JP7694352B2 - Production planning system and production planning method - Google Patents

Description

This disclosure relates to a production planning system and a production planning method.

Conventionally, there is a technology for efficient production on a production line where multiple areas where processes are performed are arranged on the line (for example, Patent Document 1). Patent Document 1 discloses a technology for arranging a display means used for an inspection process in the area of a surplus process that has time left over when the time required for the work is subtracted from the takt time among multiple processes.

JP 2013-210822 A

However, when a malfunction occurs in equipment used on a production line, it becomes necessary to carry out maintenance work on the equipment. If the malfunctioning equipment is equipment used in the above-mentioned redundant process, the maintenance work can be carried out using the redundant time. However, there are cases where the malfunctioning equipment is not equipment used in the above-mentioned redundant process, or where the maintenance work cannot be completed within the redundant time. In such cases, it becomes necessary to stop the production line to carry out the maintenance work, and there is a risk that the target production volume cannot be produced.

The present disclosure can be realized in the following forms.
According to one embodiment of the present disclosure, a production planning system is provided, which plans a production plan for a production line, the production plan including a takt time calculated by dividing the operation time of the production line by a target production volume, includes a determination unit that determines whether a detection value indicating the performance of equipment used in the production line exceeds a reference value that is a predicted value of the detection value at a reference time obtained by subtracting a grace period from a predicted time when maintenance work of the equipment is predicted to be required, an acquisition unit that acquires a maintenance work time required for the maintenance work when the determination unit determines that the reference value has been exceeded, and a reduction time of the takt time to generate the maintenance work time within the grace period using the grace period and the maintenance work time. a calculation unit that calculates, when a reduced takt time obtained by subtracting the reduced time from the takt time is equal to or less than a cycle time, a time obtained by subtracting the cycle time from the takt time as the reduced time; and a modification unit that modifies the production plan, wherein, when the reduced takt time is longer than the cycle time, the modification unit modifies the previous production plan to the production plan using the reduced takt time, and when the reduced takt time is equal to or less than the cycle time, the modification unit modifies the previous production plan to the production plan using the reduced takt time which includes a reduction in the target production quantity.

(1) According to one embodiment of the present disclosure, a production planning system is provided. The production planning system is provided with: a production plan for a production line, which is a production plan including a takt time calculated by dividing the operation time of the production line by a target production number; a determination unit that determines whether a detection value indicating the performance of equipment used in the production line exceeds a reference value that is a predicted value of the detection value at a reference time obtained by subtracting a grace time from a predicted time when maintenance work of the equipment is predicted to be required; an acquisition unit that acquires a maintenance work time required for the maintenance work when the determination unit determines that the detection value has exceeded the reference value; a calculation unit that calculates a shortening time of the takt time to generate the maintenance work time within the grace time using the grace time and the maintenance work time; and a change unit that changes the previous production plan to the production plan using a shortened takt time obtained by subtracting the shortened time from the takt time. According to this embodiment, by predicting maintenance work in advance and shortening the takt time when maintenance work is required, it is possible to perform the maintenance work without reducing the target production number.
(2) In the production planning system of the above aspect, the change unit may change the production plan from the previous production plan to the production plan including a reduction in the target production volume when the reduced takt time is shorter than the cycle time. According to this aspect, when the reduced takt time is shorter than the cycle time which is the actual production time per unit, the production plan can be changed to the production plan including a reduction in the target production volume.
(3) In the production planning system of the above aspect, the production line may include a plurality of pieces of equipment, the grace time and the maintenance work time may be predetermined for each of the plurality of pieces of equipment, and when the determination unit determines that the detection value for each of the plurality of pieces of equipment has exceeded the reference value, the calculation unit may calculate the shortened time using the grace time of the piece of equipment having the shortest grace time among the plurality of pieces of equipment whose detection value has been determined to have exceeded the reference value and a longest maintenance work time which is the maintenance work time of the piece of equipment whose maintenance work time is the longest, and the change unit may set a stop time of the production line for performing the maintenance work for the plurality of pieces of equipment within the longest maintenance work time. According to this aspect, a plurality of maintenance works can be performed during a stop time of the production line, and therefore the maintenance work can be performed efficiently.
(4) In the production planning system of the above aspect, the determination unit may be capable of communicating with a storage unit that stores prediction data in which the limit value, which is the detection value at the prediction time, the reference value, and the equipment are associated with each other, and the determination unit may make a determination using the reference value of the prediction data. According to this aspect, it is possible to determine whether or not the reference value has been exceeded using the prediction data.
(5) The production planning system of the above aspect may further include an updating unit that updates the reference value to move away from the limit value so as to lengthen the grace time when the reduced takt time is shorter than the cycle time. According to this aspect, in the next maintenance work, an adjustment to reduce the takt time can be made early, so that the possibility of performing the maintenance work without reducing the target production volume can be increased.
(6) The production planning system of the above aspect may further include a setting unit that sets the grace time to a longer value as the maintenance work time is longer. According to this aspect, even when the maintenance work time is long, by setting the grace time to a longer value, it is possible to increase the possibility that the maintenance work time can be generated by shortening the takt time without changing the target production volume.
The present disclosure may be realized in various forms of a production planning system, for example, a production planning method, etc.

