JP4507586B2 - Failure mode effect analysis system and recording medium - Google Patents

Description

The present invention relates to a failure mode impact analysis system that extracts failure modes and analyzes the impact, and in particular, records a failure mode impact analysis system that is effective in preventing product assembly errors and a program used therefor. The recording medium .

In recent years, overseas expansion of Japanese companies has become very popular. However, it is a fatal wound for companies to lead to a decline in product quality by expanding overseas, and the issue of the manufacturing department to achieve the same quality worldwide is how to maintain and ensure the quality of the designed product in the production process It is. In other words, this is an enhancement of “preventing assembly errors” in the production process.
Conventionally, in order to deal with this assembly error, in addition to the basic training of assembly workers and the training of workers based on work standards, the concept of quality control that “improves the process and prevents defective products”. Has been practiced.
In general, the output of production preparation is to prepare equipment for production, and at the same time create manufacturing quality, but there is no index to measure the quality of this quality creation, and the activity is the recurrence of past defects. The focus has always been on incorporating prevention in the best possible way.

Published by Katsushige Onodera

However, coupled with the expansion of global production, it is difficult to reduce the number of assembly errors.
On the other hand, as a method for extracting an assembly error countermeasure, for example, Non-Patent Document 1 is applied and a failure mode effect analysis system is used as a procedure.
However, even if such a failure mode and effects analysis (FMEA: Failure Mode and Effects Analysis) system is used, its effectiveness has not been improved.
The reason is as follows.
(1) The hit rate for effective measure extraction is low for the time required to create the procedure manual.
(2) Persons who do not have past knowledge / knowledge in the current procedure manual cannot effectively create a procedure manual.
(3) To prevent assembly errors (human error), it is left to worker education, and the idea that it is different from production preparation is the mainstream.
As described above, there is an urgent need to study a new method for studying measures to prevent assembly errors for expanding global production.

Such a technical problem is not limited to a method for extracting countermeasures against assembly errors, but can be widely applied to a failure mode extraction method and its influence analysis method.
The present invention has been made in order to solve the above technical problems, and provides a failure mode effect analysis system capable of easily creating a failure mode effect analysis list without any past experience / knowledge, and to this The present invention provides a recording medium on which a program to be used is recorded .

The inventor analyzed the cause of assembly errors of products such as copiers and printers, and obtained the results shown in FIG. According to the figure, it has been found out that the problems are concentrated in the in-house assembly process and the “prevent assembly error” relationship with the supplier parts in the production preparation process.
In addition, when the contents of assembly errors of products such as copiers and printers were analyzed in both countries A and B, the results shown in FIG. 18 were obtained. According to the figure, it was found that the types of assembly errors and their occurrence frequency ranks are the same.
According to these results, the present inventor arrived at the idea that the assembly errors can be organized, and that there are certain occurrence conditions, and that these can be systematized. We obtained knowledge that it is possible to construct a system that allows an inexperienced engineer to easily assume the occurrence level of assembly errors if the case is used as a database as past knowledge / knowledge.

The basic configuration of the present invention is based on the knowledge as described above, and includes a control processing means 1 that can be controlled by the program medium 2 as shown in FIG. The failure mode impact analysis system for creating a failure mode impact analysis list (FMEA list) 6 corresponding to each work category 5 is selected by the control processing means 1 as a failure mode corresponding to each work category 5 is selected. The failure mode extraction unit 3 that extracts the corresponding work categories 5 and the mode influence analysis unit 4 that analyzes the influence of the failure mode extracted by the failure mode extraction unit 3 are provided .
In particular, the present invention includes a control processing means 1 that can be controlled by the program medium 2, and the control processing means 1 includes the control processing means 1 for analyzing the influence of a failure mode based on a product assembly error in which the number of processed products per period changes. A failure mode / effect analysis system (FMEA list) 6 for creating a failure mode / effect analysis list (FMEA list) 6 corresponding to each work category 5, wherein the control processing means 1 selects a failure mode corresponding to each work category 5 A failure mode extraction unit 3 that extracts corresponding to each work category 5 and a mode influence analysis unit 4 that analyzes the influence of the failure mode extracted by the failure mode extraction unit 3. 4 shows the degree of occurrence according to the level of the occurrence condition leveled for each target failure mode, the degree of outflow set by level indicating at which stage the presence of the target failure mode can be detected, and the target reason An importance calculation unit that integrates and calculates the importance as an impact analysis result for each target failure mode using the influence set for each level of the impact on the user when shipped due to a failure caused by the mode, The measure ranking display unit 9 is provided which can display the measure ranking for the importance and the measure ranking is weighted according to the number of processed products per period. .

