JPH04300099A - Method and device for controlling machine tool of press machine, and the like - Google Patents

Abstract

PURPOSE:To discriminate the reference position or the moving state of the bottom dead center, etc., of the moving body and to surely control by utilizing the interference measure of length with the laser beam for the measure of the motion distance of the moving body of the die, etc. CONSTITUTION:When the laser beam is oscillated from the laser oscillator 1 parallel with the drive of the press machine, and irradiates the laser beam is divided to the reference light 14 and the light 15 to be measured with the beam splitter 16 of the interference device 10 of the optical system 2. The light 15 to be measured is reflected parallel to the light 15 to be measured through the right angle reflecting mirror 12 attached to the lower die 21, as the reflecting light to be measured 18 at the corner cube 17 provided on the upper die 23, the direction is changed through the right angle reflecting mirror 12, the interference light 19 is made by being composed with the reference light 14 whose direction is changed at the beam slitter again through the corner cube 13. Before composing, the half of the reflecting light to be measured 18 is divided to two beams having the phase difference at the wave length plate 11, changed to the optical signal with phase difference, so the advance of the moving body can be distinguished.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a control method and apparatus for a machine tool such as a press machine, and more specifically, for example, the position of a moving point such as the bottom dead center of a moving body such as an upper mold in a press machine. The present invention relates to a method and device for controlling machine tools such as presses that perform linear motion, which makes it possible to easily measure and control machine tools and produce processed products with little variation in quality.

0002

[Prior art] Conventionally, for example, "bending" was performed using a press machine.
When performing plastic processing such as drawing, the optimum processing conditions are assumed by setting the bottom dead center of a moving object such as a processing tool such as a mold, and based on feedback from the quality of the prototype product after processing. The reference position such as bottom dead center is changed or corrected, and control is performed to the reference position.

However, during operation of machine tools such as presses, displacement may occur in the reference position due to changes over time, rapid temperature changes, and the like. In such a case,
The actual bottom dead center position during machining is measured, and if the amount of displacement is greater than a certain value, the displacement is adjusted and mechanically corrected to a preset reference bottom dead center position.

By the way, a proximity sensor such as an eddy current sensor is usually used to measure the displacement of the bottom dead center position of a moving body.

[0005]

[Problems to be Solved by the Invention] However, the above configuration has the following problems. That is, (1) In order to accurately measure the bottom dead center position, the measurement point must be set at the tip surface of a processing tool such as an upper metal fitting, which limits the mounting location of a sensor or the like. ■Due to the short measurement range (approximately 1 mm), changes in the fully dynamic process during operation cannot be ascertained. That is, it is not possible to grasp the influence of the vibration state of machining tools such as molds and machines, and the stopping position of upper molds and the like when the machine is stopped. ■ The impact on product quality due to abnormalities in the machine itself cannot be monitored. ■ It is impossible to predict the effects of wear and service life of machining tools such as molds. ■ It is not possible to grasp the load on machining tools such as molds and the machine itself while the machine is in operation. There are other problems.

[0006] Therefore, as a result of various research studies regarding the above-mentioned points, the present inventor utilized the principle of a laser interferometric length measuring machine to measure the motion of a moving body such as an upper mold of a machine tool such as a press machine. We have found that the above-mentioned problems can be resolved by doing so. That is, a typical laser interferometric length measuring machine (configuration using two frequencies), as shown in FIG.
The light to be measured is divided into a reference signal and the light to be measured, the light to be measured is split into the light to be measured and the reference light by a deflection prism c, and the light to be measured is reflected by a moving reflecting mirror (corner cube) d, and the Doppler effect The reference light is reflected by a fixed reflecting mirror (corner cube) e and interferes with the measured light, and the interference light (fringe) is converted into a length by an arithmetic circuit f, and the distance traveled is calculated by It is designed to be able to measure.

[0007] In the case of this laser interferometric length measuring machine, the moving distance changes only at a certain wavelength, and a peak of intensity change appears repeatedly each time, and precise distance measurement can be performed by counting these peaks. It can be said that accurate distance measurement can be similarly performed by disposing a movable reflector on the moving body of a machine tool.

