JP4665621B2 - Process improvement support system - Google Patents

Description

  The present invention relates to a technique for supporting process improvement of a production line composed of a plurality of processes, and more particularly to a technique effective for process improvement of a production line mainly composed of hands such as a cell production method.

  With the diversification of user needs, there is an urgent need to handle high-mix low-volume production, short delivery, and variable-volume production at the manufacturing site. Amid such environmental changes, many companies are shifting from belt conveyor type automated lines to hand-assembled lines such as cell production systems that are mainly hand-assembled for the purpose of improving productivity. The hand-assembled line is a production method in which multi-skilled workers share work flexibly in a small-scale line. As a result, it can be expected to improve work efficiency, reduce the defective rate, and realize small lot handling, in-process inventory reduction, production lead time reduction, and short delivery time.

  However, in contrast to an automated line that guarantees a substantially constant production lead time depending on the speed of the belt conveyor, the hand-assembled line is likely to vary in productivity. Unlike machines, there are inevitably variations in work time due to repeated, redo, rattling, meetings, breaks, etc., and fluctuations in workers (additional or reduced number of workers, skilled or unskilled workers) This is because mixing and replacement of persons) can easily affect the overall productivity.

  Therefore, for the introduction (start-up) of hand-assembled lines and efficient operation (mass production), it is important to accurately grasp the problems unique to hand-assemble and to make continuous efforts for process improvement.

  Several methods have been proposed for supporting the improvement of the automated line process.

  The process improvement support device of Patent Literature 1 analyzes a delay for each process by comparing a set schedule with an actual progress, and outputs a process element that is a delay factor, or delays for each process element. By displaying the time, estimating production delay and outputting the possibility of delay, the process improvement is supported. However, even if attention is paid only to the delay time for each process as in the same apparatus, it is not always possible to extract the correct delay factor (that is, the process to be improved). From the difference between the schedule and the actual results, it is not possible to determine whether the actual performance of the process was bad or simply the schedule was poor, and to grasp the actual effect of the delay of one process on the overall productivity. Because you can't. In addition, the apparatus performs delay prediction by modeling the difference between the actual result and the schedule with a normal distribution, but such a method cannot be applied to the above-described hand-assembled line. This is because the manual assembly line has many fluctuation factors such as the implementation of high-mix low-volume production and the replacement of workers, and stratified analysis until the normal distribution model can be applied is difficult.

The manufacturing process management method of Patent Document 2 uses the added value per time generated in the manufacturing process as an index for improving the process, and promotes the process improvement by notifying the responsible person and employees. However, this method merely displays the results of each manufacturing group on the computer and raises the awareness of competition and improvement among the groups. Discovery of specific problems (points to be improved) It does not support.
Japanese Patent Laid-Open No. 10-249683 JP 2002-229630 A

  The present invention has been made in view of the above circumstances, and its object is to provide a technology for supporting the implementation of efficient and effective improvement activities that contribute to the improvement of productivity of the entire production line. It is to provide.

  More specifically, the present invention appropriately extracts processes to be improved (required improvement processes) having a high probability of obtaining an effective improvement effect on the productivity of the entire production line prior to improvement activity planning. The purpose is to provide technology for realizing efficient and effective improvement activities.

  In order to achieve the above object, the present invention supports process improvement by the following means or processing.

  A first aspect of the present invention is a process improvement support system for supporting process improvement of a production line composed of a plurality of processes, and for each work flowing through the production line, the work time and production for each process required in each process The total process work time required from the start to the end is totaled, the result totaling means to accumulate as actual data together with the information about the work, and the range to be improved from the all process work time distribution of all the work are selected, the A correlation analysis means for extracting one or a plurality of processes having a strong correlation with the selected range as a process requiring improvement by referring to the work time distribution of each process included in the selected range; It is characterized by providing.

  With this configuration, an improvement process with a high probability of obtaining an effective improvement effect on the productivity of the entire production line is extracted based on the result data.

  Here, the result totaling means is measured by a process time measuring means for each process for measuring the work time for each process for each work, and a total process work time measuring means for measuring the total process work time for each work, It is preferable to have performance storage means for storing the work time for each process and the total process work time in association with information related to the workpiece.

  Further, the result totaling means has a reader for reading an ID tag attached to a workpiece, and reads the ID tag at an inlet and an outlet of the process to measure a work time for each process of the process, and the ID tag It is advisable to measure the working time of the entire process by reading at the entrance and exit of the production line. As a result, it is possible to easily perform work time measurement and result aggregation automatically or semi-automatically.

  Further, the process includes an actual work process in which an actual work is performed on the work, and a wait process in which the work is placed in a waiting state or a moving state before or after the actual work process. It is also preferable to include the actual work time from the work start to the work end in the actual work process and the residence time in the waiting process. As a result, the state in which the workpiece is in a waiting state or moving state before or after the actual work process can be handled as one process (waiting process), and the waiting process itself is the target of improvement process extraction. be able to.

It is also preferable that the result totaling means measures the total process work time and the actual work time of each actual work process, and calculates the residence time in each waiting process from the measured total process work time and the actual work time. That is, the time between the work end time of a certain actual work process and the work start time of the next actual work process is regarded as an inter-process residence time. The dwell time before the start of work in the first actual work process on the line may be calculated from the production start time (time at the line entrance) and the work start time in the first actual work process. The residence time after the start of the actual work process may be calculated from the work end time and the production end time (line exit time) of the last actual work process.

  The correlation analysis means includes a range setting means for selecting a range to be improved from all process work time distributions of all works, a work specifying means for specifying a work included in the selected range, and each process The work time analyzing means for obtaining the difference between the work time distribution for each process of the specific work specified by the work specifying means and the work time distribution for each process of all the works, and one or a plurality of processes having a large difference are required to be improved. It is preferable to have a required improvement process extraction means for extracting as As a result, it is possible to appropriately extract a process requiring improvement having a strong correlation with the range to be improved.

