Production planning system, production planning method, and program

Abstract

To provide a method for calculating the number of units that can actually be produced based on a production plan while taking into consideration stockout of parts.SOLUTION: A production planning system includes: means for classifying whether a product can be produced or not based on an expected delivery of parts constituting the product with respect to a production plan of the product; means for calculating a predicted value of a stockout risk rate, which indicates a ratio of the number of units that can actually be produced to the number of units that have been planned, by analyzing an impact of the number of units that could not be produced due to a stockout of the parts on the number of units that have been planned in a production plan that has been made in the past; and means for calculating the number of units that can be produced by multiplying the number of units that have been classified as unproductive in the classification of whether or not production is possible by the predicted value of the stockout risk rate.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to a production planning system, a production planning method, and a program. [Background technology]

[0002] Maintaining and managing the supply chain requires meeting customer delivery deadlines and maximizing business profits. However, as the number of customer requests and the variety of products increase, it becomes difficult to standardize production times and keep inventory for each delivery date in production planning tasks, which often results in unnecessary inventory and production costs.

[0003] Patent Document 1 discloses a production planning system that receives production request information, bill of materials information, and information on the inventory and planned arrival of each part for a product, and when formulating a production plan for the product, if there are parts that cannot be produced, sets the parts that cannot be produced as new required quantities for a date after the date specified in the production request information and formulates a production plan.The technology in Patent Document 1 not only determines whether production is possible in response to customer requests, but also calculates the maximum number of units that can be manufactured.Patent Document 2 also discloses a production planning system that formulates a production plan by performing a leveling process that distributes production each day in accordance with the factory's production capacity.

[0004] Generally, production plans are often created to meet customer delivery deadlines on the assumption that the parts required for production are available. However, for example, in the current semiconductor shortage, when parts are procured from suppliers, there is a possibility that the delivery date of the parts may be extended just before production begins. In such cases, parts may be in short supply, making it impossible to produce the planned number of units even if a production plan is created, resulting in the waste of resources that have already been procured. Neither Patent Document 1 nor Patent Document 2 discloses estimating the number of units that can actually be produced while taking into account parts shortages. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-072781 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-268726 Summary of the Invention [Problem to be solved by the invention]

[0006] One of the objects is to provide a method for calculating the number of units that can actually be produced based on a production plan while taking into account the shortage of parts. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, a production planning system includes: a means for classifying a production plan for a product as producible or unproducible based on expected delivery of parts that make up the product; a means for calculating a predicted value of a stockout risk rate, which indicates the ratio of the number of units that can actually be produced to the planned number of units that can be produced, by analyzing the impact of the number of units that could not be produced due to a shortage of parts on the number of units that were planned in the production plan that was previously drawn up; and a means for calculating the number of units that can be produced that can be considered producible by multiplying the number of units that were classified as unproducible in the producible or unproducible classification by the predicted value of the stockout risk rate.

[0008] According to one aspect of the present disclosure, a production planning method is executed by a computer and includes the steps of: classifying a production plan for a product as producible or unproducible based on expected deliveries of parts that constitute the product; calculating a predicted value of a stockout risk rate, which indicates the ratio of the number of units that can actually be produced to the planned number of units that can be produced, by analyzing the impact of the number of units that could not be produced due to a shortage of parts on the number of units that were planned in the production plan that was previously formulated; and calculating the number of units that can be produced that can be considered producible by multiplying the number of units that were classified as unproducible in the producible or unproducible classification by the predicted value of the stockout risk rate.

