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This paper aims to introduce a new indicative parameter of filling efficiency to quantify the performance and productivity of the flip-chip underfill encapsulation process. Additionally, the variation effect of the bump pitch of flip-chip on the filling efficiency was demonstrated to provide insight for flip-chip design optimization.

The filling efficiency was formulated analytically based on the conceptual spatial and temporal perspectives. Subsequently, the effect of bump pitch on filling efficiency was studied based on the past actual-scaled and current scaled-up underfill experiments. The latter scaled-up experiment was validated with both the finite volume method-based numerical simulation and analytical filling time model. Moreover, the scaling validity of scaled-up experiment was justified based on the similarity analysis of dimensionless number.

Through the scaling analysis, the current scaled-up experimental system is justified to be valid since the adopted scaling factor 40 is less than the theoretical scaling limit of 270. Furthermore, the current experiment was qualitatively well validated with the numerical simulation and analytical filling time model. It is found that the filling efficiency increases with the bump pitch, such that doubling the bump pitch would triple the efficiency.

The new performance indicative index of filling efficiency enables the package designers to justify the variation effect of underfill parameter on the overall underfill process. Moreover, the upper limit of scaling factor for scaled-up package was derived to serve as the guideline for future scaled-up underfill experiments.

The performance of underfill process as highlighted in this paper was never being quantified before in the past literatures. Similarly, the scaling limit that is associated to the scaled-up underfill experiment was never being reported elsewhere too.

This paper aims to determine the optimum set of temperatures through correlation study to attain the most effective capillary flow of underfill in a multi-stack ball grid array (BGA) chip device.

Finite volume method is implemented in the simulation. A three-layer multi-stack BGA is modeled to simulate the underfill flow. The simulated models were well validated with the previous experimental work on underfill process.

The completion filling time shows high regression R-squared value of up to 0.9918, which indicates a substantial acceleration on the underfill process because of incorporation of thermal delta. An introduction of 11 °C thermal delta to the multi-stacks BGA managed to reduce the filling time by up to 16.4%.

Temperature-induced capillary flow is a relatively new type of driven underfill designed specifically for package on package BGA components. Its simple implementation can further improve the productivity of existing underfill process in the industry that is desirable in reducing the process lead time.

The effect of temperature-induced capillary flow in underfill encapsulation on multi-stacks BGA by means of statistical correlation study is a relatively new topic, which has never been reported in any other research according to the authors’ knowledge.

The purpose of this paper is to present a new powder‐based solid freeforming method based on conventional furnace sintering after co‐deposition of mould and part powder materials.

Based on acoustic powder deposition, both mould and part powder materials are delivered simultaneously into the forming area according to the cross section of the 3D computer file. The part is formed in the form of loose powder surrounded by the mould powder again in a loose state. The whole assembly can then be sintered by a conventional method and the mould powder, which has a higher sintering temperature than that of part powder, remains in the loose state after sintering and can be removed.

Complex‐shaped components containing re‐entrant cavities and the capability of being made with 3D functional gradients can be rendered directly as a powder preform suitable for subsequent compaction or direct sintering in a conventional furnace. The flowability and compatibility of the powders need to be selected carefully and the track distance between part/mould powders is important for forming a vertical wall.

The main factors affecting building from powder tracks are identified, including the effect of track distance at an interface on integrity, discontinuous feeding on bends and the effects of fill strategies. The flow rates of the part and mould powder as well as their geometrical maps are controlled computationally. Materials and instrumental aspects are discussed.

This paper describes a method to produce complex‐shaped object without residual stress and expensive lasers and the process could be modified to include 3D functional gradients.

This paper aims to study the filling progression of underfill flow and void formation during the flip-chip encapsulation process.

A new parameter of filling progression that relates volume fraction filled to filling displacement was formulated analytically. Another indicative parameter of filling efficiency was also introduced to quantify the voiding fraction in filling progression. Additionally, the underfill process on different flip-chips based on the past experiments was numerically simulated.

All findings were well-validated with reference to the past experimental results, in terms of quantitative filling progression and qualitative flow profiles. The volume fraction filled increases monotonically with the filling displacement and thus the filling time. As the underfill fluid advances, the size of the void decreases while the filling efficiency increases. Furthermore, the void formed during the underfilling flow stage was caused by the accelerated contact line jump at the bump entrance.

The filling progression enabled manufacturers to forecast the underfill flow front, as it advances through the flip-chip. Moreover, filling progression and filling efficiency could provide quantitative insights for the determination of void formations at any filling stages. The voiding formation mechanism enables the prompt formulation of countermeasures.

Both the filling progression and filling efficiency are new indicative parameters in quantifying the performance of the filling process while considering the reliability defects such as incomplete filling and voiding.

This study aims to propose and evaluate the progress in the basic-pixel (a strategy to generate continuous trajectories that fill out the entire surface) algorithm towards performance gain. The objective is also to investigate the operational efficiency and effectiveness of an enhanced version compared with conventional strategies.