  The range setting means may select a range to be improved from a distribution range that is longer than the average portion and shorter than the maximum portion in the entire process work time distribution. Thereby, the process improvement which considered the characteristic of the hand-assembled line is attained.

  The correlation analysis means may display the entire process work time distribution, the range to be improved, and the work time distribution of each specific process for each process and the work time distribution of each work of each work on the display device. . As a result, it is possible to visually and intuitively understand the correlation of how much work time the specific work to be improved requires in each process.

  The correlation analysis means may change the display of the work time distribution for each process of the specific work for each process in real time when the range to be improved is changed. By looking at changes in the distribution of specific workpieces while changing the range in various ways, the correlation between each other can be understood more deeply, and an appropriate range can be set.

  The correlation analysis means may display the result data of the work included in the designated range on the display device when the entire process work time distribution or a partial range of the work time distribution for each process is designated by a user operation. The information on the workpiece includes a workpiece type and worker information, and the correlation analysis means designates at least one of the type, worker and working time when designated by a user operation. It is preferable to display the entire process work time distribution and the work time distribution of each process for the workpiece that meets the conditions. Thereby, work results can be analyzed in detail, and it can be used for examination of specific contents of process improvement.

  When the correlation analysis means fails to extract the required improvement process, it is preferable to change the range to be improved and re-extract the improvement required process using the changed range. Thereby, a more suitable improvement process can be found.

  It is also preferable that the process improvement support system further includes an improvement effect estimation unit that estimates an effect of improvement of a required process on the total process work time by simulation. This makes it possible to confirm in advance the improvement effect that the improvement of the required improvement process has on the productivity of the entire line, thereby facilitating the understanding of the correlation analysis result and the determination of whether or not to improve.

  The improvement effect estimation means sets an assumed improvement value representing a work time distribution for each process to be achieved after improvement of the process requiring improvement, and all process work after improvement based on the set assumed improvement value and the actual data It is preferable to simulate the time distribution and display the entire process work time distribution before and after the improvement.

It is also preferable that the process improvement system further includes a cost effect estimation unit that converts the improvement effect of the entire process work time estimated by the improvement effect estimation unit into a cost effect. Thereby, since the effect obtained by the improvement of the process requiring improvement can be grasped on a cost basis, the effect of the improvement and the investment cost can be easily compared, and the user's decision making can be supported.

  When there are a plurality of improvement plans, the cost effect estimation means may present the improvement plans ranked in descending order of cost effectiveness to the user.

  The cost effect estimation means may select improvement plans that have a cost effect equal to or greater than the investable cost, and rank those improvement plans in descending order of cost effectiveness and present them to the user. This makes it possible to extract an optimal improvement plan that can be improved within the investment cost.

  The present invention can be understood as a process improvement support system having at least a part of the above means. The present invention can also be understood as a process improvement support method including at least a part of the above processing, or a program for realizing the method. Each of the above means and processes can be combined with each other as much as possible to constitute the present invention.

  For example, according to a second aspect of the present invention, there is provided a process improvement support method for supporting process improvement of a production line composed of a plurality of processes, wherein the information processing apparatus is required for each work flowing through the production line in each process. The total work time for each process and the total process work time required from the start to the end of production are totaled, and the total results are stored in the storage device as performance data together with information on the work. It is necessary to improve one or a plurality of processes having a strong correlation with the selected range by selecting a range to be targeted and referring to a work time distribution of each work included in the selected range. It is characterized by extracting as an improvement process.

  According to a third aspect of the present invention, there is provided a program for causing an information processing apparatus to execute a process improvement support process for supporting process improvement of a production line composed of a plurality of processes. For each work flowing through the production line, a process for totaling the work time for each process required for each process and the total process work time required from the start to the end of production, and storing the total results as information on the work together with information on the work By referring to the process accumulated in the apparatus, the process of selecting the range to be improved from the entire process work time distribution of all workpieces, and the work time distribution for each process of the work included in the selected range And a process of extracting one or a plurality of processes having a strong correlation with the selected range as a process requiring improvement requiring improvement.

  According to the present invention, it is possible to appropriately extract an improvement target process (necessary improvement process) having a high probability of obtaining an effective improvement effect on the productivity of the entire production line. Therefore, efficient and effective improvement activities that contribute to the productivity improvement of the production line can be performed.

  First, the outline | summary of the process improvement assistance system which concerns on embodiment of this invention is demonstrated.

  The process improvement support system according to the present embodiment is roughly configured by four functions of “results aggregation”, “correlation analysis”, “improvement effect estimation”, and “cost effect estimation”. Note that these functions are realized by a computer program, and each function can be provided as a separate module. In other words, the process improvement support system has a structure in which only results are accumulated, a structure in which results are aggregated + correlation analysis, a structure in which results are aggregated + correlation analysis + improvement effect estimation, and results aggregation + correlation analysis + improvement effect estimation + cost effect estimation. Any of the configurations can be adopted.

(1) Results tabulation The results tabulation function is the work time for each process required for each process and the total process work time required from the start to the end of production (also referred to as production lead time). Is accumulated in the storage device as performance data together with information on the workpiece. The accumulated result data is used as a material for grasping production results and determining necessity of process improvement, and is used for processing such as correlation analysis described below.

(2) Correlation analysis The correlation analysis function is a function that extracts a process that requires improvement (referred to as a process that requires improvement) based on actual data.

  In the process improvement of the conventional automated line, the approach of comparing the results of each process and selecting a process with a poor performance (such as a process with a large production delay with respect to the schedule) as a process requiring improvement is common. However, as shown in Fig. 1, because of the large variation in work time in the hand-assembled line such as the cell production method, where the work time results by process are, there is a problem, and which process should be improved It is difficult to grasp whether the productivity of the entire line can be increased. Therefore, the conventional approach has not been able to accurately find the location of the problem.

