Abstract: A laser machining apparatus in which laser output can be easily corrected in view of secular change of components of the laser machining apparatus and influence of temperature. Output values of a laser oscillator operated according to a reference laser output command value Psc are stored as reference output values P(?) at different temperatures ? in a table TB1. When the laser oscillator is started up, a measured output value Pr of the laser oscillator supplied with the reference command value Psc is obtained, and a new correction coefficient k is obtained to replace an old one. From a reference output value P(?) at a temperature at that time and the actual output measured value Pr, a correction value ?P is obtained and stored.

Abstract: An apparatus and a method for laser machining with a gap or tracing control, capable of shortening time required for moving a machining head from a machining end point of one machining shape to a machining start point of next machining shape. The laser machining is performed with the gap or tracing control in which a gap amount between the machining nozzle and the workpiece is controlled to be constant. Driving of a Z-axis is started at a predetermined velocity when the machining nozzle reaches a machining end point of one machining shape. In the drive of the Z-axis, when the Z-axis is driven by a predetermined amount, driving of an X-axis and a Y-axis is started so that the machining nozzle moves to the next machining start point by rapid traverse. A direction of driving of the Z-axis is reversed at a middle point between the machining end point and the machining start point. The driving of the Z-axis may be discontinued at a retreated point.

Abstract: A laser machining apparatus capable of effecting a feedback control of a laser output from an early stage of operation and detecting an abnormality of the laser output quickly and precisely. A laser output command issued from a laser output commanding section is subjected to a feedback control and inputted to a laser pumping power supply for a laser oscillator. An output of a laser power sensor is amplified by an amplifier and compared with an output of a measurement simulating section for estimating the measured value of the laser output. A difference of the measured value and the simulated value of the laser output is inputted to the feedback control section and also to an output abnormality detecting section. A measurement input estimating section calculates an average power which should be outputted in a normal condition of the laser machining based on data of the laser output command. A fist order delay system can be adopted as the measurement simulating section.

Abstract: A laser machining apparatus in which laser output can be easily corrected in view of secular change of components of the laser machining apparatus and influence of temperature. Output values of a laser oscillator operated according to a reference laser output command value Psc are stored as reference output values P(&thgr;) at different temperatures &thgr; in a table TB1. When the laser oscillator is started up, a measured output value Pr of the laser oscillator supplied with the reference command value Psc is obtained, and a new correction coefficient k is obtained to replace an old one. From a reference output value P(&thgr;) at a temperature at that time and the actual output measured value Pr, a correction value &Dgr;P is obtained and stored.

Abstract: A laser machining apparatus capable of effecting a feedback control of a laser output from an early stage of operation and detecting an abnormality of the laser output quickly and precisely. A laser output command issued from a laser output commanding section is subjected to a feedback control and inputted to a laser pumping power supply for a laser oscillator. An output of a laser power sensor is amplified by an amplifier and compared with an output of a measurement simulating section for estimating the measured value of the laser output. A difference of the measured value and the simulated value of the laser output is inputted to the feedback control section and also to an output abnormality detecting section. A measurement input estimating section calculates an average power which should be outputted in a normal condition of the laser machining based on data of the laser output command. A fist order delay system can be adopted as the measurement simulating section.

Abstract: An apparatus and a method for laser machining with a gap or tracing control, capable of shortening time required for moving a machining head from a machining end point of one machining shape to a machining start point of next machining shape. The laser machining is performed with the gap or tracing control in which a gap amount between the machining nozzle and the workpiece is controlled to be constant. Driving of a Z-axis is started at a predetermined velocity when the machining nozzle reaches a machining end point of one machining shape. In the drive of the Z-axis, when the Z-axis is driven by a predetermined amount, driving of an X-axis and a Y-axis is started so that the machining nozzle moves to the next machining start point by rapid traverse. A direction of driving of the Z-axis is reversed at a middle point between the machining end point and the machining start point. The driving of the Z-axis may be discontinued at a retreated point.

Abstract: A laser output control system responsive to a command signal from a CNC, which is capable of sharply reducing time required for transfer of waveform data from the CNC in executing laser-beam machining. An output control device, upon receiving the command signal from the CNC, reads registration data and a set of waveform data stored in advance in one of the registers and a memory of an output control circuit, respectively, and then multiplies a peak value of a specified set of waveform data by a waveform scale factor and an override value set in advance to a PMC to form the waveform data into a waveform having a desired peak value. Then, by the use of a frequency and the number of times of output of the registration data, a repetition period and the number of repetitions of the set of waveform data are determined. The output control device delivers an output waveform thus determined to a power supply for a laser oscillator.

