Views: 232 Author: DURMAPRESS Publish Time: 2021-06-07 Origin: DURMAPRESS
CNC Plasma cutting machine is a high temperature, high speed plasma arc as heat energy, melting the metal is cut, and with high speed airflow will melt the metal blown away.It can cut all kinds of metal materials (stainless steel, carbon steel, alloy copper, aluminum, copper, nickel, titanium, etc.), with the characteristics of fast cutting speed, narrow incision, small deformation, saving materials and so on.
Air CNC Plasma cutting machine is compressed air as the air source, because of frequent work, work place often move and poor environmental conditions and other reasons, prone to failure.Here, LGK8-63 Plasma Cutter Machine is taken as an example to analyze its basic working principle and introduce some common fault maintenance treatment. The principle diagram is shown in the attached diagram.
The points from the structure and working principle of air plasma cutting machine mainly includes: main circuit, control circuit and the gas circuit three parts. 1, the main circuit including B1 contactor KM, three-phase transformer, three-phase bridge rectifier (consist of D1 ~ D6, C1 ~ C6), high frequency oscillator (consist of B2, B4, FP, C12). 2, control circuit by the control transformerB3 and J1, J2, J3, D7, C11, R3 and other components.
The principle is briefly described as follows: after connecting the power supply and air supply, close the switch K1. The power indicator XD is on, and the cooling fan FM turns immediately.Press the cutting torch micro-switch K3, relay J1 is operated by electric operation, its normally open contact is connected, solenoid valve DF is operated, air circuit is connected, and the cutting torch is ventilated in advance.
The other normally open contact is connected to the resistor R3, and the diode D7 charges the capacitor C11 to form a delay circuit. After 3~5 seconds, the charge is completed.Relay J2 is energized and closed, contactor KM is energized and the main loop is energized and passes through the rectifier bridge of transformer B1.The positive electrode is directly connected to the workpiece through the connecting line B5, and the negative electrode is output through B2. When the main circuit is powered, the auxiliary normally open contact of contactor KM is connected to the relay J3.DK is normally closed contact, so that the converter B4 is powered.The primary voltage of B4 is 220V, which is taken from the primary autocoupling tap of transformer B3, and the secondary voltage of B4 is about 2500V, which is output to the transformer B2(primary winding 3 turns) of the high voltage capacitor C12(102M/10kV two parallel).The secondary winding is 10 turns in series to the working main circuit). Through the transformer B2, the negative pole of the main circuit is inductively superimposed - high voltage, the cutting torch is close to the contact workpiece (positive pole), and the arc is initiated for cutting.
FP in the figure is the protective discharge air gap, the spacing can be adjusted, the normal is 1~12mm. When the arc cutting workpiece.The arc current disconnects the contact point of the dry reed tube DK in the coil B5(8 turns), the relay J3 loses power, the high voltage transformer B4 is cut off, and the arc boosting loop stops working.When the cutting is finished, release the cutting torch micro-switch K3, then relay J1 power off reset, contactor KM main contact is disconnected, the main loop stops output.
Due to the charging and discharging function of C11 in the RC circuit, relay J2 is delayed and reset, so that the gas path is disconnected after a lag of 10 seconds, and the cutting torch is effectively cooled and protected.The whole cutting process: pre-ventilation, a main circuit power supply - high voltage arc ignition - arc extinguishing - gas hysteresis - stop.Transformer B1 is Y/Y connection method, the primary side line voltage is 380V, the secondary side line voltage is 170V, after rectification, the DC no-load voltage is 240V effective value, when there is a workload output 120V.
Two, the defect of plasma cutting machine
This type of plasma cutting machine, from its schematic diagram or the actual structure to analyze the main loop, control loop, etc., does not use integrated circuit, although the structure is simple, but there are some defects.Because the power supply is connected to a terminal board on the machine, and then directly connected to the contactor KM from the terminal board.On/off is just to turn on/off the control loop switch K1 and then control the contactor Km. In practice, if the contactor Km core gets stuck or contacts sinter (this fault is very common), the cutting machine still has voltage output.Failure to switch off the power supply is likely.From the perspective of protecting equipment and staff or maintenance, at least a three-phase circuit breaker with a capacity of about 30A (estimated according to equipment capacity) is required between the power supply line and the contactor KM.
