Fiber Bragg grating based investigation of residual strains in ABS parts fabricated by fused deposition modeling process

Fused deposition modeling (FDM) is a process by which functional parts can be rapidly produced by sequential deposition of fused material layers. Various severe inaccuracies such as curl and warp distortions and delaminations are attributed to residual stresses and strains build up during the fabrication process. Their magnitude is largely influenced by the selected process parameters. This study investigates the magnitude of the solidification induced residual strains in FDM fabricated parts using different processing parameters. Two important parameters were considered: (a) layer thickness and (b) deposition orientation. The developed residual strains at the end of the fabrication process were recorded using an optical sensor with a short fiber Bragg grating (FBG) embedded at the midplane of FDM built specimens. The same specimens were additionally subjected to a thermal cycle where the coefficient of thermal expansion (CTE) of the ABS material was measured using the FBG sensor.

► A FBG sensor was used to obtain in situ the solidification induced residual strains.
► The residual strains were significant and sensitive to the build (road) orientation.
► Thermal treatment above material’s Tg led to an increase of solidification strains.
► The coefficient of thermal expansion was measured using the same FBG sensor.