undulating traces on the cut surface.
Make sure that the cutting torch does not contact the workpiece during cutting. Otherwise
the torch nozzle will be damaged, and the cut surface will be affected.
To understand and optimize the cutting quality
Regarding the cutting quality, the following factors should be considered.
Cutting angle – the angle at the cutting edge.
Scum – Molten material coagulated on the top and bottom surface of the workpiece.
Flatness of the cut surface – the cut surface may appear concave or convex.
The contents below explain how these factors affect the cutting quality.
Cutting angle
If the material removed from the upper part of the workpiece is more than that from the
lower part of workpiece, it is called positive angle cutting (i.e. groove cutting).
If the material removed from the lower part of the workpiece is more than that from the
upper part of workpiece, it is called negative angle cutting.
Solution
Raise the cutting torch: Increase the arc voltage if cutting torch height controller is used.
Lower the cutting torch: Reduce the arc voltage if cutting torch height controller is used.
Note: The straightest cutting angle is located on the right of the cutting torch travelling path, and
there is always a certain angle on the left. To check out whether the cutting angle problem is
caused by the plasma system or it is cause by the driving system, you can carry out cutting test
and measure the angles on both sides. Then, rotate the cutting torch by 90° inside the torch
holder, and repeat the above testing and measuring. If the angles measured are the same, it
indicates that the driving system fails. If the cutting angle problem remains after the mechanical
causes are eliminated (making sure that the cutting torch and cutting bed are correctly installed),
check the distance between the cutting torch and workpiece, especially when both of the cutting
angles are positive or negative. Besides, the workpiece material should be considered. Cutting
angle problem are more likely to happen when cuttingmagnetized or hardened metal.
Scum
When cutting with air plasma, there will always be a certain amount of scum. However, you can
adjust the system properly to reduce the amount and type of scum according to the specific
cutting application.
If cutting torch position is too low (or the arc voltage is too high when cutting torch height
