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International Journal of Mechanical Engineering and Technology (IJMET)

Volume 9, Issue 5, May 2018, pp. 703–716, Article ID: IJMET_09_05_078

Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=9&IType=5

ISSN Print: 0976-6340 and ISSN Online: 0976-6359

© IAEME Publication Scopus Indexed

WHAT CUSTOMERS NEED FROM A PRODUCT

AND WHY PRODUCTS FAIL?

Reena Pant

Research Scholar, BVDUCOE, Pune, India

Dr. Sachin Chavan

Professor, BVDUCOE, Pune, India

Dr. Sachin Shendokar

Professor, BVCOE, Lavale, Pune, India

ABSTRACT

Total Quality Management provides many tools. To know and understand the

demands of the customers Quality Function Deployment is there. Failure Modes and

Effects Analysis helps to understand why products fail and what are the causes.

In this paper Quality Function Deployment is developed for Air Conditioner

subsequent by Failure Modes and Effects Analysis. By developing the House of

Quality for Quality Function Deployment the customers’ requirements for various

characteristics of AC are converted into manufacturers’ how. In Failure Modes and

Effects Analysis, severity for various causes of failures, their possibilities of detection

during design stage and occurrences are found out. These parameters are used for

calculating the Risk Priority Number.

Keywords: Quality Function Deployment, House of Quality, Failure Modes and

Effects Analysis, Risk Priority Number, Air Conditioner

Cite this Article: Reena Pant, Dr. Sachin Chavan and Dr. Sachin Shendokar, What

Customers Need from a Product and Why Products Fail?, International Journal of

Mechanical Engineering and Technology, 9(5), 2018, pp. 703–716.

http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=9&IType=5

1. INTRODUCTION

The customers are life line of any business. They are the people with demand and needs. It is

usual market practice that the customers want user friendly products. What is meant by this

term “User friendly”? Is it stress free interfacing or handling or dependability on the product?

Yes, to some extent it is. When it is interfacing; it is ergonomics, when it is handling; it is

design or anthropometry and when it is dependability means we are talking about quality. The

customers may be or may not know about design or ergonomics or total quality management

but they want satisfaction of using and owning the product. It is expected that the

manufacturers must understand the needs of the customers and consider them in their products

What Customers Need from a Product and Why Products Fail?


and at the same time make their products dependable and reliable for the customers. So, how

the manufacturers go for it and how the reliability is to be increased?

Total Quality Management (TQM) provides us with many tools to understand the needs of

the customers. Quality Function Deployment (QFD), is one of them which facilitates for

converting the customers‟ requirement into a quantitative language understandable by

manufacturers. Failure Mode and Effects Analysis (FMEA) is a tool which helps to identify

various possible causes of failures so that improving upon them, reliability of the product will

increase. Once the causes of failures are identified then their severity, possibilities of

detection and occurrences are identified. Risk Priority Number (RPN) is calculated for each

cause of failure by the multiplication of severity, detection and occurrences.

In this paper the tool of QFD, the House of Quality, is developed for Air Conditioner

(AC) to identify the customers‟ requirements. Then the Failure Mode and Effects Analysis is

done for identifying various causes of failure and to find RPN for them.

2. TOOL 1: QUALITY FUNCTION DEPLOYMENT

2.1. Development of House of Quality for Air Conditioner

House of Quality is the primary planning tool of QFD. Following steps are followed to

develop the House of Quality for AC:

Step 1: Capturing Customer Requirements (What)

Different techniques to capture the requirements of the customers are interviews,

brainstorming and questioning. In this work questioning technique is used and a questionnaire

is developed to know the customers‟ requirements.

Development of Questionnaire

To collect opinion of the customers on the various features of Air Conditioner, questions

related to Design, Ergonomics and Total Quality Management are framed in the

questionnaire. The questionnaire is divided into two parts. The first part deals with the

Background Information of the Customer, like: his Age, and Educational Background, the

Brand of the AC they are using, Years of usage of the AC, etc. The second part of the

questionnaire deals with the Product Information. Many of the customers may not know about

Ergonomics or Total Quality Management or Design. So, to retrieve the information about

these aspects of AC, the questions in the questionnaire are framed in such a simple manner,

that the customers answer them, without being aware that they are answering about the

Ergonomics or the TQM or the principles of design. The second part of questionnaire is again

sub-divided into four attributes.

