JP2003114711A - Process planning method, process planning assisting method, process planning system, process planning assisting system, manufacturing method and program, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a processing plan with the manufacturing time shortened by reducing the dead time generated under a process planning method based on the first-come-first-served policy in handling parts. SOLUTION: The manufacturing time is reduced by reversing the processing order of parts having much time to wait and that of parts in the critical path.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process planning method for shortening the manufacturing period in a production system for manufacturing a product by combining a plurality of parts processed in a plurality of steps into a new part. It is related to technology related to.

[0002]

2. Description of the Related Art In the conventional process planning method, in order to increase the operation rate of a process (minimize idle time), parts which can be started at that time are selected based on various start (dispatching) rules. The process plan is created by the procedure of selecting and starting the work, and when the work of the part is finished, the work is selected again from the workable parts at the time when the work is started. As for the construction rule, the first-in first-out method that processes the parts that arrive earlier, the method that prioritizes each part as in the case of express processing, and processes in that order,
There is a method in which a component having a long sum of processing times of the component after the process is processed first.

FIG. 2 shows an example of a process plan prepared by a conventional process planning method. With reference to FIG. 2, a construction rule for starting construction from the conventional workable parts will be described. In FIG. 2, the horizontal axis represents the time axis, the vertical axis represents the parts P1 to P4, and the letters M1 to M11 in the box represent the processes. In addition, the part P1 passes through the steps of M1, M4, M8, M9, and M10.
The component P2 indicates that it passes through the steps of M2, M4, and M6, and the component P3 indicates that it passes through the steps of M3, M5, M7, and M8. Further, the parts of P1 to P3 are combined into P4, which means that the process of M11 is performed.

First, the part P1 is processed in the process M1, the part P2 is processed in the process M2, and the part P3 is processed in the process M.
The process is planned to be processed at 3. At this time, M
Steps 4 to M11 are vacant because they cannot be performed in the next step unless the steps M1 to M3 are completed. When the process of M2 of the part P2 is finished, the process of M4 comes to be performed, so that the part P2 is subjected to the process of M4. The part P3 is subjected to the step M5 after the step M3. The component P1 is subjected to the process M4 after the process M1, but the process M4 is used by the component P2, so that there is a waiting time T1. Also in the step M8, since the part P3 is put on first, the part P1 has the waiting time T2, and after the part P3 is finished, it is put on the step M8. Part P2 is process M6
It ends up to, but when combined with parts P1 and P3, part P4
Therefore, the completion of the component P1 is kept waiting. Part P3
Although the process ends up to the step M8, the process waits until the part P1 is completed. The part P1 ends up to the step M10, and is combined with the already completed parts P2 and P3 to become the part P4.
The process M11 is performed. In this case, the manufacturing period is the period from the start of manufacturing to the end of step M11.

[0005]

In the process plan of FIG. 2,
Although the manufacturing period of the part P1 is determined, there is a dead time of T1 and T2 in the process plan. Also, the parts P2, P
With respect to 3 as well, there is a waiting time after the completion of the parts because the completion of the combined parts P1 is waited for. Originally, the part P1 that takes a long time to manufacture should be processed with priority, and such a construction rule is selected in the above process plan as well. However, in order to increase the operation rate of the process, As a major premise, there is a rule to select from the parts that can be started, so the result is as above.
The above result does not always occur. For example, as shown in FIG. 3, if the time of the process M1 and the process M2 are reversed or finished at the same time, the component P1 is first applied to the process M4, and as a whole, It will be manufactured in a shorter period than shown in 2.

In order to give priority to shortening the manufacturing period rather than to prioritize the operating rate, if the rule of selecting from the parts that can be started is eliminated, all parts for which the start of decision is to be made may pass through the process in the future. Since it spreads to parts, there are too many options and it becomes difficult to determine the process plan.

The object of the present invention is that the process plan preparation process on the computer system can be practically and easily achieved even when the operating period is prioritized and the manufacturing period is shortened, which greatly contributes to the reduction of the manufacturing period. To provide a process planning method.

