Abstract: In a main circuit 11 of the plasma cutter power supply device 6, a plurality of DC power units 14-1, . . . 14-n of low capacity are connected in parallel on their DC output sides, and are connected to a plasma torch 20. Each power unit 14-1, . . . 14-n can operate asynchronously and independently from each other. The power supply control device 6 controls the number of power units to be operated, and the intensity of output electrical current at which each of them is to be operated, according to the cutting conditions (the nature of the material to be cut, its thickness, and the cutting speed) and according to the number of power units which can be operated. If some of the power units are faulty, the power supply control device 6 controls the cutting conditions which can be accepted, according to the number of normal power units.

Abstract: A cutting machine secures safety of a worker during movement of a head without lowering production efficiency. When moving a cutting head without cutting material to be cut upon a table, a moving truck and the cutting head are moved at a higher speed as compared with when cutting the material to be cut. If, when the moving truck and the cutting head are moving at high speed, a worker who is present upon the table intercepts either of light beams which are located in front of and behind a horizontal beam, then this movement speed is decelerated to a safe low speed, but the task of cutting the material is not interrupted. Subsequently, when the worker approaches the horizontal beam closer, and contacts a wire or a bar in the vicinity of the horizontal beam, movement of the moving truck and the cutting head is forcibly stopped.

Abstract: A plasma cutting device performs cutting in a plurality of stages. In a first cutting sub-process, a manufactured product is cut out from a base material upon a stage according to an NC program. Next, images of respective regions in the vicinities of proper positions at two corner points of the manufactured product which has been cut out are photographed by an image sensor, the actual positions of these two corner points of the manufactured product are detected from these images which have been photographed, and the translation distances and the rotational angle between the actual positions which have been detected and the proper positions are calculated. The NC program is corrected. And, in a subsequent cutting sub-process, additional cutting for beveling is carried out upon cutting surfaces at the outer circumference of the manufactured product, according to the corrected NC program.

Abstract: A plasma cutting device performs cutting in a plurality of stages. In a first cutting sub-process, a manufactured product is cut out from a base material upon a stage according to an NC program. Next, images of respective regions in the vicinities of proper positions at two corner points of the manufactured product which has been cut out are photographed by an image sensor, the actual positions of these two corner points of the manufactured product are detected from these images which have been photographed, and the translation distances and the rotational angle between the actual positions which have been detected and the proper positions are calculated. The NC program is corrected. And, in a subsequent cutting sub-process, additional cutting for beveling is carried out upon cutting surfaces at the outer circumference of the manufactured product, according to the corrected NC program.

Abstract: A cutting machine secures safety of a worker during movement of a head without lowering production efficiency. When moving a cutting head without cutting material to be cut upon a table, a moving truck and the cutting head are moved at a higher speed as compared with when cutting the material to be cut. If, when the moving truck and the cutting head are moving at high speed, a worker who is present upon the table intercepts either of light beams which are located in front of and behind a horizontal beam, then this movement speed is decelerated to a safe low speed, but the task of cutting the material is not interrupted. Subsequently, when the worker approaches the horizontal beam closer, and contacts a wire or a bar in the vicinity of the horizontal beam, movement of the moving truck and the cutting head is forcibly stopped.

Abstract: In a main circuit 11 of the plasma cutter power supply device 6, a plurality of DC power units 14-1, . . . 14-n of low capacity are connected in parallel on their DC output sides, and are connected to a plasma torch 20. Each power unit 14-1, . . . 14-n can operate asynchronously and independently from each other. The power supply control device 6 controls the number of power units to be operated, and the intensity of output electrical current at which each of them is to be operated, according to the cutting conditions (the nature of the material to be cut, its thickness, and the cutting speed) and according to the number of power units which can be operated. If some of the power units are faulty, the power supply control device 6 controls the cutting conditions which can be accepted, according to the number of normal power units.

Abstract: A plasma cutting machine is provided in which a dross adhesion inhibitor is jetted from a plasma torch toward the cutting start position (piercing position) of the object material. A dross adhesion inhibitor supply flow path for feeding the dross adhesion inhibitor is connected to an assist gas feeding line in which an assist gas for assisting cutting of the object material with the plasma arc flows.

Abstract: A plasma processing apparatus capable of making an accurate lifetime assessment for each of plural consumable parts (the definition of “the consumable part” is an electrode and/or a nozzle) so that effective use of the consumable parts becomes possible leading to reduced running cost. In the plasma processing apparatus, a plasma arc is generated from a plasma torch composed of an electrode and a nozzle to perform plasma work on a workpiece. Such a plasma processing apparatus includes a plurality of consumable parts, each consumable part being an electrode and/or a nozzle, and further comprises a memory for storing consumption data on every consumable part, the consumption data being used for calculation of consumption; and a display unit for displaying consumption calculated by a CPU for selecting the consumption data corresponding to a consumable part in use.

