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Thorman, S., Rydefalk, C., Hagman, A. & Granlöf, L. (2024). Dynamic out-of-plane compression of paperboard — Influence of impact velocity on the surface. TAPPI Journal, 2024-February, 113-122
Open this publication in new window or tab >>Dynamic out-of-plane compression of paperboard — Influence of impact velocity on the surface
2024 (English)In: TAPPI Journal, ISSN 0734-1415, Vol. 2024-February, p. 113-122Article in journal (Refereed) Published
Abstract [en]

Processes that convert paperboard into finished products include, for example, printing, where the paperboard is subjected to rapid Z-directional (ZD) compression in the print nip. However, measuring and evaluating the relevant properties in the thickness direction of paperboard are not necessarily straightforward or easy. Measuring at relevant, millisecond deformation rates further complicates the problem. The aim of the present work is to elucidate some of the influences on the compressive stiffness. Both the initial material response and the overall compressibility of the paperboard is studied. In this project, the effect on the material response from the surface structure and the millisecond timescale recovery is explored. The method utilized is a machine called the Rapid ZD-tester. The device drops a probe in freefall on the substrate and records the probe position, thus acquiring the deformation of the substrate. The probe is also allowed to bounce several times on the surface for consecutive impacts before being lifted for the next drop. To investigate the time dependent stiffness behavior, the probe is dropped several times at the same XY position on the paperboard from different heights, thus achieving different impact velocities. The material response from drops and bounces combined allows study of the short-term recovery of the material. The material in the study is commercial paperboard. The paperboard samples are compared to material where the surface has been smoothed by grinding it. Our study shows that there is a non-permanent reduction in thickness and a stiffening per bounce of the probe, indicating a compaction that has not recovered in the millisecond timescale. Additionally, a higher impact velocity has an initial stiffening effect on the paperboard, and this is reduced by smoothing the surface.

Place, publisher, year, edition, pages
Technical Assoc. of the Pulp and Paper Industry Press, 2024
Keywords
Compaction; Drops; Measuring Instruments; Potassium Hydroxide; Recovery; Stiffness; Compaction; Drops; Grinding (machining); Potassium hydroxide; Probes; Recovery; Compressive stiffness; Deformation rates; Finished products; Impact velocities; Material response; Out-of-plane compression; Probe position; Property; Thickness direction; Time-scales; Stiffness
National Category
Materials Engineering
Identifiers
urn:nbn:se:ri:diva-72832 (URN)10.32964/TJ23.2.113 (DOI)2-s2.0-85186394941 (Scopus ID)
Available from: 2024-04-29 Created: 2024-04-29 Last updated: 2024-04-29Bibliographically approved
Hagman, A. (2023). Mechanical and repulpability assessment of four recycled demo streams, a study. In: Rock the Roll: Unleashing the Harmonies of the Paper Industry: . Paper presented at TAPPICon 2023. Cleveland, USA: TAPPI Press
Open this publication in new window or tab >>Mechanical and repulpability assessment of four recycled demo streams, a study
2023 (English)In: Rock the Roll: Unleashing the Harmonies of the Paper Industry, Cleveland, USA: TAPPI Press , 2023Conference paper, Published paper (Refereed)
Abstract [en]

