Now showing 1 - 4 of 4
  • Publication
    Detecting Voids in 3D Printing Using Melt Pool Time Series Data
    Powder Bed Fusion (PBF) has emerged as an important process in the additive manufacture of metals. However, PBF is sensitive to process parameters and careful management is required to ensure the high quality of parts produced. In PBF, a laser or electron beam is used to fuse powder to the part. It is recognised that the temperature of the melt pool is an important signal representing the health of the process. In this paper, Machine Learning (ML) methods on time-series data are used to monitor melt pool temperature to detect anomalies. In line with other ML research on time-series classification, Dynamic Time Warping and k-Nearest Neighbour classifiers are used. The presented process is effective in detecting voids in PBF. A strategy is then proposed to speed up classification time, an important consideration given the volume of data involved.
      727Scopus© Citations 29
  • Publication
    Supporting Problem-based Learning in Moodle using Personalised, Context- specific Learning Episode Generation
    Providing learners with a list of disparate search results is not always conducive to learning. In particular, this approach lacks learning structure, and learners have to sift through lists of resources in order to make sense of them and to find the level of detail they require. In this paper we outline the Moodle Help Block, a Moodle block plug-in that provides learners with Just-In-Time context relevant learning material using a defined pedagogical strategy. The Moodle Help Block uses a combination of Semantic Web, Social Web and learning composition technology to generate learning episodes as needed by learners. The Moodle help block conducts a dialogue with the learner to extrapolate where a given learner’s knowledge gaps lie and generate learning episodes with learning material to help the learner overcome their knowledge deficit. It is thought that the Moodle Help Block can assist learners with targeted help when a teacher is not available.
  • Publication
    Content on demand for fourth year advanced materials and manufacturing students
    (International Symposium of Engineering Education, 2012-07-18) ; ; ; ; ;
    There is growing recognition of the key role that social and informal learning play in Higher Education. There is also increasing interest in technologies that enable, capture and channel this type of learning to students at their point of need and personalised to their ability. The objective of this project was to leverage research technologies from the areas of adaptive hypermedia, social and semantic search to create an application to deliver learning resources to students tailored to their specific learning needs. In this project, some 130 digital learning resources, specific to a final year advanced materials and manufacturing module, were made available to the students via a Help Block plugin in the Moodle Virtual Learning Environment. The students were required to use the Help Block as a just-in-time learning resource to help them complete a continuous assessment assignment. The assignment required the students to select an advanced manufacturing process and associated material describing the manufacturing process steps, control and specifications and presenting the technological benefits of the process and material used relative to competing processes and materials. Post-trial, students were asked to complete a questionnaire to describe their experience with the Help Block in terms of whether it assisted them in completing the assignment, for example, and its ease of use. The system, evaluation findings, and some suggestions for future system enhancements are presented in the paper.
  • Publication
    Laser micro-processing of amorphous and partially crystalline Cu45Zr48Al7 alloy
    (Springer-Verlag, 2010-06-15) ; ; ;
    This paper presents a microstructural study of laser micro-processed high-purity Cu45Zr48Al7 alloys prepared by arc melting and Cu-mould casting. Microprocessing of the Cu45Zr48Al7 alloy was performed using a Rofin DC-015 diffusion-cooled CO2 slab laser system with 10.6-μm wavelength. The laser was defocused to a spot size of 0.2 mm on the sample surface. The laser parameters were set to give 300- and 350-W peak power, 30% duty cycle and a 3000-Hz laser pulse repetition frequency (PRF). About 100-micrometer-wide channels were scribed on the surfaces of disk-shaped amorphous and partially crystalline samples at traverse speeds of 500 and 5000 mm/min. These channels were analysed using scanning electron microscopy (SEM) and 2D stylus profilometry. The metallographic study and profile of these processed regions are discussed in terms of the applied laser processing parameters. The SEM micrographs showed that striation marks developed at the edge and inside these regions as a result of the laser processing. The results from this work showed that microscale features can be produced on the surface of amorphous Cu–Zr–Al alloys by CO2 laser processing.
      492Scopus© Citations 12