What are the causes and solutions of the serious wear of the mig contact tips？
At present, the mig contact tips is frequently replaced. The appearance is: the outlet of the mig contact tips is worn, leading to wire feed deflection, and the actual welding trajectory is offset, that is, the position of the TCP point is offset, resulting in welding defects such as welding deviation or welding leakage.
1. mig contact tips failure reason
The wear of the mig contact tips itself comes from the wear at the outlet of the mig contact tips due to the friction of continuous wire feeding at the increasing temperature of the mig contact tips, which often leads to calibration errors and affects the production efficiency during robot welding.
Should try to reduce the temperature of the mig contact tips, including in the mig contact tips composition, mig contact tips structure processing, mig contact tips material:
Brass, copper, chromium zirconium copper and other materials, brass is the most inferior, copper is slightly better, chromium zirconium copper is the best; Ceramic components are even added to the mig contact tips to increase wear resistance.
mig contact tips processing accuracy, due to the accuracy of processing equipment or other problems, the inner hole of the mig contact tips finish and concentricity is not good enough.
2.Wire straightening and surface finish
The wire is often tube or plate, with burrs or ribs, so it may affect the contact between the wire and the mig contact tips, and in welding, the mig contact tips should be stable under the premise of the minimum friction.
The mig contact tips life of dirty welding wire may be only one third of that of clean welding wire.
To determine the quality of welding wire, annealing stress elimination degree of welding wire, performance is how straightening, the test is:
50mm in the front of the welding gun nozzle, whether the wire can automatically bend, bending forward indicates that the wire is too soft, bending back indicates that it is too hard, hard wire on the conductive mouth the most cost;
Secondly, whether the wire feeding hose is bent from the wire feeder to the welding gun will also cause the bend of the welding wire.
3.Arc instability leads to arc backburn
The causes include poor arc, arc instability, wire feeding, workpiece surface cleaning degree, but does not necessarily affect the performance of the mig contact tips itself, at this time the welding fault is roughly related to the characteristics of welding power supply, wire quality, wire feeding effect, wire feeding hose and mig contact tips structure design.
When the conductive point in the welding wire and the mig contact tips is often changed, its life is only half of the stable conductive point;
4.Wire feeding speed or amount of fusion
The smaller the diameter of the mig contact tips, the shorter the service life. For the same 300A current, the amount of filling (melting) per unit time of 1.2 and 1.6 welding wires is basically the same.
The welding wire length of 1.2 is twice that of 1.6, that is to say, the wear amount of the mig contact tips of 1.2 is almost twice that of the mig contact tips of 1.6 with the same current and the same time.
Assume that the conductive tips of 1.6 and 1.2 are both worn by 0.2mm, which is 12.5% of 1.6 and 16.7% of 1.2. The beating range of the welding wire of 1.2 is larger.
1. the procurement of chromium zirconium copper (CUCRZR),Tellurium copper
2. Alignment of welding wire
3. Conductive mouth must be tightened with pliers, only hand twist is not good, arc instability。
4. The gun cleaning station is normal and sprayed with anti-splashing silicone oil.
5. Generally, small voltage is used.Approximate formula 14+0.04* current, high voltage, high loss.
6. Always clean the wire feed line.
7. The quality of the wire is also decisive
8. The workpiece surface as clean as possible and less oil.
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