quality and coordination. Proximity and a common mission enhance teamwork.

U- Shaped Layout

Fig. 2.8. U shaped Work Cell

2.6. EQUIPMENT TOOLS MANAGEMENT

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Tools have a tendency to be issued from their storage location to the point-of-use

on the shop floor. Once issued and used, the tool may return to its original storage

location, stay at the usage location, remain as a dedicated tool or be discarded. However,

over the course of time, the tool will ideally find its way back to its original issue location.

When that happens, decisions are made concerning its usable condition.

It's reusable as is - return it to a storage location.

It needs reconditioning, so send it out for repair or resharpen it.

It is un-repairable - discard it.

The following ten rules will provide the foundation upon which a successful tool

management system can be built.

1. Control the access to the crib. Put a lock on the door.

2. Organize the storage cabinets, shelves or shoeboxes that are used to store the tooling.

Give the locations names, tags or some sequence of identification - numeric, alphabetical

or both.

3. Insist that all tooling issued and returned be recorded through the system. This insures a

higher degree of accuracy.

4. The crib personnel should know more about how the tooling is issued than anyone else

and can provide information critical to the building of the tool database.

5. Train all tool crib personnel. Provide at least two competent system administrators for

overall system control.

6. Establish guidelines for the return of tools to the crib for rework consideration, for the

scrapping of a tool or to return the tool to its original or used location.

7. Review your purchasing procedures. Hold a joint meeting with all personnel involved in

the requisitioning and purchasing of tooling.

8. Establish rules for defining what are durable tools and if they are expected to be

returned to the tool crib. A suggested guideline could be as follows:

Perishable tools can be consumed by use; i.e., drills, end-mills, taps, carbide

inserts, etc.

Durable tools are generally not consumed by use; i.e., toolholders, collets, dies,

micrometers, fixtures and power tools.

Returnable tools are expected to be returned to the crib after use

Non-returnable tools are not required to be returned to the crib after use or tools

that are permanently assigned to a department/ machine or employee.

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9. Establish rules for reordering perishable and durable tools. A suggested guideline could

be as follows:

For perishable tools - reorder when the total quantity of tools in the crib inventory is

below the defined minimum quantity.

For durable tools - reorder when the total on-hand quantity of tools is below the

defined minimum quantity.

10. Agree on a tool numbering system and stick to it. All tooling items must have a discrete

and individual identification to distinguish one item type from another. Establish a group to

be responsible for the implementation and maintenance of the numbering procedure.

Basic Features for Tool Management

Tool/part number.

Description.

Price.

Quantity requirements.

Where used by shop floor, machines, jobs and users.

Minimum/maximum inventory levels.

Reorder point.

Vendor information.

Lead times.

Custom and standard reports.

Tool storage stations.

Tool issue tracking by employee, date, job and profit center/machine.

Support transactions.

Ease of use.

Process new and regrind tool activities.

Tool tracking cross-reference.

Tool availability.

Status reports.

Ordering reports.

Basic inventory information reports.

History information.

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2.7. PROCESS MAPPINGA process map is a planning and management tool that visually describes the flow

of work. Process maps show a series of events that produce an end result. A process map

is also called a flowchart, process flowchart, process chart, functional process chart,

functional flowchart, process model, workflow diagram, business flow diagram or process

flow diagram. It shows who and what is involved in a process and can be used in any

business or organization and can reveal areas where a process should be improved.

Purpose of process mapping:The purpose of process mapping is for organizations and businesses to improve

efficiency. Process maps provide insight into a process, help teams brainstorm ideas for

process improvement, increase communication and provide process documentation.

Process mapping will identify bottlenecks, repetition and delays. They help to define

process boundaries, process ownership, process responsibilities and effectiveness

measures or process metrics.

One of the purposes of process mapping is to gain better understanding of a

process. The flowchart below is a good example of using process mapping to understand

and improve a process. In this chart, the process is making pasta. Even though this is a

very simplified process map example, many parts of business use similar diagrams to

understand processes and improve process efficiency, such as operations, finance, supply

chain, sales, marketing and accounting.

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Fig. 2.8. Sample Process Mapping

Benefits of process mapping:Process mapping spotlights waste, streamlines work processes and builds

understanding. Process mapping allows to visually communicate the important details of a

process rather than writing extensive directions.

Increase understanding of a process

Analyze how a process could be improved

Show others how a process is done

Improve communication between individuals engaged in the same process

Provide process documentation

Plan projects

Process mapping symbols:Key elements of process mapping include actions, activity steps, decision points,

functions, inputs/outputs, people involved, process measurements and time required.

Basic symbols are used in a process map to describe key process elements. Each process

element is represented by a specific symbol such as an arrow, circle, diamond, box, oval

or rectangle. These symbols come from the Unified Modeling Language or UML, which

is an international standard for drawing process maps.

Fig. 2.9. Process mapping symbols

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How to create a process map: Step 1: Identify the problem

What is the process that needs to be visualized?

Type its title at the top of the document.

Step 2: Brainstorm activities involved

At this point, sequencing the steps isn’t important, but it may help to remember the

steps needed for the process.

Decide what level of detail to include.

Determine who does what and when it is done.

Step 3: Figure out boundaries

Where or when does the process start?

Where or when does the process stop?

Step 4: Determine and sequence the steps

It’s helpful to have a verb begin the description.

It can show either the general flow or every detailed action or decision.

Step 5: Draw basic flowchart symbols

Each element in a process map is represented by a specific flowchart symbol.

Ovals show the beginning of a process or the stopping of a process.

Rectangles show an operation or activity that needs to be done.

Arrows represent the flow of direction.

Diamonds show a point where a decision must be made.

A parallelogram shows inputs or outputs.

Step 6: Finalize the process flowchart

Review the flowchart with others stakeholders (team member, workers,

supervisors, suppliers, customers, etc.) for consensus.

Types of process mapping:

Activity Process Map: represents value added and non-value added activities in a

process

Detailed Process Map: provides a much more detailed look at each step in the

process

Document Map: documents are the inputs and outputs in a process

High-Level Process Map: high-level representation of a process involving

interactions between Supplier, Input, Process, Output, Customer (SIPOC)

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Rendered Process Map: represents current state and/or future state processes to

show areas for process improvement

Cross-functional Map: separates out the sub-process responsibilities in the

process

Value-Added Chain Diagram: unconnected boxes that represent a very simplified

version of a process for quick understanding

Value Stream Map: a lean-management technique that analyzes and improves

processes needed to make a product or provide a service to a customer.

