《工程测试与信号处理》课程教学资源（文献资料）Abrasive Waterjet Machining（PPT）

Abrasive WaterjetMachiningChuck GallantBaris AkcoraAndy Grueninger

Chuck Gallant Baris Akcora Andy Grueninger

Introduction to WaterjetFastest growing machining process One of the most versatile machining processes Compliments other technologies such as milling,laser, EDM, plasma and routersTrue cold cutting process - no HAZ, mechanicalstresses or operator and environmental hazardsNot limited to machining - food industryapplications

Introduction to Waterjet  Fastest growing machining process  One of the most versatile machining processes  Compliments other technologies such as milling, laser, EDM, plasma and routers  True cold cutting process – no HAZ, mechanical stresses or operator and environmental hazards  Not limited to machining – food industry applications

History Dr. Franz in 195o's first studied UHP water cutting forforestry and wood cutting (pure WJ)1979 Dr. Mohamed Hashish added abrasive particles toincrease cutting force and ability to cut hard materialsincluding steel, glass and concrete (abrasive WJ)First commercial use was in automotive industry to cutglass in 1983Soon after, adopted by aerospace industry for cuttinghigh-strength materials like Inconel, stainless steeland titanium as well as composites like carbon fiber

History  Dr. Franz in 1950’s first studied UHP water cutting for forestry and wood cutting (pure WJ)  1979 Dr. Mohamed Hashish added abrasive particles to increase cutting force and ability to cut hard materials including steel, glass and concrete (abrasive WJ)  First commercial use was in automotive industry to cut glass in 1983  Soon after, adopted by aerospace industry for cutting high-strength materials like Inconel, stainless steel and titanium as well as composites like carbon fiber

Pure WJCutting Pure cuts soft materials - corrugated cardboarddisposable diapers, tissue papers, automotive interiorsVery thin stream (0.004-0.010 dia)Extremely detailed geometryVery little material loss due to cuttingCan cut thick, soft, light materials like fiberglassinsulation up to 24" thick or thin, fragile materialsVery low cutting forces and simple fixturingWater jet erodes work at kerf line into small particles

Pure WJ Cutting  Pure cuts soft materials – corrugated cardboard, disposable diapers, tissue papers, automotive interiors  Very thin stream (0.004-0.010 dia)  Extremely detailed geometry  Very little material loss due to cutting  Can cut thick, soft, light materials like fiberglass insulation up to 24” thick or thin, fragile materials  Very low cutting forces and simple fixturing  Water jet erodes work at kerf line into small particles

Pure WJ Cutting cont.Water inlet pressurebetween 2ok-6ok psiForced through hole inInletWaterjewel 0.007-0.020" diaSapphires, Rubies with50-10o hour lifeJewelDiamond with 8oo.2,ooo hour life, butthey are pricey

Pure WJ Cutting cont.  Water inlet pressure between 20k-60k psi  Forced through hole in jewel 0.007-0.020” dia  Sapphires, Rubies with 50-100 hour life  Diamond with 800- 2,000 hour life, but they are pricey

AbrasiveWJ CuttingUsed to cut much harder materialsWater is not used directly to cut material as in Pure,instead water is used to accelerate abrasive particleswhich do the cutting8o-mesh garnet (sandpaper) is typically used though50 and 120-mesh is also usedStandoff distance between mixing tube and workpartis typically 0.010-0.2oo - important to keep to aminimum to keep a good surface finish

Abrasive WJ Cutting  Used to cut much harder materials  Water is not used directly to cut material as in Pure, instead water is used to accelerate abrasive particles which do the cutting  80-mesh garnet (sandpaper) is typically used though 50 and 120-mesh is also used  Standoff distance between mixing tube and workpart is typically 0.010-0.200 – important to keep to a minimum to keep a good surface finish

Abrasive WJ Cutting cont.Evolution of mixing tubeInletWatertechnologyStandard Tungsten Carbidelasts 4-6 hours (not used muchJewelanymore)-AbrasivePremium Composite Carbidelasts 100-150 h0ursConsumables include water,Guardabrasive, orifice and mixingMixingTubetube

Abrasive WJ Cutting cont.  Evolution of mixing tube technology  Standard Tungsten Carbide lasts 4-6 hours (not used much anymore)  Premium Composite Carbide lasts 100-150 hours  Consumables include water, abrasive, orifice and mixing tube

TolerancesTypically +/- 0.005 inchMachines usually have repeatability of o.ooi inchComparativelytraditional machining centers can holdtolerances of o.oooi inch with similar repeatabilityWJ tolerance range is good for many applicationswhere critical tolerances are not crucial to workpartdesign

Tolerances  Typically +/- 0.005 inch  Machines usually have repeatability of 0.001 inch  Comparatively traditional machining centers can hold tolerances 0f 0.0001 inch with similar repeatability  WJ tolerance range is good for many applications where critical tolerances are not crucial to workpart design

SetupTypical Machining CenterSOMAXControllerMNozzle255PumpniMichinisgCenteAbrasivedeliverysystemMotionsystemCatchtank

Setup

When is it Practical?Thecutteriscommonlyconnectedtoahigh-pressurewaterpump,wherethe wateris then ejected from theinAbrasivenozzle,cutting through the materialPowderby spraying it with the jet of high.speedwater.It's practical to useit to cut any kindof material. In waterjetcutting, thereis no heat generated. This is especiallyuseful for cutting tool steeland othermetals whereexcessiveheatmaychangetheproperties of thematerialWaterjet cutting does not leave a burror arough edge,and eliminatesothermachining operations such as finishsanding and grinding. It can be easilyMaterialautomatedforproductionuse

When is it Practical? The cutter is commonly connected to a high-pressure water pump, where the water is then ejected from the nozzle, cutting through the material by spraying it with the jet of high￾speed water. It’s practical to use it to cut any kind of material. In waterjet cutting, there is no heat generated. This is especially useful for cutting tool steel and other metals where excessive heat may change the properties of the material. Waterjet cutting does not leave a burr or a rough edge, and eliminates other machining operations such as finish sanding and grinding. It can be easily automated for production use