Search results

This paper outlines the composition of water soluble fluxes for the electronics industry and their methods of use when wave soldering and reflowing tinned coatings and solder pastes. Process optimisation is facilitated by the Taguchi method. Three types of cleaning machinery are evoked, with varying results. It is shown that the energy/time relationship is important to ensure adequate cleaning quality. A number of fallacious arguments are debunked. Methods of water purification and the problems of effluent treatment for all sizes of installation are addressed. Doubt is expressed as to the viability of closed‐circuit water recycling except for the largest installations or where exceptional conditions prevail. It is shown that water soluble fluxes and their subsequent aqueous removal are unlikely to make any significant contribution to the Greenhouse Effect. The overall cost of their use is substantially similar to that of rosin fluxes with CFC‐113 azeotropes at 1986 prices. Cleanliness control under production and laboratory conditions is discussed with reference to both ionic contamination testing, including its use for SMDs, and SIR analysis, especially at low voltages, including non‐destructive production SIR testing. Reliability of the assembled circuits is shown to be at least as good as that with more traditional soldering and cleaning methods, frequently better, and this is the case even for military and aerospace applications. The paper concludes that, now that quality water soluble solder pastes are available, this method is most likely to become the workhorse for the majority of electronics applications.

Non‐destructive testing (NDT) makes use of the controlled application of physical phenomena to materials so that interpretation of signals derived from the materials indicates their fitness, or otherwise, to perform a design function. The purpose of NDT is to ensure that mainly load carrying components and structures are free from defects. Established non‐destructive testing has become of primary importance in aircraft maintenance and manufacture both as a positive indication for safety and as a method of saving costs. This article written for aircraft engineers is a broad review of the development of NDT in their industry and a brief indication of the status of its various components today.

This paper aims to present a methodology for the detection and categorisation of metal powder particles that are partially attached to additively manufactured lattice structures. It proposes a software algorithm to process micro computed tomography (µCT) image data, thereby providing a systematic and formal basis for the design and certification of powder bed fusion lattice structures, as is required for the certification of medical implants.

This paper details the design and development of a software algorithm for the analysis of µCT image data. The algorithm was designed to allow statistical probability of results based on key independent variables. Three data sets with a single unique parameter were input through the algorithm to allow for characterisation and analysis of like data sets.

This paper demonstrates the application of the proposed algorithm with three data sets, presenting a detailed visual rendering derived from the input image data, with the partially attached particles highlighted. Histograms for various geometric attributes are output, and a continuous trend between the three different data sets is highlighted based on the single unique parameter.

This paper presents a novel methodology for non-destructive algorithmic detection and categorisation of partially attached metal powder particles, of which no formal methods exist. This material is available to download as a part of a provided GitHub repository.

The aim of this research is to design a wall climbing robot (WCR) for the non‐destructive inspection (NDT) of the above‐ground storage tanks (ASTs) autonomously making the industrial inspection and maintenance tasks safer.

A WCR is designed that can be equipped with any NDT sensor. It uses permanent magnets as an adhesion mechanism to crawl over the steel tank walls. A surface coverage algorithm is proposed for the WCR to scan the AST wall surfaces autonomously with the NDT sensors to perform the necessary inspection tasks.

The proposed surface coverage algorithm performs the complete coverage of the AST walls under different obstacle configurations. It has been tested and demonstrated in simulations.

A surface coverage algorithm is proposed for the WCR to perform the non‐destructive inspection of the ASTs autonomously. It can also be used in applications like cleaning glass building and painting ship hulls, etc.

To present an entirely new technology to be used in the in‐service inspection of storage tanks for hazardous products in several different industries.

Current interior storage oil tank plate inspection is a very expensive and time‐consuming task. The related tasks involve high cost, several hazards to environment and the operators involved in the cleaning jobs. Several research areas were investigated during the development of this tool, fundamentally robotics and non‐destructive test tools. Initial trials in laboratory were complemented with a field test program in near‐real conditions.

A new design of tool for in‐service inspection of such equipments proved to be feasible to be constructed and operated and in accordance with current safety regulations.

New robotics application in non‐destructive testing methodologies for application in in‐service storage equipments. The internal conditions possible to find in the interior of a storage tank, like fixtures, properties of the stored products (inflammable and aggressive), sludge and sand on the bottom, no ambient light, etc., are significant challenges to the development of such a tool.

Developed a robotized tool for inspection of the floor and walls of in‐service tanks, in order to allow an evaluation of the condition of the plates of these tanks, avoiding the long period, hazards and high costs necessary for creating the conditions for reality out of service inspection.

The novelty of the RobTank Inspec project could be evaluated from the two or three existing competitors in the world, and the results of the surveys undertaken.

Surface insulation resistance (SIR) testing is mainly used as a qualification procedure to determine the ‘best’ combination of materials and processes for a given application. The usual tests are destructive and last generally from ten to 56 days, 28 days being very common. It is clear that such tests are unsuitable for production quality control. With cleaned boards, ionic contamination testing is current and is specified in many standards. Even so, the presence of non‐ionic hygroscopic contaminants, such as residues from many fluxes and solder pastes, remains undetected. Their presence may cause functional failures, especially if there is some ionic contamination, even within acceptable limits, as well. When using ‘no‐clean’ fluxes and pastes, ionic contamination testing is sometimes used to determine whether a process is constant, although it may be extremely difficult or even impossible to interpret the results into a function of reliability. SIR testing is the only easy way of forecasting a loss of reliability. A method is described of non‐destructive SIR testing in a few hours and correlating the results to reliability as determined by long‐term qualification testing. This method is valid for PCB assemblies which have or have not been cleaned.

The paper aims to provide a review of the uses of robots in non‐destructive testing (NDT).

Following a brief introduction, this paper considers the uses of robotic NDT, with an emphasis on applications in certain key industries. While some development activities are considered, the emphasis is on existing systems rather than research and reference is made to a selection of commercial products.

It is shown that robotic NDT finds limited uses in most of the industries using conventional NDT methodologies. These include oil and gas, offshore and shipping, petrochemicals, aerospace and power generation. In some instances, financial benefits arise from their use while in other cases the use reflects access difficulties or the hazards associated with testing.

Applications in the nuclear power industry is not considered but will be covered in a subsequent article. Remotely operated vehicles, which are not considered to be true robots, are also excluded.

This paper provides details of NDT robots and their uses in a selection of key industries.

This paper aims to report a case study regarding the combined use of several non‐destructive techniques (NDTs) as a tool in the management of diagnosis and refurbishment of a damaged reinforced concrete building.

Four types of NDTs have been selected and carried out on the pillars of the building: visual inspection, electromagnetic rebar location, sonic test and rebound hammer test. The campaign has been planned and run in order to get the highest amount of reliable data about materials degradation and structural safety with limited costs and limited interference with the functionality of the building.

The diagnostic campaign highlighted the usefulness of the selected techniques in the diagnosis of the type and the amount of degradation, thus permitting a plan of refurbishments to be defined, and to get a realistic estimation of restoration costs.

NDTs' ability to specifically identify a type of damage may be viewed as a reliable tool in assessing and managing the structural life‐cycle cost.

The presented case study highlighted that NDTs are very likely to locate and quantify the damage of materials and buildings, so that they can be considered as one of the most important parts of health monitoring of civil structures and infrastructures.