Search Results for acoustic emission

This chapter discusses the types of sensors used in sheet forming operations and the information they provide. It explains how force sensors protect equipment from overloads due to tool wear, friction, and misfeeds, how displacement and proximity sensors help to prevent die crashes, how acoustic emission, ultrasonic, and eddy current sensors detect tool breakage and part defects such as cracks, and how roller ball and optical sensors measure material flow. It also discusses the role of draw-in, wrinkle, oil-monitoring, and vision sensors and explains how material properties can be derived in real time from various sensor outputs.

This chapter discusses the basic steps of a failure investigation. It explains that the first step is to gather and document information about the failed component and its operating history. It advises investigators to visit the failure site as soon as possible to record damages and collect test specimens for subsequent examination and chemical analysis. It also discusses the role of mechanical property testing, the use of nondestructive evaluation, and the final step of generating a report.

Welded joints in any component or structure require a thorough inspection. The role of nondestructive evaluation (NDE) in the inspection of welds is very important, and the technology has become highly developed as a result. This article describes the applications, methods, evaluation procedures, performance, and limitations of NDE. It provides information on the training and certification of NDE operators, evaluation of test results, and guidance to method selection. Typical examples of various NDE methods for welds are also described.

This chapter discusses the techniques applicable to the diagnosis of corrosion failures, including visual and microscopic examination of corroded surfaces and microstructure; chemical analysis of the metal, corrosion products, and bulk environment; nondestructive evaluation methods; corrosion testing techniques; and mechanical testing techniques. A guide to investigative techniques used in corrosion failure analysis is provided in a table, describing the advantages and limitations of each technique. The principal stages of the investigation and analysis of corrosion failures discussed in the chapter are: collection of background information and sampling; preliminary laboratory examination; detailed metallographic and fractographic examinations; chemical analysis of corrosion products and bulk materials; corrosion testing for quality control; mechanical testing for quality control; and analysis of results and report writing.

This chapter concentrates almost exclusively on inspection techniques related to pressure vessels and pipework. The discussion covers the general aspects associated with inspection and the key factors relevant to it. In addition, the chapter addresses processes involved in data collection and management, namely data acquisition, reporting, trending, reviewing, and auditing. Capabilities and limitations of in-service inspection techniques are discussed in the Appendix to this chapter.

In embedded systems, the separation between system level, board level, and individual component level failure analysis is slowly disappearing. In order to localize the initial defect area, prepare the sample for root cause analysis, and image the exact root cause, the overall functionality has to be maintained during the process. This leads to the requirement of adding additional techniques that help isolate and image defects that are buried deeply within the board structure. This article demonstrates an approach of advanced board level failure analysis by using several non-destructive localization techniques. The techniques considered for advanced fault isolation are magnetic current imaging for shorts and opens; infrared thermography for electrical shorts; time-domain-reflectometry for shorts and opens; scanning acoustic microscopy; and 2D/3D X-Ray microscopy. The individual methods and their operational principles are introduced along with case studies that will show the value of using them on board level defect analysis.

This chapters discusses the basic steps in the failure analysis process. It covers examination procedures, selection and preservation of fracture surfaces, macro and microfractography, metallographic analysis, mechanical testing, chemical analysis, and simulated service testing.

As semiconductor feature sizes have shrunk, the technology needed to encapsulate modern integrated circuits has expanded. Due to the various industry changes, package failure analyses are becoming much more challenging; a systematic approach is therefore critical. This article proposes a package failure analysis flow for analyzing open and short failures. The flow begins with a review of data on how the device failed and how it was processed. Next, non-destructive techniques are performed to document the condition of the as-received units. The techniques discussed are external optical inspection, X-ray inspection, scanning acoustic microscopy, infrared (IR) microscopy, and electrical verification. The article discusses various fault isolation techniques to tackle the wide array of failure signatures, namely IR lock-in thermography, magnetic current imaging, time domain reflectometry, and electro-optical terahertz pulse reflectometry. The final step is the step-by-step inspection and deprocessing stage that begins once the defect has been imaged.

