Multiobjective Optimization of Milling Parameters for Ultrahigh-Strength Steel AF1410 Based on the NSGA-II Method

Long Li,Yan Li,Zhenchao Yang,Jin Xu,Fuwu Yan

doi:10.1155/2020/8796738

Abstract

In this paper, ultrahigh-strength steel AF1410 was milled with the carbide tool, and a total of thirty experiments were performed based on central composite design (CCD) of response surface methodology. The prediction models of milling force and surface roughness are established, respectively. The influence of milling parameters (milling speed, each tooth feed, radial depth of cut, and axial depth of cut) on milling force and surface roughness is studied by ANOVA and established prediction model. Multiobjective optimization of milling parameters is accomplished based on nondominated sorting genetic algorithm II (NSGA-II) with milling force, surface roughness, and material removal rate as optimization objectives. The surface roughness, cutting force, and material removal rate are important indexes to measure the energy consumed in the process of product, the surface machining quality, and machining efficiency of processing, respectively. In order to minimize milling force and surface roughness and maximize material removal rate, NSGA-II was used for multiobjective optimization to obtain the optimal fitness value of the objective function. The NSGA-II has been applied to obtain a set of optimal combination of parameters from the Pareto-optimal solution set to enhance the machining conditions.

Highlights

Ultrahigh-strength steel has the characteristics of high strength and high toughness, which is one of the preferred materials for the important load-bearing components of ships, aviation aircraft, and military equipment [1]
Among them, cutting force, surface roughness, and material removal rate are important physical quantities in the cutting process, which has an important influence on the energy consumed in the process of product, the surface quality, and machining efficiency of processing [8,9,10,11]. erefore, cutting force and surface roughness have always been the key research target in cutting mechanism research, and they are the basic indexes for evaluating cutting process parameters
Unreasonable cutting parameters lead to large cutting force, poor surface quality, and low machining efficiency. erefore, it is necessary to select reasonable cutting parameters with the objectives of minimum surface roughness, minimum milling force, and maximum material removal rate

Summary

Introduction

Ultrahigh-strength steel has the characteristics of high strength and high toughness, which is one of the preferred materials for the important load-bearing components of ships, aviation aircraft, and military equipment [1]. To solve the problem of hard machining of ultrahighstrength steel, the key is to study the cutting mechanism and select the reasonable process parameter [6, 7]. Among them, cutting force, surface roughness, and material removal rate are important physical quantities in the cutting process, which has an important influence on the energy consumed in the process of product, the surface quality, and machining efficiency of processing [8,9,10,11]. Erefore, cutting force and surface roughness have always been the key research target in cutting mechanism research, and they are the basic indexes for evaluating cutting process parameters. Erefore, it is necessary to select reasonable cutting parameters with the objectives of minimum surface roughness, minimum milling force, and maximum material removal rate Unreasonable cutting parameters lead to large cutting force, poor surface quality, and low machining efficiency. erefore, it is necessary to select reasonable cutting parameters with the objectives of minimum surface roughness, minimum milling force, and maximum material removal rate

Objectives

Methods

Results