Despite the advantages that additive manufacturing (AM) processes present and the progressive number of activity sectors that they emerge in, their successful adoption is currently hampered by defects in surface finish as well as dimensional and geometrical precision. This results in reduction of their suitability for net shape manufacturing, thereby, requiring the evaluation of their performances. Considering this notion, this paper deals with in-plane deviation modeling of material shrinkage occurring in fused deposition modeling (FDM) process. To achieve this aim, two models were developed, each for circular and squared shapes. The objective was to first understand the deviation behavior, then compare it with actual data extracted from a test part to find out the rates with which the shrinkage would be compensated, and finally based on the obtained results, the CAD file would be modified. The experimental findings showed the effectiveness of the adopted methodology and the ability of developed models to compensate for the deviation.

The innovative EPITHER process makes it possible to produce massive C/Thermoplastic composite parts with oriented continuous fibres in order to meet specific mechanical loading constraints for structural parts. This fibre orientation allows, as in the case of forging fibre pull-outs, to increase the mechanical strength of the composite product. Composite structural parts must also contribute to the reduction of CO2 emissions by reducing the weight of parts in mobile systems, particularly those in motion for power transmission. This process consists of two or three steps, the preforming necessarily for the placement and orientation of the continuous carbon fibre composites required to increase their characteristics, pre-consolidation and shaping. In this study, the first two steps are performed simultaneously by 3D printing. In order to obtain finished products with good dimensional and material characteristics. This study provides elements for optimizing certain process parameters and the associated results, particularly at different steps in the forming process. In addition, this paper focuses on the movement of the material of the parts obtained by the shaping process. It links proceeding conditions and health of the material: for example, by determining the void ratio, fibre ratio.

Purpose One major problem preventing further application and benefits from additive manufacturing (AM) nowadays is that AM build parts always end up with poor geometrical quality. To help improving geometrical quality for AM, this study aims to propose geometrical deviation identification and prediction method for AM, which could be used for identifying the factors, forms and values of geometrical deviation of AM parts. Design/methodology/approach This paper applied the skin model-based modal decomposition approach to describe the geometrical deviations of AM and decompose them into different defect modes. On that basis, the approach to propose and extend defect modes was developed. Identification and prediction of the geometrical deviations were then carried out with this method. Finally, a case study with cylinders manufactured by fused deposition modeling was introduced. Two coordinate measuring machine (CMM) machines with different measure methods were used to verify the effectiveness of the methods and modes proposed. Findings The case study results with two different CMM machines are very close, which shows that the method and modes proposed by this paper are very effective. Also, the results indicate that the main geometrical defects are caused by the shrinkage and machine inaccuracy-induced errors which have not been studied enough. Originality/value This work could be used for identifying and predicting the forms and values of AM geometrical deviation, which could help realize the improvement of AM part geometrical quality in design phase more purposefully.

Additive manufacturing (AM) became an advanced research topic due to its ability to manufacture complex shapes. But the ability to achieve predictable and repeatable shapes is critical. Therefore, to optimize the design of an additive manufactured product, tolerancing is a key issue. This paper focuses on geometrical quality assessment of an AM product. It includes a process oriented geometrical model to predict the surface roughness and dimensional deviations, and a geometrical simulation tool to assess the impacts of these deviations on the geometrical behaviour of the joint. An application of the approach is illustrated through a case study.

In the expanding context of device miniaturization, forming processes of ultra thin sheet metals are gaining importance. Numerical simulation of these processes requires accurate material modeling. In this study, both the phenomenological modeling approach and the crystal plasticity finite element method (CPFEM) are considered. Theoretical definitions of both models, numerical implementation as well as their parameter identification procedures are outlined. Subsequently they are compared on a one to one basis, mainly with regards to their ability to predict mechanical responses for a variety of strain loading paths.