JP5455804B2 - Tool inventory management system - Google Patents

Description

  The present invention relates to a tool inventory management system, and optimally manages a stock of rewritable tools so that necessary machining operations can be reliably performed without unnecessarily holding tools. It has been devised.

  Some tools are rewritable. That is, tools that can be re-polished (recyclable) such as drills and end mills wear their blade surfaces when used, but they can be used again by re-polishing the worn blade surfaces and attaching them. can do. The standard number of times that can be used after re-polishing is determined by the tool.

In production factories, etc., tools are stored in the tool room. When tools are needed at the processing site, the necessary tools are paid out (rented out) from the tool room. I have returned it.
The worn tool that has been returned is re-polished and stored, and the tool that can no longer be used is discarded. If there is a shortage of tools, an order is made to purchase a new tool and the new tool is replenished.

By the way, since the appropriate inventory of the tools stored in the tool room is unknown, there are situations where we have more tools than necessary, and there is a situation where production cannot be performed due to a shortage of tools and production stops. There was a fear.
In addition, although the standard number of times that can be used by re-grinding is fixed, there are some that can be used because of wear earlier than that, others that can be used more than the standard number, and the number of times of use varies. The current situation is that it is difficult to grasp the inventory amount.

For this reason, various tool management systems have been proposed. For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 11-48100), a cassette in which a plurality of tools having the same specifications are stored is managed as one unit, and management such as payout and return is performed. Life prediction) is also done in cassette units.
In other words, tools are managed in units of cassettes, the number of usable tools can be calculated from the cutting tool polishing allowance of each tool and the number of machines per tool, and the date of disposal is predicted by matching with the production plan. A mechanism has been proposed for automatically ordering new tools.
As described above, in the technique of Patent Document 1, tool inventory management is performed in units of cassettes based on the “usable number of times” of the tool.

JP-A-11-48100

By the way, for example, when tools of the same specification are used simultaneously in a plurality of processes, it is necessary to consider not only the number of times the tool can be used but also the number of tools that can be used.
To explain with a simple example, in the case where machining is performed at the same time in the process α and the process β, the process α requires five tools, and the process β requires five tools. In order to perform the processes α and β simultaneously in parallel, ten tools are required.
In this case, the number of times the tool is used is 10, but 10 tools are required.

In the technique of Patent Document 1, since the management is performed only by the number of times the tool can be used, for example, even if the tool can be used 10 times, the tool can be used four times and the tool that can be used six times. If only this tool remains, the processes α and β as described above cannot be performed simultaneously in parallel.
On the other hand, when 10 tools that can be used once remain, the processes α and β as described above can be performed in parallel, but conventionally, the number of usable tools is considered. Because there is no such a judgment.
As a result, when the number of usable tools is insufficient, a necessary number of tools cannot be used simultaneously in a plurality of processes, and there is a problem in that processing work is delayed.

Furthermore, in the management of each cassette, the number of tools stored in one cassette may be large, especially when there is a deadline for the tools to be used (projects, etc.), there will be a situation where many tools remain. there's a possibility that.
More specifically, in a project in which a special device is decided to be manufactured by a predetermined scheduled date, a special (custom) tool is required to process the special device. In this case, if a custom tool is left after the device is completed, the custom tool is not versatile and cannot be used for other purposes and is wasted. On the other hand, if there is a shortage of custom tools in the middle of processing, the equipment cannot be completed by the scheduled date.

  Therefore, inventory management of tools that can be re-polished can be managed not in cassette units but in units of one tool, and even when multiple tools are used in multiple processes at the same time, tool inventory is available. Management is required.

  In view of the above prior art, the present invention is a tool inventory management system capable of optimally managing the inventory of tools that can be reground in consideration of not only the number of usable tools but also the number of usable tools. The purpose is to provide.