[0009] According to one aspect of the present disclosure, a program causes a computer to execute the following steps: classifying a production plan for a product as producible or unproducible based on expected deliveries of parts that make up the product; calculating a predicted value of a stockout risk rate that indicates the ratio of the number of production units that can actually be produced to the planned number of production units by analyzing the impact of the number of production units that could not be produced due to a shortage of parts on the number of production units planned in the production plan that was previously formulated; and calculating the number of production units that can be considered producible by multiplying the number of production units classified as unproducible in the producible or unproducible classification by the predicted value of the stockout risk rate. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to calculate the number of units that can be produced based on a production plan while taking into account the possibility of parts being out of stock. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an example of a production planning system according to an embodiment. [Figure 2] 1 is a flowchart illustrating an overall production planning process according to an embodiment. [Figure 3] 10 is a flowchart illustrating an example of a process for classifying whether or not a product can be produced according to the embodiment. [Figure 4] 10 is a flowchart illustrating an example of a process for predicting the impact of a parts shortage according to the embodiment. [Figure 5] 10 is a flowchart illustrating an example of a process for calculating a stockout risk rate transition according to the embodiment. [Figure 6] 10 is a flowchart illustrating an example of a correction process for a production plan according to the embodiment. [Figure 7] FIG. 2 is a second diagram illustrating an example of a production planning system according to an embodiment. [Figure 8] 4 is a flowchart showing an example of an operation of the production planning system according to the embodiment. [Figure 9] FIG. 1 is a diagram illustrating an example of a hardware configuration of a production planning system according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] A production planning system according to each embodiment of the present disclosure will be described below with reference to the drawings. In the drawings used in the following description, the description of parts not related to the present disclosure may be omitted or not shown. The same or equivalent parts in all drawings will be denoted by the same reference numerals, and common descriptions may be omitted.

[0013] First Embodiment (System Configuration) 1 is a diagram showing an example of a production planning system according to an embodiment. The production planning system 10 includes a requirements information DB 1, a production information DB 2, a production plan calculation unit 3, a production plan DB 4, a parts supply DB 5, and a production plan correction unit 6. DB stands for database.

[0014] The requirement information DB1 stores the required information from customers that is used to create a production plan. For example, the requirement information DB1 stores the identification information, quantity, delivery date, etc. of products ordered by customers.

[0015] The production information DB2 stores the prerequisites and constraints for the target product for which a production plan is being created. For example, the production information DB2 stores information such as the parts required to manufacture the target product, the expected delivery date of the parts, the expected delivery quantity, and delivery results.

[0016] The production plan calculation unit 3 creates a production plan from the requirements information DB1 and production information DB2. There are no particular limitations on the production plan method. The production plan calculation unit 3 calculates the production plan using any known method. For example, the production plan calculation unit 3 calculates the time required for production based on customer requests in accordance with the factory's production capacity, performs leveling processing to average production resources over a certain period and distribute production among days, and then allocates the number of units to be produced to the averaged resources in line with the customer's delivery date, thereby creating a production plan.

[0017] The production plan DB 4 stores the production plans formulated by the production plan calculation unit 3. The production plan DB 4 also records the results of the formulated production plans. The parts supply DB 5 stores information on parts that have been confirmed to be delivered by suppliers, among the parts used in the latest production plan stored in the production plan DB 4.

[0018] The production plan correction unit 6 corrects the number of products planned to be manufactured in the production plan to a production number that takes into account the possibility of parts being out of stock, based on the production plan stored in the production plan DB 4 and the parts supply DB 5.

[0019] (operation) Next, the overall flow of the production plan creation process will be explained using FIG. FIG. 2 is a flowchart showing the overall production planning process according to the embodiment. First, the production planning system 10 classifies whether production is possible or not (step S100). Next, the production planning system 10 performs a process of predicting the risk of stockout (step S200). Next, the production planning system 10 performs a process of correcting the production plan (step S300).

[0020] Next, the process of classifying whether production is possible or not in step S100 will be described with reference to FIG. FIG. 3 is a flowchart illustrating an example of a process for classifying whether or not a product can be produced according to the embodiment. First, the production plan calculation unit 3 reads information from the requirements information DB1 and the production information DB2 and performs processing to formulate a production plan (step S110). For example, the production plan calculation unit 3 formulates a production plan by performing the leveling process disclosed in Patent Document 2. The production plan calculation unit 3 stores the formulated production plan in the production plan DB4. The production plan includes information on which parts to use, how many units to produce, and by when for each product.

