JP2019113994A - Work-piece failure cause specification method - Google Patents

Abstract

To provide a work-piece failure determination method capable of clearly specifying a failure cause.SOLUTION: According to this invention, a work-piece failure cause specification method includes a plurality of production steps for processing a work-piece, and conveyance steps for conveying the work-piece from a prescribed production step to the next production step, determines the quality of the work-piece by inspecting the work-piece undergoing respective steps, and specifies the cause of a failure of a work-piece determined to be a failure. Processing condition data related to processing executed in each step is acquired for each work-piece, processing condition data of each step to the work-piece determined to be a failure is extracted from the processing condition data, and the cause of the failure is specified on the basis of the extraction data. The processing condition data includes conveyance related time data about a conveyance related time including conveyance times of the work-piece in the conveyance steps.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for identifying the cause of a defect in a workpiece, and related techniques, which identify the cause of the defect when it is determined that the workpiece produced by performing a predetermined process is defective.

  In an electrophotographic system such as a copying machine, a printer, a facsimile, and a complex machine thereof, a cylindrical body such as a photosensitive drum base used as a photosensitive drum is, for example, a long tubular body made of an aluminum alloy which is extruded or drawn. It is manufactured by cutting a (raw pipe) into a predetermined length. As shown in Patent Document 1 etc., the quality of the cut cylindrical body (divided product) is judged by various tests, and the passable product and the reject product are judged based on the test result. It is like that.

  On the other hand, not limited to the photosensitive drum substrate, in order to suppress the occurrence of defective products and effectively improve the production efficiency (yield) and reduce the cost, the cause of the defect is identified and the defect cause is identified. It is essential to remove it from the production line. Therefore, conventionally, for example, when traceability is introduced and a defective product is generated, processing conditions (processing status), such as what processing has been performed in each process in the manufacturing process of the defective product, are displayed. Many methods are retroactively investigated to identify the cause of failure.

JP 2004-345051

  Heretofore, in the method of manufacturing a base for a photosensitive drum as described above, when identifying the cause of defect, the cause of defect is mainly referred to processing conditions in the processing step, for example, drawing force at drawing and pressure at cutting. I try to identify.

  However, the causes of defects include various factors, and many causes of defects that have not yet been investigated remain. For this reason, it may not be possible to clearly identify the cause of defects conventionally, and in such a case, it becomes difficult to improve the manufacturing line, and there is a problem that it is difficult to improve productivity and reduce costs. The

  The present invention has been made in view of the above problems, and can identify a cause of defect more clearly, can improve productivity and can reduce cost, and a method for identifying a defect cause of a work and related items The purpose is to provide technology.

  In order to solve the above-mentioned subject, the present invention is provided with the following means.

[1] A plurality of production processes for processing the workpiece, and a transport process for transporting the workpiece from a predetermined production process to the next production process, and inspection is performed on the workpiece obtained through the above-described respective processes to determine whether it is good or not In the method of identifying the cause of a defect of a work, in which the cause of the defect of the work determined to be a defect is identified as well as the determination
Processing condition data on the processing performed in each step is acquired for each work, and processing condition data of each step for the work determined to be defective is extracted from the processing condition data, and the extracted data is extracted. While identifying the cause of failure based on
A method for identifying a defect cause of a workpiece, wherein the processing condition data includes transport related time data related to transport related time including a transport time of the workpiece in the transport step.

[2] A plurality of transport steps are provided,
The method for identifying a defect cause of a work according to the preceding paragraph 1, wherein a total of transfer times in at least two or more transfer steps among the plurality of transfer steps is set as a transfer related time.

[3] A plurality of transport steps are provided,
3. The method according to claim 1 or 2, wherein the transfer related time is a total of all transfer times in the transfer process.

  [4] The time required for processing the work in each production step is taken as the processing time, and at least one or more of the processing times are included in the transfer related time. The method for identifying the cause of defects in workpieces described in Section 1.

  [5] The production process includes at least one or more of a heat treatment process of performing a heat treatment on the workpiece, a drawing process of performing a drawing process, a cutting process of performing a cutting process, and a cleaning process of performing a cleaning process. The defective cause identification method of the workpiece according to any one of the preceding items 1 to 4.

[6] The average value of the transfer related time of all the workpieces to be processed is taken as the transfer related time average value,
The defect cause of the work according to any one of the preceding items 1 to 5, wherein the transfer related time data of the work determined to be defective is collated with the transfer related time average value to identify the cause of the defect of the work. Specific method.

[7] A plurality of production processes for processing the workpiece and a transport process for transporting the workpiece from a predetermined production process to the next production process are included, and the quality of the workpiece obtained through each process is judged How to judge the quality of work,
A workpiece characterized in that the cause of failure is specified in advance by the method for specifying the cause of failure of a work described in any one of items 1 to 6 above, and the quality of the work is judged based on the cause of failure. Judgment method of

  [8] Process condition data regarding the process performed in each process is acquired for each work, and the cause of failure is configured from among the works that have passed through each process by referring to the process condition data. The work quality determination method according to item 7, wherein a work on which the same process as the process condition is performed is selected, and the selected work is determined to be defective.

[9] A plurality of production process units that process workpieces, a transport unit that transports the workpieces from a predetermined production process unit to the next production process unit, and quality inspection performed on the produced workpieces to determine whether they are good or not In a traceability system provided with means and defect cause identification means for identifying the cause of the defect of the work judged to be defect,
The defect cause specifying means acquires, for each work, processing condition data related to the process carried out in the production process unit and the conveying means, and the processing condition data of each process for the work determined to be defective among the processing condition data. Configured to extract processing condition data and identify the cause of failure based on the extracted data;
The traceability system according to claim 1, wherein the defect cause identification unit is configured to acquire, as the processing condition data, transfer related time data related to a transfer related time including a transfer time of the work by the transfer unit.

