1. AIR-PLASMA CUTTING

 

• Basic process - uses an ionized gas jet (plasma) to cut material

 

• can be used on all materials that conduct electricity

 

• can be used to cut materials resistant to oxy-fuel cutting,

- stainless steel

- monel

- super-alloy plates

 

• Plasma is generated by exposing a gas stream to the electrons from an electric arc. High velocity electrons generated by the arc impact gas molecules, and ionize them.

 

 

• The gas is forced through the nozzle, and the jet heats the metal, and blasts the molten metal away.

 

 

• Advantages

- 3 to 5 times faster than conventional gas cutting

- can deal with any conducting material, including those not suited to normal gas cutting.

- stainless steels

- chromium-nickel alloys

- aluminum

- copper

- etc

- works best on ranges from .03” to 1”

- More efficient than other types of gas plasma

- can cut up to .15 m/sec continuously.

 

 

 

• Summary of Air-Plasma characteristics,

- mechanics of material removal - melting

- medium - plasma

- tool - plasma jet

- maximum temperature = 16,000C

- maximum velocity of plasma jet = 500 m/sec

- maximum mrr = 150 cm3/min

- specific energy = 1000 W/cm3/min

- power range = 2 to 200 KW

- maximum plate thickness = 200 mm (depends on material)

- cutting speed = 0.1 to 7.5 m/min

- voltage 30 to 250 V

- current <= 600 A

- critical parameters - voltage, current, electrode gap, gas flow rate, nozzle dimensions, melting temperature

- materials applications - all conducting materials

- shape application - cutting plates

- limitation - low accuracy

 

 

1.1 REFERENCES

1.2 PRACTICE PROBLEMS

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