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This paper aims to demonstrate the practicability of the liquid metal printer, developed in the authors’ laboratory, in the direct manufacture and assembly of circuit boards at the end customer side using GaIn24.5 alloy as printing ink at room temperature.

A practical procedure for printing a real designed frequency modulation (FM) radio circuit on flexible and transparent substrate using liquid metal printer was established. Necessary electronic components are then assembled on this circuit board. To enhance the mechanical stability of the FM radio circuit board, we further package the circuit board using room temperature vulcanizing silicone rubber. Finally, an efficient way to recycle the liquid metal ink and electronic components is presented at the end of circuit board’s life cycle.

Methods of designing the circuit patterns that are applicable to liquid metal printer are similar to the conventional printed circuit board (PCB) designing strategies. The procedure of applying liquid metal printer for printing the circuits is entirely automatic, cost-effective and highly time-saving, which allows the user to print out desired device in a moment. Through appropriate packaging, the FM radio circuit board can be flexibly used. These PCBs own many outstanding merits including easy modification and stretchability. Nearly all liquid metal ink and components can be recycled.

The present end-customer-oriented liquid metal printing opens the way for large-scale personal electronics manufacture which is expected to initiate many emerging applications in education, design, industry, entertainment and more maker targets.

In the past 15 years stretchable electronic circuits have emerged as a new technology in the domain of assembly, interconnections and sensor circuits and assembly technologies. In the meantime a wide variety of processes with the use of many different materials have been explored in this new field. The purpose of the current contribution is for the authors to present an approach for stretchable circuits which is inspired by conventional rigid and flexible printed circuit board (PCB) technology. Two variants of this technology are presented: stretchable circuit board (SCB) and stretchable mould interconnect (SMI).

Similarly as in PCB 17 or 35 μm thick sheets of electrodeposited or rolled‐annealed Cu are structured to form the conductive tracks, and off‐the‐shelf, standard packaged, rigid components are assembled on the Cu contact pads using lead‐free solder materials and reflow processes. Stretchability is obtained by shaping the Cu tracks not as straight lines, like in normal PCB design, but as horseshoe shaped meanders. Instead of rigid or flexible board materials, elastic materials, predominantly PDMS (polydimethylsiloxane), are used to embed the conductors and the components, thus serving as circuit carrier. The authors include some mechanical modeling and design considerations, aimed at the optimization of the build‐up and combination of elastic, flexible and rigid materials towards minimal stress and maximum mechanical reliability in the structures. Furthermore, details on the two production processes are given, reliability findings are summarised, and a number of functional demonstrators, realized with the technologies, are described.

Key conclusions of the work are that: supporting the metal meanders with a flexible carrier prior to embedding in an elastic substrate substantially increases the reliability under mechanical stress (cyclic uniaxial stretching) of the stretchable interconnect and the transition areas between rigid components and stretchable interconnects are the zones which are most sensitive to failure under mechanical stress. Careful design and technology implementation is necessary, providing a gradual transition from rigid to flexible to stretchable parts of the circuit.

Technologies for stretchable circuits, with the same level of similarity to standard PCB manufacturing and assembly, and thus with the same high potential for transfer to an industrial environment and for mass production, have not been shown before.

To present and discuss open trace defects uncovered in an FR4 assembly during electrical testing.

This paper presents open trace defects observed in FR4 assemblies and analyses the distribution of defects. The paper also discusses possible root causes for their occurrence.

The open trace defects that occurred during printed circuit board (PCB) fabrication should have been observed by the board manufacturer. It appears that the PCB manufacturer did not perform automatic optical inspection (AOI) and electrical testing during the manufacturing of the boards. The cost due to the rejected PCBAs was approximately 3x times that of the PCB cost.

The paper highlights the costly impact of uncovering a PCB defect after assembly. Based on the results of this study, the implementation of electrical testing and AOI for PCBs is recommended.

To determine the optimal chip/component placement for multi‐chip module (MCM) and printed circuit board (PCB) under thermal constraint.

The placement of power dissipating chips/component is carried out using genetic algorithms (GA) in order to achieve uniform thermal distribution on MCM and PCB. The thermal distribution on the MCM and PCB are predicted using 2D‐finite element method (FEM) analysis. Different number of chip/component and FEM meshing size is used to investigate the placement of chips/components.

The optimal placement of chip/component using GA is compared well to other placement techniques. The coarse meshing for FEM employed here is found adequate to carry out optimal placement of components by GA.

The analysis is valid for constant properties of MCM or PCB and steady state conditions. The chip/component size is limited to a single standard size.

The method is very useful for practical design of chip/component placement on MCM/PCB under thermal consideration.

FEM analyses of MCM and PCB can be easily implemented in the optimization procedure for obtaining the optimal chip/component placement based on thermal constraints.

To review opportunities for use of digital printing in the printed circuit board (PCB) industry and to introduce background to ink jet printing, process development and applications in order to reduce costs, enhance efficiency and to enable PCB producers to operate in a more sustainable and flexible manner.

