In the world of stud welding, there is CD stud welding, and drawn-arc CD stud welding. Although these processes are very similar, there is a distinct difference that makes each welding process unique.
Used to weld smaller diameter fasteners to thin base metals, capacitor discharge (CD) stud welders use an electrostatic storage system as a power source. Welds studs are specially design for CD stud welding; they are engineered with a small projection, or tip, with high electrical resistance. When the trigger is pulled, a burst of electricity melts both the tip and a section of the base material. The spring in the gun then pushes the stud down into that molten metal, which solidifies quickly. The entire process takes place in 6 to 10 milliseconds.
This process limits the heat generation and has a low penetration level, so that studs can be welded to extremely thin and coated material. Unlike Arc stud welding, you do not need to use a ferrule or flux. The weld quality does depend on the geometric consistency of the stud's tip. If the tip is too small, the energy of the arc will melt the tip too quickly; if it is too large, the tip may not totally liquefy for complete fusion.
Drawn-arc capacitor discharge stud welding, however, uses the same principle of storing energy in capacitors, but does not require a stud with a special tip. Instead, the weld occurs by pulling the stud off the workpiece and initiating an electric arc between the stud and the plate. The arc melts the work piece and a spring plunges the stud down into the molten material, creating a strong weld.
Unlike conventional CD stud welding, its drawn-arc variant is a controlled process, meaning the operator can adjust the settings of power source to control the stud's drawing action as well as the energy put into the weld.
While drawn-arc CD stud welding can be controlled, it isn't a closed-loop process. If some unforeseen variation in stud size occurs, the system cannot improvise and compensate. Only the latest stud welding technology—inverter drawn-arc stud welding—can sense changes and compensate for them within a millisecond, to ensure the process uses the correct current and time for the stud actually being welded.
Sunbelt Stud Welding carries the best basic CDs, drawn-arc CD, and inverter drawn-arc stud welders in the industry. Whether you are looking to do highly manual or completely automated stud welding, Sunbelt is your supplier.
The experts at Sunbelt Stud Welding welcome inquiries concerning any stud welding process or equipment, 713-939-8903.