Large parts are usually manufactured in bits before joining them together to make a whole. Welding creates a permanent joint between two or more metals. The use of welding is not limited to the initial manufacturing of components, you can use it for equipment repair and machine maintenance.
There are many types of welding in manufacturing with the TIG and MIG techniques being the most common. Though they both produce high-quality and neat welds, they are not the same. Before using any welding process, it is important to understand how it works to make the most of it. This article will explain what MIG and TIG welding are, their advantages and disadvantages, and the differences between the two techniques.
What is TIG (Tungsten Inert Gas) Welding
You can also refer to it as Gas Tungsten Arc Welding (GTAW) or heliarc welding. TIG welding uses a non-consumable tungsten electrode to produce a weld. An electric current, usually DC, forms an arc between the base metal and the electrode. The arc generates heat and joins the metals together. Note that you may choose to or not to weld using a filler material. The filler metal is a separate entity that is added using a filler rod to reinforce the joint.
When carrying out TIG welding, it is important to first clean off all debris and contaminants from the base metal. For this step, you can use a solvent or a clean dry cloth. Thereafter, start the machine and modify the settings based on the material you are working with. Place the touch at 70 to 80 degrees on the workpiece and move it in a controlled manner. After welding, inspect for flaws and make necessary adjustments if needed. It is important to use shielding gases which can be argon or helium to prevent unwanted reactions during welding.
Pros and Cons of TIG Welding
TIG welding is the first choice for many applications because it produces a strong weld bead and does not spatter. The following are some advantages of TIG welding
Precise Control
With TIG welding, you have total control over the amount of filler added, heat input, welding speed, and other parameters. Furthermore, the electric arc is transparent and you can see through it easily. Hence, you can detect mistakes and make real-time adjustments quickly. This is important when working with thin and delicate materials.
No Flux Required
In TIG welding, you do not need to add a mixture of various materials to protect the weld pool from atmospheric contaminants. These minerals and chemicals can introduce impurities or leave a residue that requires cleaning. It can also trap slags in the weld or between layers which affects the overall results.
Flexibility
You can use a TIG welder in many positions and any angle. Many TIG welders are compact and portable and you can weld a part vertically or horizontally. This feature makes TIG welding useful for joining heavy machinery and tools in various locations.
Material Compatibility
You can safely use TIG welding to join many types of metals such as aluminum, stainless steel, copper, and titanium. Note that various metals require unique considerations. For instance, you need to properly control the heat input for metals that have high thermal conductivity like aluminum.
TIG welding has many benefits when compared to other techniques. However, it comes with some shortcomings. Below are factors you should consider before using a TIG welder for your project
Skill Intensive
You need more than basic technical skills to operate a TIG welder efficiently. You must have high proficiency in manual dexterity with steady hands. Good hand-eye coordination is necessary to create smooth and strong weld beads. You should be able to feed in the filler material at an optimal rate and control heat input simultaneously.
Slower Process
TIG welding is slower than most other welding operations. It will take you a long time to complete a welding cycle. This is because the process is mostly manual and requires you to be meticulous. Additionally, it is better used for thinner materials. Thin metals require a slower welding speed to prevent overheating.
What is MIG (Metal Inert Gas) Welding
MIG welding is often called Gas Metal Arc Welding (GMAW) or wire welding. In this process, a thin wire acts as the electrode and is fed from a spool mounted on a gun. As you pull the trigger on the welding gun, the wire is added continuously. As a result, an electric arc is formed between the metal wire electrode and the workpiece. This melts the base metals locally above their melting to form a weld pool. The metal parts then fuse as they solidify.
This process uses protective gasses that flow out of the nozzle to prevent airborne contaminants such as oxygen and water vapor. The shielding gas is usually 75% argon and 25% CO2. MIG welding is versatile as you can use it for both thick and thin parts. This process is fast and the resulting weld is neat and may not need further processing. Note that the current is usually DC. However, it is also possible to use AC when you are continuously switching between negative and positive currents.
Pros and Cons of MIG Welding
MIG welding can either be automatic or semi-automatic. You should choose it over other welding techniques because of the following reasons.