The configuration of the present invention for solving the above problems is as follows.
A tool room for storing and storing a tool with a data code having at least tool identification data for identifying and identifying each tool one by one;
Reads a data code attached to a tool that comes out of the tool chamber and is used for processing at the processing site and a tool that is used for processing at the processing site and returns to the tool chamber, and the tool chamber The data code attached to the tool newly accommodated in the tool or the tool discarded from the tool chamber is read, and the tool which is removed from the tool chamber and re-polished in the polishing chamber or re-polished in the polishing chamber A code reader for reading a data code attached to a tool that is returned to the tool chamber after being
Tool management for storing the total number of tools to be managed, as well as determining and storing the number of times each tool is used and the number of regrinding by grasping the movement status of each tool based on the data read by the code reader And
A production management system having as data the number of times the tool is scheduled to be used and the number of tools to be used on each day from the date when machining with the tool is started to the date when machining is terminated;
Stores the order lead time, which is the time from when the order command is issued until the tool is actually delivered, and the standard number of re-polishing, which is the number of times the tool can be used for re-grinding. Tool database,
In each day from the date when machining with the tool is started to the date when machining is finished, the number of times the tool can be used on the day after the order lead time from that date, and the number of times of safety stock on that day, A first inventory forecasting unit that outputs a usage shortage command when the number of usable times on the day after the order lead time falls below the number of safety stocks on the day;
When the use frequency shortage command is issued, a first tool for ordering a number of tools that satisfies the condition that the sum of the number of times the tool can be used and the number of times that the tool to be ordered can be used exceeds the safety stock number A first order command unit that outputs an order command;
In each day from the day when machining with the tool is started to the day when machining is finished, the number of usable tools on the day after the order lead time from the date and the safety stock number on the day are obtained, A second inventory forecasting unit that outputs a command for insufficient number of use when the number of usable items on the day after the order lead time falls below the number of safety stocks on the day;
When the use number shortage command is issued, a second tool for ordering a number of tools that satisfies the condition that the sum of the number of usable tools on the day and the number of usable tools to be ordered exceeds the safety stock number. And a second order command unit that outputs an order command.

The configuration of the present invention is as follows.
The first inventory forecasting part is:
When the safety factor is SF, the order lead time is LT, the number of working days is DY, the number of working days of the tool is NT, and the standard deviation of the number of times of tooling is SDa, the number of times of safety stock SSa on the day is calculated by the following equation:
SSa = SF × [LT × (NT / DY)] ^1/2 × SDa
The number of times that the tool can be used on the day is determined based on the standard number of regrinding of the tool, the total number of tools, and the number of regrinding of the tool,
The number of times the tool can be used on the day after the order lead time, the number of times that the tool can be used on that day, the expected number of times the tool will be used, and the day after the order lead time will be delivered. Calculate based on the number of times new tools are used,
The second inventory forecasting part is:
When the safety factor is SF, the order lead time is LT, the number of working days is DY, the number of working days is NT, and the standard deviation of the number of working tools is SDb, the safety stock number SSb of the day is calculated by the following equation:
SSb = SF × [LT × (NT / DY)] ^1/2 × SDb
The number of usable tools on the day is calculated by dividing the number of usable tools on the day by the numerical value obtained by adding 1 to the average number of remaining regrinding tools on the day,
The order lead time is calculated by dividing the number of times the tool can be used on the day after the order lead time by a value obtained by adding 1 to the average number of remaining regrinding of the tool on the day after the order lead time. It is characterized in that the number of usable tools in a later day is obtained.

According to the present invention, it is possible to eliminate waste caused by management in units of cassettes by managing tools in units of one unit.
In addition, by simultaneously managing inventory based on the number of tool usage and inventory management based on the number of tools used, even if tools are used in multiple processes at the same time, not only the number of tools used but also the number of tools used is required. The tool inventory can be managed to ensure only.
For this reason, it is possible to avoid the conventional problem that “the number of tools becomes insufficient, the tools cannot be used simultaneously in a plurality of processes, and the process is delayed”.

The block diagram which shows the inventory management system of the tool which concerns on the Example of this invention. The characteristic view which shows the state of the frequency | count of usable. The characteristic view which shows the state of the usable number.

  Hereinafter, embodiments of the present invention will be described in detail based on examples.

FIG. 1 is a schematic configuration diagram illustrating a tool inventory management system according to a first embodiment of the present invention.
In the tool chamber 110 shown in the figure, there are a number of tools K1 (X1, X2, X3..., Y1, Y2, Y3..., Z1, Z2, Z3. The tools are collectively referred to as “tool K”.
The tools X1, X2, X3... Are, for example, long drills having the same specifications, and the tools Y1, Y2, Y3... Are, for example, short drills, each having the same specifications. The tools Z1, Z2, Z3... Are, for example, end mills having the same specifications.

