Pick-to-Light for Bumper Assembly

At its factory in Zwickau, automobile supplier SAS Automotive Systems optimizes the production of cockpit modules with a pick-to-light system

SAS Automotive Systems produces cockpits for the automobile industry, individually mounted and just-in-time. For the assembler at SAS in Zwickau, Germany, that means, that one module has to be finalized every minute. To improve this work, a pick-to-light system now indicates exactly what component has to be installed in which order. Turcks pick-to-light solution could convince the SAS specialist because of the comprehensive approach consisting of sensors, I/O system and fieldbus gateway, as well as its easy integration into the production line.
  • Pick-to-light systems optimize manual production processes and reduce the error rate remarkably

  • The light signal marks the box with the component that is next to install

  • A diffuse mode sensor integrated into the signal light acknowledges the removal automatically

  • Turcks modular I/O system BL20 guarantees a reliable communication to the plant controls via Modbus

  • Oliver Graf, SAS Automotive Systems

At the SAS location in Zwickau they were looking for new ways to reduce sources of error during the production and composition of the cockpits. SAS Zwickau produces cockpits for the Volkswagen vehicle plant next door. Oliver Graf, jointly responsible for the plant design, describes: “About 2.5 hours before delivery time we get the demand requirements and then have to produce and deliver the cockpits in the allotted time.“ To be able to produce a number of up to 1,300 cockpits a day, one cockpit has to be completed every minute.

If quality control discovers an error at the end of the production chain, it has to be corrected manually. Therefore, the easiest way for flawless production is an integrated quality control during the installation process. Before the pick-to-light system was introduced, the assemblers read the respective configuration of the cockpit from an order slip and equipped the cockpit accordingly. Mistakes couldn’t be completely avoided.

Less mistakes with pick-to-light
With the pick-to-light system from Turck and Banner, SAS could reduce the mistakes during cockpit mounting remarkably. The system translates the configuration of a cockpit into light signals, which show the assembler the needed components in the right order. All output trays were equipped with a signal light and the assembler simply takes a component from the illuminated tray and installs it into the cockpit. The signal light has an integrated light sensor that acknowledges the removal of a component automatically. The system monitors the progress and sends the information to the product line controls; this captures the order completion and releases the light signal for the next order.

An unwanted activation of the light sensor is impossible because of the background suppression set at 100 mm. In addition, the system provides another protection level so if the assembler picks something from the wrong tray, a red light signal indicates the mistake immediately.

Competitive advantage: system approach
SAS decided to use the solution from Turck for various reasons. One of the main requirements was the automated acknowledgment through a light barrier or alternative sensors. Turck was not the only provider that offered this solution, but what convinced the customer in the end was the fact that the automation specialist from Mülheim offered a solution and also provided the needed hardware for the connection to the production line.

During normal operation, 20 mounting stations got equipped with the pick-to-light system and a K50 signal light was implemented into all relevant trays of the mounting stations. A BL20 I/O system, which was connected over a fieldbus gateway to the line control, is responsible for the signal transfer between lights and controls. Only minor adaptations regarding the software were necessary.

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