Mitsubishi Electric Corporation

Nippon Steel Stainless Steel Corporation

Kazunari Morita

Hiroki Hikosaka

Yasuo Onodera

Hidetaka Katougi

Hiroshi Ukai

Shun Saito

Shiro Sasaki

Hiroshi Morikawa

Yasuhiro Ehara

Hiroshi Yoshikawa

Yuki Iwabuchi

The present invention is a power supply control apparatus that controls pulse discharge occurring in a machining gap in an electric discharge machine. The power supply control apparatus includes: a voltage level detecting device that detects the voltage level of a discharge voltage generated in the machining gap; a voltage level comparator hat compares the voltage level with a voltage level reference value, and outputs a comparison result; and a determining unit that, on the basis of the comparison result, determines whether a discharge pulse is abnormal in a designated one of a plurality of determination modes. The determination method can be designated during machining.

Power supply control apparatus of electric discharge machine

A method for producing an austenitic stainless steel slab by continuous casting of an austenitic stainless steel, including applying electric power to the molten steel in a depth region providing a solidification shell thickness of from 5 to 10 mm at least at a center position in the long edge direction, so as to cause flows in directions inverse to each other in the long edge direction on both long edge sides, thereby performing electro-magnetic stirring (EMS) to control a continuous casting condition satisfying 10&#x3c;&#x394;T&#x3c;50&#xd7;F+10. Herein, &#x394;T represents a difference between an average molten steel temperature (&#xb0; C.) and a solidification starting temperature (&#xb0; C.) of the molten steel, and Frepresents a stirring intensity index shown by a function of a molten steel flow velocity in the long edge direction imparted by the electro-magnetic stirring and a casting velocity.

Method for producing austenite stainless steel slab

A continuous casting method includes discharging a molten steel from discharge ports of a submerged nozzle under conditions (A) and (B); and performing electro-magnetic stirrer (EMS) to cause flows in directions inverse to each other in the long edge direction on both long edge sides in the molten steel in a region having a depth providing a thickness of a solidification shell of from 5 to 10 mm at least at a center position in the long edge direction. (A) a discharge extended line from the discharge port of the submerged nozzle intersects a molten steel surface in the mold at a point P, and the position of the point P satisfies 0.15&#x2264;M/W&#x2264;0.45; and (B) a condition satisfying 0&#x2264;L&#x2212;0.17Vi&#x2264;350, wherein the unit for L is mm, and Vi represents a discharge velocity (mm/s) of the molten steel at the outlet opening.

Continuous casting method

An electric discharge machine includes an electrode, a shaft-feed driving unit that, a voltage/current applying unit, a shaft-feed control unit that causes the shaft-feed driving unit to perform a jump operation, and a machining-condition setting and changing unit that sets a voltage applied between the electrode and a workpiece and an electric current flowing between the electrode and the workpiece. The machining-condition setting and changing unit determines whether the electric discharge between the electrode and the workpiece stabilizes after the jump operation ends and, in at least a part of a period before determining that the electric discharge stabilizes, sets at least one of the voltage and the electric current to a condition in which electric discharge more easily occurs than in the condition in applying the electric discharge machining.

Electric discharge machine

An electric discharge machining system is provided which distinguishes an abnormal discharge caused by an immediate discharge and an abnormal discharge caused not by the immediate discharge to suitably control in each case. The electric discharge machining system according to the present invention that machines a workpiece by producing a discharge between an electrode and the workpiece, includes: a no-load-time detection means that detects no-load time of inter-electrode voltage between the electrode and the workpiece; an immediate-discharge determination means that compares the no-load time detected by the no-load-time detection means with predetermined time to determine whether or not the discharge is an immediate discharge; a voltage detection means that detects the inter-electrode voltage; an abnormal-discharge determination means that compares the voltage detected by the voltage detection means with a predetermined value to determine whether or not the discharge is a normal discharge; a discharge state assessment means that assesses a state of the discharge on the basis of the determination result of the immediate-discharge determination means and the determination result of the abnormal-discharge determination means; and a machining condition control means that controls a machining condition on the basis of the discharge state assessed by the discharge state assessment means.

Electric discharge machining system

An electric-discharge machining device including an electric-discharge-state determination unit that determines whether an electric discharging state between a machining electrode and a workpiece is either a state of normal electric discharge or of abnormal electric discharge, and a machining-condition switching unit that changes at least one machining condition, further includes a storage unit that stores therein an electric-discharge-state determination indicator, a standard-deviation calculation unit, and a boundary calculation unit that calculates a boundary to be applied to a determination in the electric-discharge-state determination unit based on the electric-discharge-state determination indicator, wherein the machining-condition switching unit changes the machining condition according to a comparison result between the standard deviation calculated by the standard-deviation calculation unit and a standard deviation reference set as a reference of the standard deviation.

Electric-discharge machining device

A controller of an electrical discharge machine comprises: a control unit that controls a machining condition set by the electrical discharge machine; an acquisition unit that acquires a parameter indicating an electrical discharge state between poles in a state where the machining condition is controlled by the control unit so that a normal electrical discharge occurs between the poles; an arithmetic unit that obtains a probability density distribution of the acquired parameter; a decision unit that decides a threshold that specifies a boundary between a normal electrical discharge and an abnormal electrical discharge between the poles based on the obtained probability density distribution; and a discrimination unit that discriminates whether the electrical discharge state between the poles is normal or abnormal by using the decided threshold, and wherein the control unit controls the machining condition based on a discrimination result of the discrimination unit.

Controller of electrical discharge machine

A power-supply control device includes a high-frequency component detecting unit, a machining voltage level detecting device, a no-load time detecting device, and a pulse control device. The high-frequency component detecting unit detects a high-frequency component of discharge voltage at a machining gap. The machining voltage level detecting device detects a discharge voltage level at the machining gap. The no-load time detecting device detects delay time of discharge of the discharge voltage at the machining gap. The high-frequency component is compared with a reference value to obtain a first comparison result. The discharge voltage level is compared with a reference level to obtain a second comparison result. The pulse control device controls pulse off time based on the first comparison result and the detected delay time, and cuts off a discharge pulse based on the second comparison result.

Power-supply control device for electrical discharge machining apparatus

A discharge pulse control device cuts off a pulse width of the a discharge pulse being produced in a machining gap when a comparison result of a voltage level comparator indicates abnormal electrical discharge. Upon detection of abnormal electrical discharge based on comparison results of a high-frequency component comparator and the voltage level comparator, a quiescent period control unit constructed from a discharge pulse diagnosis device, a first pulse counter, a second pulse counter, and a quiescent pulse control device performs change setting of the quiescent period at the time of occurrence of abnormal electrical discharge and sends that information to the discharge pulse control device. Subsequently, the discharge pulse control device performs change control of the quiescent period at the time of occurrence of abnormal electrical discharge so that the discharge pulse and the quiescent time are optimally controlled.

Power source controller of electrical discharge machine

A power-supply control device includes a high-frequency component detecting unit, a machining voltage level detecting device, and a pulse control device. The high-frequency component detecting unit detects a high-frequency component of discharge voltage at a machining gap. The machining voltage level detecting device detects a discharge voltage level at the machining gap. The high-frequency component is compared with a reference high-frequency component to obtain a first comparison result. The discharge voltage level is compared with a reference voltage level to obtain a second comparison result. The pulse control device controls pulse off time based on the first comparison result, and cuts off a discharge pulse based on the second comparison result.

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Tokyo, Japan

Kazunari Morita