  Each tool K is provided with a two-dimensional data code (for example, QR code) and can be read by code readers R1 to R8.

The following data is stored in the two-dimensional data code attached to each tool K.
“Tool individual identification data”, that is, data for identifying and identifying each tool K one by one.
“Tool type data”, for example, data indicating the type of tool, such as a drill or an end mill.
“Standard re-polishing frequency data”, that is, data indicating the standard re-polishing frequency, which is a standard frequency that can be used for processing by re-polishing. For example, when the “standard re-polishing frequency” is 10, it means that the number of times that a new tool can be re-polished and used for machining after being used for machining once is 10 times. . After all, a new tool whose “standard re-polishing number” is 10 times can be used for 11 times in total.
“Tool parameter data”, for example, data indicating tool parameters such as the length of each tool.

Here, the movement state of the tool in this system will be described first.
When a new tool K is purchased and replenished, the above two-dimensional data code is attached to the new tool K, and the attached two-dimensional data code is read by the code reader R1 at the tool chamber entrance. A new tool K is stored and stored in the tool chamber 110.

  When processing at the processing site 120, the tool K used for processing is paid out (rented out) from the tool chamber 110, and the two-dimensional data code attached thereto is read by the code reader R2 at the tool chamber outlet. After that, the tool K is sent to the processing site 120.

  At the processing site 120, the tool K is used to perform the processing, and when the processing is completed, the tool K is read by the code reader R3 at the tool chamber entrance after the two-dimensional data code attached thereto is read out. Returned to 110.

  Among the tools K returned to the tool chamber 110, the unused tools are stored in the tool chamber 110 as they are, and the tool K with severe wear that cannot be used even after re-grinding has a two-dimensional data code attached thereto. After being read by the code reader R4 at the chamber outlet and then discarded, the tool K used for machining exits the tool chamber 110, and the two-dimensional data code attached thereto is read by the code reader R5 at the tool chamber outlet. Further, after being read by the code reader R6 at the entrance of the tool polishing chamber, it is sent to the tool polishing chamber 130.

  In the tool polishing chamber 130, the tool K used for processing is re-polished and bladed. The re-polished tool K is sent to the tool chamber 110 after the two-dimensional data code attached thereto is read by the code reader R7 at the exit of the tool polishing chamber and further read by the code reader R8 at the entrance of the tool chamber. Stored.

  Data read by each of the code readers R1 to R8 arranged at the entrance / exit of the tool chamber 110 and the tool polishing chamber 130 is sent to the tool management unit 200 and stored therein.

The tool management unit 200 temporarily stores the data read by the code readers R1 to R8, and then processes the data so that the total number of tools in consideration of the number of newly purchased and accommodated or the number of discarded tools. Trace the movement path for each tool, identify the location where each tool is currently located, find the status of the tool (location), and the number of times it was used for machining and re-polishing Is counted for each tool.
By performing such data processing, management information for managing the following tools is obtained and stored.
“Inventory amount”, that is, the total amount of tools (total number).
“Tool location”, that is, the status (location location) for each tool indicating where the tool is located (existing) in the tool chamber 110, the processing site 120, or the tool polishing chamber 130.
"Tool usage history", that is, the usage history and the number of uses for each tool.
“Tool re-polishing history”, that is, the history of re-polishing and the number of re-polishing for each tool.

The production management system 300 stores production plan data. The production plan data determines the production (manufacturing) status and number of devices on each day, the time point when the device manufacturing is completed, and the like.
The production plan data includes a date from the date when machining is started using a tool (the date when production is started) to the date when machining is finished (the date when production is finished, that is, the date when the manufacture of equipment is completed). The number of times the tool K of each spec is used (the number of times of use) and the number of the tools K to be used (the number of pieces used) are shown.

  Various data relating to tools are registered in the tool database 400, and necessary data is written by the inventory / order management system 500.

