KR100419296B1 - A Method and Program for Analyzing Failure Modes - Google Patents

Abstract

PURPOSE: A method for analyzing a failure mode and a recording medium thereof are provided to prevent omission generated from a failure mode prediction, and define a cause and an effect mechanism of the failure mode systematically and effectively. CONSTITUTION: A central failure mode, which is an analysis target, is listed(S1). A cause mechanism of the central failure mode and related component item are selected/listed(S2). A cause system tree is written by considering a combination relation between a path to the central failure mode and each listed item(S3). A failure form is classified/listed according to generation of the central failure mode(S4). The effect influencing on an upper system is traced by each listed failure state(S5). The cause of the central failure mode is understood by considering the viewpoint for defining the cause mechanism in an order from a factor due to a lower single part of the cause system tree to the factor due to the combination of upper parts.

Description

Analysis method and recording medium of failure mode {A Method and Program for Analyzing Failure Modes}

The present invention relates to a method performed in order to ensure the quality and reliability of the target product in the development stage of the product (system), in particular to prevent omission occurring in the failure mode prediction and to identify the cause and effect mechanism of the predicted failure mode By providing a method to effectively identify, improve the completeness of the developed product, and also systematically accumulate and manage the analysis results, so that knowledge such as personal experience and know-how related to the failure of the target product can be recycled as the knowledge of the organization It relates to a method of analyzing a mode.

The prior art has mainly been a method of estimating the cause of the occurrence of defects or failures. However, known examples of the method for estimating the cause of the defect in the defect phenomenon occurring at the manufacturing stage are Japanese Patent Laid-Open Publication No. Hei 1-167631 and Japanese Patent Laid-Open Publication No. Hei 6-196900. These are to accumulate the conventional defect performance and the data of the cause and to obtain the correlation between the defect pattern and the cause of the defect, and to estimate the cause of the defect accordingly. Further, examples of using the same method for diagnosing a failure include Japanese Patent Laid-Open Publication No. 7-13617 and Japanese Patent Laid-Open Publication No. 7-271587.

In the above known examples, when a defect phenomenon or a failure phenomenon occurs, it is a technique for quickly and accurately executing the repair or repair thereof according to the contents of the phenomenon actually occurring, and it is a technique of estimating a direct cause according to the past idea. Since these methods need to understand most of the failures that can actually occur, it is impossible to accurately estimate the poor properties that result in a large number of manufacturing defects due to a missing review and the characteristics of the product. On the other hand, Japanese Patent Laid-Open No. 1998-80843 proposes a method for estimating poor assembly potential. However, this is not only the top and bottom relationship of the various components is unclear, it is difficult to clearly determine the contents of the third party that does not participate in the analysis.

In general, failure modes and effect analysis (FMEA) and fault tree analysis (FTA) are widely used as methods for predicting and analyzing failure modes. In the 1950s, NASA enacted the Apollo Plan for the launch of the Dalocket in the 1950s, and used the knowledge and knowledge of the analysts in the format of worksheets formulated with the world's best known methods for reliability and safety assessments. The prediction and the analysis are performed by doing. In addition, the FTA is a method initiated by NASA, and analyzes the fault defects of the system by drawing the FT diagram by the analyst's own judgment by using the mapping symbols and the logic symbols.

In case of FMEA, it is easy to analyze the single failure mode occurring in the component of the product to be analyzed, but it is difficult to interpret the failure mode of the complex factors caused by the combination of components or several components. In addition, the FTA is used as a post-analysis method to analyze the cause of the problem after the occurrence of the problem, rather than as a pre-analysis method that interprets the possibility of the problem by predictive thinking.

Since both the FMEA and the FTA are interpreted by the analyst's own judgment, there are many differences in the quality of the results depending on the perspective of the analyst's thinking. By enumerating, not only the causal relationship between the various elements included in the mechanism is unclear, but also the third party who does not participate in the interpretation has considerable difficulty in clearly determining its contents.

