RU2266802C2 - Contact laser working apparatus - Google Patents

Abstract

FIELD: machine engineering, possibly laser cutting of different materials.

SUBSTANCE: apparatus includes optical laser head, probe, displacement pickup. The last is in the form of digital signal source having two spring-loaded one relative to other separate plates. Probe includes regulated along height rod joined with one of said plates. One plate is spring-loaded by means of reverse-action springs mounted in rod; other plate is spring-loaded by means of lead screw mounted in head. Apparatus provides continuous conversion of analog signals to digital ones.

EFFECT: enhanced accuracy and efficiency of working blanks due to continuous measurement of distance between focal point of optical laser head and worked surface.

1 cl, 1 dwg

Description

The invention relates to mechanical engineering and can be used for laser cutting of various materials.

Devices are currently known in which contact measurements of the distance between the laser optical head and the workpiece surface to be processed are supported by sensors and are carried out either by changing the focal length or by moving the optical head at a constant focal length.

A device for contact laser processing, comprising an optical laser head, a probe in contact with the workpiece surface, an analog sensor for displacing the laser optical head (ed. St. 60-44-191 Japan (UR) F, MKI 4 V 23 K 26/02, UDC 621.98 (43), publ. 09.03.85).

Measurements of the distance between the laser optical head and the surface being processed are made on the basis of analog electrical signals that arise as a result of elastic deformations in the sensor when one probe assembly is offset from another.

A disadvantage of the known device is, firstly, the small range of measurements of the distance between the optical head and the workpiece, secondly, the need to convert the signal shape of the displacement sensor from analog to digital for technical and information matching of the device with CNC systems, insufficient accuracy and productivity of processing the workpiece .

The objective of the proposed technical solution is to increase the accuracy and productivity of processing the workpiece by converting the waveform from analog to digital.

The problem is achieved in that in the device for contact laser processing, containing an optical laser head, probe, displacement sensor, the sensor is made in the form of a digital signal source having two discrete plates spring-loaded relative to each other, and the probe is equipped with a height-adjustable rod, through which it is connected to one of the plates, with one plate being spring-loaded with reverse-acting springs mounted on the rod, and the other plate being spring-loaded with a lead screw mounted on the head.

The invention is illustrated in the drawing, which shows a diagram of a General view of the device.

The device comprises a laser optical head 1 with a focusing lens 2. A hole 3 for supplying a working gas, for example oxygen, is made in the optical head, and the nozzle 4 of the head has a hole 5 for outputting laser radiation (a laser source is not shown). The optical head is inserted into the sleeve 6, on one of the sides of which the bracket 7 is rigidly fixed, carrying a discrete displacement sensor. The design of the discrete sensor is two parallel plates. One 8 plate is rigidly fixed to the bracket and is stationary, the other plate 9 with the help of a fixed sleeve 10 is mounted on a spring 12 mounted in the bracket rod 12 and monitors its movement. Both plates are included in the conversion and digitalization of information on the movement of the optical head. A screw 13 is installed in the bracket to limit the stroke of the rod down below the maximum permissible level and an adjustment screw 14 connected to the sleeve by a spring 15, which is identical in force to the spring 11, but with a reverse action. A flexible probe 16 is installed on the free end of the rod, in which a hole 18 is made to contact the surface of the workpiece 17 to be aligned with the laser optical axis 19 (or with the center of the hole in the nozzle of the laser optical head for laser radiation output).

Structurally, the optical head with the sensor is mounted in a stationary cylindrical body 20 and is connected through a lead screw 21 with an electric motor 22.

The device operates as follows.

Before starting work, using the adjusting screw 14, overcoming the forces of both springs 11 and 15, lower the rod 12 down until the sleeve 10 contacts the screw 13, which will correspond to the predetermined maximum permissible lower value of the movable plate 9 of the discrete sensor with respect to the fixed plate 8. In this case, the lower position of the probe is not important.

The workpiece 17 is installed under the optical head 1 of the laser. The electric motor 22 is turned on, which causes the rotation of the spindle 21 and, accordingly, the optical head 1 moves downward until the opening 18 of the probe 16 comes into contact with the surface of the workpiece 17. When touching the surface of the workpiece, acting on the rod due to its elasticity, the probe will overcome the compression force springs 11, move the rod up. Accordingly, there is a relative displacement of the two plates of the discrete sensor, maintaining the initial focal position f on the surface of the part that is constantly set in advance (not shown) by CNC. Due to the equal forces of the oppositely directed springs, the position of both sensor plates will be balanced.

Next, surface treatment is performed. In the treatment zone through the nozzle 4 serves focused laser radiation with a given focal length f, and through the hole 3 a gas stream. Then carry out the relative movement of the laser optical head over the surface of the workpiece along the processing plane, being in the focus of the optical system. With a constant distance between the processed surface and the focus, the relative position of both plates of the discrete sensor is constant, respectively, there are no signals about the movement of the optical head 1.

If there are irregularities on the treated surface (troughs, protrusions, etc.), the probe, constantly pressed to the workpiece by the force of the spring 11, moves accordingly up and down. Together with the rod, the sensor plate 9 also receives movement, which is accompanied by the formation of pulses at the output of the fixed plate 8, the number of which is proportional to the amount of movement. The pulses of the sensor enter the CNC system, where, according to standard control algorithms, the laser focal point is moved, which leads to the rotation of the spindle, which will compensate for the change in the relative position of both plates in order to restore the original focal position.

If in the processing program it is necessary to programmatically change the initial focal position of the laser optical head relative to the surface being machined, then through the CNC system this change is also carried out according to standard control algorithms, using signals from the sensor along the vertical coordinate of the machine due to the rotation of the spindle by an electric motor.

The device, intended for use as part of the CNC laser system, allows for program-adaptive control of the focal position of the focal optical head of the laser relative to the workpiece surface, as well as the processing of workpieces with high accuracy and productivity.

Claims (1)

Device for contact laser processing, containing an optical laser head, probe, displacement sensor, characterized in that the sensor is made in the form of a digital signal source having two discrete plates spring-loaded relative to each other, and the probe is equipped with a height-adjustable rod through which it is connected to one of the plates, moreover, one plate is spring-loaded with reverse-acting springs mounted on the rod, and the other plate is spring-loaded with a lead screw mounted on the head.