The cutting smoothness of fast-moving wire is composed of two factors. One is the size of pits removed by single discharge. Its RZ is usually between 0.05 and 1.5 mu, which is not necessary for the cutting smoothness. The other is the convex and concave stripes formed by reversal. Its RZ is usually between 1U and 50u. It may be larger than 0.1MM, which is the most important factor of the line cut smoothness. At the same time, it is accompanied by the black and white stripes of reversal, giving people a very intense visual impact.
It is easy to control the pit size due to single discharge, which only needs to decrease the energy of a single pulse. Only a single pulse energy is small enough to form a thick workpiece without cutting, or even a short circuit without discharging spark state. This is similar to the fine regulation in EDM, forming a very low power, chip removal can be very poor unstable processing. Moreover, because the RZ formed by the discharge pit is not in the same order of magnitude as the RZ formed by the commutation fringe, it is important to control the RZ along with the commutation fringe. The accuracy of guide wheel and bearing and the constant tension between the upper and lower wires cause the inconsistency of the moving track between the upper and lower wires. This mechanical factor is the main reason for the formation of convex and concave reversing.
In order to improve the cutting finish of fast-moving wire, the following methods can be adopted to improve it:
1. Guide wheels and bearings adhere to good accuracy and stability of operation, reduce silk shaking and jump, and minimize the silk track to adhere to one-line displacement.
2. Silk should not be too tight, water should not be too fresh, fresh water will certainly benefit the cutting power, but the cutting finish is not superior to fresh water zui.
3. Maintain the appropriate tension of the wire, and adjust the guide wheel and the input block so that the tension of the working area remains unchanged when the wire goes up and down.
4. Decrease the pulse width and peak current appropriately, that is to say, reduce the pit size.
5. A splint is added on the upper and lower sides of the over-thin workpiece, so that the commutation stripes are buffered within the scope of the splint.
6. XY motion is stable, accurate, good follow-up fidelity, non-blocking crawling is also extremely important.
7. Insist on stable and loose frequency conversion tracking.
8. Thicker workpiece can use short filament properly. The feed of one commutation is less than half the diameter of the filament, which also conceals the commutation fringes. Of course, it's just a cover-up.
9. Re-cutting or repeated cutting with appropriate reserve will have beneficial effect on scale accuracy and smoothness if the cutting amount is very small. Three times of continuous sweeping will remove the reversing fringes fundamentally. As long as the machine tool repeats the positioning accuracy and the appropriate reserve is processed repeatedly, the smoothness of the cutting surface will be improved by one or two orders of magnitude, and the effect and slow walking will be achieved. Silk is similar and time-consuming, which is one of the strengths of fast-walking wire cutting machine. |