Method and program for optimizing circuit board production lines

Abstract

To both reduce a time required for optimization processing and improve production efficiency.SOLUTION: A method for optimizing a circuit board production line that includes multiple machines that sequentially perform operations to produce the circuit board is a method for optimizing the production of the circuit board using the circuit board production line includes a first optimization step (S1) of performing an optimization process at a specified level to optimize a production program so as to improve the production efficiency of the circuit board, a determination step (S2, S3) of determining whether or not a bottleneck machine exists with lower production efficiency than another machine when producing a circuit board according to the production program after the optimization process, and a second optimization step (S7, S8) of raising the optimization level, which is the level at which optimization is pursued, only for the bottleneck machine, and re-executing the optimization process of the production program when it is determined that a bottleneck machine exists.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a technique for producing substrates using a production line including a plurality of machines that sequentially perform operations for producing the substrates. [Background technology]

[0002] When producing boards using a board production line including a plurality of machines, it is desirable to optimize the work of each machine as much as possible and improve the production efficiency of the boards.

[0003] For example, Patent Document 1 below discloses a device that optimizes the component mounting order at each mounter and the allocation of component responsibilities among the mounters in a mounting line that includes multiple mounters that mount components onto boards. This optimization device is said to shorten and equalize the cycle time at each mounter, thereby improving the production efficiency of boards. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-71478 Summary of the Invention [Problem to be solved by the invention]

[0005] There is a trade-off between the improvement in production efficiency achieved by optimization processing and the time required for the optimization processing. In other words, it takes an enormous amount of time to optimize all optimization targets on a production line to the maximum extent. Therefore, it is conceivable to select optimization targets that have a large impact on production efficiency and focus on optimizing those optimization targets, but it is not easy for an operator to select optimization targets that have a large impact on production efficiency at their own discretion. For this reason, in the past, it was necessary to choose between prioritizing the result of improving production efficiency and allocating a lot of time to the optimization processing, or not prioritizing the result so much and saving time on the optimization processing.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide an optimization method and an optimization program for a board production line that can achieve both a reduction in the time required for optimization processing and an improvement in production efficiency. [Means for solving the problem]

[0007] In order to solve the above problem, one aspect of the present invention provides a method for optimizing a board production line, which method optimizes the production of boards using a board production line including a plurality of machines that perform tasks to produce boards in sequence, and includes: a first optimization step of performing an optimization process at a specified level to optimize a production program that controls the board production line so as to improve the production efficiency of the boards; a judgment step of determining whether or not a bottleneck machine exists that has lower production efficiency than other machines when the boards are produced using the production program after the optimization process in the first optimization step; and a second optimization step of, if it is determined in the judgment step that a bottleneck machine exists, raising the optimization level, which is the level at which optimization is pursued, only for the bottleneck machine and re-executing the optimization process of the production program.

[0008] According to the present invention, a production program with its optimization level kept at a specified level is evaluated from the perspective of production efficiency. If the evaluation reveals the presence of a bottleneck machine with relatively poor production efficiency, the optimization level of the bottleneck machine is raised. This allows optimization to be limited to the bottleneck machine, enabling a new production program with superior production efficiency to be updated in a relatively short time. For example, if optimization were pursued without checking for the presence of a bottleneck machine, it would be necessary to raise the optimization level for all machines in the board production line, which could significantly increase the time required for calculation. In contrast, according to the present invention, the optimization level is raised only for the bottleneck machine that is deteriorating the production efficiency of the board production line. This allows optimization to be pursued by focusing on the optimization target within the bottleneck machine, thereby shortening the time required for optimization calculation. The production program obtained by this calculation, i.e., a new production program in which optimization of the bottleneck machine is pursued, is likely to improve the efficiency of the bottleneck machine's work and result in improved board production efficiency. Therefore, according to the present invention, it is possible to improve board production efficiency while shortening the time required for the optimization process.

[0009] Preferably, in the determining step, a cycle time, which is the work time per substrate, is obtained for each of the plurality of machines, and the machine with the longest cycle time is identified as the bottleneck machine.

[0010] In this manner, the bottleneck machine can be appropriately identified based on the cycle time of each machine.

[0011] Preferably, in the determination step, an average cycle time, which is the average value of the cycle times of the plurality of machines, is compared with a longest cycle time, which is the cycle time of the machine with the longest cycle time, and if the longest cycle time is greater than the average cycle time by a predetermined percentage or more, the machine with the longest cycle time is identified as the bottleneck machine.

