PSI - Issue 59

O.M. Zaika et al. / Procedia Structural Integrity 59 (2024) 786–792

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O.M. Zaika et al. / Structural Integrity Procedia 00 (2019) 000 – 000

The process of 3D printing involves additional costs, including electricity, materials and staff time spent on the printing process. The cost of repeate d 3D printing can be estimated at €3,000 per month, taking into account the number of printers and the number of defective parts before optimisation. Calculation of thermal processes during 3D printing is a key stage in the production of parts and other objects using 3D printers. In order to ensure the suc cessful production of high quality and reliable parts, it is essential to take into account the various thermal parame ters and the influence they have on the printing process. One of the most important factors influencing the thermal processes involved in 3D printing is the choice of ma terial to be printed on. Each material has different thermal properties, such as coefficient of thermal conductivity, temperature limits and heat capacity, which need to be taken into account in the calculation of thermal processes. The PRUSA 3I printer has been implemented at Kromberg & Schubert. It is a model that is widely used in vari ous companies around the world. The most commonly used material is PETG with a thickness of 1.75 mm and a 40% infill. Uniform printing parameters for all parts include a layer height of 0.2 mm, vertical wall perimeters of 2 mm and a solid horizontal layer thickness of 5 layers. Critical temperature parameters include a nozzle temperature of 220 °C and a bed temperature of 80°C. The density of the objects produced is set at 1.27 g/m 3 . Achieving uniform heating of the print bed is essential to ensure optimum adhesion to the part. Heating also serves another important purpose, which is to minimise the temperature gradient between the first printed layers and the subsequent layers. The lower layers tend to cool rapidly as the extruder moves further away from them with each successive layer. This rapid cooling can lead to deformation, potentially causing the model to warp at the edges or even detach from the print bed. To address these concerns, the recommended measures have been implemented in the following order: the shelves on which the 3D printers are positioned are securely mounted on a robust and rigid frame. This ensures that the geometric dimensions are maintained over time and eliminates any play or slack, regardless of various unpre dictable factors such as fluctuations in ambient temperature and humidity, as well as the vibrations that occur during printing. The shelves on the stand are carefully aligned to maintain a level surface, and the area where the 3D print ers are positioned is constructed from a durable, non-slip material. In addition, the platform is covered with a layer of rubber for added stability and performance. The 3D printers generate vibrations during operation, so their interaction has been minimised by maintaining a minimum distance of 10 cm between them. If a 3D printer programme is configured with high quality printing pa rameters, this results in smooth and slower movements. Conversely, if the part doesn't require high precision, the printing speed is increased, resulting in greater fluctuations in the process. In order to maintain the desired temperature conditions in the printing area, thermal protective covers have been installed. These enclosures have improved the quality of the objects produced and reduced energy consumption during the printing process. In Fused Deposition Modelling (FDM) printing, it is essential to achieve a balance in cooling to prevent the plastic from warping. It is necessary to cool the extruded plastic quickly while ensuring uni form cooling to avoid uneven cooling that can lead to thermal distortion. Failure to maintain temperature regimes during the printing process can result in damage during operation in production processes (Fig. 5).

Fig. 5. Broken holders for which temperature regimes were not observed during 3D printing.