JP6363421B2 - Work seating determination method and apparatus - Google Patents

Description

  The present invention relates to a workpiece seating determination method and apparatus.

  Conventionally, Patent Documents 1 and 2 disclose a seating determination method in which the degree of adhesion of a workpiece to a seating surface and the presence or absence of the workpiece in a machine tool / molding machine or the like is detected with high accuracy by air.

  Fixing the workpiece to the machining table without gaps is indispensable to maintain machining accuracy, but it is ideal to make the gaps zero, but it does not fall within chips or cutting oil generated during machining. It is not realistic to make the gap zero due to the influence of the included chips.

  Therefore, it is necessary to detect that the gap is equal to or less than a predetermined numerical value by a sensor or the like, and back pressure sensors are used as shown in Patent Documents 1 and 2 above.

JP 2010-54413 A Japanese Utility Model Publication No. 63-115776

  However, in the conventional method and apparatus for determining the seating of a workpiece, it takes a long time to reach the pass / fail determination line in the air pressure value (back pressure) of the workpiece sitting, and there is a problem that the determination time is long. Furthermore, since the pressure sensor used has a hysteresis (hysteresis), there is a problem in that pressure detection becomes unstable and so-called chattering occurs if the gap at the time of sitting and the gap at the time of machining are made the same. In Patent Document 1, a 2-port solenoid valve that shuts off the supply air is provided and a pressure sensor is provided on the secondary side so that a change in back pressure is detected and a seating distance is determined in a short time. Yes.

  However, even if the gap when the workpiece is seated on the machining table can be detected, when detecting the gap during subsequent workpiece machining, the two-port solenoid valve is turned on each time the air pressure value is detected. -It must be detected by turning it OFF, and the 2-port solenoid valve is frequently turned ON / OFF, which permanently impedes the solenoid valve and cannot be continuously detected.

  In addition, in order to maintain machining accuracy, when the “gap during machining” when the workpiece leaves the machining table is used as a standard, there is a hysteresis, which is stricter (narrower) than the standard for seating. If the same “criterion at the time of machining” is applied to the criterion of “clearance at time”, an abnormal signal may be generated even within the gap range that satisfies the original seating regulations. This phenomenon is called a “chocolate stop”, and the problem is that the machining operation is interrupted each time and the work efficiency is lowered. The workpiece seating determination method and apparatus according to the present invention have been proposed in order to solve such problems.

  The gist for achieving the object by solving the above-described problems of the workpiece seating determination method and apparatus according to the present invention is based on the back pressure of the air supplied when the workpiece is seated on the table and during machining. The seating determination method for determining whether or not the workpiece is in a seated state, wherein the seating pass / failure at the time of the seating is determined by stopping the supply air by a solenoid valve using a solenoid valve when the workpiece is seated on a table. Is measured and compared with a change in back pressure set in advance by the control device, and whether or not the seating at the time of processing is accepted or not is determined by supplying air to the solenoid valve by the control device. Control is performed by setting a back pressure set at the time of workpiece machining as a threshold value, and comparing the back pressure of the threshold value with the measured back pressure by the control device, and determining pass / fail.

  Also, the gist of the workpiece seating determination method according to the present invention is to determine whether or not the workpiece seating state is acceptable based on the back pressure of the air supplied when the workpiece is seated on the table and during machining. Whether the seating is successful or not is determined in advance by the control device by measuring the change in the back pressure by stopping the supply air by the solenoid valve by the control device when the work is seated on the table. Pass / fail judgment is made in comparison with the change in the back pressure, and whether the seating is accepted or not during the machining is controlled by the control device so that supply air is supplied to the solenoid valve. Successively measured by a pressure sensor connected to the control device, and the control device compares the change in the back pressure drop with a change in the back pressure drop determined to be a preset work separation gap. To do .

  The gist for solving the above-mentioned problems of the workpiece seating determination device according to the present invention and achieving the object of the invention is to provide a detection orifice of a table for discharging supply air to the workpiece, and a pipe for supplying air to the detection orifice. , A pressure sensor connected to the pipe, a two-port solenoid valve connected to the pipe for controlling supply / stop of air, and valve opening / closing control and data connected to the pressure sensor and the two-port solenoid valve, respectively. And a control device for setting air pressure connected to the pipe, and by back pressure of air supplied at the time of sitting on the table of the workpiece and at the time of processing A seating determination device for determining whether or not the workpiece is seated. The seating determination at the time of the seating is based on whether the supply air is supplied by a solenoid valve by the control device when the workpiece is seated on the table. Stop and measure the change in the back pressure, and pass / fail judgment by comparing with the change in the back pressure set in advance by the control device. The back pressure set at the time of workpiece machining is set as a threshold value, and the back pressure measured by the pressure sensor is compared with the back pressure by the control device to determine pass / fail.

