Manufacturing of bone substitute implants using Selective Laser Melting

摘要

Selective Laser Melting (SLM) is a Rapid Manufacturing technique which enables direct manufacturing of three-dimensional parts with high bulk density on the base of individual three-dimensional data, including computer tomography models of anatomical structures. A new approach follows a regenerative strategy for manufacturing of bone substitute implants. The SLM process is adapted for bioresorbable materials (biopolymer, bioceramic) to build individual implants which will dissolve in the body and be replaced by new bone. The pore structure of the implant is essential for bony ingrowth especially for critical size defects. With the additive technique SLM it is possible to manufacture implants with a defined internal porous structure. Depending on the field of application different materials will gain different specifications concerning for example the degradation time in the body or the mechanical properties of the implant. Using Selective Laser Melting the manufacturing of individual bioresorbable implants will be possible. This work describes the new approach for the qualification of SLM to process polylactide (PLLA) and a composite material polylactide and β-tricalcium phosphate (PLLA/β-TCP). To achieve this the materials morphology has to be prepared for the SLM process and a processing window for the above mentioned materials has to be identified varying the process parameters such as laser power, scanning velocity and laser beam diameter. The process temperature is kept low to prevent degradation of the polymer during melting and to prevent a phase transition of the bioceramic β-TCP.