JP4672134B2 - Method and apparatus for managing pallet transfer waiting time in FMS cell - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for managing a pallet conveyance waiting time in an FMS cell, and in particular, a pallet in an FMS cell that appropriately manages the conveyance start time of a workpiece that has been processed by a machine tool to the machine tool in the next process. The present invention relates to a transport wait time management method and apparatus.
[0002]
[Prior art]
FMS (Flexible Manufacturing System) is composed of multiple NC machine tools, pallet transfer devices, pallet storage stations, and computers that control these facilities in an integrated manner. This is a production system.
In this type of FMS cell, pallets loaded with workpieces are sent one after another from the pallet storage station to the machine tool according to a pre-registered schedule, and are automatically processed according to the registered workpiece processing order. To go. In such an FMS cell, unattended operation can be performed at night or the like, so that high productivity can be increased.
[0003]
In the FMS cell, a plurality of machine tools share a series of work processes, and a pallet on which a work that has been processed by one machine tool is moved to a carry-out station of the machine tool, and then transferred to a transfer device. Is transferred to the machine tool in charge of the next process.
[0004]
Conventionally, conveyance of such pallets is managed by a cell controller, and as soon as machining in each machine tool is completed, it is immediately conveyed to the machine tool in the next process so that no wasteful waiting time occurs. .
[0005]
[Problems to be solved by the invention]
However, a machine tool may use a large amount of coolant for cutting depending on the content of processing. Immediately after the processing is completed, a large amount of coolant is attached to the workpiece or accumulated in the processed groove. There may be. Then, the workpiece moves to the unloading station together with the pallet as it is, but when the transport device unloads the pallet, the coolant liquid accumulated on the workpiece may spill and splash around.
[0006]
Further, the workpiece immediately after being machined by the machine tool usually has cutting heat, and thermal expansion occurs. Therefore, if it is transported to the machine tool where the next process is performed immediately after the processing is completed and the setup change operation is performed, the setup is performed with thermal expansion, so that there is an error in setup accuracy and processing accuracy. was there.
[0007]
Therefore, the object of the present invention is to eliminate the problems of the prior art, prevent adverse effects on the surrounding environment due to the splashing of the coolant, and adversely affect the setup accuracy and machining accuracy due to thermal expansion of cutting heat. Pallet transfer waiting time in the FMS cell, which can set and manage an appropriate waiting time when transferring the workpiece to the machine tool in the next process after finishing machining without affecting production efficiency. It is providing the management method and apparatus.
[0008]
[Means for Solving the Problems]
To achieve the above object, the present invention provides a plurality of NC machine tools having a pallet carry-in station and a carry-out station, a pallet storage station, and the NC machine tool designated with a pallet on which a workpiece is placed. And a pallet transfer device that moves in and out of a designated stocker of the pallet storage station, and a method for managing a pallet transfer waiting time in an FMS cell having a production management system that manages these facilities in an integrated manner. for advance each workpiece, the type of individual workpieces out wait upon unloading from the unloading station after the machining end of an NC machine tool to the pallet conveying apparatus and set in accordance with the processing contents, between steps when the setup change of the work is being performed in the said discharge waiting time in the previous step The waiting time between processes from the end of the process to the start of the process on the NC machine tool of the next process is set according to the type of each workpiece and the content of the process. When unloading to the machine, the pallet is made to wait at the unloading station of the NC machine tool until the specified unloading waiting time elapses, and the coolant liquid adhering to the workpiece is removed and collected. The pallet for which the waiting time is set is transferred to the pallet storage station after completion of the unloading waiting time, and waits until the specified waiting time between the processes elapses while cooling the workpiece on the pallet, and then the setup station. transported to, by combining with the discharge waiting time and steps between the waiting time, managing the pallet carrying latency by the pallet conveying apparatus It is an feature.
