Browsing by Author "Vasilev, Momchil"

Now showing 1 - 4 of 4
  • Thumbnail Image
    ItemOpen Access
    Collaborative robotic wire + arc additive manufacture and sensor-enabled in-process ultrasonic non-destructive evaluation
    (MDPI, 2022-05-31) Zimermann, Rastislav; Mohseni, Ehsan; Vasilev, Momchil; Loukas, Charalampos; Vithanage, Randika K. W.; Macleod, Charles N.; Lines, David; Javadi, Yashar; Espirindio E Silva, Misael Pimentel; Fitzpatrick, Stephen; Halavage, Steven; Mckegney, Scott; Pierce, Stephen Gareth; Williams, Stewart; Dingv, Jialuo
    The demand for cost-efficient manufacturing of complex metal components has driven research for metal Additive Manufacturing (AM) such as Wire + Arc Additive Manufacturing (WAAM). WAAM enables automated, time- and material-efficient manufacturing of metal parts. To strengthen these benefits, the demand for robotically deployed in-process Non-Destructive Evaluation (NDE) has risen, aiming to replace current manually deployed inspection techniques after completion of the part. This work presents a synchronized multi-robot WAAM and NDE cell aiming to achieve (1) defect detection in-process, (2) enable possible in-process repair and (3) prevent costly scrappage or rework of completed defective builds. The deployment of the NDE during a deposition process is achieved through real-time position control of robots based on sensor input. A novel high-temperature capable, dry-coupled phased array ultrasound transducer (PAUT) roller-probe device is used for the NDE inspection. The dry-coupled sensor is tailored for coupling with an as-built high-temperature WAAM surface at an applied force and speed. The demonstration of the novel ultrasound in-process defect detection approach, presented in this paper, was performed on a titanium WAAM straight sample containing an intentionally embedded tungsten tube reflectors with an internal diameter of 1.0 mm. The ultrasound data were acquired after a pre-specified layer, in-process, employing the Full Matrix Capture (FMC) technique for subsequent post-processing using the adaptive Total Focusing Method (TFM) imaging algorithm assisted by a surface reconstruction algorithm based on the Synthetic Aperture Focusing Technique (SAFT). The presented results show a sufficient signal-to-noise ratio. Therefore, a potential for early defect detection is achieved, directly strengthening the benefits of the AM process by enabling a possible in-process repair.
  • Thumbnail Image
    ItemOpen Access
    In-process non-destructive evaluation of metal additive manufactured components at build using ultrasound and eddy-current approaches
    (Elsevier, 2023-11-03) Zimermann, Rastislav; Mohseni, Ehsan; Foster, Euan A.; Vasilev, Momchil; Loukas, Charalampos; Vithanage, Randika K. W.; Macleod, Charles N.; Lines, David; Pimentel Espirindio E. Silva, Misael; Fitzpatrick, Stephen; Halavage, Steven; McKegney, Scott; Rizwan, Muhammad Khalid; Pierce, Stephen Gareth; Williams, Stewart; Ding, Jialuo
    Metal additive manufacturing is rapidly gaining popularity and interest from sectors aiming to produce larger-scale high-value components cost-effectively. To ensure each component is leaving the fabrication cell defect-free, it is highly desirable to inspect each layer or selected volume of the build. This is a significant challenge, given that conventional non-destructive evaluation (NDE) is a post-manufacturing operation. The opportunity exists in the development of novel flexible automated manufacturing systems aiming to merge deposition and inspection. Hence, enabling defect detection at the point of the creation allows subsequent rapid repair or reduction in scrappage. In this work, the authors present research from one such multi-robot cell, where a directed energy deposition process called wire + arc additive manufacture is used to build components while novel in-process ultrasound and eddy-current approaches are deployed to inspect a component with artificially embedded reflectors. The outcome of this work demonstrates a promising ability to merge manufacturing and NDE into a single process and hence, strengthen the overall benefits of metal additive manufacturing fields.
  • Thumbnail Image
    ItemOpen Access
    Transforming industrial manipulators via kinesthetic guidance for automated inspection of complex geometries
    (MDPI, 2023-04-05) Loukas, Charalampos; Vasilev, Momchil; Zimmerman, Rastislav; Vithanage, Randika K. W.; Mohseni, Ehsan; MacLeod, Charles N.; Lines, David; Pierce, Stephen Gareth; Williams, Stewart; Ding, Jialuo; Burnham, Kenneth; Sibson, Jim; O’Hare, Tom; Grosser, Michael R.
    The increased demand for cost-efficient manufacturing and metrology inspection solutions for complex-shaped components in High-Value Manufacturing (HVM) sectors requires increased production throughput and precision. This drives the integration of automated robotic solutions. However, the current manipulators utilizing traditional programming approaches demand specialized robotic programming knowledge and make it challenging to generate complex paths and adapt easily to unique specifications per component, resulting in an inflexible and cumbersome teaching process. Therefore, this body of work proposes a novel software system to realize kinesthetic guidance for path planning in real-time intervals at 250 Hz, utilizing an external off-the-shelf force–torque (FT) sensor. The proposed work is demonstrated on a 500 mm2 near-net-shaped Wire–Arc Additive Manufacturing (WAAM) complex component with embedded defects by teaching the inspection path for defect detection with a standard industrial robotic manipulator in a collaborative fashion and adaptively generating the kinematics resulting in the uniform coupling of ultrasound inspection. The utilized method proves superior in performance and speed, accelerating the programming time using online and offline approaches by an estimate of 88% to 98%. The proposed work is a unique development, retrofitting current industrial manipulators into collaborative entities, securing human job resources, and achieving flexible production.
  • Thumbnail Image
    ItemOpen Access
    Ultrasonic phased array inspection of wire plus arc additive manufacture samples using conventional and total focusing method imaging approaches
    (British Institute of Non-destructive Testing, 2019-03-01) Javadi, Yashar; MacLeod, Charles N.; Pierce, Stephen G.; Gachagan, Anthony; Lines, David; Mineo, Carmelo; Ding, Jialuo; Williams, Stewart W.; Vasilev, Momchil; Mohseni, Ehsan; Su, Riliang
    In this study, three aluminium samples produced by wire + arc additive manufacture (WAAM) are inspected using ultrasonic phased array technology. Artificial defects are machined using a centre drill, ø 3 mm, and electrical discharge machining (EDM), ø 0.5-1 mm, in a cylindrical through-hole topology. The samples are first inspected using a singleelement wheel probe mounted on a KUKA robot in order to investigate the feasibility of using a conventional ultrasonic transducer approach. Unfortunately, the wheel probe is found to be unsuitable for scanning the WAAM specimens and ultrasonic phased arrays are employed next. The set-up includes 5 MHz and 10 MHz arrays (128 elements) in direct contact with the sample surface using both the conventional and total focusing method (TFM) imaging techniques. Using an FIToolbox (Diagnostic Sonar, UK) as the controller, a phased array aperture of 32 elements is used to perform a focused B-scan with a range of settings for the transmit focal depth. All of the reflectors (including those located near the WAAM top surface) are successfully detected with a combination of conventional phased array and TFM, using a range of settings and set-ups, including bottom surface inspection, application through a plexiglass wedge and variation of the scanning frequency.