Coaxial Squeeze Riveter

The coaxial squeeze riveter is a new type of all-electric riveting machine recently developed by Electroimpact. At the core of the process is a servomotor-driven screw which provides the high thrust forces needed to upset rivets and press in bolts. The result is precise and accurate control of the riveting process which far surpasses older riveting technologies such as hydraulics and EMR.

The coaxial riveter is optimized for the installation of fasteners widely used in the assembly of metallic fuselage panels, most commonly:

Because the head design has been optimized for just these specific fasteners, we have been able to eliminate much of the complexity and expense that have become commonplace with large CNC automated fastening systems in the aerospace industry, and as a result can offer this system at a very competitive price point. The simplified nature of the design also leads to increased reliability, reduced downtime, easier and less frequent maintenance, and thus an overall lower total cost of ownership beyond the initial sticker price.

The first prototype coaxial squeeze riveter was built in the summer of 2010. A few weeks later, it was run as a fully-functional demo at the SAE Aerospace Manufacturing and Automated Fastening (AMAF) conference in Wichita, where it proved to be a popular exhibit. In 2011, Electroimpact engineer Reese Allen wrote and delivered a paper about the coaxial process at the SAE AeroTech conference in Toulouse, France, which can be found through the “Documentation” link on this page.

The coaxial process is conducted along a horizontal working axis, with the work piece held in a predominantly vertical orientation and the heads mounted to a supporting U-frame structure. On a traditional C-frame riveter, the riveting heads (especially the upper head) are mounted quite high relative to the factory floor, making them very difficult to access for operators and maintenance technicians. With the horizontal-axis coaxial riveter mounted to a U-frame rather than a C-frame, riveting occurs at eye-level and no man-lifts or ladders are needed for access. This simplifies maintenance and allows for fast manual tool changes. Additionally, chips produced during drilling tend to fall away from the tool point, rather than lingering on the panel where there is potential for damage if the machine clamps up on them.

Part positioning is accomplished using a CNC positioner which shares the same control as the riveting heads. We primarily offer this system with a Siemens control and a Kuka robot for part positioning. With a robotic positioner, we make use of Electroimpact’s proprietary Accurate Robot technology, which dramatically enhances the positioning accuracy of industrial robots to within aerospace manufacturing tolerances without the need for external metrology, such as laser trackers. (For some specific applications, a custom CNC positioning system may be proposed in lieu of a robot-based system, such as for parts with strictly flat or cylindrical geometry.) We also offer this system with Fanuc control and robots. In all configurations, we employ a set of Baumer laser distance sensors to ensure normality of the part surface to the drill axis.

The coaxial head design is ideal for fastening frames, shear ties, and stringers to fuselage skins. It can be applied to most applications in which the skin has little or no concave curvature, and where there are few or no parts protruding from the skin surface. Applications for which this style of riveter is very well-suited include:

Electroimpact is also currently developing other styles of squeeze riveting machine for other applications, such as large fuselage panels and wing panels. For more information regarding the latest in Electroimpact squeeze riveting technology, please contact Peter Zieve (peterz@electroimpact.com).