quality cpm 1

8/4/2019 Quality Cpm 1

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Importance of quality:

Customers will buy and keep on buying. If we produce it efficiently, we will

earn a profit.

This definition gives 4 aspects – 3 are independent and the 4th one is

dependent.

• Productivity

• Cost

• Quality

Of these 3 determinants of profitability, the most significant factor in

determining the long range success or failure of an organization is Quality.

Some of the benefits of good quality of the product and the services

1. Competitive edge2. Reduce cost due to returns, rework or scrap

3. Productivity and Profits

3rd is the outcome of the first two.

4. Generates satisfied customers : Benefits of a satisfied customer is - we

have continued patronage and word-of-mouth advertisement

Not only it earns profit, it also gives good will to the company.

Cost of quality

The cost of ensuring that the job is done right + the cost of not doing the job

right

Cost of conformance + cost of non-conformance.

(prevention & appraisal) + (internal & external defects)

Four Cost Categories Related to quality

Prevention Cost: Cost of planning and executing a project so it is error-freeor within an acceptable error range.

Appraisal Cost: Cost of evaluating processes and their outputs to ensure

quality

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Internal Failure Cost: Cost incurred to correct an identified defect before the

customer receives the product.

Identify the defect – do inspection

Not only we should find the defect, we also need to correct it.

Whatever the cost that we are saying that these are the internal cost is the

cost counted before the customer receives the product.

When the customer starts using it and if he finds there is some problem with

the product

External failure cost is basically the cost when the product has been shipped

to the customer.

External Failure Cost – Cost that relates to all errors not detected and

corrected before delivery to the customer.

This has multiple effects – not only the product is coming back to the

company for rework or whatever it is but it is basically spoiling the image

and good will of the company.

So internal and external failure costs need to be carefully ascertained apart

from the prevention and appraisal costs.

This basically shows that the normal cost of quality distribution when the

quality system is not in place; this means – a company which is not having

any quality process, or quality concept or quality system in place, the 4

components that I mentioned – prevention, appraisal, internal and external

failure cost – this slide basically shows all these aspects

Very little in appraisal, little bit more on prevention – total of appraisal and

prevention cost that is the cost of conformance – the spending is very less –as a result, the internal failure cost and external failure cost are very high.

This says that the company good-will, the company product good will or

company itself good will is not good.

Another figure that we will see is “The Optimum Cost of Quality Distribution

when Quality System is in Place.”

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The appraisal cost and prevention cost is increased. The company is

focusing more on prevention and more on appraisal. The result of these two

basically is the reduction in internal and external failure cost.

Once the internal and external failure costs have been reduced, then the

company focuses on the 3 issues mentioned earlier - productivity, cost and

quality.

Once your scrap, rework etc is reduced, certainly your productivity is

improved, quality is improved and cost is reduced. Once the productivity is

there, quality is there, the profit that the company is going to earn is going

to be much higher than the company which is not having the quality system

in place.

With the background of understanding of cost quality and productivity, let usdiscuss about the evolution of quality.

Evolution of quality

During the early days of manufacturing, an operative’s work was inspected

and a decision made whether to accept or reject it. The focus was just to

accept or reject the products based on the specification. No effort was made

on defect prevention.

This means, total productivity or the total output was based only on

inspection. Inspection is basically an audit tool. It is not building quality into

the product. It is just auditing good or bad.

The product is produced, the inspector inspects and then the inspector says

whether the product is good or bad. Bad product is sent back to

manufacturing for rework or scrap and the good product is delivered to the

customer.

There was no effort in identifying the causes that created the bad producttherefore it was mentioned that there was no effort in defect prevention.

In 1922 statistical theory began to be applied effectively to quality control

In 1924 Shewhart made the first attempt of a modern control chart. However, there

was little use of these techniques in manufacturing companies until the late 1940’s.

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1950 – quality management practices developed rapidly in Japanese plants, and

became a major theme in Japanese management philosophy.

By 1960, quality control and management had become a national preoccupation.

1969, Feigenbaum used the term “total quality” for the first time.

1970, Ishikawa used the term “company wide quality control”

1980, Total Quality Management (TQMI came into existence.

As we move into the 21st century, TQM has developed in many countries into holistic

frameworks, aimed at helping organizations achieve excellent performance,

particularly in customer and business results.

Primary

Concern

View of Quality Emphasis Methods

Inspection Detection A problem to

be solved

Product

uniformity

Gauging and

measuringStatistical

Quality Control

Control A problem to

be solved

Product

uniformity with

fewer

inspections

Statistical tools

Quality

Assurance

Coordainating Proactively

solve problem

Production

chain designed

to prevent

failures

Programs and

systems

Strategic

Quality

Management

Strategic

Impact

Competitive

opportunity

Market and

consumer

needs

Strategic

planning and

goal setting.