  Therefore, in the correlation analysis function, the range to be improved is selected from the distribution of all process work times of all workpieces, and the selection is performed by referring to the work time distribution for each process of the workpieces included in the selected range. The method of extracting a process having a strong correlation in the range as a process requiring improvement is used. In other words, an approach is adopted in which a problem is grasped from the overall performance of the production line, and then a main factor of the problem is searched from a correlation with the performance by process. With such an approach, it is possible to appropriately extract a process requiring improvement that can provide an effective improvement effect on the productivity of the entire production line. In addition, as a process requiring improvement, you may extract only one process with the strongest correlation, and you may extract a some process in an order from a strong correlation.

  Furthermore, the correlation analysis function pays attention to a part slightly worse than the average of actual results, instead of paying attention to a part greatly deviating from the management reference value when selecting a range to be improved from the overall results ( The management reference value is a reference value used to determine whether normal production or abnormal production in daily work at the production site. For example, a reference lead time for determining whether production is delayed or not. Sure.)

  As shown in the actual data example in FIG. 2 (histogram of production lead time), in the automated line, the production lead time is kept almost constant, and normal production and production delay are clearly separated. Therefore, in the case of an automated line, a certain improvement effect can be expected by taking measures only by paying attention only to values (exceptional factors such as equipment failure or stoppage) that deviate greatly from the management reference value.

  However, in the case of hand-assembled lines, parts that deviate significantly from the control standard values may be caused by factors unrelated to the process design (for example, the worker has left the workplace due to breaks, toilets, calls, etc.) However, even if some improvement measures are taken in that area, a great effect cannot be expected. Rather, the portion with a slightly worse value than the actual average is more likely to be caused by variations in the work of the person, such as difficulty in work or frequent rework, and the occurrence frequency is also high.

  In order to take into account the unique characteristics of such hand-assembled lines, the correlation analysis function of the present embodiment is longer than the average part of the total process work time distribution and has a maximum part (much different from the control reference value). A range to be improved is selected from a distribution range shorter than (part). Hereinafter, this part is referred to as “appropriate improvement range”.

(3) Improvement effect estimation Even if the required improvement process can be extracted by the above-described correlation analysis, whether or not the analysis result is correct just by presenting the analysis result and actually improving the improvement required process It may be difficult for the user to determine whether to do this. In addition, when a plurality of processes are presented as candidates for the process requiring improvement, a material for determining which improvement plan should be adopted is required.

  Therefore, the improvement effect estimation function estimates the effect of improvement of the required improvement process on the production lead time (all process work time) of the entire production line, and presents the estimation result to the user in an easily understandable form. As a result, it is possible to easily understand the analysis results and determine whether or not to make improvements.

(4) Estimating the cost effectiveness Even if the production lead time after improvement becomes clear by estimating the improvement effect, if it is not clear whether the improvement implementation is worth the investment cost, make a final decision on the improvement implementation. I can't. A major decisive factor when a user decides to implement improvement for a process is a cost effect obtained by making an improvement (how much cost effect can be obtained by which improvement measure). In addition, when it is necessary to obtain a payment for improvement implementation from the supervisor, it is easy to make a settlement judgment by presenting a specific cost effect together with a proposal for improvement.

  Therefore, the cost effect estimation function converts the improvement effect of the production lead time (total process work time) into the cost effect and presents it to the user. This makes it possible to compare the effect obtained by the improvement implementation with the investment cost, and to support the user's decision making (selection of process to be improved, improvement plan, determination of improvement implementation).

  As described above, in the process improvement support system of the present embodiment, an appropriate improvement point (necessary improvement process) is extracted from the overall results, and if necessary, the improvement effect is estimated or converted into cost. By presenting it to the user, it is possible to work on effective and efficient process improvement.

  Now, a specific configuration example of the process improvement support system will be described in detail with reference to the drawings.

<Configuration of process improvement support system>
FIG. 3 shows the overall configuration of the process improvement support system. The process improvement support system is a computer system that supports process improvement of a production line composed of a plurality of processes (FIG. 3 shows an example of three processes A, B, and C). A computer 10, an input device 11 composed of a keyboard and a mouse, a display device 12 composed of a liquid crystal display, a storage device 13 composed of a hard disk, etc., and a reader 14 installed in each process. .

  The computer 10 can be configured using a general-purpose personal computer or workstation provided with an arithmetic processing unit (CPU), a main storage device (memory), an auxiliary storage device (hard disk), and the like. The various functions of the process improvement support system are realized by a program stored in the auxiliary storage device being read into the main storage device and executed by the arithmetic processing unit.

  The reader 14 is a device that reads identification information from an ID tag 22 attached to a workpiece (processed product) 20 flowing through a production line. The reader 14 is arranged at the entrance and exit of each process, and reads the identification information at the start and end of work in each process. The identification information read by the reader 14 is immediately sent to the computer 10. In addition, the reader | leader 14 may be made to share in the place where there is no residence between processes like between the process B and the process C.

  This identification information is information for identifying unique information (manufacturing number, etc.) and model of the workpiece. The identification information itself may include the workpiece unique information and model, or the identification information is associated with the unique information and model in another database, and the workpiece information can be obtained from the identification information by referring to the database. May be obtained.

  A means for realizing the ID tag 22 and the reader 14 is not limited, but a mechanism capable of reading information without contact is preferable. For example, it may be configured by an RFID tag and its reader, a barcode and barcode reader, a two-dimensional code and a two-dimensional code reader, and the like. If the reader 14 is configured to be movable and the reading operation at the start and end of work is performed by the operator's reader operation, it is possible to make one reader in one process or one reader in a plurality of processes. It is.

<Achievement function>
FIG. 4 shows functional blocks related to the result totaling function of the process improvement support system. The result totaling function includes a work identification function 15, a process work time measurement function 16 for each process, an all process work time measurement function 17, a result DB (database) 18, and a result display function 19.

  During operation of the production line, identification information of individual workpieces 21 flowing through the line is read by the reader 14 and sequentially input to the computer 10. In the computer 10, the work identification function 15 identifies the unique information and model of the work 21 based on the identification information, and passes the information to the process time measurement function 16 for each process and the work time measurement function 17 for all processes.