In view of the problems with the conventional methodology as described above, the present invention provides a method for preventing the omission from failure mode prediction and systematically and effectively identifying the cause and effect mechanism of the failure mode.

In addition, by implementing the methodology through software, it aims to provide a system that supports efficient interpretation to users and at the same time, D / Bs all information generated in the process and accumulates and recycles it into organizational knowledge.

1 is a block diagram showing the format of a failure mode mechanism of the failure mode analysis method according to the present invention,

2 is a block diagram showing an embodiment of a failure mode mechanism of the failure mode analysis method according to the present invention;

Figure 3 is a flow chart for creating a failure mode mechanism of the failure mode analysis method according to the present invention,

4 is a block diagram showing the system basic configuration and data flow of the failure mode analysis method according to the present invention,

Figure 5 is an embodiment showing the process sequence of the failure mode analysis method according to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: center failure mode 20: influence meter

21: Primary Impact 22: Secondary Impact

30: Cause Cause 31: Primary Cause

32: secondary cause 42: block diagram editing unit

44: failure mode prediction unit 46: failure mode mechanism diagram editing unit

48: worksheet management unit 50: failure mode library

In order to achieve the above object, the present invention provides a method for building a failure mode library in which failure modes are classified and accumulated according to characteristics of a product, a generation part, a occurrence situation, and a predicted viewpoint of a use environment; Completing block diagram editing for creating and editing functional block diagrams, structural block diagrams, functional-structure block diagrams, and process flow diagrams of the product through hierarchical deployment; Extracting information from the block diagram and searching and enumerating fault modes referenceable in the fault mode library to predict fault models; It provides a failure mode analysis method comprising the step of generating a failure mode mechanism for identifying the cause and effect of the predicted failure mode.

In addition, the analysis method of the failure mode of the present invention is characterized in that it comprises a failure mode prediction step of retrieving the failure mode by the user associating the existing similar failure mode and the standard failure mode arranged by perspective .

In addition, in the failure mode analysis method of the present invention, the input, editing and management of data includes a worksheet management unit configured as a worksheet, and the worksheet management unit is inputted to and outputted from the block diagram editing unit, the failure mode library, and the failure mode functional diagram. It is characterized by.

Further, in the failure mode analysis method of the present invention, the preparation of the failure mode mechanism is an enumeration step of the central failure mode to be analyzed; Selecting and enumerating the parts related to the cause of the central failure mode; Creating a cause tree in consideration of the coupling relationship between the path and each part to the central failure mode for the parts listed above; Classifying the failure type according to the occurrence of the central failure mode, identifying the influence on the upper system by the failure type, and the factors caused by the combination of the lower parts and the factors of the upper parts in the cause tree. It is characterized by consisting of the steps of identifying the cause of the central failure mode in consideration of the viewpoint for identifying the cause mechanism.

In addition, the analysis method of the failure mode of the present invention is characterized in that it comprises a statistical analysis step showing the number of failure modes for each failure level in the form of a bar graph, and showing the results of the importance evaluation for the failure mode in the form of a two-dimensional matrix.

In addition, in the present invention, the failure mode library is classified by accumulating the failure mode by the nature of the product, the site of occurrence, the occurrence situation, the predicted viewpoint of the use environment; A block diagram editing unit for creating and editing a functional block diagram, a structural block diagram, a functional-structure block diagram, and a process flow diagram of a product through hierarchical expansion; A failure mode predictor for extracting information from the block diagram and searching for and listing failure modes that can be referred to in the failure mode library; A failure mode mechanism diagram editing unit for grasping the cause and effect of the predicted failure mode; A worksheet management unit for inputting, editing, and managing data into a worksheet and inputting / outputting the block diagram editing unit, the failure mode library, and the failure mode mechanism diagram editing unit; All data of the worksheet, block diagram, and failure mode mechanism are managed on a project basis, and a project management unit for inputting basic information is provided. The recording medium includes a program for analyzing a failure mode.

Hereinafter, the failure mode analysis method and recording medium of the present invention will be described with reference to the drawings.