In this study, oriented lab-sheets were produced from four different streams of base material. The reference stream was a blend virgin hardwood and softwood fibers, 50% of each. The three other streams were made of recycled material. The first recycled stream was a pure stream of unused paperboard, corresponding to “clippings”. The second recycled stream was composed of a selection of used corrugated boxes as well as some test liner. The third and final recycled stream was made to match a “1.02 quality” and consisted of 30% each of the other recycled streams and 40% journal paper. The streams were assessed with respect to repulpability (rejects, yield, adhesiveness, and visual inhomogeneity). The lab-sheets produced from each stream were evaluated through extensive mechanical testing at standard climate 23°C and 50% RH. The tests included: tensile tests, SCT, ZD-tension and compression, BCT on converted boxes and bending. Tensile tests were also performed on dried out samples as well as samples that had been conditioned at 90% RH. The repulpability study indicated that all three recycled streams had a high yield, with low amounts of adhesiveness and inhomogeneities. The mechanical testing showed, as expected, that the sheets from all three recycled streams had, overall, much lower values for the measured properties then the sheets from the virgin stream. The sheets from the clippings-stream performed better from a mechanical perspective then the sheets from the other recycled streams which were quite similar in their performance. By testing three realistic but well-behaved recycled streams, a benchmark has been created which can be used as reference data for future assessments of recycled fibers from different sources. 

Place, publisher, year, edition, pages
Cleveland, USA: TAPPI Press, 2023
Keywords
Adhesives; Bending tests; Paper and pulp industry; Recycling; Base material; Corrugated box; Hardwood fibers; Hardwoods ands; Inhomogeneities; Mechanical; Recycled materials; Reference streams; Repulpability; Softwood fibers; Tensile testing
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-68130 (URN)2-s2.0-85175850535 (Scopus ID)
Conference
TAPPICon 2023
Available from: 2023-11-30 Created: 2023-11-30 Last updated: 2024-01-03Bibliographically approved
Hagman, A. & Trost, T. (2023). Perforations on different corrugated flute grades and their effect on packaging performance. In: : . Paper presented at ISTA 2023 European Packaging Symposium.
Open this publication in new window or tab >>Perforations on different corrugated flute grades and their effect on packaging performance
2023 (English)Conference paper, Oral presentation with published abstract (Other academic)
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-69350 (URN)
Conference
ISTA 2023 European Packaging Symposium
Available from: 2024-01-10 Created: 2024-01-10 Last updated: 2024-01-10Bibliographically approved
Thorman, S., Rydefalk, C., Hagman, A. & Granlöf, L. (2023). Rapid, Out-Of-Plane Compression of Paperboard – Influence of Impact Velocity on The Surface. In: TAPPICon 2023 - "Rock the Roll: Unleashing the Harmonies of the Paper Industry": . Paper presented at TAPPICon 2023 - Rock the Roll: Unleashing the Harmonies of the Paper Industry. Cleveland, USA. 28 April 2023 through 1 May 202. TAPPI Press
Open this publication in new window or tab >>Rapid, Out-Of-Plane Compression of Paperboard – Influence of Impact Velocity on The Surface
2023 (English)In: TAPPICon 2023 - "Rock the Roll: Unleashing the Harmonies of the Paper Industry", TAPPI Press , 2023Conference paper, Published paper (Refereed)
Abstract [en]

Industry processes, such as printing, subjects paperboard to rapid, Z-directional compression. However, measuring and evaluating the relevant properties in the thickness direction are not necessarily straight forward or easy. Measuring at relevant, millisecond, deformation rates complicate the problem further. The aim of the present work is to elucidate on some of the influences on the compressive stiffness. Both the initial material response and the overall compressibility of the paperboard is studied. In this project the effect on the material response from the surface structure and the millisecond time-scale recovery is explored. The method utilized is a machine called the Rapid ZD-tester. The device drops a probe in free fall on the substrate and records the probe-position, thus acquiring the deformation of the substrate. To investigate the time dependent stiffness behavior the probe is dropped several times at the same xy-position on the paperboard from different heights, thus achieving different impact velocities. The probe is also allowed to bounce several times on the surface before lifted for consecutive drops. The drop-bounce cycle allows study of the short-term recovery of the material. The material in the study is commercial paperboard. The paperboard samples are compared to material where the surface has been smoothed by grinding it. Our study shows that there is a non-permanent reduction in thickness and a stiffening per bounce of the probe, indicating a compaction that has not recovered in the millisecond timescale. Additionally, a higher impact velocity has an initial stiffening effect on the paperboards, and that this is reduced by smoothing the surface.

