Komatsu Industries Corporation

Komatsu Corporation

Tetsuya Kabata

Yoshihiro Yamaguchi

Takahiro Iriyama

Kazuhiro Kuraoka

Ikuo Kamada

Kenichi Nishihara

A hybrid thermal cutting apparatus has both a laser head and a plasma torch, both of which can be controlled independently, can perform both laser processing and plasma processing, thus reducing the running costs. A large number of cutting lines for cutting out various types of manufactured products from plate materials are classified into a laser cutting type and a plasma cutting type, according to the cutting length, whether they are the external periphery of manufactured products or apertures, the size of the manufactured products or the apertures, the required process accuracy, the plate thickness, or the like. The lines of the laser cutting type are cut by laser processing, while the lines of the plasma cutting type are cut by plasma processing.

Hybrid thermal cutting apparatus

Cutting quality of the product, in particular, hole cutting quality, in plasma arc cutting is improved. A control unit, which controls a plasma cutting apparatus for cutting a product from a plate material by moving a plasma torch at a cutting speed along a cutting path corresponding to the product shape to cut the plate material, while supplying an arc current and a plasma gas to the plasma torch and forming a plasma arc from a nozzle of the plasma torch to the plate material, conducts control so that, when a hole is cut, a cutting speed is lower, a value of the arc current value is smaller, and a plasma gas flow rate or pressure is less than those when a contour is cut.

Plasma cutting apparatus and control unit thereof

A thermal cutting machine and a cutting method using the same are described, which employ a simple, long-life torch hood for effectively shutting off spatter, the torch hood enabling easy supervision of the cut condition of a workpiece and easy replacement of the consumable parts of the torch. In the thermal cutting machine for cutting a metal by a plasma arc or laser beam generated from the torch, a hood liftable by an actuator is disposed so as to surround the torch and a control unit is provided for giving an instruction to the actuator to lower the hood to a torch-shielding position.

Thermal cutting machine and cutting method using same

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.

Plasma cutting process and machine

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.

Main arc ignition device and main arc ignition control method of plasma cutting machine

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.

Plasma processing apparatus for monitoring and storing lifetime usage data of a plurality of interchangeable parts

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.

Plasma arc machining method

A thermal cutting machine and a dust collecting method capable of reducing in size and exhausting fumes and a high pressure gas efficiently. For this purpose, the thermal cutting machine includes a plurality of exhaust chambers ( ) which are placed side by side inside a table ( ), an exhaust port ( ) provided at one end side of each of the exhaust chambers, an exhaust device ( ) communicating with each of the exhaust ports, an opening and closing drive device ( ) for opening and closing each of the exhaust ports, an air blow port ( ) provided at a position substantially opposing each of the exhaust ports, an air blow device ( ) which blows air into the each air blow port ( ), and a control device ( ) for controlling the opening and closing drive device and the air blow device in synchronism with each other, or controlling them individually, correspondingly to a horizontal position of a torch ( ) which is under cutting operation.

Thermal cutting machine and dust collecting method thereof

The invention prolongs the electrode lifetime of plasma machining electrodes having a hafnium or zirconium insert. A hafnium or zirconium insert inserted into the tip of a copper holder protrudes from the tip of the copper holder . The protrusion length L is not larger than the diameter D of the insert, preferably not larger than 0.5 mm. The protruding portion of the insert has a rounded section without sharp angles. The rear surface of the insert is exposed to the flow of the cooling water inside the electrode. At least during the generation of the pilot arc, a plasma gas containing at least 5 mol % nitrogen is used.

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Kaga, Japan

Tetsuya Kabata