[10] A plurality of production process units that process the workpiece, a transport unit that transports the workpiece from a predetermined production process unit to the next production process unit, and quality inspection performed on the produced workpiece to determine whether it is good or not Means for judging whether the work is good or bad
The quality determination system for a workpiece according to claim 9, wherein the quality determination unit is configured to determine the quality of the workpiece based on the cause of the defect specified in advance by the traceability system according to item 9.

  According to the defect cause identification method of the work of the invention [1], the transfer time of the transfer step is set as a candidate for the defect cause, and the defect cause is specified based on the transfer related time data including the transfer time. It is possible to clearly identify the cause of failure related to the transport time which could not be clarified conventionally.

  According to the defect cause identification method of a work of the inventions [2] to [6], the above-mentioned effect can be obtained more surely.

  According to the method for determining the quality of a work of the inventions [7] and [8], the quality of the work is determined based on the causes of defects of the inventions [1] to [6]. It can be further improved.

  According to the traceability system of the invention [9], the same effect as that of the method invention described above can be obtained.

  According to the workpiece quality determination system of the invention [10], the inspection accuracy of the workpiece can be further improved as described above.

FIG. 1 is a block diagram showing each step in the process of manufacturing a cylindrical body in which the method for identifying the cause of defects in a work according to the embodiment of the present invention is adopted. FIG. 2A is a view for explaining a first conveying step and a heat treatment step in the manufacturing process of the long cylinder of the embodiment. Drawing 2B is a figure for explaining the 1st conveyance process and heat treatment process in the manufacture process of the short cylindrical object of an embodiment. FIG. 3A is a view for explaining the drawing process and the third transfer process in the manufacturing process of the long cylindrical body of the embodiment. FIG. 3B is a view for explaining the drawing step and the third transfer step in the process of manufacturing the short cylindrical body of the embodiment. FIG. 3C is a graph for explaining the relationship between the processing time and the drawing force in the drawing process of the embodiment. FIG. 4A is a view for explaining a cutting process and a cleaning process in the manufacturing process of the long cylinder of the embodiment. FIG. 4: B is a figure for demonstrating the cutting process in the manufacture process of the short cylinder of embodiment, and a washing | cleaning process.

<Overview of manufacturing process>
FIG. 1 is a block diagram showing each step of a manufacturing process of a cylindrical body in which a method for identifying a cause of defect of a work according to an embodiment of the present invention is adopted. As shown in the figure, the cylindrical body (tubular body) manufactured in the present embodiment is, for example, a photoconductive drum, a transfer roller, and the like in a copying machine, a printer, a facsimile, and a composite machine etc. Is used for each part of

  As shown in FIG. 1, when manufacturing a cylindrical body in the present embodiment, a first conveying step of conveying a raw material pipe, which is a carried-in material, to a heating device (heating furnace) by a conveyor (conveying device); Heat treatment process to heat and radiate heat from the raw pipe, second conveyance process to convey the heat treated raw pipe to the drawing device (drawing apparatus) by the conveyor (conveying device), diameter reduction processing of the end of the raw pipe ( A drawing process in which the raw pipe is subjected to drawing processing by a drawing device, a third conveying process in which the raw pipe after drawing processing is conveyed to a cutting device by a conveyor (conveying apparatus), and the raw pipe is cut Cutting process to obtain a plurality of divided products (cylindrical bodies) by a device, a fourth conveying process of conveying the cut divided bodies (cut products) to a cleaning device by a conveyor (conveying apparatus), divided products (cylindrical Wash the body) And it includes a cleaning step of cleaning, and a fifth transport step of discharging the washed cylinder by. Then, a product inspection (inspection on a divided product) is performed on the processed cylindrical body, and the quality is determined.

  In the present embodiment, the respective conveying devices (first to fifth conveying devices) in the first to fifth conveying steps constitute conveying means, and the heating device, the drawing device, the cutting device, and the cleaning device are production process parts. Is what constitutes Furthermore, in the present embodiment, the production process is configured by the heat treatment process, the drawing process, the cutting process, and the cleaning process, and the production process does not include the product inspection (inspection process).

  Further, in the present embodiment, each drive unit of the first to fifth transport processes of each transport device, heating device, extraction device, cutting device, cleaning device, automatic inspection device, and control device C1 configured by a microcomputer etc. Is controlled to perform various processes in each process. Furthermore, each control device C1... Is connected to an information database DB1 and a trace database DB2. The information database DB1 holds information (processing condition data) on processing conditions (conditions) in each process as described later, and the trace database DB2 divides work (element pipe) as described later. Information (pre- and post-division position data) and the like regarding the positional relationship between the front and back is held. Then, product inspection is performed based on the information held in the databases DB1 and DB2.

  In the present embodiment, a main control device such as a host computer may be provided to integrally control the control devices C1... Managing the respective processes.

  Further, in the present embodiment, two databases of information database DB1 holding information on processing conditions and trace database DB2 holding information on trace information are used. However, the present invention is not limited thereto. The above information may be integrated and managed by one database, or may be divided into three or more databases as appropriate.

  Further, in the present embodiment, the work includes all the raw tube before cutting, the cut product after cutting and the cylinder as a divided product, and the final product.

  Furthermore, in the present embodiment, the databases DB1 and DB2 function as transport related time holding means.

<1st conveyance process>
FIGS. 2A and 2B are diagrams for explaining a first conveying step and a heat treatment step in the manufacturing process of the long cylinder and the short cylinder. In FIG. 2A and FIG. 2B, the broken line drawn on the raw pipe (work) W1 indicates the position corresponding to the cutting position of the raw pipe W1 in the cutting step of the post process (FIG. 3A, FIG. 3B below) , Same as in FIG. 4A and FIG. 4B).

  As shown to FIG. 2A-FIG. 2B, raw pipe W1 conveyed in a 1st conveyance process is comprised by the extrusion pipe etc. which are made, for example of aluminum alloy.

  In the first conveyance step, the raw pipe W1 is sequentially conveyed by the conveyor (first conveyance device) toward the heating device (heating furnace) 2 in the heat treatment step.

  In the present embodiment, an individual number (ID number, serial number) is given to the raw pipe W1 to be transported.