  Further, the gist of the workpiece seating determination device according to the present invention includes a detection orifice for discharging supply air to the workpiece, a pipe for supplying air to the detection orifice, a pressure sensor connected to the pipe, and the pipe. A 2-port solenoid valve connected to control supply / stop of air; a control device connected to each of the pressure sensor and 2-port solenoid valve to control valve opening / closing and data input / output; and connected to the pipe. A seating determination device for determining whether the workpiece is seated or not by back pressure of air supplied when the workpiece is seated on the table and during machining. When the seat is seated on the table, the control device is configured to measure the change in the back pressure by stopping the supply air using a solenoid valve by the control device. Pass / fail judgment is made in comparison with the change in the back pressure set in advance, and the acceptance / non-acceptance of the seating at the time of machining is controlled by the control device so as to supply supply air, and is set at the time of workpiece machining. The back pressure is set as a threshold, and the back pressure measured by the pressure sensor is compared with the back pressure measured by the pressure sensor and the pass / fail judgment is made.

  According to the workpiece seating determination method and apparatus of the present invention, not only when the workpiece is seated, but also during workpiece machining, the back pressure is measured and the seated state is always maintained, regardless of the durability of the solenoid valve. Will be able to monitor.

  According to the seating determination method according to the present invention, the back pressure is measured by a pressure sensor and compared with a threshold value, so that the chattering as in the conventional example is generated by setting the same clearance between the seating time and the processing time, Or the occurrence of “choco stop” can be prevented in the present invention.

  In addition, by measuring the back pressure, grasping the drop in the back pressure as a slope, and comparing it with the slope of the set value, an excellent effect of shortening the detection time is obtained.

It is a perspective view which shows the partial schematic structure of the use condition based on the Example of the seating determination apparatus 7 of the workpiece | work which concerns on this invention. It is a block diagram of the workpiece | work seating determination apparatus 7 of the same invention. It is sectional drawing of the supply air control part A in the seating determination apparatus 7 of the workpiece | work. It is a time chart figure in the seating determination method of the work. It is a schematic block diagram of the calibration which calculates | requires the relationship between a back pressure and a clearance gap. It is a characteristic curve figure which shows the relationship between the back pressure and time T at the time of seating of a workpiece | work.

  As shown in FIG. 1, the workpiece seating determination method and apparatus according to the present invention uses a pressure sensor to perform seating judgment not only when the workpiece is seated but also during machining. .

  As shown in FIGS. 1 to 2-A, a workpiece seating determination device 7 according to the present invention includes a detection orifice 5 of a table 9 that discharges supply air to a workpiece (detected object, hereinafter the same), and the detection. A pipe 4 for supplying air to the orifice 5; a pressure sensor 3 connected to the pipe 4; a two-port solenoid valve 2 connected to the pipe 4 for controlling supply / stop of air; and the pressure sensors 3 and 2 A control device 6 is connected to each of the port solenoid valves 2 to control valve opening / closing and input / output data, and a pressure control device 1 connected to the pipe 4 for setting the pressure of the supplied air. .

  Whether the workpiece 8 is seated on the table 9 or at the time of machining is determined based on the back pressure of the air supplied from the pipe 4 and discharged from the detection orifice 5.

  Each of the above devices will be described. The pressure sensor 3 measures the pressure of the gas with a pressure sensitive element such as a semiconductor strain gauge via a diaphragm or the like, converts an analog signal into an electric signal of a digital signal (A / D), and sends it to the control device 6. Output.

  The control device 6 incorporates programs such as a basic main program and a sub determination routine required for seating determination in a central processing unit (CPU) of a computer. As shown in FIG. The solenoid valve 2 and the pressure sensor 3 are electrically connected, and further, the display unit 6a is connected to display a seating determination result, and in the case of the seating state NG, warning means such as flashing characters and a warning sound are provided. Display / warning. A determination result is transmitted from the control device 6 to the outside as an output signal. As a specific configuration example in which the 2-port solenoid valve 2, the pressure sensor 3, the control device 6 and the like are integrally configured, a supply air control unit A is shown in FIG.

  In the workpiece seating determination method, as shown in FIG. 4, the workpiece 8 and the detection surface of the table 9 are preliminarily set in order to set a threshold value as a reference for seating determination and an inclination angle (degree) of back pressure drop. A relationship between the seating distance (gap) and the back pressure with respect to the seating distance (gap) is obtained by calibration.

