Electronic Printed Circuit Boards Research Articles

Development a prototype of the basic platform of the autonomous intelligent robotics system (AIRS)

This work is devoted to the development of a prototype of the basic platform of the autonomous intelligent robotics system (AIRS). The frame of the experimental basic platform was made, main units and aggregates location was determined, testing of mechanical units and aggregates was carried out. Ultrasonic and infrared rangefinders were used to determine the distance to the object. The calibration of the sensors was performed when interacting with objects made of different materials, at different angles of the surfaces of these objects, and under different envi-ronmental conditions. An electronic printed circuit board has been developed to connect various sensors to an au-tonomous mobile robotic platform. The overall dimensions of the platform are 780x650x550 mm. The small size of the mobile basic platform allows it to be used on small sites where the use of other machines is economically unprofitable.

Selective Recovery of Copper from the Mixed Metals Leach Liquor of E-Waste Materials by Ion-Exchange: Batch and Column Study

Recovery of metals from e-waste forms a major focus of circular economy thinking and aligns well with the Sustainable Development Goals (SDG). While hydrometallurgical extraction from electronic printed circuit boards (PCBs) is well established, the separation of metals from the leach liquors, which are complex mixtures, remains a challenge. To achieve selective separation, ion exchange resins with chelating functional groups were employed in the present study. Batch and column studies for selective recovery of Cu2+ from a given mixed metals leach solution were conducted using Dowex M4195 resin, and both the adsorption isotherm and kinetics were studied. The process involves three major steps: selective recovery of Cu2+ by M4195 at low pH and elution with H2SO4; sorption of Ni2+ from the raffinate by Dowex M4195 at pH 2 and removal of Fe3+ from raffinate. The batch experimental results showed appreciable and selective recovery of copper (51.1%) at pH 0.7 and 40.0% Ni2+ was sorbed from raffinate at pH 2.0 with co-adsorption of Fe3+ as impurity. The batch adsorption data could be fitted with both Langmuir and Freundlich isotherms and exhibited pseudo-second-order kinetics. Column studies agreed with the Yoon–Nelson model and indicated that Cu2+ break-through time in the column decreased with an increase in flowrate from 3.0 to 10.0 min/mL and decreased in sorption capacity, while it was delayed with increased bed heights from 20 to 30 mm. Complete elution of Ni2+ was obtained with 2.0 M H2SO4 after selective elution of trace impurities with dilute HCl. Iron in the raffinate was removed via the addition of Ca (OH)2 at pH 4.0 leaving Zn-Al in the solution.

FPGA-Based Optimization of Industrial Numerical Machine Tool Servo Drives

This paper presents an analysis of the advantages stemming from the application of field-programmable gate arrays (FPGAs) in servo drives used within the control systems of industrial numerical machine tools. The method of improving the control system that allows for increasing the precision of machining, as well as incorporating new functionalities and streamlining diagnostic processes, is described. As demonstrated, the utilization of digital controllers with robust computational power and high-performance real-time communication interfaces is essential for achieving these objectives. This study underscores the limitations of commonly employed digital controllers in servo drives, which are constructed based on microcontrollers or signal processors collaborating with application-specific integrated circuits (ASICs). In contrast, the proposed FPGA-based solution offers substantial computational power and significantly reduced latencies in the real-time communication interface compared to other examined alternatives. This enables the realization of the planned objectives, specifically the enhancement of technical parameters and diagnostic capabilities of machine tools. Furthermore, the research indicates that FPGA-based digital controllers exhibit relatively low power consumption and a simplified design of the electronic printed circuit board in comparison to other analyzed digital platforms. These features can contribute to heightened reliability and diminished production costs of such controllers. Additional conclusions drawn from the study indicate that FPGA-based controllers provide greater developmental possibilities and their production is marked by potential resilience to challenges associated with the availability of electronic components in the market.

