Control device for electric discharge wire cutting machine tool electrode wire and wire feeding method

Abstract

The invention discloses a control device for an electric discharge wire cutting machine tool electrode wire. The control device comprises a rack, a wire storage barrel, a plurality of transition guidewheels, an upper guide wheel, a lower guide wheel, an electrode wire, a tension adjusting device and the like; an angle coder is additionally arranged on the end part of a transmission screw end; axial tension sensors are arranged on parts ,between an upper machine head and a wire storage barrel as well as between a lower machine head and the wire storage barrel, of the rack; each axial tension sensor is provided with a tension detection wheel through a bearing; the invention further discloses a wire feeding method; by adopting the control device and the wire feeding method, the machining precision can be greatly improved; the wire feeding machining section and buffering section of the electrode wire can be adjusted dynamically and timely when the electrode wire is jammed; the phenomenonthat the electrode wire is jammed and broken because of loss is avoided; the electrode wire does not need to be changed frequently; normal operation of the machine tool is ensured; and machining efficiency and the utilization rate of the electrode wire are enhanced.

Description

technical field [0001] The invention relates to a control device and a wire-feeding method for an electrode wire of a reciprocating wire-feeding wire electric discharge machine tool. Background technique [0002] When the reciprocating wire EDM machine tool is processing, the motor is driven by the control element, and the wire storage cylinder is driven to rotate forward and reverse alternately, so that the electrode wire is retracted and retracted to realize reciprocating operation processing. During WEDM, a high-frequency pulse voltage is applied between the electrode wire and the workpiece, and the workpiece is driven to move according to the programmed trajectory through the workbench. A micro-gap discharge is formed between the electrode wire and the workpiece, so that the workpiece is formed by electric erosion. At the same time, the electrode wire will also be eroded to a certain extent, and there is friction loss in the wire transport system. Therefore, as the proce...

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Problems solved by technology

During WEDM, a high-frequency pulse voltage is applied between the electrode wire and the workpiece, and the workpiece is driven to move according to the programmed trajectory through the workbench. A micro-gap discharge is formed between the electrode wire and the workpiece, so that the workpiece is formed by electric erosion. At the same time, the electrode wire will also be eroded to a certain extent, and there is friction loss in the wire transport system. Therefore, as the processing time increases, the diameter of the electrode wire will become smaller and smaller. The change in diameter will lead to poor processing consistency and affect processing accuracy. , especially in demanding finishing machining; and the rigidity of the electrode wire is poor, and the side adjacent to the workpiece is resisted during machining, which inevitably bends and forms an arc. The waist drum shape also affects the processing accuracy; at the same time, in order to ensure that the electric corrosion degree of the electrode wire is relatively small, the reciprocating electrode wire speed is high (8-15m / s). There is a deceleration-commutation-re-speed-up process. If a high-frequency voltage is applied between the electrode wire and the workpiece during this process, the electrode wire is likely to be directly blown. To avoid this situation, when the wire storage cylinder is reversing At the same time, the system turns off the output of the high-frequency pulse power supply. At this time, the feed processing of the machine stops until the reversing delay is completed and then resumes processing. Therefore, the electrode wire wound on the wire storage drum must have a wire-feeding processing section and a wire processing section at both ends. For the buffer section that does not participate in EDM, theoretically, the diameter of the electrode wire in the buffer section has almost no loss except for a very small friction loss, which brings about a problem. Thinner, so the grooving formed by the processed workpiece will become smaller and smaller, and the width of the cutting gap is equal to the diameter of the electrode wire in the discharge section plus 0.02mm discharge gap, and the diameter of the electrode wire in the discharge section after loss plus 0.02mm discharge gap When the diameter of the electrode wire is smaller than that of the buffer section, it is difficult for the buffer section of the electrode wire to enter the previous cutting groove, causing jamming, which may easily cause the electrode wire to be stuck in the buffer section, requiring frequent shutdowns and replacement of the electrode wire, which affects the normal operation of the machine tool

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