One, the welding wire has a hard bend
Cause: The welding wire does not bend hard during production, but it is bumped during the handling process and the welding wire of the welding wire spool is scattered, or this phenomenon occurs when the scattered welding wire is manually wrapped around the welding wire spool.
Caused phenomenon: After the welding wire with a hard bend enters the wire feeder, it will be blocked before entering the welding gun. Once it enters the welding gun, it will also be blocked by the wire feeding hose or the contact nozzle, so that the welding cannot be performed, and the welding current , When the voltage is too large, the contact tip will be burned.
Note: When unpacking and installing welding wire, carefully check the wire reel to make sure that the wire reel is intact and the wire is wound neatly before use. When handling the welding wire, it must be handled with care to avoid scratching the welding wire reel and causing the welding wire to scatter. When rewinding the scattered welding wire to the welding wire reel, it should be carefully wrapped with gloves to avoid hard bends.
Two: The wire is corroded
Causes: The packaging of the welding wire is damaged during transportation, the welding wire warehouse is too damp, the humidity exceeds the standard, the storage time is too long, and the welding wire is stored after being touched by hand.
Caused phenomenon: During welding, when the rusted welding wire enters the wire feeder, the pinch roller will slip, affecting the normal wire feeding. When the welding wire with rusted parts enters the welding gun, due to the increase in the diameter of the welding wire, it will be blocked by the contact tip and cannot be welded.
Matters needing attention: When unpacking the welding wire, check whether the welding wire is rusted, and the rusted welding wire should be replaced in the welding wire warehouse in time. The welding wire packaging should not be damaged, and the humidity of the welding wire warehouse should be controlled. The welding wire should be stored 300mm away from the ground and the wall. The purchased welding wire should be used first, and the opened welding wire should be carefully touched by hand.
Three, the wire thickness is uneven or has burrs
Cause: It is caused by the unqualified wire drawing equipment during the production of welding wire.
Caused phenomenon: During welding, when the welding wire with uneven thickness or burrs enters the wire feeding hose of the welding gun, it will rub against the wall of the hose and vibrate. When the vibration gradually approaches the welding gun and enters the contact tip, the wire feeding will be unstable. , intermittent welding or stuck phenomenon.
Matters needing attention: After replacing the new contact tip, there is still intermittent welding. Use the contact tip of the matching type to check the welding wire before welding. It must be that the diameter of the welding wire is not uniform and the welding wire should be replaced.
Four, improper use of wire feed pinch rollers
Cause: The wire feeder pinch wheel should be matched with the welding wire, the solid carbon steel welding wire uses a steel wheel, and the flux cored welding wire uses a ceramic wheel, and the wheel groove type matches the diameter of the welding wire. The pressure is adjusted according to the requirements of use, and it should not be too loose or too tight.
Caused phenomenon: When the carbon steel solid core welding wire uses the ceramic wheel, it will cause the ceramic wheel to wear too fast. When a steel wire feeder is used for the flux-cored welding wire, the flux-cored welding wire will be crushed and cracked, so that the flux will leak out and cannot be welded.
When the diameter of the carbon steel solid welding wire is larger than the groove diameter of the wire feeder, it is easy to produce indentation on the welding wire, which will deform the circular section of the welding wire, and the welding wire part with the indentation will be stuck when it passes through the contact tip.
When the diameter of the welding wire is smaller than the groove diameter of the wire feed wheel, the friction between the wire feed wheel and the welding wire is insufficient and slips, and the wire cannot be fed normally.
When the wire feed roller matches the diameter of the welding wire, the pressure of the wire feeder pinch roller should also be appropriate. If the wire feed roller pressure is too large, the welding wire will be deformed. If the wire feed roller pressure is too small, the friction between the wire feed roller and the welding wire will be too small. , when the welding wire is resisted in the wire feeding hose or on the contact tip, the wire feeding instability will occur.
Matters needing attention: Use steel or ceramic wire feed rollers as required. The groove type of the wire feed roller should match the diameter of the welding wire. The pressure of the wire feed roller should be moderate, and the grooves of the wire feed roller should be cleaned frequently.
Five, when the welding gun is used, the bending is too large and too fast
Cause: Too random during welding or the spatial position of the special welding seam makes the bending of the welding torch too large.
Caused phenomenon: It will cause the welding wire to be blocked too much when running in the wire feeding hose of the welding gun, resulting in difficulty in wire output and unstable wire feeding.
Precautions: When welding, the welding torch should be kept at a straight or large bending angle to reduce the running resistance of the welding wire in the wire feeding hose.
