Study of Friction and Wear Effects in Aluminum Parts Manufactured via Single Point Incremental Forming Process Using Petroleum and Vegetable Oil-Based Lubricants.

José M Diabb Zavala,Oscar Martínez-Romero,Jaime Taha-Tijerina,Héctor Manuel Leija Gutiérrez,Alejandro Estrada-De La Vega,Alex Elías-Zúñiga

doi:10.3390/ma14143973

Abstract

This paper focuses on studying how mineral oil, sunflower, soybean, and corn lubricants influence friction and wear effects during the manufacturing of aluminum parts via the single point incremental forming (SPIF) process. To identify how friction, surface roughness, and wear change during the SPIF of aluminum parts, Stribeck curves were plotted as a function of the SPIF process parameters such as vertical step size, wall angle, and tool tip semi-spherical diameter. Furthermore, lubricant effects on the surface of the formed parts are examined by energy dispersive spectroscopy (EDS) and scanning electron microscope (SEM) images, the Alicona optical 3D measurement system, and Fourier-transform infrared spectroscopy (FTIR). Results show that during the SPIF process of the metallic specimens, soybean and corn oils attained the highest friction, along forces, roughness, and wear values. Based on the surface roughness measurements, it can be observed that soybean oil produces the worst surface roughness finish in the direction perpendicular to the tool passes (Ra =1.45 μm) considering a vertical step size of 0.25 mm with a 5 mm tool tip diameter. These findings are confirmed through plotting SPIFed Stribeck curves for the soybean and corn oils that show small hydrodynamic span regime changes for an increasing sample step-size forming process. This article elucidates the effects caused by mineral and vegetable oils on the surface of aluminum parts produced as a function of Single Point Incremental Sheet Forming process parameters.

Highlights

The effect that petroleum and vegetables oil-based lubricants have on the friction coefficient, wear, along forces, and surface roughness of metallic sheets manufactured using the single point incremental forming (SPIF) process has been investigated by considering the vertical step size, wall angle, and semispherical tool tip diameter values
It was found that during the SPIF process metallic sheets, soybean and corn oils attained the highest friction, along forces, roughness, and wear. These results are confirmed by SPIFed Stribeck curves of the soybean and corn oils in which these lubricants exhibited small hydrodynamic regime span for an increasing sample forming process
From these SPIFed Stribeck curves, it is possible to identify the values of ηU/FN from which the lubrication regime changed from a mixed film to the boundary regimes when the wall angle and SPIF depth values changed

Summary

Introduction

The single point incremental forming process (SPIF) is widely used to manufacture small batches of metallic and polymeric parts at room temperature using a CNC milling center, a support fixed to the metallic sheet to be formed, a spherical tip tool, and lubricants to reduce wear and friction force effects. In this sense, Allwood et al [1] investigated the influence that through-thickness shear (TTS) has on the forming part limit by correlating the friction effects and the tool rotational speed during SPIF. With a small mathematical model, Durante et al [4] investigated how SPIF parameters such as tool tip radius, vertical step depth, and wall angle affects the surface roughness of the formed parts

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Conclusion