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: 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 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: A method of manufacturing a composite material by melt-spraying, comprising the steps of melt-spraying a metal as the main constituent of the composite material onto a base plate and injecting a reinforcing substance comprising discontinuous fibers into the metal melt spray stream upstream of the base plate to effect mixing of the reinforcing substance in the melt-sprayed stream of metal within a temperature range without producing a resultant reaction layer between said metal and said reinforcing substance.

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.