acknowledgement i

8/2/2019 Acknowledgement i

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ACKNOWLEDGEMENT I

ABSTRACT III

TABLE OF CONTENTS

1 INTRODUCTION 14

1.1 Diploma Thesis 15

1.2 The Company 16

2 FMEA (FAILURE MODE AND EFFECT ANALYSIS) 17

2.1 Background 20

2.2 Types of FMEA 21

2.3 Fundamental ideas of FMEA - why conduct FMEA 23

2.4 Process FMEA 25

3 PERFORMING A PROCESS FMEA 27

3.1 Defining a TEAM 30

3.2 Bill of materials (BOM) 31

3.3 Organization in the productive area 32

3.3.1 Production process of the knitting department 33

3.3.2 Workstation functions within the process 37

3.4 Defect overview 47

3.5 Cause-Effect-Diagrams 58

3.6 Detected defects January-August 2005 68

3.7 Detected defects in the working process 70

3.8 Risk evaluation 75

3.8.1 Severity (SEV) 75


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3.8.2 Occurrence (O)CC 78

3.8.3 Detection (DET) 81

3.8.4 Risk Priority Number (RPN) 85

3.9 Arrangements and solutions 89

3.10 Checking the process - action taken to reduce the defects 102

VI

3.10.1 Which checkups are already planned? 104

3.10.2 RPN new calculation 105

3.11 FMEA form 110

4 CONCLUSION 111

5 REFERENCES. 112

6 APPENDIX 115

6.1 Handbook FMEA 115

6.2 Complete FMEA form 130

VII

LIST OF TABLES

Table 1: BOM 31

Table 2: Defect overview 57

Table 3: Detected defects 2005, January-August 68

Table 4: Detected defects according to the process functions 74

Table 5: Evaluation of severity (SEV) 76

Table 6: Severity of defects 78

Table 7: Evaluation of occurrence (O)CC 79


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Table 8: Occurrence of defects 81

Table 9: Evaluation of detection (DET) 83

Table 10: Detection of defects 84

Table 11: RPN of defects 86

Table 12: Pareto Diagram 87

Table 13: Solutions of defects 91

Table 14: Comparison of defects 2005 106

Table 15: Recalculation of the evaluation of occurrence (O)CC 108

Table 16: Comparison of RPN 109

VIII

LIST OF FIGURES

Figure 1: FMEA Model

Figure 2: Fundamental ideas of FMEA

Figure 3: Brainstorming

Figure 4: The FMEA Process Map

Figure 5: Production Process 1

Figure 6: Production Process 2

Figure 7: Cause-Effect-Diagram: Barr

Figure 8: Cause-Effect-Diagram: Vertical line

Figure 9: Cause-Effect-Diagram: Pinholes

Figure 10: Cause-Effect-Diagram: Centerline

Figure 11: Cause-Effect-Diagram: Lycra thin end

Figure 12: Cause-Effect-Diagram: Pull-out yarn


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Figure 13: Cause-Effect-Diagram: Dropped stitch

Figure 14: Cause-Effect-Diagram: Motes

Figure 15: Cause-Effect-Diagram: Stop marks

Figure 16: Cause-Effect-Diagram: Spandex pulling

Figure 17: Cause-Effect-Diagram: Holes

Figure 18: Cause-Effect-Diagram: Stripes

Figure 19: Cause-Effect-Diagram: Flat appearance

Figure 20: Cause-Effect-Diagram: Contaminated yarn

Figure 21: Cause-Effect-Diagram: Needle breaking the filament

Figure 22: Cause-Effect-Diagram: Heavy Barr

Figure 23: Cause-Effect-Diagram: Spots

Figure 24: Cause-Effect-Diagram: Horizontal broken filament

Figure 25: Diagram: Defects January-August 2005

Figure 26: Pareto Diagram

Figure 27: Diagram: Defects August 2005

Figure 28: Diagram: Defects October 2005

Figure 29: Diagram: Defects December 2005


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Textiles Panamericanos [1995]
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1 INTRODUCTION

