Chip recovery system

Abstract

To provide a chip recovery system capable of preventing a decrease in production efficiency and easily recovering chips at a low cost.SOLUTION: A chip recovery system S includes: a chip storage container 3; a chip amount detector 4; a chip amount monitoring unit 14; and a database 11 for storing a plurality of predetermined chip recovery scheduled times, an NC program, and the like; an expected chip amount calculation unit 13 for calculating an expected chip amount for each NC program; and a recovery determination unit 16 for determining whether or not chip recovery at each chip collection scheduled time is necessary. The recovery determination unit 16 is configured to: add, when the chip recovery scheduled time arrives, a chip amount detected by the chip amount detector 4 and the chip amount monitoring part 14 and the expected chip amount calculated by the expected chip amount calculation unit 13 based on the NC program used until reaching a next chip collection scheduled time: compare an added value with a chip amount threshold; and determine, when the added value exceeds the chip amount threshold, that recovery of chips at the reached chip recovery scheduled time is necessary.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a system for collecting chips generated during machining by a machine tool. [Background Art]

[0002] In the cutting processing performed by machine tools in production plants, materials scraped off from workpieces are generally collected from the machine tool directly or via a chip conveyor into a chip storage container such as a chip bucket or a chip receiver. If chips collected in the chip storage container overflow the container, they will scatter on the plant floor, causing deterioration of the plant environment. Therefore, generally, workers check the amount of chips in the chip storage container periodically or when the container is deemed full, collect the chips stored in the container, and empty the container to prevent chips from overflowing. On the other hand, techniques have already been disclosed to solve the problem that conveyed chips scatter on the plant floor if the chip conveyor is operating during chip collection. For example, Patent Document 1 discloses a technique in which a chute with a shutter is provided at a lower portion of a discharge port of a chip conveyor, and when the amount of chips reaches a predetermined amount, an automated guided vehicle collects the chip storage container, and the shutter closes during collection to prevent chips from scattering onto the plant floor. Furthermore, efficient chip collection is required at production sites. For example, Patent Document 2 discloses a technique of connectable chip storage containers, which describes that a collection route for a cart is determined based on the time when the container will be full calculated from the chip discharge amount set for each machine. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2021-166260 [Patent Document 2] Japanese Patent No. 5473120 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] In conventional methods, when chips are collected periodically, they are collected even if there is not enough chip accumulation in the chip storage container, resulting in wasted collection time and reduced production efficiency. However, according to the invention of Patent Document 1, since there is a means for monitoring the amount of chips, it is possible to collect the chips when they have accumulated sufficiently in the chip storage container, thereby preventing a decrease in production efficiency. The invention of Patent Document 2 also assumes that the chips will be collected when the chip storage container is full, so efficient chip collection can be performed with little effort and in a short amount of time. However, because automated guided vehicles (AGVs) are used to collect containers and carts that have accumulated a large amount of chips, electricity consumption increases, leading to higher costs. On the other hand, manually collecting heavy containers and carts would place a heavy burden on workers.

[0005] Therefore, the purpose of this disclosure is to provide a chip recovery system that prevents a decrease in production efficiency and also enables inexpensive chip recovery. [Means for solving the problem]

[0006] To achieve the above objective, this disclosure provides a chip recovery system comprising a chip storage container for receiving chips generated by machining in a machine tool, A chip quantity detection means for detecting the amount of chips accumulated in the chip storage container, A storage means for storing a plurality of predetermined scheduled chip collection times, which are the timings for collecting the chip storage container or collecting chips from the chip storage container; an NC program to be used for machining; a scheduled time for using the NC program; and a chip quantity threshold for determining whether chip collection is necessary. A chip quantity calculation means calculates the expected chip quantity, which is the amount of chips expected to be generated during processing, for each NC program, The system includes a collection determination means for determining whether or not it is necessary to collect chips at each of the scheduled chip collection times, The collection determination means, upon reaching the scheduled chip collection time, adds up the amount of chips detected by the chip amount detection means and the estimated amount of chips calculated by the estimated chip amount calculation means based on the NC program to be used until the next scheduled chip collection time, compares the added value with the chip amount threshold, and determines that chip collection is necessary at the reached scheduled chip collection time if the added value exceeds the chip amount threshold. Another aspect of the present disclosure is characterized in that, in the above configuration, the predicted chip amount calculation means calculates the predicted chip amount based on past chip amounts detected by the chip amount detection means when the NC program was used in the past, or on chip amounts calculated by simulation using the NC program. Another aspect of this disclosure is that, in the above configuration, the storage means stores the operating time of the NC program used for machining and the average spindle load during operation. The predicted chip amount calculation means, when calculating the predicted chip amount based on the past chip amount, and when the past chip amount is not stored in the storage means for the NC program to be used, is characterized in that it calculates the predicted chip amount based on the ratio of the multiplicative value of the operating time and the average spindle load for the NC program to be used to the sum of the multiplicative values ​​of the operating time and the average spindle load for each NC program that operated during the past scheduled chip collection time, and the amount of chips produced by the operation of all the NC programs detected by the chip amount detection means during the past scheduled chip collection time. Another aspect of the present disclosure is a chip transport device for transporting chips from the machine tool to the chip storage container, in the above configuration, The system further comprises a conveying device control unit that controls the chip conveying device, The conveying device control unit is characterized by stopping the chip conveying device at the scheduled chip collection time, and stopping the chip conveying device when the amount of chips detected by the chip amount detection means exceeds the chip amount threshold. [Effects of the Invention]