Work Flow Diagram: a work process shown in “flow” format; doesn’t utilize Unified

Modeling Language (UML) symbols.

2.8. SPAGHETTI DIAGRAMA spaghetti diagram is a visual representation using a continuous flow line tracing

the path of an item or activity through a process. The continuous flow line enables process

teams to identify redundancies in the work flow and opportunities to expedite process flow.

Fig. 2.10. Spaghetti diagram

The diagram in the figure 2.10. reflects a study done by a health department

administrative office. The intent of the study was to identify ways to shorten the walking

time from one activity to another for frequently performed tasks.

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Another benefit of the visual drawing is to highlight major intersection points within

the room. Areas where many walk paths overlap are causes of delay. Waiting is one of

the eight wastes of lean, as is unnecessary motion.

Collaboration of the staff most affected by the current workplace design was a

secondary benefit of creating the spaghetti diagram. The health department quality

improvement coordinator facilitated a brainstorming session to identify areas of congestion

and wasted movement among the office personnel. Focusing on a common goal brought

the team closer together while highlighting the purpose for placement of some work areas.

These diagrams are used to track:

1. Product Flow

2. Paper Flow

3. People Flow

Use a different line type or color for each flow type, or use separate map for each

flow path for more clarity. Creating a Spaghetti Diagram should be done with or by the

operators or those that use the process. Record the path with a pencil and use a

measuring wheel or tape measure to document distances.

STEPS:1) Record the processes on the side and ask questions if not clear on the activity.

2) Start at the beginning of the scope, the start of the first process. Use directional arrows

for the routes that are traced on the paper.

3) Do not leave out any flow movement

4) Record the amount of time within each activity.

5) Shows the areas where materials stops, staged, held, inspected and picked up. Look for

point-of-use opportunities for materials, tools, and paperwork.

6) Record the names of those involved, dates, times, and other relevant information.

7) Calculate the distance, times, shift, starts, stops, to provide baseline performance.

8) Create a separate diagram showing the ideal state of flow for each that eliminates as

much non-value added tasks as possible.

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Fig. 2.10. Spaghetti diagram – Before & After

2.9. U SHAPED LAYOUTGenerally a U-Shaped work area layout that enables workers to easily move from

one process to another in close proximity and pass parts between workers with little effort.

Cellular manufacturing involves the use of multiple "cells" in an assembly line fashion.

Each of these cells is composed of one or multiple different machines which accomplish a

certain task. The product moves from one cell to the next, each station completing part of

the manufacturing process. Often the cells are arranged in a "U-shape" design because

this allows for the overseer to move less and have the ability to more readily watch over

the entire process.

Fig. 2.11. U shape layout

The layout of work cells in a U shape has several advantages:

The IN and OUT are close, allowing visual control and management, according to

the production takt, a single person can handle both the cell input feeding and

output

The shortening of distances allow sharing of work, as well as reduction of

transportation waste

These layouts provide convenient foundation for one piece flow

Communication among team mates in the cell is easier

The work is done inside the U, supplies remain outside

Usually machines and tables are on rollers (if possible) for quick reconfiguration

The floor space is generally fewer with a U cell than stretched line, walk distances

are also reduced.

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2.10. POKE YOKEPoka Yoke or Mistake proofing is a simple technique that developed out of the

Toyota Production system through Jidoka and Autonomation. It is normally a simple and

often inexpensive device that prevents defects from being made or highlights a defect so

that it is not passed to the next operation.

Purpose of Poka Yoke:

To overcome the inefficiencies of inspection through the use of automatic devices

called Poka Yoke, these seek to do three things;

Not accept a defect for the process

Not Create a Defect

Not Allow a Defect to be passed to the next process

Poka Yoke can be categorized as:

Control – they take physical action to prevent a defect

Warning – They sound an alarm or light up to tell us a mistake has been made.

Types of Poka Yoke:

1. Contact Poka Yoke

Fig. 2.12. Contact Poka Yoke

Contact type Poka Yoke devices that have physical shapes that are used to

prevent the use of incorrect components, pins that have to fit into holes from previous

operations and so on, they physically make contact with the product and highlight when a

mistake has been made or physically make it impossible to make the mistake.

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http://leanmanufacturingtools.org/491/autonomation/

http://leanmanufacturingtools.org/489/jidoka/


2. Fixed Value Pokayoke

Fig. 2.13. Fixed Value Poka Yoke

Fixed Value Pokayoke is a method that uses physical and visual methods to

highlight that all components are available in the right quantities and have been used,

sometimes combined with contact style sensors to make them more positive. Pre-dosed

medication in a sachet rather than relying on the user to measure from a larger container.

3. Motion Stop pokayoke

Fig. 2.14. Motion Stop Poka Yoke

Motion Stop Poka yoke device ensures that the correct number of steps have been

taken and possibly also the sequence steps. Example this could be the use of a nut runner

to tighten a specific number of bolts to a required torque. If the correct torque is not

reached of if the operator not tighten all of the bolts the part will not be released to the next

operation.

2.11.KANBANKanban is an inventory-control system to control the supply chain. Taiichi Ohno,

an at Toyota, developed kanban to improve manufacturing efficiency. Kanban is one

method to achieve JIT.

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https://en.wikipedia.org/wiki/Taiichi_Ohno


Kanban became an effective tool to support running a production system as a

whole, and an excellent way to promote improvement. Problem areas are highlighted by

reducing the number of kanban in circulation. One of the main benefits of kanban is to

establish an upper limit to the work in process inventory, avoiding overloading of the

manufacturing system.

Toyota started studying supermarkets with the idea of applying shelf-stocking

techniques to the factory floor. Kanban aligns inventory levels with actual consumption. A

signal tells a supplier to produce and deliver a new shipment when material is consumed.

These signals are tracked through the replenishment cycle, bringing visibility to the

supplier, consumer, and buyer. Kanban uses the rate of demand to control the rate of

production, passing demand from the end customer up through the chain of customer-

store processes.

Fig. 2.15. Kanban system

Toyota has formulated six rules for the application of kanban: Later process picks up the number of items indicated by the kanban at the earlier

process.

Earlier process produces items in the quantity and sequence indicated by the kanban.

No items are made or transported without a kanban.

Always attach a kanban to the goods.

Defective products are not sent on to the subsequent process. The result is 100%

defect-free goods.

Reducing the number of kanban increases the sensitivity.

