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The assembly of printed circuit boards: A case with multiple machines and multiple board types

The assembly of printed circuit boards: A case with multiple machines and multiple board types

Abstract In this paper a typical situation arising in the assembly of printed circuit boards is investi- gated. The planning problem we face is how to assemble boards of di erent types using a single line of placement machines. From a practical viewpoint, the multiplicity of board types adds signi cantly to the complexity of the problem, which is already very hard to solve in the case of a single board type. In addition, relatively few studies deal with the multiple board type case. We propose a solution procedure based on a hierarchical decomposition of the planning problem. An important subproblem in this decomposition is the so-called feeder rack assignment problem. By taking into account as much as possible the individual board type characteristics (as well as the machine characteristics) we heuristically solve this problem. The remaining subproblems are solved using constructive heuristics and local search methods. The solution procedure is tested on real-life instances. It turns out that, in terms of the makespan, we can substantially improve the current solutions.
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Effects of operational parameters on the bio-assisted leaching of metals from pyrolyzed printed circuit boards

Effects of operational parameters on the bio-assisted leaching of metals from pyrolyzed printed circuit boards

Recycling Bio-leaching A B S T R A C T End-of-life printed circuit boards have been subjected to proprietary pyrolysis resulting in a copper-rich char containing liberated metals. For downstream processing and copper recovery, the char was exposed to two di fferent leaching solutions: one containing mixed microbial consortia originating from bioleaching of coal spoils and a cell-free chemical solution for comparative purpose. The in fluence of char pre-treatment, reactor type, temperature and type of leaching solution on the dissolution of the zero-valent copper was studied. It was found out, that for bringing copper in solution, the type of leaching solution had less pronounced e ffect than the type of reactor. Other than ferric iron concentration and temperature, the bacterial presence has shown e ffect on copper leaching kinetics and process efficiency. The fact that copper was continuously dissolved by ferric iron at initial concentrations well below the stoichiometric required ratio, demonstrated microbial regeneration of ferric iron and its back-cycling in the system. In case of the absence of microbe, the regeneration of ferric iron is driven by oxidation in the presence of O 2 and H + . A simplified kinetic model of copper dissolution suggested that the
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Characterization of printed circuit boards waste -influence of sample mass and particle size -example of zinc and nickel content

Characterization of printed circuit boards waste -influence of sample mass and particle size -example of zinc and nickel content

CHARACTERIZATION OF PRINTED CIRCUIT BOARDS WASTE – INFLUENCE OF SAMPLE MASS AND PARTICLE SIZE – EXAMPLE OF ZINC AND NICKEL CONTENT S. TOUZE 1 ,S. CHAPRON 1 , A. HUBAU 1 , S. GUIGNOT 1 1 BRGM, 3 av. Claude Guillemin, 45060 Orléans, France .

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Design and Analysis of Printed Circuit Boards Using FDTD Method for The 20-H Rule

Design and Analysis of Printed Circuit Boards Using FDTD Method for The 20-H Rule

Abstract--With the increasing demand of higher operating frequencies for electronic circuits, the printed circuit board designers face more electromagnetic radiation problems than ever. Some “rules-of-thumb” are employed to help the designers to reduce the radiation problems. The 20H rule is one of printed circuit design rules, which intends to minimize the electromagnetic radiation. This project focuses on analysis and simulation of 20H rule’s signal propagation mechanisms. The model used in the project is a 2D planar structure. The numerical electromagnetic method, Finite Difference Time Domain (FDTD) method, is used for the field computation and analysis. Simulation is based on various structures of model and different distributions of excitation sources. Analysis focuses on the signal propagation models. Field distributions and radiation patterns are visualized by mathematical software. Meanwhile, Poynting vectors are calculated to give quantitative expression. The simulation results indicate three factors, namely, operating frequency, size of PCB and separation distance that will affect the function of 20H rule. The effects of three factors are shown by comparison of specific cases in this thesis.
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Creation, validation, and implementation of a Highly Accelerated Life Testing (HALT) procedure to improve the reliability of printed circuit boards

