Embedding a surface acoustic wave sensor and venting into a metal additively manufactured injection mould tool for targeted temperature monitoring

Rokas Šakalys; Christopher O'Hara; Mandana Kariminejad; Albert Weinert; Mohammadreza Kadivar; Bruno Zluhan; Marion McAfee; Gerard McGranaghan; David Tormey; Ramesh Raghavendra

doi:10.1007/s00170-023-12932-7

Embedding a surface acoustic wave sensor and venting into a metal additively manufactured injection mould tool for targeted temperature monitoring

Int J Adv Manuf Technol. 2024;130(11-12):5627-5640. doi: 10.1007/s00170-023-12932-7. Epub 2024 Jan 25.

Authors

Rokas Šakalys^{1

2}, Christopher O'Hara^{1

3}, Mandana Kariminejad^{1

3}, Albert Weinert^{1

3}, Mohammadreza Kadivar^{1

3}, Bruno Zluhan², Marion McAfee^{1

3}, Gerard McGranaghan^{1

3}, David Tormey^{1

3}, Ramesh Raghavendra^{1

2}

Affiliations

¹ I-Form, the SFI Research Centre for Advanced Manufacturing, University College Dublin, Room L0.13, CSCB Building, O'Brien Centre for Science (East), Belfield, Dublin 4, Ireland.
² South Eastern Applied Materials Research Centre (SEAM), South East Technological University, Waterford, X91TX03 Ireland.
³ Centre for Precision Engineering Material and Manufacturing Research (PEM Research Centre), Atlantic Technological University, Ash Lane, Sligo, F91 YW50 Ireland.

Abstract

Injection moulding (IM) tools with embedded sensors can significantly improve the process efficiency and quality of the fabricated parts through real-time monitoring and control of key process parameters such as temperature, pressure and injection speed. However, traditional mould tool fabrication technologies do not enable the fabrication of complex internal geometries. Complex internal geometries are necessary for technical applications such as sensor embedding and conformal cooling which yield benefits for process control and improved cycle times. With traditional fabrication techniques, only simple bore-based sensor embedding or external sensor attachment is possible. Externally attached sensors may compromise the functionality of the injection mould tool, with limitations such as the acquired data not reflecting the processes inside the part. The design freedom of additive manufacturing (AM) enables the fabrication of complex internal geometries, making it an excellent candidate for fabricating injection mould tools with such internal geometries. Therefore, embedding sensors in a desired location for targeted monitoring of critical mould tool regions is easier to achieve with AM. This research paper focuses on embedding a wireless surface acoustic wave (SAW) temperature sensor into an injection mould tool that was additively manufactured from stainless steel 316L. The laser powder bed fusion (L-PBF) "stop-and-go" approach was applied to embed the wireless SAW sensor. After embedding, the sensor demonstrated full functionality by recording real-time temperature data, which can further enhance process control. In addition, the concept of novel print-in-place venting design, applying the same L-PBF stop-and-go approach, for vent embedding was successfully implemented, enabling the IM of defectless parts at faster injection rates, whereas cavities designed and tested without venting resulted in parts with burn marks.

Keywords: Additively manufactured injection mould tools; In-mould sensors; Injection moulding; Print-in-place venting; Wireless sensor embedding.