Void minimization in adhesive joints

Chester, R.; Roberts, J.D.

doi:10.1016/0143-7496(89)90107-3

Cited by 29 publications

(4 citation statements)

References 3 publications

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“…Defects in the adhesive gap caused by air pockets can have a significant negative effect on the strength of the bonded joint. Various publications deal with the formation mechanisms of air pockets (Guyott et al, 1986;Chester and Roberts, 1989;Davis and Bond, 1999), and conclude that air bubbles may already be present in the adhesive container or may be formed during application or squeezing, trapping areas with air. The effects of air pockets on the strength of adhesively bonded wind turbine blades have been studied in detail in Petryna et al (2014).…”

Section: Significance Of Air Entrapments In Adhesivesmentioning

confidence: 99%

Towards the efficient modelling of trapped air pockets during squeeze flow

Müller

Willenbrock

Stahl

et al. 2022

Exp. Comput. Multiph. Flow

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In most bonding processes, an adhesive is applied to a substrate in a specific pattern before the second substrate is subsequently pressed against it. During this, the adhesive flows in such a way that, ideally, it completely fills the joint. In practice, however, areas with entrapped air frequently remain in the bonded adhesive layer. Within the scope of a research project, these flows are systematically analyzed in order to identify optimal initial application patterns for the adhesive and substrate geometry to minimise such risks. For this purpose, the authors use an efficient flow model, the partially filled gaps model (PFGM), extended in this study to include the functionality of trapped air pockets. Depending on the volume fractions of air and adhesive, the flow of both phases is computed. Therefore, the model is introduced and fully described, benchmarked with respect to its plausibility and functionality, and results obtained are compared with a CFD calculation. Thereafter, the functionality of openings and closings of the pockets are analyzed. Lastly, the model is then applied to a real scenario created with a Hele-Shaw cell measurement. The benchmark as well as the comparison with the measurement results show the high potential of this technique.

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Section: Significance Of Air Entrapments In Adhesivesmentioning

confidence: 99%

Towards the efficient modelling of trapped air pockets during squeeze flow

Müller

Willenbrock

Stahl

et al. 2022

Exp. Comput. Multiph. Flow

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“…Taken with previous literature, the new search also revealed a wide range of silane drying conditions for the DSTO process: from ambient temperature to 80°C (176°F) to 110°C (230°F) to unknown (via heat gun). Use of elevatedtemperature drying appeared to be directed at moisture removal from the adherend surface to reduce porosity in the adhesive bondline as opposed to being a requirement for the silane treatment itself 21,22,23,24 .…”

Section: Initial Silane Surface Preparation Evaluationsmentioning

confidence: 99%

Grit-Blast/Silane (GBS) Aluminum Surface Preparation for Structural Adhesive Bonding

Mazza¹,

Avram²,

Kuhbander³

2003

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“…A number of studies have investigated the effects of bubbles on the mechanical strength and the reliability of adhesive joints or epoxy laminates. [2][3][4] According to these studies, mechanical strength and moisture absorption were affected by the formation of the bubbles. Therefore, it is possible that the formation of process bubbles during RS-FS bonding can reduce the mechanical property of the adhesion strength of ACF joints and induce moisture penetration and moisture entrapment during reliability tests in humid environments.…”

Section: Introductionmentioning

confidence: 97%

Study of the Formation of Bubbles in Rigid Substrate-Flexible Substrate Bonding Using Anisotropic Conductive Films and the Bubble Effects on Anisotropic Conductive Film Joint Reliability

Kim

Chung

Kwon

et al. 2007

Journal of Elec Materi

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The formation of process-related bubbles that become entrapped inside the anisotropic conductive film (ACF) layer during bonding processes remains an issue. The formation of these bubbles is strongly influenced by the process variables, such as bonding pressure and bonding temperature. Therefore, bonding process variables of bonding temperature, bonding pressure, and type of flexible substrate (FS) were changed in order to investigate the effects of the changes as they concern the formation of bubbles. According to the results, the tendency toward bubble formation was closely related to these three factors. The bubble area increased as the bonding temperature increased. Moreover, the shape and tendency of bubbles coincided with temperature distribution in the ACF layer. Two different types of FS, each with different surface roughnesses and energies, were used. The bubbles formed only on the FS with the larger roughness and lower surface energy. According to the results from a surface energy measurement of FS types using goniometry, a FS with a higher surface energy is favorable for a bubble-free assembly, as the higher surface energy provides better wettability. In addition, in order to investigate the effect of bubbles on the reliability of ACF joints, the pressure cooker test (PCT) was performed, and all samples with bubbles electrically failed after 72 h of a PCT, as the process-related bubbles provided a moisture penetration path and entrapment site for moisture. However, all type 1 test vehicles (TVs) survived even after 120 h of a PCT. Therefore, Ar and O 2 plasma treatments were performed on the FS with the lower surface energy in order to improve the surface energies and wettability. Following this, the bubbles were successfully removed at rigid substrate (RS)-FS bonding joints using ACFs.

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Void minimization in adhesive joints

Cited by 29 publications

References 3 publications

Towards the efficient modelling of trapped air pockets during squeeze flow

Towards the efficient modelling of trapped air pockets during squeeze flow

Grit-Blast/Silane (GBS) Aluminum Surface Preparation for Structural Adhesive Bonding

Study of the Formation of Bubbles in Rigid Substrate-Flexible Substrate Bonding Using Anisotropic Conductive Films and the Bubble Effects on Anisotropic Conductive Film Joint Reliability

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