In the present invention, three concepts such as "layer", "association", and "failure mechanism" are introduced to prevent the omission occurring in the failure mode prediction and to effectively predict the required failure mode. An overview of each concept is as follows.

First, the overview of the "layer" is explained by decomposing the analysis object hierarchically, and then predicting the failure mode for each layer. The failure mode is predicted for the configuration items of the higher level, and then lowered to the lower level step by step. For example, the failure mode is predicted for a component item (part) having the lowest level. The background to the introduction of this concept is that in case of parts, the failure mode generated by the part-to-part or the overall characteristics of a few parts is unpredictable in the prediction of failure modes for component-level components. This is due to the fact that the target of the configuration item should be predicted.

The second overview of "association" outlines several aspects of prediction and prepares examples of failure modes when viewed from that perspective, with failure modes organized by perspective on the subject. The failure mode is predicted by considering and applying the example of. This concept is similar to a person's easy reminder of a friend's name, for example, by providing a perspective (or word) that reminds him of the old friend's name. In practice, the failure mode is implemented by preparing and utilizing a failure mode library in which the failure modes are organized by various points of view. An example of the classification perspective extracted with respect to the failure mode is as follows. First, it is classified into three aspects of the nature of the failure, the occurrence of the failure, and the occurrence of the failure. That is, the nature of the failure is divided into mechanical failure mode, electrical failure mode, chemical failure mode, the occurrence of the failure is divided into failure mode of the object itself, failure mode between the object and the object, the occurrence situation of the failure is the initial failure failure mode It is divided into normal deterioration failure mode and sudden abnormal stress failure mode. For example, when predicting a failure mode by using a failure mode library for a valve, the angle of opening in terms of fixation, chemical appearance, and initial failure in the occurrence of failure ( Failure modes such as dimensions, defects, wear in terms of normal degradation, deformation in terms of sudden abnormal stresses, and the like. In addition, when using the viewpoint of the use environment, it is possible to utilize the failure mode library accumulated for each type of stress depending on the kind of contents flowing inside the valve, that is, oil, gas, water, air, etc. Anticipate possible failure modes.

Finally, the overview of the failure mechanism will be explained by estimating the failure mode of the lower level configuration item by identifying the cause mechanism of the failure mode of the higher level configuration item. Contains a number of failure modes of lower level configuration items, and these failure modes include failure modes that may not be conceived in failure mode prediction for lower level configuration items.

In addition, the failure mode mechanism diagram, which is a structure and diagram of the failure mechanism, is used to analyze the cause and effect mechanism of the failure mode. The failure mode kinematic diagram is a tree-shaped diagram in which several aspects of an interpreter have been set to identify the cause and effect mechanism of the failure.

Figure 1 is a block diagram showing the format of the failure mode mechanism of the failure mode analysis method according to the present invention, will be described with reference to the drawings.

The failure mode kinematic diagram shows the influence system 20 as the influence mechanism at the upper part and the cause system 30 as the cause of the failure at the lower part, centering on the central failure mode 10 which is the failure mode to be analyzed. It is shown hierarchically.

The influence meter 20 classifies the influence of the failure caused by the failure mode 10 into the occurrence-specific mode and tracks the effect of the mode for each such mode in a chain. In the influence system 20, if the influence of the central failure mode 10 differs according to the degree of occurrence, the influence on the upper level after the classification by the degree of occurrence may be the primary effect (21) and the secondary effect (22). Enumerate into hierarchies of tertiary impact.

The causal system 30 classifies the failure mechanism until reaching the failure mode 10 as a mode for each generation region, and sequentially traces the cause of the mode for each such mode. When there are multiple sites in which the central failure mode 10 occurs in the causal system 30, the causes that cause the central failure mode after classification by the occurrence site are the primary cause 31, the secondary cause 32, and the third. Enumerate into hierarchical groups, such as differences.

Figure 2 is a block diagram showing an embodiment of a failure mode mechanism of the failure mode analysis method according to the present invention.

The failure mode mechanism diagram divides the factors related to a single part and the factors related to the combination of two or more parts in the causal system 120 using branches of a tree.