The present invention was devised in response to the above-mentioned points, and its purpose is to easily measure the position of a moving body such as an upper mold during the entire movement, and to perform all continuous machining. It is an object of the present invention to provide a control method and apparatus for a machine tool such as a press machine, which allows checking the fluctuation state of the processing load during a process and easily controls the moving body to the optimum motion condition.

[0009]

[Means for Solving the Problems] As a means for solving the above problems, the method of controlling a machine tool such as a press machine of the present invention uses interferometric length measurement using a laser beam to Measure the locus of motion under load and the locus of motion when no load is applied to a movable body such as an upper die facing a fixed body, compare the two loci of motion, and determine the standards such as bottom dead center during actual machining of the movable body. It consists of a configuration that controls the position and state of movement.

In addition, another method of controlling a machine tool such as a press machine according to the present invention is based on a reference such as the bottom dead center of a movable body such as an upper die facing a fixed body such as a lower die in a machine tool such as a press machine. A method for controlling the position and motion state, which uses interferometric length measurement using a laser beam to measure the reference motion trajectory of the moving body under load and the motion trajectory when no load is applied, and calculates both motion trajectories. , obtain the machining load amount and use it as the reference machining load amount, measure the motion trajectory of the moving body during actual machining, and compare it with the motion trajectory when no load is applied to obtain the actual machining load amount.
By comparing the reference machining load amount and the actual machining load amount, the reference position such as the bottom dead center of the movable body and the motion state are controlled. Here, another press machine control method of the present invention includes a configuration in which the processing load amount is detected by the acceleration of the moving body in the above configuration.

Furthermore, the control device for a machine tool such as a press machine according to the present invention can be used to control the reference position such as the bottom dead center of a movable body such as an upper die facing a fixed body such as a lower die in a machine tool such as a press machine. A device for controlling the motion state, which includes a laser oscillation unit that oscillates and irradiates a main light beam, and a laser beam irradiated from the laser oscillation unit that is divided into a reference light and a measured light, The light is reflected through a fixed reflecting mirror provided on a fixed body of the press machine and onto a movable reflecting mirror provided on a moving body, and a reflected light to be measured is obtained via the fixed reflecting mirror, and the reflected light to be measured and the reflected light to be measured are an optical system unit that interferes with the reference light; an interference light detection unit that detects the interference light between the reflected light to be measured and the reference light by the optical system unit and obtains a detection signal; and an interference light detection unit that obtains a detection signal; - A length measurement calculation section that measures the position or motion trajectory of the moving body by counting the converted detection signals. Here, the control device for a machine tool such as a press machine of the present invention includes:
In the above configuration, there is provided a load calculation unit that calculates the load during press processing from measurement data from the length measurement calculation unit, and the load data obtained by the length measurement calculation unit is used to determine a reference point such as the bottom dead center of the moving body. It also includes a configuration having a control unit that controls the position and movement state.

0012

[Operation] The method and device for controlling machine tools such as press machines of the present invention uses interferometric length measurement using a laser beam to measure the movement distance of a moving object such as a mold, thereby achieving more precise measurement. Since the movement position of the moving body is detected during all machining processes, the entire motion trajectory of the movable body can be obtained, so the machining load during all continuous machining processes of the movable body can be measured. This function allows the user to check the state of fluctuation in the moving body, and to easily control the moving body to the optimum condition.

As described above, the method and apparatus for controlling a machine tool such as a press according to the present invention utilizes interferometric length measurement using a laser beam to measure the moving position of a moving body of a machine tool such as a press. This feature provides a special function in that the reference position such as the bottom dead center of the moving body and the state of movement can be determined and the control can be performed accurately and reliably.

[0014]

Embodiments Hereinafter, embodiments embodying the present invention will be described with reference to the drawings. Here, FIGS. 1 to 4 are
An embodiment of the present invention is shown in which FIG. 1 is a schematic configuration diagram of a control device, FIG. 2 is an explanatory diagram of a movement trajectory of a moving body assumed when no load is applied, and FIG. 3 is a movement trajectory of a moving body during actual machining. FIG. 4 is an explanatory diagram of the machining load amount.

This embodiment is a control device for a press machine, and roughly speaking, it includes a laser oscillation section 1, an optical system section 2, a press main body section 3, an interference light detection section 4, a length measurement calculation section 5, and a processing load. It is composed of seven parts: a calculation section 6 and a control section 7.

