JP2024053799A - Optimization method and optimization program for circuit board production line - Google Patents

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

The present invention relates to a technology for producing circuit boards using a production line that includes multiple machines that sequentially perform tasks to produce circuit boards.

When producing circuit boards using a circuit board production line that includes multiple machines, it is desirable to optimize the work of each machine as much as possible to improve the production efficiency of the circuit boards.

For example, the following Patent Document 1 discloses a device that optimizes the order in which components are mounted by each mounter and the allocation of components between 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 of each mounter, thereby improving the production efficiency of boards.

JP 2019-71478 A

There is a trade-off between the improvement in production efficiency achieved by optimization processing and the time required for said 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 possible. As a result, it is possible 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 placing emphasis on the result of improving production efficiency and allocating a lot of time to optimization processing, or not placing as much emphasis on the result and saving time on optimization processing.

The present invention has been made in consideration of the above circumstances, and aims to provide a method and program for optimizing a board production line that can simultaneously reduce the time required for optimization processing and improve production efficiency.

To solve the above problem, a method for optimizing a board production line according to one aspect of the present invention is a method for optimizing the production of boards using a board production line including a plurality of machines that perform tasks for producing 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 determination step of determining whether or not a bottleneck machine exists that has poor production efficiency compared to 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 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.

According to the present invention, a production program with the optimization level kept at a specified level is evaluated from the viewpoint of production efficiency, and if the evaluation reveals the presence of a bottleneck machine with relatively poor production efficiency, the optimization level of the bottleneck machine is raised, so that the target for which optimization is pursued can be limited to the bottleneck machine, and the production program can be updated to a new one with excellent production efficiency in a relatively short time. For example, if optimization is pursued without checking whether or not there is a bottleneck machine, it is necessary to raise the optimization level for all of the multiple machines in the board production line, and the time required for calculation may increase significantly. In contrast, in the present invention, the optimization level is raised only for the bottleneck machine that is deteriorating the production efficiency of the board production line, so that optimization can be pursued by focusing on the optimization target in the bottleneck machine, and the time required for optimization calculation can be shortened. The production program obtained by the calculation, that is, the new production program in which the optimization of the bottleneck machine is pursued, is likely to improve the efficiency of the work of the bottleneck machine and improve the production efficiency of the board. Therefore, according to the present invention, it is possible to improve the production efficiency of the board while shortening the time required for the optimization process.

Preferably, in the determination step, the 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.

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

Preferably, in the determination step, an average cycle time, which is the average value of the cycle times of the multiple 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.

In this manner, only if a machine has a significantly long cycle time can it be identified as a bottleneck machine and its optimization pursued.

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

In this embodiment, in cases where the cycle time can be improved by smoothing out the work distribution among multiple machines (line balancing), it is possible to pursue optimization of the bottleneck machine after making such improvements through smoothing. In other words, since line balancing takes precedence over raising the optimization level of the bottleneck machine, optimization of the bottleneck machine can be pursued only when a bottleneck machine still exists even after line balancing, and the production efficiency of boards can be improved rationally.

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.

In this manner, optimization of the bottleneck machine is pursued only when there is a possibility of improvement, thereby preventing unnecessary increases in calculation time.

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.

In this manner, the operator can easily understand the change in cycle time that occurs 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 of switching production programs.

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 for producing 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 determination process that determines whether or not a bottleneck machine exists that has a 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 determination 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.

This optimization program invention can achieve the same effects as the optimization method invention described above.

As described above, the present invention makes it possible to reduce the time required for optimization processing while improving production efficiency.

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; 4 is a flowchart showing the contents of a process performed by a program creation device. 3 is a subroutine showing details of the process of step S1 in FIG. 2 . FIG. 13 is a diagram showing the contents of initial conditions that are the basis for creating a production program. 13 is a graph showing the relationship between the upper limit calculation time and the optimization level, and the relationship between the upper limit number of trials and the optimization level. 11 is a table illustrating an example of cycle times of a plurality of mounting machines and the determination results of a bottleneck machine based thereon. 11 is a table showing an example of program information presented to an operator before the optimization level of a bottleneck machine is increased. 11 is a table showing an example of program information presented to an operator after the optimization level of a bottleneck machine has been increased.

[Configuration of the circuit board 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 an embodiment of the present invention is applied. The board production line 1 is a facility for producing a board P, and includes, in order from the upstream side in the conveying 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 to 13 is a machine that mounts electronic components (hereinafter simply referred to as components) on the upper surface of the board P. The board P produced through the work of each of the mounting machines 11 to 13 includes a raw board (printed wiring board) before components are mounted, and a plurality of components mounted on the upper surface of the raw board. In other words, the work target of each of the mounting machines 11 to 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 are not distinguished and are both referred to as 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 oven or inspection equipment may be located downstream of the third mounting machine 13.

