Study of the features of permanent and usual reverse-engineering methods of details of complex shapes

The subject of the study is sustainable reverse engineering and conventional reverse engineering of aviation equipment (AE) samples. The object of the study is the geometric accuracy of the extracted portrait of a part of a complex shape in comparison with the constructed analytical standard (AS). The work is aimed at researching the methods of sustainable reverse engineering and conventional reverse engineering on the example of the digitization of the box of the AE steering machine, chosen as a part of a complex shape. For this, a portrait of the "*.stl" and AS format file was created and compared by performing a control operation with the determination of the time spent. A structural and technological analysis of the box of the AE steering machine was carried out, which showed that the box has through holes of various diameters (from 10 to 41.6 mm) and shapes (square, trapezoidal, round); thin walls between holes (up to 1.6 mm); right angles and their rounding radii (up to 1–4 mm); the thickness of the body walls is 2.4 mm, etc. 3D scanner – ARTEC SPACE SPIDER (Luxembourg) was selected and scanning was performed. According to the analysis of research methods of reverse engineering, it was established that the use of permanent and conventional reverse engineering allows, in the first case, to quickly manufacture a part by 3D printing or milling on CNC machines, and in the second case, to create its AS with the provision of the specified geometric accuracy. The difference in time between permanent and normal reverse engineering was 8 hours in favor of the former. Control of the ideal portrait according to the AS of the AE steering machine body showed the maximum deviations from –0.30 mm to +0.23 mm and the minimum deviations from –0.04 mm to +0.08 mm. The smallest indicators were observed on vertical and horizontal planes, and the largest - in cities with plane slopes, corners and small radii. This made it possible to establish that the existing capabilities of the Geomagic Design X software for correcting the received portrait of the "*.stl" format file currently do not guarantee the provision of geometric accuracy requirements (up to ±0.5 mm) for the manufacture of an experimental part of a complex shape – the AE steering machine body with 3D printing. The resulting ideal portrait can be used to manufacture a part by milling on CNC machines, taking into account deviations at the stage of process model formation, which can become the topic of further research.