Laser Engraving: A Permanent Solution for Unique Tire Identification

Introduction

In the #tire #industry of today, especially within companies with expansive global sales #markets, the necessity to meticulously monitor and document #product details throughout the complete product #lifecycle has become paramount. Tires are presently identified by a four-digit code signifying the week and year of #production, yet they lack an individualized #identification #code. Consequently, the challenges of effectively marking #information on tires and the issues arising from the absence of transparency in identifying and #tracing tires throughout their #valuechain have underscored the demand for innovative solutions like barcodes, radio frequency identification (#RFID), and #laser engraving. Within laser engraving technology, a distinct mark, encompassing a numerical code, #barcode, #QRcode, or data matrix code (#DMC), is etched onto the tire's surface. This paper delves into this technology, its intricacies, and its application in the tire industry, particularly by the Barez Industrial Group.

Technological Advancements Revolutionize Industry Operations

Across all facets of the industry, technological advancements have streamlined various operations. Understanding a product's status and the capability to #track and #trace different items, particularly after leaving the company and reaching the end #consumer, holds immense significance for production #planning. As a result, numerous industries are actively exploring diverse tools to establish control networks and monitor their product flow. This pursuit of enhanced #control is particularly pronounced in the tire industry, as it is closely monitored and regulated by standard organizations from various nations, who are committed to tracking product trajectories and ensuring lifecycle #transparency. Consequently, tire manufacturers are focusing on marking product information, tracking it from raw material acquisition and production site to final #customer, and tracing potential defects and status issues back to their #source.

Pursuit of Unique Tire Identification

The tire industry consistently grapples with the #challenge of achieving #unique tire identification. As a prevailing #standard, a four-digit code is embossed onto each tire – the initial two digits denote the production week, followed by the subsequent two digits representing the year (Figure 1). This practice inherently prevents the identification of tires produced within the same week. With the emergence of technologies like barcodes and RFID, tire manufacturers have been striving to develop strategies for recording product information on tires. However, each #method carries its own advantages and disadvantages. While barcodes offer ease of use, they only ensure unique identification until the tire is mounted on the rim or used, after which the barcode detaches. Consequently, this approach falls short in ensuring tire lifecycle coverage. In contrast, laser engraving presents a permanent solution accessible to manufacturers, sellers, and consumers alike. By leveraging this method, an array of information can be embedded, including manufacturer details, operational specifics, usage terms, and supplementary particulars.

Laser Engraving Technology: Empowering Tire Marking

The #versatility and #benefits of laser #engraving technology have precipitated its widespread adoption within the tire industry. The tire #sidewall offers ample space for laser-based inscriptions, as demonstrated in Figure 1. Laser engraving's pivotal attributes include:

• Tire Manufacturers: It provides a cost-effective avenue for implementing enduring numbering and registration.
• Tire #Assembly Providers: Ensures assembly accuracy and component conformity.
• Original Equipment Car Tire Plants: Guarantees 100% traceability, offering valuable insights to end customers.
• Fleet Managers: Aids theft prevention, #replacement scheduling, and inventory management.
• Private Customers: Facilitates access to tire history, test reports, and replacement orders.

Furthermore, laser marking's advantages encompass #permanent and tamper-proof engraving for all tire types, encompassing alphanumeric characters and graphics. It also enables complete traceability over extensive periods of tire usage. A comparison of various identification methods is showcased in Table 1.

Key Considerations for Laser Engraving Implementation

It is noteworthy that laser marking leaves a softly grooved imprint on the tire surface that does not compromise tire integrity. This process has already been successfully applied to over 200 million tires and has been proven to be effective. This groove's subtlety is evident in Figure 2, where the engraved groove's depth is negligible compared to the tire's thickness.

As the volume of markings increases, the process cost of laser engraving significantly decreases, with the overall expense only slightly rising. This signifies the substantial portion of the cost associated with automation and infrastructure setup. Moreover, for the numerous existing marking stations globally, the cost of additional marking is minimal – less than €0.01 (US$0.012) per tire.

Importantly, when utilizing laser technology, factors such as heat and residual stresses must be meticulously considered. The type and power of the laser are crucial, with fiber and CO2 lasers being the preferred choices for tire engraving. Notably, most tire manufacturers employ a CO2 laser system with a wavelength of 10.6μm. Engraved elements often include QR codes or data matrix codes, with an optimal size of 12.6 x 34.8mm accommodating up to 60 numeric characters. Optimal engraving depths for passenger tires (PCR) and truck and bus tires (TBR) are cited as 700μm and 900μm, respectively.

Strategic Placement for Optimal Readability

For the best protection of the QR code upon tire mounting, positioning it as close as possible to the rim is advised, as depicted in Figure 3. Furthermore, the QR code's readability is enhanced when its orientation is nearly perpendicular to the tire axis and avoids excessive curvature. Absolute engraving angles should remain under 30° for optimal reading. Additionally, a dedicated clear space devoid of design elements, flashes, venting marks, or color markings, such as balance points, is requisite for the QR code. The tire surface should ideally be uniformly black and smooth.

Laser Engraving Applications at Barez Industrial Group

Addressing the persistent challenge of unique tire identification, Barez Industrial Group is at the forefront of adopting cutting-edge technologies on its production line. Barez aims to comprehensively document information, encompassing raw materials, production dates, batch numbers, tire building machine models, and operator details, and integrate this data within its ERP system. Upon assembly of semi-final products, the amalgamation of their data generates a unique code assigned to each item. This code is then engraved onto the tire and linked to Barez's website and application, offering sellers and consumers access to comprehensive product information. Furthermore, Barez's tire tracking and tracing capabilities endure, even after years of tire usage, supported by meticulous consideration of factors such as engraving quality, time, cost, thermal effects, and residual stress.

Exploring Diverse Approaches

In investigating varied approaches, both fiber and CO2 lasers with a power output of 30W were employed to engrave QR codes onto Barez PCR tire sidewalls. Ensuring optimal readability, these QR codes were meticulously designed and converted into vector form, with adjustments made to achieve suitable engraving imagery. Notably, marking extensive information may necessitate smaller elements and a lengthier engraving process, requiring precision machinery. Further considerations involve managing the darker color of the engraved sections, which can impact software readability. Barez has developed dedicated software within their application to enhance code legibility (Figure 4 and Figure 5).

Navigating Critical Challenges

Post-parameter adjustments and precise tire positioning, a critical challenge in the engraving process, multiple samples were engraved using varying parameter settings. Subsequent examination of the engraved sections elucidated the effects and depth of the profile, with the final engraved QR code's dimensional specifications showcased in Figure 6, aligning with established standards.

Additionally, Figure 7 illustrates two QR codes engraved onto Barez PCR tires, displaying varying degrees of quality. High laser power, while increasing engraving depth, can lead to tire defects, as evident on the right. Conversely, inadequate engraving parameters yield distorted walls and boundaries for the QR code on the left.

Promising Insights for Implementation

To mitigate tire thickness reduction and residual stress during engraving, Barez Industrial Group suggests dedicating a specific region on the tire mold for engraving. This designated area ensures a smooth surface and serves as a guide for operators or machines, aiding customers in locating the engraved region (Figure 8).

(Full paper published in Tire Technology International 2021)