Six, grooves are ground in the gun wire spring hose
Cause: The wire feeding spring hose of the welding gun has been used for too long, and when the welding wire passes through the wire feeding hose, the groove is ground inside the hose.
Caused phenomenon: During welding, when the welding wire enters the groove ground in the wire feeding spring hose, when the welding torch moves and the bending degree changes, the groove wire will be clamped, which will hinder the normal operation of the wire feeding.
Note: When the wire feeding spring hose is used for a long time, the wire is not smooth, the wire feeding hose behind the welding torch handle trembles or the wire is blocked with the change of the welding torch angle, the wire feeding spring hose should be replaced in time . Try to maintain a large bending angle of the welding gun to reduce the friction of the welding wire in the wire feeding hose.
The wire spring hose is too short in the welding gun, which will cause the welding wire to bend inside the welding gun, resulting in poor wire feeding. When the wire feeding spring hose is too long inside the welding gun, it will bend, which will increase the frictional resistance of the wire feeding and cause the wire feeding to be unstable.
Seven. The contact tip was not cleaned in time
Cause: When the welding specification is not adjusted properly, or when the welding torch is too close to the molten pool, the longer the welding time is, the more welding spatter sticks to the contact tip.
Caused phenomenon: The more the contact tip of the welding torch splashes, the easier it is to block the wire outlet hole of the contact tip, thereby increasing the resistance of the wire feeding, causing the welding wire to be blocked or blocked.
Matters needing attention: Adjust the angle of the welding torch and the stretching length of the welding wire as required to reduce the generation of spatter, so that the spatter on the contact tip is often cleaned with needle-nose pliers, and the welding wire is extended out of the contact tip after cleaning for 10~ 15cm long, use needle-nose pliers to bend the welding wire from the base of the contact tip, then rotate it clockwise or counterclockwise for 3 to 5 turns, and then release it quickly. Use the force of the welding wire to turn the wire feeding hole of the contact tip into a smooth shape.
Eight, the contact tip wire feed hole is too worn
Cause: The wire feeding hole is too large after a long time of wire wear of the contact tip during welding.
Caused phenomenon: The wire feeding hole of the contact tip is too large, which will cause poor conductivity during welding, and the discharge of the welding wire and the contact tip will make the wire feeding unstable or stick to the contact tip, accompanied by the phenomenon that the welding wire swings back and forth in the molten pool, which affects the welding seam formation. .
Matters needing attention: When it is found that the welding wire swings back and forth after coming out of the contact tip, and it is accompanied by the phenomenon of sticking with the contact tip, it should be replaced with a new contact tip in time.
The contact tip of the welding gun should match the diameter of the welding wire. If the diameter of the contact tip hole is too small, the frictional resistance will be too large, the welding wire will not be smooth or the wire will be blocked.
Nine, the voltage and current do not match during welding
Cause: Insufficient experience when welding is not adjusted according to the specified welding specifications.
Caused phenomenon: when the current is too large and the voltage is too small, intermittent and unstable welding will occur, the welding spatter is too large, and the excessive noise of the welding wire to the molten pool will be loud and chaotic. When the current is too small and the voltage is too large, the welding fume will be too large, the sound of the welding wire to the molten pool will be small, and the welding wire and the contact tip will melt and stick together at the same time and cannot be welded.
Matters needing attention: According to the production needs, adjust according to the welding specifications, so that the welding wire will melt in time when it enters the molten pool, and the sound of the welding wire going to the molten pool will be uniform.
In addition to the above nine reasons, there may also be poor quality of the welding machine, unstable operation of the wire feeding motor, poor bonding of the copper plating layer of the welding wire, loss of copper powder, and clogging of the contact tip, which will cause unstable wire feeding.
If the fixed shaft of the wire reel of the wire feeder is too loose, the welding wire will be loosened, and if it is too tight, the wire feeding resistance will be too large and the wire feeding will be unstable.
During welding, the loose ground wire or the rust at the contact point is not cleaned, resulting in excessive resistance and unstable arc, which will affect the wire feeding. The contact tip is not tightened, resulting in unstable welding current and voltage and unstable wire feeding.
A good welder can also judge the cause of uneven wire feeding according to the vibration generated by the welding wire running in the welding torch when welding.
During welding, when the jiggling occurs behind the handle of the welding gun, most of the wire feeding hoses are ground out of the groove; when the vibration moves forward with the wire feeding, this phenomenon is mainly caused by bending or pressing on the welding wire. Marks and burrs; when chatter occurs in front of the torch handle, the contact tip should be replaced in time.
The above experience can provide judgment basis and solutions for unstable wire feeding during CO2 gas shielded welding operation, thereby improving production and product quality.