They are:

Aesthetics

Feel

Quality

Control Features

To elaborate these attributes, various characteristics are defined for them. For example:

for the attribute Aesthetics, characteristics defined are Appearance, Shape, Size, Colour, Look

and Attractiveness, which completely define the Aesthetics.

Customer Survey: The opinion of customers is collected in Mumbai Area. Around one

hundred and fifty questionnaires were distributed for the purpose of customer survey. Some

participants did not return it; some gave opinion of two ACs in one questionnaire. Such

Reena Pant, Dr. Sachin Chavan and Dr. Sachin Shendokar


questionnaires are not considered. In all hundred questionnaires are considered for the study.

The consolidated data of the customer survey in the questionnaire is shown in the following

table no. 1: Table 1 Opinion of the customers

Attribute 1: Aesthetic Characteristics of AC

Very Bad (1) Bad (2) Fair (3) Good (4) Excellent (5)

Appearance 3 22 63 12

Shape 1 3 20 60 16

Size 1 6 31 50 12

Colour 1 4 16 57 22

Look -- 3 26 53 18

Attractiveness 3 3 32 48 14

Attribute 2: Feel Aspects regarding AC

No (1) Less (2) Somewhat (3) Fairly (4) Highly (5)

Confidence 3 5 22 49 19

Pride 5 5 24 42 21

Reliability 2 2 16 48 29

Fun to Use 2 12 18 43 21

Simple to use 2 3 10 43 41

Gives good performance 2 3 15 46 34

Satisfaction of owning 3 3 16 42 36

Satisfaction with respect to

Price

3 3 21 43 30

Attribute 3: Quality Characteristics of AC

Very Bad (1) Bad (2) Fair (3) Good (4) Excellent (5)

Performance 4 14 59 17

Reliability Not Reliable

(1)

Reliable

(2)

Fairly Reliable

(3)

Very Reliable

(4)

Highly

Reliable (5)

4 12 24 47 13

Ease of use Not Easy (1) Less Easy

(2)

Somewhat Easy

(3)

Easy (4) Very Easy (5)

1 4 8 50 37

Safety Not Safe (1) Less Safe

(2)

Somewhat Safe

(3)

Safe (4) Very Safe (5)

2 7 66 25

Durability Not Durable (1) Less

Durable

(2)

Somewhat

Durable (3)

Durable (4) Very Durable

(5)

1 2 16 69 12

Stress while using

the Product

Very Tiring (1) Tiring (2) Somewhat

Tiring (3)

Less Tiring (4) Not Tiring (5)

7 6 34 52

Brochure and

Documentation

Very Bad (1) Bad (2) Fairly Good (3) Good (4) Excellent (5)

1 5 29 53 12

Noise while

operating

Very Noisy (1) Noisy (2) Fairly (3) Silent (4) Very Silent

(5)

9 37 44 10

Vibrations while

operating

Excessive (1) More than

Normal

(2)

Normal (3) Less than

normal (4)

Very Little (5)

6 34 22 35



These attributes and characteristics are used as customer requirements in the House of

Quality. All the attributes, from the questionnaire are used as Primary Customer requirements.

They are represented in the first column of House of Quality, as shown in figure 1 given as

Annexure 1. The Characteristics defining each Attribute in the questionnaire are used as

Secondary Customer requirement. They are shown in the second column of House of Quality

(Annexure 1).

Step 2: Capturing Technical Descriptors (How)

Defining the appropriate technical descriptors requires an evaluation of the customer

requirements. The defined requirements are each looked at in turn and the descriptors, which

may address the requirements, are defined. The questionnaire is designed in such a manner

that the customers answered for four attributes of the product. These attributes are already

discussed in the previous section. So, Design, Ergonomics and TQM are used as the Primary

Technical Descriptors. Various tools of these primary technical descriptors are used as

secondary technical descriptors. For example, for Design as primary technical descriptor,

Design for assembly, Design for manufacturing etc. are taken as secondary technical

descriptors. Primary technical descriptors are shown in the top row and secondary technical

descriptors are shown in the next row of the House of Quality (Annexure 1).

Step 3: Developing a Relationship Matrix between What's and How's.

Every secondary customer requirement is checked with each secondary technical descriptor to

find out how the particular technical descriptor is related to the specific customer requirement.

Depending on the relationship, the value of 9, 3 or 1 is allocated.