[0009]
Further, the present invention provides a plurality of NC machine tools having a pallet loading station and a unloading station, a pallet storage station, the NC machine tool designated with a pallet on which a workpiece is placed, and the pallet storage station. A pallet transfer device that moves in and out of a specified stocker, and a pallet transfer waiting time management device in an FMS cell having a production management system that manages these facilities in an integrated manner, and for each workpiece in advance , After the completion of machining in the NC machine tool, when carrying out from the carry-out station to the pallet transfer device, the carry-out waiting time sufficient for removing the coolant liquid adhering to the work piece is determined for each work piece type and the work content. When the workpiece is changed between processes The type of individual workpieces wait time between sufficient steps to cool the workpiece after the unloading standby time ends at the previous step to the start of process of an NC machine tool next step, machining The waiting time setting means that is set according to the contents, and when the NC machine tool that has finished machining is carried out to the NC machine tool of the next process, the pallet is placed in the NC machine until the specified carry-out waiting time elapses. A pallet that has been made to wait at the machine unloading station and that has been set to the waiting time between processes is transferred to the pallet storage station after the unloading waiting time has ended, and is then transferred to the set-up station after waiting for the specified waiting time between processes. And a conveyance control means.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a method and apparatus for managing a pallet transfer waiting time of an FMS cell according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 shows an example of an FMS cell to which a method and apparatus for managing a pallet transfer waiting time of an FMS cell according to the present invention is applied. In this FMS cell, a plurality of NC machine tools (in FIG. 1, five horizontal machining centers) 10a to 10e constitute a machine tool group 10, and these NC machine tools 10a to 10e are used as pallet storage stations. They are arranged in a line along a transfer line 13 provided on the front side of the stocker 12. A setup station 15 is installed on one end side of the transfer line 13. The pallet stocker 12 is a three-dimensional stocker that can store a large number of pallets. The pallet stocker 12 can be loaded into and unloaded from the stocker at a position designated by the transport device 14.
[0011]
FIG. 2 is a block diagram showing a control system of the FMS cell.
The system controller 20 organically links the machine tool group 10 including the NC machine tools 10a to 10e and the transfer device 12 and integrally manages machining according to a production schedule (machining schedule) registered in advance. As a control device, for example, a so-called FA computer is used in which a system is constituted by a personal computer main body and various necessary peripheral devices. This system controller 20 is a CNC device 22 that controls data management functions such as registration, change, display, deletion, and output of machining schedule information and NC machining information, and operations of the NC machine tools 10a to 10e of the machine tool group 10. In addition, there are an operation management function for instructing the start, end, interruption, etc. of the scheduled operation, and an operation control function for controlling the operation of the constituent devices of the FMS cell through the communication line. The system controller 20 and the CNC device 22 of the NC machine tool group 10 are connected via a communication adapter 23 by an optical modem and an optical cable C1. As a result, the system controller 20 can communicate with the CNC device 22 of the NC machine tool group 10.
[0012]
In FIG. 2, reference numeral 24 is a control panel 24 that controls the operation of the transport device 14 and the setup station 15. The control panel 24 is connected to the system controller 20 via the communication adapter 23 by an RS-232C standard communication cable C2.
[0013]
The transport device 14 is directly controlled by the control panel 24, but commands from the system controller 20 are given to the order of loading pallets, designation of pallets to be transported, pallet transport destination, and the like. For example, the transport device 14 takes out a designated pallet from a large number of pallets stored in the pallet stocker 12 and transports the pallet to the setup station 15, or picks up a pallet for which work setup work has been completed at the setup station 15. FMS cell, such as transporting to one of NC machine tools 10a to 10e instructed by the system controller 20, or transporting the processed pallet to the pallet stocker 12 and storing the pallet at the registered position. It is responsible for transporting pallets at all.
[0014]
Next, FIG. 3 is a block diagram showing the configuration of the CNC device 22 that controls the machine tools 10a to 10e. The CNC device 22 includes a PLC device 26 and an NC device 28. The NC device 28 executes a machining program for executing each process of the machining schedule of the FMS cell and performs operations of the machine tools 10a to 10e. The workpiece is subjected to predetermined machining by numerical control.
[0015]
The PLC device 26 is a programmable logic controller, performs sequence control of the NC device 28 and various devices attached thereto in accordance with a sequence program created in advance, and starts and stops the NC machine tools 10a to 10e. A command from the system controller 20 is received and transmitted to the NC device 28, and various information on the NC machine tools 10a to 10e is transmitted to the system controller 20. In FIG. 3, 33 is a loading station for loading the pallet P carried by the conveying device 14 into the machine tool, and 34 is received by the conveying device 14 when the processed pallet P is unloaded from the machine tool. It shows an unloading station that is temporarily waiting for delivery.