Schematic diagram of a production line and production planning system. FIG. 1 is a block diagram showing a configuration of a production planning system. FIG. 1 is a block diagram showing the configuration of a belt conveyor facility. FIG. 13 is a flowchart of a production planning process. 13 is a flowchart of a process for calculating a time reduction. FIG. 13 is a diagram for explaining a changed production plan. 13 is a flowchart of a production planning process according to a second embodiment. FIG.

A. First embodiment:
FIG. 1 is a schematic diagram of a production line 10 and a production planning system 20. FIG. 2 is a block diagram showing the configuration of the production planning system 20. FIG. 3 is a block diagram showing the configuration of a facility F1, which is a belt conveyor. As shown in FIG. 1, the production line 10 performs production using a production plan 81 (FIG. 2) created by the production planning system 20. In the production line 10, a plurality of areas for performing each process are arranged on the line. A product W is transported to each process area in sequence, and each process is performed. In the production line 10, a plurality of facilities F are used. Specifically, the facilities F are a belt conveyor for transporting the product W, devices and workers such as robots and tools that process and assemble the product W, and devices and workers that inspect the product. In this embodiment, each of the plurality of facilities F is given an identification number. When each of the plurality of facilities is to be distinguished from each other, the identification number is added after the facility F. For example, the facility F1 is a facility F with an identification number of "1". In this embodiment, the production line 10 includes s pieces of equipment F from equipment F1 to equipment Fs. Equipment F1 is a belt conveyor. Equipment F2 and equipment F4 are workers. Equipment F3, equipment F5, and equipment Fs are devices. Areas where each process is performed include areas where workers are stationed and unmanned areas where no workers are stationed and only devices are stationed. In this embodiment, the production line 10 includes n processes from process 1 to process n.

The production planning system 20 formulates a production plan 81. The production planning system 20 sets a target production number for a unit production period in order to produce a target total production number set, for example, using the number of orders, during the production period. The production period is, for example, one month. The unit production period is, for example, one week or one day. The production planning system 20 also calculates the takt time by dividing the operation time in the unit production period by the target production number in the unit production period. If the calculated takt time is shorter than the cycle time, the production planning system 20 changes the production plan 81 to one in which the target production number is reduced so that the takt time is equal to or longer than the cycle time, and updates the production plan 81. Here, the cycle time is a time calculated by dividing the operation time by the actual production number. The value of the cycle time is the actual value of the past cycle time. The value of the cycle time varies depending on, for example, the proficiency of the workers. The unit of the takt time and the cycle time is both "seconds". The process in which the production planning system 20 creates the production plan 81, as described above, is also referred to as the planning step.

The production planning system 20 is realized by a PC. As shown in FIG. 2, the production planning system 20 includes a control unit 21, a display 24, and a keyboard 25. The control unit 21 has a CPU 22 and a memory 23 as a storage unit. The CPU 22 also has a judgment unit 31, an acquisition unit 32, a calculation unit 33, and a change unit 34 as functional units. Each functional unit such as the judgment unit 31 is realized by executing a program stored in the memory 23. As will be described in detail later, the judgment unit 31 uses the equipment data 82 to determine whether or not a detection value indicating the performance of the equipment F exceeds a reference value, which is a predicted value of the detection value at a reference time t1 obtained by subtracting a grace period from a predicted time t2 at which maintenance work on the equipment F is predicted to be required. The acquisition unit 32 acquires the maintenance work time required for the maintenance work. The calculation unit 33 calculates the shortening time of the takt time to generate the maintenance work time within the grace period. The change unit 34 changes the previous production plan 81 to a production plan 81 that uses a reduced takt time obtained by subtracting the reduced time from the takt time. The memory 23 stores the production plan 81, equipment data 82, and prediction data 83. The production plan 81 is a production plan 81 created by the production planning system 20. The equipment data 82 and the prediction data 83 are used to predict maintenance work, etc. The equipment data 82 is data that indicates changes over time in detection values that indicate the performance of equipment F. The display 24 displays information. The keyboard 25 accepts input of information.

