Abstract: While switching polarity of an electrode, a voltage is applied between the electrode and a workpiece hard metal with the electrode used as a negative-electrode such that tungsten carbide (WC; component of the hard metal) is anodized to form a tungsten oxide (WO3), and a voltage is supplied therebetween with the electrode used as a positive-electrode such that cobalt (Co) that is a component of the workpiece is electrolytically-eluted and at the same time the WO3 generated by anodization is dissolved in the machining fluid, a saline solution (NaCl) or an aqueous solution of nitrate of soda (Na(No3)) is used as an machining fluid; a calcium salt is added beforehand to the machining fluid to react tungstate soda (Na2WO4) generated in the machining with the calcium salt whereby calcium tungstate (CaWO4) is produced; and a calcium compound is separated and recovered using a difference in specific gravity.

Abstract: An electric discharge machining apparatus for supplying machining electric power to a gap between an electrode (1) and a workpiece (2). The apparatus includes a gap dimension detection device (8) for detecting a dimension of the gap, a gap average voltage detection device (11) for detecting an average voltage of the gap, a gap dimension correction device (13) for correcting the dimension of the gap, and a gap dimension correction starting device (12) for starting the gap dimension correction device (13) when a first comparison between a detected gap dimension and a predetermined allowable value and a second comparison between a detected gap average voltage and a predetermined reference average voltage are made and the gap dimension detected by the first comparison is larger than the predetermined allowable value and the gap average voltage detected by the second comparison is smaller than the predetermined reference average voltage.

Abstract: A surface treating is performed by an electric discharge. The electric discharge is generated by applying a voltage between an electrode and a metal workpiece. The electrode is a solid or green compact electrode or the like which is made of a reforming material. The workpiece may be an end mill or the like. Then, a coating layer is formed on a surface of the metal workpiece. Thereafter, a nitriding treatment is performed on the coating layer in a nitriding vessel or the like. Thus, a hard coating layer of better quality is formed on the surface of the workpiece whether a material of the workpiece is steel or hard metal.

Abstract: A surface treating method uses an electric discharge machining to form a coating layer having strong adhesion and excellent characteristics on a metal surface such as a hard metal. A discharge electrode is formed by powders containing metal hydride. Electric discharge is generated in a working fluid containing carbon between the discharge electrode and a workpiece. Thus, a coating layer of the metal hydride is formed on a surface of the workpiece.

Abstract: A surface treating apparatus rotates a rotating tool and moves a surface treating electrode relative to the tool via a rotating shaft driver and a Z-axis driver. A power source applies voltage to generate an electric discharge between the tool and the electrode, thereby forming a reforming layer on a peripheral flank and a rake face of the tool.

Abstract: An apparatus and process for forming surface layers on electrodes by electron discharge machining. A machining gap, between an electrode and a workpiece is filled with a dielectric mixture containing metallic or submetallic powder. The apparatus uses a swinging mechanism to move the electrode during processing. The apparatus uses a high-voltage superposition circuit to superpose a voltage of 100-400 V across the gap. The apparatus uses a current limiting resistor of 100-300 .OMEGA. to ensure that the main circuit supplies a low voltage of approximately 100 V to the machining gap. In a second embodiment, the apparatus prevents electrode cracking by dispersing the discharges throughout, and widening, the machining gap.

Abstract: An apparatus and process for forming surface layers on electrodes by electric discharge machining. A machining gap, between an electrode and a workpiece is filled with a dielectric mixture containing metallic or submetallic powder. The apparatus uses a swinging mechanism to move the electrode during processing. The apparatus uses a high-voltage superposition circuit to superpose a voltage of 100-400 V across the gap. The apparatus uses a current limiting resistor of 100-300.OMEGA. to ensure that the main circuit supplies a low voltage of approximately 100 V to the machining gap. In a second embodiment, the apparatus prevents electrode cracking by dispersing the discharges throughout, and widening, the machining gap.

Abstract: A surface treatment method and apparatus therefor for providing wear and corrosion resistance, which includes relatively rotating a modified metallic member to be surface modified and a block, which may be metal only or may include a modifying material (e.g., ceramic or W-C/Co), and generating electrical discharge between the block and the modified metallic member to form a modification layer on the surface of said modified metallic member. If the modifying material is not in the block, it can be supplied via a dielectric bath or spray at the discharge interface. In this manner, the cutting edges of a cutting tool with a complicated shape can be surface modified easily to carry out tool surface treatment which increases a cutting tool life greatly. Cutting and surface treatment can be performed alternately as determined by a controller.

Abstract: An apparatus for forming surface layers on electrodes by electric discharge machining. A machining gap, between an electrode and a workpiece is filled with a dielectric mixture containing metallic or submetallic powder. The apparatus uses a swinging mechanism to move the electrode during processing. The apparatus uses a high-voltage superposition circuit to superpose a voltage of 100-400 V across the gap. The apparatus uses a current limiting resistor of 100-300.OMEGA. to ensure that the main circuit supplies a low voltage of approximately 100 V to the machining gap. In a second embodiment, the apparatus prevents electrode cracking by dispersing the discharges throughout, and widening, the machining gap.