  In addition, the control device C1 (see FIG. 1) in the first transfer step can acquire the individual number of the transfer pipe W1 to be transferred, and the transfer pipe W1 performs the first transfer based on information from various sensors, timers, etc. It is possible to calculate a time (conveyance time) from the time of being carried into the apparatus to the conveyance to the heating furnace 2 of the next process (heat treatment process). The transport time for each raw pipe W1 thus acquired is held as information related to transport related time (processing condition data) in the information database DB1 by the control device C1, and for any raw pipe W1 processed when necessary. Even in this case, the information (processing condition data) can be extracted from the information database DB1.

<Heat treatment process>
As shown in FIG. 2A and FIG. 2B, in the heat treatment in the heat treatment step, the heating furnace 2 is batchwise heated collectively for every predetermined number of raw pipes W1, and the raw pipe W1 is sequentially passed through the heating furnace 2 There is a case where it is carried out by a continuous method of heating while heating.

  In the present embodiment, heating is performed in a continuous manner. Further, the control device C1 for the heating furnace 2 can acquire the individual number of the raw pipe W1 to be processed, and can acquire the temperature in the furnace based on the information from the temperature sensor. Furthermore, the control device C1 can calculate the time (heat treatment time) for the base pipe W1 to pass through the heating furnace 2 based on information from various sensors, timers, and the like. The control device C1 holds the information on the heating time and heating temperature for each raw pipe W1 thus acquired in the information database DB1, and further, the information (for any raw pipe W1 processed when necessary) Processing condition data) can be extracted from the information database DB1.

  On the other hand, in the present embodiment, after passing through the heating furnace 2, the base pipe W1 is subjected to a heat release process to lower the base pipe temperature to a predetermined temperature. In the present embodiment, this heat release treatment is also handled as part of the heat treatment process.

<2nd conveyance process>
In the second transfer step, the raw pipe W1 subjected to the heat release treatment in the heat treatment step is sequentially transferred by the conveyor (second transfer device) to the extraction device of the extraction step.

  Further, the control device C1 in the second transfer step can acquire the individual number of the transfer pipe W1 to be transferred in the same manner as described above, and the transfer pipe W1 is transferred to the second transfer device based on information from various sensors, timers, etc. It is possible to calculate the time (conveying time) from the time of loading to the time of conveyance to the extraction device. The transport time for each raw pipe W1 thus acquired is held as information related to transport related time (processing condition data) in the information database DB1 by the control device C1, and for any raw pipe W1 processed when necessary. However, the information can be extracted from the information database DB1.

<Pulling process>
As shown in FIG. 3A and FIG. 3B, in the drawing process, the inside of the drawing die 3 is clamped in a state in which the mouthpiece processing section W0 of the raw pipe W1 having the mouthing processing section W0 formed at the tip end by mouthing processing By passing it, it is processed so as to be stretched while reducing the diameter. In this drawing process, by measuring the pressure (drawing force) at the time of pulling the raw pipe W1, it is possible to simply evaluate the quality of the load applied to the raw pipe material.

  On the other hand, by performing the drawing process, the raw pipe W1 extends and the length dimension and the diameter dimension change, but the rate of change (the rate of deformation) such as the rate of change in extension or the rate of change in diameter is a design value. Since it is constant, the length after drawing processing can be correctly computed from the length before drawing processing in raw pipe W1.

  In the present embodiment, the control device C1 (see FIG. 1) of the drawing apparatus can acquire the identification number of the raw pipe W1 to be processed, and is required for drawing based on information from various sensors, timers, etc. It is possible to obtain the required time (extraction time). Furthermore, in the present embodiment, as shown in FIG. 3C, it is possible to acquire the temporal change of the tensile pressure from the extraction start time point to the extraction time point of the raw pipe W1 to be processed. Then, based on these pieces of information, information (tensile pressure information at each position) is calculated at which position (portion) of the raw pipe W1 is applied to which position (portion) for each raw pipe W1 after the drawing processing. This information is stored in the information database DB1. When necessary, tensile pressure information and extraction time information for each part can be cut out from the information database DB1 for any processed raw pipe W1.

  Further, in the present embodiment, as shown in FIG. 3C, the control device C1 can detect whether chattering vibration occurs during drawing based on information from a vibration sensor installed in the drawing processing apparatus. ing. Furthermore, when a chattering vibration occurs, it is possible to calculate information on which position of the raw pipe W1 after machining a chattering defect has occurred based on the elapsed time from the start of drawing, and the information Are held in the information database DB1. In the present embodiment, the information on the occurrence position of chattering, the above-mentioned tensile pressure information and drawing time information for each raw pipe position constitute processing condition data.

  In the present embodiment, each position (each part) of the raw pipe W1 after drawing processing corresponds to any position (part) of the raw pipe W1 before drawing processing based on the elongation rate (rate of change) by drawing processing. It is made to calculate the information (the corresponding position information before and after pulling out). Here, the elongation rate due to the drawing process slightly changes depending on various factors such as the material of the raw pipe, the drawing die, and the tolerance of the processing conditions, but by using the formula taking into consideration the predetermined tolerance, the after drawing process It is possible to accurately grasp which position before drawing corresponds to each position. Further, if the length of the raw pipe is measured using a sensor or the like after the drawing processing, the corresponding positions before and after drawing can be more accurately grasped based on the actual measurement value.

  In the present embodiment, the calculated corresponding position information before and after withdrawal is held in the trace database DB2. When necessary, it is possible to cut out, from the trace database DB2, information on which position (portion) after drawing processing corresponds to which position before drawing processing for any of the drawn raw pipe W1. It is supposed to be.

<Third Transfer Step>
In the third conveyance step, the raw pipe W1 after being drawn is sequentially conveyed by the conveyor (third conveyance device) to the cutting device in the cutting step.

