Abstract: An EDM machine with a plurality of separate electrodes selectively driven by the same actuator on the same head of the EDM machine is provided. Preferably, all of the electrodes are not used to cut the workpiece at the same time. Rather, the actuator has a drive mechanism, which is preferably servo-controlled, and each electrode is selectively engaged with the drive mechanism to advance and retract only the desired electrode relative to the workpiece. Either the workpiece or the EDM head is preferably manipulated using a CNC positioning system to accurately locate the desired electrode relative to the workpiece.

Abstract: Non-contact machining of workpieces on a mass production basis is accomplished with dynamic and adaptive feedback control to achieve accurate machining of a first and second feature to a specified combined size. The first feature is machined in the workpiece and measured to obtain a value which represents the size. A proces parameter is adjusted in accordance with the measurement value based on a stored transfer function so that the second feature will be machined with an extrapolated size such that the combined size will be within the acceptability limit. Additionally, the combined measurement values of successive workpieces is analyzed to determine the trend of change of the values with respect to the specified size and the parameter is adjusted to machine the first feature and the combined features more accurately.

Abstract: Structure for and method of electrical discharge machining with a wire electrode to produce small holes including completely controlling electrical discharge machining parameters such as voltage, reactance, current and servo speed with a programmable microprocessor, central processing unit sensing first sparking between the wire electrode and the workpiece and controlling depth of cut from the position of the electrode on spark initiation electrode feeding to replenish eroded electrode through clamping sequencing between an electrical discharge machine head and an electrode carrying slide thereon. In accordance with the invention there is also provided ultrasonic vibration of at least one of the workpiece, a wire electrode guide and the electrode during machining.

Abstract: A wire guide for a servo driven wire electrode in an electrical discharge machine (EDM) has inserts defining a precision guide slot for the electrode. The inserts are coated with a low friction coating to smooth the servo drive of the wire electrode through the wire guide so as to improve spark gap erosion produced between a tip portion of the electrode and a workpiece.

Abstract: A method for welding galvanized material including a low vapor pressure mild steel core and a high vapor pressure rich zinc coating includes the steps of arranging components of such galvanized material in juxtaposed relationship at a lapped joint; and applying a high density laser energy beam along the lapped joint as a weave pattern in which the weave pattern has a width great enough to bridge the lapped joint and a weave pattern frequency which forms a predetermined weld pool between the components and wherein the lapped joint and weave pattern combine to define a vapor pressure relief path so that the weld pool will not be disrupted during the application of the high density laser energy beam to the galvanized components.

Abstract: A glass ceramic reflector having a uniform material composition which has an almost 100% reflectivity that is diffusive in the reflectance range of the entire solar spectrum from 450 to 900 nm wavelength. Furthermore, the ceramic material has a high absorption of ultraviolet wave lengths and low reflectivity in the infrared region to minimize thermal loading of the laser rod of high gain laser material. In one preferred embodiment, the glass ceramic reflector is mica based and has a composition of approximately 55% crystal and 45% residual glass, thereby defining a microstructure that enables the ceramic material to be machined to form an interior surface configuration that is easily closely coupled to flashlamp and laser rod components of the laser device.

Abstract: A process for drilling chamfered holes includes the steps of directing noncontact energy onto the outer surface of the part to form a recessed crater-like entrance with chamfered walls and thereafter directing a small diameter wire electrode adjacent the substrate and spark eroding the base without removing material from the chamfered walls so as to produce a combined passage through the part with a chamfered entrance leading to a smaller outlet. In one embodiment the part has a ceramic coating which is initially removed from the part by either focusing a laser beam to a penetration depth which removes the ceramic coating while forming the entrance and in another embodiment the coating is initially removed by imposing a high voltage pulse thereagainst from a spark erosion electrode of electrical discharge machining equipment.

Abstract: An electrical discharge machine with automatically replaceable electrodes. The machine includes an electrode holder with a clamp operable to alternately receive and release an electrode, an electrode cartridge containing a plurality of stacked electrodes and a shuttle movable toward and away from the electrode holder. When the shuttle is moved toward the electrode holder, it removes an electrode from the cartridge and moves it into alignment with the electrode holder.