Experimental investigation of modified bitumen in flexible pavements by using electronic waste and high impact polystyrene

At present the use of Electronic printed circuit board (E-PCB) and High Impact Polystyrene (HIPS) is increased due to digitalempowerment to every citizen and corporate governance. The disposal of E-PCB and HIPS becomes a major threat to the environment without proper recycling. The reprocess of the waste material in the construction sector is most popular in the recent years. The current work was focused on the use of E-PCB powder as a partial replacement of VG30 bitumen and to modify the properties of bitumen. Stability of the modified bituminous mixes was found by replacing E-PCB non-metallic chips and High Impact Polystyrene in course aggregate. The basic properties of bitumen (Ductility, Specific gravity, penetration, viscosity, softening point, flash and fire point)and Marshall Stability of modified bituminous mixes was studied with various percentage of E-PCB non-metallic chips and High Impact Polystyrene. The result shows that increase of E-waste and HIPS will improve the stability and properties.

A Double-Needle Gold-Silver Electrodes Continuous Glucose Monitoring Device

ObjectivesDiabetes is a serious, long-term disease and the use of continuous glucose monitoring sensors can reduce reliance on other painful invasive blood testing methods such as the finger blood glucose test. According to our work, a low-cost continuous glucose sensor has been developed based on electrochemical measurement techniques. MaterialsThe sensor is based on a two needles system; a gold and a silver electrode are integrated into a circular shaped electronic printed circuit board (PCB). The sensing part is based on biological electrochemical measurements. Glucose oxidase (Gox) was used as the active sensing element and ferrocene (Fc) as a mediator. Simple and low-cost coating methods were used; these methods are self-assembled monolayers and deep coating. This will reduce the final cost of the sensor as no expensive technique was used. The electrical subsystem contains a low-noise and low-power trans-impedance front-end as well as a single-chip low-power Bluetooth microcontroller with a 12-bit Analog-to-Digital Converter (ADC). ResultsThe sensor was tested in various concentrations of glucose. As a result of initial in vitro experiments, detailed analytical performance metrics are presented. The device has consistently shown a sensitivity of 3.059 mV/(mg/dl) reading with a linear range of 0-400 mg/dl. ConclusionThe proposed study shows promising results for glucose detection. Thus, this type of sensor can be used for different analyzes targeting biological applications after further investigations and analysis.

Growth of YBa2Cu3O7-δ superconducting films under different atmospheres by pulsed laser deposition

This paper aims to explore the epitaxial growth process for high-temperature superconducting YBa2Cu3O7-δ (YBCO) thin films by pulsed laser deposition (PLD) under different deposition atmospheres. The possibility of depositing YBCO superconducting thin films, under an oxygen-free environment, that was different from the oxygen atmosphere for most deposition processes of YBCO superconducting thin films was studied. Three different atmospheres, with oxygen, nitrous oxide, and nitrogen, were used in the experiment. The influence of atmospheric pressure on the formation and superconductivity of the YBCO phase were studied in detail. The characterization of structure and electrical properties of the thin films showed that YBCO thin films showed highly preferentially growth along the c-axis, had good superconductivity, and could be prepared under all three atmospheres. The formation of the YBCO phase at high temperatures did not need oxygen, and subsequent low-pressure oxygen-annealing process was only required at low temperatures of about 350 ℃. Our findings are of great significance for the preparation and application of YBCO thin films on substrates that were easy to oxidize at high temperatures, such as nickel strips or some electronic printed circuit boards.

Design and Validation of a Modular Control Platform for a Voltage Source Inverter

Integrating renewable energies, such as wind or photovoltaic, requires an electronic power converter, the three-phase Voltage Source Inverter (VSI) the most common for such function. This paper presents a modular design of signal acquisition and control hardware (current and voltage) for the commercial SEMIKRON SKS35F VSI converter and a Texas Instruments TMS320F28335 DSP. Consequently, the proposed modular and open-source design allows its application in control systems of a VSI converter for isolated or grid-connected systems, applied to power generation based on renewable sources. The proposed scheme allows for a personalised design since it uses an open architecture to implement its own control algorithms that allow it to adapt to the application’s particular needs, unlike closed-architecture commercial equipment. Detailed electronic printed circuit board designs for implementation are shown on paper. Finally, the experimental tests’ results that validate the proposed design’s correct functioning are presented.

