Automated Screw Fastening
April 3rd, 2021
In Short
Fully automating the fastening process has been a challenging journey. Traditional automated screw fastening solutions struggled with workpiece variations and positional errors, often resulting in damaged workpieces and lower yield rates. These traditional solutions were also heavily reliant on custom modules and the precise positioning of screw fasteners, leading to elevated non-standard equipment usage and prolonged debugging and deployment cycles. If a workpiece was out of alignment, a traditional automated screw fastening robot would have a significant problem.
Flexiv’s adaptive robots, though, can simply initiate a detection algorithm that can intuitively ‘feel out’ the screw’s cavity. This approach results in enhanced product quality and increased production efficiency. Using a Rizon adaptive robot equipped with a standard off-the-shelf screw gun, screw fastening tasks can be completed without the need for additional force sensors or dedicated screw-feeding modules. Capitalizing on Rizon’s unique force-control response rate and employing a series of force-control strategies to compensate for vision errors or positional deviation, Flexiv can achieve error-free, high-precision fastening day in and day out. Simple to deploy and uniquely capable, a Rizon robot can complete screw fastening applications one day, pick and place tasks the next, and material abrasion jobs the day after. All this using off-the-shelf tools or Rizon’s dedicated Grav robotic gripper.
Enhanced Error Tolerance
Leveraging an adaptive robot’s 1kHz force-control response rate and a precise force resolution of 0.03 N, insertion force and torque can be reacted to and monitored in real-time via force-control strategies. These strategies, including force-controlled hole searching, constant force pressing, and thread entry alignment, remove a robot’s reliance on imprecise visual positioning and act as a compensation mechanism for workpiece position and orientation errors. Thanks to these features, Flexiv’s screw fastening solution offers exceptional reliability, accommodating millimeter-level position deviations, thus increasing first-pass yield.
Flexible Deployment and Faster Debugging
Paired with Flexiv’s Meta-operation Primitive software package, deployment time is significantly reduced, and the skill-based barrier to entry for creating custom screw fastening tasks is removed. Featuring a simple-to-use and understand drag-and-drop programming interface, deployment and debugging time is reduced by at least 20% compared to traditional solutions.
Adaptable and Customizable
Leveraging its seven degrees of freedom and full-body force control, a Rizon adaptive robot can accurately replicate the fastening techniques employed by human workers. Thanks to unrestricted fastening angles, it can also complete vertical and lateral fastening tasks maximizing its potential use cases. If a workpiece is particularly large, or the fastening must be accomplished as quickly as possible, an additional Rizon adaptive arm can be used to halve the workload and double the throughput speed.
