Ioan Plotog - Academia.edu (original) (raw)

Papers by Ioan Plotog

The studies regarding magnetic field (MF) biotechnological applications in the range of Extremely... more The studies regarding magnetic field (MF) biotechnological applications in the range of Extremely Low Frequency (ELF: 3Hz to 300Hz, ITU Recommendation V.431-7) were generally based on Helmholtz coils (HC) systems in order to obtain a constant intensity for a determined volume. The paper presents the comparative studies of HC and Maxwell coils (MC) consisting in modelling, simulations and measurements of MF intensity. For this the geometry of the external coils of the MC system was designed identically with HC type. Based on the obtained results, there are defined the internal field intensity distribution for both coils systems used to design biotechnological applications.

2019 42nd International Spring Seminar on Electronics Technology (ISSE)

Solderless assembly for electronics is a subject approached ever since RoHS EU Directive enforced... more Solderless assembly for electronics is a subject approached ever since RoHS EU Directive enforced lead-free technology especially since this one has revealed its limits. Electrically Conductive Adhesives (ECA) actually with a large commercial offer but not very well characterized, became one of the alternatives to lead-free. The paper presents ECA qualification methods from mechanical and electrical properties point of view for usage as promising solution to build the electronic module, optimum on Surface Mount Technology processes or in the Occam concept using an additive process for interconnection structure. For a complete information about the bonds mechanical failure and their electrical resistance, shear tests, respectively four point electrical measurements were performed.

2017 IEEE 23rd International Symposium for Design and Technology in Electronic Packaging (SIITME), 2017

Under the current conditions of reducing manufacturing costs and complying with the RoHS 2 EU Rec... more Under the current conditions of reducing manufacturing costs and complying with the RoHS 2 EU Recast Directive in the automotive industry, without compromising functionality and reliability, it has become necessary to create a new Lead-Free Solder Pastes family [1]. Mechanical and thermal solder joints functionalities are determined by the microstructure morphology. In this respect, the paper presents the phases morphology as function of cooling rate in Vapour Phase Soldering Process (VPSP), for three alloys coming from the solder pastes: ALPHA® OM-6106 (Sn62), ALPHA® OM-340 (InnoLot) and ALPHA® OM-535 (SBX02). The presented work extends the theoretical studies and experiments upon phase morphology in VPSP, in order to optimize soldering process of automotive electronic modules. The results could be extend for home and modern agriculture appliances industry [2].

2016 IEEE 22nd International Symposium for Design and Technology in Electronic Packaging (SIITME), 2016

The maximum temperature of all parts of automotive electronics equipment is given by the location... more The maximum temperature of all parts of automotive electronics equipment is given by the location and can vary between 358 K and 478 K. RoHS EU Directive in the context of the manufacturing costs reduction, necessity led automotive industry to create new Low-Temperature Lead-Free (LTLF) solder pastes family. In the paper, the thermophysical properties of the alloys from ALPHA® CVP-520 (SnBiAg) and ALPHA® OM-535 (SBX02) test samples having as a source solder pastes were compared with similar from ALPHA® OM-6106 (Sn62) solder paste. The presented work extend the theoretical studies and experiments upon heat transfer in VPSP in order to optimize the technology for soldering process (SP) of automotive electronic modules and could be extended for home and modern agriculture appliances industry.

2008 31st International Spring Seminar on Electronics Technology, 2008

In the last decade new materials were launched on the market. This is the case of PCB substrates,... more In the last decade new materials were launched on the market. This is the case of PCB substrates, also. Requirements for improved heat transfer between power components and the solid metal base led to a new PCB technology, on copper and aluminum substrates. Typical applications are those where high level of heat has to be dissipated from the circuit (in

2018 41st International Spring Seminar on Electronics Technology (ISSE), 2018

The paper presents the mechanical and electrical properties of the joints as function of curing t... more The paper presents the mechanical and electrical properties of the joints as function of curing temperatures. These are made by printing a SW180 type ECAP (Electrically Conductive Adhesives Pastes) on printed circuit boards (PCBs) having daisy chain interconnection structures: one type of structure realized by printing ECAP on FR4 support, the chip components being placed into ECAP volumes corresponding to pads zones, the other type was etched using classical PCB technology in two hot air solder leveling (HASL) finishing types, leaded and lead-free. The micro-sections analysis of electrical joints and the microfractography analysis after shear testes performed on zero ohms, 1206 casing chip components are presented and interpreted. The database created as experiments results assures much better understanding of ECAP bonding processes as function of their curing temperature and offers the possibility to increase the reliability of ECAP applications in electronics.