We have seen the evolution of quality and the historical perspective. If you see, the

table has been divided into 4 parts.

First as I mentioned, initially, in earlier days of manufacturing, the focus was on the

inspection. There was no effort put in to maintain the quality of the product

regarding the prevention of the defects.

2nd row is statistical quality control, third row is quality assurance and the 4th row is

strategic quality management.

For all these perspectives are identified

1. What are the primary concerns?

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2. What view do they take of quality?

3. What is the emphasis on?

4. What method is used for achieving quality?

If we see the inspection –

During the early phase of manufacturing, in the inspection stage, the primaryconcern was detection – detection of scrap, detection of the defective product or

detection of the defect. Although there is no effort on the prevention aspect, as I

earlier mentioned. The view of quality during that period was that a problem is to

be solved. The emphasis was on product uniformity. Every product that is going

into the hand of customer need to be uniform in all the aspects which means it

should be perfect. Methods used are gauges and different measuring instruments

and based on the gauges, calipers and measuring instruments they used to check

whether the product has been made as per the specification or not. Focus was on

the specification – not on the quality into the design of the product

Statistical quality control – although it had started 1920-24, shewahart made the

first attempt to implement the modern quality control chart but up to 1940 there

was nothing there in the history aspect that people are not utilizing the modern

quality control charts in the manufacturing although during the second world war

these techniques were utilized for the maintain or finding the defects as well as to

go for the corrective actions. That is why you see that the primary concern was

control – means to inspect it and find out the reason for why the product is getting

failed or why we are producing defective products.

So, primary concern has to change from detection to control. View of quality was

the same – A problem to be solved, emphasis was – product uniformity with fewerinspections. The focus was that there should be consistency in the quality of the

product as well as the inspection should be as low as possible and the tools that

they used in maintaining the quality of the product are the statistical tools.

Third stage was the quality assurance and the primary concern was coordination.

Earlier, in the inspection and in the statistical quality control, the focus was totally

on the manufacturing side. What is happening before manufacturing and what is

happening once the product has gone into the hands of customer. That focus is

gone. So, in quality assurance stages, they try to integrate the different aspects of

manufacturing, not only the manufacturing, but manufacturing engineering,purchasing, quality in design section and field installation and commissioning of the

product. So they try to coordinate all the activities of the product life cycle and

what was the view of the quality – proactively solve the problem. Emphasis was on

production chain designed to prevent failures. A production chain is basically any

manufacturing activity in the production cycle that starts from the design. Once

they are not able to put the right quality into the design, you cannot put any effort

to bring the quality into the product. So earlier, people were saying that once it is

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in manufacturing stage, they do the inspection and check the specification – if they

meet the expected standards then ok otherwise no. so they try to integrate the

production chain that is designed to prevent failure. Methods were programs and

systems. People were made aware of what are the benefits of quality what are the

different features of quality by using tools, techniques and the awareness programs.

Finally, the present stage, that is, the strategic quality management stage – primary

concern is the strategic impact. It is not only that we are talking about the good

quality or the bad quality of the product, but what is the long term strategic impact

of the product on the company – not only on the profit but also the good will of the

company. View of the quality in the strategic quality management stage is the

competitive opportunity. So there is a lot of competition going on and just to

survive in the competitive market, focus was on competitive opportunity and the

emphasis is on market and consumer needs. Tailor made solutions are now a days

coming up. People were basically driven by the customer earlier – whatever

products were available, the customers used to take it depending on their

requirement; but now, the demand is basically driven from the customer. Methods

– they use the strategic planning and goal setting.

So, this is an overview of the historical perspective in the evolution of quality

starting from the inspection to the strategic quality management in different

concerns from primary concerns to the methods.

Dimensions of quality

Whatever we are saying about the dimension of quality or about the quality – lets

see what we think of quality? – there are various ways we can think of quality asGarvin has mentioned – he has given 8 dimensions of quality – that different people

see quality in different way. Garwin has mentioned that performance is one of the

aspects or one of the quality characteristics that a person can see only depending

on the customer - he may be thinking of the quality, he may be thinking of the

aesthetics – different points are there – some people think of the specification, some

people focus that the product should perform well.

So the first dimension that garvin has given is performance and the question that

we can ask is the product that we are getting or the product that we are

manufacturing – is it doing the intended job or the required job?