Creation, validation, and implementation of a Highly Accelerated Life Testing (HALT) procedure to improve the reliability of printed circuit boards

Accelerated Life testing was done on the Acquity PCB using the standard operating procedure by subjecting it to thermal and vibration stresses through Hot Step Stress profil[r]

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The component retrieval problem in printed circuit board assembly

The component retrieval problem in printed circuit board assembly

1 Introduction The problem of determining optimal production plans for the automated assembly of printed circuit boards (PCBs) has been investigated by numerous researchers; see e.g. Ahmadi (1993) and Crama, Oerlemans and Spieksma (1994). A precise de nition of this problem is highly dependent on the speci c features of the assembly machines and, more generally, of the technological environment. As a rule, however, the problem is a very complex one and, for this reason, many authors have proposed to solve it by decomposing it into subproblems; see e.g. Ahmadi (1993), Ball and Magazine (1988), Bard, Clayton and Feo (1994), Crama, Flippo, van de Klundert and Spieksma (1995), Crama, Oerlemans and Spieksma (1994) and van Laarhoven and Zijm (1993). Here again, the subproblems emerging from the decomposition vary according to the context, as do their computational complexity. In this paper, we concentrate on one such subproblem, namely the Component Retrieval Problem (CRP) that arises when the placement machine operates like a machine of the Fuji CP family. Brie y stated, CRP is de ned to be the following problem: for a given placement sequence of components on the board, and for a given assignment of component types to (possibly multiple) feeder slots of the placement machine, decide from which feeder slot each component should be retrieved.
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An electrochemical approach to total organic carbon control in printed circuit board copper sulfate plating baths Part II: Overfall system

An electrochemical approach to total organic carbon control in printed circuit board copper sulfate plating baths Part II: Overfall system

1. Introduction In Part I it was shown that electrochemical oxidation could be used to remove problem organic contaminants from printed circuit board (PCB) plating baths [1]. The plating baths initially contain copper sulfate and sulfuric acid, as well as organic additives (typically levellers, brighteners and wetting agents) designed to improve the quality and speed of the electroplating. During the course of plating, fresh additives are added to make-up for those consumed by incorporation into the copper plate and by decomposition reactions (with air, and at the anode). Over time, the decomposed additives will build-up in the plating bath. Other causes of contami- nation include: organic compounds leached from the printed circuit boards and in particular their photoresist, contaminants carried in on the surfaces of the boards from previous process steps (‘drag in’), and airborne contaminants. This slow build-up of organic contami- nation can be followed by monitoring the plating bath total organic carbon (TOC). When problem TOC values are reached, the normal procedure is to treat the plating solution by contacting it with activated carbon, which acts to adsorbthe contaminants. After such a treatment, the additive concentrations are readjusted and plating can continue (at some operations the solution may also be filtered to remove carbon particle fines). Because of the carbon high surface area and high porosity, the used
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A Bidirectional Communicating Power Supply circuit for Smart Gate Driver boards

A Bidirectional Communicating Power Supply circuit for Smart Gate Driver boards

IV. D ISCUSSION AND PERSPECTIVES As mentioned in the introduction, the targeted application is health monitoring for power SiC MOSFET transistors. In this case, the RxD data are monitoring parameters that can be measured using the secondary circuit of a smart driver board such as the on-state voltage, the gate leakage currents, temperature values or others ageing indicators… The RxD data could also be used for fault transmission by sending a more detailed error message to the primary side. It could even replace the traditional error pulse transmission but this solution is not recommended as the latency of the proposed communication method is not guaranteed. Another application is the reparametrizing of the gate driver in real time which could be achieved by exploiting the TxD flux. For example, switching slope control, blanking time setting or gate-source voltage variation could be realized using the proposed method. Other
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Circuit Theory

Circuit Theory

The object of the present study is to devise a criterion for optimizing a parametric amplifier that consists of a time-dependent reactive element in an environment[r]

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Testing of Type "X" Gypsum Boards and Laths

Testing of Type "X" Gypsum Boards and Laths

To eliITlinate the possibility of basing a conclusion on some odd result, it is recommended that a gypSUITl board product be qualified as a type "X" product only if at least two [r]