  Further, the control device C1 in the third transfer step can acquire the individual number of the transfer pipe W1 to be transferred in the same manner as described above, and the transfer pipe W1 is transferred to the third transfer device based on information from various sensors, timers, etc. It is possible to calculate the time (conveyance time) from the time of loading to the time of conveyance to the cutting device. The transport time for each raw pipe W1 thus acquired is held as information related to transport related time (processing condition data) in the information database DB1 by the control device C1, and for any raw pipe W1 processed when necessary. However, the information can be extracted from the information database DB1.

<Cutting process>
As shown in FIGS. 4A and 4B, in the cutting step, the punched portion W0 at the front end portion of the raw pipe W1 and the end portion WE at the rear end portion are cut off, and the remaining middle portion is made the product length. It cuts so that it may be united and divided | segmented into several cylindrical body W2 .... For example, in the present embodiment, there are cases of division into three long cylindrical bodies W2 and cases of division into five short cylindrical bodies W2. The long cylindrical body W2 has a length of 250 mm, and the short cylindrical body W2 has a length of 150 mm. As will be described in detail later, in the present embodiment, the long cylindrical body W2 is referred to as type A, and the short cylindrical body W2 is referred to as type B. For reference, the long A-type cylindrical body W2 has a size of 200 mm before drawing, and the short B-type cylindrical body W2 has a size of 120 mm before drawing.

  In the cutting step, the raw pipe W1 is cut with a saw blade or the like. By simply measuring the pressure (cutting pressure) at the time of cutting, it is simply evaluated whether the load applied to the raw pipe material is good or not. Can.

  In the present embodiment, the control device C1 of the cutting device cuts the raw pipe W1 at a plurality of locations based on the cutting position information of the raw pipe W1 set in advance, and the cutting pressure at each cutting is It can be acquired. Furthermore, the control device C1 can acquire the identification number of the raw pipe W1 to be cut and processed, the cutting position and the like, and for each raw pipe W1 based on the information and the information on the cutting pressure. The information (cut pressure information for each position) of how much load (pressure) is applied to the cut position of the raw pipe W1 can be calculated, and this information is held in the information database DB1. Furthermore, the control device C1 can acquire the time (cutting time) required for the cutting process based on information from various sensors, a timer, and the like. When necessary, the cutting pressure information and the cutting time information for each part can be cut out from the information database DB1 for any of the processed raw pipes W1. In the present embodiment, the cutting pressure information and the drawing time information for each position of the raw pipe W1 constitute processing condition data.

  Further, in the present embodiment, the control device C1 determines, based on the cutting position information, information on which position of the raw pipe W1 before cutting corresponds to each cylindrical body (divided body) W2 ... after cutting (before and after cutting Corresponding position information) can be calculated. Further, information on which raw tube W1 before cutting the cylindrical body W2 after cutting is cut out is associated with the corresponding positional information before and after the cutting and is stored in the trace database DB2. Therefore, it becomes possible to cut out, from the trace database DB2, information on which portion of the raw pipe W1 before the cutting corresponds to which cylindrical body W2 before cutting, as required. There is. In the present embodiment, this information, that is, information on which part of the raw pipe W1 before the cutting corresponds to which the cylindrical body W2 corresponds to the data before and after division. Further, since the before and after division position data is acquired by the control device C1 of the cutting device, the control device C1 functions as a means for acquiring the before and after division position data.

  Further, as described above, since the trace database DB2 holds information (pre- and post-extraction position data) as to which position before extraction corresponds to each position of the raw pipe W1 after extraction, this pre- and post-extraction position Based on the data and the corresponding position information before and after cutting (pre and post position data), for any cylindrical body W2 cut, the cylindrical body W2 is in any part of the raw pipe W1 before drawing. It is possible to calculate and cut out the corresponding information.

<Fourth Transfer Step>
In the fourth transport step, the divided bodies W2 after being cut and processed are sequentially transported by the conveyor (the fourth transport device) to the cleaning device of the cleaning step.

  Further, the control device C1 in the fourth conveyance step can acquire the individual number of the divided body W2 to be conveyed in the same manner as described above, and the divided body W2 is transmitted to the fourth conveyance device based on information from various sensors, timers, etc. It is possible to calculate the time (conveying time) from the time of loading to the time of conveyance to the cleaning device. The conveyance time for each divided body W2 thus acquired is held as conveyance related time data (processing condition data) in the information database DB1 by the control device C1, and for any raw pipe W1 processed when necessary. Also, the information can be extracted from the information database DB1.

<Washing process>
As shown in FIGS. 4A and 4B, the cleaning process is performed to remove oil and the like remaining in the process of, for example, the previous process. The pallets 55 are arranged at predetermined intervals, and the pallets 55 are immersed in the cleaning liquid in the cleaning tank 5. At the time of this cleaning, the control device C1 (see FIG. 1) of the cleaning apparatus obtains information on the temperature (cleaning temperature) in the cleaning tank based on the information from the thermometer (temperature sensor) installed in the cleaning tank. As well as being able to, the time (washing time) required for the washing can be obtained. These pieces of information (processing condition data) are held in the information database DB1, and can be extracted from the information database DB1 when necessary.

<Fifth Transfer Process>
In the fifth transport step, the divided bodies W2 after being subjected to the cleaning processing are sequentially carried out by the conveyor (fifth transport device) up to a predetermined work collection point.

  Further, the control device C1 in the fifth conveyance step can acquire the individual number of the divided body W2 to be conveyed in the same manner as described above, and the divided body W2 is transmitted to the fifth conveyance device based on information from various sensors, timers, etc. It is possible to calculate the time (conveyance time) from the time of loading to the time of conveyance to a predetermined work collection point. The conveyance time for each divided body W2 thus acquired is held as conveyance related time data (processing condition data) in the information database DB1 by the control device C1, and for any raw pipe W1 processed when necessary. Also, the information can be extracted from the information database DB1.

<Product inspection>
A product inspection is performed on the divided body W2 transferred in the fifth transfer step. As shown in FIG. 1, in the present embodiment, the product inspection includes an automatic inspection in which the inspection is automatically performed and a visual inspection in which the operator manually inspects, and the automatic inspection basically includes all products. In contrast to visual inspection, visual inspection is only performed on some products by sampling.

