What is a CNC plasma table?
Desktop plasma cutting machine is a high-efficiency, high-precision, and high-reliability thermal cutting equipment that combines computer control, precision mechanical transmission, and plasma cutting technologies.
CNC plasma table machine, including flat plasma cutting machine, plate and tube integrated plasma cutting machine, square tube plasma cutting machine. The reinforced bed makes the equipment more stable during operation, compared with portable plasma cutting machine and gantry plasma cutting machine, desktop plasma cutting machine has the advantages of fast speed and high precision, and is more suitable for batch processing of medium and thin plates.
How to use CNC plasma table machine?
- Ensuring the correct pressure and flow of the plasma. The correct pressure and flow of the plasma are very important to the service life of the consumables. If the pressure is too high, the life of the electrode will be greatly reduced; if the pressure is too low, the life of the nozzle will be affected.
- Use a reasonable cutting distance. According to the details of the requirements, choose an available cutting distance, which is the distance between the workpiece surface and the cutting nozzle. When perforating, try to use 2 times the normal cutting distance or use the plasma arc to transmit The maximum height.
- The thickness of the perforation should be within the allowable range of the machine system. The plasma cutting machine cannot perforate the steel plate that exceeds the working thickness. The usual perforation thickness is 112 of the normal cutting thickness.
- Do not overload the nozzle. Use to overload the nozzle (that is, exceed the working current of the nozzle), which will quickly damage the nozzle. The current intensity should be 95% of the nozzle’s working current. For example, the current intensity of the 100a nozzle should be set Is 95a.
- Keep the plasma gas dry and clean. The plasma cutting system needs clean and dry plasma gas to work normally. Dirty gas is usually a problem with the gas compression system, which will shorten the service life of consumable parts and cause abnormal damage. Test gas The quality method is to set the cutting torch in the test state and put a mirror under it to consume the gas in the cutting torch. If water vapor and mist appear in the mirror, you need to find out the reason and correct it.
- Cutting should start from the edge as much as possible and cut from the edge 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.
- Avoid the expanded and expanded 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 the cutting, which will cause abnormal damage to the nozzle. This problem can be avoided by using the correct edge start technique and the appropriate “arc breaking” signal time.
- Reduce unnecessary “arc (or arc guiding)” time. The consumption of the nozzle and electrode is very fast when the arc is started. Before starting, the cutting torch should be placed within the walking distance of cutting metal.
- Applying splash-proof chemical coatings on the protective shell Splash-proof chemical coatings can help reduce the accumulation of slag on the protective shell. But the protective shell must be removed from the torch before applying the splash-proof coating.
- Remove the slag on the protective shell.
What is the working principle of the CNC plasma table machine?
The method of using the thermal energy of the plasma arc to melt the material to be cut is called plasma arc cutting, which uses high-speed, high-temperature and high-energy plasma to quickly heat and melt the material to be cut, and with the help of internal or external high-speed gas (water) flow. The material is discharged until the plasma jet penetrates the back of the workpiece to form an incision, so as to achieve the purpose of cutting.
The temperature of the plasma arc column is extremely high, reaching 10,000°C to 30,000°C, far exceeding the melting point of all metallic or non-metallic materials. Therefore, the plasma arc cutting process does not rely on oxidation reaction, but on melting to cut materials. Its cutting application range is much larger than that of oxygen cutting, and it can cut almost all metals, non-metals, multilayers, and composite materials. And its cut is narrow (medium and thin plates), the quality of the cutting surface is good, the cutting speed is fast, and the cutting thickness can reach 160mm. Due to the high temperature and high speed of the plasma arc, it will not deform when cutting thin plates (≤0.5mm). Especially in the field of cutting stainless steel, titanium alloy, and non-ferrous metal materials, the choice of plasma cutting can not only achieve satisfaction The cutting quality can also obtain economic benefits that are ten times more than the original process. Therefore, plasma cutting has been more and more widely used in all walks of life.
How to choose the right CNC plasma table cutting machine?
For the selection steps of the CNC cutting machine, the user needs to comprehensively consider the cutting format size, structure form, cutting method, and height adjustment method.
- Width: Determine the effective length and effective width of the plate to be cut, and the approximate thickness range;
- Structure start: The structure of the equipment has four types: portable, gantry, desktop, and tube-sheet integrated machine.
The portable structure is simple, the equipment is easy to move and install, does not need to occupy a fixed factory building, and the equipment cost is low. However, due to the limitation of its structure, the transverse cutting width is limited, and the rigidity is poor during high-speed cutting. Gantry cutting machine, because it is a gantry type Supporting method, so the equipment has good rigidity and can realize a large span of 3-8m in the horizontal direction. The equipment installation requires high, which requires a special plant area, and is characterized by good long-term stability.
The desktop cutting machine is an integral structure, which is convenient to move in place, but the size of the cutting format is subject to certain restrictions.