In such technical means, the present case broadly includes a system for extracting a failure mode and analyzing the influence of the extracted failure mode. Here, the failure mode may be anything that indicates the content of the failure, and includes, for example, those based on product assembly errors.
Further, this case is based on a system provided with “control processing means 1 that can be controlled by the program medium 2”. Although it may be possible to create the FMEA list 6 manually, it is usually considered that a workstation such as a computer is used. However, this case does not mean that everything is automated, and it is a matter of course that a part of the FMEA list 6 is manually created.
Furthermore, the present invention only needs to create the FMEA list 6 and does not necessarily need to be output on a sheet, and includes what is simply displayed as electronic information.

Further, the control processing means 1 may be functionally provided with a failure mode extraction unit 3 and a mode influence analysis unit 4.
Here, as the mode influence analysis unit 4, any algorithm can be used as long as it analyzes the influence of the failure mode, but as a typical aspect, the mode influence analysis unit 4 is at the occurrence condition level. The level of outflow according to the level, the outflow level set according to the level at which the presence of the failure mode can be detected, and the impact on the user when shipping with the failure caused by the failure mode set according to the level For example, an effect analysis may be performed by integrating these values. As described above, by using “occurrence degree × outflow degree × influence degree”, the influence analysis can be performed more accurately.

In this aspect, the mode effect analysis unit 4 includes the countermeasure rank display unit 9, and by including such a countermeasure rank display unit 9, even if there is no past experience or knowledge, the failure mode influence analysis is performed. It is possible to accurately evaluate the rank of the measure based on the result.
Here, as a preferable aspect of the countermeasure rank display part 9, the aspect weighted according to the number of processed products per period is mentioned. In this way, weighting is performed in consideration of the number of processed products (for example, the number of Nissan units or the number of Nissan inspections), so that the measure rank can be analyzed in more detail according to the number of processed units.

Further, as a preferred aspect of the present invention, as shown in FIG. 1, in addition to the above-described configuration, the failure mode extraction unit 3 further includes a failure category corresponding to the designated work category 5 and a failure in each failure category. Examples include an association display unit 8 that is associated with a mode and can be displayed.
The significance of the failure mode and the basic configuration of the failure mode extraction unit 3 and the mode effect analysis unit 4 are substantially the same as those of the above-described aspect of the invention. The same applies to the following embodiments.
In this aspect, the failure mode extraction unit 3 includes the association display unit 8. If such an association display unit 8 is provided, even if there is no past experience or knowledge, according to the work category 5. The failure mode can be accurately grasped together with the failure classification, and the failure mode can be extracted more accurately.

Furthermore, as another preferable aspect of the present invention, as shown in FIG. 1, in addition to the above-described configuration, the failure mode extraction unit 3 can select generation conditions leveled for each failure mode. The thing provided with the generation condition selection part 7 is mentioned.
In particular, in this aspect, the failure mode extraction unit 3 includes the generation condition selection unit 7 as a characteristic function unit.
Here, the generation condition selection unit 7 has a file in which the generation conditions leveled for each failure mode (for example, assembly error) are stored in advance, and can be selected from this file.
According to this aspect, it is possible to accurately select the occurrence condition for each failure mode without any past experience or knowledge, and the possibility (occurrence degree) of occurrence of the failure mode from the leveling of the occurrence condition Can be determined in detail.