The production planning system 20 is communicatively connected to the equipment F, excluding the workers, that is, the equipment F, which is a device, among the multiple equipment F. With reference to FIG. 3, the equipment F1, which is a belt conveyor, will be described as an example. The equipment F1 includes a communication unit 50, a drive unit 51, rollers 52, and a detection sensor 53. The communication unit 50 communicates with the production planning system 20. The rollers 52 rotate a conveyor belt (not shown). The drive unit 51 drives the rollers 52. The detection sensor 53 is a sensor for detecting the friction coefficient between the rollers 52 and the conveyor belt. The communication unit 50 is communicatively connected to the drive unit 51 and the detection sensor 53. The drive unit 51 controls the rollers 52 so that the conveying time between the areas of each process is the target conveying time according to the production plan 81 transmitted from the production planning system 20 via the communication unit 50. The detection sensor 53 transmits the detection value of the detection sensor 53, which indicates the friction coefficient, to the production planning system 20 via the communication unit 50. The information communicated between the production planning system 20 and the equipment F depends on the type of equipment F. For example, if the equipment F is a screw tightening tool, the torque value during screw tightening is transmitted as the detected value. For example, if the equipment F is a welding robot, the current value during welding is transmitted as the detected value.

The detection value transmitted from equipment F to production planning system 20 indicates the performance of equipment F and is used as an index for carrying out maintenance work on equipment F. For example, when the detection value indicating the friction coefficient of equipment F1 becomes larger than a limit value described below, maintenance work such as applying oil is carried out.

Figure 4 is a diagram explaining equipment data 82 for equipment F1. The horizontal axis of Figure 4 is time, and the vertical axis is a detection value indicating the friction coefficient that indexes the performance of equipment F1. Equipment data 82 is time-series data in which the accumulated operating time of equipment F since the previous maintenance work was performed is associated with the detection value. Equipment data 82 is stored in memory 23 for each equipment F. Data transmission from production planning system 20 is performed continuously. Specifically, data transmission is performed during the period when equipment F is operating, for example, at predetermined time intervals. When control unit 21 receives the detection value, it adds the received detection value to equipment data 82 and updates equipment data 82.

For each piece of equipment F, a limit value for performing maintenance work and a reference value for predicting maintenance work are set in advance. The limit value is used to determine whether or not maintenance work needs to be performed immediately. Specifically, if the detection value exceeds the limit value, for example, an alarm provided in equipment F sounds and the operation of equipment F is stopped. In this case, after the maintenance work is performed by an operator, the operation of equipment F is resumed.

As described above, if the detection value exceeds the limit value and the operation of equipment F is stopped, the production line 10 is stopped and production according to the production plan 81 is not carried out. Therefore, in this embodiment, a reference value is set, which is the predicted value of the detection value at reference time t1, which is obtained by subtracting a grace period from the predicted time t2 at which maintenance work on equipment F is predicted to be necessary, and maintenance work is predicted by comparing the detection value with the reference value. Furthermore, by scheduling maintenance work in advance, the takt time of the production plan 81 is changed in advance. This makes it possible to produce the target production quantity.

Data in which a limit value, a reference value, and a grace period are set for each piece of equipment F is the prediction data 83. The limit value is a detection value indicating the performance of equipment F at prediction time t2. The reference value is a prediction of the detection value at reference time t1. Typically, the actual detection value at reference time t1 is set as the reference value. This makes it possible to predict that when the detection value exceeds the reference value, the detection value will exceed the limit value after the grace period has elapsed. The prediction data 83 is created using past equipment data 82. Depending on the type of equipment F, the worse the performance, the larger or smaller the detection value will be. For example, in the case of equipment F1, the higher the detection value indicating the friction coefficient, the lower the performance.

Figure 5 is a flowchart of the production planning process that realizes the production planning method. Figure 6 is a flowchart of the time reduction calculation process. Figure 7 is a diagram explaining the production plan 81 after the change. When the production planning system 20 accepts the execution of the production planning process, it executes the production planning process.

