Visual Inspection Algorithms for Printed Circuit Board Patterns A SURVEY

The importance of the inspection process has been magnified by the requirements of the modern manufacturing environment. In electronics mass-production manufacturing facilities, an attempt is often made to achieve 100 % quality assurance of all parts, subassemblies, and finished goods. A variety of approaches for automated visual inspection of printed circuits have been reported over the last two decades. In this survey, algorithms and techniques for the automated inspection of printed circuit boards are examined. A classification tree for these algorithms is presented and the algorithms are grouped according to this classification. This survey concentrates mainly on image analysis and fault detection strategies, these also include the state-of-the-art techniques. Finally, limitations of current inspection systems are summarized

Knowledge composition methodology for effective analysis problem formulation in simulation-based design

In simulation-based design, a key challenge is to formulate and solve analysis problems efficiently to evaluate a large variety of design alternatives. The solution of analysis problems has benefited from advancements in commercial off-the-shelf math solvers and computational capabilities. However, the formulation of analysis problems is often a costly and laborious process. Traditional simulation templates used for representing analysis problems are typically brittle with respect to variations in artifact topology and the idealization decisions taken by analysts. These templates often require manual updates and "re-wiring" of the analysis knowledge embodied in them. This makes the use of traditional simulation templates ineffective for multi-disciplinary design and optimization problems. Based on these issues, this dissertation defines a special class of problems known as variable topology multi-body (VTMB) problems that characterizes the types of variations seen in design-analysis interoperability. This research thus primarily answers the following question: How can we improve the effectiveness of the analysis problem formulation process for VTMB problems? The knowledge composition methodology (KCM) presented in this dissertation answers this question by addressing the following research gaps: (1) the lack of formalization of the knowledge used by analysts in formulating simulation templates, and (2) the inability to leverage this knowledge to define model composition methods for formulating simulation templates. KCM overcomes these gaps by providing: (1) formal representation of analysis knowledge as modular, reusable, analyst-intelligible building blocks, (2) graph transformation-based methods to automatically compose simulation templates from these building blocks based on analyst idealization decisions, and (3) meta-models for representing advanced simulation templates VTMB design models, analysis models, and the idealization relationships between them. Applications of the KCM to thermo-mechanical analysis of multi-stratum printed wiring boards and multi-component chip packages demonstrate its effectiveness handling VTMB and idealization variations with significantly enhanced formulation efficiency (from several hours in existing methods to few minutes). In addition to enhancing the effectiveness of analysis problem formulation, KCM is envisioned to provide a foundational approach to model formulation for generalized variable topology problems.Ph.D.Committee Co-Chair: Dr. Christiaan J. J. Paredis; Committee Co-Chair: Dr. Russell S. Peak; Committee Member: Dr. Charles Eastman; Committee Member: Dr. David McDowell; Committee Member: Dr. David Rosen; Committee Member: Dr. Steven J. Fenve

Construction, test and commissioning of the triple-GEM tracking detector for COMPASS

The Small Area Tracking system of the COMPASS experiment at CERN includes a set of 20 large area, fast position-sensitive Gas Electron Multiplier (GEM) detectors, designed to reliably operate in the harsh radiation environment of the experiment. We describe in detail the design, choice of materials, assembly procedures and quality controls used to manufacture the devices. The test procedure in the laboratory, the performance in test beams and in the initial commissioning phase in the experiment are presented and discussed

Characterization of electronic board material properties under impact loaDing

On-board electronics in advanced military equipment are often subjected to severe ballistic shocks and vibrations. Impact and shock to such products can cause significant functional and physical damage. Safeguarding on-board electronic sensors from such transient shocks due to ballistic impact is of concern. While several studies document material characteristics of electronic boards under quasi-static and low impact conditions, few researchers addressed the behavior of these boards under severe impact loaDing This research presents the results of testing electronic boards under different strain rates to assess the effects of strain rates on modulus of elasticity of the boards. This work also outlines the finite element modeling methodology for these electronic components that are subjected to high acceleration loads that occur over extremely short time such as impact, gun firing and blast events. The results are used to suggest material models that can be used in finite element codes to accurately describe the impact behavior of these boards

