Reciprocating wire feeding type wire cut electrical discharge machining machine tool electrode wire control method

Abstract

The invention discloses a reciprocating wire feeding type wire cut electrical discharge machining machine tool electrode wire control method. The control method comprises the following steps: multiple times of reciprocating wire feeding and adjustable wire feeding between every adjacent two times of reciprocating wire feeding are performed; each time of reciprocating wire feeding: two reversing switches and programmable controllers are used for controlling servo motors to drive wire storage cylinders to repeatedly rotate forwards and reversely by multiple times, and meanwhile, angle encoders are used for detecting rotating angles of the wire storage cylinders and returning to the programmable controllers, so that the wire storage cylinders rotate forwards and reversely by preset angles to realize multiple times of circular reciprocating wire feeding of electrode wires with preset lengths; and each time of adjustable wire feeding: after the previous time of reciprocating wire feeding is finished, the programmable controllers are used for controlling the servo motors to drive the wire storage cylinders to forwards rotate by preset angles to perform the forward adjustable wire feeding by a period of distance, and the sum of the distance of the forward adjustable wire feeding and the distance of the following reciprocating wire feeding is smaller than the distance of the adjustable wire feeding and the previous reciprocating wire feeding. The control method can prevent electrode wires from being broken due to loss, prevents frequent replacement of the electrode wires, guarantees normal operation of machine tools, and is high in automation degree.

Description

technical field [0001] The invention relates to a control method for an electrode wire of a reciprocating wire electric discharge wire cutting machine tool. Background technique [0002] In view of the processing characteristics of the reciprocating wire EDM machine tool, in order to ensure that the wire electrode can realize reciprocating running electric discharge machining, two reversing switches are set when the wire storage cylinder moves, that is, when the wire storage cylinder runs to one side (forward direction) ) When the travel limit is reached, touch the reversing switch on this side (positive direction), and the wire drum motor will change the running direction (forward and reverse), and drive the wire storage drum to move to the other side (negative side). On the other side (negative side) reversing switch, the wire drum motor changes the running direction (reverse to forward rotation) and runs to the positive side. Repeated movement in this way realizes recipro...

AI Technical Summary

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 corroded 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 until normal processing cannot be performed.

In order to ensure that the electric erosion degree of the wire electrode is relatively small, the wire speed of the reciprocating wire is relatively high (8-15m / s). 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 blown directly. In order to avoid this situation, the system simultaneously sends high-frequency pulse The power output is turned off. At this time, the feed processing of the machine stops until the reversing delay is completed and then resumes processing. Therefore, there must be a buffer section on both sides of the electrode wire wound on the wire storage cylinder that does not participate in EDM. In theory, this area In addition to very small friction loss, the diameter of the section electrode wire has almost no loss, which brings about a problem. With the increase of processing time, the electrode wire participating in the processing section is getting thinner, so the slit formed by the processed workpiece is also It 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. The buffer section of the wire is difficult to enter the previous slit, which may easily cause the electrode wire to be stuck in the buffer area, requiring frequent shutdowns and replacement of the electrode wire, which affects the normal operation of the machine tool

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