For example, the secondary customer requirement, “Appearance” has got “Very Strong”

relationship with secondary technical descriptors like “Design for assembly”, “Design for

manufacturing etc. So, in House of Quality in relationship matrix, the value of “9” is

assigned. For secondary technical descriptor “User friendly” of primary technical descriptor

Attribute 4: Control Features of Air Conditioner

Worse (1) Bad (2) Fair (3) Good (4) Very Good (5)

Appearance of

remote

2 5 23 50 16

Shape of remote 2 8 22 53 12

Colour of Remote 3 5 20 60 8

Size of control

buttons

1 6 27 46 15

Look of control

buttons

2 7 29 42 16

Layout of control

buttons

1 5 26 50 14

Labels marked on

control buttons

2 5 20 52 16

Colour scheme

used to distinguish

control buttons

11 32 37 15

Adequacy of

controls for

different functions

2 6 32 50 6

Ease of operating

controls

1 4 20 47 23



“Ergonomics” value of “3” is assigned, which shows a “Strong Relationship”. For secondary

technical descriptor “Safety” for primary technical descriptor “Quality” value of “1” is

assigned, which is for “Feeble Relationship”. In the similar manner for every secondary

technical descriptor, relationship is found with secondary customer requirement.

Step 4: Quantitative Customer Requirement

In this study the mean value obtained from the customer survey has been used as the

requirement of the customers. An effort has been made to introduce a group decision making

approach. This approach takes into account multiple preference questionnaire and fuses

different expressions into one uniform group decision. So, the qualitative statements of

customers‟ demand are converted into quantitative statements understandable by the

manufacturers. The calculation of customer requirement value is given in the following table

no. 2.

Table 2 Mean value of customer requirement for appearance

Appearance

Sr. No. Response Category Total Score Group

X f f * x

1 Excellent 5 12 60

2 Good 4 63 252

3 Fair 3 22 66

4 Bad 2 3 6

5 Very Bad 1 0 0

Total 100 384

x=S(f *x)/n 3.84

Where X is rating as given in the questionnaire

f is the number of customers who have chosen the particular rate

n is the total number of customers surveyed

f * x is calculated by multiplying the values of respective columns of “f” values and “x”

values. Then their total is obtained. The total value is divided by the responses received in the

particular secondary requirement. This value is shown in the Right-hand side column of

House of Quality (Annexure 1).

Step 5: Calculation of Absolute Weight

To calculate the Absolute Weight, customer requirement values for various characteristics of

different attributes are multiplied by the respective values entered in the Relationship Matrix

developed in step 3. Then the summation of these multiplied values is carried out for the

entire column. For example, for the Secondary Technical Descriptor “Anthropometric data”

Absolute Weight is 594.12. The calculation is as follows:

Step 5.1: From House of Quality (Fig 1), all the Secondary Customer Requirements having

either “Very strong”, or “Strong” or “Feeble” relationship with a particular Secondary

Technical Descriptor are found out.

Step 5.2: For the particular Secondary Technical Descriptor, the Mean value of Customer

Requirement for every secondary customer requirement addressing to the particular secondary

technical descriptor is also taken from the House of Quality (Annexure 1). This data is shown

in table no. 3.



Table 3 Calculation of Customer Requirement

Customer Requirement Technical Descriptors Relationship

Value

Mean value of

Customer

Requirement Primary Secondary Primary Secondary

Aesthetic

Characteristics

Shape

D

E

S

I

G

N

A

N

T

H

R

O

P

O

M

E

T

R

Y

9 3.87

Size 9 3.66

Look 9 3.86

Attractiveness 9 3.67

Feel

Confidence 9 3.78

Pride 3 3.71

Reliability 3 4.03

Fun to use 9 3.72

Simple to use 3 4.21

Quality

Reliability 9 3.64

Ease of use 9 4.21

Safety 9 4.14

Durability 1 3.91

Stress 9 4.32

Control Appearance 3 3.76

Shape 3 3.13

Colour 1 3.71

Size of control

Buttons

9 3.72

Look 3 3.68

Layout 9 3.77

Labels 9 3.79

Colour Scheme 9 3.59

Ease 9 3.92

Step 5.3: To calculate the “Absolute Weight”, first of all Relationship value found in step 5.1,

is multiplied by the Mean value of Customer requirement found in step 5.2. Then the

summation of all calculated values is carried out. This value is the “Absolute Weight” for the

particular Secondary Technical Descriptor. The calculation is shown in the following table no.

