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”