[0012] In this manner, only if there is a machine with a significantly long cycle time can it be identified as a bottleneck machine and its optimization pursued.

[0013] Preferably, the optimization method further includes a balancing step of performing line balancing to allocate work from the bottleneck machine to other machines if it is determined in the determination step that the bottleneck machine exists, and the second optimization step is executed if the bottleneck machine still exists after the balancing step.

[0014] In this mode, in cases where the cycle time can be improved by smoothing the work distribution among multiple machines (line balancing), it is possible to pursue optimization of the bottleneck machine after achieving the improvement through such smoothing. In other words, since line balancing takes priority over raising the optimization level of the bottleneck machine, it is possible to pursue optimization of the bottleneck machine only if a bottleneck machine still exists even after line balancing, thereby making it possible to rationally improve the production efficiency of boards.

[0015] Preferably, the optimization method further includes a prediction step for predicting whether there is room for improvement in the cycle time of the bottleneck machine after the balance adjustment step, and the second optimization step is executed only if it is determined by the prediction step that there is room for improvement.

[0016] In this embodiment, optimization of the bottleneck machine is pursued only when there is a possibility of improvement, so that it is possible to prevent unnecessary increases in calculation time.

[0017] Preferably, the optimization method further includes a presentation step of presenting to an operator information including each cycle time before and after performing the second optimization step.

[0018] In this manner, the operator can easily understand the change in cycle time that occurs due to raising the optimization level of the bottleneck machine, and based on this information, the operator can appropriately determine, for example, the timing to switch production programs.

[0019] An optimization program for a board production line according to another aspect of the present invention is a program for optimizing the production of boards using a board production line including a plurality of machines that perform tasks to produce boards in sequence, and causes a computer to execute processes including: a first optimization process that performs an optimization process at a specified level to optimize the production program that controls the board production line so as to improve the production efficiency of the boards; a judgment process that determines whether or not a bottleneck machine exists that has lower production efficiency than other machines when the boards are produced using the production program after the first optimization process; and a second optimization process that, if it is determined in the judgment process that a bottleneck machine exists, raises the optimization level, which is the level at which optimization is pursued, only for the bottleneck machine and re-executes the optimization process for the production program.

[0020] According to this optimization program invention, it is possible to obtain the same effects as the optimization method invention described above. [Effects of the Invention]

[0021] As described above, according to the present invention, it is possible to achieve both a reduction in the time required for optimization processing and an improvement in production efficiency. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a plan view showing a schematic configuration of a board production line to which an optimization method according to an embodiment of the present invention is applied; [Figure 2] 10 is a flowchart showing the content of processing performed by the program creation device. [Figure 3]3 is a subroutine showing details of the processing of step S1 in FIG. 2. [Figure 4] FIG. 10 is a diagram showing the contents of the initial conditions that are the basis for creating a production program. [Figure 5] 10 is a graph showing the relationship between the upper limit of calculation time and the optimization level, and the relationship between the upper limit of the number of trials and the optimization level. [Figure 6] 10 is a table illustrating an example of cycle times of a plurality of mounting machines and the bottleneck machine determination results based on the cycle times. [Figure 7] 10 is a table showing an example of program information presented to an operator before the optimization level of a bottleneck machine is increased. [Figure 8] 10 is a table showing an example of program information presented to an operator after the optimization level of a bottleneck machine is increased. DETAILED DESCRIPTION OF THE INVENTION

[0023] [Configuration of PCB production line] FIG. 1 is a plan view showing a schematic configuration of a board production line 1 to which an optimization method according to one embodiment of the present invention is applied. The board production line 1 is a facility for producing boards P, and includes, in order from the upstream side in the conveyance direction of the board P, a first mounting machine 11, a second mounting machine 12, and a third mounting machine 13. Each of the mounting machines 11-13 is a machine that mounts electronic components (hereinafter simply referred to as components) on the top surface of the board P. The board P produced through the work of each of the mounting machines 11-13 includes a bare board (printed wiring board) before components are mounted thereon and a plurality of components mounted on the top surface of the bare board. In other words, the work target of each of the mounting machines 11-13 is a board on which at least some components are not mounted. However, in this embodiment, such a board in the middle of production and a board on which mounting has been completed will not be distinguished and will both be referred to as the board P. Although not shown, other machines such as a printer that prints cream solder on the top surface of the substrate P may be located upstream of the first mounting machine 11, and other machines such as a reflow furnace or inspection device may be located downstream of the third mounting machine 13.

