The reconstructed models and pointclouds do not accommodate for hollow structures, such as holes or cavities. The reverse engineering method presented here is based on the digital simulation of the extrusion process of FDM type 3D printing. Such code files contain instructions for the 3D printer to move and control its actuator, in case of Fused Deposition Modeling (FDM), the printhead that extrudes semi-molten plastics. GCode is a machine code that is used for 3D printing among other applications, such as CNC routers. The authors present a method to reverse engineer 3D printer specific machine instructions (GCode) to a point cloud representation and then a STL (Stereolithography) file format. Developed measurement system can be used during wind tunnel tests, as well as only for servo-mechanism parameter testing.

Experimental studies show that before wind tunnel tests, selected servomechanism should be tested in terms of maintaining the parameters declared by the manufacturer, especially during continuous operation. In the paper, test methodology were also presented. Developed test rig allow to register time histories of servo-rotor position and temperature during for different values of applied load.

The application designed to monitor the operating status of the servomechanism was prepared in the LabVIEW software and was implemented on the myRIO platform. Proposed system would ensure continuous monitoring of servo-rotor position and servo-motor temperature and would avoid uncontrolled change of control surface position. These devices could be applied to set specific position of control surface. The paper present the results of work on measurement system dedicated to hardware used during wind tunnel tests, especially to servomechanisms. The main motivation to develop a new software resulted from the observation that sometimes the original solid model is no longer available, while there is a need to change some geometry details or settings before production stage. The final part shows an attempt of applying Poisson Surface Reconstruction in order to obtain the original geometry. In the developed algorithm the linear interpolation was added to obtain intermediate points between locations of the print head for longer sections. These points represent particular locations of the print head. Next the reverse engineering was applied and GCODE files were converted to points sets. All these models were converted to GCODE files. In the investigations three different 3D models were created: a) shell model (a casing) b) solid model (a gear) c) model with curvilinear elements (a screw). The paper presents a method of conversion of GCODE files designed for additive manufacturing in 3D printers to a format which may be conveniently visualized.

Free gcode files for 3d printing