Question

Explain the offset types available in the wire erosion machine?

Answer 1

There are three different offset types available in the wire erosion machine, namely:

1) Sinker erosion machine

2) Wire Electric Discharge machine

3) Hole drilling erosion machine

1) Sinker erosion machine:

It is a manufacturing process that precisely removes material from conductive materials using an electrode. Similar to pushing a form into soft material, the electrode leaves a negative imprint in the workpiece. The physical process is a little more complicated: In a small gap between workpiece and electrode, a discharge occurs that removes material through melting or vaporizing. For this process, the electrode and the workpiece have to be submerged in a dielectric fluid.

The principle behind this process is the ability of controlled electric sparks to erode material. The workpiece and electrode do not touch during this porcess. In between is a gap that is roughly as thick as a human hair. The amount of removed material with a single spark is small, yet the discharge occurs roughly several 100,000 times a second.

While the electrode is moved closer to the workpiece, the electric field in the gap, also known as spark gap, increases until it reaches the breakdown volume. For this process, it is necessary that the fluid in which this discharge occurs is not conductive, or dielectric. The discharge causes strong heating of the material, melting away small amounts of material. This excess material is removed with the steady flow of the dielectric fluid. The liquid is also useful for cooling during the machining. Moreover, it is necessary for controlling the sparks.

2) Wire Electric discharge machine:

In Wire EDM a thin wire is used to cut the work piece. In this case, the wire works as the electrode. During the machining, the wire is constantly coming from an automated feed with a spool. If the cut has to be made in the middle rather than the outside of the workpiece, small hole drilling EDM is used to make a hole in the workpiece through which the wire is threaded afterwards.

The wire is held with diamond guides. Usually the liquid is deionized water. The wire is often made from brass or copper.

3) Hole drilling erosion machine:

As the name suggests, this process is used for drilling holes. Compared with traditional drilling methods, EDM is able to machine extremely small and deep holes. Additionally, EDM drilled holes don't need any deburring. The electrodes in this process are tubular and the dielectric fluid is fed through the electrode itself.