[0021] Next, the production plan calculation unit 3 refers to the production information DB2 and the production plan DB4, and performs a process to extract the delivery quantities of parts required for the production quantity planned in step S110 (step S120). The production plan calculation unit 3 refers to the production information DB2, and calculates the expected delivery quantities of parts to be used in the proposed production plan, taking into account the planned delivery date and planned delivery quantity of each part that makes up the product. The production plan calculation unit 3 stores information on the parts that have been decided to be used in the fulfillment DB5.

[0022] Next, the production plan calculation unit 3 classifies the units as producible or unproducible based on the expected delivery quantity calculated in step S120 (step S130). The production plan calculation unit 3 determines that the number of units that can be produced based on the expected delivery quantity is producible, and calculates the number of units that cannot be producible by subtracting the number of units determined to be producible from the number of units planned for production.

[0023] Next, the process of predicting the risk of stockout in step S200 will be described with reference to FIG. FIG. 4 is a flowchart illustrating an example of a process for predicting the impact of a parts shortage according to the embodiment. First, the production plan correction unit 6 performs a process to calculate the actual result start date (step S210). The production plan correction unit 6 references the production information DB2 and extracts the number of days T1 (i.e., the lead time) of the part that has the longest lead time from the time the part is procured until delivery to the factory, among the parts that make up the product. The production plan correction unit 6 sets the actual result start date as the date that is the number of days T1 back from the production plan creation date. Next, the production plan correction unit 6 calculates the past average stockout risk rate α (step S220). Based on past performance, the production plan correction unit 6 calculates the average stockout risk rate α using the following formula (1) for each production plan created during the period T from the actual result start date calculated in step S210 to the present, by accumulating the planned production quantity PQ and the accumulated quantity MQ of units that could not be produced due to parts shortages. α=(ΣPQ−ΣMQ) / ΣPQ···(1)

[0024] Next, the production plan correction unit 6 calculates the cyclical fluctuation rate γ (step S230). The production plan correction unit 6 calculates the cyclical fluctuation rate γ from fluctuations in the stockout risk rate that occurred periodically in the past, using the following formula (2). γ = int(X / f(t)) × Z (2) In formula (2), int() represents a function that rounds down the numbers in parentheses. Furthermore, X represents the unit for which production planning is carried out (in this example, it is assumed that production planning is carried out on a weekly basis), and Z represents the stockout risk rate that occurs in each cycle. For example, if the present is week 0 and the performance start date is 20 weeks ago, then values ​​such as 0, -1, -2, ..., -20, etc. are substituted for X. Furthermore, f(t) (t is time) is a function that returns the time when stockouts will occur according to the cycle in which the stockout risk rate fluctuates. For example, if stockouts occur every four weeks, f(t) will follow this cycle and return values ​​such as 0, -4 (for example, t is entered with a value indicating how many weeks ago it is from the present (the date the production plan was created), just like X, and if t is -1 to -4, f(t) = -4; and so on), -8 (if t is -5 to -8), -12 (if t is -9 to -12), -16 (if t is -13 to -16), -20 (if t is -17 to -20), etc. If values ​​such as 0, -1, -2, ..., -20 are substituted for X, and 0, -4, -8, -12, -16, or -20 are substituted, which are the weeks in which stockouts occur, then the value of int(X / f(t)) will be 1 and γ will be Z. On the other hand, when values ​​such as -1, -2, -3, -5, . . . , -19, which do not result in stockouts, are substituted for X, the value of int(X / f(t)) becomes 0, and therefore γ also becomes 0. In other words, equation (2) means that the cyclical fluctuation rate γ becomes the stockout risk rate Z every four weeks (four weeks is just an example, and other cycles are acceptable), and is 0 in other weeks. (In equation (7), which shows the transition of the stockout risk rate, γ = Z is added every four weeks, and γ = 0 is added in other weeks.) The production plan correction unit 6 refers to the production information DB2 and the production plan DB4, analyzes the periodic occurrence of a failure to produce the planned number of units due to parts shortages, and calculates Z = (PQ - MQ) / PQ using the planned number of units to be produced PQ and the number of units that could not be produced due to parts shortages MQ.