Numerical simulation and validation of MWCNT-CFRP hybrid composite structure in lightweight satellite design

Aluminum alloy is generally used in electronic housings of satellites in space avionics due to its remarkable mechanical, thermal, electrical, and radio-frequency shielding properties. This paper proposes a design for a lightweight multi-functional electronic housing made from plastic containing multi-wall carbon nanotubes (MWCNT) composite material. The structural design of housings was validated against a set of boundary conditions and requirements of launch and space environments as prescribed by European Cooperation for Space Standardization (ECSS) standards. The proposed concept for lightweight composite housing was designed with special emphasis on reducing machining operations. The composite housing offers a mass saving of ∼25 % over a typical aluminum housing with similar mechanical performance in the three orthogonal directions. The modal frequency is greater than 100 Hz qualifying the design requirement for satellite electronic housings. Under sinusoidal vibration loads, the structure shows no noticeable excitation in acceleration response graph, indicating no resonance in low-range frequencies from 5 to 100 Hz. Maximum stresses obtained from Quasi-static and random vibration loads are within the tensile strength limit in the three orthogonal directions. In addition, maximum deflection observed in electronic printed circuit boards is within the 1 mm design requirement.

Trustworthiness of machine learning models in manufacturing applications using the example of electronics manufacturing processes

The design phase of products decides about a large portion of their costs. Both applied manufacturing technologies and systems are ultimately defined by the products that have to be assembled. Due to global trends towards e-mobility and regenerative energy, electronic printed circuit boards with high copper content and mixed SMT/THT assembly is the predominant assembly scenario. This leads to thermally challenging soldering operations in THT-soldering as high copper masses dissipate the required heat and no reliable manufacturability check is available. Consequently, in electronic manufacturing complex thermal processes have still to be defined in iterative experimental steps. Reliable models have great potential to reduce time-to-market and scrap during new product introduction. Future manufacturing systems require infrastructure that allows manufacturability checks in the early design phase and automatically provides process programs on the shop floor once the design is finished. However, the lack of availability, long-term experience and consequently trust in automatically, by artificial intelligence generated and optimized process programs, blocks the realization and hinders further productivity gain. In this paper, an ML audit methodology is suggested that mitigates this lack of trust by providing physically plausible prediction series and quantitative risk assessment to the user. This complements typical evaluation scores and adds the model behavior in the process context and transmits a sense of transparency. A neural network is trained with an augmented dataset, exemplary for the prediction of the hole fill in mini wave soldering process. The model is then used to predict series of predictions for increasing soldering time and temperatures comparable to design of experiments. The resulting time versus hole fill plots helps the operator understanding the behavior of the model and thus, demonstrate the potential benefit of this approach to the entire manufacturing site.

Influence of E-waste on properties of bituminous mixes

In the past decade, the use of E-Waste is increased due to the increase in usage of electronic components to a greater extent. The large quantity of damaged Electronic printed circuit boards (E-PCB) is discarded into the environment without proper recycling treatment in many places. The reuse of E-PCB waste in the construction industry is the most common practice nowadays. The present study focused on partial replacement of bitumen with E-PCB waste to a certain percentage in the form of fine powder and non-metallic chips. The bitumen was replaced by the various percentage of E-PCB waste as a fine powder to attain the optimum value. The optimum value is used as constant to replace the coarse aggregate of bituminous mixes with E-PCB non-metallic chips. This study investigates the properties of bitumen (includes penetration value, ductility, softening point, flash & fire point, and industrial viscosity) and Marshall stability of various bituminous mixes. The replacement of bitumen with E-waste resulting in the improvement of Marshall stability and flow value of bitumen.