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Theoritical and experimental study of magnetic sensors for near-field emission measurement. Application to design and integration in power printed board circuit

Theoritical and experimental study of magnetic sensors for near-field emission measurement. Application to design and integration in power printed board circuit

Near-Field (NF) techniques enable the development of non- intrusive sensors with high temporal and spatial resolution [2]. The electric field measurement is ensured by monopole and dipole probes whereas loop probes are used for magnetic field measurement [3]. In most applications, these sensors are associated with an external motorized arm to scan step after step the top surface of the Device Under Test (DUT). That gives access to electromagnetic (EM) cartography. Indeed, the localization of EM radiation sources and the DUT currents estimation is performed [4]. The sensor efficiency depends on probe size, area of the DUT and on the resolution step of the scanning system. However, the main drawback of NF scanning technique is the time consumption to collect all the samples, especially in Power Printed Circuit Board (PPCB) and Hybrid 3D structures. Due to their large size and to the 3D top surface, the scanning step and time characterization of such measurement systems does not allow an “in situ” and real time measurements
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Theoritical and experimental study of magnetic sensors for near-field emission measurement. Application to design and integration in power printed board circuit

Theoritical and experimental study of magnetic sensors for near-field emission measurement. Application to design and integration in power printed board circuit

Near-Field (NF) techniques enable the development of non- intrusive sensors with high temporal and spatial resolution [2]. The electric field measurement is ensured by monopole and dipole probes whereas loop probes are used for magnetic field measurement [3]. In most applications, these sensors are associated with an external motorized arm to scan step after step the top surface of the Device Under Test (DUT). That gives access to electromagnetic (EM) cartography. Indeed, the localization of EM radiation sources and the DUT currents estimation is performed [4]. The sensor efficiency depends on probe size, area of the DUT and on the resolution step of the scanning system. However, the main drawback of NF scanning technique is the time consumption to collect all the samples, especially in Power Printed Circuit Board (PPCB) and Hybrid 3D structures. Due to their large size and to the 3D top surface, the scanning step and time characterization of such measurement systems does not allow an “in situ” and real time measurements
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D-Le court circuit

D-Le court circuit

II Danger d’un court-circuit : 1) Risque d’incendie : Manip prof Observations : Lorsque l’on branche un fil de connexion aux bornes d’une lampe dans un montage en dérivation, les deux lampes s’éteignent et la paille de fer brûle.

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Circuit Theory

Circuit Theory

eters, the series resistance, the input power, and the harmonic number, realiza- bility of the condition of optimal operation can best be investigated by an analys[r]

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Circuit Theory

Circuit Theory

The advantage of treating lossless elements as components distinctly sep- arate from the interconnection network is that in this case analysis may be performed at [r]

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Circuit Theory

Circuit Theory

If we attempt to build a power amplifier utilizing a particular amplifying device and arbitrary passive coupling it is of interest to determine how the device cha[r]

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Circuit Theory

Circuit Theory

It will be presented in Quarterly Progress Report No.[r]

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Experimental investigation of the reliability of Printed Circuit Board (PCB)-embedded power dies with pressed contact made of metal foam

Experimental investigation of the reliability of Printed Circuit Board (PCB)-embedded power dies with pressed contact made of metal foam

In [18], we proposed a new technique to connect the top-side of a die, using a pressed contact made of metal foam. This paper deals with the reliability and the robustness of this process. Various sources of stress were experimentally investigated: samples were thermally cycled, submitted to current surges and submitted to short-circuit tests. These tests were intended, depending upon the nature of the stress applied, either to assess the reliability and robustness of the connection itself, or to ensure that the proposed packaging process does not degrade the reliability and robustness of the die. Few samples were submitted to each test, hence the limited statistical significance.
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Circuit Theory

Circuit Theory

A different type of reading machine is the "direct-translating" machine, in which no attempt is made to have the machine make the character identification, [r]

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Circuit Theory

Circuit Theory

Current short-range projects include work on parametric amplifiers, devices for nonlinear filtering, general network topology, instrumentation relating to aids to the [r]

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