Molybdenum wire cutting

Technological advantages

Using molybdenum wire cutting machines offers much more advantages than disadvantages. When you can accept the few limitations of moly wire cutting and your workpieces are within the tolerances reachable of our machines, then our Noviform-M series offers you an economical very interesting high functional tool able to make high quality parts and save tremendous money in production cost.

This molybdenum wire is mostly used in the fixed diameter of 0.18mm(+- 0.003mm) to meet blueprint requirements of narrow kerfs and near-sharp, inside corner radii. This 0.18mm gives a perfect balance between lifetime, cutting speed, cutting tolerances and surface quality.  Because of it’s high tensile strength, moly wire aids in maintaining excellent wall straightness and reducing the number of wire-breaks common with many copper or brass wires. In special cases, typically in medical and military applications, there can be no copper or zinc contamination of the wire cut surface. These criteria eliminate all copper-family wires and forces the use of a moly or tungsten wire.

Contradictious to copper (tensile strength 200-250N/mm²) or brass wires (soft brass 375 N/mm² and hard brass 1180 N/mm2), molybdenum wire is a very high strength wire (tensile strength 1724 N/mm2) Molybdenum wire resist to very high pulling forces and breaking it is very difficult. This gives a triple advantage:

  • much less wire breakage due to much higher pulling resistance
  • Almost no elongation (<2%) of the wire during cutting
  • Higher pulling force guarantees also straighter cuts in the sense that the wire resists much better to side-forces and is less bending or get less deviated in corner movements. This allows it to cut very fine, very straight-walled details with sharp definition. The harder pulled, the straighter the wire stays during cutting.
  • Due to the higher pulling forces possible, we can increase the move through speeds of the cutting wire remarkable and can make a much faster cutting (our machines have standard 4 wire feed speeds) .

Because moly wire has very high melting temperature, (2,625°C), compared to copper (1085°C) and brass (900-940°C), the molybdenum wire EDM cutting machine can handle very high working temperatures. As result of this high temperature resistance almost all conductive materials, most difficult, hardest and toughest, can be cut with our Novicut-M. Most of the materials are melting much faster than molybdenum and even normal steels can be cut faster as we handle more electric spark power per second and per mm wire than normal wire. By using patented zirconium guide wheels, we could increase drastically the cutting current and also the cutting speed.

One disadvantage of this high temperature resistance is that the spark craters made in the wire are much smaller than the ones made in the workpiece. As results the burned away carbonized particles between wire and workpiece are more difficult pulled out of the cutting area by the smaller craters in the wire. For this Novick developed a drum with 4 speeds, so that the moly wire can move through the metal with a much higher speed and takes much more carbonized particle with him. Good Flushing with a slightly longer retract time is here the solution.

The EDM spark craters left on the wire’s surface are very small compared to those left on the workpiece that is cut. So, the wire is almost not damaged after passing through the material and this results in a much longer of reuse the wire. Lifetime of the molybdenum wire can reach sometimes weeks. On the other side the sparking result on the workpiece are much bigger and gives a better and faster cutting results. The removable rate can be very high if the flushing is under control.