  In the automatic inspection, an inspection (deformation inspection) of the deformation bending of the cylindrical body W2 and an inspection (appearance inspection) of the appearance quality of the cylinder W2 are mainly performed.

  In the deformation bending test, the displacement amount of the cylinder W2 in the radial direction is measured by a displacement sensor or the like while rotating the cylinder W2 about the axial center, and the deviation amount of the displacement of one rotation (360 degrees) Do. In addition, the deformation bending amount can be measured for each of a plurality of positions of the cylindrical body W2 by installing a plurality of displacement sensors for each of the positions to be measured.

  In the appearance quality inspection, illumination is applied to the outer peripheral surface while rotating the cylindrical body W2 about the axis, and the amount of reflected light is measured by a camera or the like to detect appearance abnormalities such as scratches, streaks, or discoloration. be able to. Further, the occurrence position of the image variation can be calculated from the image captured by the camera, and the occurrence position of the appearance abnormality can be accurately identified by integrating the image variation value for each occurrence position.

  In this embodiment, in the automatic inspection, when the bending abnormality (deformation) of the cylindrical body W2 or the discoloration or foreign matter adhesion is equal to or more than a predetermined reference, it is determined as a defect and the defective product is determined to be defective. For products, those that can be corrected can be corrected, those that can not be corrected, or they can be inspected in detail by visual inspection as needed. Then, they are sorted into a passable product and a reject product by comprehensive judgment.

<Method of identifying the cause of failure>
In the present embodiment, with respect to the work (cylindrical body W2) determined to be defective in the product inspection described above, the cause of the defect is identified. As a method of specifying the cause of failure, processing condition data related to the processing performed in each process is acquired for all the processed workpieces, and among the processing condition data, for the workpiece determined to be defective. Processing condition data is extracted, and the extracted data is collated with other processing condition data to find abnormal extracted data, and identify processing associated with abnormal data as a defect cause. For example, in the case where the workpiece is determined to be defective, and data indicating that the cleaning temperature in the cleaning step is too high is included, it is specified that the cleaning temperature is too high as a defect cause, and the pulling force is further extracted in the pulling step. Is too large, excessive pull-out force is identified as a defect cause.

  Further, in the present embodiment, the processing condition data includes data (transfer related time data) related to the transfer related time including the transfer time of the work in the transfer step. In the present embodiment, among the first to fifth plurality of transfer steps, any one transfer time is set in the transfer related time data, or the sum of any two or more transfer times is the transfer related time. Data can be set, or the sum (total) of all the transport times can be set as transport related time data. Furthermore, in the present embodiment, the sum of the transfer time of any one or more of the transfer steps of the first to fifth transfer steps and the processing time of any one or more of the production steps of the production steps (combination Can be set as transport related time data. A combination of these is optional, and appropriate transport related time data may be set for each production line.

  For example, in the product inspection, when the oil component in the drawing process adheres to the workpiece W1 and appearance abnormality is recognized, the time required from the drawing process to the cleaning process is one of the causes of the abnormality (defect). In the drawing process, the oil adhering to the workpiece W1 hardens before being washed in the washing process, and the oil solidified in the washing process can not be sufficiently removed. Therefore, the transfer related time data corresponding to the sum of the transfer time of the third transfer process, the processing time of the cutting process and the transfer time of the fourth transfer process is included in the process condition data, and the transfer of the work determined to be defective If the related time data is large (long) compared to the transfer related time data of other works, the cause of the failure is that the time from the start of the third transfer process to the end of the fourth transfer process is too long It can be identified as From the same idea, the sum of the transfer time of the third transfer step and the processing time of cutting process is used as transfer related time data, or the sum of the third and fourth transfer times is set as transfer related time data, or cutting time If the sum of the fourth transport time is stored as transport-related time data, it can be identified as the cause of the defect that the time required from the completion of the drawing process to the cleaning process is long.

  In addition, the total time required for production (lead time) may also cause an abnormality in the product. That is, if there is a defect such as equipment failure in any of the processes, the required time in the equipment failure process becomes longer and the lead time becomes longer. For this reason, the sum (lead time) of the transport time of the first to fifth transport processes and the processing time of the production process (heat treatment process, drawing process, cutting process and cleaning process) is the transport related time data (process condition data) In the case where it is set with reference to the transfer related time data of the workpiece determined to be defective and long, the defect cause can be identified as the lead time becoming too long. Conversely, if processing in the production process is insufficient, such as insufficient heating in the heat treatment process, insufficient processing in the drawing process, or insufficient cleaning in the cleaning process, the lead time may be shortened. In the case where the transfer related time data is short, it can be identified that the cause of the failure is that the lead time is too short.

  In addition, the total (total) of the transfer times in the first to fifth transfer steps may also cause an abnormality in the product. That is, when the next production process is performed before the state of the work is unstable and a defect occurs, for example, the cutting process is performed without sufficiently removing the processing heat in the drawing process, and the surface is broken due to the cutting defect. When an abnormality occurs, the first to fifth transport times, such as the third transport time, become short. Therefore, the sum of the first to fifth conveyance times is set as conveyance related time data (processing condition data), and the case is short with reference to the conveyance related time data of the work determined to be defective. Can be identified as the cause of the failure that the transport time is too short. Conversely, if the elapsed time until the next production process (downstream production process) is performed after the prescribed production process (upstream production process) is performed is too long, the work is scheduled Since it cools outside and there is a possibility that processing defects may occur in the downstream production process, it may be one of the causes of defects that the conveyance time of the defective work becomes too long.

  Specifically, in the present embodiment, the control device C1 for product inspection calculates and holds transfer related time data for all processed works based on the information held in the database DB1, and calculates The average value of the transfer related time data (transfer related time average value) is calculated and held. Then, the transfer related time data of the work determined to be defective is collated with the transfer related time average value, and when the transfer related time data of the defective work is abnormally larger or smaller than the transfer related time average value, the transfer The item related to the related time data is identified as the cause of the defect.

