May 19, 2004While RFID has long played a part in the automobile production line, it has been restricted to expensive and more powerful reusable active tags. Now one company that rebuilds automotive parts is testing whether passive tags can be used in the same harsh environment.
“The automotive parts production line represents an extremely challenging environment for RFID, with a lot of potential radio interference,” says Mike Sheriff, CEO of Airgate Technologies, an RFID technology and services provider based in Allen, Texas. Airgate has been running a pilot using passive RFID tags at a Dallas-based automotive-component remanufacturer.
Currently, the remanufacturer determines in advance the number of components, such as alternators or power-steering pumps, to be rebuilt in a day, and preprint a bar-coded label for each item. That can mean up to 2,500 units and matching labels per day. A bar-coded label cannot be used to identify products prior to painting, as the process would ruin the readability of the label. However, it is up to production line operators to identify the painted units by sight and then attach the appropriate label to the component. It is a process that leads to a significant number of errors that are uncovered much further down the supply chain when customers realize that the items inside the boxes are not the ones they had thought they had purchased.
Because the painting process does not affect an RFID tag’s ability to function, however, a tag can be attached to the component before the component is painted. The component remanufacturer believes that RFID tagging could be used to correctly identify rebuilt items, thereby significantly increasing the level of customer satisfaction, as well as cutting the costs of having items returned.
In the now-completed first part of the pilot, Airgate carried out an offsite simulated test of its proposed RFID implementation followed by an onsite scheduled off-production timed implementation test. The onsite pilot started in mid-April using an RFID reader from Alien Technology and read/write tags operating at 915 MHz. The tags carried an embedded serial number and supported read ranges of up to 6 feet. The reader was deployed on the assembly line at a planned tagging station and a planned component-assembly station to measure potential RF interference and read ranges. According to Airgate, by adjusting the actual antenna of the reader system, it was able to ensure a 100 percent read rate during the trial.
With the first part of the pilot completed, Airgate says it is testing a number of passive tags from various manufacturers for the final deployment and working with its client and vendors to get a better pricing on the tags.
“We have told our client to prepare for 40-cent tags at a minimum,” says Sheriff, who says he expects the actual price to be well below the dollar-plus prices common to active tags. The tags being tested have been around 1 by 2 inches and are attached to the outside of the component using epoxy glue. The size of the items they tag are usually about 10 inches long and 5 inches in diameter and weigh between 20 and 25 pounds. Sheriff says that its client is also trying to determine if there are additional business benefits further down the supply chain with its own customers using the tags to receive and maintain their inventory. If it discovers that the benefits are significant enough, it may decide to use the higher priced active tags instead.
When the RFID system is fully deployed, a tagging station will be set up for parts prior to their painting. A touch screen with graphic symbols representing each type of rebuilt component will guide the operator to simply touch the correct symbol for the part being tagged. That will create an encoded tag that is applied to the item. Fifteen assembly stations located down the line from the painting stations will share up to three RFID readers with an antenna covering each station. At each station, when a tag is read, a printer will produce a bar code and human-readable label. The bar code label will be applied on finished item and sent to packaging for boxing.
There are also plans to add readers to the shipping area to ensure that pallets are loaded with the right parts. Each pallet will hold 100 items of the same type. Reading the tags on the pallets will be a major challenge for the system, says Sheriff. “These are very dense metal components and getting to read each tag on a palette could well be a problem. However, as we know what is each box, we can load the pallets by reading each tag before placement on a pallet,” he says.
So far, the system planned for the shipping area has yet to be tested. Airgate says it is looking at either modifying the conveyor system by adding gates that can route the boxes to the correct pallet based on tag information or by positioning readers and antenna to monitor pallet building and sound an alarm or flash a light if a box is placed on an incorrect pallet.
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