High Speed Laser Engraving in Anti-Counterfeiting

Counterfeiting is a major and global problem for the pharmaceutical industries, with extremely important societal and economic consequences. It is for instance estimated that 10% of global pharmaceutical sales are conterfeit products, with a much higher ratio in Africa and parts of Asia. In addition to serious health issues, especially in developing countries, the revenue loss for the pharmaceutical industry is estimated at more than $16 billion. Counterfeiting is also a new and relatively safe domain of expansion for organized crime and terrorist organizations.

Laser marking has penetrated a wide range of industries and is today used for traceability and product identification in markets as diverse as automotive, micro-electronics, semiconductor, photovoltaic, medical and packaging industries.

However, the pharmaceutical industry faces specific challenges which have until now limited the use of laser technology for anticounterfeiting purposes:

  • The identification mark should be as close to the primary package as possible, e.g. the syringe vs. the carboard box it comes in, or the vial vs. the palette.
  • The marking process should not alter the product.
  • The mark should be tamper-proof and easy to read.
  • The process speed should be compatible with the production environment.

Alternate technological solutions include inkjet printing and radio-frequency identification (RFID). Inkjet printing is widely used, still is vulnerable to tampering, adds additional consumables and leads to additional production steps. RFID, although well suited for remote checking of a batch, is not compatible with the primary package. Surface engraving by laser is also attractive, but may lead to physical alteration of the container and is also vulnerable to tampering by polishing the code.

Laser internal engraving is therefore today the only technological solution which fulfills all the criteria of the pharmaceutical industry. However, this approach brings serious constraints to the choice of the laser source. The laser intensity at the focus should be sufficient for marking, ruling out continuous wave lasers. The container should be transparent to the laser emission, ruling out UV lasers. Finally, the container integrity should be preserved, which prevents the use of nanosecond infrared lasers. Due to the thermal nature of the laser-matter interaction, micro-cracks are created, which can propagate over time and ultimately lead to glass fracture.

The recent development of industrial-class ultrafast lasers enable internal marking without any damage to the container. Because of the extremely high optical intensity and very short pulse duration delivered by ultrafast lasers, there is no heat dissipation during the interaction process, which means that there is no micro-crack formation. Since the individual spots can be made very small, it is also possible to achieve virtually invisible marking, and yet to guarantee reliable reading under proper lighting.

A first generation of internal engraving systems using diode-pumped Ytterbium ultrafast lasers was developed in 2004 by an industrial consortium, with the support of the European Union. In 2007, a company called TrackInside was formed to exploit the commercial potential of the technology in industrial environments Because of the moderate average power of the laser used, this first generation system was first implemented in the luxury industry, which has the same technical requirements as the pharmaceutical industry, but needs lower production speed.

The development of high power industrial ultrafast fiber lasers enabled the development of a second generation equipment, dedicated to the pharmaceutical industry. While maintaining the quality of the ultrafast laser internal engraving technology, the average power of the laser enables a marking speed compatible with the requirements of pharmaceutical industries. Additional developments were conducted related to the scanning speed, the software control and mechanical handling, to guarantee high quality marking at speeds up to 15 containers per second.

The TrackInside system has a very high accuracy and its flexible engraving process can create a 500 x 500 μm data matrix in less than 40 mm, as well as logos and text, on a field up to 60 x 60 mm. The readability of the marking is rated as grade A-AIM, i.e. the most stringent international regulation.

Ultrafast lasers are today at the nexus of several key technological advances. Strong innovation in the scientific community gives rise to an increasing number of industrial application. At the same time, as the average power of ultrafast lasers increases, more of these applications reaches the level where industrial deployment is economically competitive, further increasing the drive for further laser developments. Let us expect ultrafast lasers to play an ever increasing role in industrial processes, touching on many aspects of our daily life.