Nip Mechanics of Flexo Post-printing on Corrugated Board

Holmvall, Martin; Uesaka, Tetsu

doi:10.1177/0021998307074135

Cited by 4 publications

(11 citation statements)

References 5 publications

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“…In order to investigate the effects of deformations of the corrugated board structure systematically, a 3D fi nite element model (see Figure 4) was constructed using ANSYS commercial software (SAS IP Inc., Canonburg, PA, USA). 14,15 The model was based on a previous study, 7 constructed with eight-node SOLID185 elements. This model however included possibilities to distort the Bfl ute corrugated board over several fl ute lengths.…”

Section: Figure 3 Non-uniform Striping On a Full-tone Printed Bfl Utmentioning

confidence: 99%

“…The material parameters used in the model are presented in Table 1. Symmetry boundary conditions were used for the front side, along the nip centre line and the left side of the model in 7 200 mm. The mesh density was chosen so that the results did not change more than 5% when the mesh density was increased by a factor of two.…”

Section: Figure 3 Non-uniform Striping On a Full-tone Printed Bfl Utmentioning

confidence: 99%

“…Striping in fl exo post-printing has been studied by a few authors. [3][4][5][6][7][8] Netz 3 developed a non-contact instrument for measuring the topography of corrugated boards, specifi cally, the washboarding. Netz also performed printing experiments on corrugated board.…”

Section: Introductionmentioning

confidence: 99%

“…An optimum design showed that not only a thinner photopolymer, but also specifi c materials properties of the cushion, are required. 7 (Deformable cushion or photopolymer is not the solution to eliminate the pressure variations.) Previous studies 7,8 were performed for full-tone printing of a fl at corrugated board (except in the case of the washboarding study).…”

Section: Introductionmentioning

confidence: 99%

“…7 (Deformable cushion or photopolymer is not the solution to eliminate the pressure variations.) Previous studies 7,8 were performed for full-tone printing of a fl at corrugated board (except in the case of the washboarding study). However, topography measurements have shown that seemingly fl at corrugated boards have signifi cant distortions other than washboarding (see Figure 2), e.g.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Print uniformity of corrugated board in flexo printing: effects of corrugated board and halftone dot deformations

Holmvall

Uesaka

2008

Packag Technol Sci

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Print non-uniformity is a major concern for fl exo post-printers. Many of these nonuniformities are suspected to be caused by the corrugated board structure itself. Striping is the most obvious one, but also other print quality problems might be structure-related. This work focuses on how deformations of the board might lead to print non-uniformities, and if the deformation of halftone dots is the mechanism behind striping in halftone fl exo post-printing. Finite element models were used to analyse the effects of deformations of corrugated boards and compressed halftone dots in the printing nip. Distortions of the board due to non-uniform hygro-thermal strains were shown to be a potential cause of print non-uniformities. Striping in halftone prints was found to be caused by differences in dot gain between areas above ridges and valleys of the fl ute structure.

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Section: Figure 3 Non-uniform Striping On a Full-tone Printed Bfl Utmentioning

confidence: 99%

Section: Figure 3 Non-uniform Striping On a Full-tone Printed Bfl Utmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Print uniformity of corrugated board in flexo printing: effects of corrugated board and halftone dot deformations

Holmvall

Uesaka

2008

Packag Technol Sci

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Predicting creep lifetime performance in edgewise compression of containerboards and for stacked corrugated board boxes

Holmvall¹

2021

Packag Technol Sci

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Predicting how long time a corrugated board box can be stored with a constant load stacked on top of it without failing is an everyday challenge for a box designer. This is a basic step in corrugated board box material design which is usually resolved by utilizing so-called stacking factors. A stacking factor is the ratio between the compression strength of the box and the stacking load. Higher stacking factors are used to accommodate for longer storing times or high relative humidity conditions. Utilizing stacking factors in the way commonly done today can be a good first approximation. However, this method often neglects or overcompensates for the inherent nonnormal distribution statistical behaviour associated with corrugated board box lifetimes. A higher precision in predicting box lifetimes enables material optimization and, thus, a more efficient use of resources. This work presents a convenient way of predicting lifetimes of both containerboards and corrugated board boxes. The approach additionally introduces the concept of reliability into lifetime prediction.The prediction is made directly from material or structural parameters and the applied load. This is accomplished by relating two different parameter sets for the Weibull distribution. It is shown that lifetime is indeed dependent not only on a stacking factor but also on durability and the variations associated with the material or box.

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Printing Dynamics: Nip Pressure and Its Relationship with Materials’ Viscoelasticity

2020

J Package Technol Res

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A theoretical framework of nip dynamics of conventional printing, including dynamic models deducted from nip geometry, printing speed, and physics laws, is proposed. Different from previous works, the present work focuses at obtaining the nip pressure from a given nip geometric setting, the common way in full-scale printing. The effects of viscoelastic characteristics of paper substrate and print form (rubber and/or polymer) on the nip pressure, which become pronounced in a full-scale printing process due to high speed, are accounted and illustrated by three physical models, e.g., Maxwell model, Kelvin-Voigt model, and Burgers model. Details of the nip dynamic features, shape, amplitude, duration, and effective nip width, etc., have been worked out. The viscoelastic nature of the materials was found to be responsible for the so-called speed-hardening, asymmetric nip profile, variations in the nip amplitude and effective nip width, etc. It was also found that how the viscoelastic properties of the materials affect the nip dynamics depend on the how the elastic components and the viscos count parts are connected with each other. The framework is applicable to calendaring, gravure, offset, and flexography.

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Nip Mechanics of Flexo Post-printing on Corrugated Board

Cited by 4 publications

References 5 publications

Print uniformity of corrugated board in flexo printing: effects of corrugated board and halftone dot deformations

Print uniformity of corrugated board in flexo printing: effects of corrugated board and halftone dot deformations

Predicting creep lifetime performance in edgewise compression of containerboards and for stacked corrugated board boxes

Printing Dynamics: Nip Pressure and Its Relationship with Materials’ Viscoelasticity

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