Abstract

Currently, fused filament fabrication (FFF) additive manufacturing processes are limited by the dimensional and geometrical inaccuracies of manufactured parts. The need to make these technologies more competitive with conventional manufacturing processes has motivated numerous studies aimed at correcting manufacturing errors. To address this issue, this work proposes an online process monitoring approach based on digitizing deposited material layers to measure geometric errors and subsequently correct them by compensating the extrusion head trajectory.

Each deposited layer is digitized using a Contact Image Sensor (CIS), a technology commonly found in commercial document scanners. Given the difficulties involved in integrating these sensors into commercial additive manufacturing machines, a hardware-software system has been developed to operate the sensor on a test bench. In addition to performing additive manufacturing operations, the test bench integrates the CIS sensor to digitize the layers of parts during fabrication.

Digital image processing is required to extract measurements from the acquired images. Accordingly, different image processing strategies and super-resolution algorithms are investigated to generate higher-resolution images. The results demonstrate that the processed images provide sufficient quality for subsequent geometric measurements using contour detection and measurement algorithms.