2014 IEEE 20th International Symposium for Design and Technology in Electronic Packaging (SIITME), 2014

Taking into account the real working temperatures from different zones and daily requirement of r... more Taking into account the real working temperatures from different zones and daily requirement of reduction of production costs, into automotive electronics production the trend is the one towards low melting point alloys that will enable energy savings and cost reductions during the manufacturing processes. In the paper, the mechanical strength of solder joints and samples having the same transversal section as resistor 1206 case type made using Low Temperature Lead-Free (LTLF) solder pastes into VPS processes characterized by different cooling rates, were benchmarked according to temperature. The experiments were done in line with the concept of "Homologous temperatures", by measuring LTLF solder joints and alloys samples shear forces keeping the samples, respectively the surface of test boards at temperatures of up to 398K (125°C) using a dedicated auxiliary device, specially designed and manufactured to complete the multifunctional bond tester “Condor 70-3”, XYZTECH. The results of the experiments regarding references values of LTLF solder joints and alloys samples shear forces offer a data base useful in the new solder alloy creation processes and their qualification for automotive electronics domain according to RoHS 2 EU Directive.

INCAS Bulletin, Mar 10, 2016

The paper presents some theoretical and experimental aspects regarding the tribological performan... more The paper presents some theoretical and experimental aspects regarding the tribological performances of lead-free solder joint connections, with application in the aerospace domain. In order to highlight the mechanical and tribological properties of solder joint in correlation with different pad finishes, there were made some mechanical determinations using a dedicated Share Test System. The theoretical model highlights the link between the experimental results and the influence of gravitational acceleration on the mechanical and functional integrity of the electronic assemblies that works in vibration environment. The paper novelty is provided by the interdisciplinary experiment that offers results that can be used in the mechanical, tribological, electronical and aerospace domains.

The present paper was contoured having the purpose to determinate the effect of adhesion forces a... more The present paper was contoured having the purpose to determinate the effect of adhesion forces above the mechanical quality of the electronic solder joints. The analyze of the PIN PAD connection as a result of Vapour Phase Soldering (VPS) technology imply the identification of the specific factors of this technology that determinate the electrical, thermal and mechanical properties of the component elements as well the physic-chemical processes that take place at the connection forming. The practical testing of the mechanical function of the electronic connection was made with “Shear Test” multifunctional equipment that applies a maximum shear force of 400 N, with the possibility to identify the breaking force of the tested joint and images capture.

2015 IEEE 21st International Symposium for Design and Technology in Electronic Packaging (SIITME), 2015

In the context of globalization, taking into account the assembling line in electronic industry m... more In the context of globalization, taking into account the assembling line in electronic industry movements to the central and east European countries, the continuous production costs reduction tendency and the difficulties to accomplish both financials respectively technical aspects of the business, untypical situations could be encountered with consequence over production quality and reliability. In the paper typical assembling defects are presented and the causes analyzed relating to the real situations encountered on assembling lines. The matters determined by the distances between local branches or /and between them and mother company, the electronic components and materials transfercircuit and quality, the delay between the local assembling processes problems and technical decisions at the mother company level were considered. The wave contaminations aspects will be also analyzed. Some solutions will be proposed based on the analyses.

The paper describes an electronic multiprocessor system that assures functionality of a miniature... more The paper describes an electronic multiprocessor system that assures functionality of a miniature UAV capable of 3D flying. The apparatus consists of six independently controlled brushless DC motors, each having a propeller attached to it. Since the brushless motor requires complex algorithms in order to achieve maximum torque, efficiency and response time a DSP must be used. All the motors are then controlled by a main microprocessor which is capable of reading sensors (Inertial Measurement Unit (IMU)-orientation and GPS), receiving input commands (remote controller or trajectory plan) and sending independent commands to each of the six motors. The apparatus contains a total of eight microcontrollers: the main unit, the IMU mathematical processor and one microcontroller for each of the six brushless DC motors. Applications for such an apparatus could include not only military, but also search-and-rescue, geodetics, aerial photography and aerial assistance.

2015 7th International Conference on Electronics, Computers and Artificial Intelligence (ECAI), 2015

The subject of the present work is an irrigation controller able to satisfy the needs of a small ... more The subject of the present work is an irrigation controller able to satisfy the needs of a small farm for water, nutrients and pesticides having in view the consumption efficiency, as well as energy savings and cost effectiveness. In order to achieve these targets, the process is largely automated being a scheme with closed loop reaction based on the monitoring of several main parameters characterizing the soil and environment condition. The monitoring element is a multi-sensor device connected wirelessly to the central unit of the irrigation controller. For a small and medium size farm several devices are needed forming a wireless sensor network. The paper is focused on the peculiar solar supply of the wireless sensors network in order to exploit the data provided by the photovoltaic cell for a better management of the crops. Agronomists agree that crops needs are for a medium illuminance ranging from 20,000 to 50,000 lx, that corresponds to a shade illuminated by entire clear blue sky, midday. Therefore, the experiments were conducted mainly for establishing a threshold voltage for detecting 20,000 lx illuminance in order to count the days requested for proper harvesting.

