It is estimated that around 500,000 people are admitted to hospitals across Europe each year after having suffered bone, joint, maxillofacial trauma or degenerative diseases that require surgical attention using a customised implant. Added to this are the approximately 2.4 million people who are injured or disabled each year by road traffic accidents in Europe. Meaning that this work had the potential to benefit millions of people each year by reducing the lead times for patient-specific implants from 4-6 weeks to just 7 days.
This project saw us use our technical excellence to transfer a technology to a new sector to produce genuine benefits for the public, while also showing our capability to work to the necessarily exacting standards required by the medical profession.
- Certification of Laser Powder Additive Manufactured Components for Industrial Adoption in the Energy and Offshore Sectors
By 2015 there had been rapid progress in the field of AM as a process to create parts without the use of machining, moulding or casting. Having already shown significant potential for AM to reduce costs in both the aerospace and medical industries, while also demonstrating improved design freedom, weight reduction and lower tooling costs, complemented by reductions in carbon footprint and waste during manufacture, there was a need to create industry product certification guidelines to allow an increased adoption of the process by industry.
Working alongside Lloyd’s Register, we combined research and development efforts with real-world additive manufacturing practices to create new industry product certification guidelines - paving the way for more widespread adoption of the additive manufacturing technology and assisting industry in how best to tap in to its potential.
This project had a particular focus on the energy and offshore sectors, where it sought to identify potential applications for AM before undertaking practical work to determine optimum build parameters and produce components that could then be tested and certified to create the required industry guidelines.
Selective laser melting (SLM) and laser metal deposition (LMD) were the chosen processes to be used for this work, which was delivered as a joint industry project that provided the findings directly to the project sponsors, allowing interested energy and offshore industry operators the opportunity to benefit from the research.
- Validation of Process Models for Additive Manufacturing
Selective laser melting (SLM) was the subject of another project in 2017, where we worked with the SIMULIA brand of Dassault Systèmes to validate the use of finite element modelling (FEM) techniques to accurately simulate additive AM processes. The aim of this AM validation project was to allow for improved part design and process setup before any physical manufacturing takes place. The project results would reduce manufacturing defects in parts and support the development of AM technologies.
We used a Renishaw AM250 machine to produce double cantilever parts from Ti-6Al-4V Grade 23 metal powder with a particle size range of between 15 and 45μm (see figure 2). A 90° alternating scan strategy was used, comprising a series of parallel hatch lines and four boundary contours, which was rotated by 90° after every layer. Electrical discharge machining was used to cut away the support structures below the solid beam surfaces. Upon cutting, the presence of residual stresses generated deflections of the remaining double-sided cantilever beam structure. The out-of-plane deflections were measured using a FaroArm precision measuring tool.
The AM simulations used physics-based FEM formulations to input exact machine information about the powder recoating sequence, laser scan path, and process parameters into the FE model (see figure 3). These models enabled progressive element activation and heating computations, as well as solid surface cooling data during build progression. The simulation model employed temperature-dependent material properties for the heat transfer and stress analysis simulations.
The final validation was achieved through a technical comparison of the physical SLM-manufactured test pieces and the FEM predictions (see figure 4), which showed that there was a strong correlation between the predictions and the test measurements, providing confidence in the modelling approach.
This work helped progress AM processes through the validation of the use of simulations for AM part production.
- D.E.E.P. Project
Having used our expertise to help promote and enable the use of AM in industries including automotive, medical, energy, offshore and aerospace, we are now part of a new collaborative project that will see AM processes investigated for the highly regulated and complex maritime sector.
The Digitally Enabled Efficient Propeller (D.E.E.P.) project has been created to assess a range of advanced AM processes, integrated with digital twin simulation technology, for the creation of a new generation of smart, cyber-physical, marine propellers that are able to monitor their own performance across their operational life.
TWI has joined a consortium of world-leading experts in their respective fields to investigate the technology readiness of different AM processes for the highly-regulated and operationally-complex maritime sector. This work includes benchmarking performance against conventional manufacturing methods with the aim of establishing a pathway to classification approval and type certification. This approach will ensure that the project not only delivers technical innovation, but also creates a credible framework for industrial adoption and regulatory compliance.
With the project now underway, the consortium will begin by evaluating AM processes before creating, testing, and validating a demonstrator propeller on Newcastle University’s research vessel, with the long-term aim of enabling type approval and scaling production for commercial adoption by the global fleet.