  The work time measuring function 16 for each process temporarily uses the time when the identification information is read at the entrance of the process A as the work start time and the time when the identification information is read at the exit of the process A as the work end time. It memorize | stores and calculates the work time for every process required by the process A from those differences. The work start time, work end time, and work time for each process are recorded in the result DB 18 together with the unique information and model of the work. This process is executed in the same way for the process B and the process C.

  The total process work time measuring function 17 uses the time when the identification information is read at the entrance of the process A, which is the first process, as the production start time, and the time when the identification information is read at the exit of the process C, which is the final process. Is temporarily stored as the production end time, and the total process work time (production lead time) is calculated from the difference therebetween. The production start time, production end time, and total process work time are recorded in the performance DB 18 together with the unique information and model of the workpiece.

  Here, not only the process A, process B, and process C, which are actual work processes, but also before the process A starts, the process A ends, the process B starts, the process B ends, and the process C starts. In addition, the state where the workpiece is waiting for the work after the completion of the work in the process C or the movement of the work place may be regarded as one process. A process in which the workpiece is placed in a waiting state or a moving state in this way is called a “waiting process”. As shown in FIG. 22, in the line of the present embodiment, there are four waiting processes (that is, waiting process before start, waiting process A between processes, waiting process B between processes, waiting process after completion). Here, the time from the start of work to the end of work in the actual work process is called “actual work time”, and the waiting time in each waiting process is called “dwell time”. The residence time before the start can be calculated from the production start time and the work start time of the process A. The inter-process residence time A can be calculated from the work end time of the process A and the work start time of the process B. Similarly, the inter-process residence time B can be calculated from the work end time and the work start time of the two actual work processes. The residence time after completion can be calculated from the work end time and the production end time of the process C. In this way, the waiting process itself is regarded as one process in the same row as the actual work process, so that the waiting process itself can be a target of the results tabulation and the improvement process extraction.

  With the above processing, the work time for each process required for each process and the total process work time required from the start to the end of production are easily measured for each work flowing through the production line. The result data is accumulated in the result DB (result storage means) 18. The actual data includes information related to the workpiece (work specific information, model, information on the worker who performed the work) and measurement results (start / end time and actual work time for each process, production start / end time and all Process working time and dwell time of each waiting process).

  The result display function 19 can output the result data accumulated in the result DB 18 to the display device 12 in a user-friendly format such as a table, a histogram, a bar graph, and a pie chart. FIG. 5 shows a display example of performance data, in which a histogram of all process work times (horizontal axis: work time, vertical axis: number of times) is presented. The user can grasp the production results and the deviation from the schedule by looking at such result data, and can determine whether or not the process needs to be improved.

  Another display example of performance data is shown in FIGS. FIG. 23A is a pie chart showing the ratio of the actual work time and the residence time in the whole process work time for one or a plurality of workpieces. FIG. 23 (b) individually shows the breakdown of the work time (actual work time / dwell time) of each process (actual work process / waiting process) in all process work times for one or a plurality of workpieces. Is. At this time, as the work time for each process, both the actual work time and the stay time may be displayed, or only the actual work time and only the stay time may be displayed. For example, FIG. 24 is an example in which the breakdown of the residence time is displayed as a bar graph. Further, it is also preferable that a list of work times (retention times) required for each specific process (selected work) in each step can be displayed. FIG. 25 shows an example in which only the work time (stay time) of a specific workpiece is displayed in different colors in the work time distribution (histogram) for each process. Furthermore, it may be possible to display a list of work times (retention times) related to all works handled by a specific worker. In FIG. 26, in the work time distribution (histogram) for each process of each process, only the work time (staying time) of the work handled by the specific worker is displayed in different colors. Thereby, for example, it can be used for grasping the weakness of each worker and the process in which delay is likely to occur.

<Correlation analysis function>
FIG. 6 shows functional blocks related to the correlation analysis function of the process improvement support system. As described above, the correlation analysis function is a function that is responsible for selecting an appropriate improvement range from the entire production line results and extracting a process having a strong correlation with the range as a required improvement process. A specific function 31, a work time analysis function 32, a required improvement process extraction function 33, a required improvement process presentation function 34, and a range setting support function 35 are configured.

  The flow of the correlation analysis process will be described along the flowchart of FIG.

  When the correlation analysis function is activated, first, result data is read from the result DB 18 (step S100). Here, all the result data accumulated in the result DB 18 may be read, or a part of the result data may be read by designating a period and other reading conditions.

Next, an appropriate range for improvement is set by the range setting function 30 (step S101). The improvement appropriate range may be selected by a user operation or may be automatically selected. In the case of a user operation, the range setting function 30 displays a histogram of all process work time distributions of all workpieces as shown in FIG. 8, and allows the input device 11 (mouse, keyboard, touch panel, etc.) to select a range. At this time, the corresponding range on the histogram may be directly selected, or a range based on the management reference value (for example, management reference value ± 5%, management reference value + 5%, etc.) may be input. . On the other hand, in the case of automatic selection, the range setting function 30 selects a predetermined range (for example, management reference value ± 5%, management reference value + 5%, etc.) as an appropriate improvement range based on the management reference value, A predetermined range may be selected as an appropriate improvement range based on an average value between the average value and the maximum value. Alternatively, the automatically selected range may be presented to the user, and the user may be allowed to determine whether or not the range is selected, or the user may perform range adjustment. In any of the selection methods, as shown in FIG. 8, an appropriate improvement range is selected from a distribution range that is longer than the average portion (near the average value of the work time) and shorter than the maximum portion (near the maximum value). Is preferably selected. In order not to select the average portion and the maximum value portion, a restriction may be provided to disable selection of those portions, or guidance may be output.

  Next, the work specifying function 31 specifies a work included in the appropriate improvement range (step S102). Specifically, the results data of individual workpieces are examined to find out what is within the appropriate improvement range for all process work times. The workpiece specified here is called a specific workpiece.

