Riveting machines are designed to apply rivets to materials, such as sheet metal, to produce fasteners that bind the parts together. They range from hand-held handheld riveting guns that are manually operated to multi-head automated riveting tools that are electrically, pneumatically or hydraulically actuated. Riveting machine processes are categorized into three broad groups: impact, non-impact and self-piercing riveting (SPR).
In impact riveting, the rivet is deformed by being driven downwards from the head of the gun into a forming tool called a rollset. This action forces the end of the rivet to deform in the process, creating a strong binding between the materials. Impact riveting is a double-sided process and therefore requires access to both sides of the material stack. The process is highly repeatable and can be robot-mounted for use in a flow-line. The cycle time is short and comparable to spot-welding, although the rivet ends are more susceptible to fatigue failure than other types of rivets.
The non-impact riveting process involves a series of sequential steps to form the rivet head and bind the materials together. This method is used for brittle materials or those that are difficult to heat, such as aluminum. The process is more accurate than other riveting methods and produces a smoother head finish. However, this process can be slow and labor intensive.
For high-volume production applications that require a reliable, repeatable riveting process, the self-piercing riveting machine is an excellent choice. This riveting process is characterized by using a self-piercing rivet (SPR) to create a joint without needing to pre-drill or punch holes into the materials. The SPR is a specialized, nail-like rivet that is inserted through the material stack and cold-formed into a riveting head to hold the materials in place.
A riveting machine can be built to include dedicated SPR process monitoring systems that are able to detect problems such as a rivet failing to deform or the forming force being too low. These systems utilize dedicated sensors that monitor the setting force and punch movement throughout the riveting process, generating a force-displacement curve which is then compared to a trained reference curve. If the curve fits within a defined tolerance, the rivet is considered pass and the system is safe to continue operation; otherwise, the process is flagged for attention or even halted.
Automating the riveting process can increase throughput and quality for many assembly operations. Stryver has experience building automated riveting systems that include a rivet feeder with poke yokes, part validation and data collection to confirm rivets are fully seated, as well as robotic riveting systems that can be programmed to carry the rivet gun to each rivet location. Contact us to discuss your specific application and assembly process requirements. We will be happy to recommend the best riveting machine for your needs.
