The reasons that influence surface quality of wire cut edm filters machining: instability of machining process and unclean working solution. Here are some measures to improve this situation:
1. Make sure producing accuracy of wire drum and guides, control the axial and radial jumping of wire drum and guides,the turning of guides should be flexible and smooth, it will reduce vibration of guides to realize stability of machining.
2. Lower wire running speed if necessary, it will get stability of wire running, especially when it change direction.
3. According to characterize of wire cut EDM machining, the high speed running wire change direction frequently, the tension of wire could change rapidly at the moment while changing direction, it will lead to vibration of wire, and affect surface quality accordingly, so it is better to reduce times of changing direction. Proved by experiment, when machining conditions are same, prolong effective length of machining wire and times of changing direction,will reduce vibration of wire to improve machining stability and surface quality.
4. Make sure tight the wire evenly and smooth to avoid different tension of wire at different position, as if tension is variable to different position, the wire is easy to vibrate.
5. The moves of working table in X and Y direction are also very important to machining quality, it is helpful for surface quality if working table feed smoothly and evenly. How to ensure working table move smoothly: first do cutting test,consider direction changing is smooth already,feed in X and Y direction separately,if steps of step motor feed in X and Y direction in positive and negative direction are same, it means the wire tension is even, can make sure working table feed smoothly and evenly.
6. To adjustable wire frame, it is better to reduce the length of frame according to height of workpiece. If span is too big, molybdenum wire will vibrate; if span is too small, cooling solution is not easy to enter workpiece. Take cutting 40mm thick workpiece for instance, span of wire frame could be 50-60mm, distance of up and down nozzles to workpiece could be 6-10mm, this way, molybdenum will have better rigidity, avoid vibration.
7. Workpiece feed speed must be suitable, as during cutting, if feed to fast, it doesn’t have enough time to remove metal chips, this way, it is easy to happen short circuit, make cutting is not stable;of course, if workpiece feed with lower speed, machining efficiency would be lower too.
8. impulse power is also a vital factor to machining surface quality. Impulse power adopts rectangular pulse, as the frequency width and interval is adjustable continuously, not easy to be disturbed. Reduce the power of single pulse can improve surface quality. frequency width, number of power amplifier tube, and peak of amplifier are three main factors to the power of a single pulse. So reduce frequency width and peak electric current can increase surface quality, but reduce frequency width will reduce machining efficiency. Normally, reduce peak electric current to get better surface quality.
9. Keep stable power voltage, if power voltage is not sable, will make voltage between workpiece and molybdenum wire is not stable, and make electric discharging is not stable, bad for surface quality.
10. Keep working solution clean, after long time use, metal chip will pollute working solution, the polluted working solution will block cooling system, so it is better to change liquid after long time use. wire cut edm filters