In this embodiment, the production planning process is performed for facility F1. The judgment unit 31 refers to the forecast data 83 and assigns the reference value of facility F1 to variable B (step S12). The judgment unit 31 assigns the latest detection value of facility data 82 to variable V (step S14). Facility F is a facility F whose detection value increases as performance deteriorates, so the judgment unit 31 judges whether variable V is greater than the absolute value of variable B (step S16). If it is determined that variable V is not greater than the absolute value of variable B, that is, variable V is equal to or less than the absolute value of variable B (step S16: NO), the judgment unit 31 repeatedly executes steps S14 and S16 at a predetermined time, for example every few minutes, until it is determined that variable V is greater than the absolute value of variable B.

When it is determined that variable V is greater than the absolute value of variable B (step S16: YES), the change unit 34 refers to the production plan 81 and assigns the takt time to variable T and the cycle time to variable C (step S30). When it is determined that variable V is greater than the absolute value of variable B, that is, when it is determined that the performance of equipment F1 has deteriorated because the detection value indicating the performance of equipment F1 has exceeded the reference value. Step S16 is also called the judgment step. The takt time and cycle time that are assigned are the times set in the production plan 81. When it is determined that variable V is greater than the absolute value of variable B, it is when maintenance work on equipment F1 needs to be performed after the grace period has elapsed.

The change unit 34 determines whether the variable T is greater than the variable C (step S32). If it is determined that the variable T is not greater than the variable C, that is, the variable T is equal to or less than the variable C (step S32: NO), the change unit 34 changes the previous production plan 81 to a production plan 81 that reduces the target production volume and incorporates the stoppage of the production line (step S70). If the variable T is equal to or less than the variable C, there is no room to reduce the takt time, so the target production volume is reduced and the operating time is shortened to generate time to perform maintenance work. The modified production plan is sent to the facility F.

As shown in FIG. 7, specifically, the stop of the production line 10 is planned at the end of the grace period. If the end of the grace period indicated by the arrow is the end of the operation time of the third operating day, the maintenance work is planned at the end of the operation time of the third operating day. Note that FIG. 7 shows a case where the unit production period is one week and step S70 is performed at the start of operation on the second operating day. On the day when the maintenance work is performed, for example, a message that the production line 10 will be stopped is displayed on the display 24. This allows the worker to know that the production line 10 will be stopped. At the time when the maintenance work is scheduled, the transportation of the product W by the equipment F1 is stopped. Then, the worker performs the maintenance work on the equipment F1. In this case, although it is necessary to reduce the target production number, in order to compensate for the reduced production number, it is possible to take measures early, such as increasing the operation time after the grace period has elapsed. After executing step S70, the control unit 21 ends this processing routine.

As shown in FIG. 5, when the change unit 34 determines that the variable T is greater than the variable C (step S32: YES), the acquisition unit 32 assigns the maintenance work time of the equipment F1 acquired from the prediction data 83 to the variable M, and assigns the grace time acquired from the prediction data 83 to the variable P (step S38). Step S38 is also called the acquisition step. This is because when the variable T is greater than the variable C, there is room to shorten the takt time, and therefore a shortened time calculation process is performed.

The calculation unit 33 performs a time reduction calculation process to calculate the amount of takt time reduction required to perform the maintenance work time (step S40). Step S40 is also referred to as the calculation step. As shown in FIG. 6, the calculation unit 33 assigns zero to a variable t indicating the time reduction [seconds] (step S50). The calculation unit 33 increments the variable t (step S52). The calculation unit 33 calculates a total time b indicating the total amount of time reduction in the period until the grace period has elapsed (step S54). Specifically, the total time b is calculated by multiplying the variable t by the target production volume in the grace period.

The calculation unit 33 judges whether the total time b is greater than the variable M indicating the maintenance work time (step S56). If it is judged that the total time b is not greater than the variable M, that is, the total time b is equal to or less than the variable M (step S56: NO), the calculation unit 33 judges whether the value obtained by subtracting the variable C from the variable T is equal to the variable t (step S58). If it is judged that the value obtained by subtracting the variable C from the variable T is not equal to the variable t (step S58: NO), there is room for further shortening of the takt time, so the calculation unit 33 proceeds to step S52. Then, the calculation unit 33 increments t until it judges that the total time b is greater than the variable M or judges that the value obtained by subtracting the variable C from the variable T is equal to the variable t (step S52), and executes the processing steps from step S54 onwards.

