JP5510890B2 - Priority determination device - Google Patents

Description

  The present invention relates to a priority determination apparatus that determines the priority of a workpiece in a processing line, and more particularly to a priority determination apparatus that can calculate a highly accurate priority.

  Conventionally, as a processing order of work in a production line or a distribution system, “first in first out” (FIFO) in which work is performed on a work in the order in which they are put into the line, or “delivery priority” is performed in the order of early delivery. Method ".

  Also, a method has been proposed in which the total time required for processing is predicted and the processing priority is set higher in order of increasing margin days (see, for example, Patent Document 1). Here, “margin days” means the number of days obtained by subtracting the predicted value of the remaining work time required for completion of the workpiece from the number of days until the workpiece is delivered.

  By the way, in the case of factories for small-quantity and mass-production, a flow shop type line is used, in which all workpieces are processed in the same process order. And at the factories where the production takes place, a job shop type line is adopted.

  The job shop type line has a work place (work center) for each work process (job) such as machining, sheet metal, painting, inspection, etc., and the work to be repaired or produced is determined in advance for each work. The work of each process is performed by moving to each work place in the order of the processes.

Japanese Patent Laid-Open No. 06-203042

  In the job shop type line, the order of processing steps required to produce and repair workpieces (products) is determined for each workpiece, and the work contents (processes) differ for each work, or even if the work contents are the same, the order is the same. May be different. For this reason, it is difficult for an operator who processes a plurality of works having different work required times, delivery dates, and elapsed processes in the process to determine by himself / herself the work to be prioritized.

  In addition, if the above-mentioned first-in first-out method and delivery date priority method are adopted in the job shop type line, delivery time is delayed for highly urgent goods, and production facilities cannot be used efficiently and overall productivity is lowered. There is a problem to do.

  In addition, in the case of adopting a method in which priority is set higher in the order of fewer days, as in Patent Document 1, if the residence time varies greatly depending on the processing capacity and timing of the process, the required time prediction accuracy decreases. Therefore, there is a problem that it is difficult to calculate the priority with high accuracy.

  In addition, in the case of a method in which priority is set higher in ascending order of the number of days, the remaining work time must have high reliability (prediction accuracy) in order to obtain a highly accurate priority. Is the accumulation of predicted values, and the longer the remaining work time, the lower the reliability. In the case of a work having a long required process, the work in the upstream process has a large predicted part as the remaining work time and its reliability is low, and therefore, depending on the subsequent progress, the work may be completed in a shorter time than the prediction. However, judging only by the number of days, the work in the downstream process (remaining work time is short and the reliability of the value is high) is the work still in the upstream process (remaining work time is long and the reliability of the value is In some cases, the priority is calculated to be lower than (low) and is postponed.

  The present invention has been made in view of the above problems, and an object thereof is to provide a priority determination apparatus capable of calculating a highly accurate priority.

In order to solve the above problem, the priority determination apparatus of the present invention employs the following technical means.
(1) In the present invention, the work place is divided for each of a plurality of work processes, and in the processing line that performs the work of each process in the order of processes determined in advance for each work, the priority of the work when performing the work in each process (A) Among the workpieces to be processed, the number of days to be obtained by subtracting the remaining work time estimated to be required for completion of the workpiece from the number of days until the workpiece is delivered is predetermined. For workpieces that are less than the value and the remaining work time is less than or equal to the predetermined value, the priority of the workpieces is set in descending order of the remaining work time, and (b) the above condition (a) among the workpieces to be processed For workpieces that do not fall under (2), the priority of the workpieces is set higher in the order of the lesser number of days.

  According to the above configuration, priorities are set in the order of decreasing remaining work time for workpieces with less spare days and less remaining work time. Is higher than the work in the upstream process (the remaining work time is long and the reliability of the value is low). Thereby, the accuracy of the priority is increased and the work order of the workpieces is optimized, so that it becomes possible to prevent or reduce delays in delivery. In addition, the worker can easily determine a work to which processing should be prioritized by indicating the “priority” with a unique index.

  According to the present invention, a priority with high accuracy can be calculated.