Types of Kanban systems:

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In a kanban system, adjacent upstream and downstream workstations

communicate with each other through their cards, where each container has a kanban

associated with it. Economic Order Quantity is important. The two most important types of

kanbans are:

Production (P) Kanban: A P-kanban, when received, authorizes the workstation to

produce a fixed amount of products. The P-kanban is carried on the containers that

are associated with it.

Transportation (T) Kanban: A T-kanban authorizes the transportation of the full

container to the downstream workstation. The T-kanban is also carried on the

containers that are associated with the transportation to move through the loop again.

Kanban cards:

Fig. 2.16. Kanban card

Kanban cards are a key component of kanban and they signal the need to move

materials within a production facility or to move materials from an outside supplier into the

production facility. The kanban card is, in effect, a message that signals depletion of

product, parts, or inventory. When received, the kanban triggers replenishment of that

product, part, or inventory. Consumption, therefore, drives demand for more production,

and the kanban card signals demand for more product — so kanban cards help create a

demand-driven system.

It is widely held by proponents of lean production and manufacturing that demand-

driven systems lead to faster turnarounds in production and lower inventory levels, helping

companies implementing such systems be more competitive.

2.12. ANDON

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Andon is a manufacturing term referring to a system to notify management,

maintenance, and other workers of a quality or process problem. The centre piece is a

device incorporating signal lights to indicate which workstation has the problem. The alert

can be activated manually by a worker using a pull cord or button, or may be activated

automatically by the production equipment itself. The system may include a means to stop

production so the issue can be corrected. Some modern alert systems incorporate audio

alarms, text, or other displays.

Fig. 2.17. Anodon

An Andon System is one of the principal elements of the Jidoka quality-

control method as part of the Toyota Production System. Andon gives the worker the

ability, and moreover the empowerment, to stop production when a defect is found, and

immediately call for assistance. Work is stopped until a solution has been found. The alerts

may be logged to a database so that they can be studied as part of a continuous-

improvement program.

The system typically indicates where the alert was generated, and may also

provide a description of the trouble. Modern Andon systems can include text, graphics, or

audio elements. Audio alerts may be done with coded tones, music with different tunes

corresponding to the various alerts, or pre-recorded verbal messages.

Fig. 2.18. Modern Andon systems

2.13. SMED

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https://en.wikipedia.org/wiki/Quality_control

https://en.wikipedia.org/wiki/Quality_control

https://en.wikipedia.org/wiki/Jidoka


Single-Minute Exchange of Die (SMED) is one of the many lean

production methods for reducing waste in a manufacturing process. It provides a rapid and

efficient way of converting a manufacturing process from running the current product to

running the next product. This rapid changeover is key to reducing production lot sizes and

thereby improving flow, reducing production loss and output variability. The phrase "single

minute" does not mean that all changeovers and start ups should take only one minute,

but that they should take less than 10.

Shigeo Shingo, who created the SMED approach, claims that in his data from

between 1975 and 1985 that average setup times he has dealt with have reduced to 2.5%

of the time originally required; a 40 times improvement.

Shigeo Shingo recognizes eight techniques that should be considered in implementing

SMED.

1. Separate internal from external setup operations

2. Convert internal to external setup

3. Standardize function, not shape

4. Use functional clamps or eliminate fasteners altogether

5. Use intermediate jigs

6. Adopt parallel operations

7. Eliminate adjustments

8. Mechanization

Fig. 2.19. SMED - Adopt parallel operations

Seven basic steps to reducing changeover using the SMED system (Fig 2.19):1. OBSERVE the current methodology (A)

24


2. Separate the INTERNAL and EXTERNAL activities (B). Internal activities are those

that can only be performed when the process is stopped, while External activities

can be done while the last batch is being produced, or once the next batch has

started. For example, go and get the required tools for the job BEFORE the

machine stops.

3. Convert (where possible) Internal activities into External ones (C) (pre-heating of

tools is a good example of this).

4. Streamline the remaining internal activities, by simplifying them (D). Focus on

fixings - Shigeo Shingo observed that it's only the last turn of a bolt that tightens it -

the rest is just movement.

5. Streamline the External activities, so that they are of a similar scale to the Internal

ones (D).

6. Document the new procedure, and actions that are yet to be completed.

7. Do it all again: For each iteration of the above process, a 45% improvement in set-

up times should be expected, so it may take several iterations to cross the ten-

minute line.

SMED improvement should pass through four conceptual stages:A) ensure that external setup actions are performed while the machine is still running,

B) separate external and internal setup actions, ensure that the parts all function and

implement efficient ways of transporting the die and other parts,

C) convert internal setup actions to external,

D) improve all setup actions.

Stages of SMED:

25


Fig. 2.19. Stages of SMED

Example of SMED:

Fig. 2.20. Example of SMED

2.14. ONE PIECE FLOW

Fig. 2.20. One piece flow

One-piece flow is a technique used to manufacture components in a cellular

environment. The cell is an area where everything that is needed to process the part is

within easy reach, and no part is allowed to go to the next operation until the previous

operation has been completed. The goals of one piece flow are: to make one part at a time

correctly all the time to achieve this without unplanned interruptions to achieve this without

lengthy queue times.

Basic condition for achieving one-piece flow:i. Processes must be able to consistently produce good product. If there are many quality

issues, one-piece flow is impossible.

ii. Process times must be repeatable as well. If there is much variation, one-piece flow is

impossible.

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iii. Equipment must have very high uptime. Equipment must always be available to run. If

equipment within a manufacturing cell is plagued with downtime, one piece flow will be

impossible.

iv. Processes must be able to be scaled to tact time, or the rate of customer demand. For

example, if tact time is 10 minutes, processes should be able to scale to run at one unit

every 10 minutes.

Implementing one-piece flow:The first step in implementing a one-piece flow cell is to decide which products or

product families will go into the cells, and determine the type of cell: Product-focused or

mixed model.

The next step is to calculate tact time for the set of products that will go into the cell.

Tact time is a measure of customer demand expressed in units of time and is calculated as

follows:

Tact time = Available work-time per shift / Customer demand per shift.

Next, determine the work elements and time required for making one piece. In much

detail, list each step and its associated time. Time each step separately several times and

use the lowest repeatable time. Then, determine if the equipment to be used within the cell

can meet tact time.

Finally, balance the cell and create standardized work for each operator within the

cell. Determine how many operators are needed to meet tact time and then split the work

between operators. Use the following equation:

Number of operators = Total work content / Tact time

The following illustration shows the impact of batch size reduction when comparing batch

and-queue and one-piece flow.

