HGG SPC 1000, Руководство оператора, Страница: 96 / 169

Calibration
Plasma cutting
When cutting with plasma the first test piece to correct the oscillation of the torch is exactly the same as
described for oxyfuel. Make sure you choose the plasma torch when selecting the cutting process. You will
see that there is now only one choice of test piece. Cut the test piece as descibed in the previous section.
The remaining deviations can be evaluated and corrected by cutting a series of rings from the pipe. The
ring is formed by cutting two chamfers a small distance apart. The first chamfer will be used to assess
the angle of the beam relative to the material. By cutting a chamfer with a default slope (90°), the cut
should be perpendicular to the outer wall of the pipe. When cutting with plasma it is important that the
side of the plasma beam adjacent to the part is accurate and correct. The opposite side of the beam will
be on the scrap or waste side of the cut and is unimportant to the accuracy of the finished part.
It is therefore important to understand the factors that influence and affect the quality of plasma cutting
so that the test pieces can be correctly evaluated. This section describes in detail the causes of the
deviations that will be corrected by cutting and evaluating the rings that are to be cut from the pipe.
Cutting direction
The cutting direction is important. The right hand side of the cut (relative to the forward motion of
the torch) is always the ‘good’ side. Depending on the cut, this can mean that the cutting direction is
clockwise or anti-clockwise. The ‘part’ should always be on the right hand side of the plasma arc, the
‘scrap’ always on the left hand side. When cutting holes or slots the ‘good’ side is always on the outside
of the hole, the inside is the the circle being cut out, the scrap side.
Cut angle
This refers to the angularity of the cut itself. A ‘positive’ cut angle occurs when more material is removed
from the top of the cut than the bottom. A ‘negative’ cut angle occurs when more material is removed
from the bottom. Don’t forget that the right hand side must be straight, the left hand side (scrap side)
will always have a degree of angularity but this is not important to the quality.
A cut angle problem can also be caused bij misalignment of the torch. To check whether it is the plasma
system or a mechanical problem, make a test cut and measure the angles. Rotate the torch 90° in its
holder and repeat the cut. Measure the angles again. If the angles are the same on both tests then it is
a mechanical alignment problem. If the angles are all positive or all negative it can be corrected with an
angle correction in the settings.
CALIBRATION
Positive cut angle Negative cut angle Part Scrap Scrap