NON CONVENTIONAL MACHINING UPTU Notes（非传统加工UPTU笔记）.pdf

NON TRADITIONAL MANUFACTURING PROCESSES The general grouping of some of the typical non-traditional processes are shown below: o Mechanical Processes USM AJM WJM and AWJM o Thermal Processes EBM LBM PAM EDM and WEDM o Electrical Processes ECM EDG EJD o Chemical Processes Chemical milling Photo chemical machining By- Animesh Pal animesh14@ Page 1 ELECTRIC DISCHARGE MACHINING (EDM) EDM is a thermal erosion process whereby material is melted and vaporized from an electrically conducive workpiece immersed in a liquid dielectric with a series of spark discharges between the tool electrode and the workpiece created by a power supply. EDM is mainly used to machine difficult-to-machine materials and high strength temperature resistant alloys. EDM can be used to machine difficult geometries in small batches or even on job-shop basis. Work material to be machined by EDM has to be electrically conductive. WORKING PRINCIPLE OF EDM In EDM, a potential difference is applied between the tool and workpiece. Both the tool and the work material are to be conductors of electricity. The tool and the work material are immersed in a dielectric medium. Generally kerosene or deionised water is used as the dielectric medium. A gap is maintained between the tool and the workpiece. Depending upon the applied potential difference and the gap between the tool and workpie