Nondestructive Evaluation of Nylon/Carbon-Fiber Additively Manufactured Components using Rotational Eddy Current Testing

Polymer filament-based material extrusion additive manufacturing (AM), commonly referred to as fused filament fabrication (FFF), is a quickly growing method of production which specializes in custom components with geometrically complex features. Nondestructive testing (NDT) has the potential to play a vital role in advancing FFF to producing functional components for critical applications. To date, defects such as incomplete interlayer bonding,inter-layer void content, and intra-bead porosity content can all be present even under the most effective parameters. However, an inability to capture said defects through effective NDT strategies has limited the functional abilities of AM components. In this study, customized high-frequency Eddy Current Testing (ECT) has been used to characterize various aspects of as-manufactured AM components, such as raster orientation, fiber content and extrusion multiplier. The FFF process was used to generate single layer coupons using an Essentium HSE 180-HT. The effect of carbon fiber content as well as that of extrusion multiplier, which simulates varying amounts of inter-layer void content, on the ECT response of the samples was explored using a nylon filament feedstock with 15 wt% and 25 wt% carbon fiber content. The experiment displayed distinguishable results from EC scan data for individual samples which correlate with the varied printing parameters.