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One: When the CNC plasma cutting machine is divided into multiple cutting auxiliary gases, the cutting speed of different cutting gases is different. Taking air plasma arc cutting as an example, when cutting carbon steel, the cutting current is 230A. As a standard, the cutting speed of 6mm thick carbon steel plate can reach 3300mm/min. When the thickness is adjusted to 40mm, the cutting speed is limited to 500mm/min to ensure the cutting effect and quality. If you switch to other auxiliary cutting gases, such as cutting with pure oxygen, the cutting speed will decrease even more. Under the same cutting current of 230A, although pure oxygen plasma cutting can be increased to 3700mm/min, for 6mm thick carbon steel plate, the cutting speed is only 350mm/min for 40mm carbon steel plate.

Two: There are many factors that affect the quality of plasma cutting, such as no-load voltage and arc column voltage, cutting current, electrode shrinkage, cutting nozzle height and other plasma arc cutting technical parameters, which will directly affect the cutting stability process of CNC plasma cutting machine. Cut quality and functionality. Generally speaking, factors such as no-load voltage and arc column voltage, cutting current size, electrode shrinkage rate, cutting nozzle height and other factors directly affect the fastening effect of the plasma arc, that is, the temperature and energy density of the plasma arc and the high temperature and high energy of the plasma arc. The cutting speed is determined, so it can be said that many of the above factors are basically related to the cutting speed. As a CNC cutting device, the cutting speed should be increased as much as possible while ensuring the cutting quality. This not only increases productivity, but also reduces the amount of deformation of the cut section and the heat-affected zone of the grooved area. If the cutting speed is not right, it will have the opposite effect, add paste residue, reduce the quality of the cut, and set the small details above the CNC cutter.

The parameters of the CNC plasma cutting machine are set as follows:

The radial direction of the jet transfers more heat, so the incision is widened, and the molten material on both sides of the incision gathers and solidifies at the bottom edge, forming slag that is not easy to clean, and the upper edge of the incision is rounded due to excessive heating and melting.

Increase, the cutting capacity increases, and the cutting speed increases accordingly;

1. The cutting current increases, the arc diameter increases, and the arc thickens to make the incision wider;
2. Excessive cutting current increases the thermal load of the nozzle, the nozzle is damaged prematurely, and the cutting quality naturally declines, and even normal cutting cannot be performed. Therefore, the cutting current and the corresponding nozzle should be correctly selected according to the thickness of the material before cutting.
3. Nozzle height:

Refers to the distance between the nozzle end face and the cutting surface, which forms part of the entire arc length. Since plasma arc cutting generally uses a power supply with constant current or steep drop characteristics, after the nozzle height increases, the current changes very little, but it will increase the arc length and cause the arc voltage to increase, thereby increasing the arc power; but at the same time, it will also make The arc length exposed to the environment increases, and the energy lost by the arc column increases. In the case of the combined effect of the two factors, the effect of the former is often completely offset by the latter, which will reduce the effective cutting energy and reduce the cutting ability. Usually, the blowing force of the cutting jet is weakened, the slag remaining in the lower part of the incision increases, and the upper edge is over-melted and rounded corners appear. In addition, considering the shape of the plasma jet, the diameter of the jet expands outward after leaving the muzzle, and the increase in the height of the nozzle will inevitably lead to an increase in the width of the incision. Therefore, it is beneficial to choose the nozzle height as small as possible to improve the cutting speed and cutting quality. However, when the nozzle height is too low, it may cause double arc phenomenon. Using a ceramic outer nozzle can set the nozzle height to zero, that is, the end face of the nozzle directly contacts the surface to be cut, and good results can be obtained.

7. Cutting current:

Cutting current is the most important cutting process parameter, which directly determines the thickness and speed of cutting, that is, cutting ability. Affect:

1. Cutting current increases, arc energy
2. Arc voltage:

It is generally considered that the normal output voltage of the power supply is the cutting voltage. Plasma arc cutting machines usually have higher no-load voltage and working voltage, and when using gases with high ionization energy such as nitrogen, hydrogen or air, the voltage required to stabilize the plasma arc will be higher. When the current is constant, the increase of the voltage means the increase of the arc enthalpy and the improvement of the cutting ability. If the diameter of the jet is reduced and the flow rate of the gas is increased while the enthalpy value is increased, a faster cutting speed and better cutting quality can often be obtained.