Place, publisher, year, edition, pages
TAPPI Press, 2023
Keywords
Compaction; Grinding (machining); Potassium hydroxide; Recovery; Stiffness; Compressive stiffness; Deformation rates; Free fall; Impact velocities; Industry process; Material response; Out-of-plane compression; Property; Thickness direction; Time-scales; Probes
National Category
Materials Engineering
Identifiers
urn:nbn:se:ri:diva-68042 (URN)2-s2.0-85175872990 (Scopus ID)
Conference
TAPPICon 2023 - Rock the Roll: Unleashing the Harmonies of the Paper Industry. Cleveland, USA. 28 April 2023 through 1 May 202
Available from: 2023-11-23 Created: 2023-11-23 Last updated: 2023-12-27Bibliographically approved
Marin, G., Hagman, A., Östlund, S. & Nygårds, M. (2023). Torsional and compression loading of paperboard packages: Experimental and FE analysis. Packaging technology & science, 36(1), 31-44
Open this publication in new window or tab >>Torsional and compression loading of paperboard packages: Experimental and FE analysis
2023 (English)In: Packaging technology & science, ISSN 0894-3214, E-ISSN 1099-1522, Vol. 36, no 1, p. 31-44Article in journal (Refereed) Published
Abstract [en]

The present study investigates torsional and compressive loading of a paperboard package. Finite element (FE) analyses simulating the tests were performed to improve understanding of the stresses and deformations in the paperboard during loading. A simple experimental characterization of the necessary material properties could be performed to represent the multi-ply paperboard as a single-ply structure. The results from the single-ply model were compared with a laminate model, and the differences between the models were small. Comparing experimental and FE simulations of box compression and torsion showed that the FE models could accurately predict the response curves. However, in the simulations, there was an overprediction of the maximum compressive force and maximum torque, which was expected since geometrical imperfections and the heterogeneous internal structure of the material were not accounted for in the material model or the FE model. Local yield lines formed at the onset of non-linearities in the package load–displacement curves. Therefore, the strength of the paperboard affects the maximum compressive strength and maximum torque, and the bending stiffness of the paperboard only had a minor effect. When a first local maximum was reached, the number of FE that reached the failure stress increased exponentially. The simulations also showed that box compression was not an effect of package height, but higher packages had a lower maximum torque. © 2022 The Authors. 

Place, publisher, year, edition, pages
John Wiley and Sons Ltd, 2023
Keywords
box compression test, FE simulations, material characterization, paperboard, torsion test, Compression testing, Compressive strength, Finite element method, Paperboards, Torsion testing, Box compression tests, Compression loading, Finite element analyse, Finite element modelling (FEM), Finite elements simulation, Materials characterization, Maximum torque, Single ply, Torsional loadings, Torsional stress
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-61235 (URN)10.1002/pts.2693 (DOI)2-s2.0-85140254770 (Scopus ID)
Note

Correspondence: Gustav Marin, RISE Research Institutes ofSweden AB, Gothenburg, Sweden. Funding information: STFIs Association of Interested Parties.

Available from: 2022-12-01 Created: 2022-12-01 Last updated: 2023-11-01Bibliographically approved
Hagman, A. & Trost, T. (2022). Perforations on Boxes - Technical Aspects. In: : . Paper presented at ISTA European Packaging Symposium 2022, Berlin 4-5 October 2022.
Open this publication in new window or tab >>Perforations on Boxes - Technical Aspects
2022 (English)Conference paper, Oral presentation only (Other academic)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:ri:diva-62395 (URN)
Conference
ISTA European Packaging Symposium 2022, Berlin 4-5 October 2022
Available from: 2023-01-05 Created: 2023-01-05 Last updated: 2023-06-08Bibliographically approved
Björk, E., Muhic, D., Hagman, A. & Halonen, H. (2022). Stock Preparation as a Key Operation for Making High-Quality Wet Moulded Fibre Products. In: TAPPICon Conference 2022: . Paper presented at TAPPICon 2022. TAPPI Press
Open this publication in new window or tab >>Stock Preparation as a Key Operation for Making High-Quality Wet Moulded Fibre Products
2022 (English)In: TAPPICon Conference 2022, TAPPI Press , 2022Conference paper, Published paper (Refereed)
Abstract [en]