When the calculation unit 33 determines that the total time b is greater than the variable M (step S56: YES), it returns the values of the total time b and the variable t (step S60). The value of the variable t when it is determined that the total time b is greater than the variable M is the shortened time of the takt time to generate the maintenance work time within the grace period. This case refers to a case where the maintenance work time can be generated without reducing the target production volume by shortening the takt time.

When the calculation unit 33 determines that the value obtained by subtracting the variable C from the variable T is equal to the variable t (step S58: YES), it returns the total time b and the value of the variable t (step S60). This case refers to a case where the maintenance work time cannot be generated without reducing the target production volume even if the takt time is shortened to the cycle time.

As shown in FIG. 5, the change unit 34 judges whether the returned value of the total time b is greater than the variable M (step S42). If it is judged that the total time b is greater than the variable M (step S42: YES), the change unit 34 changes the current takt time to a takt time obtained by subtracting the variable t indicating the shortened time from the current takt time, and changes the production plan 81 to one incorporating a maintenance work plan (step S72). The takt time obtained by subtracting the variable t from the current takt time in a case where the takt time can be shortened to incorporate maintenance work while maintaining the target production volume is also called the shortened takt time. That is, in step S72, the change unit 34 changes the current production plan 81 to a production plan 81 using the shortened takt time. The time for performing maintenance work is generated by shortening the takt time and shortening the operating time. Step S72 is also called a change step. To generate the maintenance work time, in step S70, the target production volume is reduced to shorten the operating time, whereas in step S72, the target production volume is not changed and the takt time is shortened to shorten the operating time. In this way, by shortening the takt time, maintenance work can be performed within the grace period while maintaining the target production volume.

The modified production plan is sent to equipment F. This shortens the time interval at which products W are transported from the previous process area to the process area. After executing step S72, the control unit 21 ends this processing routine.

If it is determined that the total time b is not greater than the variable M, that is, the total time b is equal to or less than the variable M (step S42: NO), the change unit 34 reduces the target production number, changes the current takt time to a takt time obtained by subtracting the variable t indicating the shortened time from the current takt time, and changes the production plan 81 to one incorporating a maintenance work plan (step S74). This case is when the shortened takt time is shorter than the cycle time. In other words, in order to generate a maintenance work time while maintaining the target production number, it is necessary to make the takt time shorter than the cycle time. However, since the takt time cannot be set shorter than the cycle time, the target production number is reduced and the maintenance work is incorporated into the plan. Step S74 is the same as step S72 in that the takt time is shortened, but is different in that the target production number is reduced. Also, step S74 is the same as step S70 in that the target production number is reduced, but is different in that the takt time is shortened. By changing the production plan 81 in step S74, the target production volume will decrease, as in step S70, but measures can be taken early to compensate for the decreased production volume. In addition, by shortening the takt time, the decrease in the target production volume can be made smaller than if the takt time was not shortened. After executing step S74, the control unit 21 ends this processing routine.

According to the first embodiment described above, the production planning system 20 includes a judgment unit 31, an acquisition unit 32, a calculation unit 33, and a change unit 34. The judgment unit 31 judges whether the detected value exceeds a reference value, which is a predicted value of the detected value at the reference time t1 obtained by subtracting the grace time from the predicted time t2, by comparing the variable V indicating the detected value with the absolute value of the variable B indicating the reference value (step S16). If it is judged that the variable V is greater than the absolute value of the variable B, that is, if it is judged that the detected value exceeds the reference value, the acquisition unit 32 acquires the maintenance work time and assigns it to the variable M (step S38). The calculation unit 33 uses the variable M indicating the maintenance work time to execute a reduction time calculation process (step S40) to calculate a variable t indicating a reduction time of the takt time for generating the maintenance work time within the grace time. The change unit 34 changes the current takt time to a production plan 81 using a reduced takt time obtained by subtracting the reduced time from the current takt time (step S72). This allows maintenance work to be predicted in advance, and if maintenance work is necessary, it can be performed without changing the target production volume by shortening the takt time.

In addition, if the shortened takt time, which is obtained by subtracting the variable t indicating the shortened time from the takt time, is shorter than the cycle time, the change unit 34 changes the production plan 81 to one that includes a reduction in the target production volume (step S74). As a result, if the shortened takt time is shorter than the cycle time, it is possible to change the production plan 81 to one that includes a reduction in the target production volume.

