Search

Biomaterials and new processes (3D printing and flexible hybrid electronics) offer opportunities to break free from a 2D paper world by allowing for the development of smart multi-dimensional structures. While there has been recent progress reported in each of these areas of technology, to date, the merger of these technologies has been very limited. We believe that their merger offers boundless opportunities and an opportunity for the paper industry to innovate a low cost, sustainable housing solution capable of promoting the well-being of its occupants while minimizing the environmental impact of its daily use.

A piece of paper has many useful characteristics; it is affordable, lightweight, thin, strong, and highly absorbent. These features allow inexpensive and flexible devices to be fabricated easily and rapidly. We have proposed a new field, “paper mechatronics,” which merges printed robotics and paper electronics, and to realize electronic and mechanical systems by printing. Herein, we develop a method to print an actuator and a structure on a sheet of paper. A trilayer electrothermal actuator is printed to activate a printed robot. The paper self-folds along the printed pattern to form the three-dimensional (3-D) structure of the robot body. We also investigate important factors necessary to develop a printed robot. Experiments, including finite element analysis (FEA), confirm our bimetal modeling assumption for the printed actuator and improve the locomotive ability. The key factors in self-folding are paper thickness and humidity. Our findings can improve the reliability of printed robot designs. A self-folding A7-sized paper robot demonstrates locomotion at 10 mm per step.

Paper is a widely used packaging material and is nowadays regaining importance, e.g., as bio-based and biodegradable material. Moreover, new technologies such as polymerâfiber composites, printed electronics and the deep drawing of paper are developing. The process stability and also the resulting quality of paper converting processes such as coating, metallization, printing, and the printing of electronics are highly affected by the hygroexpansion of paper. In order to reduce production instability and to choose and develop paper substrates with ideal characteristics, critical parameters need to be known. This paper offers an extensive overview of those parameters, starting at a molecular and microscopic level with the effect of the constituents and morphology of single fibers, before moving on to paper contents, chemical modifications and additives and finally concluding with paper production and fiber network modification. It was found that the major influences are single fiber sorption, inter-fiber contacts, microfibril angle, fiber morphology (length, width, curliness) and fiber orientation. This review gives new ideas and insights for technologists working in research, development and production optimization of paper-based products.

Recently, there has been strong interest in printed robots and paper electronics. Printing is an adequate manufacturing method for the mass production; robots manufactured by printing can be low cost, rapidly creatable and easy to design. Paper is one of smart materials with high water absorbency and strength; it is easily mass-produced at low cost. Many inexpensive and flexible devices were created in paper electronics. Therefore, we propose paper mechatronics that merges printed robots and paper electronics. We used a commercial ink jet printer with water-based ink for self-folding of paper; the paper was folded automatically along the printed line to make the robot body. The paper robot was equipped with a printed electrothermal actuator that consists of epoxy resin covered by conductive ink. The epoxy resin was heated by Joule heat of the conductive ink under a driving voltage of 8 V. The self-folding of experimental paper robot took 15 minutes to construct the body and the robot demonstrated a locomotion at 6.5 mm per step. I. INTRODUCTION

Thermal recording paper typically used in facsmile system has been rapidly expanding to great proportions and has secured a firm position in an information-oriented society. This would result the systematic development between electronic technology in hardware industries and coating technology in paper industries including various raw material industries.The fine powdered silica, “Mizukasil”, has played an important role in the development of the thermal recording paper as a residue-preventing agent on a thermal head. Since this fine powdered silica has extremely fine particles and is inactive, it combines the following advantages in residue-prevention, sticking prevention, color-developing sensisivity, color intensity, dot minuteness, color gradient and runnability of the thermal head.

This special section of Journal of Micromechanics and Microengineering features papers selected from the 11th International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2011), held at Sejong Hotel in Seoul, Korea during 15–18 November 2011. Since the first PowerMEMS workshop held in Sendai, Japan in 2000, the workshop has developed as the premier forum for reporting research results in micro and nanotechnology for power generation, energy conversion, harvesting and processing applications, including in-depth technical issues on nanostructures and materials for small-scale high-density energy and thermal management. Potential PowerMEMS applications cover not only portable power devices for consumer electronics and remote sensors, but also micro engines, impulsive thrusters and fuel cells for systems ranging from the nanometer to the millimeter scale. The 2011 technical program consists of 1 plenary talk, 4 invited talks and 118 contributed presentations. The 48 oral and 70 poster presentations, selected by 27 Technical Program Committee Members from 131 submitted abstracts, have stimulated lively discussion maximizing the interaction between participants. Among them, this special section includes 9 papers covering micro-scale power generators, energy converters, harvesters, thrusters and thermal coolers. Finally, we are grateful to the members of the International Steering Committee, the Technical Program Committee, and the Local Organizing Committee for their efforts and contributions to PowerMEMS 2011. We also thank the two companies Samsung Electro-Mechanics and LG Elite for technical tour arrangements. Special thanks go to Dr Ian Forbes, the editorial staff of the Journal of Micromechanics and Microengineering, as well as to the staff of IOP Publishing for making this special section possible.

