Wire EDM: Key Physical Properties

by | Mar 9, 2021 | Elements of EDM, Wire

Key physical properties that electrical discharge machine wires must incorporate are:

  1. Conductivity: A high and good conductivity rating is imperative in light of the fact that, at any rate hypothetically, it implies wire may convey additional current, that compares to a hotter spark and improved cutting rate.
  2. Tensile strength: This shows the capacity of wire to endure wire strain and tension, forced at wire amid cutting, keeping in mind and goal to make a vertically straight cut.
  3. Elongation: Which portrays in what way wire “gives” or gets physically deformed before breaking.
  4. Melting Point: The point in time when the wire electrode is impervious to be melted too rapidly buy electric sparks.
  5. Memory: This property may favor the wire to remain straight.
  6. Flush Ability: The better the flush ability or (flush-capacity), the quicker wire will cut, and the possibility of wear breakage will diminish.
  7. Cleanliness: The wire can be filthy, because of pollution through residual metal powder available from the drawing procedure, paraffine or drawing lubricant is added to the wire by a few wire manufactures proceeding spooling.  

Common Wire Materials

Zinc Coated: Zinc is mixed into the surface of the wire. Increased zinc level of the wire electrode will improve cutting speed of the WEDM. Also, the zinc-coated wire will experience a secondary heat treatment procedure in an oxygen environment. This creates a very thin layer of oxide on the zinc surface, thus enabling the wire to slide through the wire guide and stops gentler zinc from chipping. This kind of coated wire offers the largest amount of efficiency by increased cutting speed.

 Solid Brass: Zinc + copper = brass. Brass wire is manufactured in many different tensile strengths and varying degrees of hardness. These properties are dependent upon the use and material that is being machined.

Coated Copper: This incorporates a core wire enduring moderately higher thermal conductivity with a shallow coating layer framed by a low-boiling point material.  Coated wires change the wire electrode using an alloy or metal bearing low vaporization temperature for example, zinc, lead, antimony, cadmium, bismuth, tin, and other alloys. This secures the center of the wire contrary to thermal shock, ensuring the rate of electrical discharge, which allows increments of frequency of electrical discharge decreasing the risk of wire breakage.

Coated Steel Wire: For accomplishing great rigidity and strength, steel wires are coated with zinc, lead, antimony, cadmium, bismuth, tin, and other alloys. For better electrical discharge machining, wire electrodes need to consume a high electrical conductance. this empowers a higher machining current over the wire electrode, and it needs to possess higher mechanical strength for increased force in the machining zone. Diffusion Annealed Wire: This process is aimed at improving execution speed. Zinc has a lower melting point and of the aforementioned wires diffusion wire has a higher volume of zinc coating resulting in higher melting points. This drove the advancement of diffusion in coated wires, where the encased wire is strengthened at such temperature until the point that the alloy stretches out from the outer surface to the core, enhancing mechanical quality of the wire electrode and creating a heat shield from spark impact and short circuits.

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