  The seating determination method according to the present invention will be described using the seating determination device 7 according to the present invention. First, as shown in FIG. 3, whether or not the workpiece 8 is seated is determined by supplying power to the workpiece seating determination device 7 and turning on the two-port solenoid valve 2 by the control device 6. . Thereby, air is discharged from the detection orifice 5. The back pressure at that time is P0 (34 kPa: no workpiece 8).

  Next, the start signal of the external trigger is turned ON. Next, when the workpiece 8 is seated on the table 9, the back pressure measured by the pressure sensor 3 increases from P0 to SV2 (gap detection limit back pressure: 153 kPa, gap is 100 μm).

  Therefore, when the back pressure becomes SV2 based on the data from the pressure sensor 3, the control device 6 issues a closing signal for the 2-port solenoid valve 2 from the program, and the supply of air is stopped. This blocking time is, for example, about 200 to 500 msec.

  Since the two-port solenoid valve 2 is “closed”, the back pressure decreases. In this case, as in the conventional example (Patent Document 1), as shown in FIG. 5, the amount of change in pressure is divided by time to determine the degree of inclination (angle θ) of the back pressure drop. The degree of inclination is compared with a pass / fail judgment line (inclination angle when the gap is 50 μm) in a judgment routine in the CPU of the control device 6.

  In the determination routine, if the inclination is gentler than the pass / fail determination line, the seating is “OK” and it is determined that the workpiece 8 is seated on the table 9. If the slope is tighter than the acceptance / rejection determination line, it is determined that the work 8 is not seated on the table 9 and the result is “NG”. In this case, the alarm means issues a display / alarm or the like from the display unit 6a according to a command from the control device 6. Thereby, there is no need to wait until the back pressure sufficiently rises, and the determination can be made in a short time when the back pressure rises to SV2, and the determination can be made quickly.

  As shown in FIG. 3, when the back pressure falls from SV2 (gap detection limit back pressure: 153 kPa, gap is 100 μm) to SV3 (100 kPa) in t time, an output signal (ON) of determination OK At the same time, in response to a command from the control device 6, the 2-port solenoid valve 2 is opened, and air is supplied to the detection orifice 5.

  Since the workpiece 8 is seated, the back pressure increases. Then, by the continuous measurement of the pressure sensor 3, whether or not seating is performed during processing is controlled by the control device 6 so that the 2-port solenoid valve 2 is supplied with supply air, and the set back pressure is set during processing of the workpiece. Is a threshold value (for example, Pb2: 176 kPa, the gap is 50 μm), and the control device 6 compares the back pressure of this threshold value with the measured back pressure to determine pass / fail.

  If it is less than the threshold value, the seating is “NG” and an output signal (OFF) of the determination NG is output, and at the same time, an alarm is issued from the control device 6 via the display unit 6a. If the back pressure exceeds the threshold (for example, pb1: 193 kPa, gap 20 μm), the seating is “OK” and the processing is continued. In this way, if the clearance, which is the seating distance, is 0 to 50 μm, the processing is continued with the seating OK, and if the clearance exceeds 50 μm, the processing is stopped as NG.

  Further, when machining is completed and the workpiece 8 is detached from the table 9, when the back pressure becomes SV3, the control device 6 becomes seated "NG" in the determination routine, and the output signal (OFF) of the determination NG is Is output.

  Thus, in the first embodiment, whether or not the seat is seated is determined by whether or not the control device stops the supply air using the electromagnetic valve and measures the change in the back pressure to determine whether or not the seat is seated. The control device controls the electromagnetic valve to supply the supply air, uses the set back pressure at the time of machining the workpiece as a threshold value, and determines pass / fail while measuring the back pressure with the pressure sensor 3.

  Next, in Example 2, the seating determination apparatus 7 is configured in the same manner as described above. Although the CPU program in the control device 6 is different, other devices are the same, and a description of the same device is omitted.

  As shown in FIG. 3, when the seat 8 is seated on the table 9, the control device 6 stops the supply air by the 2-port solenoid valve 2 to change the back pressure (inclination). ) Is measured and compared with a change in the back pressure set in advance by the control device 6, a pass / fail decision is made. The same as in the first embodiment.

  Then, whether or not seating is performed during processing is controlled by the control device 6 so that the 2-port solenoid valve 2 is in an “open” state so as to supply supply air. Thereafter, the change in the back pressure drop during workpiece machining (θ: degree of inclination) is continuously measured by the pressure sensor 3 connected to the control device 6. The controller 6 compares the change in the back pressure drop (θ: the degree of inclination) with the change in the back pressure drop (θ: the degree of inclination) that is determined to be a preset workpiece separation gap, and the pass / fail judgment is made. .