The causal system 120 divides the left and right sides of the | line into a left side and enumerates factors related to initial defects such as design defects and process problems on the left side, and factors related to stress during use on the right side.

Fig. 3 is a flowchart for creating a failure mode mechanism diagram of the failure mode analysis method according to the present invention, and the creation procedure of the failure mode mechanism diagram will be described with reference to the drawings.

First, the central failure mode 10 to be analyzed is enumerated (S1).

Then, the configuration item (part) related to the cause mechanism of the central failure mode 10 is selected and listed (S2).

Paths leading to the central failure mode 10 for each item listed in the above (S2) and a combination relationship between each item (in the case of a single part, between parts and parts or a combination of several parts) In consideration of this, a cause tree is created (S3).

Next, classification and enumeration by failure type (degree of failure) according to occurrence of the central failure mode 10 are performed (S4).

The effect on the upper system for each of the failure states listed in step S4 is tracked (S5).

Finally, in the tree created in (S3), the cause of the central failure mode is traced in consideration of the above-described viewpoint for identifying the cause mechanism in the order of the factors caused by the lower single part and the factors caused by the combination of the upper parts. Identify the mechanism.

Among the factors of the causal system, factors determined to be modes (states) are described in a rectangle, and factors such as stress causing the modes described in a rectangle are described in an ellipse.

The above information is applied to the FMEA method which is widely used for the prediction and analysis of the failure mode, and implemented in software for the efficiency of the work and the D / B of the result.

Figure 4 is a block diagram showing the system basic configuration and data flow of the failure mode analysis method according to the present invention.

Referring to the drawings, the system of the failure mode analysis method according to the present invention includes a worksheet management unit 48, a block diagram editing unit 42, a failure mode mechanism diagram editing unit 46, a failure mode prediction unit 44 and a failure The mode library 50 is configured. In addition, a project management unit (not shown) is formed to manage block diagrams, worksheets, and failure mode mechanisms on a project basis. The project management unit has a function of inputting basic information such as project ID, project name, setting failure mode analysis type and team members such as design, process, and equipment, and managing the user to set worksheet form. Managed as a project.

The worksheet management unit 48 is a function of creating, editing, and managing a worksheet after generating the worksheet template generating unit 41 and is used as a database for outputting results such as statistical analysis. In addition, the worksheet management unit is connected to the modules such as the failure mode prediction unit, the block diagram editing unit, and the recommendation manager so that the work is performed in the worksheet management unit according to the needs of each module. 60).

The block diagram editing unit 42 has a function of creating, editing, and managing various block diagrams and process flow diagrams. Types of block diagrams are structural block diagrams, functional block diagrams, and structural-functional block diagrams. First, a structural block diagram is a block diagram in which a hierarchical structure of components of each product or assembly is divided into component components at the lowest level. It is urbanized. In addition, the functional block diagram shows the hierarchical structure information of the function, and the functional-structure block diagram reads the hierarchical structure information of the functional block diagram to automatically create the structure, and then selectively inserts the components on the structural block diagram to finalize it. You are done. In addition, the process diagram can be produced and edited in the block diagram editing unit, which shows the order for each process. 5 is an example showing the sequence of the process, assuming that the assembly process of the assembly (A) is composed of the process 1 (200) and the process 2 (300), step 1 is the assembly operation 210 and parts of the component a In order to assemble the component a, and to assemble the component a, the operation of placing the component a on a predetermined position of the frame 211 and the operation of pressing the component a 212, and also to assemble the component b For this purpose, a process flow chart consisting of a positioning operation 221 and a screwing operation 222 that put b on a is prepared. That is, the actions required for each process are created and edited according to the flow. The block diagram editor 42 is associated with the modules of the failure mode predictor 44 and the failure mode mechanism editor 46.

