JP2013164797A - Power consumption calculation device for machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for calculating power consumption of a machine tool, which does not use an expensive power meter, requires a small amount of data registration and memory, and can more accurately calculate electric power, especially power consumption when the machine is stopped.SOLUTION: Power consumption of an auxiliary device of which start and end of operation are commanded individually is calculated by registering power consumption per unit operation time on memory and multiplying the same by the operation time. Power consumption of auxiliary devices for performing a series of operation by one block of codes is calculated by registering power consumption per a series of operation commanded by the codes on the memory and multiplying the same by the number of times of the commands of the codes. To these power consumption, power consumption of a main device obtained from an NC part and a base power amount consumed at a controller and the like are added, to obtain power consumption of the whole machine.

Description

  The present invention relates to an apparatus for calculating power consumption of a machine tool that performs cutting or grinding of a workpiece (work), and relates to an apparatus for calculating power consumption of equipment operated under the control of an NC apparatus. It is.

  Reducing power consumption to increase demand for energy resources and prevent global warming has become an urgent issue in the field of machine tools, and as part of that, measuring the power consumed by machine tools, It is necessary to manage this.

  The NC device that controls the machine tool includes an axis control unit (NC unit) and an auxiliary device control unit (PC unit). The NC unit controls a spindle motor and a tool feed motor that perform machining of the workpiece itself, and controls the spindle motor and the tool feed motor via a spindle amplifier and a servo amplifier. The PC unit controls operation or stoppage of auxiliary equipment necessary for machining of a workpiece such as a cutting fluid supply device, a tool changer, and a workpiece discharge device. The power consumption of the machine tool is the sum of the power consumed by the device controlled by the NC unit, the power consumed by the device controlled by the PC unit, and the power consumed by the controller itself.

  Of the power consumption of the machine tool, the power consumed by the spindle motor and the tool feed motor controlled by the NC unit varies greatly depending on the machining load. For example, in the case of turning, if the tool cutting depth is increased, both the torque of the spindle motor and the torque of the tool feed motor increase. In the case of milling, when the cutting depth of the tool is increased, the torque of the tool motor increases. Further, if the cutting speed is increased, the amount of power consumption increases due to an increase in the number of rotations of the spindle motor and the tool feed motor. Most of the power consumption of machine tools is consumed by spindle motors that rotate workpieces and tools and servomotors that send tools and moving spindles. The electric power consumed by these motors can be measured by the NC device because the current flowing through these motors is grasped by the spindle amplifier and the servo amplifier.

  The auxiliary operations controlled by the PC section include operations that are performed as a series of operations at a certain timing, such as workpiece loading / unloading, tool replacement, and door opening / closing, as well as cutting fluid and hydraulic oil supply, air flow, and workpiece adsorption. Operation for a certain period of time such as supply of air pressure and discharge of chips. In this specification, the former is called sequential operation and the latter is called continuous operation.

Auxiliary operations such as sequential operations and continuous operation operations are usually commanded by the M code of the machining program. For example, the workpiece discharging operation from the right spindle in a two-spindle opposed lathe is described in one block of M code (for example, M368), and the PC unit that has received this M code operates a plurality of devices sequentially,
(1) Move the workpiece holder from the standby position to the workpiece receiving position.
(2) Move the right headstock to the workpiece delivery position simultaneously with the advancement of the workpiece support arm
(3) Hand lowering of arm tip
(4) Hand open
(5) Right spindle chuck open
(6) Right spindle reverse
(7) Hand rise
(8) Arm retreat
(9) Return the workpiece holder to the standby position
(10) Hand descent
(11) Open the hand (drop the work onto the carry-out conveyor)
(12) Hand lift (return to standby)
A series of operations according to the procedure as described above is executed.

  On the other hand, in the continuous operation operation, a code for instructing the start of operation (for example, M07: start of supply of coolant) and an M code for instructing the end of the operation (for example, M09: stop of coolant) are described in different blocks in the machining program. Is done.

  In addition to the above-mentioned work discharge, the sequential operation includes tool change, automatic door opening and closing (sequential operation with only one operation each), etc. The start / stop of the mist collector and the chip conveyor can be exemplified.