The quality of products and processes in the textile industry is very important. Until today the

methods, which are used to analyse and prevent failure modes and effects, are still simple

procedures in the textile industry. Methods for predicting quality assurance are still not verycommon. The FMEA (Failure Mode and Effect Analysis) is an important strategy to analyse and
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prevent potential failures and defects in quality assurance. In other industries like the automotive

industry the FMEA is already an important analysis in the quality management and indispensablefor the production process. The idea of preventing and avoiding failures or defects before the

manufacturing procedure is becoming also an important aspect in the textile industry. Therefore

the FMEA is starting to play a decisive role in the textile production. 2

The FMEA process analyses and evaluates the risks in order to detect and prevent the failures

and defects. It also requests the knowledgebased background of the team members. Theknowledge of the experts in different areas of the process is documented in form of manuals and

an advantage to reduce the failures and defects. The orientation of the FMEA team provides with

internal communication and increases the comprehension in several problems. Safe products andprocesses can improve the development and the production procedure. Conducting FMEA after

the product development does not consider the costs and benefits of the process.

The FMEA method requests consistent realization. It is to be mentioned that the improvementsare not visible immediately. To conduct an effective FMEA, the Company has to integrate the

FMEA in the daily process flow.32cp. Reinecke /Schermbeck [1998]

3cp. http://www.itlocation.com/de/software/prd56770,,.htm [2004]

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1.1 Diploma Thesis

The idea of this thesis APPLYING FMEA IN THE KNITTING PROCESS was developedduring the first month while getting familiar with the production process of the knittingdepartment. By the time of knowing the process and the most known defects during

manufacturing, the author developed the idea of a strategy to apply FMEA (Failure Mode and

Effective Analysis) in the knitting process. FMEA was still not well known for analysing andpreventing potential failures or defects during the manufacturing process. In order to get a better

idea of how to apply the FMEA in the knitting process, the production engineers and the quality

department agreed in some discussions that were taken. The author was in charge of developingan overview of the complete FMEA process in order to know the importance and the procedure

of performing an FMEA. The general idea of this project was to realize and define the basics of

FMEA according to the most important steps for developing an FMEA by showing examples of

the knitting department. These steps should be shown in form of flow charts and examples inorder to give an easier understanding of the procedure. All team members of the FMEA should

study the handbook. The purpose of applying this thesis into the production process of the

knitting department is to improve the quality of the knitting production by reducing the potential

failures and defects. The knitting department can provide a higher quality standard for theircustomers. The FMEA should be integrated in the daily process to provide an effective FMEA.

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1.2 The Company4

Textivisin, located in Tlalnepantla, Estado de Mexico, Mexico, is a textile company, which is

specialised in knitting fabric specifically in synthetic fibres. The company was established in1986. The main customers on the international market are USA, Canada, Europe and SouthAmerica. Furthermore Textivisin is dealing with the national market. The entire production

processes is obtain through international quality standards. The company disposes of a variety of

machines for the knitting, dyeing, printing and finishing procedure. The protection of the

environment is to be considered very seriously. Textivisin has been developed to one of themost important suppliers in the Mexican textile industry, especially in the fabrics, which include

spandex. Taking consideration of the international market, Textivisin imports 20% (raw

material) and exports 80% of their fabrics. The company is in co-operation of three

manufacturing companies divided by areas:

Milltex (knitting) 169 employees

TTM (dyeing, finishing and printing) 232 employees

SyPE (administration and personnel of the factory) 230 employees

4cp. Texivisin, Gerencia de Recursos Humanos [2005]

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2 FMEA (FAILURE MODE AND EFFECT ANALYSIS)

The FMEA (Failure mode and Effect Analysis) is a systematic method to analyse and rank the

risks of the failures and to prevent them before the customer reaches the product.

The aim of the FMEA is to detect potential failures during the production planning and product

development and to prevent them by realizing measurements to avoid the defects. Analysingevaluation to identify the failures or defects might operate first by using historical data, similar

data for similar products, warranty data, customer complaints and other appropriate information.

