Enhancing dimensional accuracy of FDM based biomedical implant replicas by statistically controlled vapor smoothing process

Abstract

The aim of the present study is to highlight the benefits of vapor smoothing on ABS replicas prepared by fused deposition modeling (FDM) for rapid casting of biomedical implants. The FDM process induced stair steps on circular and sloping surfaces, which increased part dimensions when measured and led to oversized parts (contrary to reduced part dimensions in linear surfaces).The process originally developed for surface finishing employs the technique of plastic reflowing of heated material, in contrast to material removal in traditional finishing processes. Measurements performed on CMM helped in evaluating the dimensional tolerances of replicas which emerged to be within limits for three cycles of vapor smoothing (each of 20 s). Similar parameter settings yielded the best surface finish, which supported the assumption of layer resettlement of the semi-liquid ABS material. The statistical analysis strongly indicated the vapor smoothing process to be statistically controlled.