In-plant real-time manufacturing water content characterisation

To trial the concept of in-plant real-time manufacturing water content characterisation, a commercial optical system for measuring light absorption and backscatter intensity was used with samples of food industry wastewater, and the results compared with conventional laboratory based water analysis. It is shown that the instrumentation is capable of coping with the range of turbidities presented by the wastewater and that there is some correlation between the absorption and backscatter measurements with the conventional parameters COD and TSS. It is suggested that combining backscatter and absorption data may provide an optical fingerprint of effluent that can be used as a management parameter, for example to identify unexpected contamination events. Potential uses of the instrumentation are discussed, including to provide rapid feedback on effects of system changes on effluent production, and in a feedback control loop to allow reuse of water without compromising product safety

A concept of water usage efficiency to support water reduction in manufacturing industry

Increasing pressures on freshwater supplies, continuity of supply uncertainties, and costs linked to legislative compliance, such as for wastewater treatment, are driving water use reduction up the agenda of manufacturing businesses. A survey is presented of current analysis methods and tools generally available to industry to analyze environmental impact of, and to manage, water use. These include life cycle analysis, water footprinting, strategic planning, water auditing, and process integration. It is identified that the methods surveyed do not provide insight into the operational requirements from individual process steps for water, instead taking such requirements as a given. We argue that such understanding is required for a proactive approach to long-term water usage reduction, in which sustainability is taken into account at the design stage for both process and product. As a first step to achieving this, we propose a concept of water usage efficiency which can be used to evaluate current and proposed processes and products. Three measures of efficiency are defined, supported by a framework of a detailed categorization and representation of water flows within a production system. The calculation of the efficiency measures is illustrated using the example of a tomato sauce production line. Finally, the elements required to create a useable tool based on the efficiency measures are discussed

Epoxy adhesive behaviour on ceramic surfaces in commercial optoelectronic assemblies

Chemical and physical variability in the as-received state of aluminium oxide and aluminium nitride ceramic substrate materials used in optoelectronic modules currently leads to a process yield less than 100% when adhesives are used for assembly and interconnection. The phenomenon of epoxy bleed is a contributing factor to this yield and steps are not yet taken in the industry to control or inhibit the undesirable wetting. Standard surface texture measurement techniques, XPS and contact angle measurements were implemented to characterise and compare commercial as-received samples. The quality controls currently in place are assessed and additional analysis methods in the QC stage are suggested for increasing yield. Commercially available conductive and thermally conductive adhesives, also used in optoelectronic module manufacture, were studied along with the surfaces

A substrateless process for sustainable manufacture of electronic assemblies

The exponential growth in worldwide production and consumption of electronics, and the short operational lifespan of many products, has resulted in increasing amounts of electronics waste. There is enormous pressure on electronic product manufacturers to reduce the consumption of materials and their subsequent impact on the environment, especially at the end-of-life, through such measures as the EU Directive on Waste Electrical and Electronic Equipment (WEEE). Ideally any product should be separable into its constituent parts at end of life for subsequent reuse, recycling or disposal. However separation of a typical electronic assembly into its constituent parts is problematic because of the intimate nature of the bonding between the glass fibre/thermoset composite laminate, the laminated and embedded copper conductor layers and the soldered electronic components. To address these problems, an alternative processing route for manufacture of electronics assemblies is proposed, in which the electronic components and metal content can be easily separated out from the organic content at end-of-life. No separate printed circuit board is used to interconnect the components so the process may be termed as “substrateless”. The route has the additional advantage that standard electronic assembly equipment can be used. In this work the process route is described and the implications of adoption for the electronics manufacturing industry considered. The results of initial proof of principle trials are described, and conclusions are drawn as to the development work required to allow adoption of the process by the industry

The UK electronics manufacturing industry 1997-2003: a case study of the effect of globalization

Statistical data and information from industry interviews are used to build a picture of the implications of, and responses to, globalization in the key industry of electronics contract manufacturing in the UK. A comprehensive list of companies in the sector with associated employment and turnover data has been created from a variety of sources. Comparison of 2003 data with a 1997 dataset produces a unique longitudinal statistical picture of the industry over a period marked by the increasing influence of globalization. Total employment in the industry has decreased by 39 per cent from approximately 37 600 to 23 100 between 1997 and 2003. This breaks down into a decline in the printed circuit board (PCB) manufacturing subsector of 61 per cent, from 16 300 to around 6400, and a much smaller decline in the printed circuit board sub-contract assembly (PCBA) subsector of 22 per cent, from approximately 21400 to 16700. There has been a major shift in employment distribution away from large companies. Interview results indicate that the loss of large company capacity may have strategic implications for future technological capability. However, the UK is seen as a source of innovation and retention of strong engineering skills is key to bringing new products to the market

Assessment of the capability of an optical sensor for in-line real-time wastewater quality analysis in food manufacturing

