How RFID Can Error-Proof Appliance Assembly

Today, appliance manufactures are using RFID more frequently for error proofing applications and quality control processes.

Whether the appliance assembly process is automatic or semiautomatic, error-proofing processes using RFID are as important as the overall assembly processes. Now, RFID systems can be used to tell a PLC how well things are moving, and if the products and parts are within spec. This information is provided as an integral part of each step in the manufacturing process.

RFID systems installed throughout the manufacturing process provide a way of tracking not only what has happened, but what has gone right. RFID records where something has gone wrong, and what needs to be done to correct the problem.

Appliance manufacturers often need to assemble different product versions on the same production line. The important features of each part must be identified, tracked and communicated to the control system. This is most effectively done with an RFID system that stores build data on a small RFID tag attached to a build pallet. Before assembly begins, the RFID tag is loaded with the information that will instruct all downstream processes the correct parts that need to be installed.

Each part that goes into the appliance also has a RFID tag attached to it. As the build pallet moves down the assembly conveyor to each station, the tag on the build pallet is read to determine what assembly and error proofing steps are required. Often, this is displayed on an HMI for the operator. If the assembly requires testing, the results of those tests can be loaded into the data carrier for subsequent archiving. The operator scans the tag on each part as it is being installed. That data is then written to the tag on the build pallet. For example, in the washing machine assembly process, the washing machine body sits on the build pallet, and as it moves from station to station, the operators install different components like electronic boards, wiring harnesses, and motors. As each one of these components is installed, its RFID tag is scanned to make sure it is the correct part. If they install the wrong part, the HMI will signal the error.

RFID technology can also be used to reduce errors in the rework process. RFID tags, located on either on the assembly or the pallet, store information on what has been done to the appliance and what needs to be done. When an unacceptable subassembly reaches the rework area, the RFID tag provides details for the operator on what needs to be corrected. At the same time, the tag can signal a controller to configure sensors and tools, such as torque wrenches, to perform the corrective operations.

These are just a few examples of how appliance manufactures are using RFID for error proofing.

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