Manufacturers in many industries are reshoring their assembly lines. Several factors are behind this phenomenon, including the ability to automate assembly tasks that traditionally used manual or semiautomated fastening equipment.
A few years ago, screwdriving was synonymous with large production volumes, long production runs and few changes to assemblies. Today, flexibility is the watchword, and robots are enabling manufacturers to cope with the challenge of high-mix, low-volume assembly without breaking the bank.
Robotic screwdriving differs from more traditional applications, such as fixed or handheld screwdriving. For instance, robots make it easy to do quick changeovers and run small, varying size batches of related assemblies.
In addition, robots can drive screws from all directions, sometimes with varying torque requirements. They also have the ability to drive different sizes of screws using various feeders for each type of fastener. Manufacturers can achieve higher cycles per screwdriver spindle and faster cycle time per screw, while improving quality.
Traditionally, robotic screwdriving was associated with large bolts used in powertrain assembly. But, new technology, such as controls, software and vision systems, now allows assemblers to insert and tighten small screws that are used in many other applications, including electronics and medical devices.
“Robotics is a more accepted method of automation than it was five years ago,” says Patrick Laughter, engineering man-ager at DENSO Robotics. “Also, the automated screwdriver companies are designing their controls to communicate more easily with the robot manufacturers’ controls.”
While the auto industry continues to be the biggest user of robotic screwdriving, other manufacturers are embracing the technology. “They’re looking to robotics to assemble everything from toasters, consumer electronics and mobile devices to surgical hardware—anything that requires fastening two pieces of hardware together,” Laughter points out.
“Our requests for robotic applications have increased,” adds Neil Maniccia, global product group manager for ASG Preci-sion Fastening, a division of Jergens Inc.
“When handling small fasteners, [this technology] can reduce the [risk] of fasteners being dropped into [an assembly]. In addition, it can increase cycle time and allow the product to be fastened in the proper sequence.”
According to Kevin Buckner, design engineer at Design Tool Inc., several trends are driving the increased use of robotic fastening. “These factors include lower cost of robotics, increased capacity and capability in robots, and increased use of automation to improve productivity and maintain a lean production environment,” he explains. “Many companies are using robotic systems to assemble components in either standalone stations or fully integrated into an assembly line.”
Boris Baeumler, applications engineer at DEPRAG Inc., says manufacturers are shifting to robotics from multispindle screwdriving equipment. “With new developments in screwdriving technology, I see potential for further activity. [That’s because] robotic stations are easier and less expensive to retool. The cost of robots is also continuously decreasing, while capability is increasing.
“Multiple products with different hole patterns can be run on the same line,” Baeumler points out. “Reduced cycle time requirements allow for screws to be driven in series rather than in parallel.”