For faster, higher performance appearance inspections and space-efficient applications

NTN Corporation (hereafter, NTN) will begin mass-production of the “i-WRIST*1” wrist joint module for some manufacturers of automotive components and industrial machine parts for appearance inspection applications. The existing “Parallel Link High Speed Angle Control Equipment” has been developed with a wider range of moving angles and a structure that allows high-speed positioning in any direction within a hemispherical area, and changed its name into i-WRIST. Mass-production will begin from August 2018.



The “i-WRIST” developed by NTN uses a special link mechanism*2 that allows the associated device to be more compact and space-efficient, and move over a wider range of movement. This enables minor changes in positions (angles), which perpendicular multijoint robots and pan-tilt structures*3 perform poorly with, to be made at high-speed like human wrist. The maximum operating angle of the conventional “i-WRIST” was 45°, however the operating range has been expanded to 90°, which allows appearance inspections of complex shapes or hemispheric surfaces conducted by humans to be replaced with “i-WRIST.” Appearance inspections of 60 areas can be achieved in just 8 seconds, depending on the shape and size of the workpiece and the speed of the image processing system.



NTN is aiming to offer “i-WRIST” for appearance inspection applications by combining it with an XYZ stage mechanism. Mounting a camera and lighting device to the mechanism will enable objects to be inspected with camera photography from the side. The addition of an Rz axis to rotate the workpiece has allowed a shorter XY stage stroke to be used for a more compact overall unit size. The camera and cables have been routed inside the link mechanism to prevent them becoming kinked after repeated swing operations. The proprietary controller and console developed by NTN means teaching operations can be conducted easily, without the operator requiring any complex numerical calculations.



After announcing the developed product in 2012*4, NTN has made numerous improvements*5 to meet the needs of various applications that were identified during technical proposals for grease application and cleaning (such as air blowers). The product's automated high-speed, high-performance appearance inspections and its space-efficient size have been widely recognized, and NTN will begin mass-production for appearance inspection applications. As the working population continues to decline in Japan, the demand for automation is expected to grow for appearance inspections that had relied on manual work. NTN is focusing on automation and labor-saving technologies for such worksites, and continue developing products that further increase productivity and quality as a way of contributing to society.