The determination unit 31 also uses the reference value set in the prediction data 83 to determine whether the variable V indicating the detection value is greater than the variable B indicating the reference value (step S16). This allows the determination unit 31 to use the prediction data 83 to determine whether the detection value has exceeded the reference value.

B. Second embodiment:
8 is a flowchart of the production planning process according to the second embodiment. In the first embodiment, the production planning process is performed for one facility F, but in this embodiment, the production planning process is performed for multiple facilities F. The same processing steps as in the first embodiment are given the same reference numerals, and detailed explanations are omitted as appropriate.

When the production planning system 20 accepts the execution of the production planning process, it executes the production planning process. The production planning process is performed, for example, every day.

The judgment unit 31 assigns the initial value "1" to the variable m, and sets facility Fm, which is facility F with facility ID "m", as the target for subsequent steps S13 to S17 (step S10). The judgment unit 31 refers to the prediction data 83, and assigns the reference value of facility Fm to variable B (step S13). The judgment unit 31 assigns the latest detection value of the facility data 82 to variable V (step S15).

The judgment unit 31 judges whether the detected value of the variable V exceeds the reference value (step S17). As described above, whether the value indicating the performance becomes larger or smaller as the performance becomes worse varies depending on the equipment F. In the case of equipment F, such as equipment F1, in which the value indicating the performance becomes larger as the performance deteriorates, in step S17, similar to step S16 according to the first embodiment, it is judged whether the variable V is larger than the absolute value of the variable B. If it is judged that the variable V is larger than the absolute value of the variable B, it is judged that the detected value has exceeded the reference value. On the other hand, if it is judged that the variable V is not larger than the absolute value of the variable B, it is judged that the detected value has not exceeded the reference value. In the case of equipment F, in which the value indicating the performance becomes smaller as the performance deteriorates, in step S18, it is judged whether the variable V is smaller than the absolute value of the variable B. If it is judged that the variable V is smaller than the absolute value of the variable B, it is judged that the detected value has exceeded the reference value. On the other hand, if it is judged that the variable V is not smaller than the absolute value of the variable B, it is judged that the detected value has not exceeded the reference value.

If it is determined that the detection value exceeds the reference value (step S17: YES), the judgment unit 31 stores the target facility ID, i.e., the value of variable m, in the memory 23 (step S20). On the other hand, if it is determined that the detection value of variable V does not exceed the reference value (step S17: NO), the judgment unit 31 proceeds to step S22 without storing the target facility ID in the memory 23.

The judgment unit 31 increments the variable m (step S22) and judges whether the variable m is greater than the variable s indicating the total number of facilities F (step S24). If it is judged that the variable m is not greater than the variable s, that is, the variable m is equal to or less than the variable s (step S24: NO), the judgment unit 31 proceeds to step S10 to judge the next facility F. If it is judged that the variable m is greater than the variable s (step S24: YES), the judgment for all facilities F has been completed, and the control unit 21 proceeds to step S30.

The change unit 34 assigns the current takt time to variable T and assigns the cycle time to variable C (step S30). The change unit 34 determines whether variable T is greater than variable C (step S32). If it is determined that variable T is not greater than variable C (step S32: NO), the change unit 34 changes the production plan 81 (step S70) in the same manner as in the first embodiment. After executing step S70, the control unit 21 ends this processing routine.

If the change unit 34 determines that the variable T is greater than the variable C (step S32: YES), the acquisition unit 32 refers to the prediction data 83, extracts the grace period associated with the stored equipment ID, and acquires the shortest grace period (step S34). The change unit 34 refers to the prediction data 83, extracts the maintenance work time associated with the stored equipment ID, and acquires the longest maintenance work time, which is the longest maintenance work time (step S36).

Figure 9 is a diagram explaining the predicted data 83. The predicted data 83 is a database in which equipment IDs, grace periods, and maintenance work times are associated with each other. The predicted data 83 is created using past maintenance work results. For example, when the detection value of equipment F1 exceeds the reference value, it is predicted that the detection value will exceed the limit value after 140 hours have passed. The maintenance work for equipment F1 is 0.5 hours.