The laser oscillation section 1 is composed of a laser oscillator 8 and an oscillation power supply 9. Here, a He-Ne laser oscillator is used as the laser oscillator 8, and is configured to oscillate and irradiate a laser beam. The oscillated and irradiated laser beam then enters the optical system section 2.

The optical system section 2 is composed of an interferometer 10, a wavelength plate 11, a right-angle reflecting mirror 12, and a corner cube 13. The interferometer 10 includes a beam splitter 16 that splits a laser beam oscillated and irradiated by the laser oscillation unit 1 into a reference beam 14 and a measured beam 15, and a corner cube 17 that is a fixed reflecting mirror. The interferometer 10 then reflects the light to be measured 15 via the right-angle reflecting mirror 12 on a corner cube 13 which is a moving reflecting mirror, and passes through the wavelength plate 11 via the right-angled reflecting mirror 12 as reflected light to be measured 18. It is arranged so that it is combined with the reference light 14 to form interference light 19, which is detected by the interference light detection section 4.

The press body 3 has a press bolster 20 and a lower die 21 forming a fixed body, and a press slider 22 and an upper die 23 forming a moving body. The right angle reflecting mirror 12 of the optical system section 2 is placed in the lower mold 21.
However, a corner cube 13 is also attached to the upper mold 23. That is, the right-angle reflecting mirror 12 is attached to the lower mold 21 so that the measured light 15 that has exited the interferometer 10 is incident at a predetermined angle (45 degrees) and is reflected toward the corner cube 13. The cube 13 is attached to the upper mold 23 so as to be located on the optical path of the light to be measured 15 from the right-angle reflecting mirror 12.

The interference light detection section 4 is constituted by a photoreceptor that receives interference light (fringes). In addition, the length measurement calculation section 5
It is composed of an up-down counter 24 and a distance calculation circuit 25, and the up-down counter 24 converts the signal received by the interference light detection unit 4 into the motion trajectory of the moving object (upper mold 21) and the peak in the drive range. In addition to counting and storing the number of hours, the distance calculation circuit 25 also uses the up-down counter 2 using the wavelength of the laser beam as a measurement standard.
The configuration is such that the distance can be calculated and converted based on the count value in step 4. In addition, the machining load calculation unit 6
Based on the measurement data obtained by the length measurement calculating section 5 and since the acceleration is proportional to the displacement of the moving point, the machining load (actual load) is calculated using the acceleration of the moving point. Furthermore, the control unit 7 calculates the machining load (actual load) data during machining obtained by the machining load calculation unit 6 and the optimum machining load amount and maximum machining load value for various materials and machining methods stored in advance. The structure is such that the moving body's motion speed, bottom dead center position, etc. can be corrected and controlled by comparing the data with reference machining load data and if there is a difference between the two.

Next, a control method will be explained using the press machine control device of the above-described embodiment. First, the control unit 7 is made to store reference machining load data obtained by setting in advance the material to be pressed and the machining method. The reference machining load data is obtained by obtaining the motion trajectory of the moving object under no load (see Figure 2) and the motion trajectory assuming a load (during machining) (see Figure 3), and calculating from both motion trajectories. The acceleration of the moving body is calculated to obtain the machining load amount (see FIG. 4), and reference data consisting of this machining load amount (area A of the machining load) is determined. The reference data may be calculated or may be data obtained by actually operating the press.

[0021] Then, the material to be pressed is placed in a predetermined position, and plastic working is performed in the same manner as in the usual case. That is, the press slider 22 is driven to move the upper die 23, and the material is pressed with the lower die 21 provided on the press bolster 20.

Here, in parallel with the driving of the press machine, when a laser beam is emitted and irradiated from the laser oscillation section 1, the laser beam is converted into a reference beam 14 by the beam splitter 16 of the interferometer 10 in the optical system section 2. and the light to be measured 15,
The light to be measured 15 passes through the right angle reflector 12 mounted to the lower mold 21 and is reflected by the corner cube 17 mounted on the upper mold 23 as reflected light 18 to be measured.
It is reflected parallel to , is changed direction via the right-angle reflector 12 , and is again directed by the beam splitter 16 of the interferometer 10 .
The interference light 19 combined with the reference light 14 whose direction has been changed via the corner cube (fixed) 13 is received by the light receiving body of the interference light detection section 3 .