This special section of the Journal of Micromechanics and Microengineering presents papers selected from the 9th International Workshop on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS 2009), which was held in Washington DC, USA from 1?4 December 2009. Since it was first held in Sendai, Japan in 2000, the PowerMEMS workshop has focused on small-scale systems that process, convert, or generate macroscopically significant amounts of power, typically with high power density or high energy density. In the workshop's early years, much of the research presented was on small-scale fueled systems, such as micro heat engines and micro fuel cells. The past nine years have seen a dramatic expansion in the range of technologies that are brought to bear on the challenge of high-power, small-scale systems, as well as an increase in the applications for such technologies. At this year's workshop, 158 contributed papers were presented, along with invited and plenary presentations. The papers focused on applications from micro heat engines and fuel cells, to energy harvesting and its enabling electronics, to thermal management and propulsion. Also presented were the technologies that enable these applications, such as the structuring of microscale, nanoscale and biological systems for power applications, as well as combustion and catalysis at small scales. This special section includes a selection of 12 expanded papers representing energy harvesting, chemical and fueled systems, and elastic energy storage at small scales. We would like to express our appreciation to the members of the International Steering Committee, the Technical Program Committee, the Local Organizing Committee, and to the workshop's financial supporters. We are grateful to the referees for their contributions to the review process. Finally, we would like to thank Dr Ian Forbes, the editorial staff of the Journal of Micromechanics and Microengineering, and the staff of IOP Publishing for making this special section possible.

Electronics engineering is a very rapidly growing field, as the time passes the requirement of more advance technologies increase. There are a lot of institutions and universities around the world that provide quality education to different fields of engineering. The courses that electronics engineers study need practical exposure as well to cope up with industrial demands. In this paper, the role of multiphysics modeling and its impact on engineering education is demonstrated. Finite element modeling(FEM) tools are very powerful tools and due to there huge advantages, electronics graduates should study these tools in their course curriculum to know how to tackle various types of physics problems and through examples it is demonstrated that how these tools can help shift from just theory to development process.

An intelligent textile is a textile structure that measures and reacts in front of external agents or stimulus with or without integrated electronic equipment. . The finality of the present textile is to take one more step towards intelligent textile, considering the integration of electronics and textile needs, to be industrially viable and to keep up the necessary competitiveness, raising the final price as little as possible. The finality of these experiments is to develop a textile that varies in conductivity and resistance in relation to the elongation of the textile, detecting changes caused by the alteration of a piece of clothing, from the pressure of a finger on the material, for example. One of the most important characteristics of textile is the capacity of reproducing measures, of varying the response in different tests. Two lines of research were opened: the study of the most adequate structure to achieve a response that can be reproduced and the study of the best way of taking measures without altering the behavior of the textile.

In the current paper the reliability of spring interconnections for the use in automotive applications was investigated. A commercially available connector was used for contacting a piezo-jet printed silver pad on polycarbonate. The structures were tested using vibration tests at three different temperatures (−25°C, 25°C and 85°C) and measured using four-point probe measurement system and white light spectrometry. The obtained results showed the reliability of the printed structure and the contact, despite of the contact resistance change. The reasons of this change and experimental results are discussed in the paper. The investigations described in the paper provide an initial approach to the development of spring interconnections for printed electronics.

Purpose This paper aims to present a review of the recent developments in vapour phase soldering (VPS) technology. This study focuses on the following topics: recent developments of the technology, i.e. soft and vacuum VPS; measurement and characterization methods of vapour space, i.e. temperature and pressure; numerical simulation of the VPS soldering process, i.e. condensate layer and solder joint formation; and quality and reliability studies of the solder joints prepared by VPS, i.e. void content and microstructure of the solder joints. Design/methodology/approach This study was written according to the results of a wide literature review about the substantial previous works in the past decade and according to the authors’ own results. Findings Up to now, a part of the electronics industry believes that the reflow soldering with VPS method is a significant alternative of convection and infrared technologies. The summarized results of the field in this study support this idea. Research limitations/implications This literature review provides engineers and researchers with understanding of the limitations and application possibilities of the VPS technology and the current challenges in soldering technology. Originality/value This paper summarizes the most important advantages and disadvantages of VPS technology compared to the other reflow soldering methods, as well as points out the necessary further developments and possible research directions.