  The PC section controls the operation as exemplified above by controlling the on / off of the power switch of the motor that drives the auxiliary device and the on / off of the solenoid current of the solenoid valve that switches the flow path of the hydraulic oil. The current value flowing through the target device cannot be known. Furthermore, the equipment controlled by the PC unit and its operation are very different depending on the type of machine tool and the specifications required for each machine tool, and the design is often changed by the convenience of the user. It is impossible to measure the power consumption of the auxiliary equipment with the control device.

  Therefore, in order to measure the power consumption of the entire machine tool including the power consumed in the auxiliary operation, it is necessary to install a wattmeter. Patent Document 1 discloses a controller that measures power consumption per unit time and peak power generated at start-up for all actuators installed in a machine in order to avoid an increase in cost due to the installation of the power meter. A timer for accumulating the operation time of each actuator and a counter for accumulating the number of operations are provided, and the power consumption per unit time multiplied by the operation time and the peak power are calculated as the number of operations. The power meter is calculated by calculating the sum of the product and the power consumption of the entire machine by adding the fixed power consumed by the control device and the power of the spindle motor and servo motor. There has been a proposal to measure the power consumption of the entire machine tool without providing it.

JP 2011-170448 A

  As pointed out in Patent Document 1, the installation of a wattmeter increases the cost. On the other hand, with the means proposed in Patent Document 1, the power consumption per unit time or for each operation is registered for all actuators provided in the machine tool, and the number of operations and the operation time are stored for all the actuators. Therefore, there is a problem that the amount of work and memory required for registration is large and processing takes time.

  Therefore, the present invention does not use an expensive wattmeter in the calculation of the power consumption of the machine tool, requires only a small amount of data registration and memory, and further reduces the power consumed by the machine, particularly when the machine is stopped. It is an object to obtain technical means capable of calculating accurately.

  As described above, auxiliary operations of the machine tool that are performed in a short time at a predetermined timing, that is, sequential operations such as workpiece loading / unloading and tool change are usually performed in one block on the machining program. Described in M code. Some M codes that command sequential operation are performed by a single operation of one actuator, such as automatic door opening / closing, but multiple M actuators are operated sequentially by one M code. There are many. On the other hand, the start and end of the cutting fluid and hydraulic oil supply, the temperature converter, and the operation of the chip discharge conveyor are commanded at respective timings on the machining program.

  This invention pays attention to this, and registers the power consumption per unit operation time in the memory for the operation of the cutting fluid pump or the like for which the operation start and end are individually commanded on the machining program. The power consumption is calculated by multiplying the operation time. On the other hand, a series of operations commanded by one block M code etc. in the machining program such as loading / unloading of workpieces is commanded by one code (block). Power consumption per series of operations, that is, even when a plurality of actuators operate sequentially, the amount of power consumed as a whole of the sequential operations is measured and registered in the memory, and the code is commanded by the machining program Each time, the amount of power stored for the code is added. Then, the power consumption of the main equipment such as the spindle motor and feed motor obtained from the NC unit, the power calculated based on the above operation time, and the power calculated based on the number of commands are added together, and further control is performed. The power consumption of the entire machine is to be obtained by adding up the basic power consumption consumed by the machine.

  That is, for each sequential operation commanded from the start to the end of one or a series of operations with one block code, the power is measured in advance for each command unit and registered in the controller. By multiplying the number of commands, the power consumption consumed by the sequential operation as a whole is calculated. Even when a plurality of actuators operate in a series of sequential operations, the power consumption is registered and the number of operations is counted in units of commands, so that there are few arithmetic processes and memory is saved.

  Also, the start and end are commanded in separate blocks such as cutting fluid discharge, air blow for cleaning, cutting fluid and hydraulic fluid temperature converter, hydraulic pump, chip conveyor, mist collector, etc. For those that are continuously operated from the start command to the end command, the power consumption per unit time is measured and registered in advance, and the power consumption is calculated by multiplying the time from start to stop.

  Furthermore, for the basic power consumed by the controller even when the machine is stopped, the power consumption per unit time is measured and registered for each state (mode) such as automatic operation, manual operation, emergency stop state, etc. The constant power consumption is basically calculated by multiplying the operating time for each state.

  As described above, the power consumption of the spindle motor and the tool feed motor that occupy 70 to 80% of the power consumption of the entire machine tool is detected by the NC device. By adding all of the power consumption and the basic power for the continuous operation, the total power consumption consumed by the machine tool can be measured.

