Welding fastening are essential in many industries, including sheet metal and boiler making. Used to ensure strong, durable assemblies, capacitor discharge and drawn arc fastening methods are distinguished by their unique characteristics.

Capacitor discharge minimizes the risk of deformation thanks to a rapid, intense electrical discharge. This enables welding to be completed in milliseconds. The drawn arc, on the other hand, is suitable for thicker materials (2 mm and over). This technique uses an electric arc to create a strong, durable weld capable of withstanding high forces.

In this article, we explore these two techniques of welding fastening in detail, their advantages and our range for each method.

Capacitor discharge weld : the fastest welding method

Capacitor discharge welding is a fast and efficient method. It is particularly suited to production environments where time is of the essence. The process involves using a high-intensity electrical discharge to weld a stud or other fastener to a metal surface.

How does capacitor discharge welding work?

Capacitor discharge-welded components have a small pin about 0.8mm in diameter and 0.9mm high, ensuring optimum distance from the metal sheet. During soldering, the current vaporizes the ignition pin. An arc is then formed in a fraction of a second, superficially melting the material. The pressure of the gun’s spring then presses the component into the molten bath, guaranteeing a perfect weld.

The welding station stores the current in capacitors, releasing up to several million KVA amperes in just a few milliseconds to complete the weld. The component can be positioned by tracing or centering using a template mounted on the gun.

What are the advantages of capacitor discharge welding?

Capacitor discharge welding stands out for its increased speed, with an execution time of just a few milliseconds. This means extremely high production rates. The process is remarkably simple, since it eliminates the need for drilling or tapping, making installation considerably simpler. This speed also makes it possible to weld in air without oxidizing the molten bath.

What’s more, it guarantees optimum precision, reducing the risk of deformation of thin parts or sheet metal, and ensuring a clean, precise assembly.

When to use capacitor discharge welding rather than drawn-arc welding?

● Thin sheet metal : The capacitor discharge method is ideal for sheet metal less than 2 mm thick, as it minimizes the risk of material deformation. Capacitor discharge guarantees clean, precise fastening on thinner materials.

● Fast production : Capacitor discharge is perfect for high-speed production lines where every millisecond counts. The extremely fast process increases efficiency and reduces production times.

● Simplicity and economy : For projects where speed and ease of implementation are priorities, capacitor discharge is the best choice. It requires less preparation and equipment than the drawn arc. This translates into savings in terms of costs and resources.

Which parts should be used for capacitor discharge welding?

Pulse arc welding : the most reliable method

Pull-arc welding is a welding fastening method that offers greater parameter control and excellent reliability. It is particularly suited to applications requiring high force transmission and robust fastening.

How does pull-arc welding work?

An electric arc is generated between the stud and the surface to be welded, causing the two materials to fuse together. Once the arc time has elapsed, the stud is plunged into the molten bath. It quickly solidifies, guaranteeing a strong, durable weld.

What are the advantages of arc welding?

The arc-welded fastener features a range of stud diameters up to 25mm. It offers robustness capable of withstanding considerable forces. This method also ensures unrivalled precision and allows meticulous control of the weld, minimizing the risk of defects.

What’s more, it is highly adaptable, being compatible with a wide range of material thicknesses, including sheet metal 2 mm thick or more.

When to use the arc-welded fastener rather than the capacitor discharge method?

● Thicker materials : the drawn arc method is ideal for thicker materials (2 mm and over), offering a strong, durable weld. Unlike capacitor discharge, the drawn arc generates sufficient heat to guarantee robust fastening on thicker materials.

● Demanding applications : Perfect for projects requiring high force transmission and increased robustness. These can be found in structural steel construction and heavy-duty industrial applications.

● Precision and control : For projects requiring precise weld control and reduced risk of defects, the drawn-arc method enables finer adjustment.

Neutral gas or ceramic ring: which option to choose for drawn arc welding?

● Neutral gas (gas shielding) : Neutral gas is used to protect the weld from oxidation during the process. This type of welding is ideal for controlled environments and applications requiring a clean, precise finish. It is also possible to weld aluminum studs under suitable neutral gas.

● Ceramic ring : serves to contain and concentrate welding heat, ensuring efficient fusion and reducing spatter. This type of welding is often used for stud diameters greater than 12 mm and applications where movement is required.

● Full-diameter bases : Maximize strength for optimum fastening. They are used when strength is a priority, for example in structures where loads are high.

● Reduced bases : They minimize the welding collar, enabling more precise assembly. They are ideal for applications requiring a discreet, clean weld. For example, in aesthetic or precision components.

Which parts to use for drawn-arc welding?

● Welding studs : Available in a range of materials (mild steel and stainless steel) and sizes (M6 to M16). These studs are an economical and efficient solution for sheet metal fastening.

● Welding sockets : Available in a range of materials (stainless steel and inox) and sizes (M6 to M10). These sockets are a solution for applications where safety and reliability are paramount.

It’s important to note that capacitor discharge and short arc processes lend themselves well to automatic machine production.

By choosing the right welding fastening method and quality products, you optimize the durability and safety of your assemblies. They guarantee the success of your projects.

For more information, consult our experts. Find all our products on the welding fastening page.