Search Results for in-process monitoring

This article lists the system parameters of the friction welding process and describes the four categories of monitoring and control of the manufacturing process. It discusses the monitoring methods of a rotary friction welded sample, for determining in-process quality of ferrous alloys, and dissimilar metals using acoustic emission. The article reviews the feasibility of detecting the presence of ferrite during microstructural evolution of friction welding of three austenitic stainless steels: 310, 304, and 255. It also explains the in-process quality control of friction welding.

This article covers in-line process monitoring of the metal additive manufacturing (AM) methods of laser and electron beam (e-beam) powder-bed fusion (PBF) and directed-energy deposition (DED). It focuses on methods that monitor the component directly throughout the build process. This article is organized by the type of AM process and by the physics of the monitoring method. The discussion covers two types of monitoring possible with the PBF process: monitoring the area of the powder bed and component and monitoring the melt pool created by the laser or e-beam. Methods for layer monitoring include optical and thermal methods that monitor light reflected or emitted in the visible and infrared wavelengths, respectively. Monitoring methods for laser directed-energy deposition (DED) discussed are those that measure the size and shape of the melt pool, the temperature of the melt pool, and the plasma generated by the laser as it interacts with the molten metal.

In situ process monitoring includes any technologies that monitor or inspect during an additive manufacturing (AM) process. This article presents the types, process considerations, and challenges of in situ monitoring technologies that can be implemented during an AM process. The types include system health monitoring, melt pool monitoring, and layer monitoring. The article discusses data analysis, and provides an overview of the integration of sensors into AM machines.

The basic elements of control design are safety, process control, process verification, machine control, productivity, repeatability, and ease of setup. Effective systems of quality control/quality assurance are essential for heat treating practices. This article provides information on process control modes, as well as on process signatures of some items that require control, monitoring, verifying, and logging methods. It provides information on programmable logic controllers that have become efficient in machine control and monitoring. The article describes possible noise issues, National Electric Code clearance requirements, monitoring requirements, and machine accuracy that need to be considered when designing induction equipment.

The use of additive manufacturing (AM) is increasing for high-value, critical applications across a range of disparate industries. This article presents a discussion of high-valued engineering components predominantly used in the aerospace and medical industries. Applications involving metal AM, including methods to identify pores and voids in AM materials, are the focus. The article reviews flaw formation in laser-based powder-bed fusion, summarizes sensors used for in situ process monitoring, and outlines advances made with in situ process-monitoring data to detect AM process flaws. It reviews investigations of ML-based strategies, identifies challenges and research opportunities, and presents strategies for assessing anomaly detection performance.

Additive manufacturing (AM) is a revolutionary technology that fabricates parts layerwise and provides many advantages. This article discusses polymer AM processes such as material extrusion, vat photopolymerization (VPP), powder-bed fusion (PBF), binder jetting (BJ), material jetting (MJ), and sheet lamination (SL). It presents the benefits of online monitoring and process control for polymer AM. It also introduces the respective monitoring devices used, including the models and algorithms designed for polymer AM online monitoring and control.

This article describes the criteria for selecting a corrosion-monitoring method used in industrial plants. It provides a detailed discussion on the design, advantages, and disadvantages of plant corrosion-testing program. The basic types of racks used to support and insulate the coupons are also discussed. The analysis of electrical-resistance probes, sentry holes, side-stream loop, electrochemical noise, hydrogen-probe, and process streams are used to monitor and estimate corrosion rates. The corrosion rates can also be estimated by ultrasonic thickness measurements, polarization-resistance measurements, corrosion potential measurements, and alternating current impedance measurements. Corrosion monitoring strategies, such as locations, data analysis, redundancy, and other issues, are discussed. The article concludes with information on the interpretation and reporting of corrosion testing.

Vibroacoustic analysis of mechanical systems has an important role in the engineering discipline. This can be used as a monitoring tool to obtain insights about the condition of a system, identify its probable defects, and determine the time window that the maintenance should happen. This article introduces the basics of signal processing in time, frequency, and time-frequency domains. It focuses on statistical analysis of the time-domain data. Various measures of data distribution and variability are pointed out. Important signal-processing functions in the frequency domain are presented and explained with examples. The article discusses and clarifies the benefits of time-frequency domain based on short-time Fourier transform with some practical applications. The article presents the most frequently used statistical functions. It concludes with information on some real-world applications of vibroacoustic analysis.

This article reviews weld quality monitoring considerations for two automotive materials, steel and aluminum, with a focus on photosensor technology. It provides an overview of the process description, process parameters, and weld characteristics of laser welding. The article discusses real-time or in-process monitoring, which is done with optical, acoustic, and/or charged-particle sensors. It highlights the advantages, applications, and selection criteria of weld monitoring system and concludes with examples of laser weld monitoring in the production of tailor-welded blanks.