It is a figure which shows the structure of the priority determination apparatus which concerns on embodiment of this invention. It is a flowchart which shows the priority calculation process in the priority determination apparatus of this invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

FIG. 1 is a configuration diagram showing a priority determination device 10 according to an embodiment of the present invention and a processing line L for processing a plurality of workpieces.
The processing line L in FIG. 1 is a job shop type production line or repair line in which work places are divided for each of a plurality of work processes and the work of each process is performed in a predetermined process order for each work.
In the illustrated example, step 1 to step 5 are assumed to exist. In this case, step 1 is, for example, sheet metal, step 2 is, for example, painting, step 3 is, for example, machining, step 4 is, for example, cleaning, and step 5 is, for example, inspection.

  The process order is determined for each workpiece. For example, as shown in the illustrated example, when there are a work A, a work B, and a work C, it is determined that the work A moves the processes in the order of processes 1, 3, 2, 4, 5, for example. For example, it is determined that the steps are moved in the order of steps 1, 4, 3, and 5, and the workpiece C is determined to be moved in the order of steps 2, 3, 5, and 4, for example.

Here, symbols and terms used below are defined.
(symbol)
i: Work ID
k: Process ID
Si: Days until delivery date of work i Pi: Margin days of work i Wi: Remaining work time of work i

(the term)
The “reserved days” (Pi) is the number of days obtained by subtracting the remaining work time Wi from the number of days Si until the delivery date of the work i.
The “remaining work time” (Wi) is a predicted value of the time (period) required until the work i is completed, and is the sum of “standard work time” and “staying time” in the remaining steps.
The “standard work time” is a statistical value obtained by actual results or simulation of the work time required to process the workpiece i in a certain process k, and is determined for each process.
“Residence time” is an actual value of waiting time from when a workpiece enters the process until the work starts, or a statistical value obtained by simulation, and is determined for each process.

  The priority determination apparatus 10 of the present invention is an apparatus that determines the priority of a work when performing work in each process on a processing line, and includes a priority setting means 11. The priority determination apparatus 10 can be configured by a general-purpose computer in which a program for executing priority calculation processing described below is installed, or a dedicated computer in which priority calculation processing is programmed in advance.

  As described above, in the calculation of the priority according to the prior art as represented by Patent Document 1, a calculation method in which the priority is set higher in the order of the fewest days is used. On the other hand, in the calculation of the priority by the priority setting means 11, a calculation method that takes into account the remaining work time in addition to the number of days for each work is adopted. A specific priority calculation processing procedure in the priority setting means 11 will be described later.

  In the priority determination device 10, in order to calculate the priority reflecting the daily progress, information regarding the workpiece at the time of performing the calculation is used. For example, the priority is calculated before starting work for a predetermined period (daily or hourly) during which the processing line is operated, and priorities are set for all workpieces to be processed. Then, work is processed according to priority. In order to reflect the current progress in the next operation period (operation day or operation time), a new priority calculation is performed using the updated information, that is, the information at the time when the calculation is performed. Work is processed according to priority. This is performed every operation period.

  Information (data) necessary for calculating the priority is input from the input device 14. In order to calculate the priority based on the spare days Pi for each work i in the priority setting means 11, the spare days Pi and the remaining work time Wi are required.

  In calculating the priority based on the allowance days Pi, the allowance days Pi and the remaining work time Wi may be input from the input device 14 and used as they are in the priority setting means 11. Alternatively, for the spare days Pi and the remaining work time Wi, information for calculating them is input from the input device 14, and the priority setting means 11 calculates the spare days Pi and the remaining work time Wi based on these information. May be.

  In this case, the information for calculating the margin days Pi is the number of days Si until delivery date (or delivery date / time and current date / time) and the remaining work time Wi. Information for calculating the remaining work time Wi is the standard work time and residence time in each process, the process path of the work i, and the current process progress.

  The input device 14 may be an input means operated by a person such as a keyboard, or may be a management system having a database (storage device) in which a work state (location or progress) is managed. Alternatively, when the work state (location or progress) is automatically managed for each work i using an IC tag, the automatic management system may be used.

  The priority calculated by the priority determination device 10 is output to the output device 15 in an expression format that allows the operator to identify the priority, such as numbers and characters. The output form by the output device 15 may be a screen display by a monitor or printing by a printer.

FIG. 2 is a flowchart of the priority calculation process in the priority setting unit 11.
First, (a) among the workpieces to be processed, the number of days remaining until the work delivery date is subtracted from the remaining work time Wi of the work is equal to or less than a predetermined value (x days), and the remaining work time is a predetermined value. (Y day) For the following works, the priority of the work is set higher in the order of the remaining work time Wi (S1).