Examples of data registered in the tool database 400 include the following.
・ "Order lead time" for tools set for each spec. The order lead time is the order preparation process and order approval process from the time when an order command is issued to replenish a new tool. Means the time (number of days) until the actual delivery.
For example, for the tool X, the order lead time is “9 days”.
-“Order unit” of tools set for each spec. “Order unit” includes “minimum order quantity” and “reference lot quantity”.
For example, in the case of the tool X, the minimum order number is 10, and the reference lot number is 2. Therefore, with the tool X, it is possible to place an order from the minimum order quantity of 10 or more. For example, when 16 pieces are replenished, the reference lot number (2) is added to the minimum order quantity of 10 pieces. A total of 16 pieces are ordered by adding the number of three sets (that is, 2 × 3 sets = 6 pieces).
・ "Standard re-polishing times" for each spec tool. In the tool X, the standard re-polishing frequency is, for example, 10 times.

Data written in the tool database 400 by the inventory / order management system 500 includes the following.
・ "Actual number of possible re-polishing" for each tool. In the inventory / order management system 500, the actual number of re-polishing times from when a tool is newly delivered until it is discarded based on the tool's re-polishing history and disposal history stored in the tool management unit 200. Ask for. The actual number of regrinsable times may differ from a predetermined standard number of regrindings depending on processing conditions.
• “Actual number of times that each tool can be used”. In the inventory / order management system 500, the actual number of usable times from when a tool is newly delivered until it is discarded is obtained based on the tool usage history and the disposal history stored in the tool management unit 200. . The actual number of usable times may differ from the predetermined standard number of times of use depending on the processing situation. The standard use number is the number of times obtained by adding one to the standard re-polishing number.

  The stock / order management system 500 includes a first stock forecasting unit 510, a second stock forecasting unit 520, a first order processing unit 530, and a second order processing unit 540. These functional units 510 to 540 are functional units that perform specific arithmetic processing realized by incorporating software (programs) into hardware resources (computers).

The first inventory forecasting unit 510 performs a calculation to be described later on the basis of the number of times the tool is used, and obtains the number of times the tool can be used on each day from the calculation date (today) to the day after the order lead time. (Forecast) and the number of safety stocks on the calculation date (today).
Then, when the number of usable times on the day after the order lead time from the calculation date (today) is less than the number of safety stocks, the use number shortage command S1 is output.
Details of the calculation method in the first inventory forecasting unit 510 will be described later.

The second inventory forecasting unit 520 performs a calculation described later on the basis of the number of used tools, and obtains the number of usable tools on each day from the calculation date (today) to the day after the order lead time. (Forecast) and the number of safety stocks on the calculation date (today).
Then, when the usable number on the day after the order lead time from the calculation date (today) is less than the number of safety stocks, the used number shortage command S2 is output.
Details of the calculation method in the second inventory forecasting unit 520 will be described later.

The first order processing unit 530, when the use shortage command S1 is output from the first inventory forecasting unit 510, performs the calculation described later, and calculates “the number of usable tools on the calculation date and the use of the ordered tool”. An ordering command S3 for ordering the number of tools satisfying the condition that the sum of the number of possible times exceeds the number of safety stocks is output.
Details of the calculation method in the first order processing unit 530 will be described later.

When the used quantity shortage command S2 is output from the second inventory forecasting unit 520, the second order processing unit 540 performs the calculation described later, “the number of usable tools on the calculation date and the use of the ordered tool” An ordering command S4 for ordering a number of tools satisfying the condition that the sum of the possible numbers exceeds the number of safety stocks is output.
Details of the calculation method in the second order processing unit 540 will be described later.

  After all, when the number of usable times on the day after the order lead time from the calculation date (today) is less than the number of safety stocks, not only the order command S3 is output, but also the day after the order lead time from the calculation date (today). The ordering command S4 is also output when the number of usable items is less than the number of safety stock items.

  When the order command S3 or the order command S4 is output, the order preparation process and the order approval process are performed in another ordering system (not shown), and then an order is issued to the tool company. For this reason, after the ordering command S3 or the ordering command S4 is output, the ordered number of tools is actually delivered on the day after the ordering lead time.

