Fault root cause tracing of complicated equipment based on fault graph

2012 ◽  
Vol 227 (1) ◽  
pp. 17-32 ◽  
Author(s):  
Xinlin Huang ◽  
Jianmin Gao ◽  
Hongquan Jiang ◽  
Zhiyong Gao ◽  
Fumin Chen
Keyword(s):  
Failure Modes ◽  
Complex Structure ◽  
Special Kind ◽  
Multiple Root ◽  
Propagation Mode ◽  
Mathematical Tool ◽  
Fault Propagation ◽  
Root Cause ◽  
Graph Reachability

Fault root causes tracing of complicated equipment in modern process industry is very important for accident and economic loss prevention. Due to the structure complexity of complicated equipment, failures happen from small parts and propagate through complex pathways often leading to serious system faults. These kind of faults caused by non-critical parts account for a large part of all the faults of complicated equipment and often cannot get enough attention in fault diagnosis. In order to trace the root causes of this kind of fault, the failure dependent relationship and fault propagation mode must be modeled accurately and effectively. Fault graph proposed by H. P. Alesso is a useful tool to represent complex structure and fault propagation pathway of complicated equipment with a special kind of fault-oriented directed graph expanded from fault tree. Fault graph takes advantage of graph rather than tree to describe complex relation between failure modes of components, and uses logic connectives to connect failure modes with logical relationship. Based on the basic concept of fault graph introduced by H. P. Alesso, this article focuses on the issues of fault graph constructing and fault graph fault root causes deducing. A fault graph constructing method was firstly discussed which uses the results of failure mode and effects analysis and the mathematical tool of polychromatic matrix and can be easily performed with the least manual work. Then the fault root causes deducing method of fault graph was investigated which focuses on fault graph reachability calculation and fault propagation pathway searching. The fault graph reachability calculation is put forward from doubletons to multiple root causes so that the reachabiltiy of any steps of fault graph pathway can be calculated. The fault propagation pathway searching method can be performed to reveal the detailed fault propagation pathway. A case study of fault graph modeling and fault root causes analysis based on fault graph of a certain type of centrifugal compressor which has complex internal structure is introduced. The case study shows that the proposed method is effective for fault root cause tracing of complicated equipment.

Case Study and Fault Modeling for Wrong Redundancy Evaluation on DRAM Devices

2007 ◽  
Author(s):  
Martin Versen ◽  
Dorina Diaconescu ◽  
Jerome Touzel
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Fault Modeling ◽  
Mode Analysis ◽  
Root Cause ◽  
Failure Mode Analysis

Abstract The characterization of failure modes of DRAM is often straight forward if array related hard failures with specific addresses for localization are concerned. The paper presents a case study of a bitline oriented failure mode connected to a redundancy evaluation in the DRAM periphery. The failure mode analysis and fault modeling focus both on the root-cause and on the test aspects of the problem.

Applying Advanced FMEA Methods to Vehicle Fire Cause Determinations

2011 ◽  
Author(s):  
Kerry D. Parrott ◽  
Pat J. Mattes ◽  
Douglas R. Stahl
Keyword(s):  
Automotive Industry ◽  
Failure Modes ◽  
Illustrative Case ◽  
Analysis Tool ◽  
Fire Investigation ◽  
Root Cause ◽  
Product And Process ◽  
Illustrative Case Study ◽  
Fire Cause

This paper proposes that the advanced Failure Modes and Effects Analysis (FMEA) techniques and methodology currently used by the automotive industry for product and process design can be reversed and used as an effective failure/root cause analysis tool. This paper will review FMEA methodologies, explain the newest advanced FMEA methodologies that are now being used in the automotive industry, and will then explain how this methodology can be effectively reversed and used as a failure analysis and fire cause determination tool referred to as a “reverse FMEA” (rFMEA). This paper will address the application of these techniques and methodology to vehicle fire cause determination. This methodology is particularly suited to situations where multiple potential fire causes are contained within an established area of origin. NFPA 921 Guide for Fire & Explosion Investigations [1] and NFPA 1033 Standard for Professional Qualifications for Fire Investigator [2], often referenced by the fire investigation community, prescribe following a systematic approach utilizing the scientific method for fire origin and cause determinations. The rFMEA methodology is proposed as a fire investigation tool that assists in that process. This “reverse FMEA” methodology will then be applied to a hypothetical, illustrative case study to demonstrate its application.

scholarly journals A Factory Analysis on the Proportion of Defects Reduction in The Animal Feed Pellet Production Process using Design of Experiment Analysis

2019 ◽  
Vol 3 (2) ◽  
pp. 26-33
Author(s):  
Keyword(s):  
Production Process ◽  
Failure Modes ◽  
Animal Feed ◽  
Fractional Factorial ◽  
Pareto Chart ◽  
Manufacturing Defects ◽  
Root Cause ◽  
Pellet Production ◽  
Feed Pellet