Fig. 2.21. Batch process Vs One piece flow

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2.15. GENCHI GEMBUTSUGenchi gembutsu is a Japanese phrase that translates in English to “go and see for

yourself” is a central tenet of the Toyota Production System.

Key principle in the Toyota Production System

Go and look out for yourself

Facilitates early contact with potential customers

Increase the chance that actual issues and unplanned events will be observed first

hand.

Fig. 2.22. Genchi Gembutsu

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The idea behind genchi gembutsu is that business decisions need to be based on

first-hand knowledge, not the understanding of another person which might be biased,

outdated or incorrect. Problems are best understood and solved where they occur -– for

example, on the factory floor. Rather than looking at information from a distance –- in an

office, for example –- regarding process issues, managers should go see for themselves

what is happening.

2.16. MILK RUN

Fig. 2.23. Milk run

A method to speed the flow of materials between facilities by routing vehicles to

make multiple pick-ups and drop-offs at many facilities. By making frequent pick-ups and

drop-offs with milk-run vehicles connecting a number of facilities rather than waiting to

accumulate a truckload for direct shipment between two facilities, it is possible to reduce

inventories and response times along a value stream. Milk runs between facilities are

similar in concept to material handling routes within facilities.

Fig. 2.24. Milk run - Example

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2.17. VISUAL WORK PLACE

Visual workplace, visual devices are positioned at the point of use, giving

employees instant access to the critical information they need, right when they need it.

Visuals can easily be understood at a glance, eliminating the wasted downtime that had

previously been spent searching, asking, or waiting for information. This model can greatly

improve your productivity, cost, quality, on-time delivery, inventory and equipment

reliability.

Fig. 2.25. Visual Workplace

Visuals reinforce standards and highlight abnormalities. This is especially important

during the initial phase of lean when companies are using concepts such as 5S, Standard

Work, and Total Productive Maintenance to create a base of operational stability.

A continuously improving work environment is a constantly changing one. Gains

from 5S Workplace Organization, Total Productive Maintenance (TPM), Kaizen

(Continuous Improvement) and other lean activities will disappear unless the new best

practices are embedded in the workplace. Visuals ensure lean improvements remain

clearly visible, readily understood, and consistently adhered to long after the kaizen

improvement event is over – and prevent employees from reverting to old habits.

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Visual controls:

Fig. 2.26. Visual Management

Visual controls allow us to communicate without words and share information

without interrupting. It helps to get everyone working together by providing a clear

understanding of what is required at that point in time. Visual controls contribute to the

management of every process in a way that individuals alone are not able to do, by

showing where discrepancies occur. As with many of the lean enterprise principles we

need to put systems in place to easily identify when things are going well so don’t need to

worry about them. This allows us, and our management team, to easily assess the

situation across the factory and know when we need to act, when things are not under

control or an appropriate response is not being undertaken.

2.18. QUALITY AT THE SOURCE

Quality at the source is a lean manufacturing principle which defines that quality

output is not only measured at the end of the production line but at every step of

the productive process and being the responsibility of each individual who contributes to

the production or on time delivery of a product or service.

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In a practical sense it would involve each operator checking his or her own work

before the part/component or product is sent to the next step in the process. This practice

when first implemented within the workforce will be a challenging change to company

culture but will highlight the relevance of the product's or service's conformance to

customer requirements and standards, thus also imparting the importance of quality

standards and customer satisfaction within the workforce.

Implementing Quality at the source:In order to make the cultural shift within an operation's workforce to embrace

quality at the source the following items should be considered:

-Employee understanding of who the customer is and their requirements

-Internal quality audits

-Employee and team awareness of quality standards and benchmarks

-Employee understanding of the customer's intended use of the product or service

-Multi-skilled workforce which can provide support and help in different process steps

-Required tools and technology to identify quality flaws and rectify them in an efficient

manner

-Proper data collection and tracking of quality faults

-Open communication of standards, performance and processes.

The advantages of quality at the source are many, including: better informed

employees, cultural awareness of the importance of quality to the customer, reduction in

rework expenses, reduction in production production waste, improvement in plant and

process OEE, and most importantly he empowerment of employees in achieving the

desired quality standard required by customers.

2.19. PILLARS OF LEAN MANUFACTURING

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http://www.leanmanufacture.net/leanterms/pokayoke.aspx

http://www.leanmanufacture.net/kpi/qualityaudit.aspx


Fig. 2.27. Pillars of Lean

The main pillars of Lean then are Jidoka (Built in Quality) and Just in Time (JIT),

these are supported by the participation of all staff within the company. Every individual is

respected and expected to perform as part of the team to continually improve every aspect

of the business through Kiazen. All of this is focused on satisfying the customers and

making the business a success for everyone.

2.20. JUST IN TIME

Just-In-Time (JIT) is a purchasing and inventory control method in which materials

are obtained just-in-time for production to provide finished goods just-in-time for sale. JIT is

a demand-pull system. Demand for customer output (not plans for using input resources)

triggers production. Production activities are “pulled” not “pushed” into action.

As philosophy, JIT targets inventory as an evil presence that obscures problems

that should be solved, and declares that, by contributing significantly to casts, target

inventories keep a company from being as competitive or profitable as it otherwise might

be.

A just-in-time manufacturing system requires making goods or service only when

the customer, internal or external, requires it. JIT requires better coordination with

suppliers so that materials arrive immediately prior to their use. It reduces or eliminates

inventory and the costs associated with carrying the inventory. It emphasises that workers

immediately correct the system making defective units because they have no inventory.

JIT aims to achieve the following objectives:1. Zero inventory2. Zero breakdowns

33


3. 100% on time delivery4. Elimination of Non value added activities5. Zero defects.

JIT applies to raw materials inventory as well as to work-in-process inventory. The

goals are that both raw materials and work in process inventory are held to absolute

minimums. JIT is used to complement other materials planning and control tools, such as

EOQ and safety stock levels. In JIT system, production of an item does not commence

until the organisation receives an order.

When an order is received for a finished product, productions people give orders

for raw materials. As soon as production is complete to fill the order, production ends. In

theory, in JIT, there is no need for inventories because no production takes place until the

organisation knows that it will sell them. In practice, however, companies using just-in-time

inventory generally have a backlog of orders or stable demand for their products to assure

continued production.

The fundamental objective of JIT is to produce and deliver what is needed, when it

is needed, at all stages of the production process-just-in-time to be fabricated, sub-

assembled, assembled, and dispatched to the customer. Although in practice there are no

such perfect plants, JIT is an ideal and therefore a worthy goal.

