Mesh-offset-based method to generate a delta volume to support the maintenance of partially damaged parts through 3D printing

Three-dimensional (3D) printing technology is an excellent tool for implementing multi item, small scale production or for manufacturing objects of complex shape, and has been utilized in many areas of daily life. One typical application is parts maintenance. For a partially damaged part to be repaired using a 3D printer, it is essential to generate a delta volume for the damaged area. A typical method of delta volume generation is to create a mesh using Delaunay triangulation or Poisson surface reconstruction from the point cloud of a laser scan of the damaged part and to perform a boolean subtraction operation with the mesh of the original part. However, when generating the delta volume, this method is prone to error due to noise, non-uniform sampling, and missing data in the point cloud. To address this problem, we propose a mesh offset based method capable of robust delta volume generation despite point cloud noise. This method consists of four steps: preprocessing, point cloud extraction, mesh extraction, and delta volume extraction. To experimentally validate the proposed method, a prototype system was developed and a numerical implementation was performed for a partially damaged ball valve.