The aim of this research is to reduce a number of defects during a feed pellet production process to improve customer satisfaction. A factory case study produces the feed pellets for several species such as food for pigs, chickens, and ducks. Production data from January to June 2017 manufacturing found that the manufacturing defects rate were about 3.32%. The data showed that the overall defects originated from different problems; 1) cracked or broken food; 2) high humidity; 3) distorted of product color; and 4) an ingredient error, respectively. Statistical methods, design analysis, and cause analysis techniques e.g. the Ishikawa diagram, Pareto chart, and FMEA (Failure Mode and Effects Analysis) were applied to help the factory to identify the main root cause of the defects and the potential failure modes of the factory case study. Due to an increasing number of complaints, this study only concentrated on the duck feed pellet production process. The study was divided into two parts: finding the root cause of the defects, which are the most critical factors for further analysis, and applying an experimental statistical design to decrease the number of defects during the duck pellet production process. The problem with cracked or broken pellets (dust) was found as the main factor affecting the production defects. Results showed that the main factors contributing to the amount of dusk in the duck feed productions came from three factors as follow: the thickness of die, distance between compression rollers and die, and time and temperature of mill machine needed during compressing the duck feed pellet production. Both the fractional factorial experimental design, 2k and 3k, were used to evaluate the influence of each factor on the duck feed production defects. The results by using the factorial 2K experimental show that the most important variable in duck pellets production were thickness of the die, distance between compression rollers and die, and temperature of mill machine needed during compressing the duck feed pellet production while time was not an interaction effect in this problem. The 3k factorial design was used to determine the interaction effects for the duck pellets production process. The experiment was ran and tested for 3 months. The final outcomes showed a significant reduction of defects from 2.51% to 1.09% (P<0.01). The results indicated that thickness -20 mm. of the die, 0.05 mm of distance between compression rollers and die, and 95 degree Celsius of temperature of mill machine needed during compressing the duck feed pellet production would be the most appropriate set of pelleting machine for the duck production process case study.

scholarly journals Root Cause Analysis of a Printed Circuit Board (PCB) Failure in a Public Transport Communication System

2022 ◽  
Vol 12 (2) ◽  
pp. 640
Author(s):  
Cher-Ming Tan ◽  
Hsiao-Hi Chen ◽  
Jing-Ping Wu ◽  
Vivek Sangwan ◽  
Kun-Yen Tsai ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Failure Modes ◽  
Essential Element ◽  
Circuit Board ◽  
Cause Analysis ◽  
Printed Circuit ◽  
Root Cause ◽  
Burn Out ◽  
Root Cause Identification

A printed circuit board (PCB) is an essential element for practical circuit applications and its failure can inflict large financial costs and even safety concerns, especially if the PCB failure occurs prematurely and unexpectedly. Understanding the failure modes and even the failure mechanisms of a PCB failure are not sufficient to ensure the same failure will not occur again in subsequent operations with different batches of PCBs. The identification of the root cause is crucial to prevent the reoccurrence of the same failure. In this work, a step-by-step approach from customer returned and inventory reproduced boards to the root cause identification is described for an actual industry case where the failure is a PCB burn-out. The failure mechanism is found to be a conductive anodic filament (CAF) even though the PCB is CAF-resistant. The root cause is due to PCB de-penalization. A reliability verification to assure the effectiveness of the corrective action according to the identified root cause is shown to complete the case study. This work shows that a CAF-resistant PCB does not necessarily guarantee no CAF and PCB processes can render its CAF resistance ineffective.

Root-Cause Investigations of Stitch Bond – Shearing by Means of 3D-X-ray Computer Tomography (XCT), Metallographic Polishing and FIB

2010 ◽  
Author(s):  
Peter Jacob ◽  
Iwan Jerjen ◽  
Giovanni Nicoletti
Keyword(s):  
Failure Modes ◽  
Typical Case ◽  
Bending Properties ◽  
Thermomechanical Stress ◽  
X Ray ◽  
Root Cause ◽  
Electrical Connections ◽  
Non Destructive ◽  
Non Destructive Characterization

Abstract Since new packaging technologies came up, sensitive failure modes, which were difficult to prove, increased. In many cases, an interaction of bending properties, thermomechanical stress and the material compounds used, cause intermittent failures related to electrical connections. Since any decapsulation might falsify analysis results, non-destructive characterization approaches are of utmost importance for future failure analysis. By means of a typical case study, the capabilities and limitations of a highly developed X-ray tool in such application has been outlined as well as the complexity of root cause findings.