4:

Table 4 Calculation of Absolute Weight

Customer

Requirement

Technical

Descriptors

Relationship Value * Customer Requirement Absolute Weight

Aesthetic

Characteristics

Anthropometric

Data

9 (3.87 + 3.66 + 3.86 + 3.67) =135.54

594.12

Feel 9 (3.78 + 3.72)

+3 (3.71 + 4.03 + 4.21) = 103.35

Quality 9 (3.64 + 4.21 + 4.14 + 4.32)

+ 1 (3.91) = 150.7

Control Features 9 (3.72 + 3.77 +3.79 + 3.59 + 3.92)

+ 3 (3.76 + 3.13 + 3.68)

+ 1 (3.71) =204.53

Similarly, the Absolute Weight for all the Secondary Technical Descriptors is calculated.

They are shown in the following table no. 5.



Table 5 Absolute Weight for Technical Descriptors

Sr. No. Technical Descriptor Absolute Weight

1 Design for Manufacturing 594.24

2 Anthropometric Data 594.12

3 Design for Assembly 557.05

4 User Friendly 481.08

5 Accuracy 437

6 Proportion 413

7 Creativity 402

8 Precision 376.44

9 Geometric Design 368

10 Balance 361

11 Rhythm 355

12 Safety 350

13 Form Variation 313.31

14 Silent Operation 304.3

15 Visualization 274.8

16 Efficient Cooling 273

17 Material 241

18 Contrast 212

19 Minimum Maintenance 211.8

20 Display Output 184.36

21 Variety 157

22 Unity 141

23 After Sales Service 124

24 Absorb Current Fluctuations 109.46

These values are given in the bottom line of the House of Quality (Annexure 1).

2.2. Outcome of the House of Quality

Higher values of the secondary technical descriptors indicate that the manufacturers have to

incorporate these aspects more as they are the indicators of the customers‟ needs. The

customers‟ requirements for four attributes and their characteristics, which are primary and

secondary customers‟ requirements, the primary technical descriptors are defined and tools of

them are taken as secondary technical descriptors. For every secondary customer requirement

customer rating is found and for every secondary technical descriptor absolute weight is

calculated. For example, the customer rating for “stress while using the product” is having the

highest value. So the technical descriptors like rhythm, anthropometric data, and silent

operations are to be taken care of while designing the product. The absolute weight for Design

for manufacturing (the technical descriptor) is one of the highest values. It means that

manufacturers have to enhance characteristics like appearance, attractiveness, reliability

performance safety and durability (the customer requirements) in the AC. Hence, QFD gives a

clear idea of the requirements of the users and efficiently convert them into manufacturers‟

language.

Once the customers‟ requirements are established the next step taken in the study is to find

out the various reasons of failure of Air Conditioners. The tool used for the purpose is Failure

Modes and Effects Analysis.



3. TOOL 2: FAILURE MODES AND EFFECTS ANALYSIS

3.1. Development of Failure Modes and Effects Analysis charts for AC

FMEA is an analytical technique (a paper test) that combines the technology and experience

of people in identifying foreseeable failure modes of a product or process and planning for its

elimination. FMEA is designed to assist the engineers to improve the quality and reliability of

design. To begin with the application of FMEA for an AC, the possible failure modes for AC

are recognized.

The possible failures modes for Air Conditioner

The possible failures modes in an Air Conditioner are

Refrigeration System

Condensed Air

Evaporator

General

Electrical Systems

System/Sub system selected for the study

The study of possible failure modes has helped to identify the system/sub system in which

failure takes place. They are divided into seven categories for the study purposes:

Compressor defects and fan motor defects

Condenser defects

Choked capillary

Starting Capacitor failure

Starting Relay failure

Strainer chocking

Thermostat failure

For these seven categories the data is collected for their failure rates from various service

stations. These service stations undertake the AC repair works. The data is categorized in the

following table no. 6.

Table 6 Data collection from service stations- categorization for FMEA

Components No. of Claims Percent Ranking

Compressor and Fan Motor Defects 289 16.80 2

Condenser Defects 829 48.19 1

Capillary Choked 101 5.87 6

Starting Capacitor failure 136 7.91 4

Starting Relay failure 111 6.45 5

Strainer chocking 197 11.45 3

Thermostat failure 55 3.19 7

Total 1720 100

The data indicates that the highest number of defects occur the Condenser, which is

followed by the Compressor. The failures of strainer are ranked third and likewise other

defects have been allotted the rankings. This ranking is further used as “Occurrence” for the

calculation of Risk Priority Number.



