This diploma thesis “APPLYING FMEA IN THE KNITTING PROCESS” shows how to develop a FMEA in the production process of the knitting department. The quality control shows several important defects, which have to be improved and reduced.
The FMEA (Failure Mode and Effect Analysis) is an analysis to detect and prevent potential failures and defects in the quality assurance.
While getting familiar with the production procedure of knitting fabric the idea to develop a FMEA became more interesting. In the textile industry the used methods for predicting quality assurance are still not very common. The knitting department is still using a classic strategy of analysing and preventing defects.
First there was the need to define a responsible team to develop a FMEA process. The team members are selected from different areas in the production. To learn about the purposes and benefits of an FMEA the chief of the team should visit a training-program for moderators.
The process FMEA includes 13 steps to follow and conduct a FMEA. Process FMEA, because it focuses on the failure modes caused by process or assembly deficiencies.
The most important reason for conducting a FMEA is to improve its process and quality.
The first step in developing a FMEA is to define the complete production process of knitting. Therefore it is necessary to identify the detailed functions of the workstations. Further the most important and critical defects have to be defined with its causes and defects. The Cause-Effect-Diagram is a helpful method to analyse the root causes. The defects are listed by its appearance according to the functions in the process. It is important to do an analysis of the total percentages of defects before starting to apply the FMEA process in the procedure.
Risk evaluation is in charge of evaluating the defects according to severity, occurrence and detection. The ranking system is between 10 and 1, in which 10 identifies a very high risk and 1 a minor risk. Severity applies to the importance of the defect, occurrence to the frequency, and detection to the efficiency of detecting the defect.
At last the Risk Priority Number (RPN) is calculated by multiplying severity by occurrence and by detection to define the total potential failure or defect. Recommended actions are to be defined in order to give solution and reduce the problems in the procedure.
Table of Contents
1 INTRODUCTION
1.1 Diploma Thesis
1.2 The Company
2 FMEA (FAILURE MODE AND EFFECT ANALYSIS)
2.1 Background
2.2 Types of FMEA
2.3 Fundamental ideas of FMEA – why conduct FMEA
2.4 Process FMEA
3 PERFORMING A PROCESS FMEA
3.1 Defining a TEAM
3.2 Bill of materials (BOM)
3.3 Organization in the productive area
3.3.1 Production process of the knitting department
3.3.2 Workstation functions within the process
3.4 Defect overview
3.5 Cause-Effect-Diagrams
3.6 Detected defects January-August 2005
3.7 Detected defects in the working process
3.8 Risk evaluation
3.8.1 Severity (SEV)
3.8.2 Occurrence (OCC)
3.8.3 Detection (DET)
3.8.4 Risk Priority Number (RPN)
3.9 Arrangements and solutions
3.10 Checking the process – action taken to reduce the defects
3.10.1 Which checkups are already planned?
3.10.2 RPN new calculation
3.11 FMEA form
4 CONCLUSION
5 REFERENCES
6 APPENDIX
6.1 Handbook FMEA
6.2 Complete FMEA form
Project Goals and Themes
The objective of this thesis is to implement a systematic Failure Mode and Effect Analysis (FMEA) within the knitting department to enhance production quality and reduce defects. The study explores the integration of risk assessment techniques into the daily manufacturing flow to shift from reactive defect detection to proactive error prevention.
- Development of a process-specific FMEA framework for textile production.
- Identification and systematic analysis of common knitting defects.
- Risk prioritization using the Risk Priority Number (RPN) methodology.
- Establishment of corrective actions and mistake-proofing (Poka Yoke) procedures.
- Performance evaluation through comparative analysis of pre- and post-implementation quality data.
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3.1 Defining a TEAM
To perform a process FMEA, a responsible team has to be selected. This team should have between 3 and 6 members, which should always be present during all the meetings and have certain responsibilities. These members are the “core-team”. The “support-team” is formed by employees with specialised knowledge who might sometimes be present. The support Team is helpful for creating questions in relation to the production process (fabric, machines). Both teams are also connected to the organisation, to suppliers and to the customers of the firm. They have a collective knowledge and all decisions have to be made by these groups.
The FMEA team comprise:
• Chief of the project
• Production manager
• Quality control manager
• Persons with specialised knowledge (knitter, mechanic, production supervisor)
Summary of Chapters
1 INTRODUCTION: Discusses the importance of quality assurance in the textile industry and introduces FMEA as a strategic tool for defect prevention.
2 FMEA (FAILURE MODE AND EFFECT ANALYSIS): Explains the theoretical foundations, the evolution of FMEA from military/aerospace to automotive, and the core risk assessment components (Severity, Occurrence, Detection).
3 PERFORMING A PROCESS FMEA: Details the practical 13-step methodology for executing a process FMEA in a knitting production environment, including team selection and risk evaluation.
4 CONCLUSION: Summarizes the findings, confirming that applying FMEA improves quality standards and helps reduce manufacturing defects significantly.
5 REFERENCES: Lists the scholarly literature and technical resources used for the analysis.
6 APPENDIX: Contains supplementary materials, specifically the FMEA handbook and the standardized FMEA forms used in the practical application.
Keywords
FMEA, Knitting Process, Quality Assurance, Risk Priority Number, Defect Prevention, Textile Industry, Process Improvement, Poka Yoke, Severity, Occurrence, Detection, Manufacturing Quality, Risk Management, Production Efficiency, Cause-Effect-Diagram.
Frequently Asked Questions
What is the primary purpose of this research?
The thesis aims to improve production quality in a knitting department by implementing a systematic FMEA (Failure Mode and Effect Analysis) to detect and prevent potential manufacturing failures.
Which methodology is used to assess risks in this study?
The study utilizes the RPN (Risk Priority Number) system, calculated by multiplying the scores for Severity, Occurrence, and Detection, to rank and address critical manufacturing defects.
What are the central themes of the document?
The work focuses on process FMEA, defect identification in knitting machines, team-based quality management, and the use of Cause-Effect (Ishikawa) diagrams to find root causes of problems.
How is the knitting process analyzed?
The process is deconstructed into specific workstations, and the responsibilities of various roles—from knitters to process engineers—are documented to identify where and how defects occur.
What results were achieved through this FMEA?
By implementing corrective actions based on the FMEA, the total number of defects was reduced by approximately 82.3% between August and December 2005.
How is the FMEA team structured?
The team consists of a core group of 3 to 6 members, including the project chief, production manager, and quality control manager, supported by specialists like mechanics and knitters.
Why are Cause-Effect-Diagrams essential to this process?
These diagrams are used to visualize the root causes of specific defects like "Barré" or "Pinholes," categorizing them by human, machine, method, material, and environment factors.
What is the "Poka Yoke" concept mentioned?
It refers to mistake-proofing methods used to design production steps that are inherently resistant to error, thereby preventing defects at their source.
- Quote paper
- Inkeri Walser (Author), 2006, Applying FMEA in the knitting process, Munich, GRIN Verlag, https://www.grin.com/document/74302