5. Cutting speed:

The optimum cutting speed range can be selected according to the equipment instructions or determined by experiments. Due to the thickness of the material, different materials, melting point, thermal conductivity and surface tension after melting, the cutting speed also changes accordingly.

4. When the speed is extremely low:

The arc may even be extinguished due to the wide cut. It can be seen that good cutting quality and cutting speed are inseparable.

3. When the cutting speed is too low:

Since the cutting place is the anode of the plasma arc, in order to maintain the stability of the arc itself, the anode spot or anode area must find a place for conducting current near the cutting slot closest to the arc, and at the same time, it will conduct current to the arc.

2. When the cutting speed is too fast:

If the cutting line energy is lower than the required value, the jet in the slit cannot quickly blow off the molten cutting melt immediately, resulting in a large amount of back drag. Along with the slag hanging on the incision, the surface quality of the incision decreases.

1. The cutting speed should be moderate

A moderate increase in cutting speed can improve the quality of the incision, that is, the incision is slightly narrowed, the surface of the incision is smoother, and the deformation can be reduced.

The biggest advantage of the plasma cutting machine application field over the traditional gas cutting processing method is to make up for the use demand of non-carbon steel materials. From the current domestic plasma cutting machine application technology, the cutting processing of high hardness materials such as stainless steel still mainly adopts the plasma cutting method. , which has also largely promoted the rapid development and market popularization of plasma cutting machine equipment in my country in recent years.

 

When CNC plasma cutting machine processes stainless steel materials, several important cutting configuration parameters are cutting speed and input current. Generally, we recommend users to adjust the relevant parameter design according to the equipment configuration table provided by the manufacturer to achieve the best performance. However, in the actual production process, it may be necessary to adjust the above parameters appropriately due to the shift of the emphasis on production efficiency or processing quality. To this end, Wuhan Jiabeide Technology will make an in-depth analysis of the influence of the input current and cutting speed of the CNC plasma cutting machine.

 

1. Cutting speed of stainless steel plasma cutting machine
2. The optimal cutting speed range can be selected according to the equipment instructions or determined by experiments. Due to the thickness of the material, different materials, melting point, thermal conductivity and surface tension after melting, the cutting speed also changes accordingly. . main performance:
3. When the cutting speed is too low, since the cutting place is the anode of the plasma arc, in order to maintain the stability of the arc itself, the anode spot or anode area must find a place for conducting current near the cutting seam closest to the arc, and at the same time, it will send the current to the jet. More heat is transmitted in the radial direction, so the incision is widened, and the molten material on both sides of the incision gathers and solidifies at the bottom edge, forming slag that is not easy to clean, and the upper edge of the incision is rounded due to excessive heating and melting.
4. When the speed is extremely low, the arc will even be extinguished due to the excessively wide cut. It can be seen that good cutting quality and cutting speed are inseparable.
5. A moderate increase in the cutting speed can improve the quality of the incision, that is, the incision is slightly narrowed, the surface of the incision is smoother, and the deformation can be reduced.
6. The cutting speed is too fast, so that the cutting line energy is lower than the required value, and the jet in the slit cannot quickly blow off the molten cutting melt and form a large amount of back drag. Surface quality declines.

 

2. Cutting current of stainless steel plasma cutting machine

It is the most important cutting process parameter of CNC plasma cutting machine, which directly determines the thickness and speed of cutting, that is, cutting ability. Affect:

1. The cutting current increases, the arc energy increases, the cutting ability increases, and the cutting speed increases accordingly;
2. If the cutting current is too large, the thermal load of the nozzle will increase, the nozzle will be damaged prematurely, and the cutting quality will naturally decline, and even normal cutting cannot be performed. Therefore, the cutting current and the corresponding nozzle should be correctly selected according to the thickness of the material before cutting.
3. The cutting current increases, the arc diameter increases, and the arc becomes thicker to make the incision wider.