  When the specific workpiece is found, as shown in FIG. 9, the work time distribution for each process along with the entire process work time distribution is displayed in a histogram, and the improvement appropriate range and the work time distribution for each process of the specific work are superimposed on the histogram. May be displayed in different colors (hereinafter, the work time distribution for each process of all workpieces is referred to as “all work distribution”, and the work time distribution of each specific work for each process is referred to as “specific work distribution”). As a result, it is possible to visually and intuitively grasp the correlation of how much work time the specific workpiece selected as the appropriate improvement range requires in each process.

  Further, in the display screen of FIG. 9, the appropriate improvement range can be changed by a user operation such as mouse click or drag, and the display of the specific work distribution is changed (updated) in real time according to the change. Also good. By looking at changes in the distribution of specific workpieces while changing the improvement appropriate range in various ways, the correlation between each other can be understood more deeply, and an appropriate improvement appropriate range can be set by user judgment.

  Furthermore, as shown in FIG. 10, when a range of the entire process work time distribution or a part of the work time distribution for each process is designated by the user operation, the result data of the workpieces included in the designated range is displayed. May be. FIG. 10 shows an example in which information such as workpiece specific information, type, start / end time, and work time is displayed in a list. Furthermore, the user may be allowed to input conditions such as model, worker, work time zone, etc., find a work that matches the specified conditions, and display only the work time distribution related to the work. As a result, work results can be analyzed in detail, for example, by identifying models with high workloads or by grasping the proficiency level of each worker, it is useful for examining the specific contents of process improvements. be able to.

  Next, the work time analysis function 32 compares the specific work distribution with the entire work distribution for each process, and analyzes the difference between the two distributions (step S103).

  The distribution difference is obtained by quantifying the difference in profile between the specific work distribution and the whole work distribution. For example, the distribution average, standard deviation, variance, maximum value, and minimum value (including combinations thereof) are also included. A statistical difference such as can be used. If the difference between the two distributions is small (that is, both distributions have similar profiles), it can be considered that there is no problem in the work of the specific workpiece in the process. On the contrary, it can be considered that there is some problem in the work of the specific workpiece as the difference between the two distributions is larger.

Specifically, as the difference in distribution, the difference between the average values of the specific work distribution and the entire work distribution (however, only when the specific work distribution has a larger average value) or the difference in standard deviation (or variance) is used. Good. The difference between the average values is an index indicating how much the specific workpiece distribution is distributed with respect to the entire workpiece distribution (see FIG. 11A), and the difference in standard deviation (or variance) is
This is an index representing how much the specific work distribution is distributed at a different ratio from the whole work distribution (see FIG. 11B). In this embodiment, the work time analysis function 32 calculates an average value, a difference between the average values, and a standard deviation for the specific work distribution and the entire work distribution in each process.

  Next, the required improvement process extraction function 33 extracts one or more required improvement processes having a large distribution difference (step S104). When the number of extraction is one, the required improvement process extraction function 33 extracts the process having the largest difference between the average values of the specific work distribution and the entire work distribution as the improvement required process. When there are a plurality of extractions, a predetermined number of improvement-needed steps are selected in order from the step with the largest difference in average value. If the difference between the average values matches, a process with a small standard deviation of the specific work distribution may be preferentially selected.

  Subsequently, the required improvement process extraction function 33 checks whether or not the difference between the average values of the extracted improvement required processes exceeds a threshold value. This threshold value is a reference value for determining whether or not there is a significant difference between the specific workpiece distribution and the entire workpiece distribution that should be extracted as a required improvement process, and is set in the system in advance. Alternatively, it is set appropriately by the user. When the difference between the average values of the extracted improvement required processes is equal to or less than the threshold value, the process is excluded from the improvement required processes or set as a temporary improvement required process.

  Even when the standard deviation difference is used as the distribution difference, the required improvement process can be extracted by the same method.

  Next, the improvement required process presentation function 34 presents the extracted improvement required process to the user (step S105). When there are a plurality of improvement-needed processes, the list is displayed in descending order of distribution difference (in order of necessity of improvement). In addition, the provisional improvement required process may be made to be provisional (the necessity for improvement is small) by color coding or the like. Thereby, the user can easily grasp from which process the effect is large.

  In the above processing, when an appropriate improvement process cannot be extracted (for example, when there is no process exceeding the threshold value or when the predetermined number is not reached, the user does not indicate the required improvement process. In the case where it is determined that the re-extraction process of the improvement-necessary process is executed as follows (step S106; No).

  First, the range setting support function 35 changes the appropriate improvement range. For example, a new improvement appropriate range is set by reducing / enlarging / moving the original improvement appropriate range by ± several percent. Then, using this new appropriate range for improvement, an attempt is made to extract a process requiring improvement by the same method as described above (step S107). If the improvement-necessary process can be extracted (step S108; Yes), the improvement-necessary process is presented to the user in the same manner as in step S105 (step S109). By such a process, a more appropriate improvement process can be found.

  When reextraction of the process requiring improvement fails (step S108; No), or when the user determines that the reextraction result is not the process requiring improvement (step S110; No), the improvement appropriate range is re-established for the user. An inquiry is made as to whether or not to set (step S111). If Yes, range setting processing by a user operation is executed (step S101). As a result, it is possible to assist the user in narrowing down the necessary improvement process.

  Through the correlation analysis process described above, a process with a high probability of improvement (a process requiring improvement) from which an effective improvement effect is obtained on the productivity of the entire production line is appropriately extracted.

<Improvement effect estimation function>
FIG. 12 shows functional blocks related to the improvement effect estimation function of the process improvement support system. As described above, the improvement effect estimation function is a function for estimating the effect that the improvement of the required improvement process has on the entire process work time, and includes an assumed improvement value setting function 40, a simulation function 41, and an improvement effect display function 42. Is done.

  The flow of the improvement effect estimation process will be described along the flowchart of FIG.

