Knowledge key points of welding and cutting equipment maintenance
The welding and cutting equipment in the use process, especially the novice, may encounter a lot of problems. This article explains some common knowledge of welding equipment maintenance, which can help you to solve common problems.
1. The instability of field grid voltage during welding results in the failure of some welders to work normally.
An electrolytic capacitor (CD11-400V-1000, -M, 2) is added to the DC side of the three-phase bridge inside the welding machine.
2, over current protection failure of welding machine
(1) the welding machine is short of phase: the welding machine can not start normally. This kind of fault is easy to find. Malfunction can be found by measuring the power supply with Multimeter or electric pen.
(2) one phase contact of the power supply is virtual: this kind of fault is hard to find, because the power supply voltage displayed by the multimeter is normal. Most of the welders start normal at no load, but when the test is welded, the phase of contact appears as a result of the sudden increase of load. Or the welding machine test machine, work all normal, after a long time work, due to the power supply circuit heat, resulting in power supply capacity decline, welding machine over current or undervoltage protection, and then measure the power voltage, and restore normal.
3. Press the welding switch to keep the wire feeder.
Specific phenomenon: NB-500 (A160-500) gas protection welder, boot display normal, use the 2 step welding mode or empty the gun switch, loosened the back wire does not stop.
Solutions: in the process of using equipment, the reliable connection of fast plugs and sockets is not paid attention to. Long time virtual connection causes overheating oxidation, so that the feedback line connected to the inside of the welding machine outlet is in bad contact with the fast socket bolt, and the resistance is measured and the fault is eliminated after reconnection.
4. The cutting torch of ion cutting machine is easy to damage and can not lead to arc
(1) keep the dry and clean of plasma gas
Plasma system needs dry and clean plasma gas to work normally. Dirty gas is usually a problem of gas compression system. Oil and water often enter the gun body, which will shorten the service life of vulnerable parts and cause abnormal damage.
(2) to ensure the proper pressure and flow
The pressure and flow of plasma affect the service life of vulnerable parts very much. 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. Recommended LGK-60 and LGK-120 plasma cutting machine cutting torch (gun) outlet pressure 5bar.
(3) adopting reasonable initial cutting height
A reasonable starting cutting height (the distance between the nozzle and the workpiece surface) is recommended for 3 ~ 10mm. The perforation requires the beginning of the cutting height to be above 5mm.
5, the plasma cutting machine is irregular and burr (slag).
(1) the flow pattern of molten metal is not good. When the power of the power is too small or the plasma arc is not compressed well, the melting metal temperature is low and the fluidity is poor during the cutting process. At this time, even if the air blowing force is strong, it is not easy to blow all molten metal away, thus forming burr.
(2) when cutting thick plate, due to the excessive backing of the slotting. During cutting, the heat of each part of the metal is different. When the flame of the plasma arc is shorter and the cutting speed is too fast, the rear support increases. The vertical component of the arc blowing force causes the molten metal to be blown away, and the horizontal component flows the molten metal back along the bottom of the incisive. This part of superheated metal melts the bottom of the incision, and then melts together to form a burr.
(3) the burr is formed due to the overheating of the bottom. When the cutting speed is too low, the lower end of the incision is overheated and even melts, the combination of the liquid metal and the bottom metal increases, so the molten metal is more difficult to be blown off by the air and go to the burr.
(4) the gas blowing force is insufficient. When cutting, if the blow force is not large enough, it will not be enough to ensure that the molten metal is blown away and burrs are formed.
6, welding power starts normal, but only small spark can not weld normally when welding arc.
(1) check whether the three-phase electricity is normal.
(2) check whether the feedback line is connected to normal.
(3) check whether the output terminals and the welding circuit are normal.
(4) check whether the thrust potentiometer is invalid.
(5) check whether the current sensor is invalid.