[0007] According to this disclosure, production efficiency will be improved by eliminating unnecessary chip collection and chip quantity verification work. Furthermore, since the chip collection method is not limited to automated guided vehicles (AGVs), it is possible to operate the system at a lower cost than introducing AGVs. In addition, since a chip quantity threshold can be set to determine whether or not chip collection is necessary, if manual collection is performed, it can be considered in consultation with the worker's physical ability, making it possible for anyone to collect the chips. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing the mechanical configuration of the chip recovery system. [Figure 2] This is a functional block diagram of the chip recovery system. [Figure 3] This is a flowchart for the operation control of the chip collection system. [Figure 4] This is a flowchart for the operation control of the chip collection system. [Figure 5] This is a flowchart for calculating the expected amount of chips. [Modes for carrying out the invention]

[0009] The embodiments of this disclosure will be described below with reference to the drawings. Figure 1 shows an example of a mechanical configuration diagram of a chip recovery system S. The machine tool 1 is equipped with a chip transport device 2. The chips discharged from the chip transport device 2 are accumulated in a chip storage container 3, which is in the form of a chip bucket, located below the chip discharge port of the chip transport device 2. The chip storage container 3 is equipped with a chip volume detector 4. The chip volume detector 4 monitors the amount of chips in the chip storage container 3, and when it is determined that chip collection is necessary at a pre-set chip collection scheduled time, the chip collection means 5 collects the chip storage container 3. In this embodiment, the chip collection means 5 is an automated guided vehicle. In this embodiment, the chip volume refers to the weight of the chips, but it is desirable that the volume can also be detected.

[0010] Figure 2 shows an example of a functional block diagram of the chip recovery system S. The chip recovery system S comprises a database 11, a transport timing derivation unit 12, a predicted chip volume calculation unit 13, a chip volume monitoring unit 14, a transport device control unit 15, a recovery decision unit 16, and a production management system 17. Database 11 stores the NC programs used for production, the operating time of each NC program, the expected amount of chips generated by the operation of each NC program, the average spindle load during the operation of each NC program, the planned time for using each NC program in the production process, the planned time for collecting chips from the chip storage container 3, the conveyor rotation time required for the conveyor of the chip transport device 2 to complete one rotation inside the machine tool 1, a chip volume threshold used to determine whether chips will overflow from the chip storage container 3, and past production records. Past production records include the amount of chips generated in past production, NC program history, past NC program operation time, past NC program average spindle load, and past chip collection time. The predicted chip amount, NC program operation time, and NC program average spindle load are values ​​recorded or stored from past production records. The scheduled time for using the NC program in the production process, the scheduled time for chip collection, the conveyor rotation time, and the chip volume threshold are all preset values. Database 11 is an example of the storage means of this disclosure.

[0011] The conveying timing input unit 12 determines the operation timing and stopping timing of the chip conveying device 2 with the aim of preventing chips from falling onto the factory floor during chip collection. The operation timing of the chip conveying device 2 is determined by subtracting the conveyor rotation time from the scheduled chip collection time. The stopping timing is determined by the scheduled chip collection time. The predicted chip volume calculation unit 13 calculates the predicted chip volume generated by each NC program. The predicted chip volume is calculated based on past production performance. The predicted chip volume calculation unit 13 is an example of the predicted chip volume calculation means of this disclosure. The chip amount monitoring unit 14 measures the amount of chips accumulated in the chip storage container 3 by the chip amount detector 4 provided in the chip storage container 3, and determines whether the chip amount exceeds the chip amount threshold stored in the database 11. The chip amount detector 4 and the chip amount monitoring unit 14 are an example of the chip amount detection means of the present disclosure. The conveying device control unit 15 controls the chip conveying device 2 based on the operation timing and stop timing of the chip conveying device 2 and the determination result of the chip amount monitoring unit 14. The collection determination unit 16 compares the chip amount threshold in the database 11 with the sum of the chip amount in the chip storage container 3 at the scheduled chip collection time and the expected chip amount of the NC program that will operate before the next scheduled chip collection time after the current scheduled chip collection time, and determines whether chip collection is necessary. The collection determination unit 16 is an example of the collection determination means of the present disclosure.

