JP2597598B2 - Nozzle check device in laser beam machine - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a nozzle check device in a laser processing machine, and particularly to a device provided with a gap sensor integrated with a nozzle, in which the sensor function is to be checked. It is.

(Prior art and its problems) Conventionally, in laser processing, the distance between the laser nozzle and the work, that is, the focus of the laser beam is always kept at a constant height with respect to the work in order to obtain the optimum processing state. A so-called gap control, in which a constant gap amount is always maintained constant, is performed.

As a gap sensor for this purpose, there is a gap sensor provided with a contact type or non-contact type distance sensor at a position near the side of the laser nozzle. However, since the gap is detected at a position slightly deviated from the processing position, an appropriate gap amount cannot be measured at the processing position, and as a result, a good processing state cannot be obtained.

For this reason, an electromagnetic gap sensor such as a capacitance type,
Generally, a nozzle integrated with a nozzle or welded to the tip of the nozzle to detect a gap amount at a processing position in a non-contact manner is used.

However, when spatter S or high reflection heat which jumps violently from the work surface due to the laser irradiation is applied, the nozzle tip, that is, the sensor portion is melted by heat, or the deterioration of the sensor function cannot be avoided due to abrasion or thermal deformation.

As a result, the sensor output characteristic with respect to the gap amount is different from the actual sensor output characteristic (for example, line A in FIG. 5), and is different from the actual gap amount. ).

In such a case, proper gap control cannot be performed, and the processing state deteriorates. Therefore, it is necessary to replace the nozzle with a nozzle having proper initial sensor output characteristics.

However, conventionally, such deterioration of the sensor function is caused by
In many cases, it is known after looking at the processing state of the actually processed work, and the operator must always observe the processing state. In addition, the poor processing condition of the work is not necessarily due to the deterioration of the sensor function of the nozzle, and even a nozzle that has a proper function that has not deteriorated is removed and replaced with a new nozzle In some cases, wasteful measures such as doing so may be taken, which has been a cause of lowering work efficiency.

In addition, if processing is continued with the same nozzle while considering the deterioration of the nozzle, the correct gap amount cannot be measured due to changes in the sensor output characteristics, and as a result, proper gap control cannot be performed and processing defects will continue. There was also a risk that

For this reason, by properly checking the sensor output of the nozzle and accurately knowing the deterioration of the nozzle, it is possible to take appropriate measures such as immediately replacing the nozzle, maintain appropriate gap control, and solve the above problems. It is assumed that.

(Means for Solving the Problems) Accordingly, the present invention provides a non-contact type gap sensor integrated with a nozzle, in which the nozzle is positioned at a predetermined check reference position, and the sensor output of the nozzle at that position is determined. Is provided, and means for determining the quality of the measured value are provided, and by providing means for displaying the determination result, for example, the nozzle is automatically positioned at the check reference position simply by pressing a check command switch, The sensor output at the position is measured, and depending on whether the sensor output is within a range of a preset reference output,
Since the quality of the nozzle is determined and displayed, the operator can easily and accurately know whether or not the sensor function of the nozzle has deteriorated by appropriately performing a nozzle check, and immediately perform nozzle replacement or the like. By taking measures, proper gap control is maintained with correct gap amount measurement.

That is, the present invention includes a gap sensor at the tip of the nozzle that detects the gap between the nozzle tip and the work in a non-contact manner, and performs a constant gap amount control based on the gap amount detected by the gap sensor. In a laser beam machine that performs processing, a nozzle check command unit, a nozzle positioning unit that positions a nozzle at a predetermined check reference position in a gap amount constant control OFF state by the nozzle check command, a reference output range with respect to the check reference position A reference output setting means for setting the sensor output of the gap sensor at the check reference position, and if the value is within the reference output range, the result is OK. Determination means, and display means for displaying a determination result by the nozzle quality determination means It consists of.

(Example) Next, a specific example of the present invention will be described with reference to the drawings.

The present embodiment relates to a laser processing machine used for, for example, flat plate processing, in which a laser processing head is moved in a Y-axis direction and a Z-axis direction with respect to a workpiece fed and moved in an X-axis direction.

The nozzle 1 is mounted on the laser processing head (not shown), and the optical axis is aligned with the Z axis. And nozzle 1 itself forms a capacitance sensor as the gap sensor, by detecting the electrostatic capacitance C _L between the nozzle tip and the workpiece W, for measuring the amount of gap therebetween in a non-contact It is as follows.

In addition, this laser processing machine has a sensor output sampling function as shown in the flow of FIG. 1, a gap control function for constant gap amount control as shown in the flow of FIG. 2, and a nozzle as shown in the flow of FIG. It has a check function.