[0024] The first to third mounting machines 11 to 13 are lined up consecutively in the direction in which the board P is transported by a conveyor 22, which will be described later, so as to perform component mounting work on the board P in order. The first to third mounting machines 11 to 13 have the same basic configuration, and the configuration of the first mounting machine 11 will be described below as a representative.

[0025] The first mounting machine 11 includes a base 21, a conveyor 22, a head unit 23, a moving mechanism 24, and a plurality of component supply devices 25. The X direction in Fig. 1 is a direction parallel to the transport direction of the substrate P, and the Y direction is a direction perpendicular to the X direction in the horizontal plane.

[0026] Conveyor 22 is a conveyor that transports board P, and is disposed on base 21 so as to extend in the X direction. Conveyor 22 transports board P from the +X side into first mounting machine 11, transports it to the -X side to a predetermined work position (the position of board P shown in FIG. 1), and stops it there. At this work position, components are mounted on board P. After the mounting work, conveyor 22 transports board P further to the -X side and takes it out of first mounting machine 11.

[0027] The movement mechanism 24 is a mechanism that supports the head unit 23 so that it can move in the X and Y directions. The movement mechanism 24 includes a support frame 31 that extends in the X direction, a pair of Y-axis movement mechanisms 32 that move the support frame 31 in the Y direction, and an X-axis movement mechanism 33 that moves the head unit 23 in the X direction relative to the support frame 31. As the Y-axis movement mechanism 32 and the X-axis movement mechanism 33, for example, a ball screw mechanism can be used.

[0028] Head unit 23 is movable in the Y direction in accordance with the movement of support frame 31, and is also movable in the X direction along support frame 31. Head unit 23 is equipped with multiple suction heads that can be raised and lowered and that suck and hold components to be mounted on substrate P. The suction heads suck and hold components at the component removal position of component supply device 25, move the components above substrate P, and mount the components at predetermined mounting positions on substrate P.

[0029] Each of the multiple component supply devices 25 is a device that supplies components to be mounted on the board P. In this embodiment, a total of four component supply devices 25 are prepared on the base 21, with two component supply devices 25 arranged in each of the +Y side and -Y side areas across the conveyor 22. The components supplied by the component supply devices 25 are small electronic components such as integrated circuits (ICs), transistors, resistors, and capacitors.

[0030] Each component supply device 25 includes a plurality of tape feeders 26 arranged in the X direction. Each tape feeder 26 supplies components to the component removal position using a component storage tape containing the components as a carrier. Note that the feeders constituting each component supply device 25 are not limited to tape feeders 26, and other feeders such as tray feeders that supply packaged components placed on a tray may also be used.

[0031] The configuration of the first mounting machine 11 has been explained above, but the second mounting machine 12 and the third mounting machine 13 have the same configuration.

[0032] [Control system] Next, we will explain the control system of board production line 1. Board production line 1 is electrically connected to production control device 41 and program creation device 42. Production control device 41 is a device that controls the production of boards P carried out by board production line 1, which includes first to third mounting machines 11 to 13. Program creation device 42 is a device that creates and updates the production program used by production control device 41. Production control device 41 and program creation device 42 are configured by a microcomputer that includes a processor (CPU) that performs calculations, and memories such as ROM and RAM.

[0033] The program creation device 42 is connected to the production control device 41 via a network LN, and creates and updates a production program and transmits it to the production control device 41. The production control device 41 is connected to the first to third mounting machines 11 to 13 via the network LN, and controls each of the mounting machines 11 to 13 based on the production program acquired from the program creation device 42.

[0034] An input unit 43 and a display unit 44 are electrically connected to the program creation device 42. The input unit 43 is an interface for inputting various data to the program creation device 42, and is composed of, for example, a keyboard, a mouse, etc. The display unit 44 is a display for presenting input / output data and the like for the program creation device 42 to an operator.