Next, the calculation method in each function part 510-540 is demonstrated. This calculation is performed daily.
In addition, a tool type of one spec that has not been calculated is selected from a plurality of types of spec tools, the selected tool is calculated, and the commands S1, S2, S3 are selected according to conditions based on the calculation result. , S4 are output.
The remaining specifications of the tools are also calculated sequentially for each type, and commands S1, S2, S3, and S4 are output according to the conditions based on the calculation results.
Since the procedure of the calculation method is the same even if the tool specifications are different, here, a case where the calculation is performed with the tool X selected will be described.

A calculation method in the first inventory forecasting unit 510 will be described below.
First, the first stock forecasting unit 510 obtains the safety stock number SSa on the calculation date (today) using the following equation (1).
Safety stock count SSa = SF × [LT × (NT / DY)] ^1/2 × SDa (1)

In the formula (1), the meaning of each symbol is as follows.
SF is a “safety factor”. For example, the numerical value can be arbitrarily determined based on the safety factor required for the inventory management system, and for example, “1.65” is used. The greater the safety factor, the lower the probability that the tool will be missing.

  LT is “order lead time”, and for tool X, the order lead time is “9 days”. This order lead time is taken from the tool database 400.

DY is the “number of working days” from the day three months before the calculation date (today) to the day six months after the calculation date (today). The number of working days is the date when machining is performed using any tool K including the tool X in the machining site 120 in the three months from the day three months ago to the calculation date (today). The number of working days) and the date on which any tool K including the tool X is scheduled to be used (scheduled working day) in the six months from the calculation date (today) to the day six months later ) Is the number of days added.
The number of working days in the three months can be obtained from the tool usage history stored in the tool management unit 200, that is, the usage history for each tool. The number of working days in the six months can be obtained from the scheduled use date of the tool indicated in the production plan data stored in the production management system 300.

  NT is “the number of days of tool use”, and is the sum of the number of days in which the tool X has been used for machining and the number of days to be used among the above-mentioned working days. For example, even if it is an operating day, there is a day when the tool X is not used (scheduled not to be used). This is the number of days the tool is used.

SDa is “standard deviation of the number of times the tool is used”, and its unit is “number of times”. The standard deviation SDa of the number of times the tool is used is the standard deviation of the number of times the tool X is used on the working day for the three months and the number of times the tool X is scheduled to be used on the scheduled working day for the six months.
The number of times the tool X is used on the working day during the three months can be obtained from the tool usage history stored in the tool management unit 200, that is, the usage history for each tool. The number of times the tool X is scheduled to be used on the scheduled operation date for the six months can be determined from the number of times the tool is scheduled to be used, which is indicated in the production plan data stored in the production management system 300.

  The first inventory forecasting unit 510 further obtains the number of times the tool X can be used on each day from the calculation date (today) to the day after the order lead time (see FIG. 2).

  The number of times the tool X can be used on the calculation date (today) includes the standard number of re-polishing of the tool X stored in the tool database 400, the total number of tools X stored in the tool management unit 200, and the above three. The calculation can be made based on the re-polishing history and the number of re-polishing of the tool X on the working day in months.

For example, when a specific tool X1 is described, if the standard re-polishing number of this tool X1 is 10 and the re-polishing number already performed is 5, the usable number of times of the tool X1 is (standard polishing number 10 times + 1). -(5 times of re-polishing) = 6 times is the usable number of times.
Similarly, the number of usable times of the tools X2, X3,... Is obtained, and the total number of usable times of the tools X1, X2, X3,.

Using the calculation date (today) as a reference, the usable number of times after one to nine days is calculated based on the estimated number of times of use of each tool X indicated in the production plan data stored in the production management system 300 and the calculation date ( It can be calculated on the basis of the number of tools X delivered on each day from 1 day to 9 days after the order is placed before today, and the standard number of re-polishing of the tool X.
For example, when the tool X is not used on the calculation date (today), the number of times the tool X can be used one day after the calculation date (today) is the same as the calculation date (today).
If an ordering command for the tool X is issued 8 days before the calculation date (today) and the ordered tool X is delivered one day after the calculation date (today), the number of usable times two days after the calculation date (today) is To increase. The number of times of use that can be increased is (the number of delivered tools X) × (the number of standard repolishing of the tool X + 1).
When the tool X is used 3 days after the calculation date (today), the number of times the tool X can be used after 4 days from the calculation date (today) decreases.
By performing such calculation, the number of times the tool X can be used is calculated 9 days after the calculation date (today) (that is, the day after the order lead time from the calculation date (today)).

