Beveling and slag hanging are two inevitable problems when the CNC plasma cutter uses the plasma cutting method. Hanging slag is not easy to handle. How to remove the hanging slag generated by the CNC plasma cutter?
The plasma cutting arc will form irregular gaps in width, depth, and shape due to different cutting process parameters on the cutting surface of the material, which will interrupt the uniform cutting surface. At the same time, the slag is formed on the lower edge of the cutting surface. Its composition is mainly oxidation iron. This is a problem of plasma arc cut fusion.
Let's take stainless steel as an example. Due to the poor fluidity of stainless steel molten metal, it is not easy to blow away all molten metal from the incision during the cutting process. Stainless steel has poor thermal conductivity, and the bottom of the incision is easily overheated. In this way, the molten metal that has not been blown off in the incision is fused with the lower part of the incision. After cooling and solidification, it forms a so-called melt nugget or the slag. The toughness of stainless steel is good. These weld nodules are very tough and not easy to remove, which brings great difficulties in mechanical processing. Therefore, removing the fused nodules cut by the plasma arc of stainless steel is a key issue.
When cutting copper, aluminum and its alloys, due to its good thermal conductivity, the bottom of the cut is not easy to re-melt with the molten metal. Although these nodules "hang" under the incision, they are easy to remove. When using the plasma arc cutting process, the specific measures to remove the melted knob are as follows.
1.Ensure The Concentricity Of The Electrode And The Nozzle
The poor alignment of the electrode and the nozzle will cause the symmetry of the gas and the arc to be broken so that the plasma arc cannot be compressed well or the arc blows, the cutting ability is reduced, the incision is asymmetrical, causing an increase in the melt tumor. Double arcs make the cutting process impossible.
2.Ensure That The Plasma Arc Has Sufficient Power
The plasma arc power is increased, that is, the plasma arc energy is increased. The arc column is elongated so that the temperature of the molten metal during the cutting process is increased and the fluidity is good. At this time, under the action of the high-speed airflow blowing force, the molten metal is easily blown off. Increasing the power of the arc column can improve the cutting speed and the stability of the cutting process, making it possible to use larger airflow to enhance the blowing force of the airflow, which is very beneficial to eliminate the cut mat.
3.Choose the appropriate gas flow and cutting speed
If the gas flow rate is too low, the blowing force is not enough, and it is easy to produce melt. When other conditions remain unchanged, as the gas flow increases, the incision's quality is improved, and no-melt nodules can be obtained. However, the excessive gas flow rate causes the plasma arc to become shorter, making the melting ability of the plasma arc to the lower part of the workpiece worse. The dragging amount after slitting increases, and the incision is V-shaped.
The quality of the incision is mainly evaluated by the width of the incision, the verticality of the incision, the surface roughness of the incision, the depth of the cut, the bottom of the incision, and the hardness and width of the heat-affected zone of the incision. The surface quality of plasma arc cutting is between oxyacetylene cutting, and band saw cutting. When the plate's thickness is more than 100mm, due to the melting of more metal at lower cutting speed, a rough cut is often formed. The standard of a good cut is: its width is narrow, the cut's cross-section is rectangular, the cut's surface is smooth, and there is no slag. The hardness of the cut surface should not hinder the machining after cutting.