The first to third mounting machines 11 to 13 are lined up in succession in the direction in which the board P is transported by the conveyor 22, which will be described later, so that they perform component mounting work on the board P in sequence. 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.

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

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

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 extending 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. For example, a ball screw mechanism can be used as the Y-axis movement mechanism 32 and the X-axis movement mechanism 33.

The head unit 23 can move in the Y direction in conjunction with the movement of the support frame 31, and can also move in the X direction along the support frame 31. The head unit 23 has multiple suction heads that can be raised and lowered to suck up and hold components to be mounted on the substrate P. The suction heads suck up and hold the components at the component removal position of the component supply device 25, move the components above the substrate P, and mount the components at the specified mounting positions on the substrate P.

All of the multiple component supply devices 25 are devices that supply components to be mounted on the substrate 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 areas on the +Y side and -Y side of the conveyor 22. The components supplied by the component supply devices 25 are small electronic components such as integrated circuits (ICs), transistors, resistors, capacitors, etc.

Each component supply device 25 includes a plurality of tape feeders 26 arranged in a line 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 can also be used.

The configuration of the first mounting machine 11 has been described above, but the configurations of the second mounting machine 12 and the third mounting machine 13 are similar.

[Control system]
Next, a control system of board production line 1 will be described. Board production line 1 is electrically connected to a production control device 41 and a program creation device 42. The production control device 41 is a device that controls the production of boards P performed by board production line 1 including first to third mounting machines 11 to 13. The program creation device 42 is a device that creates and updates the production program used by production control device 41. The production control device 41 and the program creation device 42 are composed of a microcomputer including a processor (CPU) that performs calculations and memories such as ROM and RAM.

The program creation device 42 is connected to the production control device 41 via a network LN, and creates and updates production programs and transmits them 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 programs acquired from the program creation device 42.

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 and a mouse. The display unit 44 is a display for presenting input/output data and the like for the program creation device 42 to the operator.

[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 here includes an optimization process of optimizing the production program so as to improve the production efficiency of board 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 increasing the optimization level. This will be described in detail below.

Figure 2 is a flowchart showing the contents of the processing performed by the program creation device 42. The processing shown in this flowchart is started by 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).

Figure 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 is started, the program creation device 42 reads predetermined basic data and optimization level (step S11). The basic data and optimization level are set in advance, for example, by the operator's operation via the input unit 43.

As shown in FIG. 4, the basic data includes board data, board handling conditions, and mounting machine data. The board data includes information such as the type of components to be mounted on the board P and the mounting coordinates of each component. The board handling conditions include information such as the transport speed of the board P. The mounting machine data includes information such as the position of the component supply device 25 (tape feeder 26) in each mounting machine 11-13, the mounting work position of the board P, and the movement speed of the head unit 23.

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 within the component supply device 25 of each mounting machine 11-13 (in other words, the order of the tape feeders 26), the order in which components are mounted by the head units 23 of each mounting machine 11-13, the division of work between each mounting machine 11-13 (allocation of which components are mounted by which mounting machine), etc.

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: the upper limit calculation time and the upper limit number of attempts. The upper limit calculation time is the upper limit of the time permitted to be consumed in generating one solution, and the upper limit number of attempts is the upper limit of the number of times that the generation of a solution and its evaluation are permitted to be repeated. As shown in Figure 5, the longer the upper limit calculation time, the higher the optimization level, and the higher the upper limit number of attempts, the higher the optimization level.

The upper limit calculation time and the upper limit number of trials are input in advance to the program creation device 42 by the operator operating the input unit 43. The upper limit calculation time and the upper limit number of trials can be set by directly inputting the numerical values, but can also be set by selecting one from a number of options such as "large", "medium", and "small". In the following, the set upper limit calculation time is T and the set upper limit number of trials is N.

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) previously set as described above. After that, 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 described above many times within the range of the upper limit calculation time T, and evaluates and compares the solution candidates obtained by each process from the viewpoint 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.

In detail, 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 be different. 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 a solution.

Next, the program creation device 42 determines whether the number of trials, which is the number of times a solution was generated in step S12, has reached the upper limit number of trials N loaded in step S11 (step S13).

If the result of 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 the 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.

On the other hand, if step S13 returns 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 perspective of production efficiency (step S14), and extracts the solution with the shortest cycle time from among them. The extracted solution is then output as a production program (step S15).

When the creation of the production program is completed through the above-mentioned processes, the flow proceeds to step S2 in FIG. 2. In this step S2, the program creation device 42 compares the cycle times of the first to third mounting machines 11 to 13 when mounting (producing) the board P according to the created production program, and extracts the mounting machine with the longest cycle time as the longest CT machine. The cycle time here is the work time consumed by each mounting machine 11 to 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 specified work position in the first mounting machine 11 to when 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, the multiple mounting machines may be extracted as the longest CT machines. In other words, the longest CT machine is not limited to one, but may be multiple.