  The first inventory forecasting unit 510 uses the tool X when the number of times the tool X can be used is less than the safety stock number SSa nine days after the calculation date (today) (that is, the day after the order lead time from the calculation date (today)). The shortage number command S1 is output. In the example of FIG. 2, since the number of times the tool X can be used is not less than the safety stock number SSa, the use number shortage command S1 is not output in this case.

Assuming that the use shortage command S1 is output from the first inventory forecasting unit 510, the first order processing unit 530 satisfies the following equation (2), and the order quantity (the number of tools X ordered) = minimum. Calculate the number of orders + (number of reference lots x n).
Number of times the tool can be used on the calculation date + (standard polishing number + 1) × (minimum order number + reference lot number × n)> safety stock number SSa (2)
However, n is an integer of 0 or more.
In the case of the tool X, the standard polishing number is 10, the minimum order number is 10, and the reference lot number is 2.

  Then, when the usage shortage command S1 is output from the first inventory forecasting unit 510, the first order processing unit 530 outputs an order command S3 for ordering the order quantity calculated above.

A calculation method in the second inventory forecasting unit 520 will be described below.
First, the second inventory forecasting unit 520 obtains the safety stock number SSb on the calculation date (today) using the following equation (3).
Number of safety stock SSb = SF × [LT × (NT / DY)] ^1/2 × SDb (3)

In equation (3), the meaning of each symbol is as follows.
SF is a “safety factor”. For example, the numerical value can be arbitrarily determined based on the safety factor required for the inventory management system, and for example, “1.65” is used. The greater the safety factor, the lower the probability that the tool will be missing.

  LT is “order lead time”, and for tool X, the order lead time is “9 days”. This order lead time is taken from the tool database 400.

  DY is the “number of working days” from the day three months before the calculation date (today) to the day six months after the calculation date (today).

  NT is “the number of days of tool use”, and is the sum of the number of days in which the tool X has been used for machining and the number of days to be used among the above-mentioned working days.

SDb is “standard deviation of the number of tools used”, and its unit is “number”. The standard deviation SDb of the number of tools used is the standard deviation of the number of tools X used on the working day for the three months and the number of tools X used on the scheduled working day for the six months.
The number of tools X used on the working day in the above three months can be obtained from the tool usage history stored in the tool management unit 200, that is, the usage history for each tool. The planned number of tools X to be used on the scheduled operation date for the above six months can be obtained from the planned number of tools used indicated in the production plan data stored in the production management system 300.

Next, the second inventory forecasting unit 520 performs the same calculation as that performed by the first inventory forecasting unit 510 and can use the tool X on each day from the calculation date (today) to the day after the order lead time. The number of times is obtained (see FIG. 2).
Further, the second inventory forecasting unit 520 divides the usable number of times of the tool X on each day from the calculation date (today) to the day after the order lead time by (average of the remaining number of regrinding + 1). The number of usable items in each day from the calculation date (today) to the day after the order lead time is calculated. FIG. 3 shows the usable number obtained by calculation.
The “re-polishing remaining number” is the number obtained by subtracting the number of re-polishing (or scheduled to be re-polished) from (standard re-polishing number + 1). This remaining number of re-polishing is the standard re-polishing number of tools, the re-polishing history and re-polishing number of each tool, and the use schedule of the tool indicated in the production plan data stored in the production management system 300 It can be determined from the number of times (that is, the expected number of times of repolishing).

When the used quantity shortage command S2 is output from the second inventory forecasting unit 520, the second order processing unit 540 satisfies the following equation (4): order quantity (number of tools X ordered) = minimum order number + (Reference lot number × n) is calculated.
Number of tools on the calculation date + minimum number of orders + (number of reference lots x n)> number of safety stock SSb (4)
However, n is an integer of 0 or more.
In the case of the tool X, the minimum order number is 10, and the reference lot number is 2.

  The second order processing unit 540 outputs an ordering command S4 for ordering the order quantity calculated as described above, when the usage shortage command S2 is output from the second stock forecasting unit 520.

