3D Scanner Inspection and Shape Correction of SLS parts through Reverse Engineering compensation

The aim of this thesis is the scouting and implementation of a metrology system in the design loop for the production of elements in Additive Manufacturing, and in particular with Selective Laser Sintering (SLS). An Optical scanner has been tested and study on the repeatability of measurements taken on part produced with SLS have been performed. Additive manufacturing is intended to be a fast technology to produce prototypes or small batches of elements, and it usually takes different iteration for the element to achieve the desired tolerances. Each iteration is composed by production, measurement and design adjustment. Implementing a new system such as a 3D scanner to perform measurement can give faster and more detailed information about the shape of the produced element. The work in the thesis is divided in two main part. The first part takes into account all the measurement process and methods. When all the equipment has been created to allow a good measuring setup and the data have been acquired through the GOM Suite software, it is possible in fact to acquire single points measurements or entire faces/geometries, according to the type of feedback required. The software can be also used to give visual maps of the deviations to the designer or the process engineer, in order to understand the behaviour of an entire job at different shapes and parameters of the printing machine. The second part of the work is focused on the correction and compensation of the deviation observed in the measuring part. Different ways are suggested for the correction, using completely different approaches. The more traditional way will be to use the data obtained from the measurement in the CAD file effectively changing the dimensions of the part’s features. The changes can be obtained applying the measurement by hand or linking the dimensions in the CAD file to the measurement exported in an Excel file. Another interesting approach to apply compensations on the file is through the use of a Reverse Engineering software (Zeiss Reverse Engineering is the one used in this thesis) in order to automatically correct the shape of the object. This will create a freeform surface that will be suitable to run a new printing iteration. The works present the entire workflow from the creation of the measuring setup and program to the effective creation of the measurements on the part and the exportation of the data. The correction process is presented as well, describing pros and cons of the different software and methods used to perform the corrections. A compendium of the best workflow to achieve the more reliable and fast result is proposed at the end.