1. HIGH PRESSURE JET CUTTING
• Typical jet size <0.8mm faster than speed of sound.
• Typical fluid is water.
• Good for slotting.
• Used on,
- metals
- paper
- cloth
- wood
- leather
- rubber
- plastics
- frozen food
- ceramics
• Main divisions or use,
- jet cutting
- destruction of brittle materials
- separation of materials
• Typical pressures are 150-1000 MPa and use 8-80 KW.
• Velocities are 540-1400 m/s.
• Typical fluid volume is 0.5 to 2.5 l/min.
• Fluid Pressure Intensifier - hydraulics actuates smaller cylinders, that drive larger cylinders. The larger cylinders intensify air pressure.
• Nozzle - internal diameter reduces 40 to 160 times to the exit tip.
• The exit jet looks like,
• Cutting - If the material is brittle it will fracture, if ductile or erosive, it will cut well.
• Pulsed cuts can cut deeper, but feed rates must be reduced for acceptable cuts.
• The fluid used must have a low viscosity to minimize energy loses,
- be non-corrosive
- non-toxic
- common and inexpensive
• Water most common, but additives such as alcohols, oils, products and glycerol are used, when they can be dissolved in water (ventilation may be required).
• The typical head is shown below. The orifice is often made of sapphire and ranges from 0.05” to 0.020”