The benefits are low inventory, high manufacturing cycle rates, high output per

employee, minimum floor space requirements, minimum indirect labour, and perfect in-

process control. An associated requirement of a successful JIT operation is the pursuit of

perfect quality in order to reduce, to an absolute minimum, delays caused by defective

product units.

2.21. JIDOKAJidoka is about built in quality and encompasses ideas such

as Autonomation which is giving machines the “human touch” so that they can stop when

things are incorrect, also Poka Yoke or mistake proofing to prevent defects being

produced, accepted or passed on.

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http://leanmanufacturingtools.org/494/poka-yoke/




It also encompasses the philosophy of stopping the production line when defects

are discovered, jidoka provides the framework to drive the non-acceptance of problems

and drives continual improvement.

Jidoka is about quality at source, or built in quality; no company can survive

without excellent quality of product and service and jidoka is the route through which this is

achieved.

Lean relies on Jidoka principles across the various tools and gets us to use visual

management techniques to highlight whenever an abnormality occurs for us to take action.

As team leaders, supervisors and managers we need to keep our eyes open as we walk

through our workplace for these abnormalities and follow through on the Jidoka principles;

1. Discover an abnormality

2. STOP

3. Fix the immediate problem

4. Investigate and correct root cause

This principle is not just confined to use within machines through autonomation ; jidoka

is visible in almost every aspect of lean manufacturing when you start to examine it. It is

about building Quality into a process rather than inspecting for it at the end of the process,

inspection still has a place even in Toyota, and despite what people think can still be a

powerful way of preventing defects reaching the customer.

2.22. 5-S

35


Fig. 2.28. 5-S

5S is the name of a workplace organization method that uses a list of

five Japanese words: seiri, seiton, seiso, seiketsu, and shitsuke. Transliterated into Roman

Script, they all start with the letter "S". The list describes how to organize a work space for

efficiency and effectiveness by identifying and storing the items used, maintaining the area

and items, and sustaining the new order. The decision-making process usually comes from

a dialogue about standardization, which builds understanding among employees of how

they should do the work. In some quarters, 5S has become 6S, the sixth element being

safety.

1st S - Sort (Seiri)

Make work easier by eliminating obstacles.

Reduce chances of being disturbed with unnecessary items.

Prevent accumulation of unnecessary items.

Evaluate necessary items with regard to cost or other factors.

Remove all parts or tools that are not in use.

Segregate unwanted material from the workplace.

Define Red-Tag area to place unnecessary items that cannot immediately be disposed

of. Dispose of these items when possible.

Need fully skilled supervisor for checking on a regular basis.

Waste removal.

Make clear all working floor except using material.

2nd S - Set In Order (Seiton)

Arrange all necessary items so that they can be easily selected for use.

Prevent loss and waste of time by arranging work station in such a way that all tooling /

equipment is in close proximity.

Make it easy to find and pick up necessary items.

Ensure first-in-first-out FIFO basis.

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Make workflow smooth and easy.

All of the above work should be done on a regular basis.

Maintain safety.

Place components according to their uses, with the frequently used components being

nearest to the work place.

3rd S - Shine (Seiso)

Clean your workplace on daily basis completely or set cleaning frequency

Use cleaning as inspection.

Prevent machinery and equipment deterioration.

Keep workplace safe and easy to work.

Keep workplace clean and pleasing to work in.

When in place, anyone not familiar to the environment must be able to detect any

problems within 50 feet

4th S - Standardize (Seiketsu)

Standardize the best practices in the work area.

Maintain high standards in workplace organization at all times.

Everything in its right place.

Every process has a standard.

5th S - Sustain (Shitsuke)

Not harmful to anyone.

Also translates as "do without being told".

Perform regular audits.

Training and discipline.

Training is goal-oriented process. Its resulting feedback is necessary monthly.

Self discipline

To maintain proper order

2.23. TPM

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Total Productive Maintenance (TPM) is a system of maintaining and improving

the integrity of production and quality systems through the machines, equipment,

processes, and employees that add business value to an organization.

TPM focuses on keeping all equipment in top working condition to avoid

breakdowns and delays in manufacturing processes.

One of the main objectives of TPM is to increase the productivity of plant and

equipment with a modest investment in maintenance. Total quality management (TQM)

and total productive maintenance (TPM) are considered as the key operational activities of

the quality management system.

In order for TPM to be effective, the full support of the total workforce is required.

This should result in accomplishing the goal of TPM: "Enhance the volume of the

production, employee morale and job satisfaction."

The main objective of TPM is to increase the Overall Equipment Effectiveness of

plant equipment. TPM addresses the causes for accelerated deterioration while creating

the correct environment between operators and equipment to create ownership.

OEE has three factors which are multiplied to give one measure called OEE

Performance x Availability x Quality = OEE

Each factor has two associated losses making 6 in total, these 6 losses are as follows:

Performance = (1) running at reduced speed - (2) Minor Stops

Availability = (3) Breakdowns - (4) Product changeover

Quality = (5) Startup rejects - (6) Running rejects.

The eight pillars of TPM are mostly focused on proactive and preventive techniques

for improving equipment reliability:

1. Autonomous maintenance

2. Planned Maintenance

3. Quality maintenance

4. Kobetsu Kaizen

5. Early Equipment Management

6. Training and Education

7. Safety, Health & Environment

8. Office TPM

With the help of these pillars we can increase productivity.

38


Fig. 2.28. Eight pillars of TPM

39


TPM Pillars Description Advantages

1

Autonomous

Maintenance

Hands operators of

equipment responsibility to

carry out basic maintenance

of equipment

Operators feel responsible

for their machines,

equipment becomes more

reliable

2Planned

Maintenance

Maintenance scheduled

using the historic failure rate

of equipment

Maintenance can be

scheduled when

production activities are

few

3 Quality

maintenance

Quality ingrained in the

equipment so as to reduce

defects

Defect reduction &

consequent profit

improvement

4Kobetsu Kaizen

Use of cross-functional

teams for improvement

activities

Improves problem solving

capabilities of the workers

5Early Equipment

Maintenance

Design of new equipment

using lesson learnt from

previous TPM activities

New equipment achieves

full potential in a shorter

period of time

6

Training & Education

Bridging of the skills and

knowledge gap through

training of all workers

Employees gain the

necessary skills to enable

them solve problems

within the organization

7Health, Safety &

Environment

Providing of an ideal

working environment devoid

of accidents and injuries

Elimination of harmful

conditions & healthy

workforce

8Office TPM

Spread of the principles to

administrative functions

within an organization

Support functions

understand the benefits of

these improvements

Six Big Losses of Production:

In addition to the losses described in the OEE metric, production units experience

six common losses which reduce the productivity of an organization.

