Radio Frequency Identification (RFID) technology is a contactless automatic identification technology that emerged in the 1990s. It utilizes the transmission characteristics of radio frequency signals through spatial coupling or radar reflection to achieve automatic identification of target objects. Compared to traditional magnetic cards and IC cards, its greatest advantage lies in long-range and contactless identification. This eliminates the need for manual intervention during identification, making it suitable for system automation. It is also resistant to damage, capable of identifying high-speed moving objects, and offers quick and convenient operation. Focusing on the application of RFID technology in the tire industry, this paper primarily investigates the RFID implant process and reliability testing after tag embedding in tires.
1. Implantation Methods
Efficient implantation methods are essential for the industrial application of RFID tags in tires. Implantation primarily occurs during the tire molding process and on the surface of the green tire. The following provides a brief overview of the specific implantation processes.
1.1 Embedding During Tire Curing
RFID tags can be embedded into tires during the curing process, specifically during the production of the tire green body. The method involves adhering the electronic tag to a semi-finished tire component using adhesive film. These components may include the belt layer, carcass plies, sidewall compound, or liner. The adhesive film must be compatible with the material of the corresponding semi-finished component.
On the molding drum, after the tire carcass plies are applied, the electronic tag is affixed to the ply surface using adhesive film. Following the carcass wrapping process, the electronic tag is encapsulated within the sidewall. The embedding method is essentially identical for both all-steel and semi-steel tires.
1.2 Surface Embedding in Green Tires
In addition to embedding electronic tags during tire molding, tags can also be embedded into green tires after molding is complete. This method involves affixing the electronic tag to the green tire’s outer surface using adhesive film. When bonding to the liner surface, liner adhesive film must be used; when bonding to the outer sidewall surface, sidewall adhesive must be used. Compared to in-molding, this method reduces the tag’s read distance. This occurs because during vulcanization, the rubber near the mold exhibits greater fluidity than the internal rubber. Consequently, the electronic tag experiences relatively higher stress, impairing signal transmission.
2. Implantation Location
Tires are composed of multiple semi-finished components. The implantation location of the electronic tag within the tire is critical for reading and writing chip information after tire assembly. The chosen location must ensure tag reliability while minimizing impact on tire quality. Therefore, selecting the implantation site is a key consideration for applying RFID electronic tags in tire quality control processes.
Embedding the tag between the filler compound and the sidewall rubber meets performance requirements. This method is completed during the carcass bonding process: after the carcass plies are sewn and pressed together, the electronic tag is affixed at the position marked by laser positioning markers, followed by subsequent manufacturing steps.
Bluetooth RFID Reader
3.Reliability Testing of Electronic Tag Encapsulation
Tires with implanted RFID electronic tags undergo bubble detection, X-ray inspection, dynamic balance uniformity testing, and durability testing to verify the tags’ resistance to bending, interference, and high temperatures, as well as their potential impact on tire performance.
3.1 Air Bubble Detection
Typically, foreign objects trapped within tires may separate from the rubber after prolonged use, causing gaps to widen and ultimately leading to tire failure. We conducted air bubble inspections on both mass-produced RFID tires and those tested on the road. Results showed no air bubbles formed at the RFID tag implantation sites. Therefore, RFID tags integrate well with tires without causing internal bubbles.
3.2 X-ray Inspection
Tire X-ray inspection equipment allows structural examination of implanted RFID tags. Given that tire manufacturing involves high-temperature and high-pressure processes, RFID tags may sustain damage during this stage, potentially impairing their communication capability. X-ray inspection clearly reveals the RFID tag’s position within the tire. Test results indicate that for newly produced RFID tires, tags in the mid-sidewall area exhibit longer read distances due to the thinner material and reduced RF signal interference in this region. Tags near the bead area and shoulder regions demonstrate shorter read distances. For tires that have completed road testing, RFID tags in the mid-sidewall and shoulder areas may become unreadable, while those near the bead remain readable. Dissection of road-tested tires reveals poor soldering between the RFID tag’s antenna and chip. This occurs because significant bending deformation in the mid-sidewall damages the tag’s antenna structure, impairing signal transmission.
3.3 Dynamic Balance Uniformity Testing
Parameters like dynamic balance uniformity directly impact tire stability and safety during operation. Using dynamic balance uniformity testing equipment, we examined tires implanted with RFID tags. Results confirmed the RFID tags’ actual mass is only 0.02g, meaning their implantation does not affect tire dynamic balance uniformity.
3.4 Durability Testing and Road Trials
To ensure experimental safety, indoor mileage testing must precede actual road trials of RFID test tires. Conventional durability test results confirm that the embedded RFID tags do not affect tire performance during operation. Only after passing indoor tire durability tests can road trials proceed. Road test results confirm that under various real-world road conditions, the RFID electronic tag does not affect tire quality. Furthermore, data stored on the chip remains readable even after tire end-of-life, enabling full lifecycle tracking and management of the tire.
4.Conclusions
Through testing, the optimal implant location and method for electronic tags were validated. Research focused on reliability testing of the electronic tags, primarily conducted via bubble inspection, X-ray examination, dynamic balance uniformity testing, durability testing, and road testing of the test tires. The test results confirm that implanting RFID tags within tires does not compromise tire quality or safety performance.