  Since there is no need to register unit power consumption and count the number of operations or time the operation time for each of the many actuators provided in the machine tool, the labor required for measurement and registration of unit power consumption is greatly reduced. Thus, the power consumption calculation process can be simplified and the memory can be reduced.

  Further, the power consumed by the controller or the like when the machine power is turned on differs depending on the state of the machine, and the basic power consumption is calculated by dividing it into a plurality of states, so the power consumption can be measured more accurately.

Block diagram of one embodiment of the present invention

  FIG. 1 is a block diagram showing an embodiment of the present invention. The NC device 1 includes an NC unit 2 and a PC unit (controller unit) 3. The NC unit 2 controls the spindle motors 22 through the spindle amplifiers 21. The spindle motors 22 are, for example, spindle motors and rotary tool drive motors, and each motor has a spindle amplifier for the motor. The NC unit 2 also controls servo motors 24... Via servo amplifiers 23. Servo motors 24 are, for example, turret X-axis feed motors and Y-axis feed motors. If there are a plurality of turrets, for each turret, Z-axis, X-axis, Y-axis, B-axis, etc. A necessary number of feed motors are provided, and a servo amplifier is provided for each motor. The NC unit 2 uses a spindle amplifier 21... And a servo amplifier 23... To consume power consumed by the spindle motor 22... And servo motor 24. Is constantly detected, and the power consumption is stored in the main power consumption storage unit 25.

  The PC unit 3 controls motors of various auxiliary devices 32... Provided in the machine tool and solenoid on / off switches 31. The PC unit 3 has a built-in timer 33 to which various sensors 34... Such as a limit switch provided in the machine tool are connected. Sequential operations such as tool change are performed by sequentially operating one or more devices according to the procedure programmed in advance in the PC section when the operation is instructed by the M code. Perform operations such as discharging. When receiving the start command or the stop command for the continuously operating device, the PC unit 3 turns on or off the power switch of the corresponding device. The continuous operation device is continuously operated from on to off.

  The NC device 1 includes an operating power measurement unit 4, an operating power measurement unit 5, and a basic power measurement unit 6. The operating power measuring unit 4 includes a number of unit operating power storage units 41... Corresponding to the types of M codes for sequentially instructing operations, the number of operation counters 42.・ It is equipped with. In the unit operation power storage unit 41..., Power consumed in one sequential operation commanded by the corresponding M code is measured and registered in advance for each sequential operation.

  The operating power measuring unit 5 includes a number of unit operating power storage units 51... Corresponding to the number of devices that are continuously operated, the number of operation timers 52..., And an operating power calculation unit 53. It has. In the unit operating power storage unit 51..., The power consumption per unit operating time of the corresponding device is measured and registered in advance for each device.

  The basic power measuring unit 6 includes a plurality of unit basic power storage units 61... Corresponding to the number of operating states to be switched, in the example of this embodiment, the three types of states of automatic operation mode, manual operation mode, and emergency stop mode. .., And the number of state timers 62... And a basic power calculation unit 63. In each unit basic power storage unit 61..., Basic power consumption per unit time consumed in a state where the machine tool or the power is turned on but all operations are stopped is previously stored in each state. It is measured and registered.

  The NC apparatus 1 includes a block reading unit 11 that reads one block (one line) of a machining program, and a code analysis unit 12 that analyzes a code described in the read block. If the analyzed code is an NC control code, the code analysis unit 12 sends the analyzed command signal to the NC unit 2 to control the spindle motors 22... And the servo motors 24. If the read code is a code that commands an auxiliary operation, the code analysis unit 12 sends the analyzed command signal to the PC unit 3 to control operation / stop of the operation of the auxiliary devices 32.

  Further, when the read code is a code for sequentially instructing an operation, the code analysis unit 12 counts up one operation counter 42 provided corresponding to the code. If the read code is a start command for the continuous operation device, the operation timer 52... Corresponding to the device is started, and if it is a stop command, the operation timer 52. Terminate. The operation timer 52... Counts the operation time for each device.

