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| The high-resolution camera from the FQA detects defects in the material |
Plastic films are of great importance for everyday, domestic and technical use and are indispensable in their application as packaging materials as well as from their diverse use in agriculture, the construction industry, medical technology or the electronics industry. When developing and processing films, it is always necessary to find a compromise between low manufacturing costs and demanding technical requirements. This challenge will become even more complex in the future due to the increasing use of recycled and bio-based materials and the associated increase in batch fluctuations. Optical film inspection is an established method for evaluating material- and process-specific influences on the quality of extruded films.
Optical detection of impurities and defects
As a producer of extrusion machines on a laboratory and pilot plant scale, which are used in the development and production of plastic films, Brabender now also offers its customers a newly developed film quality analysis system – the Brabender FQA. The system enables the detection of inclusions, inhomogeneities and defects as well as their automatic classification according to defect classes and defect types: “The heart of the FQA is a high-resolution camera that detects defects such as black specs, gels, fish eyes as well as extrusion lines and streaks”, says Michael Stanko, Business Development Manager Plastics & Rubber at Brabender. With the help of the recorded size distribution and number of defects, the film quality index FQI is continuously determined, which can be used as a reference value for incoming goods inspection and quality monitoring.
Wide range of applications in the laboratory and production field
The FQA unit can also be adapted to peripheral devices such as the Univex flat film take-off, the blown film take-off and the Brabender Auto Grader and can thus be used to evaluate the optical properties of both flat films and blown films. The connection of the extrusion process data with the determined optical properties within the self-developed MetaBridge software and the resulting possibility of building up a holistic process understanding should be emphasised.
In addition to the characterisation of optical film properties as part of material development at laboratory level, the Brabender FQA is suitable for inline process monitoring in the production process.
Quality assessment in recyclate processing
Currently, the processing of recyclates in particular, as a consequence of the need for a more sustainable use of raw materials and resources, presents plastics processing companies with major challenges in terms of the contamination that these secondary raw materials carry with them. “Especially in plastics processing with increased use of recyclates, we continue to see the potential of optical film inspection as an important tool for evaluating the processability and application-specific suitability of plastic formulations”, explains Stanko. This is not only about optical features that influence the visually perceived quality (e.g. transparency) of a product. More important is the evaluation of the influence on the technical properties of a film. Film inspection provides the necessary basis for this with the automatic determination of defect distribution.
