INLINE MEASUREMENT | PROCESS CONTROL


able control and processing of raw materials. Accordingly, the requirements for the purity of these materials are particularly high. We see a strong demand for high purity materials by compounders, as well as all plastics manufacturers and processors worldwide,” says Ralf Kulenkampff, Head of Sales, Plastics. “Our customers appreciate the highest detec-


tion rates, process stability, reliability and simple handling offered by our system. This applies to all customers, from cable manufacturers and raw material producers to contract sorters and com- pounders. We have a strong R&D department that is continuously working on new solutions. Through close cooperation with the customer, successful solutions have already been developed and incorporated as standard into the device,” he says. Due to the modular system design of Sikora’s


Purity Scanner Advanced pellet inspection system, different camera types can be used depending on the particular material being inspected. In addition to optical cameras, which reliably detect black specks and discolouration, an X-ray camera can be installed to detect metallic contaminants. Many systems on the market use a maximum of two optical cameras, the company claims. However, these can quickly reach their limits due to relatively low coverage and field of view. For this reason, Sikora offers the option of a third optical camera. This offers a significantly higher detection rate and is particularly advantageous where a Purity Scanner Advanced system is integrated directly into a production line, as inline multiple sorting with a typical two-camera system is not possible. Sikora says that the Purity Scanner Advanced system automatically separates out detected


Below: Sikora’s Purity Scanner Advanced pellet inspection system is designed for 100% inline inspection


IMAGE: SIKORA


Above: Cedric Steeg, one of the RCS quality assurance team, holds a material sample in front of Sikora’s Purity Concept V


Checking rPET pellets in a recycler’s lab


For plastics recycling companies, lab-based quality control is vital for checking products for contamination. Sikora illustrates this in a customer case study. RCS Group, a family-run, medium-sized recycling and waste management company based in Werne, Germany, uses Sikora’s Purity Concept V for the quality control of rPET flakes and pellets. Due to the potential for impurities to remain in its rPET production, RCS uses the Sikora inspection and analysis system in its lab to check the rPET pellet quality before further processing into preforms. A material sample containing 80g of rPET pellets is placed on the sample tray of the testing device, says Sikora. Within 30 s, the tray is automatically moved to the inspection area, scanned with the integrated camera and analysed. A projector marks contami- nated pellets in colour directly on the sample tray. Simultaneously, the affected material is displayed on the monitor with an indication of the size of the contamination. This facilitates the assignment and removal of contaminated grains for further analysis. “With the Purity Concept V, we can find contaminants in just a few seconds. This previously required up to 45 minutes of manual sorting,” says Pascal Renner, Head of Quality Management at RCS. “Not only do we save time, but we also get clear, reproducible results. With the system, we detect black spots as small as 50 µm; the human eye can’t keep up here.” RCS Group has defined quality control limits that the recycled


material produced must not exceed. Sample analysis allows the recycler to determine whether or not a batch meets the required criteria. The test results are documented and stored for traceability for five years.


In addition to black spots, RCS also checks the material for


butterfly grains. By evaluating the material with the Purity Concept V, Sikora says conclusions can be drawn about any mechanical problems that may have occurred during granulation that lead to deformation. Additionally, the system can also be used to analyse amorphous and crystalline pellets as well as test plates.


www.plasticsrecyclingworld.com November/December 2023 | PLASTICS RECYCLING WORLD 31


IMAGE: SIKORA


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