# Nontraditional manufacturing



## aboalzooz2002 (5 فبراير 2009)

كل من لة الرغبة في معرفة طرق التصنيع الغير تقليدية​*:63::63:
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*​*NONTRADITIONAL MANUFACTURING*​*
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*​*PROCESSES*​ ​​ *Definition*​​ A group of processes that remove excess material by various techniques involving, mechanical, thermal, electrical, or chemical energy (or combinations of these energies) .​​ They 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.​​ ​​ *Importance of Nontraditional Processes*​​ »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 readily be accomplished by conventional machining.​​ »Need to avoid surface damage that often accompanies conventional machining​​ ​​ *Classification of Nontraditional Processes*​​ *»Mechanical* - typical form of mechanical action is abrasives or fluid (or both).​​ *»Electrical* -electrochemical energy to remove material (reverse of electroplating).​​ *»Thermal* –thermal energy usually applied to small portion of work surface, causing that portion to be fused and/or vaporized​​ *»Chemical*- chemical etchants selectively remove material from portions of workpart, while other portions are protected by a mask​​ 
*Mechanical Energy Processes*​​ »Ultrasonic machining(USM*)*​​ »Water jet cutting(WJC)​​ »Abrasive water jet cutting(AWJC)​​ »Abrasive jet machining(AJM)​​ ​​ *Ultrasonic machining(USM) *​​ Abrasives contained in a slurry are driven at high velocity against work by a tool vibrating at low amplitude and high frequencyTool oscillation is perpendicular to work surfaceAbrasives accomplish material removalTool is fed slowly into workShape of tool is formed into part​​ ​​ *USM Applications*​​ Hard, brittle work materials such as ceramics, glass, and carbides.​​ Also successful on certain metals, such as stainless steel and titanium.​​ Shapes include non-round holes, holes along a curved axis.​​ *Water Jet Cutting (WJC)*​​ Uses high pressure, high velocity stream of water directed at work surface for cutting.​​ ​​ *WJC Applications:*​​ Used to cut narrow slits in flat stock such as plastic, textiles, composites, carpet, leather, and cardboard.​​ Not suitable for brittle materials (e.g., glass).​​ No environmental pollution.​​ Ease of automation​​ ​​ *Abrasive Water Jet Cutting (AWJC)*​​ When WJC is used on metals, abrasive particles must be added to jet stream usually.​​ ​​ *Abrasive Jet Machining (AJM)*​​ High velocity stream of gas containing small abrasive particles​​ ​​ *AJM Applications:*​​ Usually performed manually by operator who directs nozzle.​​ Normally used as a finishing process rather than cutting process.​​ Applications: deburring, cleaning, and polishing.​​ Work materials: thin flat stock of hard, brittle materials (e.g., glass, silicon, mica, ceramics)​​ ​​ *Electrochemical Machining Processes*​​ Electrical energy is used in combination with chemical reactions to remove material.​​ Work material must be a conductor​​ Reverse of electroplating​​ *Processes:*​​ »Electrochemical machining (ECM)​​ »Electrochemical deburring (ECD)​​ »Electrochemical grinding (ECG)​​ ​​ *Electrochemical Machining (ECM)*​​ Material removal by anodic dissolution, using electrode (tool) in close proximity to work but separated by a rapidly flowing electrolyte​​ *ECM Operation:*​​ Material is deplatedfrom anode workpiece (positive pole) and transported to a cathode tool (negative pole) in an electrolyte bath.​​ Electrolyte flows rapidly between material, so it does not plate onto tool.​​ Electrode materials: copper, brass, or stainless steel​​ *ECM Applications*​​ ​​ Die sinking -irregular shapes and contours for forging dies, plastic​​ molds, and other tools.​​ Multiple hole drilling -many holes can be drilled simultaneously with ECM.​​ Holes that are not round, since rotating drill is not used in ECM​​ Burr-free surface, no thermal damage, no tool wear​​ Irregular cavities may not be produced to the desired shape, since controlling electrolyte flow is difficult​​ ​​ *Electrochemical Grinding (ECG)*​​ ​​ Special form of ECM in which grinding wheel with conductive bond material augments anodic dissolution of metal part surface​​ ​​ *Thermal Energy Processes*​​ ​​ Very high local temperatures​​ Material is removed by fusion or vaporization.