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

Research output: Contribution to journalArticle

Authors

  • Federico Baruffi
  • Mert Gulcur
  • Matteo Calaon
  • Jean-Michel Romano
  • Ben Whiteside
  • Guido Tosello

Colleges, School and Institutes

External organisations

  • University of Bradford
  • Technical University of Denmark, Department of Mechanical Engineering
  • Technical University of Denmark

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.

Details

Original languageEnglish
Pages (from-to)367-381
Number of pages15
JournalJournal of Manufacturing Processes
Volume47
Early online date22 Oct 2019
Publication statusPublished - 1 Nov 2019

Keywords

  • micro-injection moulding, flow visualization, surface replication, in-line quality assurance