Search results for "ray"
showing 10 items of 8009 documents
Ultrasonic phased array inspection of a Wire + Arc Additive Manufactured (WAAM) sample with intentionally embedded defects
2019
In this study, Wire + Arc Additive Manufacture (WAAM) was employed to manufacture a steel specimen with intentionally embedded defects which were subsequently used for calibration of an ultrasonic phased array system and defect sizing. An ABB robot was combined with the Cold Metal Transfer (CMT) Gas Metal Arc (GMA) process to deposit 20 layers of mild steel. Tungsten-carbide balls (ø1-3 mm) were intentionally embedded inside the additive structure after the 4th, 8th, 12th and 18th layers to serve as ultrasonic reflectors, simulating defects within the WAAM sample. An ultrasonic phased array system, consisting of a 5 MHz 64 Element phased array transducer, was used to inspect the WAAM sample…
Robotic geometric and volumetric inspection of high value and large scale aircraft wings
2019
Increased demands in performance and production rates require a radical new approach to the design and manufacturing of aircraft wings. Performance of modern robotic manipulators has enabled research and development of fast automated non-destructive testing (NDT) systems for complex geometries. This paper presents recent outcomes of work aimed at removing the bottleneck due to data acquisition rates, to fully exploit the scanning speed of modern 6-DoF manipulators. The geometric assessment of the parts is carried out with a robotised dynamic laser scanner encoded through an absolute laser tracker. This method allows scanning speeds up to 330mm/s at 1mm pitch. State of the art ultrasonic ins…
Comparison of electropolishing behaviours of TSC, ALM and cast 316L stainless steel in H 3 PO 4 /H 2 SO 4
2017
Abstract In recent decades, new manufacturing processes have been developed such as Thermal Spray Coating (TSC) and Additive Layer Manufacturing (ALM), which reduce or avoid machining of parts with complex geometries. This study aims to develop an Electropolishing (EP) process for TSC and ALM 316L Stainless Steel (SS). EP is an anodic dissolution process currently used in industry to reduce surface roughness and obtain a bright and smooth finish. The EP mechanism was studied, in a mixture of H3PO4 and H2SO4, for TSC, ALM and “cast” SS in order to determine the best conditions (time, temperature, potential). Special attention was paid to surface characterization by combining several techniqu…
Residual stress measurement in innovative friction stir welding processes
2017
In recent years, important innovations have been introduced in Friction Stir Welding (FSW) technology such as, for example, the Laser assisted Friction Stir Welding (LFSW) and in-process Cooled Friction Stir Welding (CFSW). Residual stresses have a fundamental role in welded structures because they affect the way to design the structures, fatigue life, corrosion resistance and many other material properties. Consequently, it is important to investigate the residual stress distribution in FSW where, though the heat input is lower compared to traditional welding techniques, the constraints applied to the parts to weld are more severe. The aim of the present work is to verify the capabilities …
A new approach to simulate coating thickness in cold spray
2020
Abstract In the process of cold spray on complex components, the coating thickness is an important indicator to monitor and control. Current methods such as destructive tests or direct mechanical measurements can only be performed after spraying. Besides, these methods lead to production shutdown and additional costs . This article presents a novel approach predicting coating thickness for components with complex curved surfaces, especially in the case of shadow effects. Firstly, a three-dimensional geometric model of the coating profile based on Gaussian distribution was developed. In addition, the relative deposition efficiency (RDE) resulting from the different robot kinematic parameters…
High-temperature in-process inspection followed by 96-h robotic inspection of intentionally manufactured hydrogen crack in multi-pass robotic welding
2021
Abstract This investigation introduces two new techniques to quantitatively address the challenging problem of understanding Hydrogen Induced Cracking (HIC) in welding processes. The first technique is a novel procedure to create a known and controlled HIC in a welded sample. The second is an in-process monitoring technique to measure the initial formation and subsequent growth of the HIC in a multi-pass weld whilst being compatible with the high temperatures associated with the welding process. The HIC was initiated using a localised quenching method of the weld and its character was verified using both macrograph and microscopic investigations. During HIC initiation and growth, the sample…
Direct laser welding of pure titanium to austenitic stainless steel
2018
Abstract Direct butt joining of pure titanium to 316L stainless steel with continuous Yb:YAG laser was performed with variation of the beam offset from joint line. Mechanical properties of samples were evaluated by tensile tests and three-point flexural tests. The fractured surfaces and cross sections of welds were examined by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Tensile properties of welds were strongly determined by the beam offset from joint line and are well described by Weibull statistics. Ultimate tensile strength of 174 ± 69 MPa and ultimate flexural strength of 297 ± 48 MPa were obtained. Brittle fracture took place in…
Stable layer-building strategy to enhance cold-spray-based additive manufacturing
2020
Abstract Cold spray (CS) has recently become one of the popular additive manufacturing (AM) processes for its advantages: high-forming efficiency, low temperature, and no phase changing of materials. These advantages may make CS able to form large volume objects and possibly directly iterate with material-removing processes to become a hybrid AM process. Current research proposes using a bulk-based volume-forming strategy (e.g. a tessellation-based method) for volume building. Although it can form 3D volumes, the control of the process is difficult and it has limitations in forming complex 3D near-net-shapes with acceptable accuracy. This also conflicts with the basic principle of AM, where…
Food tray sealing fault detection using hyperspectral imaging and PCANet
2020
Abstract Food trays are very common in shops and supermarkets. Fresh food packaged in trays must be correctly sealed to protect the internal atmosphere and avoid contamination or deterioration. Due to the speed of production, it is not possible to have human quality inspection. Thus, automatic fault detection is a must to reach high production volume. This work describes a deep neural network based on Principal Component Analysis Network (PCANet) for food tray sealing fault detection. The input data come from hyperspectral cameras, showing more characteristics than regular industrial cameras or the human eye as they capture the spectral properties for each pixel. The proposed classification…
Fast ultrasonic phased array inspection of complex geometries delivered through robotic manipulators and high speed data acquisition instrumentation
2016
Performance of modern robotic manipulators has enabled research and development of fast automated non-destructive testing (NDT) systems for complex geometries. This paper presents recent outcomes of work aimed at removing the bottleneck due to data acquisition rates, to fully exploit the scanning speed of modern 6-DoF manipulators. State of the art ultrasonic instrumentation has been integrated into a large robot cell to enable fast data acquisition, high scan resolutions and accurate positional encoding. A fibre optic connection between the ultrasonic instrument and the server computer enables data transfer rates up to 1.6GB/s. Multiple data collection methods are compared. Performance of …