This study focuses on new technologies for the production of medical implants using a combination of robotics and microplasma coatings. This involves robot assisted microplasma spraying (MPS) of a multilayer surface structure on a biomedical implant. The robot motion design provides a consistent and customised plasma coating operation. Based on the analytical model results, certain spraying modes were chosen to form the optimised composition and structure of the titanium/hydroxyapatite (HA) multilayer coatings. It is desirable that the Ti coated lower layer offer a dense layer to provide the implant with suitable structural integrity and the Ti porous layer and HA top layer present biocompatible layers which are suitable for implant and tissue integration. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to analyse the structure of the coatings. The new robot assisted MPS technique resulting from this research provides a promising solution for medical implant technology.

This paper presents new results of microplasma spraying (MPS) of laboratory-synthesized hydroxyapatite (HA) powder coatings onto trabecular substrates obtained by selective laser melting (SLM) of a certified titanium medical alloy powder. The aim of the study was to establish the possibility of combining the technologies of MPS and additive manufacturing (AM) for the possible production of custom-designed implants with increased surface biocompatibility, as well as to establish the MPS parameters that ensure chemical purity of the HA coating and satisfactory adhesion of the coatings to the substrate. The structural-phase compositions of the initial HA powder and the plasma-sprayed HA coating were studied by X-ray diffraction analysis and transmission electron microscopy, and the adhesion strength of the coating was tested according to the F1147 standard of the American Society for Testing and Materials (ASTM). The main results of the study are the following: the application of the MPS technology for HA coating with an average thickness of 150±50 μm on trabecular substrates obtained by the SLM method has been shown. The parameters of MPS of HA coatings onto titanium implants with a trabecular surface have been established. It is also proved that using the appropriate MPS parameters, it is possible to obtain a HA coating with a 95% level of HA phases, 93% level of crystallinity, and the adhesion strength to the trabecular substrate of 24.7±5.7 MPa, which complies with the requirements of the international medical standard (International Organization for Standardization [ISO] 13779-2:2018). These results are of significance for a wide range of researchers developing plasma spray technologies for the manufacture of biocompatible coatings.

The paper presents new results of automated path planning for an industrial robot manipulator performing microplasma spraying of coatings on substrates with complex surface shapes. Path planning and automatic generation of the manipulator motion program are performed using data of a preliminary 3D surface scanning by a laser triangulation distance sensor installed on the same robot arm. The automatic manipulator working tool path planning algorithm is based on the choice of the starting segment of the working tool trace as a geodetic line on the surface. An algorithm for optimal spatial curve approximation by a sequence of line segments and arcs has been developed as a part of the automatic manipulator program generation system. The developed algorithms and their software implementation were experimentally tested through robotic microplasma spraying of a protective coating on the surface of a jaw crusher plate, which was then successfully operated for crushing mineral raw materials.

No abstract

No abstract