Failures of carbon dioxide gas shielded welding equipment are mainly caused by wear and tear of the mechanical parts of the equipment and improper adjustments during use. The main parts of the failure mostly occur in the connection between the wire spool, the V-shaped groove pressing wheel of the wire feed wheel, the wire feed nozzle, the spring hose, the conductive nozzle, the welding gun hose, the nozzle and the ground wire.
The main faults of the welding wire spool are that the welding wire is easy to loosen, the wire feeding motor is overloaded, the wire feeding is uneven, and the arc is unstable. The welding wire is easily stuck on the contact tip, as shown in Figure-Wire spool failure. The reason why the welding wire loosens easily is that the wire spool brake is too loose; the reason why the wire feed motor is overloaded is that the wire spool brake shaft is too tight and the welding wire cannot be output normally.
The failure of the V-shaped groove of the wire feed wheel is mainly due to uneven wire feed speed and deformation of the welding wire during transportation. Sometimes there may also be difficulty in wire feeding, as shown in Figure-V-groove failure of wire feed roller. The reason for this failure is that the V-shaped groove of the wire feed wheel has been worn or the V-shaped groove itself is too large. In addition, if the V-shaped groove is too small, the welding wire will be deformed due to extrusion and even the welding wire cannot be output normally, resulting in difficulty in wire feeding. .
Failures of the compression wheel are mainly manifested in deformation when feeding the welding wire, difficulty in wire feeding, rapid wear of the wire nozzle, and sometimes uneven wire feeding, as shown in Figure- Pressure wheel failure. The main reason for this failure is that the pressure of the pressing wheel is too high or too low. When the pressure is too high, the welding wire output space becomes smaller, and the welding wire is deformed under pressure. The deformed welding wire cannot be output normally, causing the wire nozzle to wear faster; when the pressure is small, the power to output the welding wire is not enough, and the welding wire is fed quickly. Slow and uneven wire feeding speed.
The main faults of the wire feeding nozzle are that the welding wire is easy to bend, the welding wire is not fed smoothly, the friction resistance of the welding wire is large, and the wire feeding is blocked, as shown in Figure-Faulty thread feeding nozzle. The main reason for this failure is that the orifice of the wire feed nozzle is too large, or the distance between the wire feed nozzle and the wire feed wheel is too large, leaving room for movement of the welding wire during transportation. However, if the wire feeding nozzle is too small, the frictional resistance between the welding wire and the nozzle hole will increase, causing resistance to the feeding of the welding wire.
The main faults of spring hoses are that the welding wire is easy to bend and the wire feeding is sometimes blocked. This is caused by the inner diameter of the hose being too large. When the inner diameter is too large, the swimming gap of the welding wire increases, so the welding wire is easy to bend. High friction resistance and blocked wire feeding are also faults. The reason is that the inner diameter of the hose is too small or is blocked by dirt, so it must be cleaned in time. The reason for poor wire feeding is that the hose is too short and the welding wire cannot stretch and run freely; the welding wire that is too long will also increase the frictional resistance of the welding wire, making wire feeding difficult or even blocked, as shown in Figure-Spring hose failure
When long-term welding causes the contact tip to wear or its aperture to increase, the contact point between the welding wire and the contact tip will often change, making the arc unstable and causing the weld to be uneven during welding; if the aperture of the contact tip is too small, This will increase the friction between the welding wire and the hole wall, making the welding wire unsmooth during the feeding process. In severe cases, it will cause copper inclusion in the weld, as shown in Figure-Contact tip failure.
If the bending radius of the welding gun hose is too small, the frictional resistance of the welding wire advancing in the hose will increase, and the normal feeding of the welding wire will be hindered, sometimes resulting in uneven speed or the inability to feed the welding wire at all, as shown in Figure-Welding gun hose failure Show.
If the spatter is too large during the welding process, causing the spatter to block the nozzle, the protective effect of the gas will be poor, it will easily cause pores in the weld, and the arc during welding will be unstable and uneven; if the nozzle is loose, Air will be inhaled during welding, and the protective effect of the gas will also become worse, resulting in pores during welding, as shown in Figure-Nozzle failure.
If the ground wire is loose during welding or there is obvious rust at the contact point with the weldment, the contact resistance increases and arc ignition cannot be carried out, or the arc combustion becomes unstable even after forced arc ignition, as shown in Figure-Ground connection failure. At this time, the welding machine (workpiece) should be fully grounded.
The faults of Carbon dioxide gas shielded welding equipment should be accumulated and summarized through continuous practical welding experience. As long as through long-term practical training, one can skillfully grasp the causes of equipment faults and eliminate them in time.