The cycle times of the mounting machines 11 to 13 compared to each other to extract the longest CT machine may be values predicted by simulation or may be values measured. For example, depending on the urgency of the production of the board P, the production of the board P may be started immediately using the production program created in step S1, that is, before the processing of steps S7 and S8, which will be described later, which pursues the optimization of the production program, is performed. Alternatively, an operator who wishes to obtain a highly accurate cycle time may perform test production of the board P to measure the cycle time. In such a case, the cycle times of the mounting machines 11 to 13 according to the production program (step S1) can be obtained by actual measurement. Conversely, if there is no actual measurement value of such a cycle time, the extraction of the longest CT machine in step S2 is performed based on the predicted value of the cycle time obtained by simulation.

Then, the program creation device 42 judges whether or not 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, the program creation device 42 judges that the machine with the longest CT time corresponds to a bottleneck machine.

The predetermined ratio can be, for example, 5%. In this case, if the increment of the longest cycle time with respect to the average cycle time described above is 5% or more, the longest CT machine is treated as a bottleneck machine, and if the increment is less than 5%, the longest CT machine is not treated as a bottleneck machine. A specific example is shown in FIG. 6. In the example shown in this figure, 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 longest CT machine, with a longest cycle time of 30 seconds and an average cycle time of 27 seconds. In addition, the increment of the longest cycle time with respect to the average cycle time is about 11%, which is greater than 5%. Therefore, the second mounting machine 12, which is the longest CT machine, corresponds to a bottleneck machine.

If step S3 returns NO and it is confirmed that the machine with the longest CT is not a bottleneck machine, the program creation device 42 determines 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).

For example, as shown in FIG. 7, the program creation device 42 presents the operator via the display unit 44 with one row 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 mounting machine 11-13, and processing time. In FIG. 7, the estimated CT is an estimate obtained by simulating the cycle time, and the actual CT is an actual measurement 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, which pursue optimization, have not been performed, so "1" is displayed as the optimization level for each of the first mounting machines 11-13.

On the other hand, if step S3 returns YES and it is confirmed that the machine with the longest CT is a bottleneck machine, the program creation device 42 determines whether or not the line balance adjustment in step S5 described below has been performed (step S4).

If step S4 returns 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 process of 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 as the line balance adjustment. There are various ways to allocate work, but one possible method is to allocate the mounting work of some of the components that was to be performed by the bottleneck machine to other machines.

Once the line balance adjustment is performed in step S5, the process returns to step S2 and the subsequent steps are repeated. In other words, the presence or absence of a bottleneck machine is checked based on the cycle time of each mounting machine 11 to 13 after the line balance adjustment.

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

In other words, if the optimization level of the bottleneck machine has already been raised at least once (S7) at present, it is possible to predict whether there is room for improvement based on the trend of change in the cycle time of the bottleneck machine before and after this past optimization level raising. For example, if a past optimization level raising has resulted in a decrease in cycle time, it is possible to predict that there is still room for improvement, and if a past optimization level raising has hardly resulted in a decrease in cycle time, it is possible to predict that there is no more room for improvement. Note that if the optimization level of the bottleneck machine has not yet been raised even once (S7) at present, that is, if the past trend is unknown, it is sufficient to unconditionally predict that there is room for improvement.

Note that prediction of room for improvement is not limited to being based on past trends as described above. For example, if there is a production 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.

If the result of step S6 is NO and the prediction of room for improvement is confirmed to be negative, the program creation device 42 presents the results obtained so far to the operator (step S9).

On the other hand, if step S6 returns 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, changing only the optimization target of the bottleneck machine, and outputs the solution with the shortest cycle time among them as the new production program.

For example, if the second mounting machine 12 is a bottleneck machine as shown in FIG. 6, 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 order of the tape feeders 26) and the order in which components are mounted 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.

When the production program update is completed in steps S7 and S8, 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 mounting machine 11-13 after the program update (S2, S3), and if it is confirmed that a bottleneck machine still exists, a room for improvement in the cycle time is predicted to determine whether or not to further increase the optimization level of the bottleneck machine (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).

Figure 8 is a diagram showing an example of information presented to the operator when the optimization level is raised by step S9. In this figure, information on three types of production programs, No. 1 to 3, is presented as the result of raising the optimization level of the bottleneck machine twice. No. 1 is information on a production program obtained by performing line balance adjustment (S5) on the production program before the optimization level of the bottleneck machine is raised, that is, 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 program No. 1 are all marked as "1". No. 2 is information on a production program obtained by raising the optimization level of the second mounting machine 12, which is the bottleneck machine, by one step. In this program No. 2, the optimization level of the second mounting machine 12 is raised to "2" by raising the optimization level of the second mounting machine 12, while the optimization levels of the other mounting machines are maintained at "1". No. No. 3 is information on a production program obtained by raising the optimization level of the second mounting machine 12 (bottleneck machine) by one more step. 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 level of the other mounting machines is maintained at "1". Also, taking into consideration the cycle time values shown in FIG. 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.