  The improvement effect estimation function first receives the improvement required process from the correlation analysis function and reads the result data from the result DB 18 (step S200).

  Next, the assumed improvement value setting function 40 sets an assumed improvement value for the process requiring improvement (step S201). The assumed improvement value is a target value for improvement and represents a work time distribution to be achieved after improvement. Specifically, it is indicated by any one of an average value, variance, maximum value, minimum value, or a combination of work times in a process requiring improvement after improvement. Further, the kurtosis and skewness of the work time distribution may be considered as the assumed improvement value. The maximum value (minimum value) is a boundary value of work time in normal work, and it is assumed that there is no work time larger (smaller) than this value.

  The assumed improvement value may be set by a user operation, or may be automatically set by the system. In the case of a user operation, the assumed improvement value setting function 40 presents to the user the work time distribution before improvement of the process requiring improvement and its average, variance, maximum value, and minimum value, and prompts the user to input the assumed improvement value ( (See FIG. 14). The user operates the input device 11 to input a numerical value directly or input an assumed improvement value by modifying the graph of the work time distribution. In the case of automatic setting, the assumed improvement value setting function 40 uses an assumed improvement value set in the system in advance, or makes a predetermined correction to the average, variance, maximum value, minimum value, etc. before improvement of the process requiring improvement. A value obtained by applying (for example, reducing the value by several percent to several tens percent) is assumed to be an assumed improvement value.

  Next, the simulation function 41 receives the actual data and the estimated improvement value of the process requiring improvement as input, and obtains the entire process work time distribution of the production line assumed after the improvement by simulation (step S202).

  In the hand-assembled line, different types of workpieces are mixed, and humans perform work, resulting in variations in work time. For this reason, the working time of each process is not constant, and a state other than the actual work such as the stay of the work or the waiting state of the work occurs irregularly. When the work time of the improvement-necessary process changes to a state assuming improvement, the stagnation of the workpiece, the waiting state for the work, and the like also change irregularly. Therefore, the total process work time (production lead time) of the entire line cannot be accurately calculated by simply adding / subtracting the assumed data after the improvement of the process requiring improvement to the actual data of other processes. Therefore, the simulation function 41 predicts the occurrence of stagnation between the processes and the waiting state based on the actual data and the estimated improvement value of the process requiring improvement, and comprehensively considers them, and the total process work time after the improvement. Ask for. As the simulation function 41, a known production simulation tool can be used (for example, eM-Plant manufactured by Nippon Technomatics Co., Ltd.).

  Next, the improvement effect display function 42 displays the simulation result (step S203). At this time, as shown in FIG. 15, the post-improvement all-process work time distribution assuming post-improvement of the process requiring improvement may be superimposed on the pre-improvement all-process work time distribution. This facilitates comparison of production lead times before and after improvement.

  According to the improvement effect estimation process described above, it is possible to confirm in advance in advance an easy-to-understand understanding of the improvement effect that the improvement of the required improvement process has on the production lead time of the entire line. Becomes easier.

  In this embodiment, the improvement effect is estimated on the assumption that one improvement process is improved. However, when a plurality of improvement processes are extracted in the correlation analysis, each improvement process is required. It is also preferable to estimate the improvement effect individually for each of them so that the magnitudes of the improvement effects of the plurality of improvement plans can be compared, or to estimate the improvement effect when a plurality of improvement steps are improved simultaneously.

<Cost-effect estimation function>
FIG. 16 shows functional blocks related to the cost effectiveness estimation function of the process improvement support system. As described above, the cost effect estimation function is a function that converts the improvement effect of the entire process work time estimated by the improvement effect estimation process into a cost effect, and includes a cost conversion function 50, a required improvement process selection function 51, and a cost. The effect display function 52 is comprised.

  The flow of the cost effect estimation process will be described along the flowchart of FIG.

  The cost effect estimation function first receives the estimation result (all process work time distribution after improvement) from the improvement effect estimation function and reads the result data (all process work time distribution before improvement) from the result DB 18 (step S300). .

  Next, the cost effect estimation function reads the production line hour unit price from the storage device 13 (step S301). The production line unit price is a cost per unit time required for the operation of the production line, and is an index used to convert the improvement effect (shortening effect) of the work time into the cost effect. The production line hour unit price may be calculated from the total cost for a certain period in the past (for example, one month). The breakdown of the total cost includes, for example, labor costs, equipment costs, electricity costs, production line installation space costs, inventory space costs, and the like.

  Next, the cost conversion function 50 converts the improvement effect of the work time into the cost effect based on the entire process work time distribution before and after the improvement and the production line time unit price (step S302). In addition, when the improvement effect about a several improvement plan (required improvement process) is estimated in the improvement effect estimation process, the cost conversion function 50 performs cost conversion about each improvement plan.

  FIG. 18 shows the basic concept of the cost conversion process. FIG. 18 shows the entire process work time distribution before improvement (broken line) based on the actual data and the all process work time distribution after improvement (solid line) based on the improvement effect estimation. In the figure, Tmin and Tmax indicate the minimum and maximum values of the total process work time distribution before improvement, respectively, and T'min and T'max indicate the minimum and maximum values of the total process work time distribution after improvement, respectively. ing. Moreover, Tcross has shown the position where all process operation time distribution before and behind improvement crosses.

here,
Area S = (area of all process work time distribution before improvement) − (area of all process work time distribution after improvement) (however, Tcross ≦ all process work time ≦ Tmax)
Area S ′ = (area of all process work time distribution after improvement) − (area of all process work time distribution before improvement) (provided that T′min ≦ all process work time distribution <Tcross)
Then, the cost conversion function 50 calculates the difference between the cost conversion value V of the area S and the cost conversion value V ′ of the area S ′ as the cost effect (V−V ′) achieved by the process improvement.