The failure mode mechanism diagram editing unit 46 is a function for creating, editing, and managing a failure mode structure diagram. As described above, the central failure mode, the influence of the failure, the cause of the failure modes and factors, parts, and connection line objects are generated. It is integrated into the FMEA workspace 60, which is a user workspace. In addition, the failure mode mechanism editor may have a function of expanding and editing as needed, a function of generating a grid, and a function of turning a snap on and off. In connection with other modules, it is possible to enumerate related parts with information from the created block diagrams, and to search for the failure modes that can be referred to in the failure mode library and bring them to the failure mode and the factor object corresponding to the cause.

The failure mode predicting unit 44 is a function for predicting and managing a failure mode. The failure mode prediction unit 44 may search for a failure mode and a standard failure mode of a similar item previously predicted and predict a new failure mode. The failure mode search of similar items finds the similar failure mode from the existing project by searching the item name or function as a search term, and the standard failure accumulated in the failure mode library by arranging by the viewpoint for prediction when searching and referring to the standard failure mode. Mode allows the predictor to recall the failure mode required by the association.

The failure mode library 50 is a function for constructing and managing a failure mode library, and can classify failure modes into perspectives (failures, occurrences, occurrences, and use environments) to produce a user-specific failure mode library. . The registration and revision of the standard failure mode defines a new point of view so that the failure modes can be newly classified and registered or revised. In connection with other modules, a function for searching and extracting the standard failure mode is built in the failure mode prediction unit 14, and is linked with the failure mode mechanism diagram editing unit 46 and the worksheet management unit 48.

On the other hand, the recommendation management unit 43 has a function of managing the recommendation and is organically associated with the worksheet management unit 48. The recommendation management unit 43 has a function of searching and inquiring recommendations and related information contained in all worksheets of the project by inputting search conditions, etc., and can input and edit the contents of the action and the completion date of the action. . Statistical analysis unit 47 is a function that can check the results of the importance evaluation (including re-evaluation) in the form of a graph (bar graph, 2D Matrix). The bar graph shows the number of failure modes by failure class and shows the number of failure modes by failure class in the form of a bar graph. In addition, according to the search conditions, the results of the importance evaluation for each failure mode can be output in the form of a two-dimensional matrix.

In this system, three concepts, namely, "layer", "association", and "failure mechanism" concept, to prevent the omission occurring in the failure mode prediction and support the effective prediction of the required failure mode are implemented. This includes the following features:

By using the block diagram editor 42, it is designed to perform FMEA for each layer by defining the hierarchical structure by the hierarchical expansion and leveling function of the analysis target, and thus predicts the failure mode for various levels of configuration items. Can enumerate.

In addition, a failure mode library 50 function is included to accumulate / manage failure modes according to various prediction points, so that the operator can predict failure modes and the accumulated failures of the failure mode library 50 in the failure mode prediction 44 window. The modes can be used to easily predict / enumerate the required failure mode.

The failure mode mechanism diagram editing unit 46 is provided to analyze the failure mechanism through the structure and schematic of the failure mechanism. Therefore, the failure mode mechanism diagram for the failure mode of the higher level configuration item is utilized to generate the failure mode mechanism. The failure mode can be extracted.

In addition, the failure mode mechanism diagram editing unit 46 of the present system is a tool for creating a failure mode mechanism diagram as described above, and a failure mode mechanism diagram is generated during the influence and cause analysis process of the failure mode. Can be interpreted systematically and precisely.

In existing FMEAs, it is common to work at the level that lists the effects and causes on the worksheet in the relevant columns for the analysis of the effects and causes of the listed failure modes, which leads to an in-depth analysis of the failure mechanism. This unenumerated content also contained very insufficient information to understand the mechanism. In the case of failure mode effect analysis, there may be various phenomena in the process of reaching the final effect depending on the degree of failure, and the unit sharing the other parts, the target parts, as well as the effect on the upper system of the item, It is necessary to examine the effect on units inputted in parallel to the host system. In case of failure mode cause analysis, there are many factors such as failure mode, stress, condition variation, human error, etc. that cause the failure mode to be analyzed. An in-depth examination of the causal relationship between the elements and each element is necessary. The failure mode mechanism editor 46 assists FMEA workers to perform this review systematically and effectively.

