JPH0357574A - Electron beam working machine - Google Patents

Abstract

PURPOSE:To prevent the wall of a working chamber from being melted by providing a deviation detecting circuit for monitoring a variation of a level of a detection waveform of an electron beam detecting device and detecting a fact that an electron beam is deviated from an object to be worked. CONSTITUTION:In the case an electron beam 3 is welding an object 4 to be welded, a large quantity of reflected electrons or secondary electrons are generat ed, therefore, a DC level of a detection waveform of an oscilloscope 13 is high. When an electron beam 3' deviates from an object 4' to be welded, the secon dary electron 9 decreases suddenly being in inverse proportion to the square of a distance, therefore, the DC level of the detection waveform becomes low. By detecting the time 17 of the instant of this deviation by a deviation detecting circuit 15, the generation of the electron beam 3 can be stopped before melting a wall of a welding chamber 16. In such a way, melting of the wall of the working chamber is prevented, and it can also be detected that the electron beam deviates from the object 4' to be worked.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electron beam processing machine, and particularly to an electron beam processing machine that prevents the walls of the processing chamber from being melted when the electron beam leaves the workpiece. It is something.

[Prior Art] FIG. 3 shows a schematic structure of an electron beam welding machine as a conventional electron beam processing machine having a device for detecting a processing line, such as a welding line, as disclosed in, for example, Japanese Patent Laid-Open No. 60-3985. This is a diagram.

In the figure, (1) is a high-voltage power supply whose one end, for example, the ten terminal, is grounded, (2> is an electron gun connected between both ends of this high-voltage power supply (1), and (3) is this electron gun (2>). (4) is the workpiece to be processed by this electron beam (3), in this case the workpiece to be welded, and (5) is the electron gun (
2) and the workpiece (4) to focus the electron beam (3) generated by the electron gun (2> on the surface of the workpiece (4), (6>) Focusing coil (
5) and the object to be welded (4).
) to scan the electron beam (3) across the processing line (4), for example, the welding line (7), (8) is the deflection coil (2).
6) and the object to be welded (4) to capture the reflected electrons and secondary electrons (9) of the incident electron beam (3); )
is a waveform converter connected to the output of this signal generator (10), <12> is a current amplifier connected between this waveform converter (11) and the deflection coil (6), and R1 is this current amplifier. (12) is a resistor connected between the deflection coil (6), R2 is a resistor connected between the collector (8) and ground, and (13) is connected to each end of the resistor R1. Weld line detection device together with the collector (8) has horizontal axis deflection terminals (13a) (13b) and vertical axis deflection terminals (13c), (13d) respectively connected to each end of resistor R2. Oscilloscope (14)
> is a bright spot appearing on the screen of this oscilloscope (13).

The conventional electron beam welding machine is operated as described above, and its operation will be explained in detail below.

In the electron beam welding machine shown in Fig. 3, a signal generator (10
The output of
After being amplified to a predetermined size, the deflection coil (6)
The signal across the resistor R1 is input to the horizontal axis deflection terminals (13a) and (13b) of the oscilloscope (13). On the other hand, the electron beam (3) is focused on the surface of the workpiece (4) by the focusing coil (5).
The welding line (
a) is scanned across the area.

In addition, the reflected electrons and secondary electrons (9) of the electron beam (3)
> is captured by the collector (8) and the signal across the resistor R2 is input to the vertical axis deflection terminals (13c) and (13d) of the oscilloscope (13). The signal generator (10) outputs a triangular waveform signal, and this signal is converted into a waveform as shown in FIG. 4 by a waveform converter (11). The waveform shown in FIG. 4 shows that each voltage zero point is for a time t,
It's stretched out. As a result, the point where the electron beam (3) is not deflected, that is, the point where the electron beam (3) is
), the voltage waveform on the oscilloscope (13) stops for time t in FIG. 5, and a bright spot (14) appears on the screen. Therefore, the amount of reflected electrons and secondary electrons (9) reaching the collector (8) is smaller than the welding line (
Using the decreasing feature at the position of bright point (14)
) and the peak point of the signal decrease from the collector (8), positioning will be achieved.

