Investigation of manufacturing defects in 3D-printed CFRP using laser ultrasonic testing and x-ray micro-computed tomography

Abstract

3D-printed carbon fiber reinforced plastic (CFRP) composites have attracted significant attention due to their design flexibility and low manufacturing cost. However, 3D-printed CFRP contains inherent defects that occur during the manufacturing process. As the manufacturing defects are likely to degrade the mechanical performance of the 3D-printed CFRP, these defects require extensive investigation. Typically, x-ray micro-computed tomography (micro-CT) is used to detect manufacturing defects, but as micro-CT cannot be applied to large structures, the laser ultrasonic testing (LUT) method has been proposed. In this study, two specimens with different stacking sequences were manufactured using a continuous fiber 3D printer. The two specimens were then inspected using LUT and micro-CT. The manufacturing defects were successfully visualized using LUT, and similar defects were detected in the micro-CT inspection results. The size, location, and shape of the detected defects were evaluated by comparing the LUT and micro-CT inspection results. Consequently, the LUT method showed a performance comparable to that of micro-CT for detecting the manufacturing defects of 3D-printed CFRP. Since the LUT is capable of inspecting large scale 3D-printed composites, it will be absolutely advantageous in real world applications.

Investigation of bending performance of printed continuous carbon fiber reinforced polylactic acid using acoustic emission

“…The correlation coefficient matrix is expressed by Equation (7), and each element in the correlation coefficient matrix is calculated by Equation (8).…”

“…Manufacturing defects in 3D printing composite was investigated through laser ultrasonic testing and x‐ray micro‐computed tomography. [ 8 ] Fiber misalignment and breakage during 3D printing process was also analyzed. [ 9 ] The bending strength and bending modulus of 3D printed composites with a print layer thickness ranging from 0.3 to 0.8 mm were investigated [ 10 ] and the bending mechanical behavior and damage of 3D printed composites was also investigated.…”

Noncontact nondestructive ultrasonic techniques for manufacturing defects monitoring in composites: a review

“…In addition, noncontact methods reduce any extra labor and time required for installation and maintenance of traditional contact transducers, while also diminishing the use of consumables. As was mentioned in the previous section “Ultrasonic monitoring techniques,” the commonly used noncontact type transducers are EMATs, 134 PL, 135–138 and ACT. 120 EMATs generally cannot be applied to composite materials and are limited to metallic/magneto-strictive structures as these conductive structures allow the traveling of eddy current on their surface generated by the AC current in the electric coil.…”

Structural and Dimensional Analysis by Computed Tomography of Multi Geometric Template Manufactured by Fused Deposition Modeling

“…Khosravany & Reinicke [49] presented a summary of industrial and academic applications, models created with different additive manufacturing processes or techniques in different materials and shapes to analyze porosity and material density mainly, all with regular geometries or with repetitive manufacturing patterns. On the other hand, Cho & Lee [50] presented the use of CT for porosity and material density analysis of a dog-bone-shaped specimen printed in Carbon fiber reinforced plastic.…”