Agriculture and Agricultural Science Procedia, 2015

The paper aimed to present the investigation of the use of photovoltaic cells based devices for s... more The paper aimed to present the investigation of the use of photovoltaic cells based devices for solar light measurements and analysis in order to forecast the pace of growth of plants and to estimate the appropriate timing of harvest culture. It is based on the continuous data measurements by a microcontroller based circuitry of a solar module used for supplying a multi-functional wireless sensor for agriculture. The solar module consists of two monocrystalline solar cells (c-Si) flat design, highly transparent and having UV stable front encapsulation. The data is not only a simple day and night information, but a measurement of the solar radiation. The device is able to measure the environment temperature as well, therefore the data is useful for evaluation of the photoperiodism, but the correlation between solar radiation and temperature is also possible. The data is transmitted to a host controller able to store and process higher volume information. As a conclusion, the research seeks to provide a low-cost solution for small and medium size farms based on the very solar cells used to supply low-power consumption electronic modules of the wireless network sensors for an optimal recovery of production depending on the type of culture.

Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies VII, 2015

ABSTRACT In this paper there are presented investigations regarding power IR LED efficiency in re... more ABSTRACT In this paper there are presented investigations regarding power IR LED efficiency in relation to operating temperature in order to define the reference values and conditions for using such devices for realizing long range proximity sensors, especially for applications in the automotive domain. The previous experiments done regarding the power LED used for infrared sources emphasize the optical power dependency to temperature. The new experiments were designed for measuring optical power and temperatures of LED heat sink and case, respectively of star and square type circuit boards (thermally conductive insulated metal substrate - IMS), at different points in the same time, for different values of LED driving current and various ambient temperatures, in order to make a correlation between LED efficiency and temperature. The results obtained and presented in this paper will be used further as references for designing an anticollision warning system with applications into automotive domain.

2013 IEEE 19th International Symposium for Design and Technology in Electronic Packaging (SIITME), 2013

The solder joints properties are determined by the specific morphology of their microstructure. I... more The solder joints properties are determined by the specific morphology of their microstructure. In the paper are presented the comparative resistance measurements of the solder joints resulted by usage of lead/lead-free solder pastes from Vapor Phase Soldering Processes (VPS) having thermal profile with two different cooling rate, slow one (0.5 K/s) and rapid one (4 K/s). The results will be promote to develop the practical applications of this soldering technology and to contribute at realization of a data base useful for better selection of lead-free solder paste in the design and manufacturing area.

2010 IEEE 16th International Symposium for Design and Technology in Electronic Packaging (SIITME), 2010

ABSTRACT

Proceedings of the 2014 37th International Spring Seminar on Electronics Technology, 2014

It is an actual trend for electronic equipment to be used into growing range of working temperatu... more It is an actual trend for electronic equipment to be used into growing range of working temperatures and at high level of the mechanical stress. As example, for the domains exempted by RoHS 2 EU Directive (it became law from January 2013) like aerospace, the standard maximum working temperature is 398.15K (125°C). The results of the comparative investigations regarding electrical and mechanical properties of the Lead/Lead-free solder joints function of working temperature and soldering thermal profile are presented in the paper. The experiments were designed based on previous work [1,2] having as starting point the “Homologous Temperature” concept [1,3,4], in order to respond to constrains imposed by the qualification processes of lead-free solder alloys for usage into exempted domains according to the RoHS 2 EU Directive [5,6].

Advanced Topics in Optoelectronics, Microelectronics, and Nanotechnologies VI, 2012

ABSTRACT The solar panels (SP) are the main energy source especially for the new generation of na... more ABSTRACT The solar panels (SP) are the main energy source especially for the new generation of nanosatelit. Having an area of around 100mm2, SP are obtained by soldering photovoltaic (PV) cells on the surface of a dedicated printed circuit board (PCB). The power and voltage values generated have been obtained by the interconnection structures of PV cells used to realize SP. The soldering process could be manually or reflow type, when are used surface mounted technologies (SMT). The process constrains are generated by the PV cells’ structure and materials. In this paper the authors proposed vapor phase soldering (VPS) technology for assembling PV cells based on germanium, having maximum 0.5mm thickness, in order to avoid the mechanical damages which appear in the manual soldering process and to provide uniform heating with the peak temperature less than 150ºC. The novelty of the proposal consists in realizing the control of VPS process in order to obtain a precise and repeatable thermal profile (TP) below VPS liquid boiling point. Based on the experiments already done, theoretical studies and experiments regarding the heat transfer in VPS process there will be developed, in order to define a technology for assembling SP module with PV cells soldered into one step.

2009 15th International Symposium for Design and Technology of Electronics Packages (SIITME), 2009

The objective of this paper is to present the strategic project ¿Promoting the entrepreneurial sp... more The objective of this paper is to present the strategic project ¿Promoting the entrepreneurial spirit within the Romanian electronics industry¿, co-financed by European Social Fund (ESF). Its main objective is to promote entrepreneurship in Romanian electronics industry, the electronics packaging education, and technological transfer, to offer technological and technical support for innovative SMEs, in order to compensate the small entrepreneurs