2. Second dimension is the reliability. Sometimes, Not only we talk about the

performance of the product, but we also talk about the reliability. How often the

product fails.

3. Also sometimes we go for durability in conjunction with performance and

reliability – how long the product lasts that is the life of the product.

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4. Serviceability – how easy it is to repair the product if there are some small

failures

5. Aesthetics – what does the product look like?

6. Features – what does the product do? Sometimes not only the performance,reliability and durability of the product are looked at, there are similar products

available in the market – some products are having few features and some

products are having additional features. Whatever additional we are getting –

that appeals to us.

7. Conformance to standards – whether the product meets the specifications.

Sometimes the customer provides the specifications for the product like that the

product needs to have that much tolerance, this much specification or this much

strength etc. whether the product that the customer ordered or the customer

thought initially - whether the product meets the specification as he has

specified

8. Perceived quality – what is the reputation of a company or its products? – that is

the good will. Sometimes we have in our mind that whatever product we are

buying is having good quality or the company’s image basically goes with the

product.

Q- how much does the product cost?

These are the 8 dimensions that depends on the customer that depends on the

person – whether he is looking for 1 dimension, 2 dimensions or all the 8 dimensions

of the product – that he is equally satisfied with the performance, he is equally

satisfied with reliability, serviceability, durability etc. may be sometimes some

persons go only for 1 or 2 dimensions like performance and perceived quality. He isonly looking that the company should have good quality and the product should

perform well. The person may not bother about how long the product lasts. So

depending on the requirement the person can have the different dimension of

quality.

The Eight Dimensions of Quality1 Performance Will the product do the intended job?2 Reliability How often the product fails?3 Durability How long the product lasts?4 Serviceability How easy is it to repair the product?5 Aesthetics What does the product look like?6 Features What does the product do?7 Conformance to standards Whether the product meet the

specifications8 Perceived Quality What is the reputation of a company or its

products?

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And coming to the definition of quality, there are 5 different definitions of quality.

The quality can be defined in 5 different ways.

Definitions of Quality1. Transcendent definition excellence

2. Product-based definition Quantities of product attributes3. User-based definition Fitness for intended use4. Value-based definition Quality vs. price5. Manufacturing-based definition Conformance to specifications

The first definition is the transcendent definition:

1. Transcendent : Excellence in all aspects (in all the dimensions)

The second definition is the product based definition: quantities of product

attributes. The product may be having 1 attribute, 2 attribute, 3 attributedepending on the customer requirement. If the customer is looking for more

attributes, then other definitions may be there.

Third type of definition is basically user-based definition. That is, fitness for use,

fitness for the requirement; whatever I am intending for – whether that product is

fit for use

Fourth is value-based definition. Sometimes, we go for the product, we not only

check for the quality, but also we go for the price. If the price is low, we try to make

the trade-off between the price and quality. Sometimes, we have good features,good quality, good performance but cost are high. In such cases we go for some

other product. Because price is the primary concern, we have to think for another

product. So people can go for the value based definition.

Fifth is the manufacturing based definition: earlier people used to have that is

conformance to specification. Whether the product being manufactured meets the

specifications provided by the designer?

So, these are the 5 different ways that we can define quality. There is no unique

definition. It is an individual perspective – how he looks at quality.

This is a tradition definition that “Quality means fitness for use.” This is given by

Joseph Juran.

Customer –Driven Quality

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“ the totality of features and characteristics of a product or services that bear on its

ability to satisfy stated or implied needs of the customers. (ASQC)”

Customer –Driven Quality as per American Society for Quality control

“ the totality of features and characteristics of a product or services that bear on its

ability to satisfy stated or implied needs of the customers.”

This means – meeting or exceeding customer expectations.

There are different companies that focus on just meeting the customer

expectations. Customer is satisfied, but when you give some additional features,

something extra which the customer was not expecting customer feels delighted in

buying and using the product. There is a difference between meeting and

exceeding customer expectations.

So, when a customer buys a product and he is satisfied with the produce, he is a

satisfied customer. But once you give the product additional features, additional

things that the customer was not expecting that means customer delight.

Customer feels delighted in buying and using the product.

3 aspects of quality:

I earlier mentioned, during quality evolution stages focus was on the inspection in

the manufacturing based definition, I mentioned that the focus is on meeting or

conforming to the specifications.

The 3 aspects of quality in this link I say that all the quality aspects are basically

linked with the quality of conformance, quality of design and quality of

performance.

Quality of design is basically consumer’s perspective.

Quality of Design

Quality of Design: Consumer’s Perspective

The product must be designed to meet the requirement fo the customer.