As another preferred embodiment of the present invention, as shown in FIG. 1, in addition to the above-described configuration, the mode effect analysis unit 4 further includes a countermeasure candidate display unit 10 capable of displaying countermeasure candidates. Can be mentioned.
In this mode, the mode effect analysis unit 4 includes the countermeasure candidate display unit 10, and by providing such a countermeasure candidate display unit 10, the countermeasure can be easily and accurately performed without any past experience or knowledge. Can be selected.
In this case, the countermeasure candidate display unit 10 may be appropriately selected. For example, a countermeasure example for each failure mode is extracted in advance, and a countermeasure plan in which countermeasure candidates are stored for each failure mode, for example, is extracted. It is only necessary to display a candidate for each failure mode extracted by creating a file and searching the countermeasure solution file.

Further, as another preferable aspect of the present invention, as shown in FIG. 1, in addition to the above-described configuration, the failure mode extraction unit 3 and the mode effect analysis unit 4 further include a plurality of pieces of necessary information. It is provided with an automatic processing work environment that is displayed by being divided into sheets and interlocked so that they can be associated with each other.
According to this aspect, the FMEA list 6 can be automatically created while adopting an interactive format, and the FMEA list 6 can be easily created accordingly.

The present invention is not limited to the failure mode effect analysis system described above, but also targets a computer-readable recording medium that records a program for causing a computer to function as the failure mode effect analysis system described above .
This takes into account the transaction of the recording medium before being installed in the system.

According to the failure mode effect analysis system according to the present invention, a failure mode extraction unit that extracts a failure mode corresponding to each work category corresponding to each selected work category, and the failure mode extraction unit extracts the failure mode. Since it has a mode impact analysis unit that analyzes the impact of failure modes, it is possible to analyze the impact of failure modes extracted for each selected work category, and to improve the mode impact analysis unit (measurement rank display) In order to analyze the impact of failure modes based on product assembly errors that change the number of products processed per period, the rank of countermeasures is weighted, so even if there is no past experience or knowledge, It is possible to accurately and easily analyze the influence of a failure mode based on a product assembly error in which the number of hits varies.
Furthermore, in the failure mode effect analysis system according to the present invention, the failure mode generation unit can be easily selected by the device of the failure mode extraction unit (occurrence condition selection unit, association display unit), or the failure mode is failed. If the information is displayed in association with the classification, the failure mode can be extracted more accurately even if there is no past experience or knowledge.
In addition, in the failure mode influence analysis system according to the present invention, if the countermeasure candidate is displayed in advance by the device of the mode influence analysis part (measure candidate display part), even if there is no past experience or knowledge, Further, the failure mode influence analysis can be performed accurately and easily.
Furthermore, in the failure mode effect analysis system according to the present invention, if a work environment that can be automatically processed is given to the failure mode extraction unit and the mode effect analysis unit, the failure mode extraction and failure mode effect analysis are automatically performed. The failure mode effect analysis list (FMEA list) can be efficiently created.
Also, according to the recording medium of the present invention, the above-described failure mode effect analysis system can be easily constructed simply by installing in the system.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
Embodiment 1
2 and 3 show Embodiment 1 of a failure mode / effect analysis system (hereinafter referred to as FMEA system as required) to which the present invention is applied.
In the figure, an FMEA system 20 is applied to a system for preventing assembly errors of products such as copying machines and printers. A program medium (not shown) for preventing assembly errors is stored in the memory of a personal computer. By installing and executing this program medium, an FMEA list 30 for preventing a series of assembly errors is obtained.

Here, a configuration example of the FMEA system 20 will be described.
In the FMEA system 20, reference numeral 21 denotes an element number. The work list 21 may be created on the spot by selecting “Create work list” after opening the worksheet, or may be created on the spot. It may be created by manual input or transcription using the product production preparation material 31 in which is written.
Reference numeral 22 denotes a failure mode / occurrence condition level file for each work activity, which is based on the past assembly error case analysis data 32 and is filed when the initial worksheet is created. .
Further, reference numeral 23 is an outflow degree evaluation table showing the degree (outflow degree) at which stage the presence of a failure can be detected in the current confirmation system, and the point becomes higher as the later of the process.
Furthermore, reference numeral 24 is an influence degree evaluation table showing the degree (influence degree) of problems given to users (including OEM customers) when shipped with the failure.
Reference numeral 25 is a countermeasure rank table showing the certainty of countermeasures (measure rank) based on the accumulated points (importance) of “occurrence degree” (details will be described later), “outflow degree”, and “impact degree”.

