Flexible manufacturing systems are widely established across the motor industry, but installed equipment may not be easily adapted to new or updated models.
At the Nissan plant at Sunderland in the U.K., a new mechanical centralizer was needed for automated glass installation on the latest Micra and Note models. The centralizer locates at six points around the edge of the glass and consistently to a known position in preparation for the next stage of the production process.
A new system was necessary both to provide accurate information for the two vehicles and to adapt easily to future products. Capley Marker was chosen to supply the system; the company previously had installed five cameras at Nissan and converted a separate line to Cognex In-Sight cameras.
The key project requirement was to determine the glass type on the line, which could be one of four variants: Micra fixed side window right-hand side (RHS) and left-hand side (LHS); and Note fixed side window RHS and LHS. A similar system is used on a second line, which produces the Qashqai.
Two In-Sight 5100 cameras are installed, with one positioned in each cell to the side of the assembly line. Each camera is fixed at the required height by a rigid steel stand mounted to the cell base. The In-Sight cameras use Cognex’s PatMax technology, which uses advanced geometric pattern matching to locate parts. Cognex states that even under extreme conditions the tool can significantly reduce or eliminate fixturing requirements and cost. For locating parts or features, PatMax provides the maximum vision inspection yield and reliability available in a vision system, the company says.
Using a Fanuc six-axis robot with RJ-2 control, the cameras provide the robot with two essential pieces of information. First, a digital signal from the camera is sent to the robot confirming the glass variant; then a serial string is sent from the camera to the robot with the coordinates of the glass, so that the robot picks the glass up in the same position each cycle. The exact coordinates measured are x, y, and the angle of the glass on the vision part of the cell (front to back, side to side, and twist).
The robot locates the glass from the data supplied by the vision system, manipulates the glass edge through a fixed nozzle that applies a continuous bead of mastic to the glass edge, and finally transfers the glass to an offload position where the operator picks it up to fit it to the vehicle. The coordinates are located and relayed directly to the line robot to ensure the robot can access the glass.
With its greater flexibility, the system will better support the introduction of new products at Sunderland and is expected to provide a significant reduction in changeover time, according to Cognex.
Capley Marker is a Partner System Integrator with Cognex, having particular expertise in sensing solutions, motion control, automation, and integration. Cognex designs, develops, and produces machine-based vision systems and computers. The Modular Vision Systems Division of Cognex is based in Natick, MA, and specializes in machine-based vision systems used in the automated production and quality assurance of individual parts.