Development of a combined analytical and experimental approach for the determination of the cohesive strength between material extrusion layers using the true area of contact

• Published in: Additive manufacturing Vol. 30; p. 100832
• Main Authors: Phan, Thao Thi Phuong, Phan, The Quang, Sherif El-Gizawy, Ahmed
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2019
• Subjects: Cohesive strength; Effective second moment of inertia ratio; Material extrusion; Three-point bending; True area of contact; Material extrusion; Three-point bending; Cohesive strength; Effective second moment of inertia ratio; True area of contact
• ISSN: 2214-8604; 2214-7810
• DOI: 10.1016/j.addma.2019.100832

[Display omitted] •A combined analytical and experimental approach to determine the cohesive strength between layers using true area of contact has been developed.•The accuracy of the introduced model was verified by comparing its bending test results with different build parameters.•A reduction of density results in a reduction of the apparent cohesive strength and an increase on the true cohesive strength in the study.•Failure between layers can occur at both interface and inside the raster observed from the bending test. Material Extrusion (ME) is a type of Additive Manufacturing (AM) process that creates parts by depositing polymer filaments in successive layers. The strength of ME products depends on both the cohesive strength between layers and between rasters. The raster gap is the most significant process factor affecting the strength of ME built parts. Standard tensile tests with a dog-bone shaped specimens are not suitable to determine the strength between layers of the ME built parts. A new model is introduced to predict the cohesive strength between layers using the true area of contact which can be obtained from the apparent values taken from mini three-point bending tests. The accuracy of the introduced model was verified by comparing its bending test results with different build parameters, the applicability and promise of the introduced model were confirmed.