Pilot feedback electronic imaging at elevated temperatures and its potential for in-process electron beam melting monitoring

Wong, Hay ORCID: 0000-0003-1717-2653, Neary, Derek, Jones, Eric, Fox, Peter ORCID: 0000-0003-3442-8630 and Sutcliffe, Chris (2019) Pilot feedback electronic imaging at elevated temperatures and its potential for in-process electron beam melting monitoring. ADDITIVE MANUFACTURING, 27. pp. 185-198.

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Abstract

Electron Beam Melting (EBM) is an increasingly used Additive Manufacturing (AM) technique employed by many industrial sectors, including the medical device and aerospace industries. The application of this technology is, however, challenged by the lack of process monitoring and control system that underpins process repeatability and part quality reproducibility. An electronic imaging system prototype has been developed to serve as an EBM monitoring equipment, the capabilities of which have been verified at room temperature and at 320 ± 10 °C. Nevertheless, in order to fully assess the applicability of this technique, electronic imaging needs to be conducted at a range of elevated temperatures to fully understand the influence of temperature on electronic image quality. Building on top of the previous electronic imaging trials at room temperature, this paper disseminates the essential step changes to allow high temperature electronic imaging: (1) modification of a signal amplifier to deal with high electron beam current during electron beam heating, and (2) design of an open-source electron beam heating algorithm to maximise flexibility for user-defined heating strategy. In this paper, electronic imaging pilot trials at elevated temperatures, ranging from room temperature to 650 °C, were carried out. Image quality measure Q of the digital electron images was evaluated, and the influence of temperature was investigated. In this study, raw electronic images generated at higher temperatures had greater Q values, i.e. better global image quality. It has been demonstrated that, for temperatures between 30°C-650°C, the influence of temperature on electronic image quality was not adversely affecting the visual clarity of image features. It is thus envisaged that the prototype has a potential to contribute to in-process EBM monitoring, and this paper has served as a crucial precursor to the ultimate goal of carrying out electronic imaging under real EBM building condition.

Item Type:	Article
Uncontrolled Keywords:	Additive manufacturing, Electron beam melting, In-process monitoring, Quality control, Electronic imaging
Depositing User:	Symplectic Admin
Date Deposited:	25 Apr 2019 10:46
Last Modified:	19 Jan 2023 00:53
DOI:	10.1016/j.addma.2019.02.022
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3038335