Saturday 15 December 2018

TYPES OF EDM PROCESS Surface finish achievable with EDM




    It is an advanced machining process primarily used for hard and difficult metals which are difficult to machine with the traditional techniques. Only electrically conducting materials are machined by this process. The EDM process is best suited for making intricate cavities and contours which would be difficult to produce with normal machines like grinders, end-mills or other cutting tools. Metals such as hardened tool-steels, carbides, titanium, inconel and kovar are easily machined through EDM

  • Surface finish achievable with EDM




ra value  1.2µm     0.8µm    0.6µm     0.4µm    0.2µm   

 found that Ra value is reduced by increasing the number of cutting passes




  • Die Sinker or “Ram” EDM.
      


          Ram electrical discharge machining (EDM)—also known as conventional EDMsinker EDMdie sinker, vertical EDM, and plunge EDM, is generally used to produce blind cavities. See various machines in . When a blind cavity is required, a formed electrode is machined to the desired shape.








  • Wire or “Cheese Cutter” EDM.


using EDM Wire Cut, the machine features, process ... The wire is passed through the part much like a cheese cutter through cheese. The wire .
















  • Hole Drilling or “Hole Popper” EDM.



For some difficult drilling applications, like carbide, a starter hole can be drilled with small hole EDM and then machined with wire EDM. Small hole EDMing is also used for holes that cannot be deburred due to obstructions. Due to the high electrode wear, the depth of blind holes is difficult to control or broken taps removing can be use






it hole dia 1.524mm  








Friday 7 December 2018

Principle of wire cut EDM Advantages & Disadavantages EDM











Working Principle. In Electrical discharge machining; a potential difference is applied across the tool and w/p in pulse form. The tool and workpiece must be electrically conductive and a small gap is maintained in between them. The tool and workpiece is immersed in a dielectric medium (kerosene or deionized water

Advantages  &  Disadavantages EDM

   
  • Tolerances of +/- 0.005 can be achieved
  • Material hardness does not effect process – Tungsten Carbide – Stellite – Hastelloy – Nitralloy – Waspaloy – Nimonic – Inconel all can be successfully machined by EDM
  • Cutting complex shapes and thin walled configurations without distortion
  • EDM is a no-contact and no-force process, making it well suited for delicate or fragile parts that cannot take the stress of traditional machining
  • The EDM process leaves no burrs

Disadvantages

  • Only able to machine conductive materials
  • More expensive process than conventional milling or turning
internal spline make  very suitable machine