In the global pursuit for sustainable packaging solutions, usage of different paper raw material is one of the key components to fulfil the goal. Moulded fibre products allow usage of different fibre raw material, although for today, with some restrictions. For example, recycled fibre is of varying quality and can be a challenging material to use for thermoformed wet moulding applications. Further, CTMP strength potential should be further utilized for this application. In both cases, the stock preparation is crucial. The relationship between fibre type, stock preparation, processing and performance needs to be investigated to define how to best produce high-quality wet moulded fibre products using a specific fibre type. To be able to study this a laboratory equipment for manufacturing of high-quality wet moulded fibre products has been set up. Moreover, two test methods to evaluate properties important for trays have been developed; one to evaluate how much load the tray can take and one to evaluate how much the tray will warp during handling. Together with an optimised stock preparation for different fibre raw materials studies can be performed, which aim at increased usage of fibre qualities such as recycled fibre or CTMP for high-quality moulded fibre products. 

Place, publisher, year, edition, pages
TAPPI Press, 2022
Keywords
Fibers; Laboratories; Fiber raw materials; Fiber types; High quality; Key operations; Molding applications; Moulded fiber products; Packaging solutions; Recycled fibers; Stock-preparation; Sustainable packaging; Recycling
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-68102 (URN)2-s2.0-85175636848 (Scopus ID)
Conference
TAPPICon 2022
Available from: 2023-12-07 Created: 2023-12-07 Last updated: 2023-12-07Bibliographically approved
Hagman, A. & Rydefalk, C. (2022). ZD – Directional Testing of Paperboard, Using Refined Methods to Revisit Out of Plane Properties. In: TAPPICon 2022 Proceedings: . Paper presented at TAPPICon 2022.
Open this publication in new window or tab >>ZD – Directional Testing of Paperboard, Using Refined Methods to Revisit Out of Plane Properties
2022 (English)In: TAPPICon 2022 Proceedings, 2022Conference paper, Published paper (Refereed)
Abstract [en]

The ZD-tensile strength is tested by attaching the top and bottom sides of a paperboard to rigid blocks that are pulled apart. In a production laboratory the strength is recorded using a tape as an adhesive. In specialized laboratories a more thorough method is available that also measures the force-displacement curve of the sample. The advanced method involves laminating and gluing the paperboard sample to metal blocks which are mounted in a universal testing machine. 

In this study the advanced ZD-tensile method was refined by removing the glue step and laminating the paperboard directly to the blocks. The new method was validated against the regular method with adequate results. The limits of the refined method were explored with regards to ZD-strength and paper/paperboard thickness. 

In an attempt to unify the ZD-tensile and -compressive behaviour of paperboard, samples were laminated and tested in combined compression and tension testing. The compressive properties were compared to non-laminated samples. The laminated samples showed a different behaviour than the non-laminated samples. The flat slope seen in the initial part of the pure compression curve disappeared, replaced by a continuous response passing 0 N. The stiffness in this region resembled the response in tensile testing. 

