JP2002318612A - Quality information retrieval system and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a quality information retrieval system and method capable of easily specifying a manufacture process being a cause process when any failure is generated and relevant components or the like. SOLUTION: A cause process being the possible factor of the generation of any quality failure is retrieved (S101), and components being the possible cause of the generation of the quality failure is retrieved (S102), and the quality history of the components is retrieved (S103), and the corresponding quality history of products passing in the same process before and after that is retrieved (S104), and the results are displayed. As a result, it is possible to easily recognize the transition of the quality in the process, and to easily specify the manufacture process being the possible cause process and the relevant components or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quality information retrieval system and a retrieval method, and in particular, in a manufactured product, individual process operations are performed with acceptable quality. The present invention relates to an improvement in a quality information search system and a search method capable of easily specifying a manufacturing process that can be a cause process when a defect occurs, a related part, and the like.

[0002]

2. Description of the Related Art Conventionally, in a product manufacturing factory or the like, a product to be manufactured is manufactured on a manufacturing line having a plurality of manufacturing processes such as a process of assembling parts, a process of adjusting the assembled components, and a process of performing inspection. Has been built. At this time, for each product to be manufactured, for example, the tightening torque of a bolt for attaching a part is set at an allowable torque level, a tightening time at that time, and bending processing. When performing such operations, the degree of bending within the allowable range, the amount of pressure actually applied in order to obtain the predetermined bending angle, and the problem during tightening or bending ( Various information in the manufacturing process, such as the status of a repair operation when a defect occurs, is recorded as a quality history.

[0003] For example, in an assembly and production line for an automobile engine, lines are roughly divided into a pre-assembly process, a middle assembly process, a rear assembly process, a test process, and the like.
It is divided in detail, such as one previous step, two previous steps, and so on. Each engine (semi-finished product) is mounted on a transport pallet and passes through each process. The transport pallet on which the engine is mounted has a tag for storing the quality history of each engine. For example, the transport pallet is used to load an engine (an engine block before parts are assembled) in a pre-assembly process. When put on, the production serial number assigned to each engine (identifier for identifying the individual)
Is read into the tag of the transport pallet. Then, in the pre-assembly process, the history (quality history) of the work performed on each engine is sequentially recorded on the tag. For example, in the first step, "the part X was tightened with the bolt A with the torque a"; in the previous four steps, "the oil pan was attached with the four bolts B with the torque b"; Was tightened with a torque of c using a bolt C. At this time, re-tightening was performed once ".

If the engine can be transported on the same transport pallet from the pre-assembly process to the post-assembly process, the quality history can be collected continuously. However, usually, parts are assembled to the engine sequentially. If the occupied volume increases, the pallets are sequentially replaced with transport pallets of appropriate size,
It is put into the next step, for example, the middle assembly step. Normally, at the time of this replacement work, the quality history recorded on the tag of the transport pallet moving in the preceding assembly process is transferred to a quality information processing computer via an information collection board or the like arranged at the replacement place and accumulated. Is done. The tag of the transport pallet that has moved through the pre-assembly process that has transferred the quality history to the information collection board is reset and returned to be mounted with an engine that moves to a new pre-assembly process. The transport pallet in the middle assembly process, which has received the engine for which the previous assembly has been completed, stores the manufacturing serial number in a tag and sequentially records the quality history in the middle assembly process. Hereinafter, similarly, the engine is replaced to the post-assembly process, and the collected quality history is transferred to the quality information processing computer.

[0005] The quality history collected in this manner is accumulated as quality management data of individual products, and is used for investigating the cause and taking measures when a defect occurs. For example, when an oil leak failure occurs in the engine of the serial number 12345, the quality information of the engine of the serial number 12345 is obtained by searching the data stored by the quality information processing computer based on the serial number 12345. It is possible to browse and analyze the production state of the engine that has caused the oil leak.

[0006] For example, Japanese Patent Application Laid-Open No. Hei 7-114601 discloses that a manufacturing process and manufacturing conditions are obtained as a product failure cause candidate, and whether or not the manufacturing process and manufacturing conditions are within a standard. A technique for checking from data is disclosed, and analysis on defects can be easily performed.