For the first objective, the proposed methodology is to apply the improvements proposed in the basic-pixel strategy, test it on three demonstrative parts and statistically evaluate the performance using the distance trajectory criterion. For the second objective, the enhanced-pixel strategy is compared with conventional strategies in terms of trajectory distance, build time and the number of arcs starts and stops (operational efficiency) and targeting the nominal geometry of a part (operational effectiveness).

The results showed that the improvements proposed to the basic-pixel strategy could generate continuous trajectories with shorter distances and comparable building times (operational efficiency). Regarding operational effectiveness, the parts built by the enhanced-pixel strategy presented lower dimensional deviation than the other strategies studied. Therefore, the enhanced-pixel strategy appears to be a good candidate for building more complex printable parts and delivering operational efficiency and effectiveness.

This paper presents an evolution of the basic-pixel strategy (a space-filling strategy) with the introduction of new elements in the algorithm and proves the improvement of the strategy’s performance with this. An interesting comparison is also presented in terms of operational efficiency and effectiveness between the enhanced-pixel strategy and conventional strategies.

The purpose of this paper is to suggest an analysis methodology for the stencil printing process and to obtain proper design parameters that guarantee the successful filling using suggested finite element analyses.

Filling performance of solder paste in the stencil printing process is highly dependent on material properties such as viscosity and surface tension together with process parameters such as squeegee angle and squeegee speed. In order to investigate the effects of process parameters on the filling performance, the pressure built‐up under the squeegee and the filling procedure of the solder paste into an aperture were analysed. Due to the limitations of the computational memory and time, the analysis domain was simplified. The pressure development under the squeegee was investigated for various values of squeegee angle and speed; then, the filling behaviour with the pressure boundary condition was analysed for only one aperture. Finally, the two analysis results were integrated to obtain the successful filling condition. In this analysis method, process parameters that guarantee filling performance were decided on.

It was shown that higher squeezing pressure develops as the squeegee angle decreases and the squeegee speed increases. The filling performance, however, improves as the squeegee angle and the squeegee speed decrease. This is because the pressure duration time decreases as the squeegee speed increases.

This study suggests a new design approach to obtain proper process design parameters for successful filling of solder paste into an aperture. The direct analysis of filling with squeegee movement is impossible due to limitations of computer memory and computation time. To overcome these limitations, a two steps analysis approach is proposed and can be effectively applied in the design of stencil screen printing.

The purpose of this paper is to develop a coupled approach to solve the pressure–velocity-coupled problem efficiently in the three-dimensional injection molding simulation.

A fully coupled pressure–velocity algorithm is developed to solve the coupled problem, by treating the pressure gradient term implicitly. And, the Schur complement preconditioned FGMRES is applied to decompose the resulting coupled pressure–velocity equation into pressure and velocity subsystems. Then, BoomerAMG is adopted to solve the pressure subsystem, and block Jacobi preconditioned FGMRES is applied to the velocity subsystem.

According to the several experiments, the fully coupled pressure–velocity algorithm was demonstrated to have faster convergence than the traditional SIMPLE algorithm, and the calculating time was reduced by up to 70 per cent. And, the Schur complement preconditioned FGMRES worked more efficiently than block Gauss–Seidel preconditioned FGMRES, block-selective AMG and AMG with block ILU(0) smoother and could take at least 47.4 per cent less time. The proposed solver had good scalability for different-size problems, including various cases with different numbers of elements. It also kept good speedup and efficiency in parallel performance.

A coupled solver has been proposed to effectively solve the coupled problem in the three-dimensional injection molding simulation, which is more robust and efficient than existing methods.

A new, digital, weigh filling control system installed at Swift Adhesives in Cambridgeshire has enabled the Company to fill boxes of its hot melt glue produet more efficiently than a previous, pneumatic based system.

The importance of banking efficiency has been shown to have become increasingly relevant, not only for researchers but also for decision makers. However, the large number of combinations between the variables used and the different approaches considered to measure efficiency caused a divergence between authors regarding the inputs and outputs used. The paper aims to discuss these issues.

On the basis of a critical analysis of the main variables used in literature, this paper proposes a set of inputs and outputs to be used with consideration of the main approaches to banking efficiency.

Filling a gap in the literature, this study contributes to the development of future studies by suggesting variables which, in accordance with the theory related to banking efficiency, are highly suitable for creating relevant information for decision-making.

Frontier techniques are largely applied for assessing efficiency not only in large financial institutions, but also in bank branches and other regional units. Although a wide variation of articles follows a set of inputs and outputs without arguing for its suitability, this paper differs from the vast majority of applications by discussing the most reliable set of variables to represent efficiency levels.

For the past 45 years J. De Vree & Co., Antwerp, Belgium, have specialised in filling and packaging equipment for the Paint & Ink manufacturing industry. Now recognised as one of the World leaders in this field, the company's wide range of filling machines extend from simple semi‐automatic units through to highly advanced computer‐controlled equipment capable of speeds up to 120 containers per minute.