The acquisition unit 32 assigns the acquired longest maintenance work time to the variable M, and assigns the acquired shortest grace time to the variable P (step S39). The calculation unit 33 performs a shortened time calculation process (step S40). In the shortened time calculation process according to this embodiment, in step S54 (FIG. 6), the total time b is calculated using the target production number in the shortest grace time acquired in step S36 (FIG. 8). In addition, in step S56 (FIG. 6), a judgment is made using the longest maintenance work time acquired in step S34 (FIG. 8). This allows the maintenance work to be performed simultaneously for the multiple pieces of equipment F when maintenance work is required. For example, when it is determined that the equipment F1, the equipment F3, and the equipment F5 shown in FIG. 9 have reached the reference time t1, the maintenance work time of 1.5 hours, which is the longest maintenance work time, is generated, and maintenance work for the three pieces of equipment F can be performed by stopping the production line 10 once. This reduces the frequency of stoppages of the production line 10 compared to performing maintenance work at the end of each grace period for multiple pieces of equipment F.

The change unit 34 judges whether the returned value of the total time b is greater than the variable M indicating the maintenance work time (step S42). If it is judged that the total time b is greater than the variable M (step S42: YES), the change unit 34 changes to the production plan 81 as in the first embodiment (step S72). Specifically, the change unit 34 sets the stop time of the production line 10 to perform maintenance work on multiple pieces of equipment F within the longest maintenance work time. If it is judged that the total time b is not greater than the variable M (step S42: NO), the change unit 34 changes to the production plan 81 as in the first embodiment (step S74). After executing steps S72 and S74, the control unit 21 ends this processing routine.

According to the second embodiment described above, in step S40, the calculation unit 33 calculates the shortened time using the grace period of the equipment F with the shortest grace period among the multiple pieces of equipment F determined to require maintenance work and the maintenance work time of the equipment F with the longest maintenance work time. This allows maintenance work to be performed on multiple pieces of equipment F at the same time, making it possible to carry out maintenance work efficiently.

C. Other embodiments:
(C1) The control unit 21 may further include an update unit as a functional unit. When the reduced takt time is shorter than the cycle time, the update unit updates the forecast data 83 so that the reference value is moved away from the limit value so that the grace period is longer. Specifically, after execution of step S74 of the production planning process according to the first embodiment, a processing step (update step) may be inserted in which the update unit updates the forecast data 83 so that the reference value is moved away from the limit value so that the grace period is longer. The reduced takt time is shorter than the cycle time when the maintenance work time cannot be generated even if the takt time is reduced to the same as the cycle time. In this case, by setting the reference value so that the grace period is longer, the next production planning process can be adjusted to reduce the takt time earlier, and therefore the possibility of performing the maintenance work without changing the target production number can be increased.

(C2) The control unit 21 may further include a setting unit as a functional unit. The setting unit sets a longer grace period in the prediction data 83 the longer the maintenance work time for equipment F. In this way, even if the maintenance work time is long, by setting a longer grace period, it is possible to generate maintenance work time by shortening the takt time.

(C3) As described above, the detection value is a detection value indicating the friction coefficient, a detection value indicating the torque value, etc. The time when maintenance work will be performed can also be predicted using the accumulated time of operation since the previous maintenance work and the accumulated value of the production number. Therefore, the accumulated time of operation of equipment F since the previous maintenance work was performed and the accumulated value of the production number may be used as the detection value. In other words, the detection value may be the accumulated time of operation and the accumulated value of the production number detected by a timer.

(C4) In step S70 of the production planning process according to the first embodiment, the production plan 81 is changed to one in which maintenance work is performed at the end of the grace period. The time when maintenance work is performed is not limited to the end of the grace period. For example, if the grace period ends in the middle of the operating hours of a day, the production plan 81 may be changed to one in which maintenance work is performed at the end of the operating hours of the previous day. This makes it possible to avoid interruptions to perform maintenance work during the operating hours of a day.

(C5) In the first embodiment, if it is determined that the total time b is not greater than the variable M (step S42: NO), the change unit 34 reduces the target production number, changes it to a value obtained by subtracting the variable t from the current takt time, and changes it to a production plan 81 that incorporates a maintenance work plan (step S74). Alternatively, the change unit 34 may reduce the target production number without shortening the takt time, and change it to a production plan 81 that incorporates a maintenance work plan. This makes it possible to change to a production plan 81 that has enough leeway to avoid changing the target production number even in the event of a sudden stoppage of the production line 10.