This work investigates the use of a commercial optical product monitor to achieve in-line real-time water content analysis. Test fluids were used and optical measurements of attenuation of light intensity at four colours were made. These measurements were used to identify any relationship between these and the water quality parameters of turbidity and colour. Variation in light attenuation for turbidities up to 1700 NTU was successfully resolved by the instrument, with optical data for turbidities ≥ 20 NTU fitting well the Beer-Lambert model. The sensor was also able to clearly identify the effect of filtering out suspended solids with unfiltered samples (apparent colour) exhibiting significantly higher attenuation coefficients than filtered samples (true colour). Further studies will concentrate on whether the instrument can analyse samples with turbidities higher than 1700 NTU, together with further investigating the variation in the attenuation coefficient seen with turbidity and colour of light

Adhesion of precision welded lead-free electrical interconnects formed by molten droplet deposition

An existing process, droplet welding, has been proposed for the production of precision, high-temperature, lead-free electrical joints. A modified metal inert gas (MIG) welding plasma is used to produce molten metal droplets, which then fall on a part to make an electrical joint. The subject of the present paper is an investigation of the factors affecting successful welded joint formation for a given droplet material and target, with the goal of providing the basis of a computer model to enable rapid process set-up on a production line. It is found that a parameter space can be identified for good adhesion of a droplet to a target, characterized by droplet temperature and target thickness, for each droplet material/target material combination. Essentially adhesion can be viewed as determined by competition between the delivery of thermal energy from the droplet to the target immediately underneath the droplet, and the removal of the energy from the interface region to the rest of the target, with no role played by the droplet kinetics after impact. It is therefore concluded that a relatively simple thermal model could be used by production-line engineers to identify the parameter space for rapid process set-up with new material combinations and products. The conclusion is supported by evidence from high-speed video images of droplet impact. Such a simple thermal model is proposed and is found to be capable of predicting adhesion between droplet and target. The results are discussed in the context of the extensive literature on molten droplet impact and solidification

Packaging of microfluidic devices for fluid interconnection using thermoplastics

A new packaging method for microfluidic devices is proposed of polymer over-molding to form a fluidic manifold integrated with the device in a single step. The anticipated advantages of the proposed method of packaging are ease of assembly and low part count, making it suitable for low cost and high volume manufacturing. This paper reports the results of a preliminary investigation into this concept. Glass and silicon inserts of 25 times 20 mm in size, used to represent microfluidic devices, were over-molded in an injection molding process with a range of polymers. The inserts were found to survive the molding process intact. The adhesion between overmold and insert was investigated by subjecting the interface between the overmold and insert surface to a hydrostatic pressure of up to 100 lbf/in2 (6.9 bar). The durability of the interfacial adhesion to hydrolysis was investigated by immersion in water at 50degC for 24 h before testing. Direct measurements of adhesion strength between polymer and glass were also attempted by tensile tests on lap-jointed samples. The best and most durable adhesion for glass and silicon inserts was found for polyamide (PA) 12, which is a low hygroscopicity PA. The ranking of polymers by their performances in the pressurization tests was consistent with the ranking by the calculated work-of-adhesion values for polymer/glass and polymer/silicon joints

The assessment of areal surface texture parameters for characterizing the adhesive bond strength of copper plated micro-machined glass.

The micro-electronics industry is investigating glass as an alternative printed circuit board material and interposer. Electroless copper plating of glass is required for tracks and interconnects, but understanding of how the surface topography of the glass substrate affects the mechanics of the copper/glass bond quality is limited. Areal surface texture parameters provide the potential for characterizing key surface features associated with improving copper/glass bonding. Laser ablation techniques have been used to prepare glass surfaces with micro-scale structured features, and these features have been quantified using areal parameters. The copper/glass bond strength has been quantified using scratch testing techniques, with statistical analysis identifying strongly correlating areal parameters that may be used for predictive design of glass surfaces

Productionisation issues for commercialisation of microfluidic based devices

Purpose Microfluidic or “lab-on-a-chip” technology is seen as a key enabler in the rapidly expanding market for medical point-of-care (POC) and other kinds of portable diagnostic device. In this paper we discuss two proposed packaging processes for large scale manufacture of microfluidic systems. Design/methodology/approach In the first packaging process, polymer overmoulding of a microfluidic chip is used to form a fluidic manifold integrated with the device in a single step. The anticipated advantages of the proposed method of packaging are ease of assembly and low part count. The second process involves the use of low frequency induction heating (LFIH) for the sealing of polymer microfluidics. The method requires no chamber, and provides fast and selective heating to the interface to be joined. Findings Initial work with glass microfluidics has demonstrated feasibility for overmoulding through two separate sealing principles. One is using the overmould as a physical support structure and providing sealing using a compliant ferrule. The other relies on adhesion between the material of the overmould and the microfluidic device to provide a seal. As regards LFIH work on selection and structuring of susceptor materials is reported, together with analysis of the dimensions of the heat affected zone. Acrylic plates have been joined using a thin (<10 μm) nickel susceptor providing a fluid seal that withstood a pressure of 590kPa. Originality/value Microfluidic chips have until now been produced in relatively small numbers. To scale-up from laboratory systems to the production volumes required for mass markets, packaging methods need to be adapted to mass manufacture