Abstract: A main arc ignition method capable of extending lives of a plasma electrode and a nozzle. For this purpose, before or immediately after starting arc, a plasma torch is supplied with a plasma gas at least either at a lower flow rate or at lower gas pressure; the plasma gas is switched to a gas flow rate and gas pressure of a time of cutting a work, after pilot arc is ignited between an electrode and a nozzle, or after main arc is ignited between the electrode and the work; and when generation of the main arc between the electrode and the work is detected, a pilot current is interrupted promptly by a semiconductor switch which is interposed in series with a resistance, in a pilot current circuit that is connected to the nozzle and supplies the pilot current to the pilot arc.

Abstract: Not only damage to a nozzle caused by spatter generated during piercing is prevented but also the deterioration of the nozzle owing to a pilot arc is restrained, whereby the service life of the nozzle is significantly increased. To this end, the plasma torch is positioned at an initial level which is the distance between the plasma torch and a steel plate when generating a plasma arc to start piercing operation and which has been set equal to a cutting level which is the distance between the plasma torch and the steel plate when carrying out cutting operation. After generation of the plasma arc, the plasma torch is immediately raised to a piercing level which is more distant from the steel plate W than the initial level and piercing operation is performed at the piercing level. After completion of the piercing operation, the plasma torch is lowered to the cutting level to start cutting operation. Just after transfer from a pilot arc into a main arc, a pilot current is cut off by turning a transistor off.

Abstract: A plasma processing apparatus capable of making an accurate lifetime assessment for each of plural consumable parts (the definition of “the consumable part” is an electrode and/or a nozzle) so that effective use of the consumable parts becomes possible leading to reduced running cost. In the plasma processing apparatus, a plasma arc is generated from a plasma torch composed of an electrode and a nozzle to perform plasma work on a workpiece. Such a plasma processing apparatus includes a plurality of consumable parts, each consumable part being an electrode and/or a nozzle, and further comprises a memory for storing consumption data on every consumable part, the consumption data being used for calculation of consumption; and a display unit for displaying consumption calculated by a CPU for selecting the consumption data corresponding to a consumable part in use.

Abstract: Not only damage to a nozzle caused by spatter generated during piercing is prevented but also the deterioration of the nozzle owing to a pilot arc is restrained, whereby the service life of the nozzle is significantly increased. To this end, the plasma torch is positioned at an initial level which is the distance between the plasma torch and a steel plate when generating a plasma arc to start piercing operation and which has been set equal to a cutting level which is the distance between the plasma torch and the steel plate when carrying out cutting operation. After generation of the plasma arc, the plasma torch is immediately raised to a piercing level which is more distant from the steel plate W than the initial level and piercing operation is performed at the piercing level. After completion of the piercing operation, the plasma torch is lowered to the cutting level to start cutting operation. Just after transfer from a pilot arc into a main arc, a pilot current is cut off by turning a transistor off.

Abstract: With reliable application of a necessary amount of dross adhesion inhibitor to a cutting start position of an object material, adhesion and deposition of dross is prevented, improved productivity is attained by reducing the cycle time, and a reduction in the running cost as well as man power and improved reliability are achieved. To this end, a plasma cutting machine has a jetting means for jetting the dross adhesion inhibitor toward the cutting start position (piercing position) of the object material W from a plasma torch used for generating the plasma arc. This jetting means is constructed such that a dross adhesion inhibitor supply flow path for feeding the dross adhesion inhibitor is connected to an assist gas feeding line in which an assist gas for assisting cutting of the object material W carried out with the plasma arc flows after jetted along the plasma arc.

Abstract: A main arc ignition method capable of extending lives of a plasma electrode and a nozzle. For this purpose, before or immediately after starting arc, a plasma torch is supplied with a plasma gas at least either at a lower flow rate or at lower gas pressure; the plasma gas is switched to a gas flow rate and gas pressure of a time of cutting a work, after pilot arc is ignited between an electrode and a nozzle, or after main arc is ignited between the electrode and the work; and when generation of the main arc between the electrode and the work is detected, a pilot current is interrupted promptly by a semiconductor switch which is interposed in series with a resistance, in a pilot current circuit that is connected to the nozzle and supplies the pilot current to the pilot arc.