Development of Failure Modes and Effects Analysis chart

For the development of FMEA Chart, for each possible failure mode or defect classified

earlier, the causes of potential failure modes and their effects are recognized. For every cause,

the possibility of “Detection” at the design stage is recognized. Similarly, for every effect the

“Severity” of its happening is found out. The data collected through service station is used as

“Occurrence” of the failure mode. The Risk Priority Number (RPN) is obtained by

multiplying the values of Severity, Detection and Occurrence.

For example, for the component strainer, the chances of detection of the potential cause of

failure, worn out particles is very remote during the design stage, therefore a value of „9‟ is

given to detection. The effect of this cause is choked capillary and it has very high ranking

when potential failure mode affects safe operation and failure occurs with warning. The value

of „9‟ is assigned for such severity. The value of occurrence of failure is „8‟ for the strainer as

per the data collected from the service station. Therefore, RPN is calculated as to be equal to

9*8*9=648. The following tables from table no. 7 to table no. 13 show the FMEA for the

seven components of AC.

Table 7 FMEA for Compressor and Motor

Compressor Motor

Item

Function

Potential

Failure

Mode

Potential

Effects

of

Failure

Seve

rity

(S)

Potential Cause/Mechanism

of Failure

Occurr

ence(O)

Detect

ion(D)

Risk

Priority

Number

(RPN)

Compressor

Motor / To

run

Compressor

Burn Out

Overheat

ing and

burning

smell

9

Continuous Running

9

3 243

No Varnishing of Motor 1 81

Shaft Balance and Bearing

Problem 1 81

Loose Connection 2 162

Low Speed

No

proper

cooling

of the

space

7

Insulation Defects 1 63

No Servicing of Motor 3 189

Fan Capacitor Weak 2 126

Ice

formatio

n on

cooling

coils

7


Fan Capacitor Weak 2 126

Insulation

Compres

sor

current

increases

8


Shaft Balance and Bearing

Problem 1 72

Damage

of

capacitor

and

switch

8

Loose Connection 1 72

Frequent Starting and

Stopping 2 144



Table 8 FMEA for Condenser Defects

Condenser Defects

Item Function

Potential

Failure

Mode

Potential Effects

of Failure S Potential Cause/Mechanism of Failure O D

Risk Priority

Number

(RPN)

To condense

the vapor

refrigerant

Fails to

condense

properly

High Head

Pressure 8

Reduced air quantity

10

6 480

Dirt on coil 6 480

Restricted air inlet and outlet 5 400

Dirty fan blades 7 560

Incorrect rotation of fan 2 160

Poor Installation 8 640

Efficiency Loss 7

Reduced air quantity 6 420

Dirt on coil 6 420





No proper

cooling effect in

the room

7


Dirt on coil 6 420





To transfer

heat from

refrigerant to

air

Condenser

tube

damaged

If leakage

persist,

continuous

running of

compressor

damages the

system

9 Poor Installation 8 720

Efficiency Loss 7


Dirt on coil 6 420





Table 9 FMEA for Capillary Tube

Capillary Tube

Item Function Potential

Failure Mode

Potential

Effects of

Failure

Sever

ity(S)

Potential Cause/Mechanism of

Failure

Occurren

ce(O)

Detectio

n(D)

Risk

Priority

Number

(RPN)

For dropping

pressure of

refrigerant

flowing

through it

Choke up

No gas

flow in

the

capillary 8

Oil in the refrigerant

5

4

160

Compress

or power

will

increase

8

Oil in the refrigerant 4 160

Incorrect selection of Capillary

bore and length 1

40

Ice

formation

on the

capillary

tube

7



bore and length 1

35

Pressure

drop in

the

compresso

r

8



bore and length 1

40



Improper

cooling

effect

7



bore and length 1

35

Leakage in

Capillary

Tube

Compress

or power

will

increase

8



bore and length 1

40

Ice

formation

on the

capillary

tube

7



bore and length 1

35

Pressure

drop in

the

compresso

r

8



bore and length 1

40

Improper

cooling

effect

7



bore and length 1

35

Table 10 FMEA for Starting Capacitor

Starting Capacitor

Item

Function

Potential

Failure Mode

Potential

Effects of

Failure

Sever

ity(S)