And this FMEA system 20 advances a process according to the processing flow shown in FIG. 4, and produces the FMEA list | wrist 30. FIG.
Hereinafter, the processing contents of the FMEA system 20 will be sequentially described with reference to FIGS.
In the FMEA system 20, first, a worksheet is opened. At this time, assuming that the work list 21 has already been created, the worksheet is displayed as shown in FIG. 5, for example.
In this state, as shown in FIG. 6, for example, as shown in FIG. 6, the work category designation part of the worksheet is “model / SUB (subsystem) display part”, “creation date display part”, “Model selection part”, “creation” "Worker display unit", "Nissan unit display unit (units / day)", "work No. display unit", "Element No. display unit", "work name display unit", "work action selection unit", etc. Yes.
Here, work no. For example, when “001” is input and designated for (work classification), the work name and Element No. are based on the work list 21 as shown in FIG. Is displayed.
Thereafter, the work action selection unit selects a work action. In FIG. 6, for example, “label / sponge application” is selected.

Then, based on the work action-specific failure mode / occurrence condition level file 22, as shown in FIGS. 4 and 7, the failure mode and the occurrence condition level corresponding to the work action are displayed.
In FIG. 7, “not paste”, “set position difference”, “front / back / reverse mounting”, “similar parts difference”, “insufficient holding time” are displayed as failure modes. Thus, the generation condition level is displayed in six levels. This leveling expresses quantitatively (or qualitatively) the condition (5 points) from the condition that never occurs (0 points) to the easily occurring condition (5 points) by the likelihood of work errors. The level of this occurrence condition increases as the number of steps that the operator thinks (or cares about) increases, and it is necessary to examine it based on the cause system of the collected cases.
In the present embodiment, the occurrence condition level selection unit is provided with a selection button (◎), and the occurrence condition level that best matches each failure mode can be selected interactively. Yes.
In this example, as shown in FIG. 7, for example, the following is selected.
Failure mode Occurrence condition level “No sticking” “2: Multiple different stickers are on the same surface”
“Set position difference” “1: There are two or more bumps”
“Front / back / reverse” “0: No sticking work or front / back / reverse cannot be performed”
“Insufficient hold time” “4: No hold time instruction”
Note that the occurrence condition level is not selected for the failure mode “difference in same type of parts”, and in this state, the “unconfirmed” button (◎) is selected.
When the generation condition level is selected, each level value is stored in the system as “occurrence degree (O)” (see FIGS. 3 and 4).

FIG. 7 shows a mode in which only the failure mode is displayed. For example, as shown in FIGS. 4 and 8, the failure classification is displayed together with the failure mode so that the contents of the failure mode can be grasped more accurately. You may do it.
For example, it is possible to grasp that the failure mode “Non-Paste” occurs as part of the failure category “Forget work”, so even inexperienced engineers can accurately recognize the failure category “Non-Paste”. can do.

Thereafter, as shown in FIG. 3, the outflow degree selection operation is performed in an interactive manner based on the outflow degree evaluation table 23.
In this example, as shown in FIG. 5 and FIG. 9, the outflow degree evaluation table 23 includes, for example, four stages “possible in own process”, “possible before inspecting process”, “inspecting process / in place” On the other hand, it is divided into “possible” and “impossible in the field”. On the other hand, as the degree of detection possibility, for example, three stages “a detection possibility is almost certain”, “b detection possibility is medium”, “c detection possibility The selection button (◎) is provided on both matrix frames, and either one is selected. Note that the number of points is set larger as the process is later, and an unconfirmed button (◎) is provided.
In this example, for example, when “inspection process / possible in the field” × “a possibility of detection is almost certain” is selected, for example, a failure mode “insufficient holding time” as shown in FIG. The corresponding point number “3” is stored in the system as “flow rate (D)”.