FIG. 19 shows a specific example of a cost effect calculation method. The entire process work time distribution is divided into sections each having a certain time width (for example, 5 minutes). The work time at the center (or average) of each section is tn, the number of all process work time distributions before improvement (number of production) is Nn, and the number of work time distributions after improvement (number of production) is N'n. (Where n = 1, 2, 3,..., M
ax), the cost effect is calculated by the following equation.

FIG. 20 shows another specific example of the cost effect calculation method. When the work time before the work n is improved is tn and the work time after the work n is improved is t′n (where n = 1, 2, 3,..., Max), the cost effect is Calculated.

  When the cost effect is calculated for a plurality of improvement plans (step S303; Yes), the improvement process selection function 51 ranks the improvement plans in descending order of cost effect (step S304). If the setting is such that the improvement plan is automatically determined by the system (step S305; Yes), the improvement process selection function 51 requires the improvement plan set in advance from the ranking top improvement plan or the higher ranking. A cost-effective improvement process is selected (step S306). Then, the cost effect display function 52 displays the process name of the process requiring improvement and the cost effect as an improvement plan (step S307). On the other hand, if the setting is such that the user determines the improvement plan (step S305; No), the improvement-necessary process selection function 51 displays a list of improvement plans in descending order of ranking (step S308).

  Thus, according to the cost effect estimation function, it is possible to grasp the effect obtained by the improvement of the process requiring improvement on a cost basis, so it becomes easy to compare the effect of the improvement implementation with the investment cost, and the intention of the user. Supports decisions (selection, refinement, and final decision on improvement implementation), enabling efficient and effective improvement efforts.

  In step S306, an improvement plan may be selected in consideration of a budget (investable cost) that can be invested for improvement. That is, improvement plans that are cost-effective beyond the investable cost are selected and ranked in the order of cost effectiveness. In this way, by using the investable cost as a parameter for selecting an improvement plan, it is possible to extract an optimal improvement plan (necessary improvement process) that can be improved within the investment cost. The investable cost may be set in advance in the system, or may be input by the user each time.

<Management standard value update function>
The process improvement support system of this embodiment has a management reference value update function as an additional function.

  As shown in FIG. 21 (a), even if the management reference value is set to an appropriate value before the process improvement, if the entire process work time is shortened as shown in FIG. 21 (b) by the process improvement. The management reference value becomes a loose value (with a margin). If such an inappropriate management reference value is set, it is not preferable because there is a possibility that the worker's motivation will be lowered and the productivity will be lowered. Therefore, the management reference value update function determines whether the management reference value is good (appropriate / inappropriate) based on changes in the work time distribution of all processes before and after improvement, and updates the management reference value to an appropriate value as necessary. (See FIG. 21 (c)).

The quality judgment of the management reference value may be performed as follows. For example, it is assumed that a state where the portion exceeding the control reference value (shaded portion in FIG. 21A) is 30 ± 5% of the entire process work time distribution is appropriate. This appropriate value is preset in the system by the user. The management reference value update function acquires the improved all process work time distribution estimated by the improvement effect estimating means, and the ratio of the portion exceeding the control reference value in the improved all process work time distribution and the above appropriate value Compare If the ratio of the portion exceeding the management reference value is out of the appropriate value, it is determined that the current management reference value is inappropriate.

  Even if an appropriate value for the management reference value is not set in the system in advance, the proportion of the portion exceeding the management reference value after the improvement is greater than or equal to the predetermined value compared to the proportion of the portion exceeding the management reference value before the improvement. When it is small, it can be determined that the current management reference value is inappropriate.

  If the management reference value is determined to be inappropriate by the above processing, the management reference value is updated by a user operation or automatic setting. In the case of a user operation, the management reference value update function displays the entire process work time distribution before and after the improvement and the current management reference value on the screen as shown in FIG. The user inputs a new management reference value by operating the input device 11 to directly input a numerical value or by dragging and moving the management reference value on the graph with a mouse. However, since the management reference value is meaningless unless it is set in a feasible range, it is preferable that the system side regulates so that the management reference value cannot be set in a range that is considered impossible. In the case of automatic setting, the management reference value update function calculates a new management reference value based on an appropriate value preset in the system. In addition to the case where the appropriate value is specified by the ratio of the portion exceeding the control reference value as described above, the appropriate value is specified by the ratio (standard deviation, variance, etc.) from the average value of the entire process work time distribution. There is also.

  By updating the management reference value to an appropriate value by the processing described above, the operator's motivation can be maintained, and a reduction in productivity can be prevented in advance.

The figure which shows the dispersion | variation in the working time in each process of a hand-assembled line. The figure which shows the histogram of the production lead time of an automation line and a hand-assembled line. The figure which shows the whole structure of a process improvement support system. The figure which shows the functional block which concerns on the performance totaling function of a process improvement support system. The figure which shows the example of a display of performance data. The figure which shows the functional block which concerns on the correlation analysis function of a process improvement support system. The flowchart which shows the flow of a correlation analysis process. The figure which shows the example of a display for setting an improvement suitable range. The figure which shows the example of a display of an improvement appropriate range and specific work distribution. The figure explaining the improvement suitable range and the display function of specific work distribution. The figure explaining the difference of specific work distribution and all work distribution. The figure which shows the functional block which concerns on the improvement effect estimation function of a process improvement support system. The flowchart which shows the flow of an improvement effect estimation process. The figure explaining the setting process of an assumption improvement value. The figure which shows the example of a display of all process work time distribution before and behind improvement. The figure which shows the functional block which concerns on the cost effect estimation function of a process improvement support system. The flowchart which shows the flow of a cost effect estimation process. The figure explaining the basic view of cost conversion processing. The figure which shows the specific example of the calculation method of a cost effect. The figure which shows another specific example of the calculation method of a cost effect. The figure explaining the update process of a management reference value. The figure explaining a waiting process. The figure which shows the example of a display of performance data. The figure which shows the example of a display of performance data. The figure which shows the example of a display of performance data. The figure which shows the example of a display of performance data.