Note that before the reflected light 18 to be measured is combined with the reference light 14, half of the reflected light 18 to be measured is split into two beams having a phase difference by a wavelength plate 11, and the reflected light 18 is divided into two beams having a phase difference.
and is converted into an optical signal with a phase difference by two photoelectric elements. This signal is emitted when the corner cube 17 attached to the moving body (upper mold 23) moves every λ/4, and the traveling direction of the moving body can be determined based on the phase difference.

The signal from the interference light detection unit 3 is counted by the up/down counter 24 in the length measurement calculation unit 5, and the signal is counted by the up/down counter 24 in the length measurement calculation unit 5, and the signal is counted by the up/down counter 24 in the length measurement calculation unit 5, and the signal is counted by the up/down counter 24 in the length measurement calculation unit 5, and the motion trajectory of the moving body (upper die 23) of the press machine and the peak time in the drive range are calculated. The count number of is memorized,
In addition, the length measurement calculation circuit 25 calculates the distance between the moving object and the fixed object based on the count value of the up-down counter 24 using the laser wavelength as a measurement standard, and the motion trajectory under load as shown in FIG. 3 is calculated. can get. This measurement data is then sent to the machining load calculation unit 6, where it is compared with a pre-stored motion trajectory at no-load (see Fig. 2), and the actual machining load amount (see Fig. 4) is calculated. . In principle, these data are based on one cycle of processing,
For example, comparison is made using the distance from top dead center to top dead center as a reference.

Now, to explain the motion trajectory, in FIG. 3, the beginning of departure from the same motion trajectory as when no load is applied indicates the start of actual machining, and the peak bottom dead center position indicates the end of machining. Further, in FIG. 4, the area A generated by the deviation of the motion trajectory from the start to the end of machining and its trajectory indicate the machining load situation during machining. Therefore,
The actual machining situation can be grasped from the motion trajectory of the moving body and the machining load amount.

Furthermore, the machining load (actual load) data during machining obtained by the machining load calculation unit 6 is used in the control unit 7 to calculate the optimum machining load amount and maximum machining load for various materials and machining methods stored in advance. The data is compared with standard machining load data consisting of data such as values, and if there is a discrepancy between the two, the motion speed and bottom dead center position of the moving object are corrected and controlled based on the preset standard machining load data. .

By the way, the machining load amount A and the motion trajectory depend on the bottom dead center position, the thickness of the material to be processed, the material, the processing method (cutting, bending, drawing, cutting, etc.), vibration, temperature, speed of the linear moving body, etc. Varies depending on Therefore, if a change occurs in the detected motion trajectory or processing load amount, the moving body will be adjusted immediately. According to this embodiment, the relationship between the moving object and the fixed object can be measured as a continuous motion trajectory with the distance as the vertical axis and the time as the horizontal axis, and the fluctuation can be determined by comparing with preset reference data. When a change occurs, it acts so that the change can be detected immediately.

[0028] Furthermore, compared to the conventional example, the following effects are achieved. That is, (1) it is not necessary to measure the tip of the moving body (processing tool such as a mold), which is the actual bottom dead center, so there are extremely few restrictions on the mounting location. ■ The effects of vibrations from the machine itself can be removed, allowing for a higher level of quality assurance. - The measurement range can be expanded from the conventional approximately 1 mm to approximately 200 mm, so it can respond to a wide range of changes in the thickness of the workpiece. ■ Displacement due to the influence of temperature on the press itself, processing tools such as molds, and the workpiece is corrected. ■ The position of molds, etc. can be grasped during the entire process when the machine is stopped or started. ■ It becomes possible to monitor damage to processing tools such as molds and abnormalities in the press itself during operation. ■ By monitoring long-term machining load fluctuations, it is possible to predict the lifespan of machining tools such as molds. ■ Since the actual processing load can be grasped, predictive diagnosis of press machine failures is possible.

