CETIE, whose members include Emhart, O-I, Tiama and Verallia, discuss a single, universal method which can trace each individual glass container.

In the food industry, traceability is absolutely essential, not only for foodstuffs but also for other components which come into contact with the food: the primary packaging.

For the best possible traceability, we need to be able to identify the object that we want to trace, at any point in the value chain (when the packaging is produced, when it is filled, at the various storage and distribution points, and especially when it reaches the end consumer). This individual identification system means we can retrieve key information regarding the object: the supplier, the exact time and place of production, which can help us work out the exact conditions in which it was manufactured (settings used in the process, material used, personnel involved) and potentially analyse anomalies detected at any point in the value chain.

What may seem like a simple prospect becomes more complicated when glass containers, bottles and jars are involved. There are several obstacles that hinder tracing these receptacles:

  • Once a glass manufacturer has blow-moulded and shaped the bottles, they undergo a series of stages, theoretically in the order in which they were produced, but this is not necessarily the case. So when they are stacked on a pallet holding one to two thousand bottles, the pallet is identified but it may contain bottles produced at slightly different times, and not necessarily consecutively. It is the pallet itself which carries identification markings, and not the bottles. This reduces the amount of objects traced, but prevents tracing of each individual container.
  • As for the bottler, they must conserve the link between the bottle used and the pallet to which it belonged. This creates a connection between incoming and outgoing products, so that we can trace which pallet of empty bottles the finished product came from, if necessary. This is so as long as the bottling line precisely records the first and last bottles on the pallet, which is rarely the case.
  • As it is indexed to the production machine, it can tell which section of the machine each bottle has come from, and can therefore determine which mould was used to make the bottle out of the many moulds in place on the machine at any one time, in general from 12 to 36. This information is crucial for tracing glassware.
  • Its software is able to modify the code for each bottle, so that it engraves a unique code on every bottle.

These limitations and relative imprecision, could be overcome if each bottle could be individually identified as soon as it was moulded.

At any stage of the process, and without having to follow up complicated links and connections, we would know that a particular bottle was no. X, produced at time T (right down to the second), produced by which glass manufacturer and at which location (plant, production line).

Towards a code for each container

For several years, some suppliers of machines designed for the glass industry have been developing lasers which can mark the bottles “hot of the press”, meaning as soon as they are shaped and while their temperature is still close to 400°C.

As the bottle passes in front of the laser, it sends precise pulses to a designated location on the glass, melting the surface to create dots with a diameter of less than half a millimetre.

The distribution of these dots creates a binary code (0 = melted dot / 1 = flat dot) in the shape of a square of dots or a matrix, known as a data matrix. It is a bit like the QR codes that you scan with your phone.

Asides from the ability to trigger the laser at the exact moment when the bottle passes in front of it (as the bottles go past at a fast but not totally regular pace), this device offers several other advantages:

This code appears discretely on the bottle as it is a 6-to-7 mm wide square, made up of domed and flat dots which are naturally all the same colour as the glass.

Machines with built‑in scanners can read the code, for instance an automatic inspection station at the end of a glassware production line, or a device at the beginning of a bottle filling line. It can also be read, however, using a smartphone for a spot check in the production/distribution chain, or even by the end consumer.

Developing laser marking has been a complex process, due to the need to ensure optimal efficiency and reliability for continuous production lines under difficult conditions.

Glass manufacturers will not be able to equip all their production lines with laser marking, as in some cases space constraints prevent the investment being possible, and the cost of the equipment also currently limits their wide-spread use.

Individual codes for hundreds of billions of items of packaging?

To guarantee totally individual codes, we need to collectively find the “best” system, and also agree on the same international standard. To avoid ending up with the same “number” on two bottles made by two different glass manufacturers, all glass manufacturers should ideally use the same system, or at least use coordinated and compatible systems.

Cetie has therefore brought together the major inter-professional players in its ad-hoc “Hot‑End Laser Coding” working group. These include the main international glass manufacturing groups, manufacturers of inspection and control systems, and brand owners with an interest in this area.

The group members first agreed on the number of dots which the matrix should contain: 14 x 14. In binary code, this matrix is equivalent to a 16-digit number.

This relatively small matrix is the largest matrix that can be engraved on articles produced at high speed, typically 25 and 33 cl beer bottles. Manufacturers are therefore coordinating their processes for the most demanding products in terms of speed (more than ten products to engrave per second).

Among the various coding systems already tested, one offers the benefits of being compatible with the 14 x 14 matrix and including the production date (down to the nearest second), the mould number, and the production location on the bottle.

As it is impossible to produce two bottles on the same machine using the same mould in the same second, this system generates a different number for each of the tens of billions of bottles produced worldwide each year.

Cetie to assign a number to each glass-manufacturing production line in the world

The system's only limitation: creating a 4-digit code for each of the 3000 production lines in the world. The group members have suggested that Cetie simply assign production line numbers to all glass manufacturers who want to set up laser marking.

The marking system, which offers many other possibilities beyond traceability, is described in the document "DT40.00", currently being finalised at Cetie. In particular, it outlines the system for recording production line numbers.

All glass manufacturers wishing to set up laser marking should contact Cetie to receive the amount of numbers corresponding to the quantity of lines that they wish to equip with the system. Registering these numbers will be free, and available to anyone registered with Cetie (also free of charge).

It will of course be flexible if a glass manufacturer decides to equip more lines with the system, and regularly updated to take into account plant sales and changes in name. Over the course of 2020, Cetie will offer each glass manufacturer the chance to sign up, using a specific procedure to centrally record the information, and providing an ideal way to trace glass containers!

Scope of the Cetie group: Laser coding on glass packaging

Working Group chairman: Olivier Dangmann, Innovation Manager - O-I Manufacturing, France

This group develops a harmonised approach to coding of production data of glass packaging by laser marking for traceability applications within the glass plant and by downstream customers.

Companies participating in the Laser coding group:

AB-InBev (Belgium)

Ardagh (Germany)

BA Glass (Portugal)

Bucher Emhart Glass (Switzerland)

BV Glas (Germany)

Encirc (UK)

Gerresheimer Essen (Germany)

Heye International (Germany)

Konatic (France)

Moet & Chandon (France)

O-I Manufacturing (France)

Saverglass (France)

Stoelzle Masnieres Parfumerie (France)

Tiama (France)

Verallia (France)

Verallia (Germany)

Wiegand Glas (Germany)

*Josquin Peycere, Secretary General, Cetie, Paris, France


Photo credits, Bucher Emhart Glass and Tiama