Novel 3D coating of bioactive glass and metallic composites

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The orthopaedic implant market is consistently projected to show strong growth, particularly in the joint reconstructionsector. At a time where healthcare budgets are under severe pressure, there is a need for novel hip implants that deliver abetter quality of clinical outcome, but at the same or reduced cost. Implants are coated to aid implant bone-integration, andthe composition and structure of these coating is critical to the speed and strength of implant-bone integration and hencethe clinical outcome. The current coating is a combination of titanium (for strength) and bioactive glass (to facilitate boneingrowth), materials which have very different thermal properties and therefore must be laid down in two-stages if using aconventional coating process. The ability to apply these materials by a novel 3D printing process, potentially in one-step,will transform design and manufacture of orthopaedic implants. It will provide much greater design freedom to create newfunctionally optimised material combinations and structures not achievable by a conventional process. This projectintegrates the capabilities of SMEs operating end-to-end from design to product supply and the expertise of the Universityof Sheffield in end-to-end simulation. Using a range of simulation methodologies developed by UoS in a series ofpreviously funded programmes (e.g. IMMPETUS EPSRC grants, EP/E063497 and EP/F023464), the Mercury Centre willapply these to design and simulate the end-to-end manufacturing of the novel 3D coating of bioactive glass and metalliccomposites. We will use phase field modelling to simulate the melting, fluid dynamics, solidification and phasetransformations during AM to optimise the process conditions for this application. We will use our unique combined finiteelement/discrete element modelling to simulate the heat transfer, residual stresses and interaction between the metal andbioglass. Multi-scale modelling will be used to link microstructure and properties throughout the manufacturing process.This will extended to include the behaviour of the novel composite in vivo. It will deliver from design to supply a noveladditive manufacturing (AM) process to apply novel interpenetrating 3D glass and metallic composite coatings onto 3Dsurfaces initially for orthopaedic (hip) implants. The coatings will enable design and manufacture of smaller (minimallyinvasive) implants with 'large implant' performance having better mechanical stability and faster integration with bone thusimproving long-term clinical performance and a reduced revision rate. This delivers a significantly better clinical outcomefor patients and savings for the health service. The envisaged AM process has the potential to be faster and lower costthan current two-stage deposition and to enable the manufacture (possibly in near-patient areas) of implants matched tothe patient using pre-operative bone scans. Transferability to other sectors will be demonstrated by the manufacture of asolar diffuser material.