Modern manufacturing process: Mechanical processes, Electrochemical processes,

Modern manufacturing process

Modern manufacturing techniques have often been classified according to the principal type of energy utilized to remove or add material— mechanical, electrical, thermal, and chemical.

Mechanical processes

Ultrasonic machining and abrasive jet machining are the two primary (nontraditional) mechanical processes. Material is removed through erosion, where hard particles (in a liquid slurry) are forced into contact with the workpiece at very high speeds.



Electrochemical processes

Electrochemical machining is the primary representative of this group. It uses electrolysis to remove material from a conductive workpiece submerged in an electrolyte bath; particles depart from the anodic workpiece surface toward a cathodic tool and get swept away by the high-speed flowing electrolyte liquid.


Thermal processes

Electrical discharge machining, electron beam machining, and laser beam machining are the three primary thermal energy–based processes. Metal removal in electrical discharge machining is achieved through high-frequency sparks hitting the surface of a workpiece submerged in a dielectric liquid bath. In electron beam machining, a high-speed stream of electrons impinge on a very small focused spot on the surface of the workpiece and, as in electrical discharge machining, vaporize the material (this is preferably carried out in a vacuum chamber). Laser beam machining is utilized for the cutting of thick-walled parts as well as micromachining of very thin walled plates through fusion. Lasers are also commonly used in additive processes, lithography-based or sintering-based, for the solidification of liquids and powders. Naturally, the types of lasers used in these applications are quite varied.



Chemical processes

Chemicalmachining,alsoknownasetching, refers to the removal of material from metal surfaces through purely chemical reactions. It can favorably be used in etching shallow depths (or holes) in metals such as aluminum, titanium, and copper, which are vulnerable to erosion by certain chemicals (most notably hydrochloric, nitric, and sulphuric acids). Due to difficulties in focusing on small areas, most chemical processes use chemical-resistant masks to protect surfaces from unwanted etching. 


All above-mentioned modern material removal or material additive processes are characterized by the following common features: higher power consumption and lower material removal (or additive) rates than traditional fabrication processes, but yielding better surface finish and integrity (i.e., less residual stress and fewer microcracks). A large number of these processes also are capable of fabricating features with dimensions several orders of magnitude less than those obtainable by traditional processes.

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