Thereafter, as shown in FIG. 3, the influence degree selection operation is performed in an interactive manner based on the influence degree evaluation table 24.
In this example, as shown in FIG. 5 and FIG. 10, the impact evaluation table 24 divides the target of the influence of the failure into, for example, three categories “function / appearance failure”, “maintenance operation failure”, and “safety failure”. In addition to providing a selection button (◎) for each, and classifying the degree of influence of each, the occurrence frequency of the influence due to the failure is classified into three stages, “a possibility is minimal”, “b possibility is to some extent”, “ c) “Generately generated”, and a selection button (）) is provided in both matrix frames to select one of them. The larger the number of points, the greater the degree of influence. In addition, an unconfirmed button (◎) is provided.
In this example, assuming that “function / appearance failure” is selected, the target of the effect is “the basic machine is unusable, repair is absolutely necessary”, and the occurrence frequency is “c surely occurred”. For example, as shown in FIG. 10, the selection button (◎) at the intersection of both of the matrix frames may be selected. In this case, for example, as shown in FIG. Is stored in the system as “influence (S)”.

Such operations of “work No. designation”, “work action selection”, “occurrence condition level selection”, “ outflow degree selection”, and “impact degree selection” Repeated every time.
After that, when “Occurrence (O)”, “Outflow (D)”, and “Influence (S)” for each failure mode are calculated, “O × D × S” is multiplied by the respective points. The “importance level calculation” is performed, and the “importance level” is calculated and stored in the system.
In particular, in the present embodiment, in consideration of the impact of quality loss cost, the countermeasure rank is weighted for each production amount (for example, the number of Nissan vehicles).
That is, when the production volume is large, it is necessary to adopt more reliable measures such as hardware measures or addition of inspection work items. Therefore, even if the importance points obtained by integrating the degree of occurrence (O), outflow degree (D), and influence degree (S) are the same, the greater the production volume, the more reliable the countermeasure is required to minimize the quality loss cost. Is done.
In the present embodiment, as shown in FIG. 11, for example, the measure rank table 25 shows the numerical range of the importance in the matrix frame of the number of Nissans and the measure rank, and the work classification designation section (see FIG. 6). When a numerical value is entered for the number of Nissan cars, countermeasure rank setting processing is performed. In this countermeasure rank setting process, the countermeasure rank table 25 is searched, the corresponding countermeasure rank is selected, stored in the system, and automatically displayed in the countermeasure rank column.

Such a series of processes is performed for each work No. As a result of being repeatedly performed every time, as shown in FIG. 3, the FMEA list 30 is created.
An example of creating the FMEA list 30 is shown in FIG.
In particular, in the present embodiment, in order to enable the FMEA list 30 to be used also as a countermeasure management table, a countermeasure column and a result re-evaluation column are further added to the FMEA list 30.

Embodiment 2
FIG. 14 shows a main part of the second embodiment of the failure mode influence analysis system to which the present invention is applied.
In the figure, the failure mode effect analysis system is a system for preventing assembly errors of products (copiers and printers) configured in substantially the same manner as in the first embodiment. It is possible to automatically display countermeasure candidates.
In the present embodiment, the failure mode effect analysis system further includes a failure mode countermeasure plan file 26 in addition to the components of the first embodiment , as shown in FIGS.
The failure mode specific measure file 26 extracts, for example, an assembly error prevention measure 33 including a measure error (failure mode) specific measure plan in advance based on the past assembly error case analysis data 32, and based on this, the failure mode is extracted. Another countermeasure plan file 26 is constructed.
Here, as an assembly error prevention measure 33, for example, as shown in FIG. 16, measure 1 (measure that does not cause a failure) and measure 2 (measure that notices the failure) for each failure mode (and failure category) corresponding to the work category. ) Are extracted as countermeasure candidates.

According to the present embodiment, the FMEA system 20 proceeds with processing according to the processing flow shown in FIG. 15 and creates the FMEA list 30.
Specifically, in the same manner as in the first embodiment, after the countermeasure rank is set, countermeasure proposal extraction processing is further performed based on the failure mode-specific countermeasure proposal file 26. For example, as shown in FIG. Then, the countermeasure plan (Countermeasure 1 and Countermeasure 2) corresponding to the failure mode is stored in the system, and the countermeasure plan is displayed as a countermeasure candidate in the FMEA list 30.
According to this aspect, since the countermeasure plan can be automatically displayed, the automatic creation range of the FMEA list 30 can be further expanded and the creation of the FMEA list 30 can be further enhanced as compared with the first embodiment. be able to.