Almost 15 years have gone ever since the discovery of graphene as a single atom layer. Numerous papers have been published to demonstrate its high electron mobility, excellent thermal and mechanical as well as optical properties. We have recently seen more and more applications towards using graphene in commercial products. This paper is an attempt to review and summarize the current status of the research of the thermal properties of graphene and other 2D based materials including the manufacturing and characterization techniques and their applications, especially in electronics and power modules. It is obvious from the review that graphene has penetrated the market and gets more and more applications in commercial electronics thermal management context. In the paper, we also made a critical analysis of how mature the manufacturing processes are; what are the accuracies and challenges with the various characterization techniques and what are the remaining questions and issues left before we see further more applications in this exciting and fascinating field., YF, JH, YL, AZ, MK and JL acknowledge the financial support from The Swedish National Science Foundation (VR under the contract No 621-2007-4660), The Swedish Foundation for Strategic Research (SSF) under contract (No SE13-0061), the Swedish Board for innovation under the Siografen program and from the Production Area of Advance at Chalmers University of Technology, Sweden. SC, YZ and JL acknowledge the financial support by the Key R&D Development Program from the Ministry of Science and Technology of China with the contract No: 2017YFB040600 and the National Natural Science Foundation of China (No. 51872182). XX is supported the National Natural Science Foundation of China (No. 11674245 & No. 11890703). MS and CMST acknowledge financial support from the CERCA programme/Generalitat de Catalunya, the Severo Ochoa Centres of Excellence programme, funded by the Spanish Research Agency (AEI, Grant No. SEV-2017-0706).

This paper presents the analysis and optimization of multistage refrigeration thermal control system for use in cooling electronics payloads on Venus lander missions. The paper outlines the challen...

This paper address two significant applications of stencils in advance packaging field: 1. Ultra-Thin stencils for miniature component (0201m) assembly; 2. Deep Cavity stencils for embedded (open cavity) packaging. As the world of electronics continues to evolve with focus on smaller, lighter, faster, and feature-enhanced high-performing electronic products, so are the requirement for complex stencils to assemble such components. These stencil thicknesses start from less than 25um with apertures as small as 60um (or less). Step stencils are used when varying stencil thicknesses are required to print into cavities or on elevated surfaces or to provide relief for certain features on a board. In the early days of SMT assembly, step stencils were used to reduce the stencil thickness for 25 mil pitch leaded device apertures. Thick metal stencils that have both relief-etch pockets and reservoir step pockets are very useful for paste reservoir printing. Electroform Step-Up Stencils for ceramic BGA's and RF Shields are a good solution to achieve additional solder paste height on the pads of these components as well as providing exceptional paste transfer for smaller components like uBGAs and 0201s. As the components are getting smaller, for example 0201m, or as the available real estate for component placement on a board is getting smaller – finer is the aperture size and the pitch on the stencils. Aggressive distances from step wall to aperture are also required. Ultra-thin stencils with thicknesses in the order of 15um–40um with steps of 15um are used to obtain desired print volumes. Stencils with thickness to this order can be potential tools even to print for RDLs in the package. Cavity technology can be an effective solution in reducing the total assembled PCB thickness (Z-height), most importantly, on designs utilizing taller - stacked devices. Traditionally, dipping process or dispensing process was used to deposit solder paste, flux, or glue on uneven surfaces. However, this takes a longer time when compared to printing using a stencil printer. Reservoir printing using a stencil printer has greater potential in such application. Extensive work has been done in the past to print glue, solder paste and/or flux into cavities using reservoir printing. This paper focuses on printing solder paste into multiple cavities (stencil pockets) with depths ranging from 355 microns to 450 microns, and with varying cavity size, wall angles and various stencil thicknesses ranging from 100 microns to 150 microns. Apertures varying in area ratio were placed in these cavities and experiments were conducted to analyze the print performance of the stencils. As the size of the components and boards/substrates gets smaller - closer placement of components to the cavity (stencil pocket) walls needed to be assessed as well. These applications, the associated stencil design and print results were discussed in detail in this paper.

