Some Non-Traditional Machining Processes

  • To introduce students non-conventional manufacturing processes.

  • Laser-beam machining (LBM) is accomplished by precisely manipulating a beam of coherent light to vaporize unwanted material. LBM is particularly suited to making accurately placed holes. It can be used to perform precision micro-machining on all microelectronic substrates such as ceramic, silicon, diamond, and graphite.

  • Abrasive water jet cutting systems (abrasive jet) use a combination of water and garnet to cut through materials considered ’unmachineable’ by conventional cutting methods.

  • Electrical Discharge Machining (EDM), also known as spark erosion, employs electrical energy to remove metal from the workpiece without touching it. A pulsating high- frequency electric current is applied between the tool point and the workpiece, causing sparks to jump the gap and vaporize small areas of the workpiece. Because no cutting forces are involved, light, delicate operations can be performed on thin workpieces. EDM can produce shapes unobtainable by any conventional machining process.

  • Ultrasonic machining (USM) is a mechanical material removal process used to erode holes and cavities in hard or brittle workpieces by using shaped tools, high frequency mechanical motion, and an abrasive slurry. A relatively soft tool is shaped as desired and vibrated against the workpiece while a mixture of fine abrasive and water flows between them. The friction of the abrasive particles gradually cuts the workpiece. Materials such as hardened steel, carbides, rubies, quartz, diamonds, and glass can easily be machined by USM. Ultrasonic machining is able to effectively machine all materials harder than HRc 40, whether or not the material is an electrical conductor or an insulator.

Solved Examples

Solved Example:

55-12-01

The process utilizing mainly thermal energy for removing material is: (GATE ME 2014- Shift III)

Solution:

  • USM = Ultra Sonic Machining

  • ECM = ElectroChemical Machining

  • AJM = Abrasive Jet Machining

  • LBM = Laser Beam Machining

Correct Answer: B

Solved Example:

55-12-02

Which one of the folloiwng TRUE for the ultrasonic machining (USM) process? ISRO MCF Tech Asst. Mech. June 2019)

Solution:

  1. Wrong : In USM, the tool vibrates at high may be sonic frequency.

  2. Wrong : USM uses transducers so as to produce low amplitude vibration

  3. Wrong : USM is an excellent process for machining hard and brittle materials.

  4. In USM slurry comprising abrasive particles and water are often uses to remove material from the workpiece by abrasion or impact grinding action.

Correct Answer: D