Workpieces: For workpieces with poor forging performance, hardenability, and large thermal deformation, if the forging and quenching parts are not subjected to tempering treatment and are directly cut by wire cutting, some workpieces may crack and break the molybdenum wire during the processing of the wire cutting machine; Some may cause deformation in the gap, causing the molybdenum wire to be clamped or snapped. In addition, the impure material of the workpiece, high internal stress, and poor clamping of the workpiece are highly likely to cause wire breakage.
Working fluid: Blackening of the working fluid or excessive concentration or dirt during processing can easily cause wire breakage (especially when cutting extremely thick workpieces).
Electrical parameters: Improper selection of electrical parameters is also an important reason for wire breakage. Therefore, it is necessary to choose reasonable electrical parameters based on the thickness of the workpiece, widen the pulse interval, which is conducive to the discharge of molten metal particles. At the same time, peak current and no-load voltage should not be too high, otherwise it will increase the size of a single pulse, accelerate the cutting speed, and easily cause concentrated discharge and arc pulling, leading to wire breakage. Choose the appropriate discharge gap based on the thickness of the workpiece, and the discharge gap should not be too small. Otherwise, wire cutting in the middle of the wire is prone to short circuits, which is not conducive to cooling and the removal of corrosive substances. Excessive discharge gap will affect surface roughness and processing speed.
Pulse power supply: When the machining current is high and the spark discharge is abnormal, the output of the pulse power supply has changed to DC output. If the output current exceeds the limit, the spark discharge suddenly turns into a blue arc discharge during the machining process. Burn points appear on the molybdenum wire, which concentrates the discharge on the molybdenum wire and generates a large amount of heat.
Workbench movement: The cutting accuracy of the workpiece is ensured by the lead screw, and the gap between the lead screw and the nut of the wire feeding machine tool is controlled by the spring. If the lubrication of the screw is poor or the spring force is insufficient, it can cause the workbench to crawl and move. In this case of cutting, the high-frequency current of the wire cutting machine will cause frequent short circuits. If the fault is not eliminated in time, it will inevitably cause wire breakage in the wire cutting process.