Multi-material 3D printing with electrically functional materials including conducting, sensing, insulating and semiconducting materials has led to the development of smart devices such as 3D structural electronics, sensors, batteries, etc. Electronically smart devices are a hot issue in 3D printing because they can certainly benefit from 3D printing technology, providing high design flexibility and customized functions. Shape-changing materials (e.g. shape memory polymers) incorporated in 3D printing have given birth to 4D printing, where 3D printed structures change in their shapes by external stimuli (temperature, light, water, etc.). The motivation of this review paper is to discuss mutual benefits from both 3D printed smart devices and 4D printed features, which can be built in a single body. It is expected that the combination of 3D printed smart devices and 4D printing would contribute to the development of high performance, adaptability to the environment and programmable 3D smart devices, which have not yet existed. This paper has reviewed the background of 3D printing, smart device fabrication using 3D printing, development into 4D printing, and future applications of 4D printing.

The main objective of the paper is to give an overview of prerequisites and enablers for individualized production from the perspective of flexible, agile and sustainable production of customized and personalized products. Increasing volatility in the global and local markets, shortening innovation and product life cycles, as well as a tremendously increasing number of variants, call for production facilities and networks and operations management which comply with these changing demands. The paper presents a set of developed concepts, methods and tools based on the recognized needs of manufacturing companies. The observed manufacturing domain is characterized with highly customized and personalized products produced in competitively in a high-cost country with short delivery times and high quality requirements. Micro and desktop factories can be seen as one type of solution to point-of-need manufacturing of customized and personalized products, such as hand-held consumer electronics or medical implants. The LeanMES concept and associated solution blocks aim for more efficient operation via digital tools. The Competitive Sustainable Manufacturing Hotel (CSM-Hotel) concept of a platform targeted for SMEs collaborating under same factory roof or in the same area. The A-NET vision offers a new holistic framework for industrial supply networks to manage development more agilely and for deeper strategic cooperation.

As the world's largest market for vehicles, China is facing challenges related to energy security and urban air pollution. The development of electric vehicles has been determined to be the national strategy for solving these problems. By the end of 2015, China had become the world's largest electric vehicles market, but its core technologies are still less competitive in the global marketplace. A scientific national strategy for 2016 to 2020 is expected to play a critical role in China becoming the global leader in the electric vehicle industry. The research process for this strategy includes a review of the technologies for electric vehicles, market analyses, benchmarking of the top levels in the field, and expert interviews. By these approaches, the strengths and weaknesses of China's electric vehicle technologies and industry are assessed. Competitive and feasible quantitative goals for key components and powertrains are proposed by this paper, and a core issue has been determined to be the need to improve the safety of high-energy density traction batteries. Improving the power density of electric control units is expected to the core for electric vehicles' electronics and control systems. Key problems for the fuel cell stacks used in cars and buses have been identified by this paper to be, respectively, power density and durability. Long-range plug-in hybrid electric powertrains are the optimal candidate for Chinese plug-in hybrid electric vehicles. Lightweight material, intelligent driving technologies and special electric chassis are set to be the focus for improving the energy efficiency of battery electric vehicles. Comprehensive safety and recyclable electric vehicle technologies are set to become key issues in the future, and the Chinese government should research and develop these in advance.

The continuing increase of functionality, miniaturization, and affordability of handheld electronic devices has resulted in a decrease in the size and weight of the products. As a result, printed wiring assemblies (PWAs) have become thinner and more flexible, and clearances with surrounding structures have decreased. Therefore, new design rules are needed to minimize and survive possible secondary impacts between PWAs and surrounding structures because of the consequential amplification in acceleration and contact stress. This paper is the first of a two-part series and focuses on the drop test reliability of commercial off-the-shelf microelectromechanical systems (MEMS) components that are mounted on printed wiring boards (PWBs). Particularly in this paper, we are interested in gaining preliminary insights into the effects of secondary impacts (between internal structures) on failure sites in the MEMS assemblies. Drop tests are conducted under highly accelerated conditions of 20 000 ${g}$ (“ ${g}$ ” is the gravitational acceleration). Under such high accelerations, the stress levels generated are well beyond those expected in conventional qualification tests. Furthermore, secondary impacts of varying intensities were allowed by changing the clearance between the PWB and the fixture. As a result, the stress and accelerations are further amplified, to mimic unexpected secondary impacts in a product if/when design rules fail to avoid such conditions. The amplification of the test severity is quantified by comparing the characteristic life ( $\eta $ in a Weibull distribution) of all the tested MEMS components at each clearance. Multiple failure sites from drop testing are identified, from packaging-level failures to MEMS device failures. The participation of competing failure sites is also demonstrated via characteristic life representations of each failure site at various clearances.

