1. The running characteristic of medium wire WEDM is that the molybdenum wire reverses back and forth to carry out cyclic processing. There are many reasons that affect the surface roughness of the workpiece, among which the reversing of molybdenum wire is one of the reasons. At the moment of commutation, the tension of molybdenum wire will become uneven, which will cause slight vibration of molybdenum wire, which will reduce the surface roughness of workpiece. Under the same processing conditions, reducing the commutation times of molybdenum wire and increasing the effective length of molybdenum wire can effectively reduce the vibration of molybdenum wire and improve the surface roughness of workpiece.
2. Pulse power processing is an important factor affecting the surface roughness. Generally, high frequency pulse is used in pulse power supply. The surface roughness can be changed by reducing the energy of single pulse. The pulse width and pulse interval can be continuously controlled without interference from other factors. The pulse width, the number of power amplifier tubes and the peak current of power amplifier tube can all affect the energy of single pulse. Reducing the pulse width and peak current can improve the surface finish, but reducing the width will greatly reduce the production efficiency, but it is less affected than the pulse width. Therefore, reducing the peak current, increasing the pulse width and adjusting the pulse interval can not only improve the machining efficiency, but also improve the surface finish.
3. The feed rate can also affect the surface roughness, so the feed rate should be appropriate. Low feed speed will affect the efficiency, high feed rate is easy to break or burn wire. In order to solve this problem, Baoma CNC has developed for many years, which makes the feed speed of Baoma CNC wire cutting machine from slow to fast. When the processing current reaches 75% - 80% of the short-circuit current, the voltmeter pointer on the control board is stable, and the feed rate ratio is more appropriate.
