Advanced machining processes
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This document provides an overview of various advanced machining processes, including chemical milling, photochemical blanking, electrochemical machining, electrical discharge machining, laser beam machining, electron beam machining, plasma arc cutting, water jet machining, abrasive water jet machining, and abrasive jet machining. Each process is described along with considerations for its application. These non-traditional machining methods allow complex shapes to be cut in hard materials and offer alternatives to conventional processes for difficult-to-machine materials.
Advanced machining processes
- 2. OutlineOutline Chemical MillingChemical Milling Photochemical BlankingPhotochemical Blanking Electrochemical MachiningElectrochemical Machining Pulsed Electrochemical MachiningPulsed Electrochemical Machining Electrochemical GrindingElectrochemical Grinding Electrical-Discharge MachiningElectrical-Discharge Machining Electrical-Discharge GrindingElectrical-Discharge Grinding Electrical-Discharge Wire CuttingElectrical-Discharge Wire Cutting Laser-Beam MachiningLaser-Beam Machining Electron Beam MachiningElectron Beam Machining Plasma Arc CuttingPlasma Arc Cutting Water Jet MachiningWater Jet Machining Abrasive Water Jet MachiningAbrasive Water Jet Machining Abrasive Jet MachiningAbrasive Jet Machining
- 3. Examples of PartsExamples of Parts
- 4. Chemical MillingChemical Milling Produces shallow cavities on aProduces shallow cavities on a workpiece, usually to reduceworkpiece, usually to reduce weightweight The area affected by theThe area affected by the chemical reagent is controlledchemical reagent is controlled by masking or by partialby masking or by partial immersionimmersion
- 6. Chemical MillingChemical Milling Procedure:Procedure: 1.1. Relieve residual stresses toRelieve residual stresses to prevent warpingprevent warping 2.2. Clean the material surfaceClean the material surface 3.3. Apply masking materialApply masking material 4.4. Remove the masking on regionsRemove the masking on regions that require etchingthat require etching 5.5. Apply the reagentsApply the reagents 6.6. Wash the partWash the part 7.7. Remove remaining maskingRemove remaining masking 8.8. Additional finishing or chemicalAdditional finishing or chemical milling procedures may be usedmilling procedures may be used
- 7. Photochemical BlankingPhotochemical Blanking Uses chemicals andUses chemicals and photographic processes tophotographic processes to remove material, usually fromremove material, usually from a thin sheeta thin sheet Can produce complex shapes onCan produce complex shapes on metals as thin as .0025 mmmetals as thin as .0025 mm without forming burrswithout forming burrs
- 9. Examples of PartsExamples of Parts
- 10. Photochemical BlankingPhotochemical Blanking Procedure:Procedure: 1.1. Prepare the design at aPrepare the design at a magnification of up to 100x; makemagnification of up to 100x; make a photographic negative anda photographic negative and reduce it to the size of the partreduce it to the size of the part 2.2. Coat the blank withCoat the blank with photosensitive materialphotosensitive material 3.3. Place the negative over the partPlace the negative over the part and expose it to ultraviolet light toand expose it to ultraviolet light to harden the exposedharden the exposed photosensitive coatingphotosensitive coating 4.4. Dissolve the unexposed coatingDissolve the unexposed coating 5.5. Apply the chemical reagentApply the chemical reagent 6.6. Remove the masking and washRemove the masking and wash the partthe part
- 11. Chemical MachiningChemical Machining Design Considerations:Design Considerations: - Avoid sharp corners, deep narrowAvoid sharp corners, deep narrow cavities, steep tapers, foldedcavities, steep tapers, folded seams and porous workpiecesseams and porous workpieces - Undercuts may developUndercuts may develop - Most of the workpiece should beMost of the workpiece should be shaped by other processes toshaped by other processes to speed productionspeed production - Variations may occur dependingVariations may occur depending onhumidity and temperatureonhumidity and temperature - Computerized designs must beComputerized designs must be converted to a format compatibleconverted to a format compatible with the photochemical artworkwith the photochemical artwork equipmentequipment
