Product Code: ICA13_1404

Embedding Optical Fibers Into Stainless Steel Using Laser Additive Manufacturing
Authors:
Dirk Havermann, Heriot-Watt University; Edinburgh USA
William N. Macpherson, Heriot-Watt University; Edinburgh Great Britain
Robert R.J. Maier, Heriot-Watt University; Edinburgh Great Britain
Duncan P. Hand, Heriot-Watt University; Edinburgh Great Britain
Presented at ICALEO 2013

Laser Additive Manufacturing provides novel and exciting possibilities when constructing 3-dimensional free form components in polymers and metals. The process of building 3-D components from the inside-out, opens up the possibility of embedding sensors directly into the heart of a component. Fibre Bragg gratings are an essential component of smart composite materials and are already used for delivering in-situ measurements of polymer components. Recently developed high temperature compatible fibre Bragg gratings, suitable for continuous use at temperatures of up to 1000 C, provide opportunity of extending sensing capabilities to metallic components.

We have developed a process to embed optical sensors based on Fibre Bragg Gratings into stainless steel (SS 316). The optical fibres are first of all coated with Nickel (using a combination of sputtering and electroplating) to improve protection during the embedding process and to enable bonding to the metal environment. In a two step process, these nickel coated optical fibres, with an outer diameter of around half a millimetre, are laser welded onto a stainless steel substrate and subsequently encapsulated using a laser based powder sintering process. We demonstrate that nickel coated optical fibres can be embedded into stainless steel components by using laser based manufacturing processes and that these fibres can deliver in-situ measurements of applied strain and temperature changes.