The influence of the processing temperature of polylactide (PLA) on the structure geometry changing (SGC) and its functional properties were analyzed. The PLA samples subjected to testing were manufactured using incremental fused deposition modeling technology (FDM) with processing temperatures ranging from 180°C to 230°C. The topography of the PLA surfaces formed during heat dissipation and generated by the work table was analyzed. The roughness measurements were carried out using the profile method in accordance with PN ISO 3274: 2011. Registered profiles of the surfaces were analyzed numerically in fractal terms using the method of the S(Δx) structure function. The functional properties of the PLA surface were evaluated on the basis of Abbott-Firestone curves, according to PN EN ISO 13565–2: 1999.
3D printing in FDM (Fused Deposition Modelling) technology is commonly used, mainly in the preparation of prototypes, but also for the production of ready-made elements. Objects printed using the FDM method have characteristic, adverse surface features related to the limitations of this technology. That is why surface treatment of 3D prints becomes crucial. One of the method is metal plating of elements. The most frequently used material in FDM technology is PLA (polylactic acid) and ABS (acrylonitrile butadiene styrene). Study of surface parameters determination for ABS prints after galvanic copper plating is presented in this paper. For this purpose, samples printed with ABS were smoothed in acetone vapour. Most favorable parameters of the surface were obtained for samples that had contact with acetone vapour for 60 minutes. Ultimately, surface analysis of samples after graphite coating and subjected to copper plating was performed. It was found that surface parameters are close to results obtained with traditional methods of metal processing.
In this work, experiments were carried out to quantify the behaviour of friction stir welded (FSW) AA5082-AA7075 butt joints under tensile loading and completely reversed fatigue loading. Different samples were prepared to identify optimum tool rotational and travel speeds to produce FSW AA5082-AA7075 butt joints with the maximum fatigue life. ANOVA was performed, which confirmed that both tool speed and tool rotational speed affect the tensile strength of the weld. The samples exhibit a considerable difference in their fatigue life and tensile strength. This difference can be accounted to the presence of welding defects such as surface defects and porosity. S-N curve plotted for the sample shows a significantly high fatigue life at the lower stress ranges. Fracture surfaces were also analysed under scanning electron microscope (SEM). Study of the fracture surface of the sample that failed under fatigue loading showed that the surface was mainly divided in two zones. The first zone was the area of fatigue crack growth where each stress cycle, slowly and gradually, helped in the growth of the crack. The second zone was the region of fast fracture where the crack growth resulted in the failure of the joint instantaneously. The fracture surface study of the sample that failed under tensile loading showed that the mode of failure was ductile in nature.
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