AUTOMATIC OPTICAL INSPECTION-BASED PCB FAULT DETECTION USING IMAGE PROCESSING

Increased Printed Circuit Board (PCB) route complexity and density combined with the growing demand for low-scale rapid prototyping has increased the desire for Automated Optical Inspection (AOI) that reduces prototyping time and production costs by detecting defects early in the production process. Traditional defect detection method of human visual inspection is not only error prone but is also time-consuming given the growing complex and dense circuitry of modern-day electronics. Electric contact-based testing, either in the form of a bed of nails testing fixture or a flying probe system, is costly for low-rate rapid prototyping. An AOI is a non-contact test method using an image processing algorithm that quickly detects and reports failures within the PCB layer based on the captured image. A low-cost AOI system has been created using commercial off-the-shelf components specifically for low-rate production prototyping testing allowing testing of varying layers or various electronic designs without additional setup cost. Once the AOI system is physically configured, the image processing defect detection algorithm compares the test image with a defect-free reference image or by a set of pre-defined rules generated through Electronic Design and Analysis software. Detected defects are then classified into two main categories: fatal and potential. Fatal defects lead to the board\u27s rejection, while potential defects alert the operator to determine if the board should be rejected or will still satisfy pre-defined prototyping criteria. The specifications of an imaging system, camera sensor, imaging lens, and illumination set-up used in the creation of the AOI were designed considering a test PCB article already in production. The algorithm utilized is based on a non-reference defect detection method utilizing mathematical morphology-based image processing techniques to detect defects in the PCB under test

Autonomous Scale Car Using Computer Vision and Neural Networks

This report explores the feasibility of creating an autonomous 1:10 scale car capable of racing against RC cars on any indoor track. Custom made and equipped with a livestream sensor display module, the car leverages Artificial Neural Networks (ANN) to produce optimal driving outputs. Manipulating grayscale pixel input from a single, front-facing camera, the car navigates without the use of mapping or localization. Instead, the car relies on extensive training that allows the vehicle to adapt to variable conditions

Inspection of the integrity of surface mounted integrated circuits on a printed circuit board using vision

Machine vision technology has permeated many areas of industry, and automated inspection systems are playing increasingly important roles in many production processes. Electronic manufacturing is a good example of the integration of vision based feedback in manufacturing and the assembly of surface mount PCBs is typical of the technology involved. There are opportunities to use machine vision during different stages of the surface mount process. The problem in the inspection of solder joints on surface mount printed circuit board is much more difficult than many other inspection problems. In this thesis, an approach for inspecting surface mounted integrated circuits (SMICs) is presented. It is based on the variance of intensity values of pixels in an image. This method is able to cope with 4 kinds of soldering defects in SMICs. A set of modules for the system is proposed. The computer program which performs the image processing and analyzing has been written in C. It has been linked with a number of image processing routines from MAVIS1 to perform some image processing tasks, and the result is a compact executable module which works under MS-DOS2 3.30

Lab-on-PCB Devices

Lab-on-PCB devices can be considered an emerging technology. In fact, most of the contributions have been published during the last 5 years. It is mainly focussed on both biomedical and electronic applications. The book includes an interesting guide for using the different layers of the Printed Circuit Boards for developing new devices; guidelines for fabricating PCB-based electrochemical biosensors, and an overview of fluid manipulation devices fabricated using Printed Circuit Boards. In addition, current PCB-based devices are reported, and studies for several aspects of research and development of lab-on-PCB devices are described

Spring contact probes: wear characteristics testing for electrical and mechanical parameters

The study considers the development and evaluation of spring contact probes used for automated testing of printed circuit boards (PCBs) and assemblies. It considers the evolution of circuit technology which originated from the introduction of the thermionic valve at the beginning of the century. Since the introduction of the integrated circuit in the 1960's, the industry has seen considerable advances in integrated and printed circuit miniaturisation with its associated effect on the testability of the completed assembly. The close spacing between the tracks and pads within the printed circuit board, which is possibly loaded on both sides with integrated circuits and other components with fine pitch termination spacings, has initiated the rapid development of a specialised electronic test industry to ensure product quality. [Continues.

Capturing design process information and rationale to support knowledge-based design and analysis integration

Issued as final reportUnited States. Dept. of Commerc