  The NC device 1 is provided with a main switch 13, a manual automatic changeover switch 14, and an emergency stop switch 15. The manual automatic changeover switch 14 switches the operation state of the machine tool into four states: automatic, energy-saving automatic, manual, and energy-saving manual. One of the state timers 62... Is selected by these switch switching signals, and the state timers 62... Are in the respective states, that is, the automatic operation mode, the energy saving automatic operation mode, the manual operation mode, and the energy saving manual operation mode. The time in emergency stop mode is accumulated and counted. Table 1 shows an example of the on / off state of the control unit corresponding to several devices in each operation mode.

  Due to the difference between the on and off states, the basic power consumed by the controller in each operation mode is different. Therefore, the basic power measurement unit 6 uses the unit basic power consumed in that mode for each operation mode. Is previously measured and stored in the unit basic power storage unit 61..., The operation time in each mode is measured by the state timer 62..., And the two are multiplied to calculate the basic power consumption. It is.

  The operating power calculation unit 43... Adds the power value stored in the unit operating power storage unit 41... To the count value of the operation counter 42. The power consumed by all sequential operations commanded by the unit is obtained. Similarly, the operation power calculation unit 53 sets the operation timer 52... To the power value stored in the unit operation power storage unit 51... For all the auxiliary devices 32 controlled to start / stop by the activation code and the stop code. ······································································································· Similarly, the basic power calculation unit 63... Adds up the power value stored in the unit basic power storage unit 61... By the time value of the state timer 62. Thus, the power consumed by the control device or the like while the main switch of the machine tool is turned on is obtained.

  The total power consumption calculation unit 16 and the display unit 17 provided in the NC device 1 are a main power consumption storage unit 25, an operating power calculation unit 43, an operating power calculation unit 53, and a basic power calculation unit 63. The power consumption stored or calculated is summed and displayed on the display in response to an operator command. In addition, the data transmission unit 18 of the NC device 1 transmits the total power consumption calculated by the total power consumption calculation unit 16 to the management computer in response to a command from the management computer.

  The main power consumption storage unit 25, the operation counter 42 ..., the operation timer 52 ... and the state timer 62 ... are reset simultaneously by a manual command, by a command from the management computer, or at a predetermined timing. Then, a new measurement of power consumption is started. The reset timing is when the operation starts on each day, when the operation starts on the first day of each month, when the work to be processed changes, or when the operation starts for the first time. Since the NC unit counts the number of workpieces to be processed, the power required for processing per workpiece can also be calculated by dividing the total power consumption calculated by the number of workpieces in the measurement period. Can do.

DESCRIPTION OF SYMBOLS 1 Numerical control apparatus 16 Total power consumption calculating part 41 Unit operating power memory | storage part 42 Operation | movement counter 43 Operating power calculating part 51 Unit operating power memory | storage part 52 Operation timer 53 Operating power calculating part 61 Unit basic power memory | storage part 62 State timer 63 Basic power Calculation unit

Claims (3)

A machine tool power consumption calculation device including a numerical controller that sequentially reads blocks described in a machining program and sequentially gives operation commands or operation commands corresponding to the codes of the blocks to the machine tool body,
For each sequential operation described as one block in the machining program, a unit operation power storage unit that stores unit operation power consumed in one sequential operation, and a start block and a stop block are described in the machining program For each continuous operation, a unit operation power storage unit that stores unit operation power consumed per unit time of each continuous operation, an operation counter that counts the number of operations for each sequential operation, An operation timer that measures the operation time for each continuous operation, an operation power calculation unit that calculates an electric energy obtained by multiplying the unit operation electric energy by the count value of the operation counter for each sequential operation, and each continuous operation An operation power calculation unit that calculates the amount of power obtained by multiplying the unit operation power by the time value of the operation timer for each operation. It characterized the door, the power consumption calculation device of the machine tool.   Unit basic power storage unit that stores the unit basic power consumed per unit time in the standby state when the machine tool is turned on and the machine tool is stopped, and the machine tool is turned on. A state timer that measures the elapsed time for each standby mode from when it is shut off to a time, and a basic power calculator that multiplies the unit basic power in each standby mode by the time value of the state timer, The machine tool power consumption calculation apparatus according to claim 1.   Calculate the total power consumption by summing the power consumption measured by the control device, the power consumption calculated by the operating power calculator and the operating power calculator, and the basic power consumption calculated by the basic power calculator. The machine tool power consumption calculation device according to claim 1, further comprising a total power consumption calculation unit.

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