Abstract: EDM apparatus has a servo drive under the control of a main control system for advancing a machining electrode toward a conductive workpiece. When the electrode arrives at a surface of the workpiece to commence EDM machining, the main control system causes a sudden deceleration of the servo. The depth controller detects this sudden deceleration by means of a sensor and sets a zero reference plane from which machining depth is measured. The depth controller can also detect electrode breakthrough by detecting servo acceleration occurring when the electrode breaks through a surface of the workpiece.

Abstract: An electronic depth controller is associated with EDM apparatus for controlling the depth of holes which are machined in workpieces by the EDM apparatus. The electronic depth controller comprises its own microprocessor which acts upon selectable input data from a control panel to provide signals relating to hole depth control to the main control system of the EDM apparatus. The electronic depth controller is selectively operable to one or the other or both of two operating modes. Data relating to each mode is input to the system via switches on the control panel.

Abstract: A process control system for electrical discharge machining apparatus to control automatically the machining of a workpiece. The process control system is operable to receive and retain a plurality of operation instructions regarding electrical discharge machining parameters and transmit operation commands to the electrical discharge machining apparatus to execute the operation instructions in controlling the complete machining of a workpiece. The process control means includes a storage unit operable to store a plurality of operation instructions enabling absolute repeatability of the machining process defined by the operation instructions in the storage unit for a plurality of workpieces. The process control system also includes a digitally controlled servo system to regulate the movement of the electrode toward and away from the workpiece.

Abstract: A steady rest follower for a workpiece comprising a frame supporting a slide which is movable in directions toward and away from the workpiece. A pair of vertically spaced support wheels are mounted on the slide for engagement with the workpiece. A pair of springs yieldably urge the slide rearwardly away from the workpiece and into engagement with the peripheral surface of an eccentrically configured roller member that is mounted on the frame. During the machining of the workpiece, the eccentric roller member is rotated to move the slide against the pressure of the springs toward the workpiece so that the support roller members are maintained in continuous engagement with the workpiece as the size of the workpiece is reduced.

Abstract: Electrical discharge machining apparatus in which a plurality of generally parallel electrodes are moved during machining and during refeed in generally parallel paths. A drive roller assembly is provided for refeeding the electrodes after each machining cycle to compensate for erosion of the electrodes that occurred during the preceding machining cycle. The drive roller assembly consists of a plurality of rollers arranged on opposite sides of the electrodes so that the electrodes are drivingly engaged between the rollers. The apparatus is further equipped with a movable gage member having an electrode engaging surface. After each machining cycle, the gage member is moved to a predetermined position between the location of the workpiece and the electrodes. The electrodes are refed into engagement with the electrode engaging surface which defines a reference surface between the workpiece and the electrodes. Refeed of the electrodes is terminated when the electrodes engage the gage member.

Abstract: Electrical discharge machining apparatus in which a plurality of generally parallel electrodes are moved during machining and during refeed in generally parallel paths. A drive roller assembly is provided for refeeding the electrodes after each machining cycle to compensate for erosion of the electrodes that occurred during the preceding machining cycle. The drive roller assembly consists of a plurality of rollers arranged on opposite sides of the electrodes so that the electrodes are drivingly engaged between the rollers. In one embodiment of the invention, the rollers slip on the electrodes after the electrodes have been moved to positions engaging the work until all of the electrodes have been moved into engagement with the work. In another embodiment of the invention, each electrode is independently driven and engagement of each electrode with the work is electrically sensed and in response to such sensing, the drive for that electrode is discontinued.

Abstract: Electrical discharge machining apparatus having means to sense the position of the electrode at the start of EDM machining of a workpiece. The apparatus includes means to measure the forward movement of the electrode during each machining cycle and regulate the backward retracting movement of the electrode to a preselected distance so as to compensate for erosion of the electrode during the machining cycle to thereby facilitate positioning of the electrode in the correct location for the next machining cycle. The apparatus includes a sensing device operable to transmit electrical pulses corresponding to incremental movements of the electrode and control circuitry which receives the pulses and controls subsequent movement of the electrode.