Implementação de célula robótica na fabricação de peças e esculturas de rochas ornamentais

Abstract

The ornamental stone processing sector, a cornerstone of the economy, still relies heavily on manual machining and finishing processes. These methods demand significant physical exertion and expose workers to serious ergonomic and occupational hazards, such as noise, vibration, and damp environments. Consequently, this study aims to develop and implement a robotic cell for manufacturing ornamental stone parts and sculptures. The case study was conducted at the company Marmoraria O Caminho das Pedras with the goal of automating the production process to boost productivity, standardization, and quality, while also minimizing health risks to workers. The methodology involved gathering data on the current process, selecting a pilot workpiece featuring 3D curves, sizing the robotic cell, and running computer simulations using CAD/CAM systems (Ency software) to generate toolpaths and prevent collisions. The project utilized a KUKA KR 240-2 US articulated robot; a load analysis confirmed that the combined tooling and dynamic forces required only 90.3 kg (approximately 38%) of the robot's 240 kg rated capacity, ensuring mechanical rigidity and vibration-free operation. To validate the approach, a pilot workpiece was produced using both manual and robotic methods, enabling a comparative analysis of production times, visual quality, and dimensional accuracy. The results showed that, although the net production time was similar (27h 55min for manual vs. 26h 18min for robotic), automation cut the operation's lead time in half—dropping from 5 days to 2.5 working days—thanks to the robot's ability to work continuously without needing breaks for fatigue. Quality analysis revealed that robotic machining produced a uniform surface finish and millimeter-level precision, with minimal dimensional deviations (ranging from 0.1 mm to 2.4 mm), whereas the manual process exhibited organic variations and deviations reaching up to 16.9 mm on complex sections of the sculpture. It is concluded that the implementation of the robotic cell represents a highly viable and innovative technological solution for the stone industry. This technology integrates mechanical engineering and industrial automation concepts, resulting not only in a significant improvement in the aesthetic standards demanded by high-end markets but also in a direct enhancement of worker operational safety. [resumo fornecido pelo autor]