By addressing these losses, a total productive maintenance program results in

increased productivity through reduction of wasteful conditions within processes.

The following table shows the six big losses, their relation to OEE and typical examples in

a production facility:

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Big LossesOEE Loss Classification

Examples Remarks

1

Machine

Breakdowns

Downtime

Loss

Fan belt breakage,

tool failures, motor

breakdown

Must be clearly

defined so as not to

confuse with small

stops

2Setup Loss and

Minor

Adjustments

Downtime

Loss

Product change-

over, staff

shortage,

material shortage

SMED is used for

reducing the effects of

this loss

3

Minor StoppagesSpeed

Loss

Inspection, jams,

adjustments,

blocked sensing

devices,

Very short stops (-

5mins) not requiring

technical intervention

4

Slow RunningSpeed

Loss

Poor settings and

alignment

Factors that prevent

the design

capacity/speed from

been achieved

5

Start-up ErrorsQuality

Lossscrap and rework

Occur before the

process starts in

earnest

6Product Defects

Quality

Lossscrap and rework

Occur during the

running of the process

TPM Implementation Steps:

1. PilotingThe first step in implementing the program should start with the identification of a

pilot area. The importance of this approach is that the program will gain more acceptance

and momentum when staff realise the benefits that accrue from its implementation.

2. Restore Equipment Back to Basic ConditionMachines and equipment are returned to their basic condition through a thorough

5S program coupled with autonomous maintenance as discussed above.

3.OEE TrackingOn completion of the preparatory steps of 5S and autonomous maintenance, the

next logical step is to track the Overall Equipment Effectiveness. This data collection is

important so as to identify the biggest causes of downtime on critical machines.

41


4. Reduce Major LossesReducing the major losses based on the data involves:

Selecting a cross-functional team from a wide section of the workforce and should

comprise of all cadres including operators, technical staff as well supervisors

Data analysis of the major losses as collected from the OEE data.

Root cause analysis of why the losses occurred in the first place.

Implementation of suggested solutions within a specified time frame

Verify effectiveness of the implemented solutions through audits

5. Planned MaintenancePlanned maintenance is a very advanced part of the TPM implementation journey

because it happens only after other components have matured enough to be left on their

own and any benefits accruing from the programs have been exhausted.

2.24. SIX SIGMA

Six Sigma (6σ) is a set of techniques and tools for process improvement. It seeks

to improve the quality of the output of a process by identifying and removing the causes of

defects and minimizing variability in manufacturing and business processes. It uses a set

of quality management methods, mainly empirical, statistical methods, and creates a

special infrastructure of people within the organization who are experts in these methods.

Each Six Sigma project carried out within an organization follows a defined

sequence of steps and has specific value targets, for example: reduce process cycle time,

reduce pollution, reduce costs, increase customer satisfaction, and increase profits.

The maturity of a manufacturing process can be described by a sigma rating

indicating its yield or the percentage of defect-free products it creates. A six sigma process

is one in which 99.99966% of all opportunities to produce some feature of a part are

statistically expected to be free of defects (3.4 defective features per million opportunities).

Motorola set a goal of "six sigma" for all of its manufacturing operations, and this goal

became a by-word for the management and engineering practices used to achieve it.

Six Sigma projects follow two project methodologies inspired by Deming's Plan-Do-

Check-Act Cycle. T

These methodologies, composed of five phases each, bear the acronyms DMAIC

and DMADV.

DMAIC is used for projects aimed at improving an existing business process.

DMADV is used for projects aimed at creating new product or process designs.

The DMAIC project methodology has five phases:

42


Fig. 2.29. DMAIC

Define the system, the voice of the customer and their requirements, and the project

goals, specifically.

Measure key aspects of the current process and collect relevant data; calculate the

'as-is' Process Capability.

Analyze the data to investigate and verify cause-and-effect relationships. Determine

what the relationships are, and attempt to ensure that all factors have been

considered. Seek out root cause of the defect under investigation.

Improve or optimize the current process based upon data analysis using techniques

such as design of experiments, poka yoke or mistake proofing, and standard work to

create a new, future state process. Set up pilot runs to establish process capability.

Control the future state process to ensure that any deviations from the target are

corrected before they result in defects. Implement control systems such as statistical

process control, production boards, visual workplaces, and continuously monitor the

process. This process is repeated until the desired quality level is obtained.

The DMADV project methodology, known as DFSS ("Design For Six Sigma"), features five phases:

Fig. 2.30. DMAIC

Define design goals that are consistent with customer demands and the enterprise

strategy.

Measure and identify CTQs (characteristics that are Critical To Quality), measure

product capabilities, production process capability, and measure risks.

Analyze to develop and design alternatives

Design an improved alternative, best suited per analysis in the previous step

43


Verify the design, set up pilot runs, implement the production process and hand it over

to the process owner(s).

2.25. DFMA

DFMA stands for Design for Manufacture and Assembly. DFMA is the combination

of two methodologies; Design for Manufacture, which means the design for ease of

manufacture of the parts that will form a product, and Design for Assembly, which means

the design of the product for ease of assembly.

Fig.2.31.DFMA

DFM is the method of design for ease of manufacturing of the collection of parts

that will form the product after assembly.

DFA is the method of design of the product for ease of assembly. DFA is a tool

used to assist the design teams in the design of products that will transition to productions

at a minimum cost, focusing on the number of parts, handling and ease of assembly.

PRINCIPLES IN DESIGN FOR MANUFACTURING AND ASSEMBLY:1. Minimize number of components. Assembly costs are reduced. The final product is

more reliable because there are fewer connections. Disassembly for maintenance and field

service is easier. Reduced part count usually means automation is easier to implement.

Work-in-process is reduced, and there are fewer inventory control problems. Fewer parts

need to be purchased, which reduces ordering costs.

2. Use standard commercially available components. Design time and effort are

reduced. Design of custom-engineered components is avoided. There are fewer part

numbers. Inventory control is facilitated. Quantity discounts may be possible.

3. Use common parts across product lines. There is an opportunity to apply group

technology. Implementation of manufacturing cells may be possible. Quantity discounts

may be possible.

44


4. Design for ease of part fabrication. Net shape and near net shape processes may be

feasible. Part geometry is simplified, and unnecessary features are avoided. Unnecessary

surface finish requirements should be avoided; otherwise, additional processing may be

needed.