The performance of electronic applications used in extreme temperatures and ruggedised environments can be constrained by the operating temperature of the microprocessor device. Without an efficient thermal management path the operation of the microprocessor can be limited to 30–40% of its operating capacity in these environments. Traditional methods of dissipating heat rely on heat pads or spreaders, usually made of copper or aluminium placed in contact with the top surface of the microprocessor and linked either directly or via heat pipes to the outside environment via the housing. Whilst this ensures a potentially good thermal path it does not guarantee good electrical isolation which is necessary to prevent shorting. The commonly adopted solution is the use of thermal pastes which whilst providing electrical insulation only offer at best reasonable thermal conduction and hence become the limiting factor in the heat path. In addition, these thermal pastes are transient; in other words, they can move about under load and vibration and eventually be completely displaced from the target area leading to short circuiting of the device.As reported in previous work1, a thick, hard and well adhered amorphous diamond coating is a viable material for such applications and is commercially available through Diamond Hard Surfaces Ltd. The work reported in this paper looks at a new form of amorphous coating designed for applications requiring electrical resistance whilst operating at voltages in excess of 500V combined with the use with new MMC (Metal Matrix Composite) materials with potentially better conduction characteristics than Copper or Aluminium as substrates. The paper discusses the experiments undertaken to look at the development of a new amorphous coating using the PA-CVD process and the outcome of tests carried out of the material itself and in situ on test boards.

As various international and government institutions have decreed that electronic devices must adhere to electromagnetic safety standards before they enter the market, electromagnetic shielding has become an important aspect of design considerations. Various materials at different price points have specific characteristics that may cause them to become either optimal or ill-fitting for specific applications, however, testing their shielding capability can be difficult without the expensive equipment in testing facilities. In this paper, a handheld electromagnetic (EM) meter was used in a simplified test set up to assess the shielding effectiveness of 6 shielding materials: silver sleeve, steel mesh, conductive ABS, Al tape, and Al metallised film. Silver sleeve, Al tape, and Al metallised film were chosen to shield a robotic medical device based on their shielding capability, cost-effectiveness, and design flexibility. The CISPR 11 radiated emissions test results of the robotic medical device validated the shielding effectiveness of the materials chosen showing that the handheld EM meter was able to assess the materials’ shielding capability.As various international and government institutions have decreed that electronic devices must adhere to electromagnetic safety standards before they enter the market, electromagnetic shielding has become an important aspect of design considerations. Various materials at different price points have specific characteristics that may cause them to become either optimal or ill-fitting for specific applications, however, testing their shielding capability can be difficult without the expensive equipment in testing facilities. In this paper, a handheld electromagnetic (EM) meter was used in a simplified test set up to assess the shielding effectiveness of 6 shielding materials: silver sleeve, steel mesh, conductive ABS, Al tape, and Al metallised film. Silver sleeve, Al tape, and Al metallised film were chosen to shield a robotic medical device based on their shielding capability, cost-effectiveness, and design flexibility. The CISPR 11 radiated emissions test results of the robotic medical device validated th...

Fuel cells technologies are the most promising green energy technologies for diverse applications. One of the fastest growing areas is the portable electronic applications where the power range is the order of 1–100 W. For most of the portable electronic devices, rechargeable battery is the major energy source. Due to limitations like limited capacity, requirement of external power for recharge have led many researchers to look for alternative power sources to power portable electronic devices. The high energy density of fuel cells makes them very attractive alternative to batteries for portable power applications. There are a variety of fuel cell technologies being considered to replace batteries in portable electronic equipment. Direct Liquid Fuel Cells (DLFCs) have attracted much attention due to their potential applications as a power source for portable electronic devices. The advantages of DLFCs over hydrogen fed PEM fuel cells include a higher theoretical energy density and efficiency, a more convenient handling of the streams, and enhanced safety. Unlike batteries, fuel cells need not be recharged, merely refueled. This paper provides an overview on challenges of DLFCs (Direct Liquid Fuel Cells), like fuel crossover, cost, durability, water management, weight and size along with approaches being investigated to solve these challenges. Portable Fuel Cell Commercialization Targets for future and producers of portable fuel cells across the globe are also discussed in this paper.