Venturing into incremental forming of polycarbonate sheets through automated toolpath generation for improved industrial applications
摘要
Shaping of polymer sheets into complex shapes has been traditionally achieved using thermoforming process. However, for customized and complex geometries it is not economical to make dedicated moulds. Thus, Incremental Sheet Forming (ISF) has been explored for polymer sheet forming without the need of a dedicated moulds. ISF is a die-less and an adaptable manufacturing process, which offers unique advantages over other forming methods, due to its low tooling cost, rapid geometric customization, and the ability to form complex shapes through localized plastic deformation. Polycarbonate (PC), an engineering-grade amorphous polymer, is widely utilized for automotive, aerospace, and biomedical applications, etc., owing to its good impact resistance, optical transparency, and thermal stability. This work experimentally studies the formability of PC sheets with respect to the variation in the process parameters of incremental step depths and toolpaths during the ISF process. Furthermore, to improve the usability and industrial adoption of this process, a MATLAB®-based-graphical user interface (GUI) was developed, enabling users to input geometrical parameters, and generate different toolpaths to fabricate various geometrical 3D shapes. The study demonstrated that the spiral toolpath yielded higher tensile strength, better elongation through thermo-mechanical softening, and improved geometrical deformation compared to the conventional contour toolpath. Moreover, the smallest step depth of 0.1 mm assisted in achieving uniform surface finish with minimal tool markings on the formed part. With spiral strategy, lower average surface roughness of 0.97 μm were observed with lesser strain accumulation, relative to the contour, having the roughness of 1.4 μm. Whereas, increasing the wall angle from 30° to 60° also enhanced the viscoelastic material flow and surface quality with less deformation gradients, leading to higher formability and delay in localized fracture. Overall, these outcomes showed that with optimized parameters and incorporation of the GUI, can strengthen the potential of the ISF process for industrial-scale polymer forming applications.