The tube-sheet integrated machine can realize the two-in-one cutting function of the flat panel and the tube. One machine has multiple functions and is highly practical. Compared with the separate configuration of the flat panel machine and the intersecting line machine, the investment cost is low and the cost performance is excellent.
- Cutting method: The cutting method can be classified from different angles.
Flame cutting, plasma cutting, flame and plasma cutting machine;
Plasma is divided into dry plasma cutting and underwater plasma cutting;
CNC and straight cutting machine;
CNC intersecting line and flat plate integrated cutting machine.
(1) Flame and plasma cutting
Flame cutting: It is a traditional thermal cutting method, which is suitable for high-quality cutting of medium and thick carbon steel plates.
Plasma cutting: suitable for cutting carbon steel plates, stainless steel plates, and non-ferrous metals, and the cutting speed is faster than flame.
(2) Intersecting line cutting
In order to satisfy users for cutting round pipes, we have two different methods: one is a dedicated intersecting wire cutting machine; the other is a special part for intersecting wire cutting, which can be configured on the gantry CNC cutting machine. To complete the intersecting line cutting.
The former is suitable for high-volume professional intersecting wire cutting, and the latter is suitable for multi-purpose machines when the batch is not large, so as to reduce equipment investment and site occupation.
- Height adjustment method
Whether it is flame or plasma cutting, it is necessary to ensure that the height of the cutting nozzle from the steel plate is in the best state, so as to obtain a good cutting effect and a longer life of the cutting nozzle.
There are several ways to adjust the height:
- Raise the handle
The height adjustment of the handle is to adjust the height by driving the upper rack of the cutting torch through a gear;
- Electric button to increase
The electric button height adjustment is through the operation of the button, and the height adjustment motor drives the cutting torch to move up and down;
In the above two methods, the operator directly controls the lifting of the cutting torch.
- Capacitive automatic height adjustment
Capacitive automatic height adjustment is used for flame cutting.
Flame cutting is equipped with capacitive automatic height adjustment. On the one hand, it can automatically adjust the cutting torch according to the height of the steel plate to ensure that the height of the cutting nozzle from the steel plate remains constant; on the other hand, when the preheating is completed, when the When iron slag backsplash occurs, it is easy to block the cutting nozzle at this time. When the automatic height adjustment is configured, the cutting torch will be automatically lifted before the cutting oxygen is turned on. After the iron slag splash is completed, the cutting torch can be moved down. Reduce the occurrence of clogging of the cutting nozzle. However, due to the high temperature during the flame cutting process, the induction ring will be melted and the service life will not belong, so there is no need for special needs and no recommendation;
- Arc pressure automatic height adjustment
Arc pressure automatic height adjustment for plasma cutting.
Plasma cutting, on the one hand, the cutting speed is fast, on the other hand, the arc is very dazzling. Therefore, depending on the operator to observe the height of the cutting nozzle from the steel plate at any time and adjust it in time, not only the reaction speed cannot keep up, on the other hand, the eyes cannot bear it. This is especially true when the sheet is thinner. Therefore, under normal circumstances, it should be equipped with automatic arc voltage adjustment. The automatic arc voltage adjustment of our company’s equipment is a standard configuration. Regardless of whether the user indicates, it will be equipped with a plasma arc voltage automatic And plasma anti-collision device.
How to maintain the desktop plasma cutting machine?
- Clean the torch body
Disassemble the torch parts and inspect the inside of the torch. Check the threads for signs of mechanical damage. Use electrical contact cleaner and cotton swabs to clean the inside of the torch. Disconnect the torch from the torch fixed tube and slide the fixed tube back, Expose the torch cable connector. Check any connector for leaks or damage. Blow out all-metal dust that has accumulated.
- Clean the torch cable
Thoroughly clean or blow the entire torch cable to remove the accumulated metal dust and dust. Metal dust may deplete the high voltage required to start the plasma arc. Check for kinked or frayed hoses, bare wires, and cracks Check if the high-frequency shielding layer is properly grounded.
- Clean the power supply
Use a clean and dry workshop air source to blow away all accumulated metal dust. Metal dust may cause damage to power components (especially PCB). Contactors, relays, and spark gap components may also malfunction due to excessive accumulation of metal dust. Check the air filter on the power supply housing; replace if necessary.
- Check the torch cooling components
For water-cooled cutting torches, check the coolant flow in the cooling tank for signs of air intake or flow reduction. Make sure that the gallons per minute of the coolant return meets the regulations. Check whether the flow switch on the return pipe is working properly-coolant Insufficient flow can cause the torch to overheat. Check and clean the coolant filter and water pump filter, and replace it if necessary. Use a conductivity meter (if available) to check the coolant resistivity. For most systems, the resistivity must not exceed 10 Micro-Ohm. Pour out and refill the coolant every 6 months.