The product must be designed right first time and every time and while designing

all aspects of customer expectations must be incorporated into the product.

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This definition basically changes the focus. Earlier people were concerned only

about the manufacturing; now people think that instead of looking at the

downstream, i.e., the manufacturing and the subsequent stages, we should look

upstream. When we look upstream, the focus should be on the design. When

marketing persons go for the market survey and contact the customers, they try to

capture what the customers want. They try to capture the voice of the customer. They do it by means of a survey, warenttil cost, customer meeting – when they

meet the customer, customer tells them what they want. These marketing people

then understand what the customer is actually requiring and give the entire detail

to the product design section or to the designer. When the designer designs the

product he takes the customer needs into consideration. For example, customer

needs a product with high strength. As I designer, I recommend the material to be

used that provides the desired strength. Then, when my design goes to the

manufacturing, manufacturing people may say that the material you are

specifying, we don’t have any machine to machining that particular material.

Machining of that material is not possible. May be the possibility is there, whatever

material the designer is suggesting, the purchasing dept. may think that they

cannot buy the material, the material is not available. This is a great mistake ( a

blunder), I must say, the designer usually do – instead of designing all aspects of

manufacturing, they should involve the people from the subsequent downstream

section like purchasing, manufacturing engineering, manufacturing inspection – all

the stages when the product is in the design stage.

So, when the product is in the design stage, whatever they are designing, may be at

that time, purchasing dept. or purchasing function or purchasing manager may say

that this product or the material that we are suggesting will not be available in the

market. May be, the manufacturing person may say that the tolerance that you areproviding, our existing machines can not deliver that same tolerances. So, the

focus is basically that we cannot put right quality back into the product in the

subsequent stages. We should design the quality right into the product that is why

it is mentioned here that the product must be designed to meet the requirements of

the customer. The product must be designed right first time and every time. So,

first time and every time. Every time basically indicates the consistency of our

delivery. While designing all aspects of customer expectations must be

incorporated into the design. All aspects of customer expectations mean the 8

dimension of the product. May be, the customer is looking for performance,

reliability and durability. Whatever the aspects the customer has specified, all theexpectations or all the aspects the customer is expecting must be incorporated into

the product.

Quality of Design

Quality of Design: Consumer’s Perspective

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The factors need to consider while designing the product are:

1. Type of product

2. Cost

3. Profit policy of the company

4. Demand5. Availability of the parts

So, when a designer designs the product, he needs to focus what type of product

he is designing, he should also have the aspect of the cost, i.e., what is the cost the

customer is willing to pay; he also need to know what is the profit policy of the

company; what is the demand? Whether it is one-of-a-type or continuous-demand

type of product? Whether whatever he is designing and whatever parts or

components he is recommending whether those components or parts are available

in the market or not? It is not only restricted to the parts, as I have earliermentioned the material the designer is suggesting whether that type of material is

available in the near by market or available in the country? Also apart from all

these 5 aspects, the designer must also consider the process capabilities of the

manufacturing machines. That sometimes what happens – suppose the designer

gives the tolerance of ±.003 – means up to 3 places after the decimal. When that

product or component goes into manufacturing, they think that the machines

available in the manufacturing area are not capable of producing parts or

components of that thickness or tolerance, i.e. up to 3 decimal places. So, there is

a to and fro movement of the product and the component – when the available

equipment are not capable of producing the desired specifications, the product is

bound to get rejected because it is not meeting customer’s requirements. The

designer must consider all these factors while designing the product.

The next aspect of quality is the quality of conformance. Quality of conformance is

basically the manufacturer’s Perspective. Earlier aspect that I talked about – the

quality of design that is the consumer’s perspective.

quality of conformance

Quality of conformance: Manufacturer’s Perspective.

The product must be manufactured exactly as designed.

The activities involved at this stage include:

1. Defect finding

2. Defect prevention

3. Defect analysis and

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4. Rectification.

In the manufacture’s perspective, we look what the designer has given to the

manufacturing section and whatever the bill of material and whatever the

specification that has been designed at the product design stage finally comes to

the manufacturing section. The product at this stage must be manufactured exactlyas designed. The activities involved at this stage include: defect finding, defect

prevention, defect analysis and rectification. As per the manufacturer’s

perspective, the focus should be – whatever specification is provided at the design

stage, the manufacturing people should provide exactly the same. So, if not,

because of any reason, the tolerance is not meeting the specification, the first step

in the analysis should be the defect finding. After careful finding of defect, why this

is not happening. Once you know the different types of defects, then the control

phenomena starts – how to prevent these defects. Then we need to find out the

reasons and where are the control mechanisms and then we try to prevent all these

defects. This is possible only when we go for the defect analysis. Once we find thedefect, we analyze the defect then only we can prevent it. Not only our process is

to prevent the defect but also rectification in the process. So that the process

performs all the steps necessary to produce the product in the right way first time

and every time.

