Correlating nano-scale surface replication accuracy and cavity temperature in micro-injection moulding using in-line process control and high-speed thermal imaging

Federico Baruffi, Mert Gülçür, Matteo Calaon, Jean-Michel Romano, Pavel Penchev, Stefan Dimov, Ben Whiteside, Guido Tosello*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Micro-injection moulding (μIM) stands out as preferable technology to enable the mass production of polymeric components with micro- and nano-structured surfaces. One of the major challenges of these processes is related to the quality assurance of the manufactured surfaces: the time needed to perform accurate 3D surface acquisitions is typically much longer than a single moulding cycle, thus making impossible to integrate in-line measurements in the process chain. In this work, the authors proposed a novel solution to this problem by defining a process monitoring strategy aiming at linking sensitive in-line monitored process variables with the replication quality. A nano-structured surface for antibacterial applications was manufactured on a metal insert by laser structuring and replicated using two different polymers, polyoxymethylene (POM) and polycarbonate (PC). The replication accuracy was determined using a laser scanning confocal microscope and its dependence on the variation of the main μIM parameters was studied using a Design of Experiments (DoE) experimental approach. During each process cycle, the temperature distribution of the polymer inside the cavity was measured using a high-speed infrared camera by means of a sapphire window mounted in the movable plate of the mould. The temperature measurements showed a high level of correlation with the replication performance of the μIM process, thus providing a fast and effective way to control the quality of the moulded surfaces in-line.
Original languageEnglish
JournalJournal of Manufacturing Processes
Volume47
Pages (from-to)367-381
ISSN1526-6125
DOIs
Publication statusPublished - 2019

Keywords

  • Micro-injection moulding
  • Flow visualization
  • Surface replication
  • In-line quality assurance

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