What Is A Plasma Cutter?
A plasma cutter is a power tool that uses plasma cutting technology to melt and evaporate the incision of the metal workpiece by using the heat of the plasma arc with argon, hydrogen, nitrogen, oxygen, air, water vapor and some mixed gases to form an incision.
How Does A Plasma Cutter Work?
Plasma cutters have a variety of shapes and sizes. There are large format CNC plasma cutting tables that use robotic arms to control precise cutting, and there are also streamlined handheld plasma cutters used in hand workshops. Regardless of the size, all plasma cutters are based on the same principle, and the structural design is roughly the same. When the plasma cutting machine is working, it sends out compressed gas such as nitrogen, argon or oxygen through a narrow pipe. A negative electrode is placed in the middle of the pipe. When power is supplied to the negative electrode and the nozzle opening contacts the metal, a conductive loop is formed, and a high-energy electric spark is generated between the electrode and the metal. As the inert gas flows through the pipeline, the electric spark heats the gas until it reaches the fourth state of matter. This reaction process produces a plasma stream with a temperature of about 16,649 degrees Celsius and a flow rate of 6,096 meters per second, which can quickly turn the metal into slag. Electric current flows through the plasma itself. As long as the electrode is continuously powered and the plasma is in contact with the metal, the arc generation cycle is continuous. In order to ensure this contact while avoiding damage caused by oxidation and other unknowable characteristics of the plasma, the cutting machine nozzle is equipped with another set of pipes. This group of pipes continuously emit protective gas to protect the cutting area. The pressure of the shielding gas can effectively control the radius of the columnar plasma. The installation location of the plasma cutter should be far away from large-scale electrical equipment and places with frequent electrical interference.
What Is A Plasma Cutter Used For?
The plasma cutting machines can cut carbon steel, stainless steel, iron, aluminum, copper, titanium, nickel and other metal materials, and are widely used in locomotives, automobiles, pressure vessels, engineering machinery, nuclear industry, general machinery, ships, aviation, steel structures and other industries.
How To Set Up A CNC Plasma Cutter?
In the daily production process, the use of plasma cutters will cause a lot of dust, so we must install strong ventilation devices in the equipment workplace to exhaust the smoke generated during the cutting process of CNC plasma cutters. Before powering on the equipment, check that all the switches on the equipment are in the off position and the rotary switch at the rear of the plasma power supply is in the horizontal position.
1. Turn on the power supply of the main power switch cabinet to make the two cables have power.
2. Turn the circuit breaker in the control box of the machine to the ON position.
3. Turn on the power supply of CNC controller with the key switch, and the main interface should appear on the display.
4. Turn the rotary switch on the back of the plasma power supply by 90° to the vertical position. At this time, the power indicator on the front of the plasma power supply should be on.
5. Turn on the air compressor (compressor flow rate 1m3/min), adjust the air compressor pressure control switch, so that the compressor output air pressure is between 6.1-8.2 Bar; if the air pressure is lower than 6.1 Bar, the air pressure will be reduced during cutting, thereby improving the cutting quality Unstable; if the air pressure is higher than 8.3Bar, it will damage the air filter on the plasma power supply. Adjust the air pressure adjustment knob on the plasma power supply to keep the pressure at 5.5-6.0 Bar. Rotate the plasma power supply current adjustment/gas test knob to the gas test position to confirm that the air pressure will not drop below 5 Bar. When the pressure is lower than 5Bar, the cutting quality will be seriously affected, and even the plasma power supply will stop working.
If the working environment cannot guarantee the cleanliness of the supply air source, a multi-stage combined filtration system should be installed in front of the plasma power source. Otherwise, the air containing oil, moisture, and dust will cause serious consequences such as arcing failure and damage to the cutting torch during cutting.
If plasma cutting is used, the start-up preparation has been completed.
How To Use A Plasma Cutter Correctly?
Whether you are a beginner or a CNC machinist, you must follow the 7 tips to operate the plasma cutting machine.
1. Place the plate to be cut in a suitable position on the worktable, and the plate cannot touch the track.
2. Compile the program according to the drawing or software, and cut the empty car if necessary, and check whether the programming is accurate.
