When it comes to resistance welding, the two options include the development of spot weld or projection weld studs. Typically, the projection weld is considered the superior option for many different types of applications as it provides for fewer variables that can impact the overall quality of the weld.
The process of creating a projection weld studs with a consistent quality in the weld is really in the formation of the projections. They need to be consistent and free from any type of fractures or irregularities. If these issues occur in the projections the heating of the surface will not be even and some components of the projection will collapse before others, leaving an uneven weld.
Improved Surface
Once advantage to using projection weld studs rather than spot welding is that there is a limited risk of heat damage to the exterior surface of the workpiece. This is particularly important with thinner metals used in fabrication where a clean, unblemished surface is important in the design and finished look of the item.
A good example of this would be in the food service industry. The stainless steel exteriors of cabinets and equipment need to be completely free from any heat blemishes or discolorations. While this welding process can be done on thinner metals, it is also a good option for thicker workpieces as well. As with most considerations, the specifics of the materials and the end use will be critical to know before selecting projection welding as the correct process.
This is possible, in part, because the process uses larger electrodes. This allows full coverage of the surface area of the stud, providing a clean, strong weld when done correctly. It is also important to carefully consider the placement of the projections based on the need to control spatter, particularly with threaded studs where spatter and distortion from heat is an essential consideration.