[0035] [Optimization process] Next, the process of creating and updating a production program by program creation device 42 will be described. Note that the process of creating and updating a production program referred to here includes an optimization process of optimizing the production program so as to improve the production efficiency of boards P by board production line 1. That is, program creation device 42 creates a production program at a specified optimization level, and then updates the production program while appropriately raising the optimization level. This will be described in detail below.

[0036] 2 is a flowchart showing the details of the processing performed by the program creation device 42. The processing shown in this flowchart is started in response to an instruction from an operator via the input unit 43. When the processing is started, the program creation device 42 creates a production program based on various predetermined conditions (step S1).

[0037] 3 is a subroutine showing the details of the processing of step S1. As shown in this figure, when the creation of a production program starts, the program creation device 42 reads predetermined basic data and optimization level (step S11). The basic data and optimization level are set in advance by an operator's operation via the input unit 43, for example.

[0038] 4, the basic data includes board data, board handling conditions, and mounting machine data. The board data is data including information such as the types of components to be mounted on the board P and the mounting coordinates of each component. The board handling conditions are data including information such as the transport speed of the board P. The mounting machine data is data including information such as the position of the component supply device 25 (tape feeder 26) in each mounting machine 11-13, the mounting operation position of the board P, and the movement speed of the head unit 23.

[0039] The optimization level is the level at which the optimization of the production program is pursued, and the higher the optimization level, the more efficient the production program that is created. The targets of optimization can be, for example, the arrangement of components in the component supply device 25 of each of the mounting machines 11 to 13 (in other words, the order of the tape feeders 26), the order in which components are mounted by the head units 23 of each of the mounting machines 11 to 13, and the division of work among the mounting machines 11 to 13 (the allocation of which components are mounted by which mounting machine).

[0040] The optimization level when creating a production program in step S1 can be defined by simple numerical values ​​such as level 1, level 2, level 3, etc., but in this embodiment, the optimization level is defined based on two parameters: an upper limit on calculation time and an upper limit on the number of attempts. The upper limit on calculation time is the upper limit on the amount of time allowed to be consumed to generate one solution, and the upper limit on the number of attempts is the upper limit on the number of times the generation of a solution and its evaluation are allowed to be repeated. As shown in Figure 5, the longer the upper limit on calculation time, the higher the optimization level, and the higher the upper limit on the number of attempts, the higher the optimization level.

[0041] The upper limit calculation time and the upper limit number of attempts are input in advance into the program creation device 42 by the operator operating the input unit 43. The upper limit calculation time and the upper limit number of attempts can be set by directly inputting the numerical values, or by selecting one from a plurality of options such as "large," "medium," or "small." In the following, the set upper limit calculation time is represented as T, and the set upper limit number of attempts is represented as N.

[0042] In step S11, the program creation device 42 reads the basic data and optimization level (upper limit calculation time T and upper limit number of trials N) that have been set in advance as described above. Thereafter, the program creation device 42 generates one solution by calculation using the upper limit calculation time T (step S12). That is, the program creation device 42 repeats the process of changing the optimization target (component placement, mounting order, work allocation, etc.) as many times as necessary within the upper limit calculation time T, and evaluates and compares the solution candidates obtained by each process from the perspective of production efficiency. Then, when the calculation time reaches the upper limit calculation time T, the solution candidate with the highest production efficiency is extracted, and the extracted solution candidate is output as the solution that is the result of step S12.

[0043] Specifically, the program creation device 42 evaluates the production efficiency of each solution candidate based on the cycle time, which is the time required to produce one board P (the work time per board). Each solution candidate has a different optimization target, such as component placement, mounting order, and work allocation, so the cycle time may also differ. The program creation device 42 predicts the cycle time of each solution candidate by simulation or the like, and evaluates each solution candidate based on the predicted cycle time. That is, when the calculation time reaches the upper limit calculation time T, the program creation device 42 extracts the solution candidate with the shortest cycle time among the solution candidates obtained so far, and outputs the extracted solution candidate as the solution.

[0044] Next, the program creating device 42 determines whether or not the number of trials, which is the number of times a solution has been generated in step S12, has reached the upper limit number of trials N read in step S11 (step S13).

[0045] If the determination in step S13 is NO and it is confirmed that the number of trials is less than the upper limit number of trials N, the program creation device 42 returns to step S12 and repeats the generation of a solution. That is, the program creation device 42 uses the solution generated by the previous calculation as a starting point and further repeats the process of changing the optimization target within the upper limit calculation time T, and outputs the solution candidate with the shortest cycle time (highest production efficiency) as a new solution.

