zika I-PLAS60 User Manual page 28

controller is used), scum will appear on the upper part of the workpiece on both sides of the slot.
In this condition, adjust the cutting torch or adjust the voltage slightly (not more than 5V a time)
until the scum reduces.
When the cutting speed of the cutting torch is too low and arc sprays forward, low-speed scum
will be produced. This kind of scum is a large number of bubble materials formed at the bottom
of the cut. It is easy to remove, and it can be reduced by increasing the cutting speed.
When the cutting speed of the cutting torch is too high and arc sprays backward, high-speed
scum will be produced. This kind of scum is a small number of beaded materials formed close to
the cut. It is hard to remove for it is welded at the bottom of the cut. The methods to reduce the
high-speed scum are as below.

Reduce the cutting speed.

Reduce the distance between the cutting torch and the workpiece.
Note: Sum is more easily to be produced on medium temperature or high temperature metal
when compared with low temperature metal. For example, in multi-cutting process, the least
scum will be produced during the first cutting, and the scum will increase during the cutting
afterwards with the temperature rising.
Scum is more easily to be produced on mild steel than stainless steel or aluminum.
The wear or damage of the wearing parts will cause discontinuous scum.
Flatness of the cut surface
The typical plasma cut surface appears slightly concave.
The cut surface may be more concave orconvex. Keep the cutting torch at a proper height to
ensure the flatness of the cut surface in the acceptable range. Besides, in the case that the
wearing parts are worn, the flatness of the workpiece will be affected.
If the cutting torch is too close to the workpiece, the concavity of the cut surface
will be big. Increase the distance between the cutting torch and workpiece to
improve the flatness of the cut surface.
If the cutting torch is too far away from the workpiece or the cutting current is
too high, the cut surface will appear convex. In this case, lower the cutting torch
firstly, and then reduce the cutting current.
Perforating the workpiece automatically with the cutting torch
Like the handheld cutting torch, you may start cutting with the machine-use cutting torch from
the edge of the workpiece, and you may also carry out perforation cutting. Compared with
stating arc on the edge of the workpiece, perforation cutting will shorten the lifespan of the
wearing parts.
The perforation height is generally 2.5 times the cutting height when using I-PLAS60 cutting
system. The perforation delay time should be long enough, so that the metal can be penetrated
through by arc before moving the cutting torch. However, the delay time should not be too long.
Otherwise, "arc drift" will appear when looking for the edge of the big hole. When perforating