Triangular mesh offset aiming to enhance fused deposition modeling accuracy

Fused Deposition Modeling is a worldwide diffused Additive Manufacturing technology able to fabricate prototypes, tooling and end user parts directly from a virtual model. The layer by layer fabrication allows having no limitation of part shape complexity but some weaknesses exist about the obtainable accuracy. The dimensional deviations observed on a physical prototype are of the order of some tenths of millimeter depending upon the local slope of the surface. In order to enhance the accuracy, the idea is to compensate for the deviations by means of a virtual model offset. For the purpose a novel methodology has been developed to offset the triangular mesh: it operates an offset with a variable radius of the vertices without changing their interconnections. In this way the new virtual model is generated in a stable and robust way without modifying the Fused Deposition Modeling process chain. The experimentation carried out both on simple and complex geometries points out a marked improvement of the dimensional accuracy. The assessment has been performed by dimensional measurements and by a preliminary analysis of the errors introduced by the offset method.