[0016]
Next, FIG. 4 is a plan view showing the arrangement of machine tools in the FMS cell to which the present invention is applied. In FIG. 4, two machine tools 10a and 10b are shown, and the others are omitted. For the sake of simplicity, the pallet stocker 12 is shown as No. 1 to No. 10 and each stocker accommodates a single pallet.
[0017]
In FIG. 4, each NC machine tool 10a, 10b has a table 32 disposed on the front side of the machine body. The carry-in station 33 and the carry-out station 34 described above are arranged between the table 32 and the conveyance path 13, and the pallet carried by the conveyance device 14 is first carried into the carry-in station 33.
[0018]
After the pallet is sent from the carry-in station 33 to the inside of the machine tool main body, the PLC device 26 starts a machining operation on the NC machine tool according to a predetermined sequence.
[0019]
That is, the pallet is supplied to the table 32 by a pallet changer (not shown), and when loading of the pallet is completed, the NC machining program is executed. Automatic cutting starts. The processed pallet is discharged to a carry-out station 34 by a pallet changer (not shown), and is then placed on the transfer device 14 and transferred to a machine tool on which next processing is performed.
[0020]
In the present invention, when a pallet that has finished machining a workpiece is transported to an NC machine tool in which the next process is performed, the pallet is made to wait for a preset standby time according to the type of workpiece and the content of machining. ing.
[0021]
FIG. 5 is a process diagram showing a setting example of the processing steps set in the processing schedule in the FMS cell and the waiting time for pallet conveyance.
In the machining schedule shown in FIG. 5, there are four processes from process I to process IV for machining a workpiece, and each process is assigned to different NC machine tools. In each of the steps I to IV, unloading standby times S1 to S4 are set for waiting after the pallet that has been processed is discharged from the table 32 to the unloading station 34. The length of the unloading standby time S1 to S1 is preferably a time sufficient for draining the coolant that has adhered to the workpiece after one step, for example. Further, the length of each of the unloading standby times S1 to S1 can be set individually in consideration of the contents of processing performed in each process.
[0022]
In addition to such unloading standby time, an inter-process standby time is set in the case where a setup change is scheduled between processes. In FIG. 5, for example, inter-process waiting times T1, T2 are set between the process I and the process II and between the process III and the process IV. During this process waiting time T1, T2, the pallet that has finished the previous process in the NC machine tool and moved to the unloading station 34 is further moved to the pallet stocker 12 and stored in the designated stocker. Wait for the passage. When a predetermined time elapses, the pallet is moved to the setup station 15 when the setup change is scheduled, and after the setup operation is performed, the pallet is transported to the NC machine tool where the next process is performed. Further, when the setup change is not scheduled, it is transferred to the NC machine tool where the subsequent process is performed.
[0023]
Such an inter-process standby time is set to a time sufficient to radiate or cool the cutting heat generated by the workpiece by cutting with the machine tool in the previous process. Since the degree of cutting heat borne by the workpiece varies greatly depending on the type and size of the workpiece and the details of the processing, the waiting time between processes is individually set in consideration of these factors. The system controller 20 has a function capable of setting the unloading standby time and the inter-process standby time from the monitor by a simple input operation.
[0024]
FIG. 6 shows an example of an input screen for an inter-process standby time displayed on the monitor screen of the system controller 20.
[0025]
FIG. 6A is an input screen for an inter-process standby time set between process I and process II in FIG. Clicking on the arrow box 100 changes the process number to be set. There is an arrow box in the input box for the setup change. Clicking on this arrow box enables or disables setup change to the next process. When the setup change is set to “Yes” as in the process I, the box below it displays the setup waiting time as the waiting time between the processes, and input the required waiting time in the input box 104 next to it. Can do.
[0026]
On the other hand, FIG. 6B is an input screen when there is no setup change. Assuming that no setup change is planned between Step III and Step IV in FIG. 5, if the input box for setup change is set to “None” on the input screen of Step III, the inter-process standby time is displayed below it. Displayed as machining wait time. In the input box 104 next to the input box 104, a necessary time can be input as a processing waiting time.