It should be noted that the present invention is not limited to the above-described embodiments, but includes modifications that can be made without departing from the gist of the present invention. Incidentally, in the above-mentioned embodiments, a press machine was explained, but it goes without saying that other machine tools can be similarly implemented. Further, the configuration of the radar interferometric length measuring device is not limited to this configuration, and may be other configurations. Furthermore, the reflecting mirror may be attached to the movable body or the fixed body, not to the mold, but to the main body of a press machine or machine tool to which the mold is mounted.

[0030]

Effects of the Invention As is clear from the above explanation, according to the control method and apparatus for a machine tool such as a press machine of the present invention, interference by a laser beam can be avoided in measuring the moving position of a moving body of a machine tool such as a press machine. By using length measurement, the reference position such as the bottom dead center of the moving object and the state of motion can be easily determined, and by detecting fluctuations in the reference position and state of movement, its control can be performed accurately and reliably. This has the effect that it can be done.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a control device showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a motion trajectory of a moving body assumed when there is no load.

FIG. 3 is an explanatory diagram of a motion trajectory of a moving body during actual machining.

FIG. 4 is an explanatory diagram of processing load amount.

FIG. 5 is a schematic configuration diagram of a laser interferometric length measuring device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Laser oscillation part, 2... Optical system part, 3... Press machine main body part, 4... Interference light detection part, 5... Length measurement calculation part, 6... Machining load calculation Part, 7... Control part, 8.
... Laser oscillator, 9... Power source for oscillation, 10... Interferometer, 11... Wave plate, 12... Right angle reflecting mirror, 13
...Corner cube, 14...Reference light, 15...
・Measurement light, 16...Beam splitter, 17...
・Corner cube, 18... Reflected light to be measured, 19・
...Interference light, 20...Press machine bolster, 21...
・Lower mold, 22...Press machine slider, 23...
Upper mold, 24...Up-down counter, 25...
・Distance calculation circuit

Claims (5)

[Claims] Claim 1: Utilizing interferometric length measurement using a laser beam, the locus of motion under load and the locus of motion under no load of a movable body such as an upper die facing a fixed body such as a lower die are measured, and both A method for controlling a machine tool such as a press machine, comprising comparing motion trajectories and controlling a reference position such as a bottom dead center and a motion state during actual machining of the movable body. 2. A method for controlling the reference position such as the bottom dead center and the movement state of a moving body such as an upper die facing a fixed body such as a lower die in a machine tool such as a press machine, the method comprising:
Using interferometric length measurement with a beam, measure a reference motion trajectory under load and a motion trajectory under no load of the moving body, compare the two motion trajectories, obtain a machining load amount, and use it as a reference machining load amount;
We also measure the motion trajectory of the moving object during actual machining,
The actual machining load amount is obtained by comparing the above-mentioned no-load motion trajectory, and by comparing the above-mentioned standard machining load amount and the actual machining load amount, the reference position such as the bottom dead center of the moving body, the movement state, etc. A control method for a machine tool such as a press machine, characterized by controlling a machine tool such as a press machine. 3. The method of controlling a machine tool such as a press machine according to claim 2, wherein the processing load amount is detected by the acceleration of the moving body. 4. A device for controlling the reference position such as the bottom dead center and the movement state of a moving body such as an upper die facing a fixed body such as a lower die in a machine tool such as a press machine, the device comprising: A laser oscillation unit that oscillates and irradiates a beam, a fixed reflecting mirror that divides the laser beam irradiated from the laser oscillation unit into a reference beam and a measured light, and that transmits the measured light to a fixed body of the press machine. an optical system unit that reflects the reflected light to a movable reflecting mirror provided on a moving body through the fixed reflecting mirror, obtains the reflected light to be measured via the fixed reflecting mirror, and causes the reflected light to be measured and the reference light to interfere with each other; An interference light detection unit detects the interference light between the reflected light to be measured and the reference light by the system unit to obtain a detection signal, and the interference light detection unit detects and obtains a detection signal.
A control device for a machine tool such as a press machine, comprising a length measurement calculation section that counts converted detection signals to obtain the position or motion trajectory of the moving body. 5. A processing load calculation unit that calculates the load during press working from measurement data from the length measurement calculation unit, and a reference position such as the bottom dead center of the moving body and the like based on the load data obtained by the length measurement calculation unit. 5. The control device for a machine tool such as a press machine according to claim 4, further comprising a control section that controls a motion state.