This paper has been written to provide a review of ink jet printing applications in the PCB industry. Ink jet print technology background, ink development and the processes made possible by ink and print head improvements have been described together with a description of the benefits available through digital printing.

It was found that there have been significant developments over recent years in both hardware technology (print heads and accurate print platforms) as well as improvements in the design of inks both for ink jet print performance and functional characteristics. These improvements have been integrated to provide an exciting new technology which can be applied in the manufacture of PCBs to reduce manufacturing costs and increase flexibility of manufacture.

The value of the paper lies in its ability to provide information on the scope of opportunities for ink jet printing in the PCB manufacturing process through the use of a range of new inks having specific properties. The design and development of highly accurate machinery provides the opportunity to attain the desired print resolution.

This paper aims to develop an estimation tool for warpage behavior of slim printed circuit board (PCB) array while soldering with electronic components by using finite element method. One of the essential requirements for handheld devices, such as smart phone, digital camera, and Note-PC, is the slim design to satisfy the customers’ desires. Accordingly, the printed circuit board (PCB) should be also thinner for a slim appearance, which would result in decreasing the PCB’s bending stiffness. This means that PCB deforms severely during the reflow (soldering) process where the peak temperature goes up to 250°C. Therefore, it is important to estimate PCB deformation at a high temperature for thermo-mechanical quality/reliability after reflow process.

A numerical simulation technique was devised and customized to accurately estimate the behavior of a thin printed board assembly (PBA) during reflow by considering all components, including PCB, microelectronic packages and solder interconnects.

By applying appropriate constraints and boundary conditions, it was found that PBA’s warpage can be accurately predicted during the reflow process. The results were also validated by warpage measurement, which showed a fairly good agreement with one and another.

For research limitations, there are many assumptions regarding numerical modeling. That is, the viscoplastic material property of solder ball is ignored, the reflow profile is simplified and the accurate heat capacity is not considered. Furthermore, the residual stress within the PCB, generated at PCB manufacturing process, is not included in this paper.

This paper shows how to calculate PBA warpage during the reflow process as accurately as possible. This methodology helps a PCB designer and surface-mount technology (SMT) process manager to predict a PBA warpage issue and modify PCB design before PCB real fabrication. Practically, this modeling and simulation process can be easily performed by using a graphical user interface (GUI) module, so that the engineer can handle an issue by inputting some numbers and clicking some buttons.

In a common sense manner, a numerical simulation method can decrease time and cost in manufacturing real samples. This PCB warpage method can also decrease product development duration and produce a new product earlier. Furthermore, PCB is a common component in all the electronic devices. So, this PCB warpage method can have various applications.

Because of an economic advantage, the development of a numerical simulation tool for estimating the thin PBA warpage behaviour during reflow process was attempted. The developed tool contains the features of detailed modeling for electronic components and contact boundary conditions of the supporting rails in the reflow oven.

The purpose of this paper is to form copper coin-embedded printed circuit board (PCB) for high heat dissipation.

Manufacturing optimization of copper coin-embedded PCB involved in the design and treatment of copper coin, resin flush removal and flatness control. Thermal simulation was used to investigate the effect of copper coin on heat dissipation of PCB products. Lead-free reflow soldering and thrust tests were used to characterize the reliable performance of copper coin-embedded PCB.

The copper coin-embedded PCB had good agreement with resin flush removal and flatness control. Thermal simulation results indicated that copper coin could significantly enhance the heat-dissipation rate by means of a direct contact with the high-power integrated circuit chip. The copper coin-embedded PCB exhibited a reliable structure capable of withstanding high-temperature reflow soldering and high thrust testing.

The use of a copper coin-embedded PCB could lead to higher heat dissipation for the stable performance of high-power electronic components. The copper coin-embedded method could have important potential for improving the design for heat dissipation in the PCB industry.

PMD have appointed David H. Ormerod to the position of printed circuits products manager as part of their marketing organisation.

A product's design influences its manufacturing process and the associated costs. Consequently, design engineers need to review their designs from a manufacturing perspective. While ‘Design For Manufacturing’ (DFM) tools often identify the manufacturing problems associated with a design, they would be more effective if these problems could be represented to the designer in terms of a cost value. This research developed a cost estimation tool for the designer in the surface mount printed circuit board (PCB) domain by integrating computer aided design, computer aided process planning (CAPP) and cost estimation techniques using a knowledge based framework. The cost estimation can be done in two design stages. First, an initial approximation of the manufacturing cost can be obtained using information such as the component mix, type of substrate and the size of board. After the detailed design of the PCB has been developed, a more accurate PCB assembly cost can be obtained using computer aided design (CAD) data. Both cost determination strategies would require the generation of a macro‐process plan. The cost advisor considers tangible and intangible factors. This cost advisor and the DFM environment have been developed using C ++ and object oriented programming constructs under the MS Windows operating system.

W. Canning Materials Ltd have announced the appointment of Mr W. E. I. Galloway as Managing Director with effect from 1st January, 1985. The Company is a leading manufacturer and supplier of industrial and speciality chemicals for the surface finishing industry.