Welding is vital to many industries, from skyscraper construction to car manufacturing. And among the various welding techniques available, MMA welding or Manual Metal Arc Welding stands out for its versatility and efficiency.
Join us as our industrial welding professionals in Quebec present MMA welding (also called stick welding), explaining how it works, its benefits, and why it remains the technique of choice for professionals and hobbyists worldwide.
MMA welding definition
Welding dates back to ancient times, and welding techniques have been constantly refined and adapted over the centuries according to the changing needs of industry. MMA welding occupies a prominent place among the many welding techniques that exist today.
MMA stands for “Manual Metal Arc”. As the name suggests, this is a manual welding technique that relies on an electric arc to fuse metals. “Manual” refers to the fact that the welder will guide the electrode by hand, “Metal” refers to the base material used, and “Arc” refers to the electrical phenomenon that generates the heat required to fuse the metals.
Examples of MMA welding projects
- Pipeline construction: MMA welding is often used to join sections of pipe with watertight, pressure-resistant welds.
- Agricultural machinery repair: Agricultural equipment is often subjected to hard use. MMA welding is a good choice for repairing these tools, as it produces exceptionally sturdy welds.
- Metal furniture manufacturing: MMA welding is used to create sturdy, attractive furniture or every kind, from chairs to tables.
- Shipbuilding: In shipyards, trained professionals use MMA welding to join large sections of ship hulls and other marine structures.
How does MMA welding work?
MMA stick welding involves a symphony of elements working in concert to create a strong metallic bond. To really understand how it works, let’s break down the process, step by step.
Creating the arc
It all starts with the electric arc. When the electrode is brought close to the workpiece and a current is applied, it creates a nearly complete circuit. By moving the electrode slightly away from the workpiece, a gap is formed, where the electric arc appears. This spark generates a tremendous amount of heat, which melts the metal on contact.
Role of the coated electrode
The electrode plays a dual role in this process. First, it acts as a conduit for the current, allowing the electric arc to form. Second, as it melts, it provides the filler metal needed to form the weld. But that’s not all: the electrode coating is crucial. As it melts, it generates gases that surround the weld zone, creating a protective atmosphere. This contributes to the formation of a layer of slag on the weld, which can be removed after cooling.
Protection against oxidation and contamination
It is important to protect the weld, otherwise the molten metal will be exposed to oxygen in the air, which could lead to rapid oxidation and compromise weld quality. Other airborne contaminants, such as nitrogen, can also affect the weld. The protective atmosphere generated by the electrode coating prevents these harmful elements from coming into contact with the molten metal, ensuring a clean, strong and long-lasting weld.
Advantages of MMA welding
Despite the emergence of new welding technologies and techniques (such as MIG/MAG welding and laser welding), MMA welding remains a preferred choice for many professionals. But what makes this process so attractive? Here are some of the major advantages of MMA welding.
One of the major advantages of MMA welding is its versatility. It can be used on a variety of metals, from common steels to more specialized alloys. Whether you’re working on mild steel, stainless steel, cast iron or even aluminum, MMA welding will do the job well. If you need help with projects that involve working with different types of materials, contact us!
Portable and easy to use
Unlike some welding processes that require heavy, bulky equipment, MMA welding machines are often compact and designed to be easily transportable. This makes them ideal for doing welding work on site or in confined spaces. What’s more, the simplicity of MMA welding makes it accessible even to those who are relatively new to welding.
However, if you have professional-level welding needs, it’s always advisable to call in an industrial mechanic.
Cost-effective and efficient for a variety of projects
MMA welding offers excellent value for money. The equipment required is generally less expensive than would be necessary for other, more complex welding processes. In addition, MMA welding is efficient, making it ideal for both small-scale projects and large-scale construction work.
The ability to produce strong, durable welds without the need for expensive equipment or shielding gases makes MMA welding a cost-effective option for many companies wishing to carry out industrial subcontracting.
Disadvantages of MMA welding
Although MMA welding offers many advantages, it also presents certain limitations and challenges. Here are some of the main disadvantages associated with MMA welding.
Limitations related to speed and delicate materials
MMA welding is not always the fastest process. Compared to other techniques, such as MIG welding, MMA can be slower, especially for large projects. MMA welding can also present challenges when it comes to welding very thin materials. The intense heat generated by the electric arc can deform or even burn more delicate metals.
Challenges of slag removal
One of the most difficult aspects of MMA welding is slag removal. After welding, the slag (the protective layer that forms on the weld surface) must be carefully removed to reveal the clean weld beneath. This extra step can add time to the overall process, and if not carried out correctly, can affect the quality and appearance of the weld.
Comparison with other welding methods
When MMA welding is compared to other methods, certain disadvantages become apparent. For example, unlike TIG welding, MMA welding does not always produce clean, attractive welds.
Also, while MIG welding can be automated for large-scale projects, MMA welding remains primarily a manual process, which can limit its effectiveness for large-scale production.
MMA welding equipment
MMA welding requires specific equipment to guarantee quality welding and keep welders safe.
MMA welding machines
At the heart of the MMA welding process is the welding machine itself. These machines, often referred to as MMA welding units, are designed to supply the current needed to create the electric arc between the electrode and the workpiece. They can be powered by alternating current (AC) or direct current (DC), each with its own advantages depending on the type of metal being welded and other specifics of the job.
Modern welding machines are often equipped with advanced features, such as current regulators, to enable precise adjustments and guarantee optimum welding results.
Electrodes and electrode selection
The electrode is a central element of MMA welding. These metal “rods”, coated with a protective flux, serve both as a heat source (via the electric arc) and as filler material for the weld.
The choice of electrode depends on the type of metal to be welded, the thickness of the material and the desired properties of the weld. There are a variety of electrodes available, each designed for specific applications, and proper selection is essential for optimal results.
Safety: personal protective equipment
Welding, though rewarding, can be dangerous without taking the proper precautions. During MMA welding, the operator is exposed to intense light, sparks, spatters and heat. Consequently, it is extremely important to wear suitable personal protective equipment (PPE). This includes:
- Welding mask: to protect the eyes and face from intense arc light and sparks
- Welding gloves: designed to resist heat and protect the hands from burns
- Fireproof clothing: to protect the skin from sparks and heat
- Safety footwear: to protect the feet from hot, heavy objects
HARtech is your partner for industrial welding projects
MMA welding, with its many advantages, is an essential technique in the world of industrial welding. But as with any method, the quality of the result depends largely on the expertise of the welder who applies it.
Whether you’re looking for a solution to a complex project, or need expert advice to optimize your welding processes, HARtech is here to help. We understand the subtly different characteristics of every project, and are committed to delivering top quality results.
Don’t leave your welding projects in the hands of just anyone. Trust HARtech, Quebec’s true experts in industrial welding. Contact us today to discover how we can turn your welding challenges into welding success stories.