Surface Finish Analysis in Single Point Incremental Sheet Forming of Rib-Stiffened 2024-T3 and 7075-T6 Alclad Aluminium Alloy Panels

Area of Science:

• Materials Science
• Manufacturing Engineering
• Surface Metrology

Background:

• Single Point Incremental Forming (SPIF) is crucial for aerospace applications, particularly with Alclad aluminium alloys.
• Maintaining surface integrity and controlling roughness are key challenges in SPIF of Alclad sheets.
• Alclad sheets consist of high-purity aluminium layers bonded to an alloy core.

Purpose of the Study:

• To analyze the interactions between SPIF process parameters and surface roughness parameters (Sa, Sz) of stiffened ribs.
• To investigate the influence of incremental vertical step size and tool rotational speed on surface quality.
• To develop predictive models for surface roughness in SPIF of Alclad panels.

Main Methods:

• Fabrication of stiffened ribs using EN AW-7075-T6 and EN AW-2024-T3 Alclad aluminium alloy sheets.
• Systematic variation of SPIF parameters: incremental vertical step size and tool rotational speed.
• Application of artificial neural networks (ANNs) to model and predict surface roughness parameters (Sa, Sz).

Main Results:

• Increased incremental vertical step size leads to more prominent ridges and higher Sa and Sz values in Alclad sheets.
• ANN models demonstrated good performance with R² values ranging from 0.657 to 0.979.
• Surface roughness behavior differed between Alclad sheets and non-Alclad sheets, with specific parameter dependencies observed for each.

Conclusions:

• SPIF process parameters, especially vertical step size, critically influence the surface roughness of stiffened ribs in Alclad panels.
• The findings provide insights into optimizing SPIF for aerospace components requiring specific surface finish standards.
• Distinct responses of Alclad and non-Alclad materials to forming parameters necessitate tailored process control strategies.