JP2004181494A - Device and method for laser beam machining - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To conduct drilling and patterning at high speed and with high accuracy without stopping a machining table, by using a pulse output laser, using no dedicated scale, and using a device of simple composition. <P>SOLUTION: A trigger signal for oscillating laser pulses from a laser beam device 20 is generated by applying the output of a linear scale 30, which is used for the feedback control of the position of the machining table 14. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser processing method and apparatus for processing a processing object placed on a processing table driven by a motor using a laser pulse oscillated by a trigger signal, and in particular, CO ₂ , excimer. Laser processing method and apparatus capable of performing high-precision processing at high speed suitable for use in processing with one pulse at each position by a pulse laser of solid-state laser such as YAG or the like About.
[0002]
[Prior art]
In conventional machining using a pulse output laser, the machining table is normally positioned by a command from the control device, and a trigger pulse is sent to the laser device at the timing when the machining table stops moving, thereby oscillating the laser pulse. .
[0003]
[Problems to be solved by the invention]
For this reason, it takes several hundred milliseconds for deceleration, stop, and acceleration for one processing, and this requires laser irradiation time. In addition, a delay due to a command from the control device (software-several milliseconds, hardware-several microseconds) is added, and in the case of one-pulse machining, gas laser irradiation is completed in several nanoseconds to several tens of nanoseconds. These accounted for most of the time. Thus, even if the laser processing itself is high speed, the overall processing speed is slow due to the factors of the table drive system.
[0004]
In order to solve such a problem, Patent Document 1 discloses that a Q-switch oscillation is performed at a desired repetition frequency at a desired position during traveling of the XY table by output of a linear encoder for detecting the position of the XY table. Is described.
[0005]
[Patent Document 1]
JP-A-2001-71160 [0006]
Patent Document 2 describes that a trigger for laser irradiation is generated by using a dedicated linear scale that generates a pulse signal for each predetermined movement position of a workpiece.
[0007]
[Patent Document 2]
Japanese Patent Laid-Open No. 2000-210784
However, in Patent Document 1, Q-switch oscillation is performed, and in Patent Document 2, the linear scale is not incorporated in the XY table drive system, and there is a problem that the configuration becomes complicated.
[0009]
The present invention has been made to solve the above-mentioned conventional problems, and is capable of performing processing with a pulse output laser with high accuracy and high speed with a simple configuration without using a dedicated scale. Let it be an issue.
[0010]
[Means for Solving the Problems]
The present invention feedback-controls the position of the processing table in a laser processing method in which a processing object arranged on a processing table driven by a motor is processed using a laser pulse oscillated by a trigger signal. Therefore, the above-mentioned problem is solved by generating the trigger signal using the output of the encoder.
[0011]
Further, the accuracy of the processing table is further improved by correcting the displacement of the processing table.
[0012]
The present invention also provides a feedback of the position of the machining table in a laser machining apparatus that uses a laser pulse oscillated by a trigger signal to machine a workpiece to be placed on a machining table driven by a motor. The problem is similarly solved by providing an encoder for controlling and a means for generating the trigger signal using the output of the encoder.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0014]
In the present embodiment, as shown in FIG. 1, a processing object placed on a processing table (for example, an XY table) 14 driven by a servo motor 10 via a ball screw 12 is used as a trigger signal (for example, a trigger pulse). ), The output of the linear scale 30 for feedback control of the position of the processing table 14 is input to the trigger generation board 32. Thus, a trigger pulse for the laser device 20 is generated.
[0015]
In the figure, 40 is a position command device included in a control device such as an NC machine, for example, and 42 controls the servo motor 10 in accordance with the output of the linear scale 30 input via the trigger generation board 32. This is a servo amplifier.
[0016]
The machining table 14 is fully closed and controlled with high accuracy by a position pulse of the linear scale 30 via a servo amplifier 42.
[0017]
As the laser device 20, for example, a gas pulse laser such as CO ₂ or excimer or a solid pulse laser such as YAG is used.
[0018]
The ball screw 12 has a high accuracy, and the resolution of the linear scale 30 is, for example, 0.1 μm or more.
[0019]
The trigger generation board 32 includes amplifiers 34 and 36 and a trigger generation circuit 38.
[0020]
