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Article
Publication date: 3 April 2017

József Hlinka, Miklós Berczeli, Gábor Buza and Zoltán Weltsch

This paper aims to discuss the effect of surface treatment on the wettability between copper and a lead-free solder paste. The industrial applications of laser technologies are…

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Abstract

Purpose

This paper aims to discuss the effect of surface treatment on the wettability between copper and a lead-free solder paste. The industrial applications of laser technologies are increasing constantly. A specific laser treatment can modify the surface energy of copper and affect the wetting properties.

Design/methodology/approach

The surfaces of copper plates were treated using an Nd:YAG laser with varying laser powers. After laser surface treatment, wetting experiments were performed between the copper plates and SAC305 lead-free solder paste. The effect of laser treatment on copper surface was analysed using optical microscopy and scanning electron microscopy (SEM).

Findings

The experimental results showed that the wetting contact angles changed with the variation in laser power. Furthermore, it means that the surface energy of copper plates was changed by the laser treatment. The results demonstrated that the contact angles also changed when a different soldering paste was used.

Originality/value

Previous laser surface treatment can be a possible way to optimize the wettability between solders and substrates and to increase the quality of the soldered joints.

Details

Soldering & Surface Mount Technology, vol. 29 no. 2
Type: Research Article
ISSN: 0954-0911

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Article
Publication date: 31 October 2018

Jozsef Rohacs, Istvan Jankovics and Daniel Rohacs

The purpose of this paper is to overview the systems and their elements developing for supporting the less-skilled pi-lots.

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Abstract

Purpose

The purpose of this paper is to overview the systems and their elements developing for supporting the less-skilled pi-lots.

Design/methodology/approach

Several European (like EPATS, SAT-Rdmp, Pplane, Esposa, Clean Sky2) and national projects (NASA SATS, Hungarian SafeFly) develop the personal/small aircraft and personal/small aircraft transportation systems. The projects had analysed the safety aspects, too, and they underlined the aircraft will be controlled by so-called less-skilled pilots (owners, renters), having less experiences. The paper defines the cross-connected controls, introduces the methods of subjective analysis in pilot decision processes, improves the pilot workload model, defines the possible workload management and describes the developing pilot decision support system.

Findings

Analysing the personal/small aircraft safety aspects, a unique and important safety problem induced by less-skilled pilots has been identified. The considerable simplification of the air-craft control system, supporting the pilot subjective decisions and introducing the pilot work-load management, may eliminate this problem.

Research limitations/implications

Only the system elements have been used in concept validation tests.

Practical implications

The developing pilot supporting system in its general form has on - board and ground sub-systems, too, except a series of elements integrated into the pilot cockpit environment and control system. Several system elements (sensors, integrated controls, etc.) might be implement now, but the total system need further studies. The subjective decision process needs further development of the methodology and concept validation.

Social implications

The system may catalyse the society acceptance of the personal aircraft and their safer piloting, applicability.

Originality/value

The paper introduces an original supporting system for less-skilled pilots.

Details

Aircraft Engineering and Aerospace Technology, vol. 91 no. 5
Type: Research Article
ISSN: 1748-8842

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