https://popups.uliege.be/esaform21/index.php?id=1261 Index terms fr 0 https://popups.uliege.be/esaform21/index.php?id=4641 The objective of the present work is to study the raster generation to realize Fused Filament Fabrication parts. The research in this paper focused on the evaluation of the deposition of a simple geometry with a FFF machine, supported by an analytical model to compute the build time, also evaluating the geometrical variations caused by changes in process parameters. The main parameters were the print temperature and speed as a function of the thermal and rheological properties of the PLA filament. The study identified essential correlations between process parameters, raster dimensions, and filament properties. An experimental procedure, supported by an analytical model, was implemented for computing raster time and material dimensions. Wed, 07 Apr 2021 18:37:25 +0200 Wed, 07 Apr 2021 18:37:31 +0200 https://popups.uliege.be/esaform21/index.php?id=4641 https://popups.uliege.be/esaform21/index.php?id=2335 Automated fiber placement processes could be combined with additive manufacturing to produce more functionally complex composite structures with more flexibility. The challenge is to add functions or reinforcements to PEEK/carbon composite parts manufactured by automated fiber placement process, with additive manufacturing by fused filament fabrication. This consists of extruding a molten polymer through a nozzle to create a 3D part. Bonding between polymer filaments is a thermally driven phenomenon and determines the integrity and the final mechanical strength of the printed part. 3d-printing high performance polymers is still very challenging because they involve high thermal gradients during the process. The purpose of this work is to find a process window where the bonding strength is maximized between the composite laminate and the first layer of printed polymer, and inside the printed function as well. Experimental measurements of the temperature profiles at the interface between a composite substrate and 3d-printed PEI under different processing conditions were carried out. The interface was observed using microscopic sections. The methodology for studying the impact of printing parameters on the cohesion and adhesion of printed parts with a composite laminate is described. This work provides insights about the influence of processing conditions on the bond formation between high-performance polymer surfaces. It highlights the importance of controlling the thermal history of the materials all along the process. Tue, 23 Mar 2021 16:58:33 +0100 Tue, 30 Mar 2021 10:21:28 +0200 https://popups.uliege.be/esaform21/index.php?id=2335 https://popups.uliege.be/esaform21/index.php?id=2495 The market segment of additive manufacturing is showing an annual growth of more than ten percent, with extrusion-based processes being the larger segment of the market. The scope of use is limited to secondary structures. Equipment manufacturers try to guarantee constant material characteristics by closed systems. The characteristic values are up to 50% below the ones from injection molding. The processing of high-performance polymers with reinforcing fibers is an additional challenge. Further development requires an opening of the material and manufacturing systems. The guidelines and standardization for this are still missing. For this reason, a functional analysis (FA) according to TRIZ ("theory of the resolution of invention-related tasks") is performed within this study. This identifies the undesired functions and quantifies their coupling with process components and parameters. In the FA, the manufactured part is the target component in order to address its quality. This way the FA identifies five undesirable functions in the process. These are: deform, cool, weaken, swell and shape. For hightemperature thermoplastics, thermal shrinkage is the primary cause of geometric tolerance. Therefore, the deformation is largely dependent on the cooling mechanism. For a detailed analysis, the polymer melt is further disassembled. The results are six sub-components. The weakening is mainly due to the physical phase of the voids, which exists during the entire processing. The breakdown comprises physical fields such as stress, temperature and flow. These determine the output properties as well as the bonding between the layers. The associated functions are the swelling and shaping. In order to generate broadly applicable standardizations, research questions for further investigation are derived from this study. Tue, 23 Mar 2021 20:43:30 +0100 Sun, 28 Mar 2021 15:06:39 +0200 https://popups.uliege.be/esaform21/index.php?id=2495