In the flowchart of FIG. 2 described above, the process of step S1 corresponds to the "first optimization step" or "first optimization process" in the present invention, the processes of steps S2 and S3 correspond to the "judgment step" or "judgment process" in the present invention, the process of step S5 corresponds to the "balance adjustment step" in the present invention, the process of step S6 corresponds to the "prediction step" in the present invention, the processes of steps S7 and S8 correspond to the "second optimization step" or "second optimization process" in the present invention, and the process of step S9 corresponds to the "presentation step" in the present invention.

[Effects, etc.]
As explained above, in this embodiment, after a production program (S1) is created at a specified optimization level, it is determined whether or not there is a bottleneck machine with a relatively long cycle time (S2, S3), and if the presence of a bottleneck machine is confirmed by this determination, the optimization level is raised only for that bottleneck machine and the optimization process is re-executed (S7, S8). This configuration has the advantage that the production efficiency of the substrate P can be improved while shortening the time required for the optimization process.

That is, in this embodiment, the production program with the optimization level kept at a specified level is evaluated from the viewpoint of cycle time (production efficiency), and if the evaluation reveals the presence of a bottleneck machine with a relatively long cycle time (poor production efficiency), the optimization level of the bottleneck machine is raised, so that the target for which optimization is pursued can be limited to the bottleneck machine, and it is possible to update to a new production program with excellent production efficiency in a relatively short time. For example, if optimization is pursued without checking whether or not there is a bottleneck machine, it is necessary to raise the optimization level for all of the first to third mounting machines 11 to 13, and the time required for calculation may increase significantly. 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, so that optimization can be pursued by focusing on the optimization target (component placement, mounting order, etc.) in the bottleneck machine, and the time required for optimization calculation can be shortened. The production program obtained by this calculation, that is, the new production program in which the optimization of the bottleneck machine is pursued, is likely to improve the efficiency of the work of the bottleneck machine 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 substrate P while shortening the time required for optimization processing.

In addition, 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 (e.g., 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.

In addition, in this embodiment, when the presence of a bottleneck machine is confirmed, a line balance adjustment is first performed to allocate the work of the bottleneck machine to other machines, and if a bottleneck machine still exists after the line balance adjustment, the optimization level of the bottleneck machine is raised. With this configuration, in cases where the cycle time can be improved by smoothing out the work distribution (line balance adjustment) between 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 balance adjustment 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 the line balance adjustment, and the production efficiency of the board P can be rationally improved.

In addition, in this embodiment, after the above-mentioned line balance adjustment, a prediction is made as to whether there is room for improvement in 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, so it is possible to prevent unnecessary increases in calculation time.

In addition, in this embodiment, when a process is performed to update a production program by raising the optimization level of a bottleneck machine, 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 occurs 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.

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

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, the 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 tasks 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.

1: Board production line 11-13: 1st to 3rd mounting machines (multiple machines)
P: Substrate

Claims (7)

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 for controlling the board production line so as to improve production efficiency of the board;
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 board is produced using the production program optimized by the first optimization step;
a second optimization step of, when it is determined in the determination step that a bottleneck machine exists, raising an optimization level, which is a level at which optimization is pursued, only for the bottleneck machine and re-executing the optimization process of the production program. 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 one board, is obtained for each of the multiple machines, and the machine with the longest cycle time is identified as the bottleneck machine, in this method for optimizing a board production line. 3. The method for optimizing a board production line according to claim 2,
A method for optimizing a board production line, in which the determination step compares an average cycle time, which is the average value of the cycle times of the multiple machines, 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. 3. The method for optimizing a board production line according to claim 2,
a balance adjustment step of performing a line balance adjustment to allocate the 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 a bottleneck machine still exists even after the balance adjustment step. 5. The method for optimizing a board production line according to claim 4,
The method further includes a prediction step of predicting whether there is room for improving a 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 by the prediction step that there is room for improvement. 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. A program for optimizing the production of substrates using a substrate production line including a plurality of machines that sequentially perform operations for producing substrates, comprising:
a first optimization process that optimizes a production program for controlling the board production line so as to improve production efficiency of the boards at a specified level;
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 for, when it is determined in the judgment process that a bottleneck machine exists, raising an optimization level, which is a level at which optimization is pursued, only for the bottleneck machine and re-executing the optimization process of the production program.