Numerical Control Device

Abstract

A numerical control device according to one aspect of the present invention is capable of shortening the machining time, and is for controlling a machining device that machines a workpiece with a machining head using a gas, in accordance with a machining program including a plurality of instructions. The numerical control device comprises: a settling time acquisition unit that acquires a settling time required from the start of supplying the gas until the supply state of the gas reaches a required state; a prefetch unit that prefetches the instructions of the machining program; a gas supply decision unit that, on the basis of the instructions prefetched by the prefetch unit, decides a start timing to start supplying the gas so that a specific instruction which requires the supply of the gas is executed after the settling time elapses from the start of supplying the gas; and a gas supply control unit that causes the gas to be supplied to the machining device at the start timing decided by the gas supply decision unit.

Description

[Technical Field]

[0001] The present invention relates to a numerical control device. [Background technology]

[0002] For example, when performing processing such as welding or cutting, it is known to spray an appropriate gas onto the processing point in order to blow away materials or prevent oxidation of the material. It takes a relatively long time for the gas pressure to reach a predetermined pressure compared to the start-up time of processing performed using a laser, electric current, etc. For this reason, in conventional processing, the supply of gas is started after a tool such as a laser head is placed at the processing point, and processing is started after the gas pressure has risen sufficiently.

[0003] Patent Document 1 discloses a technology for shortening processing time and reducing gas consumption by monitoring the rate of increase in gas pressure after gas supply begins, starting the laser before the gas pressure reaches a predetermined pressure, and irradiating the laser immediately after the gas pressure reaches the predetermined pressure. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-68305 Summary of the Invention [Problem to be solved by the invention]

[0005] Although the method described in Patent Document 1 can reduce the waiting time at the processing point, it is desirable to further reduce the processing time. [Means for solving the problem]

[0006] A numerical control device according to one aspect of the present disclosure is a numerical control device that controls a processing device that processes a workpiece using gas with a processing head in accordance with a processing program including a plurality of instructions, and includes: a settling time acquisition unit that acquires the settling time required from the start of gas supply until the gas supply state reaches a required state; a look-ahead unit that looks ahead to the instructions of the processing program; a gas supply determination unit that determines the start timing to start gas supply based on the instructions look-ahead by the look-ahead unit so that a specific instruction that requires gas supply is executed after the settling time has elapsed from the start of gas supply; and a gas supply control unit that causes the processing device to supply gas at the start timing determined by the gas supply determination unit. [Effects of the Invention]

[0007] According to the present disclosure, processing time can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram illustrating a configuration of a numerical control device according to an embodiment of the present disclosure. [Figure 2] 3 is a time chart illustrating the relationship between a machining program and a control output in the numerical control device of FIG. 1; DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Fig. 1 is a block diagram showing the configuration of a numerical control device 1 according to an embodiment of the present disclosure.

[0010] The numerical control device 1 controls a processing device 100. The processing device 100 is a device that processes a workpiece (not shown) using a processing head (not shown) using gas. Examples of processing that the processing device 100 performs include laser welding, laser cutting, arc welding, plasma cutting, gas welding, and gas cutting. In the illustrated embodiment, the processing device 100 is assumed to be a laser processing device that includes a laser head that irradiates a workpiece with a laser as the processing head, a gas nozzle 110 that injects gas into an area to be irradiated with the laser, a servo amplifier 120 that drives multiple motors that move the laser head and the workpiece relative to each other, and a laser oscillator 130 that supplies laser light to the laser head.

[0011] The numerical control device 1 controls the machining device 100 according to a machining program including multiple commands. The numerical control device 1 can be realized by, for example, a computer device having a memory, a processor, an input / output interface, etc., and executing an appropriate control program. The numerical control device 1 includes a settling time memory unit 11, a program memory unit 12, a settling time acquisition unit 13, a look-ahead unit 14, a gas supply determination unit 15, a gas stop determination unit 16, a gas supply control unit 17, a movement determination unit 18, a movement standby setting unit 19, a movement control unit 20, a laser determination unit 21, a laser standby setting unit 22, and a laser control unit 23. Note that these components categorize the functions of the numerical control device 1 related to the present invention and do not necessarily have to be clearly distinguishable in terms of physical configuration and program configuration.