Explanation of symbols

10 Computer 11 Input Device 12 Display Device 13 Storage Device 14 Reader 15 Work Identification Function 16 Work Time Measurement Function for Each Process 17 All Process Work Time Measurement Function 18 Results DB
19 Performance display function 20, 21 Work 22 ID tag 30 Range setting function 31 Work identification function 32 Work time analysis function 33 Improvement process extraction function required 34 Improvement process presentation function required 35 Range setting support function 40 Expected improvement value setting function 41 Simulation function 42 Improvement effect display function 50 Cost conversion function 51 Improvement process selection function 52 Cost effect display function

Claims (19)

A process improvement support system that supports process improvement of a production line consisting of a plurality of processes,
For each work flowing through the production line, the work total time required for each process and the total process work time required from the start to the end of production are totaled, and the result totaling means for accumulating as actual data together with information on the work,
Range setting means for automatically selecting a range to be improved from all process work time distributions of all workpieces or selecting by a user operation, and work time distribution for each process of workpieces included in the selected range A correlation analysis means including a required improvement process extracting means for extracting one or a plurality of processes having a strong correlation in the selected range as a required improvement process that requires improvement ;
A process improvement support system. The results totaling means is
An operation time measuring means for each process for measuring an operation time for each process for each workpiece;
A whole process work time measuring means for measuring the whole process work time for each workpiece;
A record storage means for storing the measured work time for each process and the total process work time in association with information on the workpiece;
The process improvement support system according to claim 1, comprising: The results totaling means is
A reader that reads the ID tag attached to the workpiece;
The work time measuring unit for each process measures the work time for each process of the process by reading the ID tag at the entrance and exit of the process,
The process improvement support system according to claim 2, wherein the total process work time measuring unit measures the total process work time by reading the ID tag at an entrance and an exit of a production line. The process includes an actual work process in which an actual work is performed on the work, and a wait process in which the work is placed in a waiting state or a moving state before or after the actual work process,
The process improvement support system according to claim 1, wherein the work time for each process includes an actual work time from a work start to a work end in an actual work process and a dwell time in a waiting process. The results totaling means is
Measure the production start time and production end time and the work start time and work end time of each actual work process,
From the production start time and the work start time of the first actual work process, calculate the dwell time before the first actual work process,
From the work end time and production end time of the last actual work process, calculate the residence time after the last actual work process,
The process improvement support system according to claim 4, wherein a residence time between processes is calculated from a work end time of a certain actual work process and a work start time of the next actual work process . The correlation analysis means includes
A work specifying means for specifying a workpiece included in a range that is pre-Symbol selection,
A work time analyzing means for obtaining a difference between the work time distribution for each process of the specific work specified by the work specifying means for each process and the work time distribution for each process of all the works ;
The main improvement process extracting means, a larger one or more steps of differences, we extracted as requiring improvement process,
The process improvement assistance system in any one of Claims 1-5. The range setting means includes
The process improvement support system according to claim 6 , wherein a range to be improved is automatically selected from a distribution range that is longer than an average portion and shorter than a maximum portion among all process work time distributions. The correlation analysis means includes
The whole process work time distribution, the range to be improved, the work time distribution of each specific process for each process and the work time distribution of every work of each work are displayed on a display device. Process improvement support system. The correlation analysis means includes
9. The process improvement support system according to claim 8, wherein when the range to be improved is changed, the display of the work time distribution for each process of the specific workpiece for each process is changed in real time. The correlation analysis means includes
The process according to claim 8 or 9, wherein when a range of the entire process work time distribution or a part of the work time distribution for each process is designated by a user operation, the result data of the work included in the designated range is displayed on the display device. Improvement support system. The information on the workpiece includes the workpiece type and the worker information.
Claim the correlation analyzing means, at least one condition of the model and the operator when it is designated by a user operation, to display the entire process working time distribution and process every operation time distribution of work that matches the designated condition The process improvement assistance system in any one of 8-10. The correlation analysis means includes
The process according to any one of claims 1 to 11, wherein when a process requiring improvement cannot be extracted, the range to be improved is changed, and the process requiring improvement is re-extracted using the range after the change. Improvement support system. The process improvement support system according to any one of claims 1 to 12, further comprising an improvement effect estimation unit that estimates, by simulation, an effect of improvement of a process requiring improvement on all process work times. The improvement effect estimation means includes
Set an assumed improvement value that represents the work time distribution for each process that should be achieved after improvement of the process requiring improvement,
Based on the assumed improvement value that was set and the actual data, the work time distribution of all processes after the improvement was simulated,
The process improvement support system according to claim 13, which displays a distribution of all process work times before and after improvement. 15. The process improvement support system according to claim 13 or 14, further comprising cost effect estimation means for converting the improvement effect of all process work time estimated by the improvement effect estimation means into a cost effect. If there are multiple improvements,
The process improvement support system according to claim 15, wherein the cost effect estimation unit presents improvement plans ranked in descending order of cost effectiveness to the user. The cost effectiveness estimating means includes:
17. The process improvement support system according to claim 16, wherein improvement plans having a cost effect equal to or greater than an investable cost are selected, and the improvement plans are ranked in a descending order of cost effectiveness and presented to the user. A process improvement support method for supporting process improvement of a production line comprising a plurality of processes,
The information processing apparatus, for each of the workpieces through the pre SL production line, the step of aggregating the entire process working time taken until completion of the process for each working time and production started required in each step,
The information processing apparatus, the step of storing the counting result in the storage device as the actual data along with information about the workpiece,
A step in which the information processing device automatically selects a range to be improved from all process work time distributions of all workpieces or selected by a user operation;
The information processing apparatus extracts one or a plurality of processes having a strong correlation with the selected range as a necessary improvement process requiring improvement by referring to the work time distribution for each process of the workpiece included in the selected range. Step to do,
A process improvement support method including A program for causing an information processing apparatus to execute process improvement support processing for supporting process improvement of a production line composed of a plurality of processes,
The program is a program for causing an information processing apparatus to execute each step of the process improvement support method according to claim 18 .

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