  The inclination (θ: degree of inclination) of the back pressure drop is obtained by obtaining a difference ΔP between a back pressure after a predetermined time and a back pressure after a predetermined time in a determination routine incorporated in the CPU of the control device 6. By dividing by the elapsed time (T), the inclination (ΔP / T) is measured, and this is continuously performed in a short time. If the measured inclination is larger than the set reference inclination (the angle θ is large), the output signal is turned off as a determination NG and an alarm is issued to the display unit 6a.

  In the case of the second embodiment, even when the workpiece 8 is seated on the table 9 and the gap is in the range of 0 to 50, for example, a certain back pressure (gap is not generated during machining of the workpiece 8). If the back pressure falls below the set reference from the back pressure, the seating determination is NG. Therefore, if the gap is slightly increased from the current gap, the seating determination NG can be made.

  According to the seating determination method and the apparatus according to the present invention, not only when the workpiece is seated but also the seating state of the workpiece at the time of machining can be determined, which can be widely applied to various machine tools and the like. It is something that can be done.

1 pressure regulator,
2 2-port solenoid valve,
3 Pressure sensor,
4 Piping,
5 Detection orifice,
6 control device, 6a display unit,
7 Seating determination device,
8 Workpiece (object to be detected)
9 tables,
A Supply air control unit.

Claims (4)

A seating determination method for performing pass / fail judgment of a seating state of a workpiece by back pressure of air supplied at each time of sitting on a table of a workpiece and processing,
When the workpiece is seated on the table, whether the seating is successful or not is determined by measuring the change in the back pressure by stopping the supply air by the solenoid valve by the control device, and setting the back pressure preset by the control device. Pass / fail judgment compared to
The success or failure of the seating at the time of machining is controlled by the control device so that supply air is supplied to the solenoid valve, and the back pressure set at the time of workpiece machining is set as a threshold value. Comparing with the control device,
A method for determining seating of a workpiece characterized by the above. A seating determination method for performing pass / fail judgment of a seating state of a workpiece by back pressure of air supplied at each time of sitting on a table of a workpiece and processing,
When the workpiece is seated on the table, whether the seating is successful or not is determined by measuring the change in the back pressure by stopping the supply air by the solenoid valve by the control device, and setting the back pressure preset by the control device. Pass / fail judgment compared to
The success or failure of seating at the time of machining is controlled by the control device so that supply air is supplied to the solenoid valve, and a change in back pressure drop at the time of workpiece machining is continuously measured by a pressure sensor connected to the control device. Then, by comparing the change in the back pressure and the change in the back pressure drop determined to be a preset work separation gap with the control device, pass / fail judgment is performed,
A method for determining seating of a workpiece characterized by the above. A detection orifice of a table that discharges supply air to the workpiece, a pipe that supplies air to the detection orifice, a pressure sensor connected to the pipe, and a two-port electromagnetic that is connected to the pipe and controls supply / stop of air A valve, a control device connected to each of the pressure sensor and the two-port solenoid valve to control valve opening / closing and input / output data, and a pressure adjusting device for air pressure setting connected to the pipe, A seating determination device for performing pass / fail judgment of the seating state of the workpiece by back pressure of air supplied at the time of sitting on the table of the workpiece and at the time of processing,
When the workpiece is seated on the table, whether the seating is successful or not is determined by measuring the change in the back pressure by stopping the supply air by the solenoid valve by the control device, and setting the back pressure preset by the control device. Pass / fail judgment is made in comparison with the change of the above, and whether the seating at the time of machining is determined by controlling the electromagnetic valve to supply the supply air by the control device, the back pressure set at the time of workpiece machining as a threshold, Comparing the threshold back pressure and the back pressure measured by the pressure sensor with the control device,
A workpiece seating determination device characterized by A detection orifice for discharging supply air to the workpiece, a pipe for supplying air to the detection orifice, a pressure sensor connected to the pipe, and a two-port solenoid valve connected to the pipe for controlling supply / stop of air A control device connected to each of the pressure sensor and the 2-port solenoid valve for controlling valve opening / closing and inputting / outputting data, and a pressure adjusting device for setting air pressure connected to the pipe. A seating determination device for performing pass / fail determination of the seating state of the workpiece by back pressure of air supplied at the time of sitting on the table and at the time of processing,
When the workpiece is seated on the table, whether the seating is successful or not is determined by measuring the change in the back pressure by stopping the supply air by the solenoid valve by the control device, and setting the back pressure preset by the control device. Pass / fail judgment is made in comparison with the change of the above, and whether the seating at the time of machining is determined by controlling the electromagnetic valve to supply the supply air by the control device, the back pressure set at the time of workpiece machining as a threshold, Comparing the threshold back pressure and the back pressure measured by the pressure sensor with the control device,
A workpiece seating determination device characterized by

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