Understanding What EDM Die Sinking is All About
11 May 2020Electrical Discharge Machine(EDM) Die-sinking, also called as a cavity type EDM or volume EDM, consists of an electrode and work piece submerged in an insulating liquid such as, more typically, oil or, less frequently, other dielectric fluids. The electrode and work piece are connected to a suitable power supply. The power supply generates an electrical potential between the two parts. As the electrode approaches the work piece, dielectric breakdown occurs in the fluid, forming a plasma channel, and a small spark jumps. Read further below to understand what EDM Die Sinking is all about.
EDM Die Sinking Basics
The sparks in EDM Die Sinking usually strike one at a time because it is very unlikely that different locations in the inter-electrode space have the identical local electrical characteristics which would enable a spark to occur simultaneously in all such locations. These sparks happen in huge numbers at seemingly random locations between the electrode and the work piece. As the base metal is eroded, and the spark gap subsequently increased, the electrode is lowered automatically by the machine so that the process can continue uninterrupted. Several hundred thousand sparks occur per second, with the actual duty cycle carefully controlled by the setup parameters.
These controlling cycles are sometimes known as “on time” and “off time”. The on time setting determines the length or duration of the spark. Hence, a longer on time produces a deeper cavity for that spark and all subsequent sparks for that cycle, creating a rougher finish on the work piece. The reverse is true for a shorter on time. Off time is the period of time that one spark is replaced by another.
A longer off time, for example, allows the flushing of dielectric fluid through a nozzle to clean out the eroded debris, thereby avoiding a short circuit. These settings can be maintained in microseconds. The typical part geometry is a complex 3D shape, often with small or odd shaped angles. Vertical, orbital, vectorial, directional, helical, conical, rotational, spin and indexing machining cycles are also used.
Advantages of EDM Die Sinking
EDM Die Sinking has been advantageous in the machining industry for being able to create complex shapes that would otherwise be difficult to produce with conventional cutting tools. They are also extremely hard material to very close tolerances. They are composed of very small work pieces where conventional cutting tools may damage the part from excess cutting tool pressure. Since, there is no direct contact between tool and work piece, delicate sections and weak materials can be machined without any distortion. Aside from the abovementioned, a good surface finish can be obtained and very fine holes can be drilled using EDM Die Sinking.
Disadvantages of EDM Die Sinking
It is a known fact that there will be flaws in the EDM Die Sinking. For one, it has a slow rate of material removal. Also, there could be a potential fire hazard associated with use of combustible oil based dielectrics. There is also an additional time and cost used for creating electrodes for ram/sinker EDM. Aside from that, the specific power consumption is very high and electrically non-conductive materials can be machined only with specific set-up of the process.
There is still a lot more to know about EDM Die Sinking if you consult Aero Spec Engineering . We are a manufacturing facility that possess the latest CAD & Cam software to drive quality brand multi axis 3,4, & 5 simultaneous axis CNC machining centres and CNC multi axis lathes with live driven tooling and bar feeding.
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