Stud welding is a technique that involves welding a metal fastener to another metal part using an arc of electricity to heat both parts. It is one of the many types of welding available to professionals across the engineering, construction, and manufacturing industries. Many favour this process due to its speed, reliability, and the powerful results it provides. Find out more about what stud welding involves, the different processes available, and the benefits of stud welding in comparison to other methods with our ultimate guide.
What is Stud Welding?
Engineers, manufacturers, and a range of other professionals use stud welding to effectively attach weld studs and other fasteners to sheet metals of varying materials and thicknesses. Operators attach weld studs to metal items as diverse as switches, buttons, circuit boards, cover plates, handles, hatches, machinery guards, pipes, legs, brackets, and fireproofing or insulating materials. The process is also suitable for decorative and consumer items such as signs, badges, nameplates, jewellery, and homeware.
Metals commonly involved in stud welding include stainless steel, mild steel, aluminium, aluminium alloy, copper, and brass. The studs themselves can be threaded, unthreaded, or internally threaded. Stud sizes range from 1mm to 25mm with specialist gun attachments.
Why Choose Stud Welding?
There are many benefits to choosing stud welding in comparison to other welding methods when it comes to attaching fasteners. Involving fewer steps for incredibly fast attachments, stud welding only requires access to one side of the parent material. It also causes no reverse marking in most applications. This means stud welds are also incredibly strong as you don’t have to punch and deburr holes, which can also cause issues with leaking and staining. In fact, the welded joint is stronger than the parent material or the original stud! Therefore, many professionals choose this process over others such as drilling, tapping, back welding, spot welding, and through bolting.
Stud Welding Processes
There are three main processes in stud welding: capacitor discharge, drawn arc, and short cycle (another form of arc stud welding). Each method is quite different in terms of studs, parent materials, power usage, and capabilities. Find out more about each method and how they compare:
Capacitor Discharge Stud Welding
The capacitor discharge process is one of the most common welding processes for manufacturing purposes. It involves placing a stud with a pip onto a thin gauge metal sheet, which is flat and clean. Charged capacitors discharge a high current pulse to melt the stud pip and produce an arc. The stud then forges to the sheet due to return spring pressure, providing total fusion across the flange.
The capacitor discharge process is compatible with materials from 0.7mm thickness and is suited to smaller diameter studs. Our capacitor discharge stud welding machines require a single phase 240/110-volt power source. This cost-effective and fast process suits aluminium, brass, mild steel, and stainless steel materials, plus it causes minimal reverse marking. It isn’t the most tolerant method; capacitor discharge welding isn’t suitable with curved or otherwise imperfect surfaces. However, in the right conditions CD stud welding is a fantastic choice for efficient, powerful, yet inexpensive stud attachment.
Drawn Arc Stud Welding
For parent materials above 2mm in thickness, drawn arc stud welding is the perfect method. The drawn arc method suits larger diameter fasteners (from 3 to 25mm). It provides a very controlled, neat weld fillet with strong penetrative results. Drawn arc also works with materials that have curvature or imperfections, making it a more flexible method than capacitor discharge. However, it does require a 415 volt, three-phase power source to achieve these results, so CD can still be the more viable choice for some operations. The drawn arc method also requires ferrules (ceramic shields) to contain the molten metal pool between stud and parent material. This adds extra steps to the workload.
In drawn arc, the operator places the stud onto the plate and triggers a pilot arc while the stud lifts to a pre-set height. The following main arc melts the weld end of the stud into a molten pool on the plate. Return pressure forges the stud into this pool. The surrounding ferrule shapes the fillet; the operator then chips away the ferrule. The drawn arc method is the only way of stud-welding large diameters and is suitable for multi-gun applications. The use of flux in the stud also keeps the weld area clean as it vaporizes and reacts with contaminants. Our largest drawn arc machine is the system 2700E, which can weld up 25mm diameter studs.
Short Cycle Stud Welding
Short cycle stud welding is like the drawn arc process in many respects but, unlike drawn arc, does not require ferrules or flux, instead using inert shielding gas. This makes it easier to automate operations as there are fewer steps. Short cycle is also generally faster than drawn arc. The process uses high currents to create more welds in less time, making it great for high-volume applications. However, it’s important to note that the short cycle method can create porous welds if used without shielding gas. This can make results slightly weaker than those from drawn arc welding. It also has less penetrative depth. It is therefore important to choose short cycle only when fast and inexpensive results are more important than strength.
When applicable, on the other hand, the short cycle process is a great choice for many operations. You can make use of CD welding studs, which tend to be cheaper than their DA counterparts. At the same time, you can also work on thicker materials than capacitor discharge setups, as well as metal sheets that feature curvature or imperfections. In many ways short cycle is the best of both worlds!
Automated Stud Welding
Automation has become an important consideration for a range of industries; automated machines can save time, reduce errors, and ultimately cut costs for companies within competitive fields. This is no less true for stud welding, where automation is more than possible for a variety of applications. We have several levels of automation available for our customers. This includes everything from automated part loading and unloading facilities to full robotic stud welding on 3D objects. Our CNC machines are incredibly powerful and accurate. We can provide multiple weld heads and controllers as well as automatic stud feed bowls for a constant workflow.
Stud Welding Videos
When it comes to machinery, seeing what can be done can be just as useful as reading up on methods and parts. We have an extensive video library of our machines. This includes clips of the capacitor discharge and drawn arc processes as well as automated and robotic stud welding systems. Check out the following playlists:
Capacitor Discharge Videos
See our capacitor discharge machines in action with our Contact and Lift Gap guns, as well as the capacitor discharge process with a robotic system.
View the full Capacitor Discharge playlist here.
Drawn Arc Videos
We have created videos for many of our specialist drawn arc controllers, including the 1200, 1600E, and 2000E systems. See each of the steps involved in the drawn arc process across the range.
View the full Drawn Arc playlist here.
Automated stud welding is where things get really interesting! We have videos for automatic systems including 2 axis and 4 axis machines, as well as a fully automated system in action (featuring loading and unloading stations).
View the full Automated playlist here.
Robotic stud welding is an important form of automation creating many opportunities for fully automated and fast manufacturing operations. These videos really show the incredible power of automation in the field.
View all of our Robotic videos here.
Got more questions about stud welding and what it can achieve for you? Get in touch with Taylor Studwelding today and we’ll be happy to provide more information.