3. When cutting, start the plasma cutter first, find the entry point, adjust the cutting parameters, turn on the air source, start the plasma cutter, and enter the program to control cutting.
4. When cutting, it is strictly forbidden to stand on the cut plate and rack rail, and do not disturb the electrical components and transmission components.
5. Always keep the transmission rack, guide rail and transmission steel belt clean to ensure operation accuracy.
6. Special attention should be paid to the cleaning and maintenance of the control console, and the processing and programming should be carried out under the guidance and assistance of professional and technical personnel.
7. When using cranes to lift plates, strictly abide by the safety technical operating regulations for crane operations and ground (hook) operations, and cooperate closely.
What Should I Pay Attention To When Using A Plasma Cutter?
During operating, clean the dust in the cutting machine and the dirt on the components regularly, and check whether the wires are aging or not. Poor contact between the ground wire and the workpiece. Grounding is an indispensable preparation before cutting. If a dedicated grounding tool is not used, insulation on the surface of the workpiece and long-term use of a ground wire with serious aging, etc., will cause poor contact between the ground wire and the workpiece. Special grounding tools should be used, and check whether there is any insulation affecting the grounding wire and the surface of the workpiece, and avoid using aging grounding wires. When the spark generator cannot automatically cut off the arc, the plasma cutting machine must first ignite the plasma arc. The high-frequency oscillator excites the gas between the electrode and the inner wall of the nozzle to generate a high-frequency discharge to partially ionize the gas to form a small arc. A small arc is subjected to the action of compressed air and ejected from the nozzle to ignite the plasma arc, which is the main task of the spark generator.
1. To ensure the correct gas pressure and flow of plasma. The correct gas pressure and flow of plasma are very important to the service life of consumable parts. If the air pressure is too high, the life of the electrode will be greatly reduced; if the air pressure is too low, the life of the nozzle will be affected.
2. Use a reasonable cutting distance. According to the requirements of the instruction manual, use a reasonable cutting distance. The cutting distance is the distance between the cutting nozzle and the surface of the workpiece. When perforating, try to use twice the normal cutting distance or use the plasma arc to transmit. The maximum height.
3. The thickness of the perforation should be within the allowable range of the machine system. The plasma cutter cannot perforate the steel plate that exceeds the working thickness. The usual perforation thickness is 1/2 of the normal cutting thickness.
4. Do not overload the nozzle. If the nozzle is overloaded (that is, the working current of the nozzle is exceeded), the nozzle will be damaged quickly. The current intensity should be 95% of the working current of the nozzle. For example: the current intensity of a 100A nozzle should be set to 95A.
5. Keep the plasma gas dry and clean. The plasma system needs dry and clean plasma gas to work properly. Dirty gas is usually a problem in the gas compression system, which shortens the service life of consumable parts and causes abnormal damage. The method to test the gas quality is to set the cutting torch in the test state, and place a mirror under it to consume the gas in the cutting torch. If water vapor and mist appear on the mirror, you need to find out the reason and correct it.
6. Plasma cutting should start from the edge as much as possible, instead of perforating cutting. Using the edge as the starting point will extend the life of the consumable parts. The correct method is to directly aim the nozzle at the edge of the workpiece before starting the plasma arc.
7. Avoid the extension and extension of the plasma arc. If the plasma arc can only be extended and extended to contact the surface of the workpiece, the plasma arc will produce such extension and extension at the beginning and end of cutting, which will cause abnormal damage to the nozzle. This problem can be avoided if the correct edge start technique is used and the appropriate "arc breaking" signal time is selected.
8. Reduce unnecessary "arc starting (or arc guiding)" time. The nozzle and electrode are consumed very quickly when starting the arc. Before starting, the cutting torch should be placed within the walking distance of cutting metal.
9. Applying splash-proof chemical coating on the protective shell Splash-proof chemical coating helps to reduce the accumulation of slag on the protective shell. But be sure to remove the protective shell from the torch before applying splash-proof paint.
10. Remove the slag on the protective shell.