- 12. ElectrochemicalElectrochemical MachiningMachining Uses an electrolyte and electricalUses an electrolyte and electrical current to ionize and removecurrent to ionize and remove metal atomsmetal atoms Can machine complex cavities inCan machine complex cavities in high-strength materialshigh-strength materials Leaves a burr-free surfaceLeaves a burr-free surface Not affected by the strength,Not affected by the strength, hardness or toughness of thehardness or toughness of the materialmaterial
- 15. ElectrochemicalElectrochemical MachiningMachining Design Considerations:Design Considerations: - The electrolyte erodes awayThe electrolyte erodes away sharp profilessharp profiles - It is difficult to controlIt is difficult to control electrolyte flow; irregularelectrolyte flow; irregular cavities may not be formedcavities may not be formed accuratelyaccurately - Allow for small taper in holesAllow for small taper in holes made this waymade this way
- 16. Pulsed ElectrochemicalPulsed Electrochemical MachiningMachining A form of electrochemicalA form of electrochemical machining; the current ismachining; the current is pulsed to eliminate the needpulsed to eliminate the need for high electrolyte flowfor high electrolyte flow Improves fatigue life of the partImproves fatigue life of the part
- 17. ElectrochemicalElectrochemical GrindingGrinding Uses a rotating cathodeUses a rotating cathode embedded with abrasiveembedded with abrasive particles for applicationsparticles for applications comparable to milling, grindingcomparable to milling, grinding and sawingand sawing Most of the metal removal isMost of the metal removal is done by the electrolyte,done by the electrolyte, resulting in very low tool wearresulting in very low tool wear Adaptable for honingAdaptable for honing
- 19. ElectrochemicalElectrochemical GrindingGrinding Design Considerations:Design Considerations: (in addition to those for(in addition to those for electrochemical machining)electrochemical machining) - Avoid sharp inside radiiAvoid sharp inside radii - Flat surfaces to be groundFlat surfaces to be ground should be narrower than theshould be narrower than the width of the grinding wheelwidth of the grinding wheel
- 20. Electrical-DischargeElectrical-Discharge MachiningMachining Uses a shaped electrode andUses a shaped electrode and electric sparks to removeelectric sparks to remove metal; discharges sparks atmetal; discharges sparks at about 50-500 kHzabout 50-500 kHz A dielectric (nonconductive) fluidA dielectric (nonconductive) fluid removes debris and acts as anremoves debris and acts as an insulator until the potentialinsulator until the potential difference is high enoughdifference is high enough Can be used on any materialCan be used on any material that conducts electricitythat conducts electricity
- 23. Electrical-DischargeElectrical-Discharge MachiningMachining Design Considerations:Design Considerations: - Design parts so that theDesign parts so that the electrodes can be madeelectrodes can be made economicallyeconomically - Avoid deep slots and narrowAvoid deep slots and narrow openingsopenings - Do not require very fineDo not require very fine surface finishsurface finish - Most of the material removalMost of the material removal should be done by othershould be done by other processes to speed productionprocesses to speed production
- 24. Electrical-DischargeElectrical-Discharge GrindingGrinding The grinding wheel lacksThe grinding wheel lacks abrasives and removesabrasives and removes material by electricalmaterial by electrical dischargesdischarges Can be combined withCan be combined with electrochemical grindingelectrochemical grinding Can be used for sawing, in whichCan be used for sawing, in which the saw has no teeththe saw has no teeth
- 25. Electrical-DischargeElectrical-Discharge Wire CuttingWire Cutting The wire moves through theThe wire moves through the workpiece like a band saw,workpiece like a band saw, removing material by electricalremoving material by electrical dischargedischarge Dielectric fluid is applied to theDielectric fluid is applied to the work areawork area The wire is generally used onlyThe wire is generally used only once; it is inexpensiveonce; it is inexpensive
- 27. Electrical-DischargeElectrical-Discharge Wire CuttingWire Cutting Example of a wire EDM machine Courtesy of Edison Industrial Service Center
- 28. Electrical-DischargeElectrical-Discharge Wire CuttingWire Cutting Example of a wire EDM machine Courtesy of Edison Industrial Service Center
- 29. Electrical-DischargeElectrical-Discharge Wire CuttingWire Cutting Example of a wire used for an EDM machine This wire has been used; the wave pattern was formed during take-up Courtesy of Edison Industrial Service Center
