New approach to minimise surface roughness in Polytetrafluoroethylene (PTFE) through robotic spindle speed control

Abstract

Machining Polytetrafluoroethylene (PTFE) is increasingly popular due to its chemical resistance, low friction, and high-temperature stability. These properties make PTFE crucial to industries that need fine surface finishes, such as aerospace, biomedical devices, and electronics. However, achieving practical surface quality remains challenging, particularly in robotic machining processes. This research examines the impact of spindle speed on the surface roughness of PTFE during robotic milling operation using KUKA KR120 R2700. Spindle speed was selected as the primary process parameter, and the experimental trials were conducted at four spindle speed levels: 4,500 RPM, 9,000 RPM, 13,500 RPM, and 18,000 RPM. The average roughness (Ra), root mean square roughness (Rq), and maximum peak-to-valley roughness (Rz) were measured through profilometry. Concurrently, a Scanning Electron Microscope (SEM) detected surface features with microscopic imperfections. The findings demonstrate a clear trend: a significant decrease in surface roughness values with a very high spindle speed, wherein 18,000 RPM provided the best results regarding the least surface defects and finer scratch lines. Moreover, the Ra value was the most significant in the present study and validated the trend between the spindle speed and surface finish quality. This research focuses on a new direction in enhancing the machinability of PTFE materials using a robotic milling technique in which spindle speed is optimised to improve the surface finish required in many industries. The research offers essential information for manufacturers desiring greater accuracy and control in PTFE processing and expands the knowledge base of robotic manufacturing technology for polymeric material. This research establishes the scene to address concerns about using robotic systems to improve surface finishes in various engineering applications.