Abrasive Waterjet machining

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Abrasive Waterjet Machining
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 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 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 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
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 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
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
 Setup
 When is it Practical?
Advantages
Disadvantages
 Waterjets vs. Lasers
 Waterjets vs. EDM
 Waterjets vs. Plasma
 Waterjets vs. Other Processes
Future of Waterjet
 Drilling wells
 Drilling for oil
 Radial tunnels
Practical Applications
 Edge finishing
 Radiusing
 De-burring
 Polishing
Conclusion
 Relatively new technology has caught on quickly and is replacing century-old methods for manufacturing
 Used not only in typical machining applications, but food and soft-goods industries
 As material and pump technology advances faster cutting rates, longer component life and tighter tolerances will be achievable
 Paves the way for new machining processes that embrace simplicity and have a small environmental impact