DPM NC1530 Portable Plasma Cutting Machine is heated to a very high temperature and highly ionized gas, it will transfer the arc power to the workpiece, the high heat will melt the workpiece and be blown off, forming the working state of plasma arc cutting, using the momentum of high speed plasma to expel the molten metal to form an incision processing method.Below Fang Shengyun to give you a popularization of the basic principles of CNC Plasma Cutting Machine.
Introduction to the
Plasma Cutting Machine with different working gas can cut all kinds of oxygen cutting difficult to cut metal, especially for non-ferrous metals (stainless steel, aluminum, copper, titanium, nickel) cutting effect is better;Its main advantage is that the thickness of the metal cutting, plasma cutting speed is fast, especially in the cutting of ordinary carbon steel sheet, the speed can reach 5~6 times of oxygen cutting method, cutting surface smooth, small thermal deformation, almost no heat affected zone!Plasma cutting machine is widely used in automobiles, locomotives, pressure vessels, chemical machinery, nuclear industry, general machinery, construction machinery, steel structure and other industries.
Operating principle flow
After the compressed air enters the cutting torch, it is divided into two ways by the gas chamber, that is, forming plasma gas and auxiliary gas.Plasma arcs to melt the metal, while auxiliary gases cool parts of the torch and blow away melted metal.
The cutting power supply includes the main circuit and the control circuit. The electrical principle: the main circuit includes contactor, three-phase power transformer with high leakage reactance, three-phase bridge rectifier, high-frequency arc coil and protection element.The external characteristics of the power source from high leakage reactance to steep.The control circuit completes the whole cutting process through the button switch on the cutting torch: pre-aeration - main circuit power supply - high frequency arc initiation - cutting process - stop arc.
The power supply of the main circuit is controlled by contactor;The air flow is controlled by solenoid valve;The high frequency oscillator is controlled by a control circuit to ignite the arc, and the high frequency stops working after the arc is established.
Plasma arc cutting process parameters
Various plasma arc cutting parameters directly affect the stability, quality and effect of the cutting process.The main cutting specifications are briefly described as follows:
1.No-load voltage and arc column voltage
The plasma cutting power supply must have a high enough no-load voltage in order to initiate arc easily and make plasma arc stable combustion.The no-load voltage is generally 120-600V, while the arc column voltage is generally half of the no-load voltage.By increasing arc column voltage, the power of plasma arc can be increased obviously, and thus the cutting speed and thickness of sheet metal can be improved.The arc column voltage is often not reached by adjusting the gas flow rate and increasing the electrode shrinkage, but the arc column voltage cannot exceed 65% of the no-load voltage, otherwise it will make the plasma arc unstable.
Increasing the cutting current can also increase the power of plasma arc, but it is limited by the maximum allowable current, otherwise the plasma arc column will become thicker, the slit width will increase, and the electrode life will decrease.
Increasing the gas flow can not only improve the arc column voltage, but also enhance the compression action of the arc column, so that the plasma arc energy is more concentrated and the jet force is stronger, so that the cutting speed and quality can be improved.However, if the gas flow is too large, the arc column will become shorter, the heat loss will increase, and the cutting ability will be weakened, until the cutting process cannot be carried out normally.
4.Internal shrinkage of electrode
The so-called internal shrinkage refers to the distance between the electrode and the end face of the cutting nozzle. The appropriate distance can make the arc get good compression in the cutting nozzle and obtain the plasma arc with concentrated energy and high temperature for effective cutting.If the distance is too large or too small, the electrode will be seriously burned, the cutting nozzle will be burned and the cutting ability will be reduced.The internal shrinkage is generally 8-11mm.
5.Cutting nozzle height
The height of the cutting nozzle refers to the distance between the end face of the cutting nozzle and the surface of the workpiece to be cut.The distance is generally 4~10mm.It is the same as the electrode shrinkage, the plasma arc cutting efficiency should be given full play to the distance, otherwise the cutting efficiency and cutting quality will be reduced or the cutting nozzle will be burned.
All the above factors directly affect the compression effect of plasma arc, that is, the temperature and energy density of plasma arc, and the high temperature and high energy of plasma arc determine the cutting speed, so all the above factors are related to the cutting speed.On the premise of ensuring cutting quality, cutting speed should be increased as much as possible.This not only improves the productivity, but also reduces the deformation of the cut part and the heat affected area of the slit area.If the cutting speed is not appropriate, its effect is opposite, and will make the adhesive slag increase, cutting quality decline.
Nc plasma cutting machine in use to master some attention to detail, otherwise easy to cut because of the quality of instability, wear parts frequently replaced and failure.So small CNC plasma cutting machine at ordinary times what are the skills?
1, CNC plasma cutting machine to use a reasonable cutting distance
According to the requirements of the manual, a reasonable cutting distance, that is, the distance between the cutting nozzle and the workpiece surface, when perforating, as far as possible to use two times the normal cutting distance or the maximum height of plasma arc can be transferred.
2, CNC plasma cutting machine cutting should start from the edge
A small CNC plasma cutter should try to cut from the edge rather than through a hole.The starting point of the small CNC plasma cutting machine will prolong the service life of the consumable parts, so the correct method is to point the nozzle directly at the edge of the workpiece before starting the plasma arc.
3, CNC plasma cutting machine to reduce the unnecessary "arc (or guide arc)" time
When arc starting, the consumption of nozzle and electrode is very fast, so before starting, the cutting torch should be placed within the walking distance of cutting metal.
4, CNC plasma cutting machine to keep cutting torch and consumable parts clean
Any dirt on the cutting torch and consumables will greatly affect the function of the plasma system.When replacing consumable parts, put them on clean floriferous cloth, always check the connecting rib of the cutting torch, and clean the electrode contact surface and nozzle with hydrogen peroxide cleaning agent.
5, CNC plasma cutting machine nozzle can not overload use
Overloading the nozzle (that is, exceeding the working current of the nozzle) will cause the nozzle to damage faster.The current intensity should be 95% of the working current of the nozzle.For example, the current intensity of 100A nozzle should be set to 95A.
6. The perforation thickness of CNC plasma cutting machine should be within the permissible range of the machine system
The small CNC plasma cutting machine shall not perforate the steel plate which exceeds the working thickness. The general perforation thickness is 1/2 of the normal cutting thickness.
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