[0012] The database 11 is constructed by being created on a dedicated server installed in the factory or by a method via the Internet such as a cloud service. The conveyance timing deriving unit 12, the expected chip amount calculation unit 13, the chip amount monitoring unit 14, the conveyance device control unit 15, and the collection determination unit 16 are constructed in the NC device 10 of the machine tool 1. The NC device 10 includes a CPU and a memory connected to the CPU, through which the operation control of the machine tool 1 and the chip collection system S is realized. However, part or all of these functional units may be constructed in a computer provided outside the machine tool 1. The production management system 17 monitors and records the operation status and chip collection status of the chip conveyors 2 and the NC devices 10 in the entire factory.

[0013] Hereinafter, the operation control of the chip collection system S will be described based on the flowcharts of FIG. 3 and FIG. 4. This operation control is executed by a program stored in a non-transitory computer-readable storage medium including a memory connected to the CPU of the NC device 10. First, in step (hereinafter referred to as "S")-1, access to the database 11 is performed, and the scheduled chip collection time and the conveyor rotation time are acquired. Next, in S-2, the conveying timing derivation unit 12 derives and sets the time obtained by subtracting the conveyor rotation time from the scheduled chip collection time as the operating timing of the chip conveying device 2, and the scheduled chip collection time as the stopping timing of the chip conveying device 2. Next, in S-3, the predicted chip volume calculation unit 13 calculates the predicted chip volume. Details of this calculation will be described later. Next, once production begins in S-4, the NC program scheduled for S-5 starts.

[0014] Next, in S-6, once it is confirmed that the timing for operating the chip transport device 2, which was set in S-2, is reached, the chip transport device 2 is activated in S-7. Next, while the chip transport device 2 is operating, in S-8, the chip volume monitoring unit 14 determines whether the amount of chips in the chip storage container 3 exceeds the chip volume threshold. If it is determined that the amount of chips exceeds the chip volume threshold, an error is issued in S-9 to stop the chip transport device 2, and the error is recorded in the production management system 17 to notify the relevant parties. At this point, the chip storage container 3 may be collected by the chip collection means 5. On the other hand, if the chip volume does not exceed the chip volume threshold as determined in S-8, then in S-10, it is determined whether it is time for the chip transporter 2 to stop, i.e., the scheduled chip collection time. If it is not yet time for the chip transporter 2 to stop, the process returns to S-8 and loops from S-8 to S-10 until it is time for the chip transporter 2 to stop. Then, when it is time for the chip transporter 2 to stop, S-11 stops the chip transporter 2.

[0015] Subsequently, in S-12, the NC program history executed from S-5 to S-11, the operating time of each NC program, the current amount of chips in the chip storage container 3, and the average spindle load of the NC programs are recorded in the database 11 as past production performance. Once recording is complete, in S-13, the recovery determination unit 16 acquires the current amount of chips accumulated in the chip storage container 3, in S-14 predicts the NC program that will run until the next scheduled chip recovery time, in S-15 the predicted chip amount calculated by the predicted chip amount calculation unit 13 based on the predicted NC program is added together with the current amount of chips accumulated in the chip storage container 3, and in S-16 the sum is compared with the chip amount threshold in the database 11. If the sum is below the chip volume threshold, chip recovery is deemed unnecessary. In S-17, the information that chip recovery is unnecessary is recorded in the production management system 17 and notified to the chip recovery means 5. On the other hand, if the sum is equal to or greater than the chip volume threshold, chip recovery is deemed necessary. In S-18, the information that chip recovery is necessary is recorded in the production management system 17 and notified to the chip recovery means 5 to perform recovery. Subsequently, in S-19, it is determined whether there are still NC programs scheduled to run. If there are NC programs, the process returns to S-5. If there are no NC programs, production ends in S-20.