Investigation on Drilling Behavior of CFRP Composites Using Optimization Technique

Carbon fiber-reinforced polymers (CFRPs) have been applied to various fields such as electronic printed circuit boards, aircraft brakes, automobile forks, and machine tool-damped structures due to their low density and high tensile strength. These application components required micro-hole and macro-hole in it for joining. In this research work, a comparison of the experimental investigation on micro- and macro-drill on CFRP using a vertical machining center has been carried out. The input machining control factors were spindle speed and rate of feed, whereas the quality characteristics of drilling CFRP were considered as thrust force, delamination, and overcut. Analysis of variance (ANOVA) and gray relational analysis were employed to identify the most significant factor and optimum process parameters, respectively. Microstructural defects of micro-hole and macro-hole were studied using scanning electron microscopy. Results showed that the rate of feed linearly affected the thrust force and delamination and is inversely proportional to overcut.

Automated line integration from through hole technology to integrated circuit testing

Through Hole Technology (THT) is a method in electronic printed circuit board (PCB) mounting technology by which components are mounted on the PCB board and it is later sent for Integrated circuit testing (ICT). The in-process material movement is the real culprit for decreased production rates. Here we discuss the various identified reasons for the same and calculated effective possible maximum production rates and improvise the process with the help of an automated material transfer system and validate the same using production simulation software called Tecnomatix. Each of the system i.e. the manual and the automated system was studied, and appropriate corrective decision was taken to improvise the overall productivity.

Laser + Camera = Innovation

AbstractThe use of modern laser technology has become standard in industrial manufacturing thanks to its speed, accuracy and effectiveness. Lasers are used to engrave parts, electronic printed circuit boards or chip cards. They perforate packaging, structure semiconductor wafers, drill, cut and weld plastics or metals, and create highly complex structures via 3D printing — all contactless, with no application of force and wear‐free.

Non‐unicity of the electric near‐field planar emission model with dipole array

This study deals with the behavioural modelling of the planar electric- (E-) near-field (NF) emission from electronic printed circuit boards. The methodology indicating how to synthesise the model from the given scanned E-NF maps in the observation plane of interest is established. The modelled radiation source is built with exclusively E-dipole array whose components are determined by the inverse method. After computational routine algorithm Matlab implementation, the proposed model was validated with various demonstrators. Relevant verifications were performed at different operating frequencies with the E-NF emission from analytical radiation, measurement scanning with active complex RF PCB and full wave simulation with microwave passive microstrip structure. It was shown that the model enables to reproduce the equivalent source with relative error vector magnitude accuracy less than 3%. The error analyses in function of the distance between the observation plane and the radiating PCB were proposed. Moreover, the non-unicity and limit of the model with the E-field emission prediction from different E-field radiated data defined in the scanning observation surface plane positions from the radiating circuit. The developed model can be potentially used to lower the cost of EM compatibility engineering during the electronic PCB design phase.

Comparison of Thermal Properties of PCB Photoresist Films Cured by Different Techniques

The possibility of implementing microwave technology to photoresist film curing which is a major process in the production of electronic printed circuit boards (PCB) was investigated and compared with a conventional curing method, e.g. UV lithography. Since both techniques involved irradiation, hot plate curing which relies on thermal conduction was undertaken to study the effect of a heat transfer approach. Two film thicknesses were studied, i.e. 0.0012 and 0.002 inch, and the effects of curing power and time were investigated. Thermal properties, i.e. percent cure, glass transition temperature (Tg), composition and degradation temperature (Td), were evaluated using a Differential Scanning Calorimeter (DSC) and Thermogravimetric Analysis (TGA) and it was found that the commercial UV irradiation was sufficient to completely cure the thin film but only reached 76% cure for the thicker film, resulting in a lower Tg. The results show that the required processing conditions using a conventional household microwave to obtain almost complete curing were 1,000 Watts and 10 minutes curing time. In addition, improved curing was achieved in the thicker film because microwave can transmit into polar materials whereas UV cannot penetrate very far into the material. The hot plate curing was observed to produce a higher degree of curing and Tg, however, the uniformity of heating was found to be a major limiting factor of this technique. Slight differences in decomposition profiles of the films cured by different techniques implied slight differences in molecular structures. Compared to UV and hot plate curing, microwave technology was demonstrated as a potential curing technique in the production of PCBs due to its ability to efficiently cure thick films resulting in a strong material with high Tg. To apply the technique to other processes, optimal conditions, i.e. power and time, should be further investigated as well as the prevention of hot spots.