[0046] On the other hand, if the result of the determination in step S13 is YES and it is confirmed that the number of trials has reached the upper limit N, the program creation device 42 evaluates the N solutions generated through steps S12 and S13 from the viewpoint of production efficiency (step S14), extracts the solution with the shortest cycle time, and outputs the extracted solution as a production program (step S15).

[0047] Once the creation of the production program is completed through the above-described processes, the flow proceeds to step S2 in FIG. 2. In step S2, the program creation device 42 compares the cycle times of the first to third mounting machines 11-13 when mounting (producing) the board P in accordance with the created production program, and extracts the mounting machine with the longest cycle time as the machine with the longest CT time. The cycle time here refers to the work time consumed by each mounting machine 11-13 for one board P. For example, the cycle time of the first mounting machine 11 can be the time from when the board P is carried into a predetermined work position within the first mounting machine 11 until the next board P is carried into that work position. Note that in step S2, if there are multiple mounting machines with the same cycle time, these multiple mounting machines may be extracted as the machines with the longest CT time. In other words, the number of longest CT machines is not limited to one, and there may be multiple machines.

[0048] The cycle times of the mounting machines 11-13 compared to each other to extract the machine with the longest CT time may be values ​​predicted by simulation or may be values ​​measured. For example, depending on the urgency of production of the board P, production of the board P may be started immediately using the production program created in step S1, that is, before the processes of steps S7 and S8, which will be described later and aim to optimize the production program, are performed. Alternatively, an operator desiring to obtain highly accurate cycle times may perform test production of boards P to measure the cycle times. In such cases, the cycle times of the mounting machines 11-13 according to the production program (step S1) may be determined by actual measurement. Conversely, if no actual measured cycle times exist, the machine with the longest CT time is extracted in step S2 based on the predicted cycle times obtained by simulation.

[0049] Next, the program creation device 42 determines whether the machine with the longest CT time extracted in step S2 corresponds to a bottleneck machine (step S3). Specifically, the program creation device 42 compares the longest cycle time, which is the cycle time of the machine with the longest CT time extracted in step S2, with the average cycle time, which is the average value of the cycle times of the first to third mounting machines 11 to 13. Then, if the longest cycle time is greater than the average cycle time by a predetermined percentage or more, it determines that the machine with the longest CT time corresponds to a bottleneck machine.

[0050] The predetermined ratio can be, for example, 5%. In this case, if the increase in the longest cycle time relative to the average cycle time is 5% or more, the machine with the longest CT time is treated as a bottleneck machine. If the increase is less than 5%, the machine with the longest CT time is not treated as a bottleneck machine. A specific example is shown in FIG. 6. In this example, the cycle time of the first mounting machine 11 is 25 seconds, the cycle time of the second mounting machine 12 is 30 seconds, and the cycle time of the third mounting machine 13 is 26 seconds. In this case, the second mounting machine 12 is the machine with the longest CT time, with a longest cycle time of 30 seconds and an average cycle time of 27 seconds. Furthermore, the increase in the longest cycle time relative to the average cycle time is approximately 11%, which is greater than 5%. Therefore, the second mounting machine 12, which is the machine with the longest CT time, corresponds to a bottleneck machine.

[0051] If the result of the judgment in step S3 is NO and it is confirmed that the machine with the longest CT is not a bottleneck machine, the program creation device 42 judges that the production program created in step S1 is a program with sufficiently high production efficiency, and presents it to the operator as the result (step S9).

[0052] For example, as shown in FIG. 7, the program creation device 42 presents to the operator via the display unit 44 one line of tabular information indicating that one type of production program has been created. The presented information includes, for example, the cycle time (CT) when the board P is produced using the production program, the optimization level of each of the mounting machines 11-13, and information on the processing time. In FIG. 7, the estimated CT refers to an estimated value obtained by simulating the cycle time, and the actual CT refers to the actual measured value of the cycle time. Note that the cycle time here refers to the overall cycle time of the board production line 1, in other words, the cycle time of the machine with the longest CT. At this point, the processes of steps S7 and S8, which will be described later and which pursue optimization, have not been performed, so "1" is displayed as the optimization level for each of the first mounting machines 11-13.