[0008]

In order to achieve the above object, the process planning method according to the present invention includes a step of creating a process plan according to the rule of starting the work from the startable parts, and at each confluence point. The step of calculating the margin time until the product completion of each part by summing the difference between the completion time of the pre-merging process and the start time of the post-merging process, and the route with the minimum margin time is the critical path. And a step of calculating the waiting time of each post-process from the difference between the pre-process completion time and the post-process start time in the critical path, and the critical path bottles in descending order of the waiting time. For all parts performing the same process as the bottleneck process during the step of selecting as the neck process and the waiting time of the bottleneck process The step of calculating the allowance time and the spare time of the part performing the same process as the bottleneck process during the waiting time of the bottleneck process are the work of the bottleneck process of the part of the critical path. A step of determining whether or not it is longer than the time, and, in accordance with this determination result, the same step in the component performing the same step as the bottleneck step during the waiting time of the bottleneck step, Steps to fix the schedule of the bottleneck process so that the processing order of the parts of the critical path and the bottleneck process may be exchanged, and from among the parts that can start construction for other parts and processes after fixing the schedule Steps to create a process plan based on the rule of starting construction, and determine whether the product completion date has become earlier And the step, if the product completion date had become faster, and a step to do this with the new process plan includes.

By providing each of the above processing steps, the critical path parts are preferentially started instead of selecting from the startable parts, thereby realizing the priority of shortening the manufacturing period rather than the priority of the operating rate. It becomes possible. Moreover, by limiting the parts subject to the start of work to those selected in the process plan created by the rule of starting work from critical path parts and startable parts, even with a reduction in the manufacturing period, The process of creating a process plan on a computer system can be easily achieved practically.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 8 is a block diagram of a computer system (an embodiment of the process planning system) in which each process of the process planning method according to the embodiment of the present invention is executed. In FIG. 8, reference numeral 1 is a processor unit (a control device having an OS) that performs overall control of the entire system, 2 is an input device such as a keyboard and mouse, 3 is a display device such as a liquid crystal display, and 4 is a color page printer. And the like, 5 is a disk storage device such as an HDD and an optical disk device, 6 is a network adapter for connecting an external device to this system via a network, and 7 is installed in an appropriate memory of this system. These components 1 to 7 are connected by a bus 8 in a process plan creation application program (process plan creation software). The functions of the respective means in the claims are realized by executing the process plan creation application.

FIG. 1 is a flow chart showing the process flow of the process planning method of this embodiment. Hereinafter, the processing procedure of the process planning method of the present embodiment will be described.

First, a process plan is prepared on the basis of the conventional construction rule that construction is started from the workable parts (step S1). As a result, the process plan of FIG. 2 described above is created.

Next, for each part, the difference between the completion time of the pre-merging process and the start time of the post-merging process at each confluence point is summed up to calculate the margin time until the product is completed for each part (step). S2). This will be described with reference to FIG.

In FIG. 4, the horizontal axis represents the time axis and the vertical axis represents the parts. The parts P1 to P3 are combined to form a part P4. Parts P5 and P6 are also combined to make a part P7
Becomes Further, the parts P4 and P7 are combined to form the part P8, and when the process of the part P8 is completed, the product is completed. The difference between the pre-merging process completion time and the post-merging process start time at the confluence point before the component P4 is as follows. Part P1
, The final process of the component P2, the final process of the component P3 is the pre-merging process, and the first process of the component P4 is the post-merging process.
The difference between the completion time of the pre-merging process and the start time of the post-merging process is 0 for the component P1, T3 for the component P2, and T4 for the component P3.
Similarly, 0 is between the parts P5 and P7, T5 is between the parts P6 and P7, 0 is between the parts P4 and P8, and T6 is between the parts P7 and P8.

From the above, when the difference between the completion time of the pre-merging process and the start time of the post-merging process at each confluence point is summed up for each part, the margin time of the parts P1 and P4 is 0, and the margin of the part P2 is 0. The time is T3. Below, the spare time of each component is T4 for component P3, T6 for component P5 and P7, and component P6.
Becomes T5 + T6.

