Process Parameters Optimization of Thin-Wall Machining for Wire Arc Additive Manufactured Parts

Niccolò Grossi,Antonio Scippa,Giuseppe Venturini,Gianni Campatelli

doi:10.3390/app10217575

Niccolò Grossi, Antonio Scippa + Show 2 more

Open Access

https://doi.org/10.3390/app10217575

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Journal: Applied Sciences	Publication Date: Oct 27, 2020
Citations: 14	License type: CC BY 4.0

Affiliation: University of Florence

Abstract

Additive manufacturing (AM) is an arising production process due to the possibility to produce monolithic components with complex shapes with one single process and without the need for special tooling. AM-produced parts still often require a machining phase, since their surface finish is not compliant with the strict requirements of the most advanced markets, such as aerospace, energy, and defense. Since reduced weight is a key requirement for these parts, they feature thin walls and webs, usually characterized by low stiffness, requiring the usage of low productivity machining parameters. The idea of this paper is to set up an approach which is able to predict the dynamics of a thin-walled part produced using AM. The knowledge of the workpiece dynamics evolution throughout the machining process can be used to carry out cutting parameter optimization with different objectives (e.g., chatter avoidance, force vibrations reduction). The developed approach exploits finite element (FE) analysis to predict the workpiece dynamics during the machining process, updating its changing geometry. The developed solution can automatically optimize the toolpath for the machining operation, generated by any Computer Aided Manufacturing (CAM) software updating spindle speed in accordance with the selected optimization strategies. The developed approach was tested using as a test case an airfoil.

Highlights

Lightweight constructions are becoming more and more important for many industries, such as power generation, aerospace, automotive and medical technology
Strategy B was defined to minimize forced vibrations chatter-free condition; adopting such a solution leads to the selection of spindle speeds more assuming a chatter-free condition; adopting such a solution leads to the selection of spindle prone to chatter vibrations, as explained in the previous section
No detected during the strategy A machining cycle: the selection of the suitable spindle speed avoided the chatter was detected during the strategy A machining cycle: the selection of the suitable spindle speed occurrence of the phenomenon

Summary

Introduction

Lightweight constructions are becoming more and more important for many industries, such as power generation, aerospace, automotive and medical technology. Due to the strict strength and fatigue requirements, such structures are often machined from the bulk as monolithic components, removing a large amount of material to create the final product. This is achieved through intensive milling operations, removing up to 95% of the stock volume, to create the final geometry [1]. AM allows one to deposit only the material needed for the thin-walled structures, considerably reducing the material waste. This is a critical issue, especially when high cost materials are used, such as titanium or nickel-based alloys.

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