5. Design parts with tolerances that are within process capability. Tolerances tighter

than the process capability should be avoided; otherwise, additional processing will be

required. Bilateral tolerances should be specified.

6. Design the product to be foolproof during assembly. Assembly should be

unambiguous. Components should be designed so they can be assembled only one way.

Special geometric features must sometimes be added to components to achieve foolproof

assembly.

7. Minimize use of flexible components. Flexible components include parts made of

rubber, belts, gaskets, cables, etc. Flexible components are generally more difficult to

handle and assemble.

8. Design for ease of assembly. Part features such as chamfers and tapers should be

designed on mating parts. Design the assembly using base parts to which other

components are added. The assembly should be designed so that components are added

from one direction, usually vertically. Threaded fasteners (screws, bolts, nuts) should be

avoided where possible, especially when automated assembly is used; instead, fast

assembly techniques such as snap fits and adhesive bonding should be employed. The

number of distinct fasteners should be minimized.

9. Use modular design. Each subassembly should consist of five to fifteen parts.

Maintenance and repair are facilitated. Automated and manual assembly are implemented

more readily. Inventory requirements are reduced. Final assembly time is minimized.

10. Shape parts and products for ease of packaging. The product should be designed

so that standard packaging cartons can be used, which are compatible with automated

packaging equipment. Shipment to customer is facilitated.

11. Eliminate or reduce adjustment required. Adjustments are time-consuming in

assembly. Designing adjustments into the product means more opportunities for out-of-

adjustment conditions to arise.

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2.26. KAIZEN

Fig.2.32. Kaizen

The Japanese word kaizen simply means "change for better", with no inherent

meaning of either "continuous" or "philosophy" in Japanese dictionaries or in everyday

use. The word refers to any improvement, one-time or continuous, large or small, in the

same sense as the English word "improvement". Two kaizen approaches have been

distinguished:

flow kaizen;

process kaizen.

The former is oriented towards the flow of materials and information, and is often

identified with the reorganization of an entire production area, even a company. The latter

means the improvement of individual work stands. Therefore, improving the way

production workers do their job is a part of a process kaizen. The use of the kaizen model

for continuous improvement demands that both flow and process kaizens are used,

although process kaizens are used more often to focus workers on continuous small

improvements.

In this model, operators mostly look for small ideas which, if possible, can be

implemented on the same day. Kaizen is a daily process, the purpose of which goes

beyond simple productivity improvement. It is also a process that, when done correctly,

humanizes the workplace, eliminates overly hard work (muri), and teaches people how to

perform experiments on their work using the scientific method and how to learn to spot and

eliminate waste in business processes.

People at all levels of an organization participate in kaizen, from the CEO down to

janitorial staff, as well as external stakeholders when applicable. Kaizen is most commonly

associated with manufacturing operations, as at Toyota, but has also been used in non-

manufacturing environments.

In modern usage, it is designed to address a particular issue over the course of a

week and is referred to as a "kaizen blitz" or "kaizen event". These are limited in scope,

and issues that arise from them are typically used in later blitzes. A person who makes a

46

https://en.wikipedia.org/wiki/Muri_(Japanese_term)


large contribution in the successful implementation of kaizen during kaizen events is

awarded the title of "Zenkai".

The Toyota Production System is known for kaizen, where all line personnel are

expected to stop their moving production line in case of any abnormality and, along with

their supervisor, suggest an improvement to resolve the abnormality which may initiate a

kaizen.

Fig.2.33. PDCA cycle

The cycle of kaizen activity can be defined as: "Plan → Do → Check → Act". This

is also known as, Deming cycle, or PDCA.Another technique used in conjunction with

PDCA is the 5 Whys, which is a form of root cause analysis in which the user asks a series

of five "why" questions about a failure that has occurred, basing each subsequent question

on the answer to the previous. There are normally a series of causes stemming from one

root cause, and they can be visualized using fishbone diagrams or tables. The Five Whys

can be used as a foundational tool in personal improvement, [18] or as a means to create

wealth.

The basic concept is to identify and quickly remove waste. Another approach is that

of the kaizen burst, a specific kaizen activity on a particular process in the value

stream. Kaizen facilitators generally go through training and certification before attempting

a Kaizen project.

Kaizen is continuous improvement that is based on certain guiding principles: Good processes bring good results

Go see for yourself to grasp the current situation

Speak with data, manage by facts

Take action to contain and correct root causes of problems

Work as a team

Kaizen is everybody’s business

And much more!

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https://en.wikipedia.org/wiki/Kaizen#cite_note-18

https://en.wikipedia.org/wiki/File:PDCA-Two-Cycles.svg


One of the most notable features of kaizen is that big results come from many

small changes accumulated over time. However this has been misunderstood to mean that

kaizen equals small changes. In fact, kaizen means everyone involved in making

improvements. While the majority of changes may be small, the greatest impact may be

kaizens that are led by senior management as transformational projects, or by cross-

functional teams as kaizen events.

**********************

Additional Topics:1. Shadow boards

2. Clock chart

**********************

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Review QuestionsPart –A ( 1 Mark)1. Ishikawa Diagrams is also called as ______________________

a. Fishbone Diagrams, b. Process mapping, c. Pareto Diagram, d. Spaghetti diagram

2. A ________________is a visual representation using a continuous flow line tracing the

path of an item through a process.

a. Fishbone Diagrams, b. Process mapping, c. Pareto Diagram, d. Spaghetti diagram

3. ____________ is a technique that developed out of the Toyota Production system

through Jidoka and Autonomation.

a. Kaizen, b. 5S, c.Poka Yoke, d.TPM

4. Kanban is one method to achieve _________ .

a. JIT, b. TPM, c. TQM, d. All the above.

5. The first step of ________ is separation internal from external setup operations

a. TPM, c. Kaizen, c. SMED, d. Anodon

6. Genchi gembutsu means __________

a. Go and see for yourself, b. Safety workplace, c. Continuous improvement,

d. Elimination of waste

7. _________________ is a visual control.

a. Foot printing, b. Stripping, c. shadowing , d. All the above

8. To overcome the inefficiencies of inspection through the use of automatic devices called

________________ .

a. Poka Yoke, b. SMED, c. Anodon, d. DFMA

9. Just-In-Time (JIT) is ____________ system.

a. Push, b. Pull, c. Linear, d. Quick

10. ________ is the sixth ‘S’ of 5-S.

a. Standardize, b. Sustain, c. Safety, d. Security

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11. Everything in its right place is called as _________

a. Sort, b. Simplify, c. Standardize, d. Sustain

12. ________ event is awarded the title of "Zenkai".

a. Lean b. Six sigma c. TPM, d. Kaizen

13. ____________ is used for projects aimed at improving an existing business process.

a. DMADV, b. DMAIC, c. Kaizen, d. TPM

14. ______ is the base of TPM.

a. TQM, b.5S, c. Kaizen, d.Lean

15. Pareto analysis based on ______ rule.

16. _______ work area layout that enables workers to easily move from one process to

another in close proximity and pass parts between workers with little effort.