Case Study of ESD-induced Pin Leakage Failure Solved Using Novel Powered TIVA Technique

2018 ◽  
Author(s):  
Sneta Mishra ◽  
Daniel R. Bockelman
Keyword(s):  
Root Cause ◽  
Leakage Failure

Abstract A case study is presented of a core CPU product where FA/FI debug is performed for an ESD-related pin leakage issue on an IO family to root cause and qualify the product. A Powered TIVA technique is used to localize the damage to the termination resistor circuitry of the affected IO block when the pin is tristated using a device tester. Failure characterization shows a gate to drain short on the transistor, with nanoprobing confirming a solid short on gate to drain and TEM finding a short at the location indicated by the TIVA hits.

Failure Analysis Case Study of a 1.5 Meter Space Flex Harness

2017 ◽  
Author(s):  
Erick Kim ◽  
Kamjou Mansour ◽  
Gil Garteiz ◽  
Javeck Verdugo ◽  
Ryan Ross ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Failure Modes ◽  
Field Of View ◽  
Area Of Interest ◽  
Air Stream ◽  
Novel Method ◽  
Temperature Controlled ◽  
Non Destructive ◽  
Failure Site

Abstract This paper presents the failure analysis on a 1.5m flex harness for a space flight instrument that exhibited two failure modes: global isolation resistances between all adjacent traces measured tens of milliohm and lower resistance on the order of 1 kiloohm was observed on several pins. It shows a novel method using a temperature controlled air stream while monitoring isolation resistance to identify a general area of interest of a low isolation resistance failure. The paper explains how isolation resistance measurements were taken and details the steps taken in both destructive and non-destructive analyses. In theory, infrared hotspot could have been completed along the length of the flex harness to locate the failure site. However, with a field of view of approximately 5 x 5 cm, this technique would have been time prohibitive.

Temperature and Humidity Dependent Reliability Analysis of RGB LED Chips

2006 ◽  
Author(s):  
Jun-Xian Fu ◽  
Shukri Souri ◽  
James S. Harris
Keyword(s):  
Reliability Analysis ◽  
Printed Circuit Board ◽  
Light Emitting Diode ◽  
Circuit Board ◽  
Light Emitting ◽  
Printed Circuit ◽  
Root Cause ◽  
Micro Cracks ◽  
Temperature And Humidity

Abstract Temperature and humidity dependent reliability analysis was performed based on a case study involving an indicator printed-circuit board with surface-mounted multiple-die red, green and blue light-emitting diode chips. Reported intermittent failures were investigated and the root cause was attributed to a non-optimized reflow process that resulted in micro-cracks and delaminations within the molding resin of the chips.

Methodology for Analysis of Schottky Diode Failures

2010 ◽  
Author(s):  
Bhanu P. Sood ◽  
Michael Pecht ◽  
John Miker ◽  
Tom Wanek
Keyword(s):  
Failure Mode ◽  
Schottky Diode ◽  
Failure Modes ◽  
Schottky Diodes ◽  
Failure Mechanisms ◽  
Forward Voltage ◽  
Fast Switching ◽  
Voltage Drops ◽  
The Common

Abstract Schottky diodes are semiconductor switching devices with low forward voltage drops and very fast switching speeds. This paper provides an overview of the common failure modes in Schottky diodes and corresponding failure mechanisms associated with each failure mode. Results of material level evaluation on diodes and packages as well as manufacturing and assembly processes are analyzed to identify a set of possible failure sites with associated failure modes, mechanisms, and causes. A case study is then presented to illustrate the application of a systematic FMMEA methodology to the analysis of a specific failure in a Schottky diode package.

Microhardness Testing on Via Fill Material for Via In Pad Technology

2003 ◽  
Author(s):  
Norman J. Armendariz ◽  
Carolyn McCormick
Keyword(s):  
Printed Circuit Board ◽  
Failure Modes ◽  
Strong Dependence ◽  
Circuit Board ◽  
Electrical Performance ◽  
Gravimetric Analysis ◽  
Passive Components ◽  
Root Cause ◽  
Fill Material ◽  
Signal Routing

Abstract Via in pad PCB (Printed Circuit board) technology for passive components such as chip capacitors and resistors, provides the potential for improved signal routing density and reduced PCB area. Because of these improvements there is the potential for PCB cost reduction as well as gains in electrical performance through reduced impedance and inductance. However, not long after the implementation, double digit unit failures for solder joint electrical opens due to capacitor “tombstoning” began to occur. Failure modes included via fill material (solder mask) protrusion from the via as well as “out gassing” and related “tombstoning.” This failure analysis involved investigating a strong dependence on PCB supplier and, less obviously, manufacturing site. Other factors evaluated included via fill material, drill size, via fill thermal history and via fill amount or fill percent. The factor most implicated was incomplete cure of the via fill material. Previous thermal gravimetric analysis methods to determine level of polymerization or cure did not provide an ability to measure and demonstrate via fill cure level in small selected areas or its link to the failures. As a result, there was a metrology approach developed to establish this link and root-cause the failures in the field, which was based on microhardness techniques and noncontact via fill measuring metrologies.

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