JPH0146237B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a laser processing apparatus,
The present invention relates to a distance detection device used when machining is performed while maintaining a constant distance between a workpiece and a machining head.

Conventionally, a contact type distance detection device has been used as this type of distance detection device. As shown in FIG. 12, a pair of hook-shaped contact tools 2 and 3 are provided at the lower end of the sensor body 1, and near the lower end curved portions 2a and 3a of both contact tools 2 and 3 in the front and back direction (see FIG. A structure is known in which a pair of connectors 4 and 5 for connecting both the contact members 2 and 3 are fixed to the right and left vicinity in FIG. 11).

In the conventional distance detection device configured as described above, the laser beam L is condensed by the condenser lens 6 and focused on the laser processing point P on the surface of the workpiece 7 to process the workpiece 7. At this time, there are four contact points between the workpiece 7 and the contactor: the lower end curved portions 2a, 3a of each of the contact tools 2, 3, and the middle curved portions 4a, 5a of each of the connectors 4, 5. If even one of them is in contact with the workpiece 7, the contact will not fall into the hole even if the other contacts are not in contact with the workpiece 7 (even if they are above the machined hole), and the distance will be reduced. can be detected.

However, in the case of such a contact-type distance detection device, each of the above-mentioned curved portions 2 is formed on the surface of the workpiece 7.
Since a, 3a, 4a, and 5a are in contact with each other, there is a problem in that contact marks remain on the surface of the workpiece 7.

The present invention was made in view of the above circumstances, and
The purpose is to provide a distance detection device for a processing device that can perform high-precision copy processing without damaging the surface of the workpiece (processed material) and even if the workpiece has a hole, etc. that has already been machined. It is in.

In order to achieve the above object, the present invention includes a plurality of non-contact distance detectors installed in a processing head, and enables only the output within a predetermined range of the detection values detected by each of the distance detectors to be effective. a signal processing circuit to
a movement control circuit that averages the outputs of the signal processing circuits and controls a movement mechanism for moving the processing head based on the average value; Only the validated detection values are averaged, and based on this average value, the movement control circuit operates the movement mechanism to control the distance between the processing head and the workpiece.

Hereinafter, one implementation of the present invention will be described based on FIGS. 1 to 9.

In the figure, reference numeral 10 denotes a processing head of a processing device such as a laser cutting machine, and a condensing lens 11 for condensing a laser beam generated by a laser oscillator (not shown) is installed at the tip thereof. Further, a motor 12 is connected to the machining head 10 via a transmission mechanism 13 such as a ball screw, rack, or pinion, and the machining head 10 is moved in the vertical direction (Z-axis direction) by this motor 12. I'm starting to do that. Further, around the processing head 10, as shown in FIG. are arranged at an angle of approximately 120°, and these first, second, and third distance detectors 14, 15, and 16 direct the light to the XY table T.
By applying the light to the surface of the workpiece 17 above and receiving the reflected light, as shown in _FIG . each distance detector 14,1
The adjustment circuit 2 of each signal processing circuit 18, 19, 20 detects the amount of deviation d when the parts 5 and 16 are deviated with respect to the workpiece 17, and adjusts the output voltage proportional to the amount of deviation d.
1, 22, and 23. These first, second and third adjustment circuits 21, 2
2 and 23 are amplifiers 21a, 22a, 2, respectively.
3a and two limiter circuits 21b, 21
c, 22b, 22c, 23b, 23c and transistors 21d, 21e, 22d, 22e, 23
d, 23e, resistors 21f, 21g, 22f, 22
g, 23f, and 23g. The first, second and third adjustment circuits 21, 22,
23 amplifies the output voltages of the distance detectors 14, 15, and 16 using the amplifiers 21a, 22a, and 23a to generate an output signal V ₀₁ proportional to the deviation amount d, as shown in FIG. In addition to outputting V ₀₂ and V ₀₃ respectively, the above output voltages are applied to each limiter circuit 21.
b, 22b, 23b and transistors 21d, 2
2d, 23d, and resistors 21f, 22f, 23f, as shown in _{FIG .}
−d ₃ or more, positive voltages L ₁₁ , L ₁₂ , L ₁₃ are output, and each of the above output voltages is applied to each limiter circuit 21.
c, 22c, 23c and transistors 21e, 2
2e, 23e and resistors 21g, 22g, 23g, the deviation amounts are +d ₁ , +d ₂ , + as shown in FIG.
At d ₃ or less, positive voltages L ₂₁ , L ₂₂ , and L ₂₃ are output.

