Ion beam machining

Ion beam machining is generally a surface finishing process in which the material removal takes place by sputtering of ions.
It is also called the etching process. This is a different process from electric discharge, electron beam, laser beam and plasma arc machining. 

Working Principle :

This process is very simple. It consists of bombarding the work with accelerated ions which collide with the surface atoms of the work. Each bombarding ions, as a result of collisions, dislodges surface layer.
It consists of an electron gun discharging free electrons into a chamber filled with argon gas. The gas is ionized by electrons. The top of the chamber is known as ion-beam generating apparatus. At the other end, the workpiece is fixed to a table which can be oscillated and rotated so that different points on the work surface can be subjected to an ion beam.

Ion beam machining

Accuracy :

  • Etching rates vary up to 2000 Å per min.
  • Accuracy of the etching process is considerably high mainly due to the small amount of material removal.
  • Tolerances in the vicinity of + 50  Å  to - 50  Å  are possible.
Applications of IBM :
  • It is applied mostly in micro-machining of electronic components.
  • Typical materials that can be etched included glass, alumina, quartz, crystal, silica, agates, porcelains, numerous metals, cermets and oxides.
  • It is also be used to deposit materials such as platinum, tungsten and silicon oxide insulators on another material substrate.
Advantages of IBM :
  • IBM is almost universal.
  • No chemical reagents or etching are required.
  • Etching rates are easily controlled.
  • There is no undercutting as with another chemical etching process.
Disadvantages of IBM :
  • IBM is relatively expensive.
  • Etching rates are slow.
  • No heat is generated so there is little possibility of some thermal or radiation damage.