It is explanatory drawing which shows the outline | summary of the failure mode influence analysis system which concerns on this invention. It is explanatory drawing which shows the whole structure (1) of Embodiment 1 of the failure mode influence analysis system to which this invention was applied. It is explanatory drawing which shows the whole structure (2) of Embodiment 1 of the failure mode influence analysis system to which this invention was applied. 6 is an explanatory diagram illustrating a relationship between a processing flow of Embodiment 1 and an FMEA list. FIG. 3 is an explanatory diagram illustrating a configuration of a worksheet used in Embodiment 1. FIG. It is explanatory drawing which shows the work classification display part of a worksheet. It is explanatory drawing which shows the display relationship between the failure mode of a worksheet, and generation condition level selection. It is explanatory drawing which shows the deformation | transformation form of the failure mode display part of a worksheet. It is explanatory drawing which shows the runoff degree evaluation table | surface of a worksheet. It is explanatory drawing which shows the influence evaluation table of a worksheet. It is explanatory drawing which shows the relationship between a countermeasure rank and the number of Nissan. It is explanatory drawing which shows the display relationship with the failure mode of a worksheet, a runoff degree, an influence degree, importance, and a countermeasure rank. 6 is an explanatory diagram illustrating a display example of an FMEA list obtained in the first embodiment. FIG. It is explanatory drawing which shows the principal part (equivalent to FIG. 3) of the failure mode influence analysis system which concerns on Embodiment 2. FIG. 10 is an explanatory diagram illustrating a relationship between a processing flow and an FMEA list according to Embodiment 2. FIG. FIG. 10 is an explanatory diagram illustrating an example of a countermeasure plan according to the second embodiment. It is explanatory drawing which shows an example of the investigation result of the process with a weak prevention of an assembly mistake. It is explanatory drawing which shows an example of the generation | occurrence | production state of an assembly mistake.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Control processing means, 2 ... Program medium, 3 ... Failure mode extraction part, 4 ... Mode influence analysis part, 5 ... Work classification, 6 ... Failure mode influence analysis list (FMEA list), 7 ... Occurrence condition selection part, 8 ... Association display part, 9 ... Countermeasure rank display part, 10 ... Countermeasure candidate display part

Claims (6)

Control processing means that can be controlled by a program medium, and in order to analyze the influence of failure modes based on assembly errors of products whose number of units processed per period changes , failure modes according to each work category in the control processing means A failure mode impact analysis system for creating an impact analysis list ,
The control processing means analyzes a failure mode extraction unit that extracts a failure mode corresponding to each work category corresponding to each selected work category, and analyzes the influence of the failure mode extracted by the failure mode extraction unit. Mode effect analysis unit
In the mode influence analysis unit, the degree of occurrence according to the occurrence condition level leveled for each target failure mode, the degree of outflow that sets the level at which the presence of the target failure mode can be detected, and the target failure An importance calculation unit that integrates and calculates the importance as an impact analysis result for each target failure mode using the influence set for each level of the impact on the user when shipped due to a failure caused by the mode, A failure mode effect analysis , comprising: a measure rank display section capable of displaying a rank of measures for the importance and weighted according to the number of processed products per period of the measure ranking system. In the failure mode influence analysis system according to claim 1 ,
The failure mode influence analysis system, wherein the failure mode extraction unit includes a generation condition selection unit capable of selecting generation conditions leveled for each failure mode. In the failure mode influence analysis system according to claim 1 ,
The failure mode effect analysis system, wherein the failure mode extraction unit includes an association display unit capable of displaying a failure category corresponding to a designated work category and a failure mode of each failure category in association with each other. In the failure mode influence analysis system according to claim 1 ,
A failure mode effect analysis system, wherein the mode effect analysis unit comprises a measure candidate display unit capable of displaying a measure candidate. In the failure mode influence analysis system according to any one of claims 1 to 4 ,
The failure mode extraction unit and the mode effect analysis unit are provided with an automatic processing work environment in which necessary information is displayed divided into a plurality of worksheets and linked to each other so that they can be correlated with each other. system. A computer-readable recording medium recording a program for causing a computer to function as the failure mode influence analysis system according to any one of claims 1 to 5.

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