And the second is by working with inferential statistics, mathematical modelling, simulations,

concurrent engineering and reliability engineering to define the failures or defects.5The FMEA isalso used to improve the quality of the existing products and to advance the quality control plans

of developing new products. To improve and prevent failures the priorities of failures have to be

defined by three components:

Severity (SEV) effects of the failure

Occurrence (OCC) frequency of the failure


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Detection (DET) ability to detect the failure before it reaches the customer6

To value the defects a numeric scale from 1 to 10 is used is a ranking table. The number 1 is the

lowest and number 10 the highest risk rate. The failures or defects are valued by the Risk Priority

Number to define the priority of the defects. The RPN is a product of the severity, occurrence

and detection. The number by itself is without any meaning because each FMEA has differentmeanings.

5cp. Stamatis [1995], p. 25

6cp. Stamatis [1995], p. 180

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The failure or defect with the highest RPN has to be addressed first to solve the problem and

reduce the defect. After the RPN is determined, then the risk evaluation of the defect begins byrecommending action for the resolution. The risks are defined by minor, moderate, high and

critical.

AnyFMEA conducted properly and appropriately will provide the practitioner with useful

information that can reduce the risk (work) load in the system, design, process, and service. This

is because it is a logical and progressive potential failure analysis method (technique) that

allows the task to be performed more effectively. FMEA is one of the most important early

preventive actions in system, design, process, or service which will prevent failures and errors

from occurring and reaching the customer.7

The concept of applying an FMEA should compose:

Cause-Effect-Diagrams

Safety certifications

Process / System improvement

Extension of knowledge

Documentation of Experiences

Occurrence of customer satisfactions in relation to the effects of failures

Defining warranty claims8

7Stamatis [1995], p. 25

8cp. DGB-Band 13-11 [2004], p. 9


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A good FMEA

Identifies known and potential failure modes

Identifies the causes and effects of each failure mode

Prioritises the identified failure modes according to the risk priority number (RPN) - theproduct of frequency of occurrence, severity, and detection

Provides for problem follow-up and corrective action9

Figure 1: FMEA Model

Modified after: Dailey [2004], p. 8

Besides FMEA there are other variations like FMECA (Failure Mode and Effects and CriticalAnalysis) in the aerospace industry. The difference to the FMEA is in its terms of failure rates

and identification number in dubiousness.

An other characteristic is the reference of system in relation to application.

9Stamatis [1995], p. 26

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2.1 Background10

The FMEA was developed and released in the United States Military Procedure MIL-std-1629 in

November 1949 with the title: Procedures for Performing a Failure Mode, Effects and Critically

Analysis to verify the failures within the production system. In the 1960s the FMEA was added
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from the NASA (American Space Effort) and part of the Apollo program. The concept of

Quality is a very important tool together with Security in the area of aerospace, according tothe safety and reliability of FMEA.

The extension of FMEA was created by the automobile industry, Company Ford in the 80s: Ford

Motor Industry began to apply FMEA in the engineering production with the aim to improve thesafety, quality and reliability of the products.

The Risk priority number (RPN) was developed because of the customers evaluations offailures, to give evidence about the strength and heaviness of the effects of the failures. It also

should define which measures should be done urgently to advance or prevent the failures. Theresult of these calculations was the FMEA form, which accrued in 1986.

By 1988 FMEA was applied in almost all big Automotive Companies. In the Same year ISO9000 (International Organization for Standardization) of business management standards

developed. The ISO was in charge that the organizations developed a significant Quality

Management System in order to improve the Quality and satisfy the Customer needs andexpectations. The QS 9000 can be compared with the ISO 9000 and is special for the automotive

industry. It was developed by Daimler-Chrysler, Ford Company and the general Motors

Cooperation developed QS 9000 in order to standardize the quality

10cp. http://www.theleanmachine.com/newsletters/December2003/FMEA.htm

cp. Mller / Tietjen [2003]

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systems. The FMEA was used for advance quality control plans within the automotive industry.