[0025] Next, the production plan correction unit 6 calculates the sudden fluctuation rate σ (step S240). Taking into consideration the occurrence of an event that is expected to have a stockout impact in a future period, the production plan correction unit 6 calculates the sudden fluctuation rate σ using the following formula (3) from the stockout risk rate change value α1 when a past event occurred (an event that may cause a stockout) and the number of past event occurrences HC. σ=Σα1 / HC (3)

[0026] Next, the production plan correction unit 6 performs a process of calculating the stockout risk rate transition (step S250). Here, the process of predicting the risk of stockout in step S250 will be described with reference to FIG. FIG. 5 is a flowchart showing an example of a process for calculating a stockout risk rate transition according to the embodiment. The production plan correction unit 6 extracts the stockout risk rate for each production plan formulated during the period from the actual performance start date calculated in step S210 to the present, arranges the extracted stockout risk rates in chronological order, and calculates the fluctuation rate β1 by drawing an approximate line (a line expressed by the following approximate formula (4)) (step S251). For example, suppose a production plan is formulated to produce three units of a certain product per day from the actual performance start date to the present, and three units were produced on day D1, but only two units were produced on day D1+1 due to a stockout, etc. The production plan correction unit 6 extracts the stockout risk rate for each time-series production plan by calculating (PQ-MQ) / PQ for each day. The fluctuation rate β1, which indicates the change in the stockout risk rate, is the coefficient of the first-order term in the approximate formula (4) below, where Y1 is the stockout risk rate and X is time. Y1=β1X+C1 (4)

[0027] Next, the production plan correction unit 6 calculates the extension rate β2 from the standard lead time SLT at the time of ordering the parts and the lead time PLT of the parts that have been delivered with an extended delivery date (step S252). The extension rate β2 can be expressed by the following equation (5). Σ in equation (5) means that the sum of the actual delivery date extensions is calculated relative to the total SLT from the actual date of origin to the present for all ordered parts, regardless of the type of part. β2=Σ(SLT−PLT) / ΣSLT···(5)

[0028] Next, the production plan correction unit 6, taking into account the sudden extension of the delivery date of the parts, sets the shortest date of the parts lead time as the starting date, extracts the stockout risk rate from the starting date to the current day, arranges them in chronological order, and calculates the latest fluctuation rate β3 by drawing an approximate straight line (step S253). For example, for each production plan created in the past, the production plan correction unit 6 calculates the stockout risk rate due to stockout of the various parts required to produce the products related to that production plan from the shortest lead time (the shortest lead time of all parts) among the lead times (which have a range) set for each of the parts required to produce the products related to that production plan to the current day (the date the production plan was created), arranges them in chronological order, and draws an approximate straight line. The latest fluctuation rate β3 can be expressed as the coefficient of the first-order term in the following equation (6). Y3=β3X+C3 (6)

[0029] Next, the production plan correction unit 6 calculates a future transition Y of the stockout risk rate by combining steps S210, S220, S230, S240, S251, S252, and S253, and a variable X representing time (step S254). The transition Y of the stockout risk rate can be expressed by the following equation (7). The time elapsed from the actual start date is input as X. Y=α+(β1+β2+β3)X+γ+σ···(7) This makes it possible to predict future trends in stockout risk rates based on past stockout risk records.

[0030] Next, the correction process of the production plan in step S300 will be described with reference to FIG. FIG. 6 is a flowchart illustrating an example of a process for predicting the impact of a parts shortage according to the embodiment. The production plan correction unit 6 calculates the stockout risk rate for each time series of the production plan using the equation for the transition of the stockout risk rate calculated in step S254 (step S310). Next, the production plan correction unit 6 multiplies the stockout risk rate for each time series calculated in step S310 by the number of units in the production plan that cannot be produced calculated in step S130, and corrects it to the expected producible production number that takes stockout risk into account (step S320). If the number of units that cannot be produced calculated in step S130 out of the number of units to be produced at time T is AT, and the number obtained by multiplying AT by the stockout risk rate for time T is BT, the production plan correction unit 6 calculates the number of units that can be produced using parts that are procured from now out of the number of units that were deemed unproducible in step S130. The production plan correction unit 6 adds the time-series BT calculated for each time to the number of units determined to be producible in step S130 to calculate the expected producible production number.

