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Pareto-based design of experiments for identifying and comparing optimum sealing parameters of heat sealing applications in packaging machines, TAPPI Journal June 2023
ABSTRACT: Sealing is one of the most important process steps in industrial packaging, because the sealed seam is the most sensitive section of a package in terms of quality. For this reason, a major focus in flexible packaging is the sealing process, and among this, heat sealing is the most frequently used technology. In detail, applications of heat sealing processes are confronted with four conflicting objectives: increasing seam quality, reducing dwell time, reducing sealing temperature, and increasing process robustness towards varying conditions. Typical problems, such as identification of the optimum process parameters or selection of the most appropriate packaging film, are subject to these conflicting objectives.This paper presents a recently published design of experiments for characterizing and comparing heat sealing properties of packaging films based on a multi-objective optimization algorithm. The approach provides easy-to-read charts showing all optimum sealing parameters with regard to the four essential objectives of heat sealing: seam quality, dwell time, sealing temperature, and process robustness. Three case studies show exemplary applications of the new approach: 1) analyzing transport damages of beverage powder packages; 2) identifying and comparing optimum sealing parameter of a standard, mono-material, and fiber based packaging film regarding tightness and visual properties of the produced sachets; and 3) analyzing the effect of additional aluminum layers on sealing characteristics regarding hot-tack.The new design of experiments may provide the basis of a standard test method for the identification of optimal sealing parameters in the heat sealing processes.
Journal articles
Magazine articles
Paper bending stiffness and web tension measurement from a running web using a vacuum and computer imaging, TAPPI Journal May 2023
ABSTRACT: A novel method for measuring the bending stiffness of paper online during manufacturing is introduced. The method uses photometric stereo imaging to detect the shape of the deflection surface caused by a controllable pressure difference over the paper’s surfaces. The hardware for the measurement is based on a combination of two existing sensors, which has accelerated and facilitated the development of the implementation. The deflection and loads are tied together by the governing differential equation for the bending of an orthotropic elastic plate with selected simplifications. An approach to resolve material parameters and in-plane loads without knowledge of traditional boundary conditions is suggested. The presented method was tested in a paper mill during manufacturing. For bending stiffnesses measured online, correlation coefficients 0.88 and 0.92 were obtained compared to state-of-the-art laboratory measurements. However, the results gained from a moving web are noisy and the data requires correction of the slope and an off-set. Although several issues remain to be resolved before the method can be considered as an accurate measurement for industrial use, the theoretical background, the performance of online implementation, and the results are promising. Possible causes for the observed discrepancies and the future development of the method are discussed.
Journal articles
Static Control Methods in Hazardous Areas in Converting Oper
Static Control Methods in Hazardous Areas in Converting Operations, 1994 Polymers, Laminations & Coating Conference Proceedings
Journal articles
Coating Pigment Orientation: A Comparative Analysis of the A
Coating Pigment Orientation: A Comparative Analysis of the Application Mechanisms and Properties of Blade and Roll Coatings, 1995 Coating Conference Proceedings
Journal articles
A laboratory-scale automated vacuum-assisted device for coating of cellulose nanofibrils onto paper, TAPPI Journal November 2025
ABSTRACT: An automated vacuum-assisted coating system was developed to deposit cellulose nanofibril (CNF) layers onto paper substrates, simulating potential industrial geometries while allowing precise control of web speed (10•20 m/min), vacuum time (up to 30 s), and applicator gap (0.5•0.9 mm). Vacuum assistance makes it possible to obtain coat weights over 5 g/m2 in a single pass and increases solids after coating from less than 10% to over 28%• 30%, reducing drying demand by more than 60%. Coat weights were tuned from 6 to over 11 g/m² by varying suspension solids (0.4•0.6 wt%), line speed, and filtration length (20•40 mm), with strong agreement between experimental data and model predictions. Barrier testing showed Kit test values for double folded samples of 9•12 and Gurley air resistances above 4 × 104 s once coat weights exceeded 7 g/m². Comparable performance was achieved with lower fines content CNF (60%) by increasing coat weight, providing technical flexibility and cost advantages for industrial scale-up.