Since the margin time is calculated as described above, the route having the smallest margin time is selected as the critical path to be improved (countermeasure) from the routes of the respective parts (step S3). In the example of FIG. 4, the paths of the parts P1, P4, and P8 are critical paths.

Next, in the critical path, the waiting time of each post-process is calculated from the difference between the pre-process completion time and the post-process start time (step S4). This will be described with reference to FIG. In the component P1, the difference between the completion time of the process M1 and the start time of the process M4 is T1. Therefore, the waiting time of the process M4 is T1. Hereinafter, similarly, the waiting time of the step M8 is T2, and the waiting times of the steps M9 and M10 are 0.

Next, from the longest waiting time, the critical path bottleneck process is selected in order (step S5). In the example of FIG. 2, T1 is larger than T2, so the steps M4, M8, M9, and M10 are performed in this order.
Hereinafter, the processes described below are repeated in order from the highest order, and when all the bottleneck processes of the critical path have been processed, the process plan creation process ends (step S6).

If the critical path bottleneck process still exists, the following process is performed. For example, in the case of FIG. 2, first, the following process is performed for the process M4.
First, during the waiting time (waiting time T1) of the bottleneck process (process M4), all the parts performing the same process (process M4) as this bottleneck process (that is, M4 is processed). As for all the parts that are owned by and working at T1), the margin time is calculated (step S7). In the case of FIG. 2, the margin time is calculated for the component P2 that is working in the process M4 during T1. In this case, the margin time of the component P2 is T3.

Next, the spare time (here, the spare time T3 of the component P2) calculated in step S7 is the working time of the bottleneck process of the critical path component (here, the process M4 of the component P1). It is determined whether it is longer than the working time) (step S8). In the case of FIG. 2, T3 is longer than the working time of the process P4 for the component P1, so the process proceeds to the following process. If it is smaller, there is no room to change the processing order of the parts, so the process returns to step S5 and the process with the next longest waiting time is selected as the bottleneck process.

If the spare time of the component calculated in step S7 is larger than the working time of the bottleneck process of the critical path component, the process corresponding to the bottleneck process of the component calculated in step S7. For (the same process as the bottleneck process), the schedule of the bottleneck process is fixed so that the parts in the critical path and the processing order thereof are exchanged (step S9). An example thereof is shown in FIG. In FIG. 5, the process M
4, the processing order of the component P2 and the component P1 of the critical path is exchanged. At this time, the schedule is fixed in the step M4 of the part P1 and all the steps before the part P1 (step M1 in FIG. 5).

Next, a process plan is created under the rule that the schedule of the bottleneck process is fixed, and then the other parts and processes are started from the startable parts (step S10). In the case of FIG. 5, the remaining steps are re-planned at this stage, resulting in the result shown in FIG. In FIG. 5, as a result of exchanging the process M4 of the component P1 and the process M4 of the component P2 (the result of eliminating the waiting time T1 of the component P1), the component P1 starts the process M8 earlier than the component P3. Therefore, the waiting time T2 for the component P1 is also eliminated.

Next, it is judged whether or not the product completion date is earlier than the conventional process plan (step S11).
In the case of FIG. 5, it can be seen that the product completion date is earlier than that of FIG.

If the product completion date is early, a process plan with a fixed bottleneck process schedule is set as a new process plan (step S13), and the process returns to step S2 to examine whether it can be further packed. If the product completion date is not early, it means that the order change has had an adverse effect, so the schedule is released (step S12), the process returns to step S5, and the process with the next longest waiting time is selected. (For example, wait time T2
Process M8 of No. 3 is selected as the bottleneck process of the critical path).

As described above, the processing flow ends when all the bottleneck steps of the critical path have been processed. However, it may take a very long time when the number of parts and the number of processes increase, so that a method of interrupting the processing after a certain time has passed may be adopted.

Next, another embodiment of the present invention will be described. In the process planning method of the present invention, a person can perform the process shown in FIG. Even in that case, it takes too much time if a person performs all the processes, so the following process is performed.

