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How to choose and use plasma source

  • Author:andy
  • Release on :2019-04-28



How to choose and use plasma source

How to choose a most suitable plasma source is extremelyimportant for cutting quality,cutting speed,cutting efficiency.
1.Cutting current: It decides cutting thickness and speed---cutting ability.
Effects
1)When enlarge it, arc energy increases,cutting ability increases;
2) When enlarge it, arc diameter increases,kerf becomes wide;
3)If cutting current is too large,nozzle thermal load increases, nozzle willdamage, cutting quality will decline. Thus before cutting, we should chooseproper cutting current and nozzles according to plate thickness.

2. Cutting speed: Best speed should depends on its handbook. Regardingto different thickness, material, melting point, thermal conductivity andsurface tension after melting, there is different cutting speed. Mainmanifestation
1) Increase cutting speed moderately can improve cutting quality----cuttingedge will be narrrow and more flat and reduce heat distortion.
2)If speed too fast, heat input will be underrequired value, jet flow can notblow offmelting fusant, thus to form large and dross, cutting edge not smooth.
3) If speed too slow, kerf will be large, arc will even die out.
So, cutting speed is very important for good cutting quality.

3.Arc voltage: Usually output voltage is cuttingvoltage.Plasma power source usually has very high open circuit voltage&working volt. When use nitrogen, hydrogen or air,required voltage will behigher.When currenct is fixed,rise of voltage means rise of enthalpy andcutting ability.If at the same time,you reduce jet diameter and increase airflow rates,you will get faster cutting speed and better cutting quality.

4.Working gas and flow rates: Working gas includes cutting gas and process gas,some equipement require arcing gas. We need to choose proper gas according tomaterial, thickness and cutting mode. Cutting gas should not only assure theformation of plasma arc jet, but also blow off dross and oxide in the kerf. Toolarge air flow will take away more arc energy,which will shorten jet length andreduce cutting ability and cause unstability of the arc. Too small air flowwill weaken straightness of plasma arc and thus reduce the cutting depth,causedross.
So, air flow should coordinate with cutting current.

Present plasma power source apply air pressure to control airflow,because when diameter of cutting nozzle is fixed, air flow  depends on airpressure.To cut certain  thickness,we need to choose proper air pressureaccording to data provided by suppliers. Usual working gas including: oxygen,nitrogen, hydrogen, argon or air and H35 mixed gas of argon nitrogen and soon.