Something Your Should Know about MMA
Shielded metal arc welding (SMAW), also known as manual metal arc welding (MMA or MMAW), flux shielded arc welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode covered with a flux to lay the weld. An electric current, in the form of either alternating current or direct current from a welding power supply, is used to form an electric arc between the electrode and the metals to be joined. The work piece and the electrode melts forming a pool of molten metal (weld pool) that cools to form a joint. As the weld is laid, the flux coating of the electrode disintegrates, giving off vapors that serve as a shielding gas and providing a layer of slag, both of which protect the weld area from atmospheric contamination. Because of the versatility of the process and the simplicity of its equipment and operation, shielded metal arc welding is one of the world's first and most popular welding processes. It dominates other welding processes in the maintenance and repair industry, and though flux-cored arc welding is growing in popularity, SMAW continues to be used extensively in the construction of heavy steel structures and in industrial fabrication. The process is used primarily to weld iron and steels (including stainless steel) but aluminium, nickel and copper alloys can also be welded with this method.
Some Important Functions Added in Punair Led Smart Welder
At the beginning of the work, electronic products provide additional current pulses, which help ignite the arc which is called Hot Start function. If the electrode is too close to the details, the Arc Force function increases the welding current and prevents sticking. During the viscous process, the current decreases or closes, but the possibility of "adhesion" of electrodes (Anti Stick function) is not included.Also,to ensure the safety of welder，VRD is added with concerns！ Hot start: The function of hot start is to add a certain amount of current on the basis of welding current at the moment of arc starting, so as to prevent welding rod from sticking and improve the success rate of arc starting. Like Arc force, the welding machine with small current output usually has a fixed thermal arc current. The thermal arc current of the welding machine below 300A is about 30-50A, and that of 315A and 400A is about 70-80A. Welding machine with high rated output current has the function of adjusting hot start current. VRD function: VRD is an anti shock device, which makes the output voltage of the welding machine very low (within the safe voltage) when no load, and returns to normal when welding. When the no load voltage is very low (about a dozen volts) and the welding can work normally, we can say the VRD is controlled. The VRD function can be selected by the VRD switch on the panel. ARC FORCE: ARC FORCE is when the electrode and the work piece are about to stick together (that is, the arc distance is very short, the arc voltage changes very small), the welding current will automatically increase, so that the welding rod melts, rather than sticking to the work piece, affecting the welding process and welding quality. Another function of ARC FORCE is to reduce arc voltage and increase welding current, thus ensuring constant output power. For welders with lower rated output current, a fixed ARC FORCE is usually added to the circuit, while some welders with higher rated output current can adjust the thrust current on the panel.