Developing additive manufacturing methodology towards the in situ repair of articular cartilage defects

Mummery, Ailsa Paige ORCID: 0009-0005-8976-0173 (2024). Developing additive manufacturing methodology towards the in situ repair of articular cartilage defects. University of Birmingham. Ph.D.

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Abstract

In situ additive manufacturing as a next step in the development of technologies towards repair of articular cartilage defects to treat a younger, more active population, and to delay full knee replacement. The main steps in the in situ AM workflow are explored in depth to investigate best-practice and technologies available for development. This thesis covers 3D optical scanning, alignment of conformal prints, toolpath development for in situ additive manufacture of surface additions and filling of surface defects, and in situ additive manufacture of PLA constructs onto ’known’ and ’unknown’ surfaces. Investigation of the 3D scanning parameters presents lighter coloured objects as more accurately captured (compared to darker objects) by the EinScan-SP 3D scanner. The optimum print parameters for dimensional accuracy for additive manufacture of thermally bonded polylactic acid were 40 mm/s print speed and 200 °C. For scan dimensional accuracy, a print speed between 30 and 60 mm/s, and print temperature of 200 °C produced maximum dimension deviations of 0.2 mm. A series of surfaces successfully underwent in situ conformal additive manufacture on the top surface, or the base of a surface defect. First, basic cuboids previously 3D printed, with varying complexity of top surface geometry. Next, clay approximations of the radius of curvature of human knee articular surfaces. Finally, an "unknown" surface (Sawbone bone model). In conclusion, this thesis provides in depth proof-of-concept for the development of a technique for additive manufacturing in situ for conformal additive manufacturing onto ’unknown’ surfaces

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):