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MIG Welding 1 Maintain 1/4-3/8 inch of shank extension (the length of wire extending from the gun tip). 2 Use small diameter wire when welding thin plates； Use large diameter wire and a high current welder when welding thick plates. Check the specific performance of the welding machine recommended. 3 Use the correct welding wire to weld the workpiece. Stainless steel welding wire welds stainless steel, aluminum welding wire welds aluminum, and steel welding wire joins steel. 4 Use the correct shielding gas. Carbon dioxide is very suitable for welding steel, but the temperature may be too high for welding thin plates. A mixture of 75% argon and 25% carbon dioxide should be used to weld thinner materials. For welding aluminum, only argon gas can be used. When welding steel, you can also use a mixture of 3 gases (helium + argon + carbon dioxide). 5. To achieve the best effect of controlling the weld bead, keep the welding wire directly aligned with the joining edge of the molten pool. 6. When the welding operation is in an abnormal position (vertical welding, horizontal welding, overhead welding), the molten pool should be kept small to achieve optimal control of the weld bead, and the smallest diameter welding wire should be used as much as possible. 7. Make sure the wire size you use matches the cap tip, liner, and drive roller. 8. Clean the welding gun liner and driving roller frequently to keep the welding gun nozzle free of spatter. If the welding gun mouth is clogged or the wire feed is not smooth, replace it. 9. Try to keep the welding gun straight when welding to avoid wire feeding problems. 10 Use both hands at the same time during welding operations to ensure the stability of the welding gun, and do so whenever possible. (This also applies to rod welding, TIG welding and plasma cutting) 11 Adjust the tightness of the wire spool and drive roller of the wire feeder to just enough for wire feeding, not too tight. 12. When the welding wire is not in use, keep it in a clean and dry place to avoid contamination that may affect the welding effect. 13 Use DC reverse polarity DCEP power supply. 14 The drag (pull) welding gun technique can obtain deeper penetration and narrower welds. The push gun technique produces shallower penetration and wider welds. Aluminum welding 1. The best type of welding gun for aluminum is a brushed welding gun. If you can't use this type of welding gun, try to use the shortest welding gun to keep the welding gun straight. ； Only argon can be used as shielding gas ； Only use the push gun method when welding aluminum. 2. If you find that you have wire feeding problems, you can try a conductive tip that is one size larger than the soldering wire. 3． The most commonly used wire when welding aluminum is the softer standard wire. The other type is harder (easier to feed wire) and is mainly used in welding operations that require higher hardness and strength. 4. Before starting welding, it is necessary to remove the oxide layer on the surface of the aluminum material, and use a special stainless steel brush to remove the oxide layer. 5. Fill the crater at the end of welding to prevent cracks. One way to do this is to leave the welding gun in the molten puddle for a few seconds after welding. Self-protected flux cored wire welding 1. Use the pull (or drag) gun technique when welding. 2. Keep the welding wire clean and dry to achieve the best welding results. 3． This type of welding is similar to stick welding in that the slag layer on the surface of the weld must be cleaned after the welding is completed. When cleaning slag, you can use a slag hammer and wire brush. 4. Self-shielded flux cored wire welding does not require extra shielding gas containers. (The protective agent is inside the welding wire). This feature makes it very suitable for use in outdoor operations, because the protective gas is easily blown away when used outdoors. 5. Self-shielded flux cored wire welding is more difficult than MIG welding when welding thin plates. TIG welding 1． Ideal for thin sheet welding - a clean welding process results in a beautiful weld appearance. 2. Argon is used as a protective gas when welding steel and aluminum. 3． Use DC Positive Polarity (DCEN) to weld steel and stainless steel and use AC to weld aluminum. 4. The push gun technique has always been used in TIG welding. 5. Match the size of the tungsten electrode to the size of the cap tip. 6. Welding Aluminum - Pure tungsten electrodes should be used. In this way, tungsten can easily form a spherical tip during AC welding. 7. Welding steel and stainless steel - Tungsten electrodes containing 2% thorium should be used. When DC positive electrode welding, the tungsten electrode should be sharpened for electrode welding 1. Most of the time the drag gun technique is used. 2. Be prepared to prevent welding slag from splashing. 3． Keep the welding rod clean and dry - follow the manufacturer's recommendations. 4. melt through: Negative polarity DC - maximum penetration, AC - medium penetration (may also have more spatter), positive polarity DC - minimum penetration. Plasma cutting 1. A clean, dry, and oil-free air environment is very important. 2. Maintain the specified air pressure (higher air pressure may not necessarily provide better results) 3. Gently touch the cutting torch to the surface of the workpiece. 4. When starting to cut, start cutting from the end of the workpiece, and make sure that the arc is completely penetrated before cutting further. 5. After the cut is complete, pause where it ends to ensure complete disconnection. 6. The cutting torch should be kept at a perpendicular angle to the workpiece. 7. The working cable should be connected to the workpiece as tightly as possible. 8. If you can see the arc coming out of the bottom of the workpiece and moving at the correct speed, the cut will go smoothly. Resistance welding 1. Resistance welding is not suitable for welding aluminum, copper or copper alloys. And only used for welding steel and stainless steel. 2. For greater heat (current output), shorter electrode arms should be used. 3． If it is a welder without heat control function, the length of the electrode arm should be used for control. For example, longer electrode arms are used when welding thin plates that require low heat. 4. Be aware that longer electrode arms may bend, and you may also lose pressure on the weld. 5. Make sure there are no gaps between the welding workpieces, otherwise the welding effect will be greatly affected. 6. Keep both electrode arms aligned so that the electrodes are aligned with each other. Also, keep the pressure adjusted appropriately, not too much or too little. 7. If you need a certain side of the workpiece to look good after welding, you can grind (machine) that side of the electrode. 8. Clean the electrodes frequently, otherwise the output (current) will decrease. Appropriate protective covers should also be worn on the electrodes.