[0007]

A product (semi-finished product) that has passed through each manufacturing process generally satisfies the quality conditions in each manufacturing process. For example, the quality control items such as the bolt tightening value is not less than a and not more than b, the bending angle is not less than c ° and not more than d °, and the pressurizing time is not less than e second and not more than f second. Meets However, for products where multiple parts are assembled or processed in multiple processes, even if the individual quality control items are satisfied,
Failure may occur. For example, depending on the product, there may be a case in which the quality control items of each process include many items near the upper limit, or conversely, items including many items near the lower limit. Normally, tolerance values are set in consideration of these situations. However, in a product that is composed of multiple parts and is completed through multiple processes, it occurs due to a combination of quality variations (the quality of each process is satisfied). It is difficult to completely eliminate defective products. In particular, "Noise is generated throughout the product" and "There is a trace of oil leakage around the bottom surface" are different from defects that can be visually confirmed, such as component mounting errors and joining errors. It is difficult to identify. In addition, even if the quality history of the process that causes the defect is presented and compared with the reference value, it is within the allowable range in the quality history, so it is impossible to specify it as a specific cause It is.
In such a case, it is usually necessary to extract a process considered to be a cause from the quality history based on the experience and intuition of the person in charge and individually confirm the process. As a result, there is a problem that a great deal of time is required until the cause is investigated, and the required time and accuracy vary greatly depending on the skill of the person in charge.
Difficult “oil leaks”, especially in identifying locations that cause defects
In the search for “unusual noise” or “unusual noise”, the above-mentioned variation appears remarkably.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and in a manufactured product, individual process operations are performed with acceptable quality, but defects occur due to the interaction of the operation quality in each process. It is an object of the present invention to provide a quality information search system and a search method capable of easily specifying a manufacturing process, a related part, and the like that can be a cause process in the case of performing the search.

[0009]

In order to achieve the above object, the present invention provides a history storage means for storing an identifier assigned to a product to be manufactured and a quality history at the time of manufacturing the product. A cause process storage means for associating and storing the content of the quality defect occurring in the product and a cause process that may cause the quality defect, and associating the cause process with the parts used in the cause process. Parts storage means for storing, first search means for searching at least a cause step of the quality defect and parts used therein based on the input of the identifier of the product and the contents of the quality defect, and a search by the first search means Second search means for searching the quality history of the used parts and the quality history of the parts used within a predetermined number of times before and after the same process, and at least the first search means and the second search means And presenting means for presenting also shown the retrieved quality history, characterized in that it comprises a.

[0010] In order to achieve the above object, the present invention provides a history storing step of storing an identifier assigned to a manufactured product and a quality history of the product at the time of manufacturing; A process storage step of associating and storing the content of the quality defect to be caused and a cause process that may cause the quality failure, and a component storage step of associating and storing the cause process with a component used in the cause process A first search step of searching for at least the cause process of the quality defect and the parts used therein based on the input of the identifier of the product and the content of the quality defect; A second search step of searching for a quality history related to a part used within a predetermined number of times before and after the step of searching, and a presentation step of presenting the searched quality histories together. Law, characterized in that.

Here, the identifier is, for example, a production serial number or the like, and can identify each product. In addition, the quality history includes the work status in the manufacturing process of the target product, for example, bolt tightening result, bending angle result, working time result, presence / absence and content of repair (correction), and the like. As for the quality defect, the content of the defect predicted from the past results or the like is additionally stored as appropriate. Further, a cause process that may cause a quality defect is also associated with the content of the quality defect based on past results. Note that the components used in the cause process include, in addition to the components of the product to be specifically attached, additional materials used for joining and the like, for example, screws, sealants, solders, and the like.

[0012] According to this configuration, a cause process that can cause the occurrence of a quality defect, a component that can cause a quality defect, and a quality history of the component are presented.
Since the corresponding quality history of the product that passed the same process before and after that is also presented, the change in quality in that process can be easily recognized, and the manufacturing process and related parts that can be the cause process can be easily identified. Can be specified.

[0013] In order to achieve the above object, the present invention is characterized in that, in the above configuration, the first search means searches a plurality of candidates for a cause process which may cause a quality defect.

In a product manufactured through a combination of a plurality of parts or through a plurality of steps, the accumulation of the slight influence of each step may cause a defect. For this reason, the cause process candidates can be presented with priorities, for example, from the process having the highest influence.

According to this configuration, it is possible to improve the accuracy of specifying a manufacturing process, a related component, and the like that can be a process causing a defect.