It is worth mentioning that in the process of arc starting, the uncut workpiece is the main circuit, the control circuit works,J3, B4 work, there is an arc starting voltage on the number of B2, superimposed on the main circuit.
As can be seen from the figure, the voltage of the arcing component;Through the output of the workpiece, the inter-wire capacitance C13 of the lead wire, and the line-ground capacitance C14 and C15 are coupled, which are inversely added to the secondary of the transformer B1 and fed back to the power supply side through the inter-turn capacitance C16 of the winding, causing pollution to the power supply.With a high internal resistance digital multimeter DC voltage 1000V gear, a meter and pen overlap the power supply into any phase, the other pen is suspended, the digital multimeter display value is an unstable value (much higher than 0V).
Automatic plasma cutting pipe equipment, automatic plasma cutting pipe machine industry product development has broken the traditional boundary between welding and cutting, its products have been bridged welding, cutting two industries, there are many enterprises produce welding and cutting equipment at the same time.Cutting machine industry also exists in the market disorderly competition, performance in each other depreciate, pressure each other, dig each other;Little or no investment in R&D;In the mechanical and control level with foreign products, there is little difference, only stay in the level of application;There is no cooperation between enterprises and they cannot join hands to open up the market. In the procurement of accessories, centralized enterprises will reduce costs and other problems.
Automatic plasma cutting pipe equipment cutting accuracy: for the construction industry class general requirements below ±0.5mm on the line;But for the automotive mirror class requirements in ±0.01mm below.Now the mechanical manufacturers can provide the cutting accuracy is generally below ±0.2mm, but this can not only look at the introduction of the product manual, in the acceptance should have a complete set of testing cutting precision procedures, to measure the actual cutting product accuracy shall prevail, we generally have more than a dozen test sample surface.Through testing, we can master the flatness of the cutting platform and the synchronous control level of the control system.
Automatic plasma cutting pipe machine cutting speed: we can talk about the speed under the premise of meeting the cutting accuracy. Because the cutting platform is short, it is difficult to judge whether the speed is reached with the eyes. We can use the software simulation function of the servo drive of the cutting machine to check whether the speed of the motor is reached.When testing the cutting speed, no real cutting is used to improve the adding and subtracting speed.Each axis can be tested separately or simultaneously.Automatic plasma cutting factory automatic layout optimization function: on the side of the cutting machine, considering the particularity of processing costs and break off the piece of work, generally not highly educated people to dry, which requires cutting machine operation is simple, and easy to understand, not too complicated, otherwise there will be a great affordable machines couldn't afford the embarrassing situation.
Choose plasma cutting machine according to requirements
How to choose the right cutting method according to the requirements of the plasma cutting machine in the field of modern industrial manufacturing, cutting is a large amount of application, the application of a wide range of basic technology, cutting methods are punching, shear, flame cutting, EDM, water cutting, plasma cutting, laser cutting several.Various cutting methods have their own advantages, and there are some limitations.The efficiency and quality of cutting will directly affect the efficiency and quality of production. How to choose the appropriate automatic plasma cutting pipe machine should pay attention to the following factors:
1, automatic plasma cutting pipe machine cutting material type, thickness, size
2, the size of the automatic plasma cutting pipe machine cutting, cutting speed requirements
3, automatic plasma cutting pipe machine cutting precision requirements, requirements for material deformation, the size of the secondary processing quantity
4. Can the automatic plasma cutting pipe machine adopt the optimized nesting software to improve the material utilization rate
5, automatic plasma cutting pipe machine to be processed material selection, material, hardness, such as low carbon steel, stainless steel, aluminum, copper, non-metal is processed workpiece shape, plate cutting or need to carry out three-dimensional processing of the workpiece
6, automatic plasma cutting pipe machine one-time investment, maintenance costs, whether the need for mold and other additional investment, equipment investment and economic benefits of comprehensive comparison CNC shred machine: commonly used to cut the straight edge of the plate blank, the accuracy is poor.CNC punch: punch in stamping forming parts, need a variety of punching dies, each shape or each size need a pair of punching dies, which greatly constrains the machine tool modification and update speed, general CNC punch workpiece thickness is less than 10mmHigh processing precision, suitable for small batch, many varieties of parts processing, reduce the cost of mold production, shorten the production cycle.
