Search Results for planning stages

This article describes the test methods for evaluating the durability of a metal in soil. It provides useful information on soil characteristics such as soil electrical resistivity, pH value, and soil texture. Specimen design, preparation, burial, and retrieval techniques are discussed. The type of information sought during soil-induced corrosion evaluation controls the design configuration and the nature of the corrosion measurements. Consideration of these factors during the planning stage helps the corrosion engineer to obtain the maximum amount of information with the minimum number of problems.

Failure analysis is a process that is performed in order to determine the causes or factors that have led to an undesired loss of functionality. This article is intended to demonstrate proper approaches to failure analysis work. The goal of the proper approach is to allow the most useful and relevant information to be obtained. The discussion covers the principles and approaches in failure analysis work, objectives and scopes of failure analysis, the planning stages for failure analysis, the preparation of a protocol for a failure analysis, practices used by failure analysts, and procedures of failure analysis.

As additive manufacturing (AM) gains maturity as a manufacturing technique for production in many industrial sectors, inspection as a tool for quality control gains importance. This article is focused on the field of dimensional metrology, which is typically concerned with the verification of size, location, form, and surface topography of geometric features. This is split into two categories: geometric (size, location, form) and surface measurement (topography). The article also focuses on applicable inspection technologies, and it discusses the context within digital thread manufacturing. A case study on the Digital Inspection Requirements Enhancing Coverage and Traceability (DIRECT) is also presented.

The basic quality analysis tools are cause-and-effect diagrams, check sheets, control charts, histograms, Pareto charts, scatter diagrams, and run charts. This article reviews how basic quality analysis tools are built upon to become a more advanced set of quality tools. It describes the advanced quality tools: advanced product quality planning, failure mode and effects analysis, control planning, measurement systems analysis, lean tools, statistical process control, production viability and tryout, and Six Sigma.

The distinction between an unconfined web and a confined web describes the relative ease of flow of metal to flash during forging. This article describes the various types of unconfined and confined web-and-rib combinations encountered in the design of forgings. It informs that the limits suggested by forging producers and users covering minimum web thicknesses that are producible are helpful in estimating the producibility of a given web thickness in projected-forging design. The article briefly analyzes the web designs of several forgings, including designs for producing flat webs, contoured webs, and oblique webs. It provides a checklist to be reviewed by a web designer.

When planning a corrosion-testing program, it is advisable to select the testing conditions carefully in order to produce ranking parameters with minimal influence from testing conditions while rich in engineering significance. This article provides a discussion on test objectives, metal composition and metallurgical conditions, test specimen preparation, and corrosion damage assessment. It describes a strategy for planning the design of controlled and uncontrolled factorial experiments. The article contains a table that lists the elements of an iterative process for the experimental design. It illustrates the experimental designs applied to corrosion testing.

Additive manufacturing (AM), or three-dimensional (3D) printing, is a class of manufacturing processes that create the desired geometries of an object, or an assembly of objects, layer by layer or volumetrically. AM has been used extensively for manufacturing medical devices, due to its versatility to satisfy the specific needs of an intended medical field for the product/device. This article provides a comprehensive review of AM in medical devices by the medical specialty panels of the Food and Drug Administration (FDA) Code of Federal Regulations, Parts 862 to 892, including anesthesiology, ear and nose, general hospital, ophthalmic, plastic surgery, radiology, cardiovascular, orthopedic, dental, neurology, gynecology, obstetrics, physical medicine, urology, toxicology, and pathology. It is classified under these panels, and critical reviews and future outlooks are provided. The application of AM to fabricate medical devices in each panel is reviewed; lastly, a comparison is provided to reveal relevant gaps in each medical field.

Planning of experiments does not consist merely of identifying a few key parameters and then selecting a specific plan. Selection of the proper experimental plan depends on the purpose of the experiment, physical restrictions on the taking of measurements, and other restrictions imposed by time, economic considerations, and materials and personnel availability. This article presents recommendations that should be followed in outlining the methods of conducting and analyzing an experiment to ensure successful results. It discusses restricted type of experiments, in which the experimenter varies the parameters, or factors, under study and then observes the effects of this action. These include factorial experiments, blocked factorial experiments, and fractional factorial experiments. The article describes the estimation of experimental errors and provides information on randomized designs and block designs. It also presents the methods for determining optimum conditions or levels.