Output signals of each of the above adjustment circuits 21, 22, 23
V ₀₁ , V ₀₂ , and V ₀₃ are input to the first, second, and third selection circuits 24 , 25 , 26 , respectively, and the limiter outputs L ₁₁ ,
L ₂₁ , L ₁₂ , L ₂₂ , L ₁₃ , and L ₂₃ are input to each selection circuit 24, 25, and 26 via each AND circuit AND1, AND2, and AND3, respectively. and,
These first, second and third selection circuits 24, 25,
26 is the output of each AND circuit AND1, AND2, AND3, as shown in FIGS. 7 to 9.
When S ₁ , S ₂ , and S ₃ are at high level (positive voltage), that is, the amount of deviation d is between -d ₁ and +d ₁ , between -d ₂ and +d ₂ , and between -d ₃ and +d, respectively. ₃ , the output signals of the respective adjustment circuits 21, 22, 23 V ₀₁ , V ₀₂ ,
V ₀₃ is output to the adder 27, and the outputs S ₁ , S ₂ ,
When _S3 is at a low level, each of the three input terminals of the adder 27 is set to 0 volts (grounded).

The adder 27 is composed of resistors R ₁ , R ₂ , R ₃ and an operational amplifier OP, and each selection circuit 24,
The outputs V ₀₁ ′, V ₀₂ ′, and V ₀₃ ′ of 25 and 26 are added together. This adder 27 is connected to an average value circuit 28 of the movement control circuit X, and this average value circuit 28 is connected to each of the AND circuits described above.
Based on the outputs S ₁ , S 2 , S ₃ of AND1, _AND2 , AND3, the first, second, and third distance detectors 14, 1
The effective detectors among the 5 and 16 detectors are determined, and the output of the adder 27 is divided by the number of effective detectors to calculate the average value. Also,
The output (average value) of the average value circuit 28 is sent to the comparison circuit 29.
The comparator circuit 29 outputs to the motor drive device 30 a command signal proportional to the difference between the reference voltage V _R input in advance and the average value. The motor drive device 30 drives the motor 12 based on the command signal, and these motor drive device 30, motor 12, and transmission mechanism 1
3 constitute a moving mechanism 31 for the processing head 10.

In addition, each of the above AND circuits AND1, AND2,
AND3 is connected to an OR circuit OR, and this OR circuit OR is connected to the alarm device 32 via an inverter circuit INV. This alarm device 32 includes all AND circuits AND1, AND2,
It operates when the outputs S ₁ , S ₂ , and S ₃ of AND3 are "0" (low level) and issues an alarm.

Next, the operation of the distance detection device configured as described above will be explained.

When performing processing such as cutting on the workpiece 17, the workpiece 17 to be processed is placed on the XY table T, and the XY table T is moved horizontally as appropriate.
While the workpiece 17 is moved, a laser beam is emitted by a laser oscillator, and the laser beam is focused by the condensing lens 11, and the workpiece 17 is processed, such as cutting, at the condensing point, as in the conventional case. At this time, work 1
7 and the processing head 10 is determined by each distance detector 1.
The output voltages of these first, second, and third distance detectors 14, 15, and 16 are detected by the first, second, and third signal processing circuits 18, 19, and 16, respectively. 20, it is determined whether it is valid or invalid. That is, each distance detector 14, 15,
16 output voltages of the distance detectors 14, 15, 1
Within the distance detectable range of 6 (centered on the standard detection distance D ₀ , -d ₁ to +d ₁ , -d ₂ to +d ₂ , -d ₃ to +
_d3 ), a voltage proportional to the deviation amount d is output as shown in FIGS. When detection points 15 and 16 are above the cut hole), the output voltage is 0V.
become. Therefore, three distance detectors 14, 15,
16 are all within their distance detectable ranges, a voltage proportional to the deviation amount d detected by each distance detector 14, 15, 16 is input to the adder 27 and added. The added values are averaged by an average value circuit 28. As a result, the first
The voltage obtained by averaging the values detected by the second and third distance detectors 14, 15, and 16 is determined as a reference voltage by the comparator circuit 29.
The machining head 10 is moved up and down via the motor drive device 30, the motor 12 _, and the transmission mechanism 13 based on a command signal proportional to this difference. It is controlled to match the surface of 17. For this reason,
Even if the surface of the workpiece 17 is uneven, the output voltage of each distance detector 14, 15, 16 changes based on the unevenness, and the average value of these output voltages changes. There is a difference between _R and
The moving mechanism 3 is controlled by a command signal proportional to this difference.
1, the machining head 10 is controlled to move up and down, and the position of the converging point of the laser beam and the workpiece 17 is maintained constant and does not shift vertically.

