1.4 Related to wire device and working fluid
(1) When the molybdenum wire breakage is related to the wire device, the root cause is the decline of the molybdenum wire device precision. Especially when the different wire guide wheels are worn out, the jitter of molybdenum wire will increase, which would destroy the normal spark discharge gap of wire cut edm machine and be easy to make large current discharge in concentration. Thereby the chance of molybdenum wire breakage. Here are three aspects that can be checked in the precision of wire guide wheel.
① The V-shaped width of guide wheel increases. This will make the wire cut edm electrodes in the Y-axis direction to produce reciprocating displacement. This phonomenon happens when the performance of wire stocking bottle forward and reverse but there is no feeding or jumping in wire edm machine.
② The V-shaped groove bottom diameter of guide wheel is not round. This is due to the support bearing of guide wheel is damaged. During the processing, the molybdenum wire doesn’t rightly enter the V-shaped groove of guide wheel or some dirty particles get stuck on the guide wheel. So the molybdenum wire pulls out of the deeper groove.
③ The poor contact between conductive shaft and conductive roller leads to the molybdenum wire breakage. In the wire cut process, we found ammeter pointer shakes sharply, wire feeding speed is not uniform, and sometimes ammeter pointer went back to zero, the console feeding speed ran fast and all such things took place. There was no discharge in the wire cut machine, eventually the molybdenum wire broke off. At this time, replace the new conductive wheel and new conductive shaft for wire cut edm machines.
④ As to the large thickness workpieces or those that are required to cut at high cutting speed in electric discharge machining, the working edm fluid ratio may be appropriate to light some of the concentration of about 5% to 8%, so that the processing will be more stable and not easy to be broken.
⑤ The working edm fluid becomes dirty with a long time after the deterioration of the overall performance. This is an important reason to the molybdenum wire breakage. In the actual wire cut machine practice, the working edm fluid can be measured whether it is in deterioration as follows. When the cutting current is around 2A and the wire cutting speed of 40mm2/min, working 8 hours per day and two days usage would be in best condition. If the working edm fluid is continued to use for 8 to 10 days, it can be easy to cause the molybdenum wire to break out. It should be replaced with new working edm fluid.
(2) Some researches point out that working edm fluid with high purity water configuration cuts more stably and less molybdenum wire breakage takes place for cnc machines. It is estimated that high purity water in the ion exchange purification process has been removed some of the harmful ions, such as calcium ions and magnesium ions. Thus in the wire cut machine process, although the electrochemical products involve and various ions are mixed in the working edm fluid, the processing is still stabilized by removing the harmful ions.
1.5 Related to the materials of the workpiece itself
It is generally believed that the metal that has not been forged, quenched, tempered can easily cause the molybdenum wire breakage. The uneven distribution of carbide in the steel will result in the unstable electrical processing performance and cause the arc discharge and molybdenum wire breakage. The steel contains large carbide particles. These particles gather into a group and distributed unevenly. This kind of materials in wire cut machine practice is easy to crack and deform to clamp steel wire, resulting in the edm electrodes wire breakage. Therefore, in order to reduce the wire breakage caused by the workpiece material, it would be better to select the materials with good forging performance and good hardenability for edm equipment. Workpiece materials with small heat treatment deformation will promote the distribution of carbide in the steel evenly, so that the process stability enhances. Take the cold die mould with the main process wire cut edm machine as example, try to use CrWMn, Cr12Mo, GCr15 and other alloy tool steel and to correctly select the thermal processing methods and strict implementation of heat treatment specifications.
In conclusion, to choose a reliable and trustworthy edm electrodes molybdenum wire for wire cut edm machines cost is very important. TAGUTI edm parts molybdenum wire always wins good reputation from customers since 1997. We keep advancing our product portfolio of edm consumables these years and hope to provide the best edm services and good cost performance for global edm machining parts. We always focus on the balance between quality and quantity. From a high perspective for wire cut edm machine, to speed up the development of low speed wire cutting machine, to narrow the gap with the international advanced level, to strengthen the high speed wire cutting machine innovation breakthrough, to take a high speed wire cutting machine and low speed wire cutting machine combination and to develop the more prosperity of China’s EDM wire cutting process.