In order to achieve the above object, the present invention, in the above-described configuration, further includes information searching means for searching for manufacturing regulation information in a cause process which may cause the searched quality defect. The regulation information is presented together with the presentation means.

Here, the manufacturing regulation information indicates, for example, standard work contents in the process such as a work procedure manual and a quality check manual in the process.

According to this configuration, it is possible to easily recognize the transition from the standard work and the like, and it is possible to contribute to the planning of the defect.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings.

FIG. 1 is a system configuration diagram illustrating the configuration of a quality information search system 10 (hereinafter, referred to as a system 10) of the present embodiment. In the case of this embodiment,
An example in which a search system is applied to an engine manufacturing line will be described using a car engine as an example of a product to be manufactured.

The engine production line includes, for example, “pre-assembly step 12”, “middle assembly step 14”, “rear assembly step 16”,
Each of the large steps is further divided into steps for performing a plurality of related operations, for example, “one step before”, “two steps before”, “three steps before”, and so on. And so on. The production line of FIG. 1 is configured to be temporarily stored in the “stock shelf 20” after the end of the test process.

As shown in FIG. 1, information collecting boards 22a to 22d are arranged between the major steps. As described above, in the engine manufacturing line, each engine (semi-finished product) is mounted on a transport pallet and passes through each process. The transport pallet on which the engine is mounted has a tag for storing the quality history of each engine. For example, in order to load an engine (an engine block before parts are assembled) into the pre-assembly process 12, the transport pallet has a tag. When placed on a pallet, the production serial number assigned to each engine (an identifier for identifying an individual, for example, "0014
3 ") is read into the tag of the transport pallet, and the histories (quality histories) of the work performed on the individual engines in the pre-assembly step 12 are sequentially recorded in the tag. Then, "the part X was tightened with the bolt A with the torque a". In the preceding four steps, "the oil pan was attached with the four bolts B with the torque b". At this time, re-tightening was performed once ".

Normally, when components are sequentially assembled to the engine to increase the occupied volume, the pallets are sequentially replaced with transport pallets of an appropriate size. Further, there is a case where the transfer pallet needs to be replaced depending on the working position with respect to the engine. For example, in the previous assembling step 12, the work on the upper surface side of the engine is performed, but in the middle assembling step 14, the work on the lower surface side is performed. In such a case, the replacement is performed, and the next process, for example, the middle assembly process 14
It is thrown into. Usually, at the time of this replacement work,
The quality history recorded on the tag of the transport pallet that moves through 2 is collected by the information collection panel 22a disposed at or around the replacement site. The tag of the transport pallet that has moved through the pre-assembly process 12 that has transferred the quality history to the information collecting panel 22a is reset and returned to mount an engine that moves on to the new pre-assembly process 12. Further, the transport pallet of the middle assembly process 14 which has received the engine for which the previous assembly has been completed has an engine manufacturing serial number (for example, “00”) in the tag.
143 "), and sequentially records the quality history in the middle assembly process 14. Similarly, when the engine is changed to the rear assembly process 16, the quality recorded in the middle assembly process 14 by the information collecting panel 22b is similarly calculated. The information collecting panel 22c collects the quality history recorded in the post-assembly step 16, and the information collecting panel 22d collects the quality history recorded in the test process.The information collecting panels 22a to 22d collect the history. The quality history collectively manages the entire system 10 and, in the present embodiment, a search unit (the first unit) that searches for characteristic quality information.
The information is appropriately transferred to the quality information processing computer 24 including the search means and the second measure means, and further stored in the database of the server A26 which stores and manages various information.

