The six levels of a serialisation system

Ask what a serialisation system is and you will usually get an answer about equipment: a print-and-apply head, a camera, a checkweigher, a case packer. That is one level out of six.

The layered model below is the one most serialisation suppliers and projects use, in one numbering or another. It borrows the ISA-95 automation hierarchy and lays the serial-number world on top. Learn it by heart: almost every serialisation problem can be placed on it, and the level where a problem lives decides who has to fix it.

Level 0: the pack

The physical object. A folding carton, a bundle, a case, a pallet. No electronics, no data, but every constraint above starts here. Substrate, print surface, carton finish and the space available for the code determine what the levels above can actually achieve. A glossy varnish decided by marketing is a Level 0 choice that shows up as a Level 1 read failure.

Level 1: the devices

Printer or labeller, code reader, vision camera, checkweigher, reject unit, light curtains. Each one does a single job and reports a single verdict. This is the level engineers are most comfortable with, and the one that gets the most attention in a specification.

Level 2: the line

The line manager. It holds the serial numbers allocated to the current batch, distributes them to the printers, collects the vision verdicts, decides what is rejected, and builds the parent-child relationships as packs become bundles and bundles become cases. It is the first level where the word data means more than a sensor value.

A line manager has to survive things the devices never see: a short stop mid-bundle, an operator removing a pack from a conveyor, a case opened for a quality sample. Whether it handles those gracefully is most of what separates a good system from a painful one.

Level 3: the site

The site system. It owns the batch across all the lines, handles warehouse-level aggregation, manages palletisation, and produces what actually ships. It is where a batch is reconciled and closed, and where a repack or a late aggregation change has to be recorded.

Level 4: the enterprise

ERP and the serial number repository. Where numbers are generated or requested, where the master data lives, where commissioning and shipping events are recorded for the company as a whole.

Level 5: outside

The external world: regulatory repositories, the European hub, trading partners, contract manufacturers, 3PLs, wholesalers. In the EU, Delegated Regulation (EU) 2016/161 requires the manufacturer to upload each pack’s unique identifier to the repositories system before the batch is released for sale or distribution (Article 33). Data leaves the company here, and once it has left, correcting it is a regulatory conversation rather than a database update.

Where projects actually fail

Not at Level 1. Cameras and printers are mature, and vendors qualify them thoroughly.

The failures cluster at the boundary between Level 3 and Level 4, for reasons of organisation more than technology. Levels 0 to 3 are bought and owned by engineering and packaging. Levels 4 and 5 are owned by IT and by the regulatory or supply chain function. The interface between them sits in the gap between two budgets and two vocabularies.

Concretely, this is what falls into that gap:

• Who decides the line stops. If the site system cannot reach the repository, does the line refuse to start, run on a pre-allocated pool of numbers, or buffer and forward? This is a business continuity decision with a regulatory dimension, and it is routinely discovered during commissioning rather than decided during design.
• The size of the number pool. Too small and the line halts on a network hiccup. Too large and you carry a growing stock of commissioned numbers that were never used, which has to be reconciled and explained.
• Who owns exceptions. A case opened after aggregation, a damaged pallet, a rework. Level 3 knows it happened. Level 4 has already reported the original structure. Reconciling the two is a procedure someone has to write, and it is rarely in anyone’s scope.
• Master data. A product code that differs by one digit between the ERP and the line manager will not be caught by any camera. It will be caught by a regulator, or by a wholesaler rejecting a delivery.

Using the model

When something goes wrong, place it on the model before assigning it.

A code that will not read is Level 1, unless the print surface changed, in which case it is Level 0. A bundle with the wrong contents is Level 2. A batch that will not close is Level 3. A number that exists twice is Level 4. A rejected delivery is Level 5.

On most of these projects, a large part of the lost time goes on the wrong team investigating the wrong level. The packaging engineer spends a night shift cleaning camera lenses for a product code mismatch that sits in the ERP.

The model solves nothing on its own. It shortens the conversation, and it makes the gap between Level 3 and Level 4 visible early, while it is still cheap to close.

References

• Commission Delegated Regulation (EU) 2016/161 on the safety features on the packaging of medicinal products for human use, Article 33: eur-lex.europa.eu