[0031] (effect) As described above, according to the first embodiment, it is possible to calculate the number of units that can be produced, taking into account the impact of parts shortages. This makes it possible to correct the proposed production plan to a feasible production plan, and to prevent the need to secure excessive production resources and human resources. This contributes to maximizing business profits and reducing inventory.

[0032] Second Embodiment FIG. 7 is a second diagram illustrating an example of the production planning system according to the embodiment. The production planning system 800 includes a classification means 801 that classifies a product's production plan into whether it is producible or not based on the expected delivery of parts that make up the product; a predicted value calculation means 802 that calculates a predicted value of a stockout risk rate, which indicates the ratio of the number of units that can actually be produced to the planned number of units, by analyzing the impact of the number of units that could not be produced due to stockouts of the parts on the number of units planned in the production plan formulated in the past; and a quantity calculation means 803 that calculates the number of units that can be produced by multiplying the number of units classified as unproducible in the producible or not classification by the predicted value of the stockout risk rate. The production plan calculation unit 3 is an example of the classification means 801. The production plan correction unit 6 is an example of the predicted value calculation means 802 and the number calculation means 803.

[0033] FIG. 8 is a flowchart showing an example of the operation of the production planning system according to the embodiment. The production planning system 800 classifies a product's production plan as producible or unproducible based on the expected delivery of parts that make up the product (step S801). For previously formulated production plans, the system analyzes the impact of the number of units that could not be produced due to a shortage of parts on the planned number of units to be produced in the production plan, and calculates a predicted value of the stockout risk rate, which indicates the ratio of the number of units that can actually be produced to the planned number of units to be produced (step S802). The system calculates the number of units that can be produced by multiplying the number of units classified as unproducible in the producible or unproducible classification by the predicted value of the stockout risk rate (step S803).

[0034] FIG. 9 is a diagram showing an example of the hardware configuration of a production planning system. The computer 900 includes a CPU 901, a main storage device 902, an auxiliary storage device 903, an input / output interface 904, and a communication interface 905. The production planning systems 10 and 800 described above are implemented in the computer 900. The above-described functions are stored in the auxiliary storage device 903 in the form of a program. The CPU 901 reads the program from the auxiliary storage device 903, loads it into the main storage device 902, and executes the above-described processing in accordance with the program. The CPU 901 also allocates a storage area in the main storage device 902 in accordance with the program. The CPU 901 also allocates a storage area in the auxiliary storage device 903 for storing data being processed in accordance with the program.

[0035] Alternatively, a program for implementing all or part of the functions of the production planning system 10, 800 may be recorded on a computer-readable recording medium, and the program may be loaded into a computer system and executed to perform processing by each functional unit. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. If a WWW system is used, the term "computer system" also includes a homepage provision environment (or display environment). The term "computer-readable recording medium" refers to portable media such as CDs, DVDs, and USBs, as well as storage devices such as hard disks built into the computer system. If the program is distributed to the computer 900 via a communication line, the computer 900 may load the program into the main storage device 902 and execute the processing described above. The program may be for implementing only part of the functions described above, or may be capable of implementing the functions described above in combination with a program already stored in the computer system.

[0036] Although one embodiment of the present disclosure has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design modifications are possible within the scope of the gist of the present invention. Furthermore, one aspect of the present disclosure may be modified in various ways within the scope of the claims, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. Furthermore, configurations in which elements described in the above embodiments and variations are substituted with elements that achieve the same effect are also included. Furthermore, each embodiment may be combined with other embodiments as appropriate.