Journal articles
Designing paper and board barrier constructions for food contact applications, TAPPI Journal November 2025
ABSTRACT: This study examines the effect of multiple factors on barrier performance for purpose-built paper and paperboard constructions produced on an industrial pilot coater machine. Impacts from precoat latex chemistry, application method (flooded nip with bevel blade, jet with bevel blade, and pre-metered film coater, laboratory rod drawdown) and precoating calendering were studied in relation to resulting porosity, roughness, and barrier (liquid water, moisture, and oil). Results reveal a complex interaction between controllable and uncontrollable factors, offering insight for designing advanced barrier coatings on cellulosic substrates.
Journal articles
Editorial: Coating innovations for driving the next generation of sustainable packaging, TAPPI Journal November 2025
Welcome to the 2025 Special Coating Issue of TAPPI Journal. As we reflect on developments in 2025, the industry’s focus on sustainable packaging continues to sharpen, bringing several critical coating challenges and opportunities into view.
Journal articles
Influence of base sheet properties on barrier coating performance, TAPPI Journal November 2025
ABSTRACT: Paper packaging offers a sustainable alternative to standard plastic-based materials, particularly for food and beverage applications. With reduced fiber treatment options like fluorochemicals, uncoated base stock often provides little-to-no effective barrier against liquid water, oil/grease, or moisture transmission. Despite the lack of natural barrier performance, base sheet properties can significantly influence the efficiency of applied waterbased barrier coatings. In this study, various base stock properties, such as caliper, porosity, roughness, and ash content, are reported to influence the barrier performance of styrene-acrylic and a copolymer of styrene-butadiene/styrene-acrylate based barrier coatings. These findings will help paper and board producers design better, more cost-effective, purposebuilt substrates for barrier applications in the packaging industry.
Journal articles
A systems approach for process debottlenecking towards a sustainable pulp and paper industry, TAPPI Journal April 2026
ABSTRACT: Increasing the competitiveness of the pulp and paper industry requires an effective optimization of its existing assets in line with a long-term vision for process transformation, production upgrade, and product diversification. Currently, pulp production increase is one of the main sources of additional revenue for the kraft industry. Likewise, energy efficiency is often employed as a cost-effective approach to reduce operating costs, enhancing the possibilities to lower fossil fuel consumption and contributing to a low-carbon economy. On the other hand, reaching higher production targets and facilitating process transformation, such as biorefinery implementation, heavily depend on the status and performance of a mill’s current infrastructure; therefore, a system analysis is needed to assess the new production requirements, the bottlenecks, and the interactions across departments. In order to obtain practical improvement solutions, direct and indirect impacts on process performance and resource utilization should be considered. This work provides an overview of the key challenges that need to be addressed for production increase and energy efficiency improvement. The methodology starts by a scope analysis for debottlenecking and screening capacity limitations vs. mill targets, followed by their ranking (bottleneck ranking diagram). Benchmarking, gap analysis, and root-cause techniques are applied to diagnose system inefficiencies. This mill-wide debottlenecking assessment is then used to guide the selection of a long-term sustainable operation and design a portfolio of improvement projects by avoiding cross effects of the short-term projects on the long term. A case study of a kraft pulp mill is used to illustrate the proposed methodology.
Journal articles
Optimization of optical coverage of board surfaces with assessment of light scattering and absorption using mineral as a coating component, TAPPI Journal June 2026
ABSTRACT: One of the primary functions of mineral inclusion into paper or paperboard is to improve the optical performance of the substrate. A coating may be applied to a sheet in order to cover a dark base, to improve the sheet opacity, to give the correct smoothness and gloss, or to give a suitable surface on which to print. The brightness of a pigment has long been used as a guide for pigment choice in paper and board. However, the measured paper brightness is a function of color and light absorption (K) of the coating and base and the light scattering (S) within the sheet resulting from interfaces with different refractive index. The optical performance can be quantified by measuring the S&K coefficients as described by the Kubelka-Munk model/theory in a filled or coated paper sheet. In coating, this is often assessed as a function of coat weight, and the corresponding physical sheet properties are assessed at the same time; for example, the correct gloss, smoothness, point-to-point uniformity, and printability. The optical performance in the sheet is often not directly related to the pigment brightness, but is largely a function of the particle packing within the sheet and coating layer. In the first and second main sections of this work, respectively, we show how S&K calculations from the Kubelka- Munk equations can be used in coated sheets to determine the optical performance and how this can be used as a predictive tool for the final sheet performance. This is presented for base sheets with different starting brightness. The third section of this work focuses on how mineral combinations in coatings can be used to improve the light scattering and consequently the optical performance of the board. We include theoretical considerations and then finally share a case study for improvement on the optical properties of recycled board.