In Example 1, the standard number of re-polishing was determined in advance for each tool spec. In Example 2, the number of re-polishing of each spec tool was counted and averaged from the tool re-polishing history. “Actual number of usable times” is used in the calculation.
In the first embodiment, the order lead time is determined in advance for each tool spec. In the second embodiment, the actual number of days from when the order command S3 or the order command S4 is output until the actual delivery is returned. The “actual order lead time” obtained in this way is used for the calculation.

DESCRIPTION OF SYMBOLS 110 Tool room 120 Processing site 130 Tool grinding room 200 Tool management part 300 Production management system 400 Tool database 500 Inventory and order management system 510 1st stock forecast part 520 1st order processing part 530 2nd stock forecast part 540 1st 2 order processing department

Claims (2)

A tool room for storing and storing a tool with a data code having at least tool identification data for identifying and identifying each tool one by one;
Reads a data code attached to a tool that comes out of the tool chamber and is used for processing at the processing site and a tool that is used for processing at the processing site and returns to the tool chamber, and the tool chamber The data code attached to the tool newly accommodated in the tool or the tool discarded from the tool chamber is read, and the tool which is removed from the tool chamber and re-polished in the polishing chamber or re-polished in the polishing chamber A code reader for reading a data code attached to a tool that is returned to the tool chamber after being
Tool management for storing the total number of tools to be managed, as well as determining and storing the number of times each tool is used and the number of regrinding by grasping the movement status of each tool based on the data read by the code reader And
A production management system having as data the number of times the tool is scheduled to be used and the number of tools to be used on each day from the date when machining with the tool is started to the date when machining is terminated;
Stores the order lead time, which is the time from when the order command is issued until the tool is actually delivered, and the standard number of re-polishing, which is the number of times the tool can be used for re-grinding. Tool database,
In each day from the date when machining with the tool is started to the date when machining is finished, the number of times the tool can be used on the day after the order lead time from that date, and the number of times of safety stock on that day, A first inventory forecasting unit that outputs a usage shortage command when the number of usable times on the day after the order lead time falls below the number of safety stocks on the day;
When the use frequency shortage command is issued, a first tool for ordering a number of tools that satisfies the condition that the sum of the number of times the tool can be used and the number of times that the tool to be ordered can be used exceeds the safety stock number A first order command unit that outputs an order command;
In each day from the day when machining with the tool is started to the day when machining is finished, the number of usable tools on the day after the order lead time from the date and the safety stock number on the day are obtained, A second inventory forecasting unit that outputs a command for insufficient number of use when the number of usable items on the day after the order lead time falls below the number of safety stocks on the day;
When the use number shortage command is issued, a second tool for ordering a number of tools that satisfies the condition that the sum of the number of usable tools on the day and the number of usable tools to be ordered exceeds the safety stock number. A second order command unit that outputs an order command;
A tool inventory management system comprising: The first inventory forecasting part is:
When the safety factor is SF, the order lead time is LT, the number of working days is DY, the number of working days of the tool is NT, and the standard deviation of the number of times of tooling is SDa, the number of times of safety stock SSa on the day is calculated by the following equation:
SSa = SF × [LT × (NT / DY)] ^1/2 × SDa
The number of times that the tool can be used on the day is determined based on the standard number of regrinding of the tool, the total number of tools, and the number of regrinding of the tool,
The number of times the tool can be used on the day after the order lead time, the number of times that the tool can be used on that day, the expected number of times the tool will be used, and the day after the order lead time will be delivered. Calculate based on the number of times new tools are used,
The second inventory forecasting part is:
When the safety factor is SF, the order lead time is LT, the number of working days is DY, the number of working days is NT, and the standard deviation of the number of working tools is SDb, the safety stock number SSb of the day is calculated by the following equation:
SSb = SF × [LT × (NT / DY)] ^1/2 × SDb
The number of usable tools on the day is calculated by dividing the number of usable tools on the day by the numerical value obtained by adding 1 to the average number of remaining regrinding tools on the day,
The order lead time is calculated by dividing the number of times the tool can be used on the day after the order lead time by a value obtained by adding 1 to the average number of remaining regrinding of the tool on the day after the order lead time. A tool inventory management system characterized by obtaining the number of usable tools at a later date.

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