Light guided operator assembly

Despite an increase in the use of robots for assembly work, many applications are simply not suitable for assembly by machine. For many producers, manual assembly is the only practicable solution. However, by introducing automation, improvements in quality and productivity are available. Light Guided Operator assembly systems (Pick-to-light) eliminate picking mistakes in assemblies.

Mitsubishi Electric’s light guided operator assembly solutions are in use with leading automotive OEMs, where they help control quality in manual assembly processes and improve stock handling. Similarly, customers within the semiconductor industry use it to improve product quality management. Among many other areas of interest are life sciences and medical device assembly applications.

The reasons are clear. Human error when picking parts is one of the most significant causes of mistakes in assembly operations. Typical problems include picking the wrong parts with a similar shape or name, picking and assembling parts out of sequence, and sometimes, simply missing a part from a sequence.

Product inspection can prevent shipping faulty goods to customers. However, it does little to prevent introducing defects to the product in the first place. Moreover, for most companies, waste and reworking are expensive. Eliminating mistakes early in a process before adding any real value to the product is essential.

Products are often assembled from a host of different parts which can look superficially alike. By giving operators clear visual indication of which parts to pick and in what sequence, light guided operator assembly reduces errors and improves quality.

Straightforward implementation

Implementing a system is straightforward. To simplify wiring, terminals at the operator’s work station connect via a dedicated cable to the main controller. Terminals are set up with an address writer and using dedicated software they can be directly mapped to the controller. This allows the applications to be easily configured, programmed and maintained.

The wide range of Pick-to-Light solutions is suitable for most applications. For example, photoelectric sensors provide feedback for needing high operator speeds. They monitor the movement of the operator’s hands. Alternatively, pushbutton or lever feedback offer a more cost-effective option.

Terminals with opening/closing doors provide a physical barrier to selecting the wrong part. These are a   very effective method in eliminating mistakes. Other options include a display to identify how many pieces should need picking from a bin. The systems is flexible and adaptable enough to accommodate most tasks.

Control and integration

Central to guided operator are the Mitsubishi Electric PLCs. Their dedicated masters communicating with the network of terminals. Depending on the complexity of the application, simple control comes from F-series PLCs. More advanced applications can use the L series or Q series PLCs.

Devices such as bar code scanners, electric screwdrivers or vision systems further improves the system. By connecting them helps to tune the systems to the exact needs of the operator. Further enhancements including adding Mitsubishi Electric GOT Series HMIs to display work instructions. Alternatively, integrating robotic technology into the manufacturing cell is possible.

At the same time, the Light Guided Operator Assembly can provide a link between the operator and the higher-level ERP/MES business systems. This allows the sending of new product specifications to manual assembly work places. Furthermore, it allows the tracking of inventory from production for analysis. It also ensures replenishment is managed on an accurate and timely basis.

Finally, the systems address picking errors and helps manufacturers improve quality and productivity.

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