[0012] The settling time storage unit 11 stores the settling time required from the start of gas supply until the gas supply state reaches a required state. The required gas supply state may be, for example, a gas pressure equal to or higher than a target pressure, a gas concentration equal to or higher than a target concentration, etc. A plurality of settling times may be stored corresponding to the type of gas, target pressure, etc., or may be stored as a function of the target value.

[0013] The program storage unit 12 stores a machining program that describes a procedure for machining a workpiece by the machining device 100. The machining program may be written in a programming language such as G-code. The program storage unit 12 may store multiple machining programs.

[0014] The settling time acquisition unit 13 acquires the settling time of the gas used in the processing being performed, that is, reads the settling time from the settling time storage unit 11 and stores it in the working memory.

[0015] The pre-reading unit 14 pre-reads instructions in the machining program. That is, it reads instructions subsequent to the instruction being executed by the machining device 100 from the program storage unit 12 in advance and stores them in the working memory. This allows the numerical control device 1 to determine in advance the subsequent operation schedule of the machining device 100, and to cause the machining device 100 to execute machining according to the machining program without causing delays due to calculations.

[0016] The gas supply determination unit 15 determines the start timing of gas supply so that a command requiring gas supply (hereinafter referred to as a specific command) is executed after a settling time has elapsed since the start of gas supply, based on the command read ahead by the pre-reading unit 14. That is, the gas supply determination unit 15 sets the start timing to a time that is the settling time before the time when execution of the specific command in the machining program is started. The gas supply determination unit 15 also determines the stop timing of gas supply so that the gas supply is stopped simultaneously with the completion of execution of the specific command or after a predetermined delay, based on the command read ahead by the pre-reading unit 14.

[0017] The specific command includes a command to start gas supply, in addition to a command to start machining using gas. In machining programs created for conventional numerical control devices, a command to start gas supply is generally provided immediately before a command to start machining. Therefore, when performing machining based on a conventional machining program, the gas supply determination unit 15 may determine the start timing of gas supply by regarding the command to start gas supply as accompanying a command to start machining. Alternatively, the gas supply determination unit 15 may ignore the command to start gas supply and determine the start timing of gas supply based on the command to start machining. Therefore, a machining program created for the numerical control device 1 may omit the command to start gas supply.

[0018] The start timing may be specified by time or by the position of the processing head. Generally, the processing head is moved to the processing point immediately before processing starts, so the gas supply can also be started appropriately by specifying the position of the processing head corresponding to the start timing from the movement speed for positioning the processing head.

[0019] If the gas supply determination unit 15 cannot ensure the settling time before executing a specific command, for example, if the specific command is issued immediately after the program starts, immediately after the machining conditions are acquired, or immediately after a command to prohibit gas injection, it is not possible to trace back the settling time from the start time of the specific command. In such cases, the gas supply determination unit 15 calculates the shortage time, i.e., the time that can be traced back as far as possible from the start time of the specific command, minus the settling time. Note that the shortage time may be calculated by adding a margin to the simple difference or by multiplying it by a safety factor.

[0020] The gas stop determination unit 16 determines whether to stop the gas supply after the execution of a specific command is completed based on one or more commands following the specific command. Specifically, if the time from the stop timing of the gas supply corresponding to the reference specific command to the start timing of the gas supply corresponding to the next specific command is equal to or less than a predetermined continuation threshold, the gas stop determination unit 16 determines not to stop the gas supply corresponding to the reference specific command but to continue the gas supply continuously until the gas supply corresponding to the next specific command. In other words, the gas stop determination unit 16 corrects the gas supply stop timing in the gas supply schedule determined by the gas supply determination unit 15. Note that the continuation threshold may be zero. Furthermore, if the stop timing of the reference specific command is after the start timing of the next specific command, the gas supply should naturally be continued continuously.

[0021] The gas supply control unit 17 supplies gas to the processing apparatus 100 at the start timing determined by the gas supply determination unit. More specifically, the gas supply control unit 17 controls the gas nozzle 110 according to the schedule determined by the gas supply determination unit 15 and corrected by the gas stop determination unit 16.

[0022] The movement determination unit 18 determines a movement profile of the machining head based on the command pre-read by the pre-read unit 14. Specifically, the movement determination unit 18 calculates the coordinates of the machining head at each time or the position of the drive motor that determines the coordinates.

[0023] Immediately before starting machining, the movement standby setting unit 19 stops the relative movement between the machining head and the workpiece for the shortage time calculated by the gas supply determination unit 15. In other words, the movement standby setting unit 19 corrects the movement profile determined by the movement determination unit 18 so as to delay the start of machining until the gas supply state reaches the required state.