- Check the water quality
The quality of the secondary water supply is particularly important for the water jet cutting torch. The hardness of the water must not exceed 8.5 ppm or 0.5 grains. Hard water will cause mineral deposits to accumulate on the nozzle, which will shorten the nozzle life. If necessary, use a commercial water softener. The water quality in the water bed is also very important. If the water in the cutting bed is heavily contaminated by slag and metal dust, it will be difficult to start the plasma torch. Moreover, it may also cause rust on the cutting parts.
- Check the plasma gas
Gas quality is essential to maintain a long component life and good cutting quality. To check the air quality, the system can be placed in test mode, and a clean paper towel is placed under the torch as the air flows through the system. Check for moisture, oil mist, or particle contamination. Check the filter once a week; once the dehumidifier starts to accumulate water, dump it immediately.
7.Clean machine components: rails, gears, brackets, etc.
Use degreasers and abrasive pads to remove grease, dust, and metal dust. Use dry lubricants (such as graphite powder) to lubricate the gears. If the bearings have lubricating joints, lubricate them. Do not lubricate the guideway part-the lubricant will adsorb Contaminants, leading to excessive wear.
- Level and align the rails
Use a piece of tool steel or other precision rulers to check the joints of the guide rails to see if they are not aligned. The guide rail alignment can avoid excessive resistance to the drive motor. The guide rail spacing of the entire system should be consistent.
- Align and adjust gears and bearings
The gear must not overlap with the rail above or below. Adjust the gear centering to eliminate the gap between the gear and the bracket. Align the rail with the cross drive. After the bearings are aligned, the gap between the bearing and the rail or cross drive should be kept to a minimum These bearings are usually installed on an eccentric wheel. Adjust until there is no light visible between the bearing and the surface of the guide rail. Do not overtighten. With the transmission gear loosened, roll the beam on the guide rail to check whether it is not Smooth. Adjust accordingly until the beam can roll freely with minimal vibration and almost no resistance.
- Check the verticality of the cutting torch relative to the cutting bed and the workpiece
The collision may hit the torch, making it not at right angles to the workpiece.
- Check the torch fixed equipment
This causes vibrations, which creates wavy cuts.
- Check the safety limits that need to be correctly observed to ensure operational safety and prevent machine damage.
Move the machine to each limit to test the switches. Make sure that the machine stops when each switch reaches the limit. Check the mechanical limit devices to make sure they are working well.
- Adjust the drive motor and controller
If the drive motor seems to be out of sync (the torch may not be able to return to the zero position, or the inaccuracy of the cut piece may increase, especially if the x-axis and y-axis drives are moving in combination), it may be necessary to adjust the motor. To position the cutting torch correctly, the speed of each axis must be equal. In addition, motor drift must be minimized.
Precautions for the operation of desktop plasma cutting machines.
- Assemble the torch correctly
Install the cutting torch correctly and carefully to ensure that all parts are well-matched to ensure gas and cooling airflow. Installation put all the parts on a clean flannel to prevent dirt from sticking to the parts. Add proper lubrication to the o-ring Oil, subject to the brightening of the o-ring, do not add more.
- Consumable parts should be replaced in time before they are completely damaged
Do not replace the consumable parts after they are completely damaged, because severely worn electrodes, nozzles, and swirl rings will produce uncontrollable plasma arcs, which can easily cause serious damage to the cutting torch. So when the cutting quality is found to be degraded for the first time, Consumable parts should be checked in time.
- Clean the connecting thread of the torch
When replacing consumable parts or daily maintenance and inspection, be sure to ensure that the internal and external threads of the torch are clean. If necessary, clean or repair the connecting threads.
- Clean the contact surface of the electrode and the nozzle
In many cutting torches, the contact surface between the nozzle and the electrode is a charged contact surface. If these contact surfaces are dirty, the cutting torch will not work properly and should be cleaned with hydrogen peroxide cleaning agents.
- Check gas and cooling gas every day
Check the flow and pressure of the gas and cooling airflow every day. If you find that the flow is insufficient or leaks, you should stop the machine immediately to troubleshoot.
- Avoid torch collision damage
In order to avoid collision damage to the cutting torch, it should be programmed correctly to avoid the system from overrunning. The installation of an anti-collision device can effectively avoid damage to the cutting torch during a collision.
- The most common causes of torch damage
(1) Cutting torch collision.
(2) Destructive plasma arc caused by damage to consumables.
(3) Destructive plasma arc caused by dirt.
(4) Destructive plasma arc caused by loose parts.
- Matters needing attention
(1) Do not apply grease on the cutting torch.
(2) Don’t overuse O-ring lubricant.
(3) Do not spray anti-splash chemicals while the protective cover is still on the torch.
(4) Do not use the manual cutting torch as a hammer.