[0037] Some or all of the above embodiments can be described as, but are not limited to, the following supplementary notes.

[0038] (Appendix 1) The production planning system comprises: means for classifying a production plan for a product as producible or unproducible based on the expected delivery of parts that make up the product; means for calculating a predicted value of a stockout risk rate, which indicates the ratio of the number of units that can actually be produced to the planned number of units, by analyzing the impact of the number of units that could not be produced due to a shortage of parts on the number of units planned in the production plan for a previously formulated production plan; and means for calculating the number of units that can be considered producible by multiplying the number of units that have been classified as unproducible in the producible or unproducible classification by the predicted value of the stockout risk rate.

[0039] (Appendix 2) The means for classifying the producibility classifies the products that can be produced using the parts whose delivery is confirmed as producible, and classifies the products that are scheduled to be produced using the parts whose delivery is not confirmed as unproducible, in the production planning system described in appendix (1).

[0040] (Appendix 3) The production planning system according to appendix (1) or (2) is one in which the means for calculating the predicted stockout risk rate calculates an average of the past stockout risk rates from actual values ​​of the number of production units that could not be produced due to stockouts of the parts for production plans that were formulated in the past, calculates the stockout risk rate taking into account the impact of periodically occurring stockouts of the parts, and, if an event that affects the stockout of the parts exists, calculates a sudden fluctuation rate that indicates a change in the stockout risk rate due to the event, and calculates a time-series transition of the stockout risk rate based on past performance.

[0041] (Appendix 4) the means for calculating the predicted stockout risk rate arranges the stockout risk rates for each of the production plans formulated in the past in time series, and calculates the slope of a linear equation approximating the transition of the stockout risk rate as the rate of fluctuation of the stockout risk rate; calculates an extension rate from the number of days extended from the delivery date presented by the supplier when ordering parts; arranges the stockout risk rates from the shortest day of the lead time of the parts to the present for each of the production plans formulated in the past in time series, and calculates the slope of the linear equation approximating the transition of the stockout risk rate as the most recent rate of fluctuation; and calculates the predicted value of the stockout risk rate using a linear equation with time as a variable, the sum of the rate of fluctuation of the stockout risk rate, the extension rate, and the most recent rate of fluctuation as the coefficient of the variable, and the sum of the average of the stockout risk rate, the cyclically occurring stockout risk rate, and the sudden rate of fluctuation as constant terms, thereby calculating the transition of the stockout risk rate over time.

[0042] (Appendix 5) The means for calculating the number of units to be produced is the production planning system described in appendix (4), which calculates the number of units to be produced that can be deemed producible by multiplying the stockout risk rate calculated by the linear equation.

[0043] (Appendix 6) This production planning method is executed by a computer and includes the steps of: classifying a production plan for a product as producible or unproducible based on expected deliveries of parts that make up the product; calculating a predicted value of a stockout risk rate, which indicates the ratio of the number of units that can actually be produced to the planned number of units that were produced, by analyzing the impact of the number of units that could not be produced due to a shortage of parts on the number of units that were planned in the production plan that was previously drawn up; and calculating the number of units that can be produced that can be considered producible by multiplying the number of units that were classified as unproducible in the producible or unproducible classification by the predicted value of the stockout risk rate.

[0044] (Appendix 7) This program causes a computer to execute the following steps: classifying a product's production plan into producibility based on expected delivery of parts that make up the product; calculating a predicted value of a stockout risk rate, which indicates the ratio of the number of units that can actually be produced to the planned number of units, by analyzing the impact of the number of units that could not be produced due to a shortage of parts on the number of units planned in the production plan that was previously drawn up; and calculating the number of units that can be produced that can be considered producible by multiplying the number of units that were classified as unproducible in the producibility classification by the predicted value of the stockout risk rate. [Explanation of symbols]