The failure mode mechanism diagram editing unit 46 not only assists the user in creating a failure mode mechanism diagram but also provides attribute information such as all the elements described in the mechanism diagram and the causal relationship between each element as well as the creation of the failure mode mechanism diagram. It is designed to be stored in the D / B 70. Therefore, through the linked worksheet management unit 48, the failure mechanism information expressed in the instrument diagram can be easily arranged on the worksheet, and the information can be usefully used through the search function of the failure mode prediction window in the failure mode prediction. do.

As described above, the present invention is a method for effectively performing prediction and analysis of a failure mode performed on design contents in order to secure quality and reliability of a developed product during a new product development process. In qualitative prediction and interpretation, the result depends not only on the intellectual level of the experience and know-how of the practitioner, but also on the approach of the problem. The present invention has the advantage of improving the prediction and analysis ability while minimizing the deviation according to the practitioner's approach by systematically predicting and analyzing the failure mode, thereby obtaining a better analysis result. In addition, the support software enables more efficient prediction and interpretation, and all information derived during the process is managed through D / B, so that the knowledge of the failure of the analysis object, which has been contained in the individual's head, especially structured It has the advantage of systematically accumulating and recycling knowledge about failure mechanisms that was difficult to organize by expression into organizational assets.

In the detailed description of the present invention as described above, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

Claims (6)

A failure mode library building step of accumulating failure modes by classifying the product properties, occurrence sites, occurrence conditions, and predictive viewpoints of the use environment; A block diagram editing completion step of creating and editing a functional block diagram, a structural block diagram, a functional-structure block diagram, and a process flow diagram of a product through hierarchical development; A failure mode prediction step of retrieving information from the block diagram and a flowchart and searching for and listing a failure mode referenceable in the failure mode library; A failure mode mechanism generation step of identifying the cause and effect of the failure by using the failure mode predicted from the failure mode prediction step as a central failure mode; The failure mode predicting step may further include an associating step in which a user associates the failure mode with the standard failure mode by searching for an existing similar failure mode and arranged by perspective. delete The method according to claim 1, The input, editing and management of data includes a worksheet management unit configured as a worksheet, wherein the worksheet management unit is inputted to and outputted from the block diagram editing unit, the failure mode library, and the failure mode mechanism. The method according to claim 1, The preparation of the failure mode mechanism is an enumeration step of the central failure mode to be analyzed; Selecting and enumerating the parts related to the cause of the central failure mode; Creating a cause tree in consideration of the combination of the path and each component to the central failure mode for the components listed above; Classifying a failure type according to occurrence of the central failure mode; Identifying an effect on a higher system for each failure type; Analysis of the failure mode comprising the steps of identifying the cause of the central failure mode in consideration of the viewpoint for identifying the cause mechanism in the order of the factors due to the lower single component to the combination of the upper components in the cause tree Way. The method according to claim 1, The failure mode analysis method includes a statistical analysis step of displaying the number of failure modes for each failure class in the form of a bar graph and showing a result of the importance evaluation for the failure modes in a two-dimensional matrix form. . Failure mode library that accumulates failure modes by classifying them into product properties, occurrence areas, occurrence conditions, and predictive viewpoints of usage environment; A block diagram editing unit for creating and editing a functional block diagram, a structural block diagram, a functional-structure block diagram, and a process flow diagram of a product through hierarchical expansion; A failure mode prediction unit for retrieving information from the block diagram and a flowchart and searching for and listing failure modes that can be referred to in the failure mode library; A failure mode mechanism diagram editing unit for identifying the cause and effect of the failure by using the predicted failure mode as a central failure mode; A worksheet management unit for inputting, editing, and managing data in a worksheet and inputting / outputting the block diagram editing unit, the failure mode library, the failure mode prediction unit, and the failure mode instrument diagram editing unit; And a project management unit configured to manage all data of the worksheet, block diagram, and failure mode mechanism in a project unit, and input basic information. The recording medium comprising a program for analyzing a failure mode.