[0016] The estimated chip volume calculated in S-3 is a value derived from past production performance. Specifically, it is calculated by determining the ratio of the product of the operating time of the NC program that ran during each chip collection time in the past and the average spindle load, and then multiplying the total chip volume during each chip collection time by this ratio. This calculation method is explained based on the flowchart in Figure 5. First, S-31 accesses database 11 to obtain NC program information to be used for production planning. Next, in S-32, select an NC program that does not calculate the expected chip volume in the flowchart, and in S-33, set the variable N in the flowchart to 1. Next, in S-34, it is determined whether there are any unconfirmed chip collection times between the previous chip collection time and the next (meaning the one after the previous one) chip collection time stored in database 11 when the selected NC program was running. If the existence of an unconfirmed chip collection time is confirmed, in S-35, the expected amount of chips at the unconfirmed chip collection time is calculated. The calculation formula is shown below.

[0017] Let NCa (1 ≤ a ≤ A (A ≥ 1)) be the NC program that ran between the previous chip collection time and the next chip collection time, Ta be the running time of the NC program, Fa be the average spindle load during the NC program's operation, and W be the total amount of chips generated by all NC programs that ran between the previous chip collection time and the next chip collection time. Then, calculate the expected amount of chips Wa at this chip collection time based on NCa as follows.

[0018]

number

[0019] Once the calculation is complete, in S-36, 1 is added to N, and in S-37, it is checked whether there are any unconfirmed chip collection times for the selected NC program. If there are still unconfirmed chip collection times, the process returns to S-34. If there are no unconfirmed chip collection times, in S-38, the average value of Wa, Wa', is calculated using the following formula, and this is taken as the estimated chip volume by NCa.

[0020]

number

[0021] Next, in S-39, the system checks whether there are any other NC programs that have not been selected. If there are any unselected NC programs, it returns to S32; otherwise, it terminates the calculation in S-40. If no unconfirmed chip collection times exist in S-34, proceed to S-39. Even if an NC program that does not calculate the expected chip volume in S-32 is selected, if there are no unconfirmed chip collection times in S-34, the expected chip volume will be the past chip volume detected between scheduled chip collection times in that NC program.

[0022] The chip recovery system S in the above configuration includes a chip storage container 3 for receiving chips generated by machining in a machine tool 1, a chip amount detector 4 and a chip amount monitoring unit 14 for detecting the amount of chips accumulated in the chip storage container 3, and a database 11 that stores a plurality of predetermined chip recovery scheduled times which are the timing for recovering the chip storage container 3, an NC program used for machining, the scheduled time for using the NC program, and a chip amount threshold for determining whether chip recovery is necessary. Furthermore, the chip recovery system S includes a chip amount calculation unit 13 that calculates the expected chip amount for each NC program, and a recovery determination unit 16 that determines whether or not chip recovery is necessary at each scheduled chip recovery time. Then, when the scheduled chip collection time is reached, the collection determination unit 16 adds up the amount of chips detected by the chip amount detector 4 and the chip amount monitoring unit 14 and the expected amount of chips calculated by the expected chip amount calculation unit 13 based on the NC program to be used until the next scheduled chip collection time is reached. The unit then compares this sum with the chip amount threshold and determines that chip collection is necessary at the reached scheduled chip collection time if the sum exceeds the chip amount threshold.

[0023] This configuration improves production efficiency by eliminating unnecessary chip collection and chip volume checks. Furthermore, since chip collection is not limited to automated guided vehicles (AGVs), the system can be operated at a lower cost than introducing AGVs. In addition, a chip volume threshold can be set to determine whether chip collection is necessary, so if manual collection is performed, it can be adjusted according to the physical capabilities of the worker, making it possible for anyone to collect the chips.

[0024] The predicted chip volume calculation unit 13 calculates the predicted chip volume based on the chip volume calculated from past chip volumes detected by the chip volume detector 4 and the chip volume monitoring unit 14 when the NC program was used in the past. Therefore, it is possible to calculate an accurate predicted chip volume based on past production results. When the predicted chip volume calculation unit 13 calculates the predicted chip volume based on past chip volumes, and when past chip volumes are not stored in the database 11 for the NC program to be used, it calculates the predicted chip volume Wa based on the ratio of the product of the operating time Ta and average spindle load Fa for the NC program to be used to the sum of the product of the operating time Ta and average spindle load Fa for all NC programs that operated between past scheduled chip collection times, and the amount of chips W produced by the operation of all NC programs detected by the chip volume detector 4 and the chip volume monitoring unit 14 between past scheduled chip collection times. Therefore, the expected chip volume Wa can be easily calculated based on the NC program's operating time Ta and the average spindle load Fa.

[0025] The system further includes a chip transport device 2 that transports chips from the machine tool 1 to the chip storage container 3, and a transport device control unit 15 that controls the chip transport device 2. The transport device control unit 15 controls the chip transport device 2 to stop at the scheduled chip collection time, and also stops the chip transport device 2 when the amount of chips detected by the chip amount detector 4 and the chip amount monitoring unit 14 exceeds a chip amount threshold. This effectively prevents chips from falling onto the factory floor during chip collection.