When the nozzle is first installed, or when you notice processing defects, or at any time, issue a sampling command,
In the gap amount constant control OFF state, as shown in the sampling control flow of FIG. 1, the nozzle 1 is moved from a predetermined sampling reference position corresponding to the reference block (for example, when the gap amount between the nozzle tip and the reference block is 0).
Is moved upward in the optical axis direction by a specified amount, for example, 0.1 mm. That is, these height positions are positions where the gap amount is actually changed to 0.1 mm, 0.2 mm, 0.3 mm,....

Each time the gap is moved, the sensor output from the nozzle 1 is sampled and written to a sampling data storage circuit 4 described later. If this sampling data is graphed, a characteristic curve such as the line A in FIG. 5 is obtained.

At the time of the gap control with the gap amount constant control ON, as shown in the gap control control flow of FIG. 2, the corresponding gap stored in the sampling data storage circuit 4 is based on the sensor output of the sensor of the nozzle 1. The gap amount is read, the gap amount is compared with a preset gap amount as a control reference value, and the deviation amount is sent as a gap control signal, and the gap amount between the tip of the nozzle 1 and the work W is determined. Nozzle 1 so that it matches the above set gap amount.
Is controlled in the optical axis direction.

That is, in FIG. 4, the sensor output from the nozzle 1 is converted into a DC voltage by the sensor circuit 2 and sent to the data processing circuit 3. The data processing circuit 3 is provided with a sampling data storage circuit 4, a gap amount display circuit 5, a data comparison circuit 6, a Z-axis drive pulse generation circuit 7, and an output check circuit 8 as a nozzle quality judgment unit.

In the sampling data storage circuit 4, for example, 0.1 m
.., 0.2 mm, 0.3 mm..., and gap amount data for each 0.1 mm are registered in advance, and the sensor output voltage from the sensor circuit 2 is stored in a sensor output storage unit (not shown) corresponding to each gap amount. Is stored in correspondence with each gap amount data, and is rewritten successively with new sampling data at each sampling.

After the completion of the sampling, the gap amount data output from the sampling data storage circuit 4 based on the sensor output from the nozzle is sent to the data comparison circuit 6 and set in advance by the gap amount setting means 9 provided in the operation unit. This is compared with the set gap amount. The deviation between the two is sent to the Z-axis drive pulse generation circuit 7 as a gap control signal, and is sent to the Z-axis motor drive control circuit 12 via an interrupt circuit 11 in the NC device 10 to perform Z-axis control. The nozzle 1 is controlled to move in the optical axis direction.

Further, the gap amount data output from the sampling data storage circuit 4 is numerically displayed on the gap amount display 13 via the gap amount display circuit 5 as it is.

The NC apparatus 10 incorporates a normal processing program 14 for processing and feeding the nozzle 1 and a slide table (not shown) in the X, Y, and Z-axis directions, and a nozzle check program 15 serving as a nozzle positioning means. It is selectively executed by the command 16 and a check command from the nozzle check command means 17.

The Z-axis feed control signal from the machining program 14 is sent to the Z-axis motor drive control circuit 12 via the interrupt circuit 11,
The drive control of the Z-axis motor 18 controls the feed of the nozzle 1 in the optical axis direction.

Nozzle check program 15 controls gap amount constant
In the OFF state, as shown in the nozzle check control flow of FIG. 3, first, the nozzle 1 is automatically positioned at a predetermined check reference position corresponding to, for example, a reference block. The check reference position is set, for example, at a position where the gap amount between the nozzle tip and the reference block is 4.0 mm in the Z-axis direction. The sensor output from the nozzle 1 at this position is sent to the output check circuit 8, and it is determined whether or not the output is within a reference output range set in advance by reference output setting means 19 provided in the operation unit. .

As shown by the hatched range in FIG. 5, the reference output is set to a range of, for example, 6.2 V to 7.4 V with a check reference gap of 4.0 mm. The nozzle OK / NG display means 20 displays “OK” at points a and b, and “NG” at point c in FIG.

In the case of "OK", the gap control can be continued with the sampling data as it is, and in the case of "NG", a warning lamp or an alarm is given to the operator without fail, and the nozzle 1 is replaced or sampling is performed. Encourage data rewriting.

Sampling data rewriting
By operating 21, a driving pulse for raising the Z-axis by 0.1 mm is generated from a Z-axis driving pulse generating circuit 7 serving as a sampling driving means, and the gap between the nozzle tip and the reference block is reduced from 0 to 0.1 mm. The nozzle 1 detects the capacitance at each position, the sensor output is sent to the sampling data storage circuit 4 via the sensor circuit 2, and the sampling of the sensor output voltage corresponding to each gap amount data is performed. Data is rewritten from old data to new data.