[0027]
A similar input screen (not shown) is opened for the transport standby time, and the standby time can be set.
[0028]
FIG. 7 shows a flow of processing in which the system controller 20 manages the waiting time of the pallet when the FMS cell is actually operated after setting the transport standby time and the inter-process standby time in this manner.
[0029]
Hereinafter, the waiting time management in the FMS cell according to the present embodiment will be described with reference to the flowcharts shown in FIGS.
[0030]
First, in FIG. 4, during processing, the pallet that has been set up at the set-up station 15 is sequentially supplied from the pallet P1 to the machine tool 10a sequentially by the transport device 14, for example. The pallet P1 processed by the machine tool 10a is discharged from the machine tool 10a and supplied to the machine tool 10b in order to process the next process. In this way, the pallets P1, P2, P3,... Are sequentially processed by the machine tools 10a, 10b,.
[0031]
Therefore, for example, the process I is performed in the NC machine tool 10a, and the process II is performed in the NC machine tool 10b.
[0032]
In the NC machine tool 10a, when managing the waiting time for the pallet on which the process I is performed, first, when the pallet P5 is loaded into the table 32 of the NC machine tool 10a, the machining by the NC machine tool is performed. Start (step S1). Thereafter, machining proceeds according to the NC machining program. When the processing of the workpiece is finished, the PLC device 26 moves the pallet P5 on which the processed workpiece is placed to the carry-out station 34 (step S3). Then, the PLC device 26 transmits a signal indicating that the processing has been completed to notify the system controller 20 (step S4).
[0033]
When the processing end is notified to the system controller 20 in this way, the system controller 20 checks whether the unloading standby time is set with reference to the standby time registration data (step S5). In the case of the process I, since the unloading standby time S1 is set (yes in step S5), the process proceeds to step S6, the set standby time S1 is set in the timer, and the timer is started. Thereafter, the pallet P5 waits at the carry-out station 34 until the designated waiting time S1 elapses. Accordingly, while waiting, the coolant liquid adhering to or accumulating on the workpiece on the pallet P5 falls and is collected in a coolant receiver (not shown) provided under the carry-out station 34.
[0034]
When the designated standby time has elapsed (Yes in step S7), the process proceeds to step S8, and the system controller 20 refers to the standby time registration data to determine whether or not the inter-process standby time is set. To do. Since the inter-process standby time T1 is set between the process I and the process II (yes in step S8), the process proceeds to step S9. The system controller 20 transmits to the control panel 24 a command for retracting the pallet P5 to the pallet stocker. Thereby, the conveying apparatus 14 carries out the said pallet P5 from the carrying-out station 34, conveys it to the pallet stocker 12, and makes it enter into the No. 5 stocker assigned to this pallet P5. In the process of transporting the pallet, the workpiece on the pallet has already been drained sufficiently, so that it does not scatter around, so that the floor of the FMS cell can be prevented from being contaminated with the coolant. .
[0035]
When the warehousing is completed, the control panel 24 reports the fact that the warehousing is completed to the system controller 20. Then, the system controller 20 sets the standby time to T1 and starts a timer (step S10).
[0036]
Thereafter, the system controller 20 monitors the elapsed time (step S11), and the pallet P5 continues to stand by thereafter. During this waiting time, the work piece with cutting heat can dissipate the heat, so that it is cooled until the waiting time ends. When the waiting time T1 elapses, a command to convey the pallet P5 to the next station scheduled in the machining schedule is transmitted to the control panel 24. The transport device 14 carries out the pallet P5 that has been waiting at the fifth pallet stocker and transports it to the setup station where the setup is scheduled. In this setup operation, the workpiece is cooled and not heated, so that a highly accurate setup change can be performed.
[0037]
If the setup is not scheduled, it is carried into the machine tool where the next process is performed. Even in the cutting in the next process, it is possible to prevent the cutting heat in the previous process from adversely affecting the machining accuracy.
[0038]
The waiting time management has been described above by taking as an example a pallet that has been processed in the process I by the machine tool 10a. However, the pallet waiting time is managed in exactly the same manner by other machine tools. For example, in FIG. 4, in the NC machine tool 10b in which the process II is performed, the pallet P1 that has been processed and moved to the unloading station 34 has no inter-process standby time set before the process III. The coolant liquid is drained while waiting while the unloading waiting time S2 elapses, and is then unloaded to the machine tool where the next step is performed.