In the present embodiment, the server A 26
A quality history database (quality history DB; history storage means) 28 for storing the quality histories collected by the information collection boards 22a to 22d and the like in association with the manufacturing serial number is constructed. The server A 26 stores a cause process database (cause process DB; cause process storage means) 30 in which the content of the quality defect occurring in the engine (product) and the cause process that can cause the quality defect are associated and stored. Has been built. It is preferable that the cause process DB 30 accumulates the past failure results of the same product, and the work or the process using the component that causes the failure obtained by analyzing the failure in association with each other. . For example, in the case of an engine, for example, as a quality defect that has occurred in the same product in the past, for example, "oil leak", "abnormal noise", "vibration"
Etc., and as a cause process that can be a cause, for example,
As a countermeasure for "oil leakage", "one step before:
The "corresponding to the bolt A tightening step" and the "abnormal noise" include "the preceding three steps: assembling of the part A". As a specific structure of the cause process DB 30, as shown in FIG. 2A, “candidate 1”, “candidate 2”, “candidate 3”, and the like are set as candidates for the cause process with respect to “defective contents”. For each of the “defective contents A”, “candidate 1: previous one step”, “candidate 2: previous two steps”, “candidate 3: previous four steps”,
“Candidate 1: middle one step”, “candidate 2: middle five step”, “candidate 3: middle eight step” and the like are associated with “defective content B”. Note that the number of associated cause steps differs depending on the content of the defect.

Further, in addition to the cause process and the components used in the cause process, the engine components to be specifically mounted, and the additional materials (for example, screws, sealants, solder, etc.) used for joining, etc. And a related component database (component DB; component storage means) 32 which is stored in association with the relevant component. This part DB32
Is constructed based on manufacturing specification information and the like provided from a higher-level production management system or the like. Specifically, FIG.
As shown in (1), "Part A" is associated with "Previous Step 1," and "Part B" is associated with "Previous Step 2." In addition, when the process of attaching parts or the like is switched or the parts are changed, the changed contents are immediately reflected. As another data structure, as shown in FIG. 2C, a "correspondence table" may be constructed by associating "defective contents" with "parts".

In this embodiment, an accessible server B34 is connected to the quality information processing computer 24. In the server B34, a database storing work contents (manufactured specification information in this embodiment) defined for each manufacturing process is constructed, and an information search unit (information search means) inside the quality information processing computer 24 is constructed.
Is searchable. More specifically, a work procedure DB 36 that stores work procedures and a check standard DB 38 that stores quality check standards. The work instructions are
Items that the field workers should work in the process are listed in the order of work. In addition, it describes, as a standard, how much time is required to be performed in each operation within one cycle tact time. In addition, the quality check standard indicates a place where a site worker should perform a quality check in the process, and, for example, when the size to be checked is a dimension, a reference value and an allowable range are described. I have. Note that the system 10 in the present embodiment
Is connected to a printer 40 as a means for presenting searched information and the like. Of course, it is also possible to present information on a display device to which the quality information processing computer 24 is connected. In FIG. 1, the quality information processing computer 24 and each server A2
6, the configuration in which the server B34 and each database are separated is shown, but the quality information processing computer 24 may include all of them. Further, if necessary, an arbitrary server or database may be connected to enable the quality information processing computer 24 to search. The data in each database can be updated as appropriate, and it is preferable that the latest data be stored.

A procedure for searching for quality information by the system 10 configured as described above will be described with reference to the flowchart shown in FIG. First, as a result of the test in the test process 18, when a defect (for example, oil leakage, vibration, abnormal noise) is found, or when a defect is found in a subsequent process (a process of combining with another product, etc.), The quality manager inputs the manufacturing serial number of the product (engine) in which the defect was found and the content of the defect from the input screen of the quality information processing computer 24 (S100). The quality information processing computer 24
An input screen as shown in FIG. 4 is displayed on the display device, and a serial number and contents of a defect can be input using a keyboard and a mouse. At this time, if a defective part can be identified, a defective part, for example, a head, a connecting rod, an oil pan, etc., or if unknown, an unknown or the like may be input. In addition, leakage, abnormal noise, vibration, and the like can be input for the content of the defect. Although the example of FIG. 4 shows an example in which the input of the defective part or the content of the defective is performed by the pull-down method, it may be directly input by a free word.

When the quality information processing computer 24 receives basic information relating to the defect, that is, the input of the manufacturing serial number and the content of the defect, or operates the search key in FIG.
With reference to the B30 and the parts DB 32, a search is made for the corresponding cause step of the quality defect and the parts used there (S10).
1, S102). The search for the cause process and the corresponding part is executed by a first search unit (first search unit) in the quality information processing computer 24. As shown in FIGS. 2A to 2C, the content of each defect, the cause process, and the parts used there are related by the correspondence table, so that the search can be easily executed.