That is, steps S1 to S4
The processing up to is automatically performed. After that, the waiting time of each process is displayed in a graph as shown in FIG. 6, and it is assumed that a person determines which process is to be the bottleneck process of the critical path.

Subsequently, the process of step S7 is automatically performed, and the result is displayed in a graph as shown in FIG.
It is up to the person to decide which component is to be replaced with the component in the critical path in the processing order.

Next, the process of step S10 is automatically performed, and the determination of the result is left to a person.

According to the process planning support method or the process planning support method as described above, the manufacturing process can be performed in a shorter time than the automatic process by the experienced person selecting the process and the parts to be processed. It is also possible to obtain a process plan with a short period.

A process plan created by the process planning method or process planning system described above, or a process plan created by using the process planning support method or process planning support system can shorten the manufacturing period. Therefore, in the method of manufacturing a product that executes such a process plan, it becomes possible to introduce a new product or the like to the market before others.

In the process planning system of FIG. 8 described above, the system is constructed by a single computer (computer) system. However, the process planning system of FIG. 8 is used as a host computer system, and the host computer system is connected to the Internet. The client computer system may be connected via a wide area communication network such as. In this case, from the client computer system, information about the parts that make up the product necessary for the process plan creation process, and the processes and process orders and the process times that need to be applied to each part is sent via the network. Send to the host computer system, and in the host computer system,
The processing result (created process plan data or created process plan creation support data) is transmitted to the client computer system via the network. At this time, when transmitting the processing result from the host computer system, a business form may be adopted in which charging is performed according to the processing time or the like.

The process planning method described above is
The program is realized by a program for causing the process plan creation process to function, and the present invention may be the program itself or a computer-readable recording medium storing the program.

[0035]

As described above, according to the present invention, in a production system in which parts compete for each other (manufacturing equipment, etc.), a process plan in which the processing order of a critical path part and a part having a spare time is exchanged When the product completion date becomes short, the starting order is adopted, and it is impossible to create a free time in the process that cannot be created by the starting rule of starting from the conventional startable parts. It is possible to shorten the manufacturing period by creating a process plan that prioritizes parts on the critical path. Therefore, since it is possible to shorten the manufacturing period, it is possible to shorten the period until the introduction of a new product to the market, and by selling at a high price by leading the competition, many You can make a profit.
Further, by shortening the manufacturing period, it is possible to shorten the period up to the collection of invested funds and improve the cash flow.

[Brief description of drawings]

FIG. 1 is a flowchart showing a processing flow according to an embodiment of a process planning method of the present invention.

FIG. 2 is an explanatory diagram showing an example of a process plan created according to a construction rule that construction is started from parts which can be constructed.

FIG. 3 is an explanatory diagram showing an example of a process plan created according to a construction rule that construction is started from parts that can be constructed when the process work time is different from that in FIG. 2;

FIG. 4 is an explanatory diagram showing a margin time and a critical path in a product manufactured by combining a plurality of parts.

FIG. 5 is an explanatory diagram showing an example of a process plan created by an embodiment of the process planning method of the present invention.

FIG. 6 is an explanatory diagram showing an example of a graph displaying a waiting time of each process.

FIG. 7 is an explanatory diagram showing an example of a graph displaying a margin time of each component.

FIG. 8 is a schematic configuration diagram of an embodiment of a process planning system of the present invention.

[Explanation of symbols]

1 processor unit 2 input devices 3 display devices 4 printers 5 Disk storage 6 network adapter 7 Process planning application 8 buses S1 to S13 processing steps P1 to P8 parts M1-M11 process T1-T6 hours

Claims (11)