A test plan specifies material properties to be evaluated, selects test methods, eliminates options offered by standard test methods by selecting specific specimen and test configurations, and defines success criteria. This article discusses various testing objectives that affect the execution of testing programs. The testing objectives include development of test matrices, testing standards, specimen preparation, environmental conditioning, instrumentation and data acquisition, failure modes, and data interpretation and recording.

The introduction of focused ion beam (FIB) microscopy in the 1990s added the capability of studying fracture surfaces in the third dimension and making site-specific and stress-free transmission electron microscope (TEM) specimens in situ. This article reviews the methods for preparing replicas and the site-specific FIB thin-foil preparation technique. It provides an overview of FIB-TEM specimen preparation.

This article describes the four basic steps of the purchasing process of cast components. These steps include defining requirements and developing a purchasing plan; requesting and evaluating bids from potential sources; selecting a source and negotiating contract terms; and carrying out the contract and pursuing continuous improvement. It provides guidance on purchasing cast components and explains specific issues and approaches that have proven to be useful in purchasing castings. The article presents a list of the most significant considerations when attempting to determine the overall cost and design requirements of a metal casting.

Machining or material removal processes are secondary manufacturing operations that are used to achieve precise tolerances or to impart controlled surface finishes to a part. This article summarizes rules for designing parts to improve machined part quality and reduce machining costs in mass and batch production environments. It discusses the factors affecting the total cost of a machining operation, including raw material costs, labor costs, and equipment costs. The article describes three types of machining systems, namely, general-purpose machine tools, production machining systems, and computer numerically controlled (CNC) machining systems. It reviews general design-for-machining rules that are applicable to all parts, regardless of the type of equipment used to produce them. Special considerations for production machining systems and CNC machining systems are discussed. The article describes the structure and typical uses of computer-aided process planning and design-for-manufacturing programs.

Precision forging is defined as a closed-die forging process in which the accuracy of the shape, dimensional tolerances, and surface finish exceed normal expectations to the extent that some of the postforge operations can be eliminated. This article provides an overview of the key factors that impact the precision forging process. It provides information on the achievable tolerances and presents examples of precision forging. A discussion on forging of bevel gears/spiral bevel gears is also presented.

This article provides a summary of the conventional technologies used for titanium powder production. It focuses on the various processes for titanium powder production, namely, Hunter, Kroll, Armstrong, MER, TIRO, FFC-Cambridge, Chinuka, and CSIR processes. Employment of titanium powder significantly improves the synthesis of titanium and its alloys.

Fracture control is a systematic process to prevent fracture during operation that depends on the criticality of the component, the economic consequences of the structures being out of service, and the damage that would be caused by a fracture failure. This article describes the key principles of fracture control and reviews the concepts of damage tolerance analysis. It further presents practical guidelines to obtain useful and reasonable answers from damage tolerance analysis. The article concludes with information on fracture mechanics and fatigue design.

This article addresses problems, such as “in spec” dilemma and on-target key, associated with traditional approaches to quality. It discusses major robust design techniques, tools, and concepts, such as quality loss function, parameter design, tolerance design, signal-to-noise ratio, technology development, and orthogonal arrays.

This article focuses on the aspects associated with inspection related to pressure vessels and pipework. These aspects include inspection policy, inspection planning and procedures, inspection strategy, inspection methodology, preparation for inspection, invasive inspection, internal visual inspection, and non-invasive inspection. Inspection execution, risk-based inspection, competence assurance of inspection personnel, inspection coverage, inspection periodicity, inspection anomaly criteria, assessment of fitness, and reporting requirements, are also discussed. The article addresses the data acquisition, reporting and trending, and review and audit for the inspection. It reviews inspection techniques, including visual inspection, ultrasonic inspection, and radiographic inspection.

The chemicals that have been used in traditional vapor degreasing have serious health and environmental hazards that have prompted the search for modified and alternative techniques. This article provides a detailed discussion on the regulatory mandates that affect the use of industrial degreasing methods. It describes the aqueous degreasing technique, which forms an attractive alternative to the traditional vapor degreasing process. The article includes information on the materials and equipment used in the process, and discusses the advantages and disadvantages of hot and dip tank systems of aqueous degreasing. It explains how to convert an existing vapor degreaser to an aqueous cleaning system.

This article primarily considers the problem of sampling bulk materials, including minerals, metals, environmentally important substances, and industrial raw materials and waste products. It provides useful information on sample types, sampling plan, optimizing sampling resources, practical aspects of sampling, and how to ensure the quality of sampling.