[0026] In the above configuration, a chip transport device and a chip storage container in the form of a chip bucket are provided, but it is sufficient that the chips discharged from the machine tool are stored in some kind of container with a chip volume monitoring mechanism. In other words, the chip storage container may be a container such as a chip receiver that directly receives the chips, and the presence or absence of a chip transport device is not required. The information recorded in the database is not limited to the format described above; additional information may be added as needed. There may be multiple databases, for example, both inside and outside the factory. In the above embodiment, the expected chip volume was calculated by calculating the ratio of the product of the operating time of the NC program that ran between each past scheduled chip collection time and the average spindle load, and multiplying the total chip volume generated by the operation of all NC programs by this ratio. However, in this disclosure, the method of calculating the expected chip volume is not limited as long as it is a value calculated by using the NC program. For example, it may be calculated based on the measured value of the chip volume generated by using the NC program as in the above embodiment, or it may be calculated based on the chip volume calculated by a simulation using the NC program. Furthermore, although the calculation of the expected chip volume was performed before production in the above embodiment, the calculation of the expected chip volume may be performed each time during production.

[0027] If a chip transport device is provided, the calculation method for the operation timing and stopping timing of the chip transport device is not specified, as long as the control does not transport chips during the chip collection operation from the chip storage container. In the above configuration, the chip collection means is an automated guided vehicle, but it may also be a worker carrying a communication device, for example, as long as they can receive notification from the collection decision means regarding the necessity of collection, and the form is not limited. The collection of chips is not limited to the above configuration in which the chip storage container is collected, but may also be a configuration in which the chips are collected on the spot from the chip storage container. There may be multiple NC programs running between scheduled chip collection times, or even if there is only one NC program, the need for chip collection can be determined for that specific NC program. [Explanation of Symbols]

[0028] S... Chip recovery system, 1... Machine tool, 2... Chip conveying device, 3... Chip storage container, 4... Chip quantity detector, 5... Chip recovery means, 11... Database, 12... Conveying timing input unit, 13... Predicted chip quantity calculation unit, 14... Chip quantity monitoring unit, 15... Conveying device control unit, 16... Recovery decision unit, 17... Production management system.

Claims

1. A chip collection container for receiving chips generated during machining in a machine tool, A chip quantity detection means for detecting the amount of chips accumulated in the chip storage container, A storage means for storing a plurality of predetermined scheduled chip collection times, which are the timings for retrieving the chip storage container or retrieving chips from the chip storage container; an NC program to be used for machining; a scheduled time for using the NC program; and a chip quantity threshold for determining whether chip collection is necessary. A chip quantity calculation means calculates the expected chip quantity, which is the amount of chips expected to be generated during processing, for each NC program, The system includes a collection determination means for determining whether or not it is necessary to collect chips at each of the scheduled chip collection times, The chip recovery system is characterized in that, when the scheduled chip recovery time is reached, the recovery determination means adds up the amount of chips detected by the chip amount detection means and the estimated amount of chips calculated by the estimated chip amount calculation means based on the NC program to be used until the next scheduled chip recovery time is reached, compares the added value with the chip amount threshold, and determines that chip recovery is necessary at the reached scheduled chip recovery time if the added value exceeds the chip amount threshold.

2. The chip recovery system according to claim 1, characterized in that the predicted chip amount calculation means calculates the predicted chip amount based on past chip amounts detected by the chip amount detection means when the NC program was used in the past, or chip amounts calculated by simulation using the NC program.

3. The storage means stores the operating time of the NC program used for machining and the average spindle load during operation. The chip recovery system according to claim 2, wherein the predicted chip amount calculation means calculates the predicted chip amount based on the past chip amount, and if the past chip amount is not stored in the storage means for the NC program to be used, the predicted chip amount is calculated based on the ratio of the multiplicative value of the operating time and the average spindle load for the NC program to be used to the sum of the multiplicative values ​​of the operating time and the average spindle load for each NC program that operated during the past scheduled chip recovery time, and the amount of chips produced by the operation of all the NC programs detected by the chip amount detection means during the past scheduled chip recovery time.

4. A chip conveying device for conveying chips from the machine tool to the chip storage container, The system further comprises a conveying device control unit that controls the chip conveying device, The chip recovery system according to any one of claims 1 to 3, characterized in that the conveying device control unit stops the chip conveying device at the scheduled chip recovery time, and stops the chip conveying device when the amount of chips detected by the chip amount detection means exceeds the chip amount threshold.

Images