In the present invention, as shown in detail in FIG. 2, the position pulse of the linear scale 30 output is counted by the counter 38A, and based on the pitch (interval) table stored in the memory 38B in advance, for comparison (pitch). The data 38C is set in the comparator 38D at any time and at high speed, compared with the comparator 38D, and when the values are equal, a trigger pulse is output.
[0021]
The pitch data is set each time, but error data unique to the table is stored in advance as pitch error data. At this time, the count is an absolute value, and pitch data in consideration of the error amount at that position is created in advance for the designated pitch.
[0022]
At the time of processing, the counter 38A counts together with the table operation, and outputs a trigger pulse when it is the same as the set pitch position as shown in FIG. The next data is set simultaneously with the trigger output.
[0023]
The operation will be described below.
[0024]
The position command output from the position command device 40 is sent to the servo amplifier 42, and the servo amplifier 42 drives the servo motor 10. As the servo motor 10 rotates, the ball screw 12 also rotates and the machining table 14 moves. As the machining table 14 moves, the linear scale 30 outputs a position signal (pulse output). The output position signal is taken into a dedicated trigger generation board 32. Here, the position signal is branched, and one of them returns to the servo amplifier 42 via the amplifier 34 to form a normal full-closed servo loop.
[0025]
The other position signal is counted by a dedicated counter 38A in the trigger generation circuit 38 via the amplifier 36. Here, the pulse and position are converted, and a trigger pulse is output to the laser device 20 with a preset number of pulses (= position). The laser device 20 is oscillated by the trigger pulse, and the workpiece on the processing table 14 is irradiated with the laser pulse 22 for processing. At this time, the table continues to move without stopping.
[0026]
Note that the output of the laser device 20 is output in about 3 μs from the detection of the position pulse of the processing table 14 even if the delay of the electrical circuit is taken into consideration. Therefore, when the table speed is driven at 10 m / min, the target point can be processed with a deviation amount of about 0.5 μm.
[0027]
This accuracy is greatly influenced by the table accuracy. A processing table often used in normal laser processing is about ± 10 μm. This value means the maximum error width with respect to the full width of the table stroke.
[0028]
Normally, when the table axis error is measured from the origin, it can be measured as the amount of deviation from the command position with a laser-side length gauge or the like as shown in FIG. This error depends on the mechanical manufacturing accuracy and is not always the same. And there is a big influence compared with the fluctuation on the control system side. In order to correct these, in the present embodiment, the error amount is used as it is as a correction amount and is taken into account when counting pulses. As a result, the axis-specific error amount is canceled, and highly accurate machining is possible.
[0029]
In the present embodiment, since the table axis error is corrected in this way, highly accurate position control is possible.
[0030]
In the above description, the X axis of the XY table has been described, but the same applies to the Y axis. The application target of the present invention is not limited to an XY table, and can be applied to a table having one axis or three axes or more, for example. In the embodiment, the linear scale is used as the encoder. However, the type of the encoder is not limited to this, and may be a rotary encoder, for example.
[0031]
【The invention's effect】
According to the present invention, it is possible to perform drilling and patterning at high speed and with high accuracy using a pulse output laser without using a dedicated scale, with a simple configuration, and without stopping the processing table. Become.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing an overall configuration of an embodiment of the present invention. FIG. 2 is a block diagram showing a configuration of a trigger generation board according to the embodiment. FIG. 3 is a count pulse and setting data for explaining the operation. Time chart showing examples of trigger pulse relationships [Fig. 4] Diagram showing examples of table axis errors [Explanation of symbols]
10 ... Servo motor 12 ... Ball screw 14 ... Machining table (XY table)
20 ... Laser device 22 ... Laser pulse 30 ... Linear scale 32 ... Trigger generation board 40 ... Position command device 42 ... Servo amplifier

Claims (3)

In a laser processing method in which a processing object arranged on a processing table driven by a motor is processed using a laser pulse oscillated by a trigger signal,
A laser processing method, wherein the trigger signal is generated by using an output of an encoder for feedback control of the position of the processing table. The laser processing method according to claim 1, wherein a position shift of the processing table is corrected. In a laser processing apparatus configured to process a processing object placed on a processing table driven by a motor using a laser pulse oscillated by a trigger signal,
An encoder for feedback control of the position of the processing table;
Means for generating the trigger signal using the output of the encoder;
A laser processing apparatus comprising:

Images