Decomposition of no-clean solder flux systems and their effects on the corrosion reliability of electronics

No-clean flux systems are used today for the soldering of electronic printed circuit board assemblies assuming that all the aggressive substances of the flux will vanish during the soldering process i.e. evaporate, decompose or being enclosed safely in the residues. However this is not true in most cases, as the flux residue left on a printed circuit board assembly is a key factor compromising the corrosion reliability under humid conditions. This investigation focuses on the chemical degradation of three kinds of solder flux systems based on adipic, succinic, and glutaric acid as a function of temperature, thus simulating the soldering process. Differential Scanning Calorimetry, Fourier Transform Infrared Spectroscopy, and Ion Chromatography were employed for decomposition and residue analysis. Aggressiveness of the residue was investigated using a pH indicator gel test and by acid value determination. Effect on corrosion reliability was investigated by exposing the test printed circuit board assemblies to humidity after pre-contaminating with pure acids and desired solder flux systems and measuring the charge transferred between electrodes under applied potential bias. Results showed that the fluxes do not decompose fully within the temperature regime of the soldering process, leaving behind significant level of weak organic acid residues. The residue depending on the type and amount can be can be very aggressive towards the corrosion on the printed circuit board assemblies. The glutaric acid based flux showed highest leakage current when exposed to humidity compared to the adipic and succinic based fluxes.

LTCC/PZT accelerometer in SMD package

Purpose – The purpose of this paper is to develop the device made of low temperature co-fired ceramics (LTCC) and lead zirconate titanate (PZT) by co-firing both materials. In the paper, the technology and properties of a miniature uniaxial ceramic accelerometer are presented. Design/methodology/approach – Finite element method (FEM) is applied to predict properties of the sensor vs main dimensions of the sensor. The LTCC process is applied during manufacturing of the device. All the advantages of the technology are taken into account during designing three-dimensional structure of the sensor. The sensitivity and resonant frequency of the accelerometer are measured. Real material parameters of PZT are estimated according to measurement results and FEM simulations. Findings – The ceramic sensor integrated with SMD package with outer dimensions of 5 × 5 × 5 mm3 is manufactured. The accelerometer exhibits sensitivity of 0.75 pC/g measured at 100 Hz. The resonant frequency is equal to about 2 kHz. Useful frequency range is limited by 3 dB sensitivity change at about 1 kHz. Research limitations/implications – Sensitivity of the device is limited by interaction between LTCC and PZT materials during co-firing process. The estimated d parameters are ten times worse comparing to bulk Pz27 material. Further research on materials compatibility should be carried out. Practical implications – The sensor can be easily integrated into various devices made of standard electronic printed circuit boards (PCBs). Applied method of direct integration of piezoelectric transducers with LTCC material enables manufacturing of complex ceramic systems with built-in accelerometer in the substrate. Originality/value – The accelerometer is a sensor and a package simultaneously. The miniature ceramic device is compatible with surface mounting technology; hence, it can be used directly on PCBs for vibration monitoring inside electronic devices and systems.

