Joining in high production environments
- Published: October 16, 2016
Coldwater Machine Co.'s SpotMeld is a robotic joining system with new automated tool change capability.
Capable of volumes required for high production environments, the SpotMeld solution enables the joining of aluminum (1000 – 7000 series), magnesium, non-ferrous and dissimilar sheet materials, which has proved problematic with traditional joining technologies. SpotMeld systems can be mounted on any industrial robot or retrofit for replacement of existing processes such as resistance spot welding, laser welding and riveting.
The process is based on Refill Friction Stir Spot Welding (RFSSW) technology. It uses rotational friction to heat the materials along with pressure to forge together the parts using wear-resistant tooling to join two or more surfaces. In addition to joining lightweight materials, benefits include high quality solid state joints that are near original material strength, a small heat affected zone, consistency in weld duplication and faster weld times -- as well as being environmentally cleaner and safer with no filler material, spatter, smoke, radiation or shield gasses.
As compared to laser welding and other aluminum-joining techniques, SpotMeld is an easier process to fixture and the automated tool change capability saves significant time as compared to self-piercing rivet changeover, claims the company. Additionally, a variety of weld recipes can be used on demand by the robot controller, which results in a very flexible production system.
The company says a major advantage of the Coldwater system is that the tool doesn’t fully penetrate through the bottom sheet, leaving a smooth surface with potential for use on exterior body panels. Alternative friction spot welding techniques typically use a solid pin that does not retract leaving a surface that has some material off-set on it as well as a 3 to 4 mm hole in the center of the weld.