- 30. Electrical-DischargeElectrical-Discharge Wire CuttingWire Cutting Example of cores removed from a part using wire EDM to create the cavity in a high-pressure nozzle Holes were drilled in the interiors so that the wire could be strung through Courtesy of Edison Industrial Service Center
- 31. Laser-Beam MachiningLaser-Beam Machining Uses a concentrated beam ofUses a concentrated beam of light to vaporize part of thelight to vaporize part of the workpieceworkpiece Usually produces a roughUsually produces a rough surface with a heat-affectedsurface with a heat-affected zonezone Can cut holes as small as .005Can cut holes as small as .005 mm with depth/diameter ratiosmm with depth/diameter ratios of 50:1of 50:1
- 34. Laser-Beam MachiningLaser-Beam Machining Example of a part cut by laser-beam machining Splatter marks appear where the laser first cuts into the material
- 35. Laser-Beam MachiningLaser-Beam Machining Design Considerations:Design Considerations: - Non-reflective workpieceNon-reflective workpiece surfaces are preferablesurfaces are preferable - Sharp corners are difficult toSharp corners are difficult to produce; deep cuts produceproduce; deep cuts produce taperstapers - Consider the effects of highConsider the effects of high temperature on the workpiecetemperature on the workpiece materialmaterial
- 36. Electron BeamElectron Beam MachiningMachining Vaporizes material usingVaporizes material using electrons accelerated to 50-electrons accelerated to 50- 80% the speed of light80% the speed of light Produces finer surface finish andProduces finer surface finish and narrower cut width than othernarrower cut width than other thermal cutting processesthermal cutting processes Requires a vacuum; generatesRequires a vacuum; generates hazardous X rayshazardous X rays
- 38. Electron BeamElectron Beam MachiningMachining An electron beam in a very low-pressure atmosphere of helium
- 39. Plasma Arc CuttingPlasma Arc Cutting Uses plasma (ionized gas) toUses plasma (ionized gas) to rapidly vaporize materialrapidly vaporize material Material removal rates are muchMaterial removal rates are much higher than those for laserhigher than those for laser beam machining and electronbeam machining and electron beam machining; producesbeam machining; produces good surface finish and thin cutgood surface finish and thin cut widthwidth
- 40. Plasma Arc CuttingPlasma Arc Cutting
- 41. Plasma Arc CuttingPlasma Arc Cutting Close-up view of a plasma arc
- 42. Plasma Arc CuttingPlasma Arc Cutting
- 43. Electron Beam MachiningElectron Beam Machining and Plasma Arc Cuttingand Plasma Arc Cutting Design Considerations:Design Considerations: (in addition to those for laser-(in addition to those for laser- beam machining)beam machining) - Parts should match the size ofParts should match the size of the vacuum chamberthe vacuum chamber - Consider manufacturing theConsider manufacturing the part as a number of smallerpart as a number of smaller componentscomponents
- 44. Water Jet MachiningWater Jet Machining A pressurized jet of water cuts aA pressurized jet of water cuts a groove in the materialgroove in the material Effective for many nonmetallicEffective for many nonmetallic materialsmaterials Cuts can be started at anyCuts can be started at any location; does not producelocation; does not produce heat; produces very littleheat; produces very little burringburring
- 45. Water Jet MachiningWater Jet Machining
- 46. Water Jet MachiningWater Jet Machining
- 47. Abrasive Water JetAbrasive Water Jet MachiningMachining The water jet contains abrasiveThe water jet contains abrasive particles; this increases theparticles; this increases the material removal ratematerial removal rate Can cut metallic, nonmetallic,Can cut metallic, nonmetallic, and advanced compositeand advanced composite materialsmaterials Suitable for heat-sensitiveSuitable for heat-sensitive materialsmaterials
- 48. Abrasive Jet MachiningAbrasive Jet Machining A high-speed jet of dry air,A high-speed jet of dry air, nitrogen or carbon dioxidenitrogen or carbon dioxide carries abrasive particlescarries abrasive particles Good for cutting hard or brittleGood for cutting hard or brittle materialsmaterials Can be used for deburring,Can be used for deburring, cleaning, or removing oxidescleaning, or removing oxides or surface filmsor surface films
- 49. Abrasive Jet MachiningAbrasive Jet Machining
- 50. SummarySummary Advanced machining processesAdvanced machining processes offer alternatives whereoffer alternatives where conventional procedures wouldconventional procedures would be insufficient or uneconomicalbe insufficient or uneconomical
- 51. The End