High Productivity
MIG welding is an efficient process that increases productivity in many manufacturing industries. It is fast because the wire electrode is continuously fed from a spool-gun MIG touch. These features reduce start and stop actions during an operation. Furthermore, it is fast and suitable for large scale manufacturing.
Versatility
MIG welding is a versatile process that can work on various metals and alloys to meet the diverse needs of manufacturing industries. You can use it to join steel, aluminum, titanium, nickel, and even copper. This welding technique is also the method of choice when joining dissimilar materials. Note that the metals you are using must have similar melting points to get the best result.
Beginner-Friendly
One of the most important advantages of MIG welding is its simplicity. It is easy to learn and use a MIG welder even for individuals without prior welding experience. It requires pulling the trigger to start and end the operation.
Weld Quality
MIG welding uses shielding gas to prevent oxygen from entering the weld pool. As a result, the final welds are of very high quality. The seams are clean and do not have holes that can compromise strength. Additionally, they are smooth and deeply penetrate to fuse the base metals perfectly.
Despite their many benefits, MIG welding comes with some limitations you should be aware of. The major drawbacks of MIG welding are the wind problem and the high cost of setup
Wind Problem
It is not advisable to use MIG welding in windy conditions. Contents of the wind can react with the weld pool. This can compromise the quality of the weld or lead to irregularities. Note that you should always carry out MIG welding in a controlled environment free from wind or rain.
Cost
The cost of MIG welding is on the high side. The cost covers the machine itself, shielding gas, electrodes, and nozzles. It is better to use MIG welding when working on a large scale. This way you are sure to get a high return on investment.
TIG Welding Vs MIG Welding
TIG and MIG welding are both arc welding processes that use electricity and an electrode to join pieces of metals together. Though they produce similar results, MIG and TIG welding differ in many ways. The table below discusses the major differences between TIG and MIG welding.
| Parameters | TIG Welding | MIG Welding |
| Electrode Used | TIG welding uses a non-consumable tungsten electrode that remains unchanged after the process. | MIG welding uses a consumable metal electrode that gets consumed in the process. Hence, you have to replace it from time to time |
| Filler Material | TIG welding uses an external filler material to join the metals. | MIG welding does not require a separate material to fill the weld joint. |
| Shielding Gas | TIG welding utilizes pure argon as the shielding gas to prevent contamination of the weld pool. | The shielding gas in MIG welding is usually argon, CO2, or a combination of both. |
| Weld Quality | TIG welds have a better quality. They are smoother and aesthetically pleasing because you have better control of the heat input. | MIG welding produces clean and high-quality welds. The joints are strong and can last for a long time. |
| Set up and Equipment | TIG welding uses more complex equipment that makes the setting up process time-consuming. | It is easier and less complex to set up a MIG welding system. |
| Skill Requirements | TIG welding needs expertise and a high skill level. The operator must have precise control over the process to get the best results. | MIG welding requires a basic skill level to operate. As a novice or beginner in welding, experts advise you to start with MIG welding before progressing. |
| Speed | TIG welding takes a considerable amount of time because it requires a slower travel speed. | This process is faster and increases overall productivity because the electrode acts as the filler material. |
| Material Thickness | TIG welding provides better welds for thin metals. | MIG welding penetrates thicker materials with ease |
| Applications | TIG welding has applications in fabricating arts and crafts, making automobile components, repairing food processing and packaging equipment, and fusing aerospace parts. | You can use MIG welding for sheet metal fabrication, building and repair of automotives, welding of pipes, and construction of bridges. |
Conclusion
For sheet metal fabricating, none is considered the best when it comes to MIG and TIG welding. Each technique has different advantages, disadvantages, and applications in manufacturing industries. Before using any, you need to consider many factors such as the thickness of the workpiece, lead time, and the required surface finish.
MIG welding may be the most appropriate for novices when working with thick metals and if the finish does not have to be aesthetically pleasing. However, go for TIG welding if the workpiece is thick and the final weld has to be clean and precise.
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