An alternative to welding
Creating durable threads is crucial for ensuring the proper and safe assembly of components. On sheet metal, threads are formed by attaching specific threaded studs or inserts directly to the metal, providing precise male or female threads. Welding is one of the most commonly used and well-known methods. However, cold insertion of a threaded insert offers an excellent alternative and, in certain cases, is more suitable than welding due to its unique advantages.
WELDING STUDS ON SHEET METAL
Several welding techniques are used to attach studs, including capacitor discharge welding and short-cycle arc welding. Another method, arc welding with a ceramic ferrule, is primarily used in heavy construction but will be mentioned briefly here. Welding allows for quick and permanent attachment of a threaded stud to a wide variety of metals, such as copper-plated iron, stainless steel, and galvanized sheets. Short-cycle arc welding, with its short time (under 100 ms) and minimal penetration depth, is particularly suited for very thin sheets as it creates a narrow weld bead and limits heat input. This technique also provides stronger fastening than capacitor discharge welding and is widely applied in the automotive sector, especially for attaching studs to car bodies.
“COLD” INSTALLATION TECHNOLOGY
Cold installation of metal inserts with strong mechanical threads offers a cost-effective and high-performance alternative to welding. This process is done using a specialized press and works on all types of metal sheets with thicknesses starting from 0.5 mm. Because the process doesn’t damage surface coatings or paint, cold technology is ideal for use with steel, stainless steel, and galvanized or painted sheets. The strength of the thread depends on the type of fastener installed, not the properties of the sheet metal, resulting in high-performance captive threads, just like female threads. While welding requires only one free side of the sheet to attach the stud, some situations, like boxed sections, make welding more challenging. The use of fasteners overcomes this issue, enabling the creation of “blind” threads on sections only accessible from one side. Furthermore, with cold installation, cut edges or bends in the sheet metal pose no challenge, as inserts can be placed just tenths of a millimeter away from these areas. This gives designers more freedom in their projects, allowing for optimized dimensions of sheet metal parts that were previously limited by spacing or safety constraints.
MAINTAINING AESTHETICS AND FASTENING SEALS
When evaluating different joining methods, aesthetics is often an important consideration; whichever method is chosen, it’s essential that the opposite side of the stud installation remains free of deformation. With welding, no pre-drilling is needed, ensuring a watertight seal for the sheet metal. The same result can be achieved with cold fasteners, even when dealing with pressurized fluids. Lastly, it’s important to highlight that managing a cold installation system is technically simpler and more cost-effective, due to lower energy requirements. This process is also environmentally friendly, reducing harmful gas emissions and excess heat in the workplace.