A Combined Method-of-Moments and Near-Field Measurements for EMI Evaluation of Switched-Mode Power Supplies

We propose an efficient modeling technique for the evaluation of radiated electromagnetic interference due to a switch-mode power supply mounted on a typical electronic printed circuit board (PCB). In the proposed model, first, the measured magnetic field on a rectangular plane in the vicinity of the PCB is used to identify equivalent current sources on the board surface by the method-of-moments. Having determined the radiating sources, the governing integral equations in free space are then utilized to compute the magnetic-field distribution at a desired distance from the PCB. The main feature of the proposed model is the use of both the magnitude and phase of the near-magnetic field for identifying the unknown current sources. This is found to be advantageous over the conventional models where the measurements are done on two separate planes or involve time-consuming heuristic optimization algorithms to invert the measured magnetic-field data into unknown current sources. The validity of the proposed technique is demonstrated by comparing the actual and reconstructed field radiations due to several simulated and fabricated sources.

FULLY TIME-DOMAIN SCANNING OF EM NEAR-FIELD RADIATED BY RF CIRCUITS

This paper deals with planar scanning technique of electromagnetic (EM) near-fleld (NF) emitted by electronic printed circuit boards (PCBs) fully in the time-domain (TD). The proposed EM scanning metrology is essentially based on the NF test bench available at the IRSEEM laboratory. It comprises motorized mechanical structures for moving the probe interconnected to electronic measurement instruments and controlled by a driver PC. The synoptic of the test bench is presented and technically examined. The characteristics of difierent elements constituting the measurement chain of the TD test bench understudy are described. The NF metrology developed is originally focused on the measurement of time-dependent magnetic fleld H(t) dedicated to the radiated emission electromagnetic compatibility (EMC) applications. An innovative calibration technique of the loop probe for detecting H(t) is established in order to ensure the post processing and extraction of the measured NF data. Then, validations were carried out via comparison with difierent simulations run with standard commercial tools. Mathematical analyses were also conducted for the improvement of the measurement post processing. To realize the mapping of time-dependent EM fleld components, a software interface edited with the graphical language LabVIEW was emulated to synchronize the probe displacement and the data acquisition. An UWB amplifler with average gain about 30dB from DC to 300MHz was designed and fabricated in order to decrease the measurement noise and to improve the quality of measured signals. As results of the study, TD NF mapping is demonstrated successfully by measuring the EM radiation emitted by electronic planar circuits. The technique developed is extremely useful in the fleld of EMC engineering for predicting the transient perturbations susceptible to degrade electronic functions in complex systems encountered usually for the automotive and aeronautic applications.

A Novel Recycling Approach for Transforming Waste Printed Circuit Boards into a Material Resource

The recovery of materials from urban waste has become progressively more important with wastes providing a variety of resources. This study focuses on the recycling of electronic printed circuit boards (PCBs) from mobile phones, computers, TVs, white goods, and micro-processors etc. that contain significant amounts of hazardous/toxic components along with a variety of metals, ceramics and polymers. Both formal and informal sectors are engaged worldwide in recycling such e-waste to recover precious and other metals (upto 40-70% of value). However poor recycling techniques, especially in developing countries, generate high levels of environmental pollution that affects both the ecosystems and the people living within or near the main recycling areas. Various e-waste recycling methods used in the informal sector include manual dismantling, open burning of PCBs, plastic chipping and melting, burning wires to recover copper, acid & cyanide salt leaching, and inadequate metallurgical treatments. These activities release dust particles loaded with heavy metals and flame retardants into the atmosphere that may re-deposit near the emission site, or be transported over long distances depending on their size. Significant levels of environmental pollution are thus associated with recycling e-waste.This study presents an environmentally sustainable solution to e-waste management and reducing associated pollution during recycling. In this study, waste PCBs were heat treated in the temperature range 1150-1350oC for periods of up to 20minutes in an Argon atmosphere. Key metallic constituents namely Cu, Sn and Pb showed a tendency to segregate out in the form of copper rich and Sn rich metallic balls. Minor elements such as Al, Fe, Mg, Ni, Pd, Pt and Zn segregated along with metallic droplets. Such high temperatures led to the removal of hazardous lead and the recovery of highly concentrated copper alloys and precious metals. Pyrolysis of PCBs also generated a carbon rich residue containing traces of Sn and very low levels of copper. Various ceramic impurities present precipitated out as slag and did not interfere with metal recovery.