Bao Sheng Wang

Prediction of Milling Force Based on Numerical Simulation of Oblique Cutting

This article presents a method to obtain the cutting force coefficients needed to predict the milling force using a mechanistic model of the milling process. A finite element model is developed and used to simulate the oblique cutting process of cutting edge discrete element for the Al6061-T6 milling. The model reflects the effects of high temperature, large strain, and strain rate to the workpiece material. Based on the simulation results, the relationship between cutting force coefficients and chip thickness is deduced, and inverse proportion models are presented. To validate the accuracy of the model, instantaneous milling force is predicted and shown to match the real measured force with satisfactory accuracy. Based on predicted milling force, the machining processing is optimized.

Two-Step Identification of Instantaneous Cutting Force Coefficients and Cutter Runout

Cutting force coefficients and cutter runout parameters are the key factors for accurate prediction of instantaneous milling forces. A new two-step identification method is presented to calibrate them in end milling. Based on analyzing effects of cutter runout on milling forces, a method of extracting nominal milling forces from measured milling forces is proposed. By calibrating average cutting force coefficients and corresponding average chip thickness, an approach to evaluate the instantaneous cutting force coefficients is proposed. Then, an iterative method is presented to identify cutter runout, and the procedure is also given in detail. Milling tests are performed to test the proposed method, and validity of the identification approach is proved by a good agreement between predicted results and experimental results.

Hybrid Flow-Shop Scheduling Method and Simulation Based on Adaptive Genetic Algorithm

The n-job, k-stage hybrid flow shop problem is one of the general production scheduling problems. Hybrid flow shop (HFS) problems are NP-Hard when the objective is to minimize the makespan .The research deals with the criterion of makespan minimization for the HFS scheduling problems. In this paper we present a new encoding method so as to guarantee the validity of chromosomes and convenience of calculation and corresponding crossover and mutation operators are designed for optimum sequencing. The simulation results show that the Sequence Adaptive Cross Genetic Algorithm (SACGA) is an effective and efficient method for solving HFS Problems.

Control System for Digital Forming Machine of Lost Foam Based on PMAC

Control system is the key factor for performance of digital forming machine. To meet different needs, an open NC system structure is proposed based on PMAC. Selection of servo motor is analyzed, and hardware of control system is established. Software composed of multiple modules is developed with VC++, and also communication between PC and PMAC is realized. Furthermore, a method to optimize manufacturing process and interpolation path is presented according to characteristics of lost foam machining. Simulation and experiment are carried out, and the results confirm that the control system is excellent.

Experimental Research on Cutting Temperature of AISI 1045 in High Speed Milling Process

The aim of this paper is to investigate the time dependence distribution of workpiece cutting temperature in milling process. An experimental system used to achieve a measurement of cutting temperature in high speed milling is designed by use of the thermocouple and infrared thermal imager. The general regularity of temperature distribution is concluded, and the influence of the process variables such as cutting speed, cutting depth, etc. on the temperature distribution was investigated in detail. All the experiment results can be effective used to develop a new non-contact soft-sensing method for high speed cutting temperature prediction.

The Coupling Thermal and Mechanical Analysis of Machining Aluminum Alloy Work-Piece Based on FEM

The Cutting force and cutting temperature are the important factors which can affect the quality and accuracy of the aluminum alloy work-pieces. Based on the theoretical analysis of the cutting force and cutting temperature, the three-dimensional Finite Element Model (FEM) with the overall tool is established. The corresponding results of the digital simulation were researched, and the cutting force and cutting temperature were analyzed. The cutting temperature and cutting force changes were compared by altering the axial depth of cut and the feed rate. Keywords: Oblique cutting model, Finite Element Method (FEM), Cutting temperature, Cutting force, Aluminum alloy work-piece

Efficient Prediction of Runout Parameters in End Milling Operation

This paper aims at studying a method to identify the cutter runout parameters for end milling. An analytical cutting force model for end milling is proposed to predict cutting force. The cutting force is separated into a nominal component independent of the cutter runout and a perturbation component induced by the cutter runout. Using the cutting force acting on the and directions to calculate the difference between the cutting radius of the adjacent tooth. Then runout parameters are obtained after a series of data processing. The simulation and the experimented results are made to validate the presented methods.

Modeling and Experiment of the Cutting Force for Aluminium Alloy Work-Piece

The application of Finite Element Method (FEM) in cutting force model for Aluminium alloy work-piece is useful to reduce the production costs and shorten the experimental period. Firstly, the theoretical model of the orthogonal cutting and the oblique cutting are analyzed in this paper. And then, the corresponding finite element models are theoretically constructed. By comparing the results, the following conclusions are drawn: with the increase of the cutting thickness, the cutting force increasing is in an enhancement tendency. The oblique cutting model of overall tool is more conductive to the subsequent runout and the flutter analysis.

Influence of the Process Variables on the Temperature Distribution in AISI 1045 Turning

High-speed metal cutting processes can cause extremely rapid heating of the work material. Temperature on the machined surface is critical for surface integrity and the performance of a precision component. However, the temperature of a machined surface is challenging for in-situ measurement.So, the finite element(FE) method used to analyze the unique nonlinear problems during cutting process. In terms of heat-force coupled problem, the thermo-plastic FE model was proposed to predict the cutting temperature distribution using separated iterative method. Several key techniques such as material constitutive relations, tool-chip interface friction and separation and damage fracture criterion were modeled. Based on the updated Lagrange and arbitrary Lagrangian-Eulerian (ALE) method, the temperature field in high speed orthogonal cutting of carbon steel AISI-1045 were simulated. The simulated results showed good agreement with the experimental results, which validated the precision of the process simulation method. Meanwhile, the influence of the process variables such as cutting speed, cutting depth, etc. on the temperature distribution was investigated.

Experiment of Temperature Field for High Speed Orthogonal Turning

An experimental system used for temperature measurement is designed by the K-type thermocouple thermometry to achieve a direct measurement of cutting temperature in high speed orthogonal turning. The general regularity of temperature distribution is concluded, and the corresponding influences of cutting speed and cutting depth on the maximum temperature value are discussed in detail. Experimental data and simulating results are comparative analyzed to demonstrate the feasibility and correctness of Finite Element Method (FEM) model simulation and analytical solution. The verified model of temperature field can be applied to develop an effective non-contact soft-sensing method for high speed cutting temperature.