[0053] On the other hand, if the answer to step S3 is YES and it is confirmed that the machine with the longest CT is a bottleneck machine, the program creation device 42 determines whether the line balance adjustment in step S5 described below has been performed (step S4).

[0054] If the determination in step S4 is YES and it is confirmed that line balance adjustment has not been performed, the program creation device 42 performs line balance adjustment (step S5). Line balance adjustment is a process of allocating part of the work of a bottleneck machine to other machines. For example, if the second mounting machine 12 is the bottleneck machine as shown in FIG. 6, the program creation device 42 performs the line balance adjustment by updating the production program so that part of the work of the second mounting machine 12 is allocated to the other mounting machines 11 and 13. There are various possible ways to allocate work, and one possible method is to allocate part of the component mounting work that was to be performed by the bottleneck machine to other machines.

[0055] After the line balance adjustment in step S5 is performed, the process returns to step S2 and the subsequent steps are repeated. That is, the presence or absence of a bottleneck machine is checked based on the cycle time of each of the mounting machines 11 to 13 after the line balance adjustment.

[0056] On the other hand, if the result of the determination in step S4 is NO and it is confirmed that the line balance adjustment has already been performed, the program creation device 42 determines whether there is room for improvement by raising the optimization level of the bottleneck machine in step S7 (described later) (step S6). This determination can be, for example, a prediction determination based on past trends.

[0057] That is, if the optimization level of the bottleneck machine has already been increased at least once (S7), it is possible to predict whether there is room for improvement based on the change trend of the bottleneck machine's cycle time before and after this past optimization level increase. For example, if a past increase in the optimization level resulted in a decrease in cycle time, it is possible to predict that there is still room for improvement, and if a past increase in the optimization level resulted in almost no decrease in cycle time, it is possible to predict that there is no room for improvement. Note that if the optimization level of the bottleneck machine has never been increased (S7) at present, that is, if the past trend is unknown, it is sufficient to unconditionally predict that there is room for improvement.

[0058] The prediction of room for improvement is not limited to being based on past trends as described above. For example, if there is a program created under similar conditions to the current program among the production programs created by the program creation device 42, the presence or absence of room for improvement may be predicted based on the track record when this similar program was created.

[0059] If the result of the determination in step S6 is NO and it is confirmed that the prediction of room for improvement is negative, the program creation device 42 presents the results obtained up to that point to the operator (step S9).

[0060] On the other hand, if the determination in step S6 is YES and the prediction of room for improvement is confirmed to be positive, the program creation device 42 raises the optimization level of the bottleneck machine (step S7) and updates the production program based on the raised optimization level (step S8). That is, the program creation device 42 generates multiple solutions based on the most recently created production program, with only the optimization target of the bottleneck machine changed, and outputs the solution with the shortest cycle time among them as a new production program.

[0061] 6, if the second mounting machine 12 is a bottleneck machine, the program creation device 42 generates multiple solutions by changing the optimization targets, such as the arrangement of components in the component supply device 25 of the second mounting machine 12 (the arrangement order of the tape feeders 26) and the mounting order of components on the second mounting machine 12. Then, from among the generated solutions, the solution with the shortest cycle time for the second mounting machine 12 is extracted and output as a new production program. Such updates to the production program are performed so as to fit within a predetermined upper limit of the calculation time or number of trials.

[0062] Once the production program update in steps S7 and S8 is complete, the process returns to step S2 and repeats the subsequent steps. That is, the presence or absence of a bottleneck machine is checked based on the cycle time of each mounting machine 11-13 after the program update (S2, S3). If it is confirmed that a bottleneck machine still exists, room for improvement in the cycle time is predicted to determine whether the optimization level of the bottleneck machine should be further increased (S6). If it is predicted that there is room for improvement, the optimization level of the bottleneck machine is further increased and the production program is updated (S7). Conversely, if it is predicted that there is no room for improvement, the results obtained so far are presented to the operator via the display unit 44 (S9).

