SUMMARYThree-dimensional forming is a key technology for the application of sustainable materials, like paperboard, in packaging technology. Until now, deep drawing is not considered as a suitable process for manufacturing of packaging components with advanced geometrical design because of the sensitive process and a large number of failure mechanisms. To better understand and apply the physics of deep drawing, the process was studied by experimental investigations. Therefore, an evaluation strategy for formed parts was developed to describe their quality by measurable values. The influence of the technological parameters temperature configuration, moisture content of material and blank holder force on the quality of formed parts was described by a statistic regression model. This model gives an indication of the quantity and the direction of effects that parameter changes have on the quality of 3D-formed parts. An optimization of the process according to quality criteria showed that, in a first step, the quality of cylindrically drawn paperboard parts was increased drastically compared with that of the state of the art. Furthermore, the existing limits in the height of formed parts were exceeded, and the geometrical shape of the base offered far more opportunities for packaging design than expected. The process turned out to be suitable for a flexible manufacturing of packaging components for multipart packages from paperboard, which are highly sustainable in terms of recycling and reuse of fibres and thereby able to compete in the marketing-oriented packaging sector.

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Paper and paperboard are widely used in various types of packaging. Paper-based packaging is a recyclable, biodegradable, renewable and sustainable product, which gives it certain advantages over most plastic-based packaging materials. Although paper-based packaging, in some areas, lacks attractiveness in terms of visual appearance, 3D forming is an important method for producing advanced shapes from paper and paperboard, suitable, for instance, for modified atmosphere packaging. That said, very little is known about the deformations experienced by paper-based materials in 3D forming. Understanding the role played by the mechanical properties of paper and paperboard in the 3D forming process is key to improving performance. This paper presents experimental results obtained using three different forming devices designed to be used with paper-based materials and links the formability data with specific mechanical properties of the paperboard samples. Paperboard properties that were found to correlate with formability were as follows: compressive strength and strain, tensile strain, paper-to-metal friction and out-of-plane stiffness. The requirements for formability are different for the fixed blank forming process and sliding blank forming process.

Heat sealing behavior of mono-polyolefins and paper-based materials is drastically different from conventional multilayer plastic laminates. This paper presents the effect of sealing conditions on Hot-Tack and Cold-Tack for an oriented polypropylene (OPP)-based polyolefin laminate with either polyethylene (PE) or cast polypropylene (CPP) sealing layer and two different barrier paper materials carrying a thin acrylic copolymer sealing layer. The investigations include pressure, temperature, time, jaw pattern, and climate conditions (moisture). It is shown that the monopolyolefins reach comparable Hot-Tack and Cold-Tack ranges compared with the reference polyethylene terephthalate (PET)-aluminum (Al)-PE laminate. The CPP laminate exhibits a narrow sealing window near the range in which shrinkage is observed. While for the polyolefins temperature plays the main role, the sealing of paper materials turned out to be dependent on pressure, time, and moisture content in paper. Due to a rupture through the polymer thin coating, the Cold-Tack is dominated by a delamination of paper and coating. Consequently, the Cold-Tack is drastically lower than with PETAl -PE laminate. Monopolypropylene films exhibit extremely narrow sealing window, which shall be taken into the design consideration of bag formfill-seal (FFS) machines. Polymer coated paper can be potentially used at high-speed FFS; however, special attention shall be paid to moisture content control and filling.

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Optimization of the quality of deep-drawn cups requires methods for precise measuring of quality criteria. This paper presents new objective methods to describe the quality of deep-drawn packaging components made of paperboard. The state of the art for quality analysis in three-dimensional paperboard forming is presented. Methods for the analysis of visual quality using image analysis and for the analysis of shape accuracy using surface scans are developed. Experimental results are used for the verification of the methods and for the investigation of influences of main process parameters. The new methods are found to be both precise and objective. A large blankholder force has been shown to cause an increasing number of wrinkles and has a negative influence on the shape accuracy. A high die temperature also increases the number of wrinkles but enhances the shape accuracy. The punch temperature has no effect on the number of wrinkles, but high punch temperature has a significant and positive effect on the shape accuracy.

The visual and mechanical quality of paperboard packaging components formed by deep drawing closely corresponds to the wrinkle distribution within the material wall section. Assessing this quality of paperboard packaging components currently relies on very slow or even subjective methods. Therefore, counting the number of wrinkles and measuring the mean distance between wrinkles proved to be a sensitive strategy for the evaluation of quality levels in deep drawing formed paperboard containers like cups or trays. A method introduced by Hauptmann proposes the measurement of the distances between 10 wrinkles in machine direction and 10 wrinkles in cross direction for each sample. However, this method is unsatisfactory because it can only observe a small part of each sample and is subject to deviation through the individual judgement of the person carrying out the survey. Further methods, as well as their respective application range, are listed in Table . Hence, it is desirable to automate the wrinkle survey to be carried out without operator influences to the measurement. This paper introduces such an automated measuring method. The given method relies on recording the sample surface topography through laser‐distance measurement. An evaluation algorithm, which enables the detection of wrinkles in the topographic data, is proposed. Furthermore, it is shown that the method yields feasible results and is capable of generating reliable quality information in considerably reduced time frames.