Lecture 06: Non-traditional Machining using Thermal Energy

Vocabulary flashcards for non-traditional machining techniques using thermal energy.

Thermal Removing Processes

Processes where thermal energy, from a heat source, melts or vaporizes material.

Heat Sources (Thermal Machining)

Electric discharge (Arc), Electron beam, Laser beam, Plasma.

Thermal Machining Technologies

Electrical Discharge Machining (EDM), Electron Beam Machining (EBM), Laser Beam Machining (LBM), Plasma Beam Machining (PBM).

Heat-Affected Zone

Area on the workpiece altered by the heat from thermal removal processes, sometimes called a recast layer.

Electro-optical-thermal processes

Material removal mechanisms that involve electrical energy to generate high-energy electrons (EBM) or coherent photons (LBM).

Electron Beam Machining (EBM)

A thermal machining process using a high-velocity, focused electron beam to melt and vaporize material.

Electromagnetic Lens (EBM)

Focuses electron beam to a small diameter on the work surface in EBM.

Vacuum (EBM)

Used in EBM to minimize contamination and electron collisions.

Thermo-ionic emission

Emission of electrons from a heated cathode in the electron gun of an EBM machine.

Magnetic lenses (EBM)

Focus the electron beam to the surface of the workpiece using Lorentz forces.

EBM Process Parameters

Accelerating voltage, beam current, pulse duration, energy per pulse, power per pulse, lens current, spot size, power density.

Backing Material (EBM Drilling)

Used on the rear side of the workpiece to expel molten material during drilling.

X-rays (EBM)

Health hazard produced by the interaction of the electron beam with the workpiece.

Laser (LASER)

Light Amplification by Stimulated Emission of Radiation. Device which produces highly directional light.

Laser properties

Coherence, directionality, mono-chromacity, and high intensity.

Spontaneous Emission

Photons emitted in a random direction at a random phase.

Stimulated Emission

Atoms emitted during stimulated emission are forced into phase by the radiation field.

Main laser components

Laser active medium, light amplifying medium and an optical resonator which usually consists of a number of mirrors.

Solid-state laser

Laser that uses solid as a laser medium. In these lasers, glass or crystalline materials are used.

Doping

The process of adding impurities to the substance.

Gas laser

Laser where the laser medium or gain medium is made up of the mixture of gases, packed up into a glass tube, acting as an active medium or laser medium.

Liquid laser

Laser that uses the liquid as laser medium.

Pump source (Semiconductor lasers)

Electrical energy.

Semiconductor laser

Laser diode.

Beam Benders

Mirrors that bounce the laser in different directions before it is focused onto the plate.

Kerf width

Width of the material removed by a cutting process. Laser cutting has a very small one.

Gas-assisted laser cutting

Gas is blown into the cut to clear away molten metals, or other materials in the cutting zone.

Plasma

Highly conductive ion-electron gas, a collection of charged particles, containing about equal numbers of positive ions and electrons.

Plasma Arc Machining (PAM)

Similar to PBM, mainly used for cutting thick sections of electrically conductive materials.