​​ Physical and metallurgical damage to the new work surface.​​ In some cases, resulting finish is so poor that subsequent processing is required.​​ *Processes..*​​ »Electric discharge machining(EDM).​​ »Wire electricdischarge machining (Wire EDM).​​ »Electron beam machining(EBM).​​ »Laser beam machining(LBM).​​ »Plasma arc machining (PAM).​​ ​​ *Electric Discharge Processes*​​ ​​ Metal removal by a series of discrete electrical discharges (sparks) causing localized temperatures high enough to melt or vaporize the metal.​​ Can be used only on electrically conducting work materials.​​ Two main processe:​​ »Electric discharge machining.​​ »Wire electric discharge machining.​​ ​ ​ ​ ​ ​ ​ ​ *EDM Operation*​​ One of the most widely used nontraditional processes.​​ Shape of finished work surface produced by a shape of electrode tool​​ Sparks occur across a small gap between tool and work.​​ Requires dielectric fluid which creates a path for each discharge​​ as fluid becomes ionized in the gap.​​ Material removal rate depends on melting point of work material.​​ Tooling for many mechanical processes: molds for plastic injection molding, extrusion dies, wire drawing dies, forging dies.​​ Production parts: delicate parts not rigid enough to withstand conventional cutting forces, machining of hard metals​​ ​​ *Wire EDM*​​ Special form of EDM uses small diameter wire as electrode to cut a narrow slot in workpiece​​ ​​ *Wire EDM Applications*​​ Used to cut plates as thick as 300 mm for making punches, tools and dies from hard metals, for cutting intricate components for electronics. industry​​ Wire material ; brass, copper, tungsten.​​ ​​ *Electron Beam Machining (EBM)*​​ Uses high velocity stream of electrons focused on workpiece surface to remove material by melting and vaporization.​​ *EBM Applications:*​​ Source of energy is high-velocity electrons.​​ Applications are similar to those for LBM, generally used for very accurate cutting of metals.​​ Works on any material.​​ Ideal for micromachining..​​ » Drilling small diameter holes(down to 0.05 mm) as compared to depth.​​ » Cutting slots only about 0.025 mm wide.​​ ​​ *Laser Beam Machining (LBM)*​​ Uses the light energy from a laser to remove material by vaporization and ablation.​​ Laser (Light amplification by stimulated emission of radiation) converts electrical energy into a highly coherent light beam.​​ *LBM Applications:*​​ Used in drilling and cutting metals, nonmetals and composite materials in electronics and automative industries.​​ Drilling small diameter holes -down to 0.025 m.​​ ​​ *Plasma Arc Cutting (PAC)*​​ Uses plasma stream operating at very high temperatures to cut metal by melting.​​ Source of energy is high-velocity plasma beams (ionized gas) in PAC.​​ *Applications of PAC:*​​ Most applications of PAC involve cutting of flat metal sheets and plates.​​ Hole piercing and cutting along a defined path.​​ Can be operated by hand-held torch or automated by CNC.​​ Can cut any electrically conductive metal.​​ Most frequently cut metals: carbon steel, stainless steel, aluminum.​​ ​​ *Chemical Machining*​​ Material removal through contact with a strong chemical etchant.​​ Processes include:​​ » Chemical milling.​​ » Chemical blanking.​​ » Photochemical machining.​​ All utilize the same mechanism of material removal​​ *Applications of Chemical Milling:*​​ Remove material from aircraft wing and fuselage panels for weight reduction. Applicable to large parts where substantial amounts of metal are removed.​​ Shallow cavities on plates, sheets, forgings and extrusions.​​ Maximum depth of removal 12mm.​​ May result in some surface damage.​​ Mainly used in aerospace industry, also in the fabrication of microelectronic devices.​​ ​​ *Chemical Blanking*​​ Uses chemical erosion to cut very thin sheetmetal parts -down to 0.025 mm thick and/or for intricate cutting patterns.​​ Conventional punch and die does not work because stamping forces damage the thin sheetmetal, or tooling cost is prohibitive, or both.​​


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