Keywords
paperboard, ZD-compression, ZD-tensile, experimental
National Category
Applied Mechanics
Identifiers
urn:nbn:se:ri:diva-67102 (URN)
Conference
TAPPICon 2022
Available from: 2023-09-13 Created: 2023-09-13 Last updated: 2023-12-08Bibliographically approved
Hagman, A. (2019). Evaluation of moulded pulp trays using compression test and novel twist test. In: 29th IAPRI Symposium on packaging, 2019: Serving society innovative perspectives on packaging. Paper presented at 29th IAPRI Symposium on packaging, 11-14 June, 2019, Enschede, The Netherlands.
Open this publication in new window or tab >>Evaluation of moulded pulp trays using compression test and novel twist test
2019 (English)In: 29th IAPRI Symposium on packaging, 2019: Serving society innovative perspectives on packaging, 2019Conference paper, Published paper (Other academic)
Abstract [en]

Within the industry there exists great experience of producing moulded pulp trays,this includes adjusting process parameters to achieve a consistent output from thetray making machines. However, the evaluation of the results is at this point based onhands on methods that ultimately relies on subjective opinions of what makes a goodtray. This includes visual inspection of the trays, as well as a twisting the trays by handto evaluate stiffness. Such methods might suffice to achieve a consistent output, butare not suited for structured development work, which requires objective measures.One obvious measurement is a compression test, like a box compression test. However, this test does not tell the whole story, and differs from the hands-on tests usedtoday. Because of this a twist test was developed to emulate the hands-on testingpresently used to assess the quality of moulded pulp trays. The test is performed in atensile tester, by putting the tray in a sample holder which supports two diagonal bottom corners while a beam is pressing against the opposite upper diagonal corners.This forces the tray to bend.Plotting the results from these two tests against each other, results in a practicalgraph that can be used to evaluate both pulp and process properties, as well as trayweights. This plot reveals that some information remains hidden if only compressiontests are performed.Finally, such a graph lends itself to define boundaries for what is an acceptable tray.

Keywords
moulded pulp, tray, test method, compression test, twist test
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-39738 (URN)
Conference
29th IAPRI Symposium on packaging, 11-14 June, 2019, Enschede, The Netherlands
Available from: 2019-08-14 Created: 2019-08-14 Last updated: 2023-05-09Bibliographically approved
Srinivasa, P., Nygårds, M., Hagman, A., Pendergraph, S. & Sundström, J. (2019). On the torsion method for measurement of out-of-plane shear properties. In: International Paper Physics Conference 2019: preprint proceedings. Paper presented at International Paper Physics Conference 2019, Indianapolis, IN, USA, 5-8 May 2019; PaperCon 2019 (pp. 8-13). TAPPI Press
Open this publication in new window or tab >>On the torsion method for measurement of out-of-plane shear properties
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2019 (English)In: International Paper Physics Conference 2019: preprint proceedings, TAPPI Press, 2019, p. 8-13Conference paper, Published paper (Other academic)
Abstract [en]

Torsional loading with combined out-of-plane compressive loading has been studied for its viability in measurement of out-of-plane shear properties. Paperboards of two qualities were evaluated, namely paperboard A, which was a multiply, while paperboard B was a single ply. Both paperboards were produced on commercial paperboard machines. A total of 24 samples were prepared, 12 of each quality, which were tested under four different load levels. Three different out-of-plane compressive load levels were tested in addition to test without compressive load. Results have been presented from the successful tests in terms of torque versus angle of torsion and shear stress versus shear strain plots. It has been demonstrated that the technique was suitable for out-of-plane shear measurements. An order of magnitude agreement in the values of the properties was obtained in the torsional test method and the rigid block shear tests. Results indicated a possible stable post-peak response in shear loading at sample sizes that would provide material properties comparable with that of a homogeneous test. The torsional setup offered benefit of ease of applying out-of-plane axial loads, both in compression and tension.

Place, publisher, year, edition, pages
TAPPI Press, 2019
Keywords
paperboard, board properties, failure mode analysis, torsion test, shear stress, torque, multiply board
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:ri:diva-43252 (URN)
Conference
International Paper Physics Conference 2019, Indianapolis, IN, USA, 5-8 May 2019; PaperCon 2019
Available from: 2020-01-15 Created: 2020-01-15 Last updated: 2023-05-09Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-0848-4305

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