  In the present embodiment, the transfer related time data of the defective work is, for example, 1.1 times or more or 1.2 times or more to the average value of the transfer related time, as can be determined objectively from the later examples. It is determined that the size is too large, and it is determined that the size is smaller than 0.9 times or 0.8 times or less. Needless to say, the magnification serving as the determination criterion of the magnitude is not limited, and may be set appropriately.

  Here, in the present embodiment, the control device C1 for product inspection functions as a quality determination unit and a defect cause identification unit.

  As described above, according to the defect cause identification method of a work of the present embodiment, the transfer time of the transfer step before and after the production step is regarded as a candidate for the defect cause, and the defect cause is determined based on transfer related time data including the transfer time. Since the identification is made, it is possible to clearly identify the cause of failure related to the delivery time which could not be clarified conventionally. Therefore, the cause of the defect can be reliably removed to improve the manufacturing line, and the productivity can be improved and the cost can be reduced.

  Further, in the present embodiment, the above-described transfer related time data, that is, the processing conditions constituting the cause of the defect can be used as a determination standard when determining the quality of the work. That is, by acquiring transfer related time data of the work to be inspected for each work, and referring to the data, the work processed at a transfer related time equivalent to the defective work from among the works. And the selected work is determined to be defective. Specifically, the transfer related time is set as an inspection item when determining the quality of the work, and at the time of automatic inspection, the transfer related time data of the work to be inspected is longer or shorter than a predetermined reference range. In such a case, the work is automatically determined to be defective regardless of other inspections.

  Further, in the present embodiment, the process of dividing the work (element pipe W1) is associated, and each divided product is associated with each divided product unit area which is each section constituting each divided product among the work before divided. While being able to acquire position data before and after division, it is possible to acquire processing condition data in which processing conditions at the time when processing is performed in each process are obtained for each position of a work. Therefore, based on the position data before and after division, among the workpieces before division, divided product unit parts corresponding to defects for divided products judged to be defective by product inspection are selected, and data on the selected divided product unit parts and The processing condition data can be collated to extract the processing condition for each process with respect to the defective product unit part corresponding to the defect, and the cause of the defect can be identified based on the extracted data. As a result, it is possible to carry out a follow-up survey for each part in divided product units that constitute the work, not for the work unit before division, and to more accurately determine the cause of failure based on detailed information for each divided product unit. Can.

  Furthermore, in the present embodiment, a work shape deformation process for deforming a work such as drawing is included, and based on the deformation rate in the work shape deformation process, association between each position of the work before deformation and each work position after deformation It can be performed. Therefore, since it is possible to calculate each position of the workpiece before deformation from each position of the workpiece after deformation, it is possible to accurately calculate each divided product unit site corresponding to defects in the workpiece before deformation, and the defect cause is more accurate. Can be asked.

  In the above embodiment, although the transport time of the transport step or the combination of the transport time and the processing time of the production step is used as transport related time data, the present invention is not limited thereto. It is sufficient if the part includes the transfer time by any of the transfer steps. For example, a combination of any one or more of the transfer times of the plurality of transfer processes and the processing conditions of any one or more of the plurality of production processes may be set as the transfer related time data. It is possible. Specifically, the combination of the transfer time and the heating temperature of the heat treatment process is used as transfer related time data, or the combination of the transfer time and the maximum pressure or / and the minimum pressure of the drawing process is used as transfer related time data, Even if the combination of the transfer time and the maximum pressure or / and the minimum pressure of the cutting process is used as the transfer related time data, or the combination of the transfer time and the cleaning temperature in the cleaning process is set as the transfer related time data. good.

  <Example>

  Table 1 is a table showing processing conditions in each process for each part (each product unit part) corresponding to each cylindrical body W2 in the work W1.

  Numbers in parentheses at the left end of Table 1 are product unit numbers, and as shown in FIGS. 2A and 2B, product unit parts (division product units) constituting the product (cylindrical body) of the raw pipe W1 Site number). For example, “A01” and “B01” on the front side of hyphens such as “A01-1” and “B01-4” correspond to individual numbers of base pipes, and “1” and “4” on the rear side of hyphens It indicates the position. The raw pipe of the first letter "A" is a raw pipe of A type (type 1), and is later divided into three long divided bodies (cylindrical bodies) (see FIG. 4A). The raw pipe whose first letter is "B" is a raw pipe of B type (type 2) and is later divided into five divided bodies (cylindrical bodies) as shown in FIG. 2B (see FIG. 4B). In other words, the product unit number is also used as an individual number of a divided product (cylindrical body) after blank cutting. For example, as shown in FIG. 2A and FIG. 4A, the cylindrical body of “A01-1” is constituted by the first product unit portion “1” of the raw pipe of “A01”, and the cylindrical body of “A01-2” Is constituted by the second product unit part "2" of the raw pipe of "A01", and the cylindrical body of "A01-3" is the third product unit part "3" of the raw pipe of "A01" It will be configured. Similarly, as shown in FIGS. 2B and 4B, the cylindrical body of “B01-1” is constituted by the first product unit portion “1” of the raw pipe of “B01” as shown in FIG. 2B, The cylindrical body of "B01-2" is constituted by the second product unit part "2" of the raw pipe of "B01", and the cylindrical body of "B01-3" is the third of the raw pipe of "B01" And the cylindrical body of "B01-4" is constituted by the fourth product unit part "4" of the raw pipe of "B01", and the cylindrical body of "B01-5" And “5” of the fifth product unit part “5” of the raw pipe of “B01”. It goes without saying that the raw pipe mouthpiece processing parts “A01-0” and “B01-0” and the terminal parts “A01-E” and “B01-E” are cut off, so those parts are excluded in Table 1 .

  The item "conveyance (P1)" in Table 1 corresponds to the first conveyance step, and in this item, the conveyance time for each work is indicated.

  Further, as described above, the information on the conveyance condition (the conveyance time) is held in the information database DB1, and such information can extract only the necessary part when necessary. Further, information on work processing conditions and transport conditions in each of the following steps is the same, and is held in the information database DB1 so that it can be taken out as needed.