[0063] FIG. 8 shows an example of information presented to the operator when the optimization level is raised in step S9. In this figure, information on three types of production programs, No. 1 to No. 3, is presented as the result of raising the optimization level of a bottleneck machine twice. No. 1 is information on the production program before the optimization level of the bottleneck machine was raised, i.e., the production program obtained by performing line balance adjustment (S5) on the initially created program (S1). Since the optimization level has not yet been raised at this point, the optimization levels of the first to third mounting machines 11 to 13 in the No. 1 program are all marked as "1." No. 2 is information on the production program obtained by raising the optimization level of the second mounting machine 12, which is the bottleneck machine, by one level. In the No. 2 program, the optimization level of the second mounting machine 12 is raised to "2," while the optimization levels of the other mounting machines are maintained at "1." No. 3 is production program information obtained by further raising the optimization level of the second mounting machine 12 (bottleneck machine) by one level. In this program No. 3, by further raising the optimization level of the second mounting machine 12, the notation of the optimization level of the second mounting machine 12 increases to "3," while the notation of the optimization levels of the other mounting machines remains "1." Furthermore, considering the cycle time values ​​shown in Figure 8, it can be seen that the cycle time is shortened as the production program is updated from No. 1 to No. 2 to No. 3.

[0064] In the flowchart of FIG. 2 described above, the processing of step S1 corresponds to the "first optimization step" or "first optimization processing" in the present invention, the processing of steps S2 and S3 corresponds to the "determination step" or "determination processing" in the present invention, the processing of step S5 corresponds to the "balance adjustment step" in the present invention, the processing of step S6 corresponds to the "prediction step" in the present invention, the processing of steps S7 and S8 corresponds to the "second optimization step" or "second optimization processing" in the present invention, and the processing of step S9 corresponds to the "presentation step" in the present invention.

[0065] [Actions and effects] As explained above, in this embodiment, after a production program (S1) is created at a specified optimization level, it is determined whether or not a bottleneck machine with a relatively long cycle time exists (S2, S3), and if the determination confirms that a bottleneck machine exists, the optimization level is raised only for that bottleneck machine and the optimization process is re-executed (S7, S8). This configuration has the advantage of being able to improve the production efficiency of the substrate P while shortening the time required for the optimization process.

[0066] That is, in this embodiment, a production program with its optimization level kept at a specified level is evaluated from the perspective of cycle time (production efficiency). If the evaluation reveals the existence of a bottleneck machine with a relatively long cycle time (low production efficiency), the optimization level of the bottleneck machine is raised. This allows optimization to be limited to the bottleneck machine, enabling the program to be updated to a new one with superior production efficiency in a relatively short time. For example, if optimization were pursued without checking for the existence of a bottleneck machine, the optimization level would need to be raised for all of the first through third mounting machines 11-13, potentially significantly increasing the time required for calculation. In contrast, in this embodiment, the optimization level is raised only for the bottleneck machine that is deteriorating the production efficiency of the board production line 1. This allows optimization to be pursued by focusing on the optimization target (component placement, mounting order, etc.) within the bottleneck machine, thereby reducing the time required for optimization calculation. The production program obtained by this calculation, i.e., a new production program in which the bottleneck machine has been optimized, is likely to improve the efficiency of the bottleneck machine's operations and shorten the cycle time of the board production line 1. Therefore, according to this embodiment, it is possible to improve the production efficiency of the substrate P while shortening the time required for the optimization process.

[0067] Furthermore, in this embodiment, the longest cycle time, which is the cycle time of the mounting machine with the longest cycle time (longest CT machine), is compared with the average cycle time, which is the average value of the cycle times of the first to third mounting machines 11 to 13, and if the former is higher than the latter by a predetermined percentage (for example, 5%) or more, the longest CT machine is determined to be a bottleneck machine. With this configuration, it is possible to appropriately identify bottleneck machines based on significant differences in cycle times.

[0068] Furthermore, in this embodiment, when the presence of a bottleneck machine is confirmed, line balancing is first performed to allocate the work of that bottleneck machine to other machines, and if a bottleneck machine still exists after line balancing, the optimization level of the bottleneck machine is raised. With this configuration, in cases where the cycle time can be improved by smoothing the work allocation (line balancing) among the mounting machines 11-13, it is possible to pursue optimization of the bottleneck machine after achieving improvements through such smoothing. In other words, since line balancing is performed with priority over raising the optimization level of the bottleneck machine, optimization of the bottleneck machine can be pursued only if a bottleneck machine still exists after line balancing, thereby rationally improving the production efficiency of the board P.

