More than 30 Issueing Authorities worldwide currently have polymer notes in circulation and more than 10 Issueing Authorities have a Composite substrate technology in circulation. Recent developments are indicating that Central Banks are increasingly working with a mixed banknote substrate strategy. When evaluating the life cycle of a banknote, a mixed or pure polymer based substrate strategy for banknotes requires a special focus when the banknote needs to be shredded. Due to static charge polymer based substrates tends to get stuck in various places within the destruction system. Hunkeler Systeme – a leading polymer shredding specialists with a high installed shredding equipment base at various Central Banks – developed special solutions avoiding that banknotes stucking during the destruction process (see flow chart
below 1 – 3).
Additionally, Hunkeler Systeme is using for the complete shredding proces special hard steeled and coated knives which guarantee a very long life time compared to what is being used in general. A special focus should be put to the integrated polymer granulator customized by Hunkeler (indexable inserts instead of single-piece cutting blades) which guarantees a smooth granulate process (see flow chart below no. 2.) Most important factor in the granulating process is the heat development. The special designed second shredding station is based on traditional polymer destruction and will not generate any heat melting the polymer. The granulator is in addition fully controlled via temperature sensors to reach a 100% system control.
Briquetting is not possible for pure polymer based banknotes or composite notes with a plastic share above >25%, but Hunkeler Systeme developed customized screw / rotor sluice discharge for the bagging of the polymer particles out of the granulator. A press container can also be adapted to the end section for higher volume destruction solutions (see flow chart below no.4).
It is highly recommendable that an extraction unit with a material silo and a discharge device is being added to the system. This extraction unit is well suited for the extraction of polymer banknote dust and pourable material. The antistatic filter elements are automatically cleaned during operation by compressed air, the filtered air flows back into the production room.
The software which is steering the destruction process is being developed by Hunkeler’s In-house IT experts and can be updated remotely from the headquarter in Switzerland at any time needed. The workfow management software continuously monitors the entire disposal process. The software continuously compares the feed quantities against the output quantity of shredded materials. Every step of the process is recorded in a job report and can be traced back to the start. The data is stored and displayed in a central control station and the graphical interface provides the supervisor with both live data and historical data.
This holistic set up by Hunkeler makes destruction of polymer notes easy to monitor in a secure production environment.
A Video animation can be seen here..