Abstract: A fitting of a first member into a second member is performed until an insertion depth becomes a predetermined value while applying ultrasonic vibration continuously to either or both of the members and, thereafter, the application of ultrasonic vibration is made intermittent.

Abstract: A method and apparatus for electric discharge machining whereby the total machining time to machine a workpiece through coarse, medium and finish surface roughness stages is significantly reduced. Machining condition data for the three surface roughness stages is stored in a memory. As the machining progresses, the surface roughness of the workpiece is monitored. If the surface roughness is found to exceed the reference level for the corresponding stage, machining using the present conditions is continued, whereas, if the surface roughness is below the reference level, the machining conditions are switched to those of the next stage.

Abstract: An ultrasonic machining method comprises the steps of causing a machining solution to readily produce a gas in the machining solution, supplying the machining solution around a workpiece to be machined, and producing an ultrasonic vibration to carry out an ultrasonic machining operation, wherein the gas is produced during the machining operation so that a machined surface of the workpiece is prevented from being degraded by the occurrence of cavitation. An ultrasonic machining apparatus comprise a heater for heating the machining solution or a DC power source for electrolyzing the machining solution.

Abstract: An electrode for precision electric discharge machining having an improved machining rate and surface smoothness with respect to conventional graphite and copper electrodes. The electrode is formed by silicon or other materials which has the same characteristics as silicon, a base of a low melting point metal or an alloy of such a low melting point metal is covered with a layer composed of a mixture of the metal and a high resistivity inorganic compound. The outer layer may be formed by adhesion or by thermal spraying or by a powder metal sintering technique.

Abstract: A method for forming a surface layer on a base material to be processed by electric discharge process, said method being characterized in that the electric discharge process is conducted in liquid or liquefied gas by use of a metalloid or a metal as an electrode for electric discharge process to thereby form on the surface of said base material a layer having an amorphous alloy structure or a very fine crystal structure.

Abstract: A rotation control apparatus for a differential actuator includes two induction motors and a differential mechanism for producing a constant torque on its output shaft based on the differential speed of the induction motors. The appartus includes two inverters each located between one of the induction motors and a common power source for the induction motors and having individual voltage/frequency output characteristics. The inverters set separately the voltage/frequency output characteristics of power supplied to the induction motors so as to control the speed of the induction motors separately, thereby controlling the output torque on the output shaft of the differential actuator. And the output shaft of the differential actuator is controlled to constant speeds regardless of the load torque on the shaft based on the difference of setting frequencies on both inverters.

Abstract: In a wire electrode discharge machining method the breaking of the wire electrode is positively detected by detecting a discharge signal between the wire electrode and the workpiece over a predetermined unit period of time, and then monitoring the average value of high frequency components included in the spectrum of the discharge signal which are independent of the vibration of the wire electrode. When the average value of the high frequency components is found to exceed a predetermined level, countermeasures are taken to avoid the breaking of the wire electrode.

Abstract: A differential actuator including a pair of unit actuators enclosed in a housing is provided. Rotational shafts of the unit actuators support bevel gears in opposed relation to each other. These bevel gears constitute a differential mechanism conjointly with two differential gears which are interconnected rotatably. Rotation of the differential gears around the axis of the bevel gears is taken out to the exterior as an output of the actuator.

Abstract: A method and apparatus for shaping a workpiece by electrical discharge, the workpiece being shaped by a shaping electrode by intermittently impressing a voltage pulse across a working gap formed between the workpiece and the shaping electrode. The apparatus comprises a means for efficiently controlling the duration of a discharge across the working gap according to a condition dependent upon a no-load voltage impressing period, i.e., the period of operation beginning with the impression of the voltage pulse and ending with the occurrence of a discharge, and further according to the state of the working gap detected in terms of a processing voltage mean value. When a no-load voltage impressing period is inside a given interval, the duration of a discharge is increased according to the length of the period. Alternatively, when the no-load voltage impressing period is outside the given interval, the duration of a discharge corresponding to the state of the working gap is not increased.

Abstract: A process and apparatus for the electrical discharge shaping of a workpiece to a shape corresponding to an electrode shape by sequentially applying an intermittent pulse voltage across the working gap between the workpiece and the electrode and wherein a pulse current having a special slant line waveform, e.g. a triangular waveform, which is different from a rectangular waveform is passed across the working gap from the initiation of discharge so as to minimize the electrode consumption ratio.

Abstract: A process for shaping a workpiece using an electrical discharge and an apparatus for practicing the process is disclosed. According to the process, a workpiece is shaped by intermittently impressing a voltage pulse across a working gap between the workpiece and an appropriately shaped electrode. The process includes the step of controlling the duration of the electrical discharge in the working gap in accordance with operating conditions in the working gap to control the average current flow. The apparatus includes a control circuit having a capacitor circuit which controls the duration of the current discharge depending directly upon the time during which the no-load voltage exists in the working gap.