Quality of conformance in continuation – some of the times the difficulties

encountered at the manufacturing stage must be conveyed to the designers for

modification in design, if any. The two way communication between designer and

manufacturing may help to improve the quality of the product

Refer to the earlier example: designer specifies a tolerance level of ±0.003 and the

manufacturing unit communicates that the existing machines are not capable of

that kind or precision. So the designer tries to find an alternative.

Quality of Performance

The product must function as per the expectations of the customer.

The 2 way communication between designers and customer is the key to have a

quality product.

Three aspects of quality diagram goes here 2-way comm.. bet cust-design and

design-manuf

So, once we have all these 3 aspects, the quality of design, quality of conformance

and the quality of performance – in all these 3 cases, we need 100% perfection.

Our design should be 100% right, our conformance to the specification should be

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100% right and the quality of performance should be 100% right. That means we

should get 10/10, 10/10 & 10/10 in all the 3 aspects of quality.

Then only we say that yes, our product meets the customer’s expectations.

The other definition for quality: earlier we discussed 2 definitions of quality: thefitness for use, quality – what the customer wants or exceeding the customer

requirement

There is another definition of quality which is the modern definition

Quality is inversely proportional to Variability.

This variability means variation – higher the variation, poorer the quality. This

variation will be either from the processes or the product. As far as the processes

are concerned, you need to control the processes. Every process, every machine,

every person – they have inherent variation. This inherent variation basically is theevil that is creating the problem. ISO-9000 is answer to this. It is a total

documented approach. It focuses on that whatever you do you document it and

whatever you have documented, you do it. You follow this and follow it

consistently. Now, the question arises – whatever you are documenting whether

you are documenting right or wrong. If you have documented the wrong

procedures then you are following the wrong procedures consistently. So, that

should not be the approach. Before documenting we need to standardize the

processes, we need to standardize the methods. We should document only the

right methods and the right procedures. Once the procedures have been

standardized, the total documentation should be there and whatever is

documented, we need to practice it.

The focus in ISO-9000 is basically is that irrespective of the person, irrespective of

the system, whosoever does the job, follows the documentation and the quality of

the product is exactly the same as was done before.

This concept of quality that it is inversely proportional to the variation is very well

addressed through the ISO-9000. ISO-9000 focuses on the Quality System

approach as well as on the consistency of the processes.

If we see the traditional and the modern view point of quality (diagram). In thisdiagram, you see that this is the LSL and this is the USL. The traditional approach

was that the customer has given 2 boundaries or 2 conditions that the product we

are manufacturing – it should be between the LSL and USL. Now , suppose the

product that we are manufacturing is near the LSL. Suppose you buy this

product and start using it. In six months time, because of wear and tear, the

dimensions, characteristics of the product goes beyond the LSL. Or, the other way,

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if you purchase the product, that is near to the USL, because of wear & tear and

usage, these characteristics of the product may go beyond the USL.

When the product goes beyond the limits, either LSL or USL, you need to do some

maintenance or rework on this particular characteristic of the product so that it

comes into the specified range mentioned by LSL-USL.

That is the traditional way to looking at the quality. Whenever we put effort to bring

the quality back between the LSL and USL means you are putting extra effort – may

be in terms of money may be in terms of human effort.

So, the modern view point, if you look at the 2nd curve, most of the products are just

near the target. Suppose you buy the product that is towards the left hand side of

this distribution or towards the left tail of the distribution. If you buy this product, it

will take entire life of the product to go beyond the specification limits. When you

use the product, because of wear and tear, when it goes beyond the SLs, entire

lifetime of the product is over. This is basically the difference between the

traditional view point and the modern view point. The traditional view point looks at

the goal point philosophy – even if it is closer to the LSL say pass or fail. But, the

modern view point says that you produce at the target and there is a little variation

around the target. So, this is the concept and this concept clearly supports the

modern definition that is quality is inversely proportional to variation. So, lower the

variation, the better is the quality. And quality improvement is basically a

continuous process. If you keep on reducing the variance, our quality will keep on

increasing. The same concept, the variability concept will continue in the next

lecture and we will build up the situation from the variability concept. We will talk

about different quality control tools and techniques. We will talk about the basic 7quality control tools and then we will talk about all the statistical control charts

ranging from variable to attribute type of charts.

X -- -- X –

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