  Next, among the workpieces to be processed (b), for the workpieces that do not meet the condition (a), the priorities of the workpieces are set higher in the order of the lesser number of days Pi (S2).

Here, as an example, the priorities are calculated for the workpieces under the conditions shown in [Table 1] below, according to the related art and the present invention.

  When priorities are set higher in the order of decreasing margin days for workpieces A to G as in the prior art, workpiece C and workpiece F have the same margin days, so there is no difference in priority and the remaining work time In some cases, work F is given priority over work C (that is, the reliability of the predicted value is low). Of the workpieces with less days (less than 10 days), B and F have a short remaining work time (= reliability of the predicted value) even though the remaining work time is long and the reliability of the predicted value is low. Higher priority) than work A, C, E. As a result, the workpieces A, C, and E are later than the workpieces B and F. Also, if the priority is set higher in the order of fewer days between the workpieces A, C, and E, the order of E, A, and C becomes the order, and the workpiece C that has a shorter remaining work time has a longer remaining work time. The priority is set lower than those of the workpieces A and E which are long and inferior in the reliability of the predicted value.

  On the other hand, the priority calculated by the present invention is as follows. Considering the case where x = 10 days and y = 5 days are set in (a), among the workpieces in Table 1, workpieces to be processed in (a) are A, C, and E. If the priorities are set higher for the workpieces A, C, and E in the order of the remaining work time Wi, the priorities are C, A, and E in the descending order. Next, for works B, D, F, and G that do not fall under (a) above, if the priority is set higher in the order of the lesser number of days Pi, the priorities are B, F, G, and D in descending order. Become.

  Therefore, when the present invention is applied, the priority as a whole is C, A, E, B, F, G, D in descending order. As a result, unlike the priorities calculated by the prior art, the workpieces A, C, and E are processed before the workpieces B and F that have a long remaining work time, and are not postponed. In addition, between the workpieces A, C, and E, the workpiece C is set higher in priority than the workpieces A and E that have a longer remaining work time than the workpieces A and E that are inferior in reliability of the predicted value. Note that, in the above, the values of x and y may be adjusted to suit the characteristics of the work to be handled and the processing.

  According to the priority determination device 10 of the present invention described above, since the priority is set higher in the order of the remaining work time Wi for the work having the lesser number of days Pi and the remaining work time Wi, the work in the downstream process ( The remaining work time is short and the reliability of the value is high) and the work in the upstream process is long (the remaining work time is long and the reliability of the value is low). Thereby, the accuracy of the priority is increased and the work order of the workpieces is optimized, so that it becomes possible to prevent or reduce delays in delivery. In addition, the worker can easily determine a work to which processing should be prioritized by indicating the “priority” with a unique index.

[Table 2] below shows a simulation result when the production line is operated using the priority calculated by the priority determination device 10. Table 2 shows comparison values of the following items (a) to (c) in units of products (= a state in which all components are available).
(A) Average excess days: Average number of days that work has exceeded delivery date (b) Excess rate rate (%): All parts whose work has exceeded delivery date Ratio to the number of products (c) Average TAT (days): TAT average value of all products (TAT: Turn Around Time is the time between the earliest input part introduction date and the latest completion part completion date among the component parts of the product. Days)

  From Table 2, the priority determination device 10 of the present invention reduces the number of parts exceeding the delivery date to about one-fourth compared to the FIFO (first-in first-out method), and the average TAT is also reduced by 20 days or more. You can see that it can be improved.

  Although the embodiments of the present invention have been described above, the embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is not limited to these embodiments. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

L processing line 10 priority determining device 11 priority setting means 14 input device 15 output device

Claims (1)

Priority determination that determines the priority of work when performing work in each process in a processing line where the work place is divided for each work process and the work of each process is performed in a predetermined process order for each work A device,
(A) Among the workpieces to be processed, the number of days remaining after subtracting the remaining work time estimated to be required to complete the work from the number of days until the work delivery date is less than or equal to a predetermined value, and the remaining work time is less than or equal to a predetermined value for the work, and it sets a higher priority for the work in order remaining working time is small, for each work which does not correspond to the above conditions (a) of the workpiece to be (b) processed, the above Priority determination characterized by comprising priority setting means for setting the priorities of workpieces in descending order of margin days so that the priorities of the workpieces satisfying the condition (a) are lower than the priorities of the workpieces. apparatus.