Failure

Occurren

ce(O)

Detectio

n(D)

Risk

Priority

Number

(RPN)

To provide

starting

torque to

motor

Fails to

provide

torque

Starting

trouble 8

Fails to provide starting torque

7

5 280

Motor does not start at all 5 280

Fuse blown

out 8

Motor does not start at all 5 280

Motor does

not start at

all

Compressor

does not start

at all

8

Fails to provide starting torque 5 280

Motor windings are weak 6 336

Electrical Problems 8 448

Table 11 FMEA for Starting Relay

Starting Relay

Item

Function

Potential

Failure Mode

Potential

Effects of

Failure

Sever

ity(S)


Failure

Occurren

ce(O)

Detectio

n(D)

Risk Priority

Number

(RPN)

Starting

motor for

running

compresso

r

Relay contact

fails to open

when

compressor

has started

Compressor

motor

winding

becomes

weak 7 Excess load on relay

6

2 84

Formation of

carbon

deposit on

contact

surface

7

Winding of relay gets

overheated. 2 84

Corrosion 4 168

Relay contact

does not close

while

compressor

has started

Relay

contact

melts 8


overheated. 2 96

Continuous

running of

compressor

if contact

fails to open 9

Excess load on relay

2 108

Compressor

may not start 8


overheated. 2 96

Corrosion 4 192



Table 12 FMEA for Strainer

Strainer

Item/Function

Potential

Failure

Mode

Potential

Effects of

Failure

Seve

rity(

S)


Failure

Occurre

nce(O)

Detecti

on(D)

Risk

Priority

Number

(RPN)

To absorb

moisture

Fails to

absorb

moisture

No cooling

effect 8

Too much moisture in

refrigerant

8

5 576

To Collect dust

particles Choke up

Presence of

oil prevents

flow of

refrigerant

9

Dust particles in refrigerant 9 648

Worn out particles from the

compressor parts 9 648

Table 13 FMEA for Thermostat

Thermostat

Item Function

Potential

Failure

Mode

Potential

Effects of

Failure

Seve

rity(

S)

Potential Cause/Mechanism

of Failure

Occurren

ce(O)

Detecti

on(D)

Risk

Priority

Number

(RPN)

To control room

temperature and

accordingly start

and stop

compressor

Contact

Failure

Compressor

runs

Continuousl

y

9

Pitting of contact surfaces

4

3 108

Internal springs get stuck 7 252

Carbon deposits on contact

surface 6 216

Compressor

does not

start at all

8

Circuit Problem 5 160

Arcing results in contact

getting welded 7 224

Improper

Setting

Fails to

control

room

temperature

7

Thermostat not kept in proper

position 9 252

Design Problem 1 28

Circuit Problem 5 140

The RPN value is an indicator of risks which are possible reasons of failure in AC. As

some potential causes/ mechanisms of failures are common for different potential modes

therefore the highest value of RPN is considered in such cases. Some of these values having

RPN more than 400 are given in the following table no. 14.

Table 14 RPN in descending order

Sr. No. Potential cause/Mechanism of Failure RPN

1 Poor Installation 720

2 Worn out particles from the compressor parts 648

3 Dust particles in refrigerant 648

4 Too much moisture in refrigerant 576

5 Dirty fan blades 560

6 Reduced air quantity 480

7 Dirt on coil 480

8 Electrical Problems 448

9 Restricted air inlet and outlet 400

3.2. Outcome of the FMEA

It is observed that poor installation, dust particles in refrigerant, worn out particles from the

compressor part; dirty fan blades etc. are some of the potential causes or mechanism of failure

which have the highest values of RPN. Higher values indicate more concern and attention is

required for the particular potential cause/mechanism of failure of AC. This doesn‟t mean that



lower values can be neglected, but corrective measures to be taken can be ranked lower in

such cases. Sometimes due to improvements carried out for causes of failure of higher values

of RPN, a lower RPN cause gets eliminated.

For example, for the condenser, the potential cause of failure is poor installation with a

possibility of detection at the design stage as “8”. For this potential failure mode is

“condenser tube damage” and effect of failure is “continuous running of the compressor”. It

has a severity of “9”. Therefore, RPN has been calculated as 8*9*10, 10 being the occurrence.

