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In the surface mount industry, microelectronic devices are reflow soldered to printed circuit boards with the benefit of mildly activated rosin (RMA) based fluxes. The residues from these fluxes, when not properly cleaned from the component boards, have been cited for decreased circuit life due to corrosion of the solder joints and loss of insulating resistance. Post‐solder cleaning operations with CFC (chlorofluorocarbon) solvents have been deemed environmentally harmful. Hence, there is a great need in the surface mount community for a no‐clean or fluxless solder reflow process. The BOC Group has developed a novel, proprietary process, by which circuit boards and their components are attached with a solder paste under a reactive fluxing atmosphere. The post‐solder residue is non‐corrosive and so minimal that it does not require a post‐solder cleaning operation. The solder joints exhibit good wetting, excellent joint strength and are essentially void‐free. Assembled circuits processed in this way meet all the criteria for ionic cleanliness and surface insulation resistance without post‐solder cleaning.

The use of nitrogen‐based soldering environments, rather than ambient air, has been widely promoted for both reflow and machine soldering. Earlier claims of process improvements derived mainly from the enhancement of process windows related to improved solderability. The improvements seem to be accepted in the industry but may not be very significant except when accompanying other changes in production soldering facilitated by the use of inert environments. Appropriate process changes include the use of finer pitch devices and more densely populated boards and changes in cleaning technology or the use of no‐clean processes. Material changes include the increased use of new technology for both pastes and fluxes (generally no‐clean), increased use of high temperature solder alloys and the possible need to use lead‐free alloys for environmental reasons. This paper discusses the relationship between atmosphere effects on soldering processes, and process and material changes which favour soldering in atmospheres other than air. It presents some recent data on improvements to soldering resulting from the use of nitrogen environments.

The purpose of this paper is to examine the impact of three-dimensional (3D)-printing process settings (particularly print orientation) on the tribological properties of different polymers.

In this study, fused deposition modelling 3D-printing technology was used for fabricating the specimens. To evaluate the influence of print orientation, the test pieces were manufactured horizontally (X) and vertically (Z). The tribological properties of various printed polymers, which are polylactide acid, high tensile/high temperature-polylactide acid and polyethylene terephthalate-glycol have been studied. The tribological tests have been carried out under reciprocating sliding and dry condition.

The results show that the presence of various orientations during the 3D-printing process makes a difference in the coefficient of friction and the wear depth values. Findings suggest that printing structure in the horizontal orientation (X) assists in reducing friction and wear.

To date, there has been very limited research on the tribology of objects produced by 3D printing. This work was made as an attempt to pave the way for future research on the science of tribology of 3D-printed polymers.

The evaluation of novel materials such as the acrylonitrile styrene acrylate (ASA) for tribological and mechanical conditions can provide a structural protection against the environmental and wear effects that results in the long-term integrity of the 3 D printed parts. Results of the experimental stage are intended to identify the influence of the printing conditions on the functional characteristics of ASA parts that results in variations of the friction coefficient, wear rate and tensile response. In addition, this study aims to highlight the relevance of printing parameters to avoid the use of chemical post-processing stages, increasing the performance and sustainability of the process.

In this research, an evaluation of the influence of printing parameters of layer thickness and temperature on the mechanical and tribological response have been carried out for ASA specimens manufactured by fused filament fabrication technology. For this purpose, a range of three different values of thickness of fused layer and three different printing temperatures were combined in the manufacturing process of tests samples. Mechanical behavior of the printed parts was evaluated by standard tensile tests, and friction forces were measured by pin-on-disk tribological tests against steel spheres.

Higher layer thickness of the printed parts shows lower resistance to tribological wear effects; in terms of friction coefficient and wear rate, this type of parts also presents lower tensile strength. It has been detected that mechanical and tribological behavior is highly related to the micro-geometrical characteristics of the printed surfaces, which can be controlled by the manufacturing parameters. Under this consideration, a reduction in the coefficient of friction near to 65% in the average value was obtained through the variation of the layer thickness of printed surfaces.

This research aims to fill a gap in the scientific literature about the use of specific additive manufacturing materials under dynamic contact. This paper is mainly focused on the influence of the manufacturing parameters on the tribological and mechanical behavior of a weather resistant polymer (ASA).

Python codes are developed for the versatile structural analysis on a 3 spar multi-cell box beam by means of idealization approach.

Shear flow distribution, stiffener loads, location of shear center and location of geometric center are computed via numpy module. Data visualization is performed by using Matplotlib module.

Python scripts are developed for the structural analysis of multi-cell box beams in lieu of long hand solutions. In-house developed python codes are made available to be used with finite element analysis for verification purposes.

The use of python scripts for the structural analysis provides prompt visualization, especially once dimensional variations are concerned in the frame of aircraft structural design. The developed python scripts would serve as a practical tool that is widely applicable to various multi-cell wing boxes for stiffness purposes. This would be further extended to the structural integrity problems to cover the effect of gaps and/or cut-outs in shear flow distribution in box-beams.