[Problems to be Solved by the Invention] Conventional electron beam processing machines do not have a means to detect that the electron beam has come off the workpiece, and the electron beam may melt the walls of the processing chamber, for example, the welding chamber. There was a problem.

This invention was made to solve these problems, and the object is to provide an electron beam processing machine that can not only detect processing lines but also detect when the electron beam has come off the workpiece. shall be.

[Means for Solving the Problems] The electron beam processing machine according to the present invention detects deviation of the electron beam from the workpiece by monitoring changes in the level of the detection waveform of the processing line detection device. It is equipped with a circuit.

[Function 5] This invention utilizes the fact that when the electron beam leaves the workpiece, the level of the detection waveform of the processing line detection device becomes extremely small.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. In FIG. 1 showing the schematic configuration of this embodiment, (1) to (
14) is exactly the same as that in the conventional example. 15
) is a misalignment detection circuit that is electrically connected to the oscilloscope (13) and detects that the electron beam (3) has come off the workpiece (4). Moreover, FIG. 2 is an explanatory diagram supplementary to the operation of the present invention, in which (16) is the wall of the welding room,
(17) is the off-target time, and break&i(3'), (4
'), (9'') indicate a missed result.

The electron beam processing machine, such as the electron beam welding machine, of the present invention is constructed as described above, and its operation will be described below.

As shown by the solid line in Figure 2 (.), when the electron beam (3) is welding the workpiece (4), a large amount of reflected electrons or secondary electrons (9) is generated, so As shown in Figure (h), the DC level of the detection wave 6 of the oscilloscope (13) is high. However, as shown by the broken line in Figure 2 (.), the electron beam (3゛) is When the object (4') deviates from the object (4'), the reflected electrons or secondary electrons (9') rapidly decrease in inverse proportion to the square of the distance, so the DC level of the detected waveform becomes low. ) is inspected by the misalignment detection circuit (15) shown in Fig. 1, and the electron beam (3
> can be stopped from occurring.

In the above embodiment, the present invention was applied to an electron beam welding machine, but the present invention may also be applied to other applications other than welding, such as cutting. Further, even if an XR sensor is used instead of the collector, the same effects as in the above embodiment can be obtained.

[Effects of the Invention] As described above, the present invention includes a misalignment detection circuit that monitors changes in the level of the detection waveform of the processing line detection device and detects that the electron beam has deviated from the workpiece. Therefore, by simply adding a simple misalignment detection circuit to a conventional electron beam processing machine, it is possible to prevent the wall of the processing chamber from melting, and the apparatus can be constructed at a low cost.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing an embodiment of an electron beam welding machine according to the present invention, Fig. 2 is a diagram showing the relationship between the movement of the workpiece and the DC level of the detected waveform, and Fig. 3 is a diagram showing the relationship between the movement of the workpiece and the DC level of the detected waveform. FIG. 4 is a schematic diagram showing the welding machine, and is a waveform diagram showing the voltage of the waveform converter. In the figure, (2) is an electron gun, (3) is an electron beam, (
4> is the object to be welded, (5) is the focusing coil, (6> is the deflection coil, (7) is the welding wire, (8> is the collector, <9> is the reflected electron or secondary electron, and (13) is the oscilloscope. ,(
15) is a misalignment detection circuit. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] (1) an electron beam generating means for generating an electron beam for processing a workpiece; an electron beam generating means disposed between the electron beam generating means and the workpiece; and focusing the electron beam on the workpiece; a focusing/deflecting means for scanning the electron beam across the machining line of the workpiece; a focusing/deflecting means disposed between the focusing/deflecting means and the workpiece; a processed line detection device that detects the processed line by capturing reflected electrons or secondary electrons;
The method further comprises a misalignment detection circuit that is electrically connected to the processed line detection device and monitors changes in the level of the detected waveform to detect that the electron beam has come off the workpiece. Electron beam processing machine.