Advanced Machining Processes Vocabulary

Vocabulary terms and definitions covering non-conventional advanced machining processes including Water Jet Machining, Abrasive Water Jet Machining, Laser Beam Machining, and Electron Beam Machining.

Water Jet Machining (WJM)

A non-conventional machining process that utilizes a high-velocity jet of water to remove material precisely from workpiece surfaces via mechanical erosion, particularly suitable for soft materials such as paper, plastic, rubber, and wood.

Water Hammering Effect

A phenomenon in WJM where the impact of a high-velocity water jet striking a workpiece converts kinetic energy to pressure energy, raising transient localized pressure up to three times the normal stagnation pressure.

Intensifier

A reciprocating plunger pump driven by a high-pressure hydraulic oil pump in a WJM system that increases water pressure to deliver ultra-high-pressure water to an accumulator.

Accumulator

A high-pressure water reservoir in a WJM system that eliminates pressure fluctuations coming from the intensifier and ensures a continuous supply of pressurized water to the nozzle.

Abrasive Water Jet Machining (AWJM)

An advanced non-conventional process where fine-grained abrasive particles are mixed with water and focused through a nozzle to erode soft or hard difficult-to-machine materials through micro-cutting, fatigue, and brittle fracture.

Laser Beam Machining (LBM)

A precise non-contact thermal manufacturing process that utilizes a focused laser beam to remove material from a workpiece through melting, vaporization, or chemical degradation.

Stimulated Emission

The process where a photon interacts with an excited atom at a high energy level, causing it to decay and emit an additional photon with identical wavelength, phase, direction, and energy.

Population Inversion

A state in a lasing material where a powerful energy source excites the majority of atoms or molecules into higher energy levels compared to lower energy ground states.

Beam Divergence

The angle of beam spread or the increase in laser beam diameter per unit distance of travel, which depends on the average output power of the laser.

Depth of Focus ($\Delta f$)

The distance along the laser beam axis over which the waist diameter does not change appreciably, calculated using the formula $\Delta f = \frac{2 W f}{D_i}$.

Trepanning

A laser cutting process used to produce holes larger than $1.2\,\text{mm}$ in diameter or noncircular profiles by moving the laser beam or workpiece along a programmed CNC path.

Electron Beam Machining (EBM)

A thermal non-conventional process that uses a focused beam of high-velocity electrons accelerated in a vacuum chamber to remove material via localized melting and vaporization.

Vacuum Chamber (EBM)

An evacuated workspace maintained at $10^{-4}\text{ Torr}$ to $10^{-5}\text{ Torr}$ in EBM to prevent electron scattering from collisions with air molecules and to prevent filament oxidation.

Kerf Width

The width of the cut or slot created by a cutting process, which affects dimensional accuracy and determines the amount of material removed.

Material Removal Rate (MRR)

The volume of material removed from a workpiece per unit of time, calculated using the relation $\text{MRR} = \text{Cutting Speed} \times \text{Feed Rate} \times \text{Depth of Cut}$.

Surface Roughness ($R_a$)

A measure of the fine irregularities on a machined surface, quantified by Roughness Average ($R_a$) as the average height deviation of surface peaks and valleys from an ideal plane in micrometers ($\mu\text{m}$).