17.___________ is a step-by-step approach for identifying all possible failures in a design,

a manufacturing or assembly process.

18. ___________ gives the worker the ability, and moreover the empowerment, to stop

production when a defect is found, and immediately call for assistance.

19. Tact time is equal to _______________

20. Overall Equipment Effectiveness is the measurement of _________________

Answers:

1) a. Fishbone Diagrams , 2) d.Spaghetti diagram, 3) c.Poka Yoke, 4) a. JIT,

5) c. SMED, 6) a. Go and see for yourself, 7) d. All the above, 8) a. Poka Yoke, 9)

b. Pull, 10) c. Safety, 11) c. Standardize, 12) d. Kaizen, 13) b. DMAIC, 14) b.5S, 15)

80/20, 16) U , 17) FMEA, 18) Andon, 19) Available work-time / Customer demand, 20)

TPM.

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Part – B (2 Marks)1. List out the various application of Cause and Effect diagram. Discover the root cause of a problem.

Uncover bottlenecks in processes.

Identify where and why a process isn't working.

2. What are the major categories of causes in Cause and Effect diagram? People

Methods

Machines

Materials

Measurements

Environment

3. What is ‘80/20’ rule in Pareto analysis ?Under the assumption of Pareto analysis, in all situations, 20% of causes

determine 80% of problems.

4. When FMEA to be applied in process? When a process, product or service is being designed or redesigned, after quality

function deployment.

When an existing process, product or service is being applied in a new way.

Before developing control plans for a new or modified process.

When improvement goals are planned for an existing process, product or service.

When analyzing failures of an existing process, product or service.

Periodically throughout the life of the process, product or service

5. Define Work cell.A work cell is an arrangement of resources in a manufacturing environment to

improve the quality, speed and cost of the process.

6. What are rules established for reordering tools?

For perishable tools - reorder when the total quantity of tools in the crib inventory is

below the defined minimum quantity.

For durable tools - reorder when the total on-hand quantity of tools is below the

defined minimum quantity.

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7. List out the purpose of process mapping. The purpose of process mapping is for organizations and businesses to improve

efficiency.

Process maps provide insight into a process.

Process mapping will identify bottlenecks, repetition and delays.

The better understanding of a process.

8. Write down any four process mapping techniques. Activity Process Map

Detailed Process Map

Document Map

High-Level Process Map

Rendered Process Map

Cross-functional Map

Value Stream Map

9. Where Spaghetti diagrams are used?Spaghetti diagrams are used to track Product Flow, Paper Flow and People Flow.

10. What is Poka Yoke?Poka Yoke is a simple technique that developed to do three things:

Not accept a defect for the process

Not Create a Defect

Not Allow a Defect to be passed to the next process

11. Compare P & T Kanban.

Production (P) Kanban Transportation (T) Kanban

A P-kanban, when received, authorizes the

workstation to produce a fixed amount of

products.

A T-kanban authorizes the transportation of

the full container to the downstream

workstation

The P-kanban is carried on the containers

that are associated with it.

The T-kanban is also carried on the

containers that are associated with the

transportation to move through the loop

again.

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12.List out various Andon systems.Andon systems can include text, graphics, or audio elements. Audio alerts may be done

with coded tones, music with different tunes corresponding to the various alerts, or pre-

recorded verbal messages.

13. Write down the four conceptual stages of SMED.A) ensure that external setup actions are performed while the machine is still running,

B) separate external and internal setup actions, ensure that the parts all function and

implement efficient ways of transporting the die and other parts,

C) convert internal setup actions to external,

D) improve all setup actions.

14. Compare one piece flow and Queue Batch flow.

15. What is a Visual Work place?A Visual workplace can be Self- ordering, Self- explaning, self-regulating and self-

improving.

16. Write down the objectives of JIT.

1. Zero inventory2. Zero breakdowns3. 100% on time delivery

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4. Elimination of Non value added activities5. Zero defects.

17. Differentiate JIT and Traditional process.

18. What are the four principles of Jidoka?1.Discover an abnormality

2.STOP

3.Fix the immediate problem

4.Investigate and correct root cause

19. List out the 5-S of workplace.1. Sort ,

2. Simplify,

3. Shine,

4. Standardize and

5. Sustain.

20. What are the six bid losses identified in TPM.1 Machine Breakdowns

2 Setup Loss and Minor Adjustments

3 Minor Stoppages

4 Slow Running

5 Start-up Errors

6 Product Defects

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21. List out the steps involved in TPM Implementation.1. Piloting

2. Restore Equipment Back to Basic Condition

3. OEE Tracking

4. Reduce Major Losses

5. Planned Maintenance

22. What is DFMA?DFMA stands for Design for Manufacture and Assembly. DFMA is the combination

of two methodologies; Design for Manufacture, which means the design for ease of

manufacture of the parts that will form a product, and Design for Assembly, which means

the design of the product for ease of assembly.

23. Write down the basic Kaizen guiding principles. Good processes bring good results

Go see for yourself to grasp the current situation

Speak with data, manage by facts

Take action to contain and correct root causes of problems

Work as a team

Part – C:1. Illustrate the procedure to create Cause and Effect diagram.

2. Explain Pareto Diagram with simple sketch.

3. Describe FMEA format and procedure with an example.

4. Illustrate the steps to create a process map with an example.

5. Explain different types of Poka Yoke techniques.

6. Describe ‘Kanban’ system with simple sketch.

7. Explain Seven basic steps to reducing changeover using the SMED.

8. Illustrate pillars of Lean Manufacturing.

9. Explain 5-S principles.10. Describe TPM principles and implementation with suitable example.

11. Explain six sigma methodologies using in Lean manufacturing.

12. Explain the principles in Design for Manufacturing and Assembly.

Assignment – 2 :Prepare a Shadow board using thermocool for keeping the following item: Pen,

Pencil, Eraser, Scale, Bike key, Marker pen and Mobile phone.

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