Abstract: A laser beam machine capable of easily generating a machining path for cutting. A reading device reads a designation code for the shape of a hole to be cut, a size of the hole, a central position of the hole, and a start position and a final stop position of a front end point of a machining head. A smooth path-generating device generates a smooth path from the designation code for the shape of the hole, the size of the hole, the central position of the hole, and the start position and the final stop position, such that the overall path for the front end point of the machining head becomes a smooth one. A machining program-generating device generates a machining program based on the smooth path generated. According to the machining program, the machining head moves to cut the hole through a workpiece.

Abstract: A laser machining resuming method in which the laser machining can be securely resumed without leaving an un-machined portion when machining is interrupted while laser machining is being carried out. When laser machining is performed a distance of L.sub.0 from a machining point (P1) and abnormal machining is sensed at a machining point (P3), a CNC starts a retry processing in response to an abnormal machining sensing signal. That is, first, the laser machining is stopped and the position of the machining point (P3) at the time is stored. Next, the machining head is retracted a distance h.sub.0 in a Z-axis direction and moved backward a distance L.sub.2 along a machining path L having been executed until that time. When the backward movement is completed at a point (P6), a gap between a nozzle and a workpiece is controlled, and the laser machining is resumed on the completion of the approach.

Abstract: Oxygen is mixed with another gas to form an auxiliary gas that will permit a welding of zinc-plated steel sheets (3a and 3b) without producing blowholes. An oxygen (O.sub.2) gas cylinder (4a) is provided in addition to an argon (Ar) gas cylinder (4b), for forming the mixed auxiliary gas, and the argon gas and the oxygen gas are mixed in a mixer (6) before being supplied to a machining head (7) and jetted onto a machining spot (9) through a nozzle (8). The oxygen oxidizes the zinc of the zinc-plated steel sheets (3a and 3b) to produce zinc oxide and zinc peroxide, to thereby prevent evaporation and minimize spatters, and thus permits a laser welding with a minimum generation of blowholes.

Abstract: A piercing method using a laser, in which the processing time is made shorter; a thermal runaway is prevented; and dispersion of the processing time is made smaller. According to this method, piercing operation is started with an initial pulse frequency P.sub.0 and an initial pulse duty ratio Q.sub.0, and the pulse frequency and the pulse duty ratio are increased by increments P and Q, respectively, with every passage of a predetermined time T. The pulse frequency and the pulse duty ratio are increased by stages. After this increase is repeated a predetermined number of times, or after the passage of a predetermined time from the start of processing, processing is continued to the end maintaining the increased values. This piercing method enables the processing time to be reduced to 1/3 to 1/5, as compared with the conventional method. In addition, this method prevents a thermal runaway, and reduces the dispersion of the processing time.

Abstract: A maintenance schedule monitoring device is provided for a laser beam machine system, which is designed to monitor the maintenance schedule of the laser beam machine system. A time measuring unit (A) measures the time for which an object requiring maintenance is operating, according to information on the operation of the object requiring maintenance in the laser beam machine system. A time alarm unit (B) detects that the measured time has reached a preset time, and causes a maintenance schedule display control unit (C) to display an instruction that it is time to carry out a maintenance of the object, on a display unit (D). Thus, the maintenance and inspection schedule of the object requiring maintenance is automatically managed by automatic chronological time measurement, and when it is time to carry out the maintenance and inspection, an indication that it is time to carry out the maintenance of the object requiring maintenance is automatically shown on the display unit (D).

Abstract: An apparatus in which the length of a propagation path from a laser oscillator (6) to condensing means (a6) of a processing head (5), that is, the optical path length, in a laser processing machine (1), can be freely fixed to a set value. In the laser processing machine (1) of a multi-axis control type designed so that the processing head (5) is driven in the directions of a plurality of axes (X, Y and Z axes) with respect to the body of the laser processing machine by means of head drive means, an optical path length expansion mechanism for extending or contracting the length of an optical path from the laser oscillator (6) to the condensing means (a6) independently of the motion of the processing head (5) is inserted in the middle of the propagation path. For the optical path length expansion mechanism, optical path length control means is combined with optical path length setting means.