Subsequently, the second search unit (second search means) of the quality information processing computer 24 stores the quality history DB 28
Based on the input manufacturing serial number and the part searched by the first search unit, a quality history and a use history of the corresponding part in the corresponding step are searched (S103) and used within a predetermined number of times in the same step. A quality history of the part thus obtained is searched (S104). Further, if necessary, a search for the manufacturing regulation information of the corresponding process is executed (S105). As described above, of the production regulation information, the work procedure document is obtained by searching the work procedure DB 36 based on the process searched in (S101). Similarly, the quality check standard is obtained by searching the check standard DB 38.

Then, the quality information processing computer 24
Displays the searched data sequentially on the display device (S106). FIG. 5 shows a display example of the search result. For example, the manufacturing serial number, the defective part, the content of the defect, and the like input in (S100) and the like are displayed.
The cause process searched in is presented as a candidate. As described above, the failure may be caused by a single cause, or may be caused by a combination of a plurality of causes.
Further, even if the same defect occurs in a single process, there may be a plurality of processes that may cause the same. In such a case, each process needs to be presented as a possible process candidate. In the present embodiment, the steps are presented in order from the step having the highest degree of relevance to the defect. As a result, it is possible to appropriately and efficiently execute the analysis of the cause of the failure and the subsequent measures.

As shown in FIG. 5, the retrieved quality history is first entered in the center with the manufacturing serial number that triggered the defect discovery, that is, the one entered in (S100) (for example, 00).
1453) and the corresponding quality history are displayed. At this time, in order to distinguish the relevant manufacturing serial number and quality history from other manufacturing serial numbers and manufacturing history, and to make it easier for the quality manager to visually recognize it, for example, surround it with a distinguishing line or change the display color. And it is preferable to add a mark. FIG.
In the case of, an example surrounded by a distinguishing line is shown.

In the upper row, a production serial number (prior to 001452) and a quality history of a product performed before the production are displayed. Similarly, the lower row displays the serial number of the product (001454 or later) and the quality history of the product performed after the manufacture. The number of displays before and after the display at this time is arbitrary, but it is preferable to display a number in which the transition of the quality history can be recognized, for example, 20 to 30 quality histories. By performing such a search display of the related quality history before and after, it is possible to grasp, for example, a change in the tightening value of the bolt. That is, when the tightening torque value is 9 to 10 Nm in the operation manual, the tightening was performed at 9.5 Nm in the quality history of the front and rear products. If a quality history indicating that the product of 0001453 was tightened at 9.1 Nm remains, the work in this step is acceptable because a value within the allowable range has been obtained. With respect to other products, the fact that the tightening torque is low can be presumed to be one of the complex factors of failure occurrence. In addition, when a decrease in the tightening torque is confirmed as a whole by referring to a plurality of histories, performance degradation of the tightening device may be considered. As described above, by displaying the related quality history, it is possible to efficiently and easily analyze the quality information. Of course, system 1
As a function of “0”, a change in the quality history may be detected to automatically determine whether or not the cause is a defect.

In FIG. 5, by operating the "cause process candidate" pull-down key, the quality history of the next candidate process can be displayed.
The quality history in the process is displayed, and the transition of the quality history can be confirmed.

In order to display the manufacturing regulation information in the corresponding step, when the "next" key in FIG. 5 is operated,
For example, a work procedure and a quality check standard as shown in FIG. 6 are displayed. Of course, a window for the work procedure and the quality check standard may be formed in FIG. 5 and displayed at the same time.

By analyzing the search result display of FIG. 5, the quality manager determines whether or not the presented process candidate includes a process causing a defect (S107). If it is determined that there is a defect cause during the candidate process, it is determined whether or not to update each of the databases 28 to 32 based on the result (S108). That is, it is determined whether or not the result of the current failure search is to be reflected in the database. For example,
In the case of a sudden occurrence, the result itself leads to a decrease in the accuracy of the database, so that the cause is eliminated. When the database is updated (S109), it is desirable that the update history is also stored.

The quality information processing computer 24 confirms whether or not to print the searched result irrespective of whether or not the database has been updated (S110). And print the result (S
111). If printing is not to be performed, the search process is terminated.