This value is a clear indication that to increase reliability the potential causes and effects

indicated in analysis should be taken care during the design stage only.

4. CONCLUSIONS

Finding the requirements of the customers and converting them into the language understood

by the manufacturers are possible with the help of QFD, a quality tool. When the customers

talk about performance the manufacturer must understand that the customers want efficient

cooling, silent operation as quality aspects and accuracy and precision from ergonomics point

of view and visualization from design aspect are to be considered to enhance the performance.

The house of quality shows all these features.

FMEA has given the values of RPN, indicating the possible failures in the AC. RPN

values are relative measure of the design risks.

Therefore, it can be said that with the help of QFD one can find what customers want and

FMEA will tell why the products fail.

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Effect Analysis on End Milling Process- A Critical Study”, International Journal of

Mechanical Engineering & Technology (IJMET), Volume 4, Issue 5, 2013, pp. 191 - 199,

ISSN Print: 0976 – 6340, ISSN Online : 0976 – 6359.

[4] Abraham Moody K, Vijay Pandey and R.R Lal, Investigation Of Customer Focussed Steel

Plant Product With Quality Function Deployment. International Journal of Mechanical

Engineering and Technology, 8(4), 2017, pp. 1 9– 25.



ANNEXURE 1 HOUSE OF QUALITY

Custo

Appearance 9 9 9 9 3 3 3 3 9 9 3 3 1 9 3 1 3.84

Shape 3 3 9 3 3 3 9 3 9 3 1 3 3.87

Size3 9 3 3 3 9 9 9 3 3 3.66

Colour 9 9 9 9 3 1 9 9 9 3.95

Look 9 9 9 9 3 3 9 9 9 9 9 9 9 1 9 3.86

Attractiveness 9 9 9 9 9 9 3 3 9 9 9 3 9 3 3 9 9 9 1 3.67

Confidence 1 9 3 3 9 1 3 3 9 9 9 3 3.78

Pride 9 3 9 9 3 3 3 3 9 3 3 3 3 3 1 3 9 9 3 3.71

Reliablility 9 9 3 9 3 9 9 1 3 3 9 9 9 3 4.03

Fun to Use 9 9 3 3 9 3 9 9 9 3 3 1 3 3 9 3 3 9 3.72

Simplicity 3 3 9 9 3 9 3 9 1 3 1 9 9 1 4.21

Gives good performance 3 3 3 1 1 9 3 3 9 3 1 3 9 9 9 4.02

Satisfaction 9 9 3 3 1 9 9 3 9 9 9 9 9 1 3 3 9 9 3 4.05

Satisfaction with respect

to Price 9 9 3 1 1 1 1 9 9 3 3 9 3 3 3 3.94

Performance3 3 9 3 9 9 3 3 3 9 3 9 9 3 3.95

Reliability 9 9 3 9 3 3 9 3 1 3 3 9 3 9 3 3.64

Ease of use 3 3 1 1 3 9 3 9 3 1 9 3 9 4.21

Safety 9 9 1 1 3 3 3 3 9 9 9 9 4.14

Durability 9 9 3 9 3 1 9 3.91

Stress while using the

Product 3 3 1 3 9 3 3 9 1 9 1 1 3 1 3 4.32

Noise while operating 9 9 3 9 9 9 3 3 3.55

Vibrations while operating 9 9 1 1 1 1 9 9 3 3 3 3.89

Appearance of remote 9 9 3 9 9 1 3 3 3 3 3 3 3 3.76

Shape of remote3 3 1 1 1 3 3 1 3.13

Colour of Remote 3 1 9 3.71

Size of control buttons 9 9 3 3 9 3 3.72

Look of control buttons 3 3 3 3 3 3 3 3 3 3.68

Layout of control buttons 3 3 9 3 3 3 3 9 3 3 3 3 3.77

Labels marked on control

buttons 3 3 3 9 3 3 3 3 3.79

Colour scheme used to

distinguish control buttons

3 3 9 9 3 1 3.59

Adequacy of controls for

different operations 9 3 3 3.87

Ease of operating control

buttons 9 9 9 3 9 9 9 9 3 9 9 3 3 3 3.92

594.2 557.5 402 368.13 313 275 141 157 355 361 413 212 594.12 273.36 304.3 350 211.8 241 124.44 109.46 482 436.8 376 184

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