Furthermore, if one or two of the three distance detectors 14, 15, and 16 are once above the hole and are out of their distance detectable range, the distance detectors 14, 15, and 16 The output voltages of the distance detectors 14, 15, 16 outside the possible range are invalidated (0V) by the above-mentioned signal processing circuits 18, 19, 20.
However, the remaining distance detectors 14, 15, 16
Since the output voltage of is input to the comparator circuit 29 via the adder 27 and the average value circuit 28, the workpiece 17 can be machined in the same way as when the three distance detectors 14, 15, and 16 are enabled. The process never stops.

Furthermore, first, second, and third distance detectors 14, 1
5 and 16 are all out of their distance detectable range, for example, when the machining head 10 is placed above a hole large enough to fit inside, each distance detector 14, 15 and 16 are disabled (0V) by each signal processing circuit 18, 19, and 20, and each AND circuit AND
1, AND2, AND3 low level output S ₁ , S ₂ ,
When _S3 is input to the OR circuit OR, the alarm device 32 is activated via the inverter circuit INV,
Perform processing such as issuing an alarm to notify workers or stopping processing equipment.

In this case, the output of the adder 27 is 0V, and therefore the output of the average value circuit 28 is also 0V.
If the reference voltage V _R input to the comparator circuit 29 is set to 0V, the machining head 10 can
When the third distance detectors 14, 15, and 16 are all disabled, the vertical movement is stopped. For this reason,
The processing head 10 does not fit into the hole of the workpiece 17 and come into contact with the workpiece 17. Then, when the XY table T moves and the machining head 10 is removed from the hole position of the workpiece 17, each distance detector 14, 15, 16 becomes effective, so the normal servo copying process described above continues. be done.

As explained above, the present invention includes a plurality of non-contact distance detectors provided in a processing head, and a signal that enables only the output within a predetermined range of the detection values detected by each of the distance detectors. Since it is equipped with a processing circuit and a movement control circuit that averages the outputs of the signal processing circuit and controls a movement mechanism that moves the processing head based on this average value, it is possible to use a plurality of distance detectors. Among the outputs of the machine, only the detection values enabled by the signal processing circuit are averaged, and based on this average value, the movement control circuit operates the movement mechanism to control the distance between the machining head and the workpiece. Therefore, if at least one distance detector is within the distance detectable range, the workpiece can be machined, machining efficiency can be increased, and the reliability of operation of the processing equipment can be maintained at a high level. Since copy processing can be performed based on the average value of the outputs of a plurality of distance detectors, processing accuracy can be greatly improved. In addition, since it uses a non-contact type distance detector, compared to the conventional contact type,
It has excellent effects such as not damaging the workpiece (processed material).

[Brief explanation of drawings]

1 to 9 show an embodiment of the present invention, in which FIG. 1 is a schematic configuration diagram, FIG. 2 is a schematic layout diagram of each distance detector, and FIG. 3 is a schematic configuration of an adjustment circuit section. Figure 4 shows the output signals V ₀₁ , V ₀₂ ,
Characteristic diagram of V ₀₃ , Figure 5 is a characteristic diagram of limiter outputs L ₁₁ , L ₁₂ , L ₁₃ of each adjustment circuit, Figure 6 is a characteristic diagram of limiter outputs L ₂₁ , L ₂₂ , L ₂₃ of each adjustment circuit, Figure 7 is a characteristic diagram of the output V ₀₁ ' of the first selection circuit, Figure 8 is a characteristic diagram of the output V ₀₂ ' of the second selection circuit, and Figure 9 is a characteristic diagram of the output V ₀₃ ' of the third selection circuit. , Figures 10 to 1
Figure 2 shows a conventional distance detection device.
The figure is a side view, FIG. 11 is a sectional view taken along the line XI-XI in FIG. 10, and FIG. 12 is a front view. X...Movement control circuit, 10...Processing head, 1
4...Non-contact distance detector (first distance detector),
15...Non-contact distance detector (second distance detector),
16...Non-contact distance detector (third distance detector),
17... Work, 18... First signal processing circuit, 1
9... Second signal processing circuit, 20... Third signal processing circuit, 31... Movement mechanism.

Claims (1)

[Claims] 1. In a distance detection device in a processing device that operates a movement mechanism for moving a processing head, maintains a constant distance between the processing head and a workpiece, and processes the workpiece, a plurality of distance detection devices provided on the processing head are used. of the non-contact distance detectors, a signal processing circuit that enables only the output within the distance detectable range among the detection values detected by each of the distance detectors, and averaging the outputs of the signal processing circuit, A distance detection device for a processing device, comprising a movement control circuit that controls the movement mechanism based on this average value.