Principle of plasma cutting
The principle of plasma laser cutting is: arc discharge is performed between the base material (including the nozzle in the cutting torch) and the electrode in the cutting torch, and the thermal energy of the discharge is used to generate a high-temperature, high-speed plasma arc of the compressed gas, and the cutting method of the base material is fused.
Features of Air Plasma Cutting: Easy to cut all metals, fast cutting speed
Less cutting deformation, cutting can be achieved without fixing fixtures. Cutting shape is not limited. Small heat affected part
Both contact and non-contact cutting are possible.
Widely used in industrial production, especially for the welding of machining copper and copper alloys, titanium and titanium alloys, alloy steel, stainless steel, molybdenum and other metals used in military and advanced industrial technologies such as aerospace, such as titanium alloy missile shells and spacecraft Some thin-walled containers etc.
Type of plasma arc
There are three types of plasma arcs: non-transfer type, transfer type and combined type according to the power connection.
(1) Non-transfer plasma arc tungsten electrode is connected to the negative end of the power source, and the nozzle is connected to the positive end of the power source. The plasma arc body is generated between the tungsten electrode and the nozzle. Under the pressure of the plasma gas, the arc column is ejected from the nozzle to form a plasma. flame.
(2) Transfer type plasma arc The tungsten electrode is connected to the negative terminal of the current and the weldment is connected to the positive terminal of the current. The plasma arc is generated between the tungsten electrode and the weldment. Because the transfer arc can transfer more heat to the weldment, almost all metal welding and cutting use transfer plasma arc.
(3) Combined plasma arc Non-transferred arc and transferred arc coexist at the same time, so it is called combined plasma arc. The non-transferred arc plays the role of stabilizing the arc and supplementary heating. The transfer arc directly heats the weldment, melting it for welding. Mainly used for micro-beam plasma arc wire edm welding and powder surfacing.
Transfer plasma arc
In order to establish a transfer type plasma arc, the tungsten electrode should be connected to the negative electrode of the power supply, and the nozzle and the weldment should be connected to the positive electrode at the same time. The transfer type arc first connects the circuit between the tungsten electrode and the nozzle, ignites the arc between the tungsten electrode and the nozzle, and Quickly switch on the circuit between the tungsten electrode and the weldment, so that the arc is transferred to the tungsten electrode and the weldment to burn directly, and at the same time cut off the circuit between the tungsten electrode and the nozzle
Under normal working conditions, the nozzle is not charged, and the plasma arc generated at the beginning of ignition is only used as an intermediate medium for establishing the transfer arc.