a09 non traditional manufacturing processes(1) -...
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Department of Mechanical EngineeringChung-Ang University
Non traditional manufacturing processes
(Chapter 24 & 34)
Seok-min [email protected]
Department of Mechanical EngineeringChung-Ang University
Nontraditional Processes (Ch. 24)A group of processes that remove excess material by
various techniques involving mechanical, thermal, electrical, or chemical energy (or combinations of these energies) but do not use a sharp cutting tool in the conventional sense
Developed since World War II in response to new and unusual machining requirements that could not be satisfied by conventional methods
Department of Mechanical EngineeringChung-Ang University
Why Nontraditional Processes are Important
Need to machine newly developed metals and non-metals with special properties that make them difficult or impossible to machine by conventional methods
Need for unusual and/or complex part geometries that cannot easily be accomplished by conventional machining
Need to avoid surface damage that often accompanies conventional machining
Department of Mechanical EngineeringChung-Ang University
Classification of Nontraditional Processes by Type of Energy Used
Electrical - electrochemical energy to remove material (reverse of electroplating)
Mechanical - erosion of work material by a high velocity stream of abrasives or fluid (or both) is the typical form of mechanical action
Thermal – thermal energy usually applied to small portion of work surface, causing that portion to be removed by fusion and/or vaporization
Chemical – chemical etchants selectively remove material from portions of workpart, while other portions are protected by a mask
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Electrochemical Machining (ECM)Material removal by anodic dissolution, using electrode (tool)
in close proximity to the work but separated by a rapidly flowing electrolyte
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Electrochemical Deburring (ECD) Adaptation of ECM to remove burrs or round sharp corners on
holes in metal parts produced by conventional through-hole drilling
Department of Mechanical EngineeringChung-Ang University
Electrochemical Grinding (ECG) Special form of ECM in which a
grinding wheel with conductive bond material is used to augment anodic dissolution of metal part surface
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Electric Discharge Machining (EDM)
(a) overall setup, and (b) close-up view of gap, showing discharge and metal removal
(a)
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Wire EDM Special form of EDM that uses small diameter wire as electrode to
cut a narrow kerf in work
http://www.youtube.com/watch?v=pBueWfzb7P0
Department of Mechanical EngineeringChung-Ang University
Ultrasonic Machining (USM) I Abrasives contained in a slurry are driven at high velocity
against work by a tool vibrating at low amplitude and high frequency
Tool oscillation is perpendicular to work surface
Tool is fed slowly into work
Shape of tool is formed in part
Department of Mechanical EngineeringChung-Ang University
Ultrasonic Machining (USM) II
Department of Mechanical EngineeringChung-Ang University
Water Jet Cutting (WJC) Uses a fine, high pressure, high velocity stream of water
directed at work surface for cutting
http://www.youtube.com/watch?v=i6l-YfnyAhI
Department of Mechanical EngineeringChung-Ang University
Abrasive Jet Machining (AJM) High velocity stream of gas containing small abrasive particles
Department of Mechanical EngineeringChung-Ang University
Laser Beam Machining (LBM) Uses the light energy from a laser to remove material by
vaporization and ablation
Department of Mechanical EngineeringChung-Ang University
Electron Beam Machining (EBM) Uses high velocity stream of electrons focused on workpiece
surface to remove material by melting and vaporization
Department of Mechanical EngineeringChung-Ang University
Integrated Circuit (IC) A collection of electronic devices such as transistors,
diodes, and resistors that have been fabricated and electrically intraconnected onto a small flat chip of semiconductor material
Silicon (Si) - most widely used semiconductor material for ICs
16http://www.youtube.com/watch?v=-Wfsl1eDim8
Department of Mechanical EngineeringChung-Ang University
Packaging of an integrated circuit chip: (a) cutaway view showing the chip attached to a lead frame and encapsulated in a plastic enclosure, and (b) the package as it would appear to a user. This type of package is called a dual in-line package (DIP).
IC Package (DIP)
17http://www.youtube.com/watch?v=Q31VCcEbHKk
http://www.youtube.com/watch?NR=1&v=VwOEQodkBrY&feature=endscreen
Department of Mechanical EngineeringChung-Ang University
Sequence of processing steps in the production of integrated circuits: (1) pure silicon is formed from the molten state into an ingot and then sliced into wafers; (2) fabrication of integrated circuits on the wafer surface; and (3) wafer is cut into chips and packaged.
Processing Sequence for Silicon ICs
18http://www.youtube.com/watch?v=W62sbKA50XM&feature=related
Department of Mechanical EngineeringChung-Ang University
Czochralski process for growing single crystal ingots of silicon: (a) initial setup prior to start of crystal pulling, and (b) during crystal pulling to form the boule.
Crystal Growing
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Department of Mechanical EngineeringChung-Ang University
Grinding operations used in shaping the silicon ingot: (a) a form of cylindrical grinding provides diameter and roundness control, and (b) a flat ground on the cylinder.
Grinding Operations on ingot
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Department of Mechanical EngineeringChung-Ang University
Wafer Slicing
Wafer slicing using a diamond abrasive cut-off saw.
Thickness : 30 µm
Wafers are cut 0.5-0.7 mm thick, greater thicknesses for larger wafer diameters To minimize loss, blades are very thin: thickness ~ 0.33 mm
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