[0039]
In addition, since the machining is continued according to the machining schedule in the machine tool group 10 while the unloading waiting time and the waiting waiting time elapse, it is needless to say that the waiting time does not reduce the production efficiency.
[0040]
【The invention's effect】
As is clear from the above description, according to the present invention, the adverse effect on the surrounding environment due to the scattering of the coolant liquid is prevented, and the adverse effect on the setup accuracy and machining accuracy due to the thermal expansion of the cutting heat is prevented, Moreover, it is possible to set and manage an appropriate waiting time when the workpiece is transferred to the machine tool in the next process after the machining is finished without affecting the production efficiency.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of an FMS cell to which a method for managing a pallet conveyance waiting time according to the present invention is applied.
FIG. 2 is a block diagram showing a control system of an FMS cell to which the present invention is applied.
FIG. 3 is a block diagram showing a control unit of a machine tool of an FMS cell.
FIG. 4 is a layout view of an FMS cell to which the present invention is applied.
FIG. 5 is a process diagram showing a setting example of a waiting time for a machining process and pallet conveyance.
FIG. 6 is a diagram showing an example of a standby time setting screen.
FIG. 7 is a flowchart showing a flow of processing for managing a pallet conveyance waiting time according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Machine tool group 12 Pallet stocker 13 Conveyance path 14 Conveyance device 15 Setup station 20 System controller 33 Carry-in station 34 Carry-out station

Claims (2)

A plurality of NC machine tools having a pallet carry-in station and a carry-out station, a pallet storage station, and a pallet on which a workpiece is placed are delivered to the designated NC machine tool and the designated stocker of the pallet storage station. A pallet transfer device for warehousing, and a management method of pallet transfer waiting time in an FMS cell having a production management system for managing these facilities in an integrated manner,
For each workpiece in advance, set the unloading waiting time when unloading from the unloading station to the pallet transfer device after completion of machining in the NC machine tool according to the type of each workpiece and the content of the machining,
When workpiece changeover is performed between processes, the waiting time between processes from the end of the unloading waiting time in the previous process to the start of the process in the NC machine tool of the next process is set as each individual process. Set according to the type of workpiece and details of processing,
When unloading from an NC machine tool that has been processed to the NC machine tool of the next process, the pallet is made to wait at the unloading station of the NC machine tool until the specified unloading waiting time elapses and adheres to the workpiece. Remove and recover the coolant liquid
The pallet for which the inter-process standby time is set is transported to the pallet storage station after the unloading standby time is over and is allowed to wait until the specified inter-process standby time elapses while cooling the workpiece on the pallet. To the setup station,
A method of managing a pallet transfer waiting time in an FMS cell, wherein the pallet transfer waiting time by the pallet transfer device is managed by combining the unloading waiting time and the waiting time between processes. A plurality of NC machine tools having a pallet carry-in station and a carry-out station, a pallet storage station, and a pallet on which a workpiece is placed are delivered to the designated NC machine tool and the designated stocker of the pallet storage station. A pallet transfer device for warehousing, and a pallet transfer waiting time management device in an FMS cell having a production management system for managing these facilities in an integrated manner,
For each work piece, each work has an unloading standby time sufficient to remove the coolant liquid adhering to the work piece when the work piece is carried out from the carry-out station to the pallet transfer device after completion of the machining by the NC machine tool. Set according to the type of material and processing details, and when workpiece setup is changed between processes, after the end of the unloading waiting time in the previous process, A standby time setting means for setting an inter-process standby time sufficient to cool the workpiece until the process starts according to the type of each workpiece and the processing content;
When unloading from an NC machine tool that has been processed to the NC machine tool of the next process, the pallet is made to wait at the unloading station of the NC machine tool until the specified unloading waiting time elapses, and the inter-process standby is performed. The pallet for which the time is set is transported to the pallet storage station after the unloading standby time is finished, and transported to the setup station after waiting for the designated waiting time between processes, and
A pallet transfer waiting time management device in an FMS cell.

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