JPH0244953Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a laser processing machine that detects the distance between the nozzle tip and the workpiece using a sensor, and moves and adjusts the nozzle height to keep the distance constant. The present invention relates to a nozzle moving device.

2. Description of the Related Art In laser processing, it is generally necessary to maintain a constant focal position of a laser beam on a workpiece.

For this reason, conventionally, the distance between the nozzle tip and the workpiece is detected by a sensor installed at or near the nozzle tip, and the nozzle, which holds the lens integrally, is moved up and down so that this distance remains constant. A method has been used to focus the laser beam on the workpiece surface.

At this time, it is necessary to move the nozzle quickly in order to cope with the workpiece surface whose height changes continuously depending on the shape of the workpiece. However, in the conventional method, a servo motor is used as a drive source to move the lens, and the sensor signal is affected by the rotor inertia of the motor, the acceleration/deceleration time constant, and the inertia of the drive member connected to the motor. It took a long time for the nozzle to actually move after it came out, and the response was very poor. For this reason, a time lag occurs in the movement of the nozzle, which poses a problem in processing.

Purpose of the invention and its solution The purpose of the invention is to provide a device with excellent responsiveness that does not require time from the signal of the sensor to the movement of the nozzle, and does not cause a time lag in the movement of the lens. Our goal is to provide the following.

For this purpose, the present invention uses a magnetic circuit formed by a permanent magnet and a coil as a driving source to move the nozzle.

Configuration of the Invention The configuration of the device of the present invention will be specifically explained below based on the drawings.

Reference numeral 1 denotes a holder main body that moves up and down according to program commands, etc., and 2 a nozzle holder that is held with respect to the holder main body 1 so as to be able to move up and down along the optical axis. Inside the holder body 1, an iron core 3 having a ring-like inverted L-shaped cross section and a permanent magnet 4 having a ring-like L-shaped cross-section are fixed to surround the optical path of the laser beam. . The coil 5 attached to the upper end of the nozzle holder 2, the permanent magnet 4, and the iron core 3 form a magnetic circuit 6 shown by a broken line in the figure. The holder main body 1 is made of a non-magnetic material to prevent magnetic leakage.

The nozzle holder 2 is made of an insulator and integrally holds a condensing lens 7 therein, and a nozzle 9 which also serves as a capacitance sensor 8 is attached to the tip.

This nozzle holder 2 is supported resiliently and vertically by two upper and lower flappers 10, 10 installed in the holder body 1.
The flapper 10 is formed, for example, in the shape of a ring with a corrugated cross section, and its outer edge is fixed to the holder main body 1 and its inner edge is fixed to the nozzle holder 2, respectively.

The coil 5 attached to the upper end of the nozzle holder 2 is inserted into the magnetic circuit 6, and the detection signal from the capacitance sensor 8 is passed through the capacitance detector 11 and the DC amplifier 12 to the holder body 1.
The electric current flows into the coil 5 through the plug 13 attached to the electric current and the lead wire 14, and the holder 2 is moved up and down according to the current value.

Further, a flange-shaped locking portion 2a is integrally formed to protrude from the outer peripheral portion of the nozzle holder 2, and a stopper 15 is provided on the holder body 1 so as to face downward from the locking portion 2a. This stopper 15 is formed integrally with a piston 17 that is fitted in a cylinder 16 formed at the lower part of the holder main body 1 so as to be able to slide vertically.
As shown in the figure, the nozzle holder 2 is normally held at the retracting limit position at a certain distance from the locking part 2a, as shown in the figure, by a compression spring 18 compressed between the nozzle 9 It is possible to move up and down in order to keep the distance h between the workpiece W and the workpiece W constant.

On the other hand, when teaching the cutting path of the workpiece W or when the nozzle 9 passes over a hole in the workpiece W, the sensor 8 is turned off and air is supplied into the cylinder 16 at the same time. There is. For this reason, the piston 17 has a spring 18
The shoulder portion of the stopper 15 is held at the forward limit position by being locked by the spring seat 20. Therefore, the stopper 15 is the locking portion 2
Since the nozzle holder 2 is held at a close position by the magnetic circuit 6, even if the nozzle holder 2 tries to descend suddenly into the hole, it is resiliently stopped by the stopper 15 and the lowering limit of the holder 2 is restricted. Ru. Thereby, the holder 2 can be reliably held in a safe lowered position. Note that 19 is an air vent hole opened in the side surface of the holder main body 1.

Effect of the invention With the above configuration, when the sensor 8 detects the capacitance between it and the workpiece W during machining, the signal flows to the coil 5 through the capacitance detector 11 and the DC amplifier 12, and is transmitted by the magnetic circuit 6. Holder 2 is gear up
is raised or lowered instantaneously to maintain a constant value. In this way, the timing of the detection by the sensor 8 and the timing of the movement of the holder 2 almost coincide, allowing a quick response.

Also, when the sensor 8 is turned off, such as during teaching, air is automatically flowed into the cylinder 16, the stopper 15 is pushed up, and the holder 2
It comes into contact with the locking part 2a of. Therefore, even if the capacitance measured by the sensor 8 becomes zero, the holder 2 is maintained at a safe lowering limit position without suddenly descending.

In the above embodiment, a capacitive sensor is used as the sensor 8, but the present invention is not limited to this, and a method of detecting the gap h using a magnetic sensor or other sensor is also possible.

Effects of the invention As explained above, the invention uses a magnetic circuit formed by a permanent magnet and a coil as the drive source for nozzle movement to maintain a constant distance between the nozzle tip and the workpiece, so the sensor There is no time lag from the signal until the nozzle moves, and it has excellent responsiveness.Furthermore, since a permanent magnet is built into the holder body, it has the effect of being compact in terms of structure and appearance.

Furthermore, by providing a stopper that regulates the lowering limit of the nozzle holder that operates when the sensor is OFF, it is possible to prevent the nozzle holder from descending suddenly and prevent collisions. It is possible to secure the nozzle at the lower limit position and maintain it in a safe state, such as when

[Brief explanation of drawings]

The figure is a vertical cross-sectional view of the device of the present invention. 1...Holder body, 2...Nozzle holder,
2a...Locking portion, 4...Permanent magnet, 5...Coil, 6...Magnetic circuit, 7...Condensing lens, 8...
Capacitance sensor, 9... nozzle, 15... stopper.

Claims (1)

[Claims for Utility Model Registration] (1) The nozzle tip has a sensor that detects the distance to the workpiece, and based on the detection signal from this sensor, the nozzle height is adjusted to reduce the distance between the nozzle tip and the workpiece. In a laser processing machine that is designed to be kept constant, a nozzle holder that integrally holds a condensing lens inside and has the above-mentioned nozzle at the tip is held movably up and down with respect to the holder body, and the upper end of this nozzle holder a coil electrically connected to the sensor,
A nozzle moving device for a laser processing machine, characterized in that a permanent magnet forming a magnetic circuit with the coil is built into the holder body, and the nozzle holder is driven up and down by the magnetic circuit. (2) A locking portion is provided on the outer periphery of the nozzle holder, and the head body is normally held in a position spaced downward from the locking portion, and when the sensor is turned off, it rises and comes into contact with the locking portion, thereby locking the nozzle. A nozzle moving device for a laser processing machine according to claim 1, characterized in that the device has a stopper for regulating the lowering limit of the holder.