[0024] The movement control unit 20 inputs a command value to the servo amplifier 120 so as to move the machining head relatively in accordance with the profile determined by the movement determination unit 18 and corrected by the movement standby setting unit 19 .

[0025] The laser determination unit 21 determines the profile of the time change in the output setting value of the laser oscillator 130 based on the command read ahead by the read-ahead unit 14.

[0026] Similar to the movement standby setting unit 19, the laser standby setting unit 22 delays the start of laser output immediately before starting processing by the shortage time calculated by the gas supply determination unit 15. In other words, the laser standby setting unit 22 corrects the laser output profile determined by the laser determination unit 21 so as to delay the start of processing until the gas supply state reaches the required state.

[0027] The laser control unit 23 controls the laser oscillator 130 so as to change the laser output in accordance with the profile determined by the laser determination unit 21 and corrected by the laser standby setting unit 22 .

[0028] 2 shows a simplified example of the relationship between the time changes in gas supply, machining head movement, and laser output in the numerical control device 1 as described in the machining program and the time changes in the control output (outputs of the gas supply control unit 17, movement control unit 20, and laser control unit 23). The machining head is programmed to move at high speed during positioning and at low speed during machining. Within the illustrated range, the machining program includes machining of four locations, and between the third and fourth machining operations, a change in machining conditions is made, such as a change in the type or pressure of gas, which requires the gas supply to be stopped.

[0029] In this example of control output, the gas supply for the first and second machining operations begins at a time that is earlier than the start of the machining (head movement and laser output) by the settling time. The gas supply for the third machining operation begins immediately after the gas supply for the second machining operation because the time interval between the second and third machining operations is shorter than the settling time. The gas supply for the fourth machining operation begins immediately after the previous condition change, but because the settling time cannot be ensured at the start time of the machining in the machining program, the start of the machining operation is delayed by the missing time. By using this control output profile, the numerical controller 1 starts laser machining only after the gas supply state reaches the required state, ensuring proper machining.

[0030] Although the embodiments of the present disclosure have been described above, the present invention is not limited to the above-described embodiments. Furthermore, the effects described in the above-described embodiments are merely a list of preferred effects resulting from the present invention, and the effects of the present invention are not limited to those described in the above-described embodiments. For example, a numerical control device according to the present invention may not include a gas stop determination unit, a movement standby setting unit, and a laser standby setting unit. Furthermore, a numerical control device according to the present invention may not include a settling time storage unit and a program storage unit, and the settling time acquisition unit and the look-ahead unit may be configured to acquire information from an external source. [Explanation of symbols]

[0031] 1. Numerical control device 11 Settling time storage section 12 Program memory section 13 Settling time acquisition section 14 Pre-reading part 15 Gas Supply Decision Unit 16 Gas stop determination unit 17 Gas supply control unit 18 Movement decision unit 19 Movement standby setting section 20 Movement control unit 21 Laser determination unit 22 Laser standby setting section 23 Laser control unit 100 Processing equipment 110 Gas Nozzle 120 Servo amplifier 130 Laser Oscillator

Claims

1. A numerical control device that controls a processing device that processes a workpiece using a processing head by utilizing gas in accordance with a processing program including a plurality of instructions, a settling time acquisition unit that acquires a settling time required from the start of gas supply until the gas supply state reaches a required state; a pre-reading unit that pre-reads the commands of the machining program; a gas supply determination unit that determines a start timing for starting the supply of the gas based on the command read ahead by the read-ahead unit so that a specific command requiring the supply of the gas is executed after the settling time has elapsed since the start of the supply of the gas; and a gas supply control unit that causes the gas to be supplied to the processing apparatus at the start timing determined by the gas supply determination unit; a movement standby setting unit that stops the relative movement between the machining head and the workpiece immediately before starting the machining; Equipped with the gas supply determination unit calculates a shortage time when the settling time cannot be secured before the specific command is executed, The movement standby setting unit stops the relative movement between the machining head and the workpiece for the shortage time.

2. The numerical control device according to claim 1 , further comprising a gas stop determination unit that determines whether or not to stop the supply of the gas after the execution of the specific instruction is completed, based on the instruction that follows the specific instruction.

3. The numerical control device according to claim 1 or 2, wherein the specific command is a command to start supplying the gas or to start the machining.

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