Industry's Push for Automated Fastening
Many fastening technologies exist for the joining of materials on the manufacturing line. Steel has traditionally been the material of choice with spot welding and/or threaded fastening as the dominant joining processes. This combination yields low manufacturing costs, but with the trade off of increased product weight. In recent years, many industries have progressively moved towards alternative materials to reduce weight, including aluminum, polymers, composites, carbon fiber or a combination of materials. Compared to steel, these alternative materials and their unique joining technologies carry higher costs. To offset the increased material and fastener costs, manufacturers are looking for ways to increase throughput of their production lines, prompting a change from manual fastening tools to fully automated solutions.
Fastening Technologies and Characteristics
The blind rivet process has traditionally been accomplished through manual drilling and fastening, where each rivet is placed into a pre-punched or pre-drilled hole prior to being secured in place with a manual tool. The Robo-Rivet blind fastening system removes both the need of a preexisting hole and intervention by an operator to manually fasten the rivet. Both operations are now combined into a fully automated process, providing a highly repeatable and efficient fastening solution.
The table below compares the characteristics of the fastening types commonly used for the joining lightweight materials, including the blind rivet, adhesive, mechanical clinch process, special welding techniques and different types of self-piercing fasteners. As compared to some of the other fastening technologies, blind rivets can carry a slightly higher consumable cost. The Robo-Rivet tool offsets the higher cost by improving the cycle time through automation of the fastening process. This increases the throughput of the production line while decreasing the overall manufacturing cost.
Advantages of Blind Rivets
- Holes are drilled in lieu of pierced - Prevents fractures in castings due to material grain structural deformation
- Blind rivets enable the ability to join dissimilar materials, including aluminum to steel or aluminum to carbon fiber
- Drilled hole is accurately aligned through all materials prior to fastening - Prevents sheet creep
- The blind rivet is a high clamping force fastener with a "pull up" motion - Pulls the parts together during the fastening process
- Drill and rivet tools are placed on one side of the part - Eliminates the need for a backing mandrel and creates additional degrees of freedom within the work cell for a robot
- The blind rivet fastening process eliminates the possibility of "boiling-off" adhesive - The hole is drilled in lieu of formed through plasticizing the material (melting through friction), as required with some self-piercing fasteners
- The back side of the rivet is blunt- Eliminates concerns for sharp edges that are present from some self-piecing fasteners
- The blind rivet can be used to fixture parts to allow for joining adhesive to cure or used solely as a structural fastener
Advantages of the Robo-Rivet Automated Fastening System