[0069] Furthermore, in this embodiment, after the above-described line balance adjustment, a prediction is made as to whether there is room for improving the cycle time of the bottleneck machine, and if the prediction is positive, the optimization level of the bottleneck machine is raised. With this configuration, optimization of the bottleneck machine is pursued only when there is a possibility of improvement, thereby preventing unnecessary increases in calculation time.

[0070] Furthermore, in this embodiment, when the optimization level of a bottleneck machine is raised and a production program is updated, information including the cycle times before and after the update process is presented to the operator. This configuration allows the operator to easily understand the change in cycle time that has occurred as a result of raising the optimization level of the bottleneck machine. Therefore, based on this information, the operator can appropriately determine, for example, the timing to switch production programs.

[0071] For example, in a situation where production of substrates P has already begun using a production program before the optimization level of a bottleneck machine was raised, and a program update with the optimization level raised is being performed in parallel, the operator can appropriately determine the timing to switch the production program based on the magnitude of the change (improvement) in cycle time. Specifically, if the improvement in cycle time due to raising the optimization level is large, it can be determined that it is better to switch the production program early even if it means temporarily suspending the production of substrates P. Conversely, if the improvement in cycle time due to raising the optimization level is small, it can be determined that it is better to switch the production program after a break in production, such as a change in lot, arrives.

[0072] In the above embodiment, an example was described in which the optimization method of the present invention was applied to a board production line 1 including three mounting machines, namely, first to third mounting machines 11 to 13. However, the board production line to which the optimization method of the present invention can be applied is not limited to a line including multiple mounting machines, as long as it includes multiple machines that perform work to produce boards in sequence. For example, the present invention can also be applied to a line that includes at least one mounting machine and other machines, or a line that includes multiple machines other than mounting machines. [Explanation of symbols]

[0073] 1: PCB production line 11~13: 1st to 3rd mounting machines (multiple machines) P: Substrate

Claims

1. 1. A method for optimizing production of substrates using a substrate production line including a plurality of machines that sequentially perform operations to produce the substrates, comprising: a first optimization step of performing an optimization process at a specified level to optimize a production program that controls the board production line so as to improve production efficiency of the boards; a determination step of determining whether or not there is a bottleneck machine whose production efficiency is lower than that of other machines when the boards are produced using the production program optimized by the first optimization step; a second optimization step of, if it is determined in the determination step that a bottleneck machine exists, raising the optimization level, which is the level at which optimization is pursued, only for the bottleneck machine and re-executing the optimization process of the production program.

2. 2. The method for optimizing a board production line according to claim 1, In the determination step, a cycle time, which is the work time per board, is obtained for each of the multiple machines, and the machine with the longest cycle time is identified as the bottleneck machine.

3. 3. The method for optimizing a board production line according to claim 2, In the determination step, an average cycle time, which is the average value of the cycle times of the plurality of machines, is compared with a longest cycle time, which is the cycle time of the machine with the longest cycle time, and if the longest cycle time is greater than the average cycle time by a predetermined percentage or more, the machine with the longest cycle time is identified as the bottleneck machine.

4. 3. The method for optimizing a board production line according to claim 2, the method further includes a balance adjustment step of performing line balance adjustment to allocate work of the bottleneck machine to other machines when it is determined in the determination step that the bottleneck machine exists; A method for optimizing a board production line, wherein the second optimization step is executed if the bottleneck machine still exists even after the balance adjustment step.

5. 5. The method for optimizing a board production line according to claim 4, further comprising a prediction step of predicting whether there is room for improving the cycle time of the bottleneck machine after the balancing step; A method for optimizing a board production line, wherein the second optimization step is executed only when it is determined in the prediction step that there is room for improvement.

6. The method for optimizing a board production line according to any one of claims 1 to 5, The method for optimizing a board production line further includes a presentation step of presenting to an operator information including each cycle time before and after performing the second optimization step.

7. A program for optimizing the production of substrates using a substrate production line including a plurality of machines that perform operations for producing substrates in sequence, a first optimization process that performs, at a specified level, an optimization process for optimizing a production program that controls the board production line so as to improve production efficiency of the boards; a determination process for determining whether or not there is a bottleneck machine whose production efficiency is lower than that of other machines when the boards are produced using the production program after the first optimization process; and a second optimization process in which, if it is determined in the determination process that a bottleneck machine exists, an optimization level at which optimization is pursued is raised only for the bottleneck machine, and the optimization process of the production program is re-executed.

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