How to make cnc plasma cutting machine cutting clean without incision slag

The plasma cutting machine will break the uniform cutting surface because of the different cutting parameters, such as width, depth and irregular shape. At the same time, hanging slag will be formed at the lower edge of the cutting surface. Its main component is iron oxide. This is the problem of plasma arc welding and how to eliminate these problems.

We take stainless steel as an example, because of the poor fluidity of stainless steel molten metal, it is not easy to blow all the molten metal from the incision during cutting. Stainless steel has poor thermal conductivity and is easy to overheat at the bottom of the notch, so that the residual melted metal in the notch is not blown off, and the lower part of the notch is melted into one body. After cooling and solidification, the so-called melt or hanging slag is formed. The toughness of stainless steel is good, these melts are very tough, it is not easy to remove, bring great difficulties to the machining. Therefore, removal of molten metal from stainless steel plasma arc cutting is a key problem.

When cutting copper, aluminum and its alloys by plasma cutting machine, the bottom of the incision is not easy to fuse with the molten metal because of its good thermal conductivity. These fused tumors are "hanging" under the incision, but they are easy to remove.

In the process of plasma arc cutting, the specific measures to remove the fusion are as follows.

1. Ensure the concentricity of the tungsten electrode and the nozzle of the plasma cutting machine. If the tungsten electrode is not well aligned with the nozzle, the symmetry of gas and arc will be destroyed, so that plasma arc can not be well compressed or produced arc bias blowing, cutting ability will be reduced, incision is asymmetrical, resulting in the increase of melt, serious double arc, so that the cutting process can not proceed smoothly.

2. Ensure plasma arc plasma arc has enough power. The increase of plasma arc power, i.e. the increase of plasma arc energy and the elongation of arc column, makes the temperature and fluidity of the melted metal increase during cutting process. At this time, the melted metal is easy to be blown off under the action of high-speed airflow. Increasing the arc column power can improve the cutting speed and the stability of the cutting process, making it possible to use a larger air flow to enhance the air blowing force, which is very beneficial to eliminate the incision melt.

3. Choose the appropriate gas flow rate and cutting speed of plasma cutting machine. The gas flow rate is too small and the blow force is not enough. When other conditions remain unchanged, with the increase of gas flow rate, the quality of the incision is improved and the non-melting incision can be obtained. However, excessive gas flow leads to shorter plasma arc, worse melting ability of plasma arc on the lower part of the workpiece, increased drag after slotting, V-shaped incision, but easy to form a melt.

The quality of the incision was mainly evaluated by the width of the incision, the perpendicularity of the incision, the surface roughness of the incision, the depth of the incision, the hardness and width of the incision bottom melt and the heat affected zone. The surface quality of plasma arc cutting is between oxygen-acetylene cutting and band saw cutting. When the thickness of the plate is over 100 mm, the metal melts more at a lower cutting speed, and a rough cut is often formed.

The standard of good incision of plasma cutting machine is: narrow width, rectangular cross-section of incision, smooth surface of incision, no slag or hanging slag, the surface hardness of incision should not hinder the machining after cutting.