[Claims] 1. A step of creating a process plan according to the rule that construction is started from the parts that can be constructed, and the difference between the completion time of the pre-merging process and the start time of the post-merging process at each confluence point is calculated for each part. Totaling, calculating a margin time until product completion of each component, determining the route with the minimum margin time as a critical path, pre-process completion time and post-process start time in the critical path The step of calculating the waiting time of each post-process from the difference between, and the step of selecting the bottleneck process of the critical path in order from the one with the longest waiting time, and the bottleneck during the waiting time of the bottleneck process. The step of calculating the margin time for all parts performing the same process as the neck process and the waiting time of the bottleneck process. A step of determining whether or not the spare time of the part performing the same process as the Torneck process is greater than the work time of the bottleneck process of the critical path part; In order to switch the processing sequence between the bottleneck process of the critical path component and the same process in the component performing the same process as the bottleneck process during the waiting time of the bottleneck process, The steps to fix the schedule of the neck process, the step to create the process plan based on the rule that the schedule is fixed, and then the other parts and processes are started from the parts that can be started. If the product completion date is earlier than the step to determine whether or not it is a new process plan, A process planning method comprising the steps of: 2. The process planning method according to claim 1, wherein the process is interrupted when a certain time has elapsed. 3. The step of creating a process plan based on the rule that construction is started from the startable parts, and the difference between the completion time of the pre-merging process and the start time of the post-merging process at each confluence point is calculated for each part. The step of totaling and calculating the margin time until the product completion of each part, the step of determining the route with the minimum margin time as a critical path, and the step between the completion time of the previous process and the start time of the subsequent process A process planning support method comprising: a step of calculating a process waiting time; and a step of displaying the calculated waiting time of each process. 4. The method according to claim 3, further comprising: during a waiting time of a designated process, calculating a margin time with respect to all components performing the same process as the designated process. And a step of displaying the calculated margin time, the process planning support method. 5. The method according to claim 4, further comprising a step of creating a process plan based on a rule that a schedule is fixed, and then other parts and processes are started from parts that can be started. And the process planning support method. 6. A program for causing a computer to execute each processing step according to claim 1. Description: 7. A computer-readable recording medium having the program according to claim 6 stored therein. 8. A component of a product, a process and a process sequence required to be performed on each component, and each process time,
Information is obtained from the requesting side via the network, and is created by using the process plan data created by the process planning method according to claim 1 or 2 or the process planning support method according to claim 3 or 4 or 5. A process planning method characterized in that the created process plan creation support data is passed to a requesting side via a network with a charge. 9. A process planning means for creating a process plan based on the rule that construction is started from the startable parts, and the difference between the completion time of the pre-merging process and the start time of the post-merging process at each confluence point is calculated for each part. Respectively, the calculating means for calculating the margin time until the product completion of each part, the determining means for determining the route with the minimum margin time as a critical path, and the previous process completion time in the critical path Calculation means for calculating the waiting time of each post-process from the difference with the post-process start time, selecting means for selecting as the bottleneck process of the critical path in order from the one with the longest waiting time, and the waiting time of the bottleneck process Between the calculation means for calculating the margin time for all parts performing the same process as the bottleneck process, and the waiting time of the bottleneck process. Determination means for determining whether or not the spare time of the component performing the same process as the bottleneck process is greater than the work time of the bottleneck process of the component of the critical path, and according to the determination result , During the waiting time of the bottleneck process, the processing order of the same process in the component performing the same process as the bottleneck process and the bottleneck process of the component in the critical path is switched. , A process planning means that fixes the bottleneck process schedule, and a process planning means that creates a process plan based on the rule that the schedule is fixed, and then other parts and processes are started from the parts that can be started. A means to determine whether the completion date is earlier, and if the product completion date is earlier, use this as a new process plan. A process planning system comprising: a process planning means as an image. 10. A process planning means for creating a process plan based on the rule that work is started from the startable parts, and the difference between the process completion time before the process and the process start time after the process at each meeting point is calculated for each part. The calculation means for calculating the margin time until product completion of each part, the determination means for determining the route with the minimum margin time as the critical path, the pre-process completion time and the post-process start time A process planning support system comprising: a calculating unit that calculates a waiting time of each subsequent process based on the difference; and a unit that displays the calculated waiting time of each process. 11. A process plan created by the process planning method according to claim 1 or 2 or the process planning system according to claim 9, or the process planning support method according to claim 3 or 4 or 5. A product manufacturing method, which comprises manufacturing a product based on a process plan created by using the process planning support system according to claim 10.