(C6) In the first embodiment, the equipment data 82 and the forecast data 83 are stored in the memory 23 of the production planning system 20. The device in which the equipment data 82 and the forecast data 83 are stored is not limited to the production planning system 20. For example, the equipment data 82 and the forecast data 83 may be stored in a server that can communicate with the production planning system 20. Furthermore, each piece of equipment F may transmit a signal to the production planning system 20 when the detection value exceeds a reference value, and the production planning system 20 may determine that the detection value has exceeded the reference value when it receives the signal.

The present disclosure is not limited to the above-described embodiments, and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features of the embodiments corresponding to the technical features in each form described in the Summary of the Invention column can be replaced or combined as appropriate to solve some or all of the above-described problems or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate.

10...production line, 20...production planning system, 21...control unit, 22...CPU, 23...memory, 24...display, 25...keyboard, 31...judgment unit, 32...acquisition unit, 33...calculation unit, 34...change unit, 50...communication unit, 51...drive unit, 52...roller, 53...detection sensor, 81...production plan, 82...equipment data, 83...prediction data, F, F1 to F5, Fs...equipment, W...product

Claims (5)

A production planning system, comprising:
the production planning system creates a production plan for a production line, the production plan including a takt time calculated by dividing an operating time of the production line by a target production volume;
a judgment unit that judges whether a detection value indicating a performance of a facility used in the production line exceeds a reference value that is a predicted value of the detection value at a reference time obtained by subtracting a grace period from a predicted time when maintenance work for the facility is predicted to be required;
an acquisition unit that acquires a maintenance work time required for the maintenance work when the determination unit determines that the reference value has been exceeded;
a calculation unit that calculates a shortening time of the takt time for generating the maintenance work time within the grace time by using the grace time and the maintenance work time, and when a shortened takt time obtained by subtracting the shortened time from the takt time is equal to or less than a cycle time, calculates the time obtained by subtracting the cycle time from the takt time as the shortened time ;
A change unit that changes the production plan,
The change unit is
If the reduced takt time is longer than the cycle time, the production plan is changed to a production plan using the reduced takt time,
When the reduced takt time is equal to or less than the cycle time, the production plan is changed to a production plan that uses the reduced takt time and includes a reduction in the target production quantity . The production planning system according to claim 1,
The production line includes a plurality of the facilities,
the grace period and the maintenance work period are determined in advance for each of the plurality of facilities,
When the determination unit determines that the detection value for the plurality of pieces of equipment has exceeded the reference value, the calculation unit calculates the shortened time using the grace time of the piece of equipment having the shortest grace time among the plurality of pieces of equipment for which it has been determined that the detection value has exceeded the reference value, and a longest maintenance work time which is the maintenance work time of the piece of equipment having the longest maintenance work time,
The change unit sets a time for stopping the production line in order to perform the maintenance work on the plurality of pieces of equipment within the longest maintenance work time. 3. The production planning system according to claim 1 ,
The determination unit is
The device is capable of communicating with a storage unit in which prediction data is stored in which the limit value, which is the detection value at the prediction time, the reference value, and the equipment are associated with each other;
The determination unit is
A production planning system that makes a judgment using the reference value of the prediction data. The production planning system according to claim 3 , further comprising:
A production planning system comprising: a setting unit that sets the grace time to a longer value as the maintenance work time is longer. A production planning method, comprising:
The production planning method includes: a planning step of creating a production plan for a production line, the production plan including a takt time calculated by dividing an operating time of the production line by a target production volume;
a judgment step of judging whether a detection value indicating the performance of equipment used in the production line exceeds a reference value which is a predicted value of the detection value at a reference time obtained by subtracting a grace period from a predicted time when maintenance work for the equipment is predicted to be required;
an acquisition step of acquiring a maintenance work time required for the maintenance work when it is determined in the determination step that the reference value has been exceeded;
a calculation step of calculating a shortened time of the takt time for generating the maintenance work time within the grace time by using the grace time and the maintenance work time , and when a shortened takt time obtained by subtracting the shortened time from the takt time is equal to or less than a cycle time, calculating a time obtained by subtracting the cycle time from the takt time as the shortened time;
and a changing step of changing the previous production plan to the production plan using the reduced takt time when the reduced takt time is longer than the cycle time, and changing the previous production plan to the production plan using the reduced takt time, which includes a reduction in the target production quantity, when the reduced takt time is equal to or less than the cycle time.

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