Rapid inspection of plasma cutting machine
Automatic plasma cutting machine, automatic plasma cutting equipment, plasma cutting machine quick inspection, plasma cutting in use after some time began to have customers reflect that the cutting speed decreased, cutting accuracy is also declining, the noise is bigger, the reason is that there is no regular inspection of plasma cutting,The following sea Chen mechanical and electrical sharing should be from what aspects to do the inspection of plasma cutting, find problems, prevention.
1. Longitudinal movement of automatic plasma pipe cutting machine: check the roller, pay attention to iron oxide particles, etc., clean the roller when necessary, and slightly smear with oil.Check the straightness of the guide rail, check and clean the guide rail, pay attention to whether there are iron oxide particles, etc., clean the guide rail when necessary, and apply a layer of oil film.Check rack, contents as above.
2, automatic plasma pipe cutting machine transverse movement: check the guide rail, rack, steel belt on the beam, clean if necessary, dry after coating a layer of oil film.Check the action of the lateral motion limit switch.Check the tensioning force of the steel strip (about once every six months) and adjust if necessary.
3, automatic plasma pipe cutting equipment frame: check all the frame, adjust if necessary, which should also check the clamping device.
4. Automatic plasma tube cutting equipment inspection and automatic adjustment: check the performance of automatic adjustment and make correction if necessary. If damage is found, the detection ring and probe head should be replaced.
4. Gas path system of automatic plasma pipe cutting equipment: check the performance of the gas path system, check whether the valves and pipe joints are leaking, and tighten them if necessary.
5. Electric inspection of automatic plasma tube cutting equipment: please refer to the electrical manual of CNC cutting machine.
7, automatic plasma cutting machine factory performance test: check the performance of all buttons and selector switches, diagonal precision test.
I. Equipment structure features:
1) Main girder features: transverse and longitudinal guideways are made of the overall high strength aluminum alloy die opening, good stability, light, no deformation, beautiful and elegant, easy to move and cut on site, improve efficiency, easy to install and packaging.
2) The characteristics of the bottom plate: 10mm aluminum alloy plate, the holes processed on the bottom plate are processed by CNC machining center, the accuracy is guaranteed, the service life is longer.
3) Oxygen and acetylene pipes have been provided on the cross beam, which is convenient and safe without connecting the air pipe.Longitudinal guide rail has a fixed slot, easy to fix the guide rail.
Two, chassis side panel features:
1) The new combined chassis structure design, the cross arm and the main console as well as the mechanical and numerical control parts can be decomposed and combined.
2) The plug plate and the cabinet are split, which is easy for maintenance and loading. Fan cooling is added to avoid the high temperature inside the cabinet.
3) The plug board is equipped with a 4-core plasma interface (arc starting and arc pressure detection). If plasma is not selected, the equipment is also equipped with a plasma interface for backup.
4) Equipped with off-line switch, easy to cut the gun to find the benchmark, improve efficiency, there is an emergency stop switch, emergency use.
5) The background color of the equipment shall be red.
Three, the internal wiring bureau:
1) All standard wiring grooves in the internal wiring of the bottom plate are routed, and the signal corresponding to each wire head is marked by the signal tube for easy maintenance.
2) The transmission part adopts spring tension to ensure precision and no clearance, gear and rack transmission to ensure accuracy and eliminate clearance.
3) The motor adopts stepper motor drive technology, and adopts high subdivision driver, with high precision and stable operation
IV. Core features of our equipment:
1. Thoughtful and fast pre-sale, in-sale and after-sale service, quick response and quick solution in case of failure;
2, fast delivery cycle, standard parts can be supplied from stock;
3, the equipment adopts baking paint process, paint adhesion is stronger, more beautiful and durable;
4, The upper part of the cutting gun can adjust the direction, the operation is more convenient;
5. Consumerable materials need not be customized, economical and affordable;