  The item “heat treatment (Q1)” corresponds to a heat treatment step, and in this item, the heat treatment temperature (heating temperature) and the heat treatment time (heating time) for each work are shown.

  The item "conveyance (P2)" corresponds to the second conveyance step, and in this item, the conveyance time for each work is indicated.

  The item "drawing process (Q2)" corresponds to the drawing process, and in this item, the presence or absence of chattering for each work, the maximum value "max" of the drawing force, and the minimum value "min" And the time required for drawing (processing time). Although the presence or absence of chattering is used as a criterion for determining whether the workpiece is good or bad, the presence or absence of chattering is not directly related to the understanding of the present invention. There is no mention.

  The item "conveyance (P3)" corresponds to the third conveyance step, and in this item, the conveyance time for each work is indicated.

  The item of "cutting (Q3)" corresponds to the cutting step, and in this item, the maximum value "max", the minimum value "min" and the presence or absence of occurrence of processing abnormality of the cutting pressure for each work And the time required for cutting (processing time). The processing abnormality is assumed to be a large load due to excessive cutting pressure if the maximum value of the cutting pressure is too large, but the occurrence of the processing abnormality is not directly related to the understanding of the present invention. Therefore, no particular mention is made in this specification.

  The item "conveying (P4)" corresponds to the fourth conveying step, and in this item, the conveying time for each work is indicated.

  The item of "cleaning (Q4)" corresponds to the cleaning processing step, and in this item, the cleaning temperature and the cleaning time for each work are shown.

  The item "conveying (P5)" corresponds to the fifth conveying step, and in this item, the conveying time for each work is indicated.

  Table 2A is a table showing transfer related time data (processing condition data) for each part (each product unit part) corresponding to each cylindrical body W2 in the work W1.

  In Table 2A, “P1” indicates the conveyance time in the first conveyance step (conveyance in Table 1), and “P2” to “P5” similarly indicate in the second to fifth conveyance steps. Indicates the transport time of Furthermore, in Table 2A, “(Q1)” indicates the processing time of the heat treatment step, and “Q2” to “Q4” similarly indicate the processing time of the drawing step, cutting step, and cleaning step. ing.

  Specifically, the transfer-related time data in the first row (T1) of Table 2A is the sum (P1 + Q1) of the first transfer time and the heat treatment time for each work, and in the second row (T2) The transfer related time data is a value (P1 + Q1 + P2) obtained by adding the second transfer time to the time of the T1 row. Likewise, in the third row (T3) to the eighth row (T8), the transport related time data is a value obtained by sequentially adding the subsequent transport time (P3 to P5) or the processing time (Q2 to Q4) to the time of the previous row. It is. Further, the transfer related time data in the ninth row (T9) of Table 2A is the added value (P3 + Q3) of the third transfer time and the cutting processing time for each work, and similarly, the tenth row (T10) to 12 rows The transport-related time data of the eye (T12) is a value obtained by sequentially adding the subsequent transport / processing times (P4, Q4, P5) to the time of the previous row. Moreover, the conveyance related time data of the last row (T13) of Table 2A is the sum total (P1 + P2 + P3 + P4 + P5) of the 1st-5th conveyance time for every workpiece | work.

  Table 2B shows the ratio (ratio) to the average value of transfer related time data for each work described in Table 1A. For example, “12 hours”, which is the value of transfer related time data (P1 + Q1) of the first column (T1) of the first row (A01-1) shown in Table 1A, has the transfer related time average as shown in Table 2B It shows that it is 0.9 times the value.

  The values shown in Tables 1A and 2B are automatically calculated based on the information of Table 1 held in the database DB1 by the control device C1 for product inspection.

  Table 3 is a table showing the inspection result of the automatic inspection by the inspection device and the inspection result (final visual judgment) of the visual inspection by the operator. The visual inspection is the position of the final inspection, and the visual inspection has priority over the automatic inspection and is highly reliable. The appearance (adhesion substance A) of the inspection item is to inspect whether or not the adhesion substance A such as an oil component is adhered. The appearance (adhesion B) is to check whether the adhesion B is attached or the like. The appearance (adhesion C) is to check whether or not the adhesion C is attached.

  As described above, in the actual inspection, in addition to the above-described appearance inspection, a large number of inspections such as other appearance inspections and bending inspections are also performed. However, in order to understand the present invention, There is no omission about the examination.

  First, in the appearance inspection of the attached matter A, it is determined as defective (NG) with respect to three workpieces “A51-2”, “A91-2”, and “A91-3”. When the cause was investigated by traceability to these three defective works, as shown in Table 2A and Table 2B, the total value of the third transport time and the cutting time (T9 = P3 + Q3) and the third and fourth transports It was found that the total value of time and cutting time (T10 = P3 + Q3 + P4) is 1.2 times larger than the average value and is larger. In addition, there is no data which has abnormality in common to the three defective works in the processing condition data other than the transfer related time data (T9, T10), and therefore the above time (T9 = P3 + Q3) (T10 = P3 + Q3 + P4) Can be estimated to be the cause of failure. Further investigation of the reason for the failure causes the time (T9, T10) to the washing step after the pulling step to be long, and the oil component deposited in the pulling step is solidified, and sufficient washing is performed in the washing step. It is thought that it could not be done.

  Although the work of “A51-1” and “A51-2” is the same material (work) before cutting, “A51-1” is determined to be non-defective and “A51-2” is determined to be defective. There is. It is considered that this is because the transport time (P4) after cutting is longer than “A51-1” for “A51-2”, and sufficient washing in the washing step can not be performed.

  In addition, in the automatic inspection of attached matter A, the work of “A91-2” is judged to be non-defective (OK), but it is considered that there is the same cause of failure as “A51-2” and “A91-3”. In consideration of the property, it was determined as poor (x) in the final visual judgment.

