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vertical and horizontal blow force of the arc is formed, the vertical one helps to
blow away the molten metal, while the horizontal one makes the molten metal
flow backward along with incision bottom, this over-heated metal will melt
parts of the bottom metal again, then the burr is formed when they cool down
and melt together.
The burr is caused by overheat bottom. When the cutting speed is too slow, but
the incision bottom is so over-heated that it melts, the liquid metal flows to
bottom metal and combines into one which makes the difficulty to blow away
molten metal by air current, and then the burr is formed.
The air current blow force is not enough. When cutting with plasma, the arc
blow force consists of the air current blow force and the arc electromagnetic
force, the air current blow force acts the main function. If the air current blow
force is not strong enough, it cannot ensure all the burr is flown away, then the
burr is formed.
3)
The measurement to eliminate burr
Ensure the centering between electrode and nozzle precisely, so that the
compression of the plasma arc is not damaged, the concentration of flame and
cutting capacity can be guaranteed.
Enough power to ensure the fluidity of molten metal, as well as increase the
stability of the cutting speed and operation. This makes it possible to adopt
large air flux to enlarge the air blow force, and beneficial for eliminating burr.
Adjust suitable air flow and cutting speed. If the air flow is too small, the blow
force is not enough, while if too big, the plasma arc will be shorten, the incision
will be “V” shape, the drag enlarge. The burr can be formed under both
conditions.
When cutting speed is too slow, the incision is large and rough, the bottom is
easy to be over-heated, while the cutting speed is fast, the drag is enlarged, this
is not beneficial for eliminating burr.
So under certain circumstance, there exists a proper selection range for air flow
and cutting speed.
4)
Diminish the cutting surface slanting and rounding issue
The incision surface is a little slant and the upper side is a little round during cutting
with air plasma. Though the slanting range is acceptable during the cutting process, in
order to improve the cutting quality, people begins to pay attention to this problem.
Usually slowing down the cutting speed properly can avoid the slanting, but this may
enlarge the effect zone and incision width, as well as decrease the production