[0045] 1. Required information DB 2. Production information database 3. Production plan calculation section 4. Production planning database 5. Parts availability database 6. Production plan correction section 10. Production planning system 800···Production Planning System 801...Classification means 802...Prediction value calculation means 803....Unit Counting Method 900···Computer 901 CPU 902...Main memory 903...Auxiliary storage device 904 Input / Output Interface 905···Communication Interface

Claims

1. a means for classifying whether a product can be produced or not based on the expected delivery of parts constituting the product in relation to a production plan for the product; a means for calculating a predicted value of a stockout risk rate, which indicates the ratio of the number of units that can actually be produced to the number of units that were planned to be produced in the production plan that was previously drawn up, by analyzing the influence of the number of units that could not be produced due to the stockout of the parts, on the number of units that were planned to be produced in the production plan that was previously drawn up; a means for multiplying the number of units classified as unproducible in the classification of producibility by the predicted value of the stockout risk rate, thereby calculating the number of units that can be considered as producible; A production planning system equipped with:

2. the means for classifying the producibility classifies the products that can be produced using the parts whose delivery is confirmed as producible, and classifies the products that are scheduled to be produced using the parts whose delivery is not confirmed as unproducible. The production planning system according to claim 1 .

3. The means for calculating the predicted stockout risk rate includes: Calculating an average of the past stockout risk rates from the actual number of production units that could not be produced due to the shortage of the parts in the production plans that were formulated in the past, Calculating the stockout risk rate taking into account the influence of periodically occurring stockouts of the parts; If an event that affects the shortage of the part exists, a sudden fluctuation rate indicating a change in the shortage risk rate due to the event is calculated; Calculating a time series transition of the stockout risk rate based on past performance; The production planning system according to claim 1 or 2.

4. The means for calculating the predicted stockout risk rate includes: The stockout risk rate for each of the production plans that have been formulated in the past is arranged in chronological order, and the slope of a linear equation that approximates the transition of the stockout risk rate is calculated as the fluctuation rate of the stockout risk rate; The extension rate is calculated based on the number of days extended from the delivery date presented by the supplier when ordering the parts. The stockout risk rate is arranged in chronological order from the shortest date of the lead time of the part to the present for each of the production plans that were previously drawn up, and the slope of a linear equation that approximates the transition of the stockout risk rate is calculated as the most recent fluctuation rate; The predicted value of the stockout risk rate is calculated using a linear equation in which time is a variable, the sum of the fluctuation rate of the stockout risk rate, the extension rate, and the most recent fluctuation rate is a coefficient of the variable, and the sum of the average of the stockout risk rate, the periodically occurring stockout risk rate, and the sudden fluctuation rate is a constant term, and by calculating a prediction formula for the stockout risk rate, a time series transition of the stockout risk rate is calculated. The production planning system according to claim 3 .

5. The means for calculating the number of units produced is Calculating the number of production units that can be considered producible by multiplying the stockout risk rate calculated by the linear equation. The production planning system according to claim 4.

6. 1. A computer-implemented production planning method, comprising: A step of classifying whether or not a product can be produced based on the expected delivery of parts constituting the product in relation to a production plan for the product; a step of calculating a predicted value of a stockout risk rate, which indicates the ratio of the number of production units that can actually be produced to the number of production units that was planned, by analyzing the influence of the number of production units that could not be produced due to the stockout of the parts, on the number of production units that was planned in the production plan that was made in the past; a step of multiplying the number of production units classified as unproducible in the producibility classification by the predicted value of the stockout risk rate to calculate the number of production units that can be considered as producible; A production planning method comprising:

7. On the computer, A step of classifying whether or not a product can be produced based on the expected delivery of parts constituting the product in relation to a production plan for the product; a step of calculating a predicted value of a stockout risk rate, which indicates the ratio of the number of production units that can actually be produced to the number of production units that was planned, by analyzing the influence of the number of production units that could not be produced due to the stockout of the parts, on the number of production units that was planned in the production plan that was made in the past; a step of multiplying the number of production units classified as unproducible in the producibility classification by the predicted value of the stockout risk rate to calculate the number of production units that can be considered as producible; A program that executes the following.

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