In this way, the current sensor output characteristics of the nozzle 1 are sampled, and during processing, gap amount data corresponding to the actual gap amount is obtained from the sampled data based on the sensor output, and sent to the data comparison circuit 6. The gap control is performed so that the gap amount between the nozzle tip and the work W always coincides with the set gap amount and becomes constant.

Incidentally, it is also possible to easily incorporate a command program such that a check command is automatically issued from the nozzle check command means 17 after the machining program 14 has been executed several times in the NC device 10, and in this case, Since the nozzle check is always performed in the set cycle, for example, even though the operator has degraded the sensor output characteristics, the worker may make a statement that the nozzle check will be performed, causing unexpected machining failure. Can be prevented beforehand.

Furthermore, it is also possible to easily incorporate a sampling program executed by a sampling command into the NC device 10 and connect it to the interrupt circuit 11 similarly to the nozzle check program 15. The nozzle 1 is automatically sent to the sampling reference position by the NC device 10, and the Z-axis can be immediately fed and driven by a predetermined amount to perform sampling, thereby improving workability. Also, in this case,
It is also possible to take in the NG output signal from the nozzle check and automatically execute the sampling program when NG is detected.

Further, the gap sensor is not limited to the capacitance type sensor, and may use another non-contact sensor such as a magnetic sensor.

In addition, the laser processing head has two additional
In a 5-axis laser beam machine that can control the direction of the optical axis at the irradiation end by providing a rotating main shaft, a gap control motor separate from the Z-axis motor is provided, and only the nozzle part can be moved in the optical axis direction. And a Z-axis drive pulse generation circuit 7
By sending the data to the drive control unit of the control motor instead of sending the data to the control motor, the feed control can be easily performed by adding the gap control at the tip of the nozzle in addition to the processing feed by the processing program. In the sampling driving of the nozzle, the control motor may be driven and controlled to move the nozzle by a predetermined amount in the optical axis direction.

In addition, the nozzle structure may be one in which the nozzle itself is configured as a gap sensor, one in which an electrode as a gap sensor is welded to the tip of the nozzle, or the first for gap detection.
The electrode and the second electrode provided to cover the side surface of the first electrode to eliminate the influence of the sensor output from the nozzle side by the three-dimensional work may be provided, and any other non-contact type sensor structure may be used. The present invention can be applied.

(Effect of the Invention) As described above, according to the present invention, for example, in a device provided with a non-contact type gap sensor integrated with a nozzle,
Since the nozzle is positioned at a predetermined check reference position, the sensor output of the nozzle at that position is measured, and means for determining the quality of the measured value are provided, and means for displaying the determination result are provided. By simply pressing the command switch, the nozzle is automatically positioned at the check reference position, the sensor output at that position is measured, and the nozzle is determined based on whether the sensor output is within a preset reference output range. Is judged and displayed. Thereby, the operator can easily and accurately know whether or not the sensor function of the nozzle has deteriorated by performing the nozzle check at predetermined time intervals or as appropriate.
By immediately performing processing such as nozzle replacement, it is possible to continue appropriate gap amount constant control by correct gap amount measurement.

In addition, a nozzle check command is issued by, for example, an NC device.
By automatically outputting the output every predetermined cycle, the sensor function of the nozzle can be reliably checked without the operator's operation. There is no need to put it out, and you can work with peace of mind.

[Brief description of the drawings]

FIG. 1 is a sampling control flow chart in the laser beam machine according to the present invention, FIG. 2 is a gap control control flow chart of the above, FIG. 3 is a nozzle check control flow chart of the same, and FIG. 4 is a specific control circuit of the present invention. FIG. 5 is a diagram showing a change in sensor output characteristics and a reference output range. 1 ... nozzle integrated with gap sensor; 8 ... output check circuit as nozzle quality judgment means; 15 ... nozzle check program as nozzle positioning means; 17
…… Nozzle check command means, 19 …… Reference output setting means, 20 …… Nozzle pass / fail indication means, W …… Work.

Claims (1)

(57) [Claims] A gap sensor for detecting a gap amount between a nozzle tip and a work in a non-contact manner at a nozzle tip, and performing constant gap amount control based on the gap amount detected by the gap sensor. In a laser beam machine for processing, a nozzle check command means, a nozzle check command, a nozzle positioning means for positioning a nozzle at a predetermined check reference position in a gap amount constant control OFF state, and a reference output range with respect to the check reference position. A reference output setting means to be set, and a sensor output of the gap sensor at the check reference position is measured. If the value is within the reference output range, OK is determined, and if the value is outside the reference output range, NG is determined. Means, and a display means for displaying a result of the determination by the nozzle quality determination means. A nozzle check device in a laser beam machine.