36
CUT QUALITY
The plasma process cuts by melting the material and
therefore a characteristic feature is the greater degree
of melting towards the top of the metal resulting in
poor edge squareness, top edge rounding or a bevel
on the cut edge.
Cut quality can often depend on setup and your
application parameters with torch height, cutting
speeds, compressed air pressures along with the
users abilities to maintain these during the cutting
process.
To help understand cut quality, it is best that the
characteristics of the finished cut are looked at in
close detail, the image adjacent will help explain this.
Cutting or torch angle
Generally when cutting with a plasma torch, the torch should be held perpendicular to the piece being
cut.
Stand off distance
The distance between the torch tip and the work piece during the cutting process will have an effect on
the bevel angles. The greater the distance, the greater the bevel angle will be. Typically, smaller hand
cutting systems (usually 40 amps and under) are designed to drag the tip on the plate.
For higher amperage hand cutting systems, use of a drag shield cup, a standoff guide or a cutting guide
will help keep a consistent tip to work distance for best results.
Kerf width
While plasma cutting a void is left behind which is called the kerf in the material being cut.
Bevel angle
In an ideal cut, the bevel angle or angle of the cut surface would be perfectly square.
The plasma cutting process does result in a slight angle which is called a bevel angle, on both the cut and
scrap side of the work piece. This is why direction of cut is important. When the plasma gas flows, it has
a swirling action as it leaves the cutting tip
’
s orifice. This swirl is generally in a clockwise direction which
results in one side of the material being cut being squarer than the other. This means it is very important
to consider the travel direction in relation to the piece being cut.
In the image adjacent, a circle shaped object is being cut.
The inside cut (A) is done in the anti
-
clockwise
direction and the outside cut (B) is done in
a clockwise direction.
So remember, if you are making a circular
cut and plan to keep the inside round piece as
your finished work, move in a clockwise direction.
If you plan to keep the piece from which the circle
was cut from then move in an anti
-
clockwise direction.
The Jasic EVO range of plasma machines offer
optional circle cutting guide kits to assist with circle cutting.
Summary of Contents for EVO 2.0 EP-45
Page 1: ...1 ClearVision Optional TFT LCD screen included...
Page 44: ...44 UKCA Declaration of Conformity...
Page 45: ...45 EC DECLARATION OF CONFORMITY...
Page 50: ...50...