The complexity of semiconductor chips and their packages has continuously challenged the known methods to analyze them. With larger laminates and the inclusion of multiple stacked die, methods to analyze modern semiconductor products are being pushed toward their limits to support these 2.5D and 3D packages. This article focuses on these methods of fault isolation, non-destructive imaging, and destructive techniques through an iterative process for failure analysis of complex packages.

This chapter describes nondestructive evaluation (NDE) test methods and their relative effectiveness for diagnosing the cause of stress-corrosion cracking (SCC) service failures. It discusses procedures for analyzing various types of damage in carbon and low-alloy steels, high-strength low-alloy steels, hardenable stainless steels, austenitic stainless steels, copper-base alloys, titanium and titanium alloys, aluminum and aluminum alloys, and nickel and nickel alloys. It identifies material-environment combinations where SCC is known to occur, provides guidelines on how to characterize cracking and fracture damage, and explains what to look for during macroscopic and microscopic examinations as well as chemical and metallographic analyses. It also includes nearly a dozen case studies investigating SCC failures in various materials.

Since the introduction of chip scale packages (CSPs) in the early 90s, they have continuously increased their market share due to their advantages of small form factor, cost effectiveness and PCB optimization. The reduced package size brings challenges in performing failure analysis. This article provides an overview of CSPs and their classification as well as their advantages and applications, and reveals some of the challenges in performing failure analysis on CSPs, particularly for CSPs in special package configurations such as stacked die multi-chip-packages (MCPs) and wafer level CSPs (WLCSPs). The discussion covers special requirements of CSPs such as precision decapsulation for fine ball grid array packages, accessing the failing die for MCP packages, and careful handling for WLCSP. Solutions and best practices are shared on how to overcome these challenges. The article also presents a few case studies to demonstrate how failure analysis work on CSPs can be successfully completed.

Failure analysis of steel welds may be divided into three categories. They include failures due to design deficiencies, weld-related defects usually found during inspection, and failures in field service. This chapter emphasizes the failures due to various discontinuities in the steel weldment. These include poor workmanship, a variety of hydrogen-assisted cracking failures, stress-corrosion cracking, fatigue, and solidification cracking in steel welds. Hydrogen-assisted cracking can appear in four common forms, namely underbead or delayed cracking, weld metal fisheyes, ferrite vein cracking, and hydrogen-assisted reduced ductility.

This chapter assesses the potential impact of neural networks on package-level failure analysis, the challenges presented by next-generation semiconductor packages, and the measures that can be taken to maximize FA equipment uptime and throughput. It presents examples showing how neural networks have been trained to detect and classify PCB defects, improve signal-to-noise ratios in SEM images, recognize wafer failure patterns, and predict failure modes. It explains how new packaging strategies, particularly stacking and disintegration, complicate fault isolation and evaluates the ability of various imaging methods to locate defects in die stacks. It also presents best practices for sample preparation, inspection, and navigation and offers suggestions for improving the reliability and service life of tools.

This chapter addresses in-service monitoring and corrosion testing of weldments. Three categories of corrosion monitoring are discussed: direct testing of coupons, electrochemical techniques, and nondestructive testing techniques. The majority of the test methods for evaluating corrosion of weldments are used to assess intergranular corrosion of stainless steels and high-nickel alloys. Other applicable tests evaluate pitting and crevice corrosion, stress-corrosion cracking, and microbiologically influenced corrosion. Each of these test methods is reviewed in this chapter.

Education and training play an important role if the failure analyst is to be successful in his or her work. This article discusses the history of training activities in the failure/product analysis discipline and describes where this area is heading. It provides information on three areas of education and training that should be given to the analyst for him or her to be successful developing and fielding modern semiconductor components: analysis process, technology, and technique training.

This chapter discusses the selection, use, and integration of methods to control process variables in induction heating, including control of workpiece and processing temperature and materials handling systems. The discussion of temperature control includes a review of proportional controllers and heat-regulating devices. Integration of control functions is illustrated with examples related to heating of steel slabs, surface hardening of steel parts, vacuum induction melting for casting operations, and process optimization for electric-demand control. Distributed control within larger manufacturing systems is discussed. The chapter also covers nondestructive techniques for process control and methods for process simulation.