Abstract: Surface-treated metallic workpieces such as zinc-plated steel plates are welded with high quality while they are being held in intimate contact with each other. An auxiliary gas including an oxygen gas is ejected from a space (7) around an electrode (1) through a nozzle (8) to a welding point (9) on overlapping surface-treated metallic workpieces such as zinc-plated steel plates (3a, 3b). When the zinc-plated steel plates (3a, 3b) are welded in the atmosphere of the auxiliary gas, the surface layers of zinc and oxygen react with each other, producing a solid oxide such as zinc oxide or zinc peroxide. Therefore, a gas such as a zinc vapor is prevented from being produced between the overlapping zinc-plated steel plates (3a, 3b). The welded joint is of high quality without blowholes which would otherwise blow away molten steel.

Abstract: A laser beam machining method for cutting a workpiece in accordance with a machining program composed of a succession of move commands and laser output commands. An angle of a machining path is calculated on the basis of a move command under execution and a subsequent read out move command (S2, S3). The angle of the machining path is compared with a preset angle (S4), and when the angle of the machining path is more acute than the preset angle, the movement for machining based on the move command under execution is decelerated and stopped (S5). In this case, the laser output command is changed from a cutting condition to a piercing condition, to carry out a piercing operation, and when the piercing operation is completed, the movement for machining is restarted in accordance with the subsequent move command. When the movement for machining is restarted, the laser output command is changed from the piercing condition to the cutting condition in accordance with the movement for machining.

Abstract: An electric discharge tube for a gas laser in which a laser gas flow axis and a laser oscillation optical axis are coaxial and a discharge direction of discharge pumping is perpendicular to those axes. The internal sectional form of a discharge tube (1) perpendicular to the laser oscillation optical axis is made rectangular and the internal diameter of nondischarge sections (10a, 10b) is made larger than the diagonal line of the discharge tube (1). The section of laser beams generated in a rectangular discharge region (11) becomes substantially rectangular in shape and the laser beams are externally output intact, whereby a substantially rectangular beam mode is obtained.

Abstract: A discharge tube for a high-speed axial-flow type discharge pumping gas laser device is provided, in which a capacitive load medium (9) under metal electrodes (2a, 2b) has convexly curved faces opposed to each other and constitutes a discharge tube. With this construction, the distribution of a laser oscillation gain within the discharge tube (1) is made uniform, and a single-mode laser beam is obtained.

Abstract: A laser gas displacement amount control method for controlling the amount of displacement of a laser gas in a discharge pumping type gas laser device. The laser gas in a discharge tube is displaced with a predetermined displacement amount during a fixed period immediately after starting during which a beam-output correction is effected, and the laser gas is displaced with a displacement amount smaller than the predetermined displacement amount during the operation period thereafter. Since this smaller displacement amount can be made less than one-tenth of the predetermined displacement amount required during the fixed period immediately after starting, the amount of consumption of the laser gas can be reduced.

Abstract: An NC laser device is provided which is a combination of a gas laser oscillator having a cooling mechanism for forcibly cooling a laser gas by a blower and a cooling unit, and a numerical control device. The NC laser device includes a gas temperature measuring device for measuring a gas temperature at an inlet of the blower, a casing temperature measuring device for measuring a temperature of a casing of the blower, and an abnormality detecting device, etc. The abnormality detecting device detects an abnormal state of the cooling mechanism, and stops the operation of the gas laser oscillator, when the inlet gas temperature or the casing temperature becomes higher than the respective reference value. Accordingly, an abnormal state of the cooling mechanism can be detected at an early stage, and thus secondary damage to the blower can be prevented.

Abstract: A three-dimensional shape machining laser device for performing three-dimensional machining. The device comprises a teaching box (20) for teaching NC commands, a sensor (43) for detecting the distance between the distal end of a nozzle and a work, a control apparatus (10) which includes command storage apparatus for storing the NC commands, NC command execution apparatus for executing the NC commands, tracing apparatus for controlling the gap between the nozzle and the work to a predetermined value, interrupt control apparatus for interrupting the execution of an NC command program, correction value calculation apparatus for calculating correction command values used for correcting coordinate values, and correction apparatus for correcting command values in accordance with the correction command values, etc.