In February 1993 the Automotive Industry Action Group (AIAG) and the American Society forQuality Control (ASQC) copyrighted the FMEA standards for the whole industry. The standards

are approved and supported by the automotive industry: Ford, Daimler-Chrysler and general

Motors Cooperation and presented in an FMEA Manual to provide general guidelines for

preparing an FMEA.

Today the FMEA is used in plenty of areas in the industry and has become and important tool in

the product and process industry. Since 1996 there is a difference between System-FMEA of the

product and of the process. A new FMEA form was presented in 1996.

2.2 Types of FMEA11

The FMEA is divided into four different types of FMEA, depending on the time of inspection,inspection complexity and the inspection type: System-FMEA, Design-FMEA, Process-FMEA,

Service-FMEA. The procedure is basically in all types similar.


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1. System FMEA

11cp. Stamatis [1995], p. 46

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2. Design FMEA

3. Process FMEA

4. Service FMEA
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For the knitting department the Process FMEA is the most important function because it analyses

the potential failures and defects caused during the manufacturing process.

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2.3 Fundamental ideas of FMEA - why conduct FMEA

The purpose of FMEA is to find the weak points in the production process and analyse theseverity and evaluate the effects besides finding solutions and measurements to prevent the

failures. The FMEA system is also able to improve the product or the process.

There are also other benefits of conducting FMEA:12

Improves the quality, reliability and safety of the products

Increases customer satisfaction

Reduces product development time and costs

Establishes a priority for design improvement actions

Helps in the analysis of new manufacturing and/or assembly process

Lists potential failures and identifies the relative amount of their effects

Develops early criteria for manufacturing, process, assembly, and service

Brings focus to product / process failure modes and their effect on reliability, producibility and

the customer

Provides a record of preventative action in design and/or process improvement

Provides a list of critical and significant characteristics for production and quality planning

Provides historical record for future product failure investigations
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Provides criteria on based prioritisation for design or process improvement

Provides new ideas for future improvements in similar designs or processes

12cp. Stamatis [1995], p. xxvi Dailey [2004], p. 6

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The most important rationale for conducting FMEA is to protect the consumer and producer.

Figure 2: Fundamental ideas of FMEA

Modified after: Meier [2005], p.6 URL: http://www.fmeainfocentre.com/download/kunz_meier.pdf

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2.4 Process FMEA

The process FMEA is a method to identify potential failures during the manufacturing processand provide corrective actions before the first production process starts. To avoid these failures it

is necessary to find out the causes of the problems and present actions to correct the system

before starting the first production. The first production run is always the most important onebecause it conducts samples for the customers and it is not an occasional prototype production.

The change of designs is usually not the major event of this procedure. For each failure in the

system there has to be a specific methodology to prevent the problems or risks, which can arise.
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There are a variety of reasons to focus in identifying and analysing the problems such as

customer requests, conditional improvement philosophy and competition.

The process FMEA is accomplished through the whole production process, including all series of

steps, the product has to follow: labour, machine, method, material, measurement and

environment

considerations. Each of these steps has its own area of creating failures. To conduct a process

FMEA the most important elements are: human, materials, equipment, methods, environment

that can be shown in a Cause-Effect-Diagram to analyse the defects.

Thegoal, purpose, and/or objective of the process FMEA is to define, demonstrate, andmaximize engineering solutions in response to quality, reliability, maintainability, cost, and

productivity as defined by the design FMEA and the customer.13

13Stamatis [1995], p. 157

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The aims of process FMEA are:14

Optimal process reliability

Detection of keeping conditions

Advancement of costing

Environment protection/pollution control

Work safety

The process FMEA must base its requirements on solid needs, wants and expectations of thecustomer.

Before starting to conduct a process FMEA, it is important to do a brainstorming within the team

to analyse the advantages of the FMEA. The main reason for performing a FMEA in the knitting

department is to improve the quality of the fabric and to prevent and decrease the defects and

failures during the manufacturing process. The following chart shows a brainstorming for the

advantages of the FMEA.


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Figure 3: Brainstorming

Modified after: Stamatis [1995], p. xxvii

14cp. DGQ-Band13-11 [2004], p. 44
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acknowledgement i

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