  Next, in the appearance inspection of the extraneous matter B, four works “A91-2”, “A91-3”, “A92-3”, and “A93-3” are determined to be defective. When this cause was investigated, it turned out that the lead time (T8 = P1-P5 + Q1-Q4) which is the total time required for production has become large with 1.1 times with respect to the average value. In addition, there is no data in the process data other than the transfer related time data (T8) that has abnormality in common with the four defective works, and thus the above time (T8) is long is the cause of the failure. It can be estimated. Furthermore, when investigating the reason which became the cause of failure, it took more time than the design lead time (T8) set in advance, so unexpected surface abnormality due to equipment failure etc. in each process It can be estimated that it occurred. In other words, as shown in Table 2A, when the lead time (T8) is 77 hours or more, it can be said that the possibility of being judged as defective is high.

  In the automatic inspection of the deposit B, although the work of "A92-3" is judged to be good, it is considered that there is the same cause of failure as "A91-2", "A91-3" and "A93-3". In consideration of safety, it was determined as poor (x) in the final visual judgment.

  Next, in the appearance inspection of the attached matter C, three works “A01-1”, “A10-3”, and “B01-4” are determined to be defective. When this cause was investigated, it turned out that the total conveyance time (T13 = P1-P5) of the 1st-5th conveyance process is small with 0.8 times with respect to an average value. In addition, there is no data in the process data other than the transfer related time data (T13) that has abnormality in common to the three defective works, and therefore the reason is that the above time (T13) is short. It can be estimated. Furthermore, if we investigate the reason that caused the defect, there is no waiting time (conveying time), the processing of the work advances one after another, and the next production can not be performed without processing heat in a given production process. Since the treatment was performed in the process, it can be estimated that the surface abnormality occurred due to the processing defect (insufficient treatment).

  In the automatic inspection of the deposit C, although the work of “A10-3” is judged as a good product, it is considered that there is the same defect cause as “A01-1” and “B01-4”, so the safety is taken into consideration. Then, it was determined as a defect (x) in the final visual judgment.

  As apparent from the above embodiments, it can be understood that the transfer related time including the transfer time in the transfer step becomes the cause of the defect of the work. Therefore, the transfer related time including the time of the transfer process before and after the production process is regarded as a candidate for the defect cause, and the transfer cause can not be clarified conventionally by specifying the cause of the defect based on the transfer related time data related to the transfer related time. It is possible to clearly identify the cause of failure of relevant time. Therefore, the cause of the defect can be reliably removed to improve the manufacturing line, and the productivity can be improved and the cost can be reduced.

  The method for identifying the cause of defects in a work according to the present invention can be applied to, for example, a production line in which a plurality of processes are sequentially performed on the work.

W1: Barrel (work)
W2: Cylindrical body (work)

Claims (10)

A plurality of production processes for processing the workpiece and a transport process for transporting the workpiece from a predetermined production process to the next production process, and inspection is performed on the workpiece obtained through each of the above-mentioned processes to determine its quality. In the method of identifying the cause of a defect of a work, the cause of the defect of the work determined to be a defect is identified.
Processing condition data on the processing performed in each step is acquired for each work, and processing condition data of each step for the work determined to be defective is extracted from the processing condition data, and the extracted data is extracted. While identifying the cause of failure based on
A method for identifying a defect cause of a workpiece, wherein the processing condition data includes transport related time data related to transport related time including a transport time of the workpiece in the transport step. A plurality of the transport steps are provided,
2. The method according to claim 1, wherein the sum of the transfer times in at least two or more transfer steps among the plurality of transfer steps is a transfer related time. A plurality of the transport steps are provided,
The method according to claim 1 or 2, wherein a total of all the transfer times in the transfer step is the transfer related time.   The time required for processing of the work in each production process is taken as the processing time, and at least one or more of the processing times are included in the transfer related time. How to identify the cause of defects in the work described in.   The production process includes at least one or more of a heat treatment process of performing heat treatment on a work, a drawing process of drawing, a cutting process of performing a cutting process, and a cleaning process of performing a cleaning process. The defective cause identification method of the workpiece | work of any one of claim | item 1 -4. The average value of the transfer related time of all the works to be processed is taken as the transfer related time average value,
The defect of the work according to any one of claims 1 to 5, wherein the transfer related time data of the work determined to be defective is collated with the transfer related time average value to identify the cause of the defect of the work. Cause identification method. A plurality of production processes for processing the workpiece, and a transport process for transporting the workpiece from a predetermined production process to the next production process, and the quality of the workpiece being judged whether the quality of the workpiece obtained through each process is good or not It is a judgment method, and
A defect cause is specified in advance by the defect cause specifying method of the work described in any one of claims 1 to 6, and the quality of the work is judged based on the defect cause. How to judge the quality of work.   Processing condition data concerning the processing carried out in each of the steps is acquired for each work, and by referring to the processing condition data, processing conditions constituting the cause of failure from among the works which have passed through each of the steps. The method according to claim 7, wherein a work on which the same processing has been performed is selected, and the selected work is determined to be defective. A plurality of production process units that process the workpiece, a transport unit that transports the workpiece from a predetermined production process unit to the next production process unit, and a quality determination unit that performs inspection on the produced workpiece to determine pass / fail; In a traceability system provided with defect cause identification means for identifying the cause of a defect of a work determined to be defect,
The defect cause specifying means acquires, for each work, processing condition data related to the process carried out in the production process unit and the conveying means, and the processing condition data of each process for the work determined to be defective among the processing condition data. Configured to extract processing condition data and identify the cause of failure based on the extracted data;
The traceability system according to claim 1, wherein the defect cause identification unit is configured to acquire, as the processing condition data, transfer related time data related to a transfer related time including a transfer time of the work by the transfer unit. A plurality of production process units for processing the work, transport means for transporting the work from a predetermined production process unit to the next production process unit, and quality determination means for performing inspection on the produced work to determine pass / fail In the included workpiece quality judgment system,
10. The system according to claim 9, wherein said pass / fail judgment unit is configured to judge the pass / fail of the work based on the cause of the failure specified in advance by the traceability system according to claim 9.

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