On the other hand, if no defect cause is found in the process candidates (S107), the quality information processing computer 24 switches to the manual search mode. That is, the date of manufacture is input together with the manufacturing serial number (S112), and the second
The search unit searches the production history DB 28 and displays a list of the quality histories of the corresponding products (S113). The quality manager analyzes the displayed quality history and selects a process that caused the defect (S114). Thereafter, the quality information processing computer 24 requests a selection as to whether or not to perform the production regulation information search (S115). If the selection of the production regulation information is not performed, the process proceeds to (S108) to update each database. After the selection of the necessity and the presence / absence of printing is made, the search process is terminated. Further, when selecting the production regulation information, the work procedure DB 36 and the check standard DB 38 are searched to obtain the work procedure and the quality check standard (S116), and after displaying them on the display device (S117), (S108) Then, the user is allowed to select whether or not to update each database and whether or not to print, and then terminates the search process.

As described above, the cause process which can cause the occurrence of the quality defect, the component which may cause the quality defect, and the quality history of the component are presented, and the same process is performed before and after that. In addition to presenting the corresponding quality history of products that have passed, it is possible to quickly investigate the cause of defects and reduce the required time and accuracy variations due to the skill of the quality manager. Will be possible.

In the present embodiment, the configuration of the system 10 shown in the figure is a simplified example.
Furthermore, a plurality of manufacturing processes, databases, and servers are connected, and various information searches can be performed.

The display screens shown in FIGS. 4 to 6 are also examples, and the display contents can be changed as appropriate.

[0041]

According to the present invention, a cause process that can cause the occurrence of a quality defect, a component that can cause a quality defect, and a content of the quality history of the component are presented. Since the corresponding quality history of the product that passed the same process before and after that is also presented, the change in quality in that process can be easily recognized, and the manufacturing process and related parts that can be the cause process can be easily identified. Can be specified.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram illustrating a configuration of a quality information search system according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating an example of a correspondence table describing a structure of a database of the quality information search system according to the embodiment of the present invention.

FIG. 3 is a flowchart illustrating a quality information search procedure of the quality information search system according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram illustrating an example of a search input screen of the quality information search system according to the embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating an example of a search result screen of the quality information search system according to the embodiment of the present invention.

FIG. 6 is an explanatory diagram illustrating a display example of manufacturing regulation information of the quality information search system according to the embodiment of the present invention.

[Explanation of symbols]

1 Quality information search system, 12 pre-assembly process, 14 middle assembly process, 16 rear assembly process, 18 test process, 20 stock shelf, 22a-22d information collecting board, 24 quality information processing computer, 26 server A, 28 quality history database , 30 cause process database, 32 related parts database, 34 server B, 36 work procedure database, 38 check standard database, 40 printer, S100 to S117 search processing step.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroshi Yamamoto 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F-term (reference) 3C100 AA57 AA58 AA59 BB27 CC08 DD12 DD22 DD25 EE01

Claims (4)

[Claims] 1. A history storage means for storing, together with an identifier given to a product to be manufactured, a quality history at the time of manufacturing the product, contents of a quality defect occurring in the product and a cause of the quality defect. Cause process storage means for associating and storing the cause process, component storage means for associating and storing the cause process and the parts used in the cause process, input of the product identifier and the content of the quality defect Based on
A first search means for searching for at least a cause step of the quality defect and a part to be used therewith; a quality history at the time of use of the part searched by the first search means; and a part used within a predetermined number of times before and after the same step. A quality information search system comprising: a second search unit that searches for a quality history; and a presentation unit that presents at least the quality history searched by the first search unit and the second search unit. 2. The quality information search system according to claim 1, wherein said first search means searches a plurality of candidates for a cause process which may cause a quality defect. 3. The system according to claim 1, further comprising information searching means for searching for manufacturing specification information in a cause process which may be the cause of the searched quality defect, and presenting said manufacturing specification information. A quality information retrieval system characterized in that it is presented together with the information. 4. A history storing step of storing, together with an identifier assigned to a manufactured product, a quality history at the time of manufacturing the product, the content of the quality defect occurring in the product and the cause of the quality defect. A process storing step of associating with the cause process and storing; a component storing step of associating and storing the cause process and the parts used in the cause process; and inputting the product identifier and the content of the quality defect. Based on
A first search step of searching for at least the cause process of the quality defect and a part used therein, and a second search for searching the quality history of the searched part at the time of use and the quality history of the part used within a predetermined number of times before and after the part. A quality information search method, comprising: a search step; and a presentation step of presenting together the searched quality histories.