Characterizing the Effect of 319 Aluminum Microstructure on Machinability: Part 2 — Model Validation

Author(s):  
Xuefei Hu ◽  
John W. Sutherland ◽  
James M. Boileau

In Part 1 of this paper, a machining force model was developed based on an enhanced version of Zheng’s Continuum Mechanics model that incorporates microstructural effects. Machining experiments identified Secondary Dendrite Arm Spacing (SDAS) as a significant microstructure feature of 319 aluminum in terms of machinability. A new material constitutive relationship that incorporates SDAS microstructure effects on the flow stress was proposed. In this part of the paper, disk turning tests are performed to simulate the orthogonal cutting process. The cutting forces obtained from some of these tests are used in concert with an inverse form of the continuum mechanics machining model to estimate the parameters in the material constitutive equation. The enhanced continuum mechanics orthogonal cutting model is then applied to predict cutting forces when machining Al319. Comparison of the model predicted and experimentally acquired cutting forces is demonstrated to show good agreement.

2010 ◽  
Vol 97-101 ◽  
pp. 1961-1964 ◽  
Author(s):  
Wei Guo Wu ◽  
Gui Cheng Wang ◽  
Chun Gen Shen

In this work, the prediction and analysis of cutting forces in precision turning operations is presented. The model of cutting forces is based on the oblique cutting force model which was rebuilt by two coordinate conversions from the orthogonal cutting model. Then the cutting field in precision turning was divided into two fields which are characterized as curve change and linear change on cutter edge and they were modeled respectively. Cutting field of cutter nose was modeled by differential method and its cutting force distribution is predicted by the proposed method. The predicted results for the cutting forces are in agreement with the experimental results under a variety of operation variables, including changes in the depths of cut and in the feedrate.


2005 ◽  
Vol 128 (3) ◽  
pp. 767-774 ◽  
Author(s):  
Yuliu Zheng ◽  
Xuefei Hu ◽  
John W. Sutherland

In Part 1 of this paper, a continuum mechanics model of the orthogonal cutting process was developed based on finite deformation theory. In this part of the paper, constitutive equations for O1 and L6 tool steels are developed using the results from split Hopkinson pressure bar tests. Statistically designed orthogonal cutting experiments are conducted to secure process results across a range of cutting conditions. The continuum mechanics model established in Part 1 of this paper is used to simulate all the cutting tests. All the model outputs are calculated and compared with the corresponding cutting experiment results. Good agreement is observed between the model predictions and the experimental results. The continuum mechanics model is successfully used to predict the cutting force, shear angle, and temperature.


2021 ◽  
Author(s):  
Shoichi Tamura ◽  
Takashi Matsumura

In manufacturing, hybrid systems of metal additive manufacturing and cutting in the same platform have been attractive in terms of low volume production of customized parts, complex shape, and fine surface finish. Milling is conducted to finish rough surface fabricated in additive process. The fundamental machinability of the additive workpiece should be studied because the material properties are different from metals produced in the conventional process. The paper discusses the cutting forces in milling of AISI 420 stainless steel fabricated in additive process. The cutting tests were conducted to measure the cutting forces and the chip morphologies for tool geometries. The cutting forces were also analyzed in an energy-based force model. In the analysis model, three-dimensional chip flow is interpreted as a piling up of orthogonal cuttings in the planes containing the cutting velocities and the chip flow velocities, where the cutting model is made by the orthogonal cutting data acquired in cutting tests. The chip flow direction is determined to minimize the cutting energy. The cutting forces, then, were predicted in the determined chip flow model. The cutting force model was validated in comparison of simulated forces with the actual ones.


Author(s):  
Ashwani Pratap ◽  
Karali Patra

Abstract This work presents an analytical cutting force modeling for micro-slot grinding. Contribution of the work lies in the consideration of both primary and secondary tool surface interactions with the work surface as compared to the previous works where only primary tool surface interaction was considered during cutting force modeling. Tool secondary surface interaction with workpiece is divided into two parts: cutting/ ploughing by abrasive grits present in exterior margin of the secondary tool surface and sliding/adhesion by abrasive grits in the inner margins of the secondary tool surface. Orthogonal cutting force model and indentation based fracture model is considered for cutting by both the abrasives of primary tool surface and the abrasives of exterior margin on the secondary surface. Asperity level sliding and adhesion model is adopted to solve the interaction between the workpiece and the interior margin abrasives of secondary tool surface. Experimental measurement of polycrystalline diamond tool surface topography is carried out and surface data is processed with image processing tools to determine the tool surface statistics viz., cutting edge density, grit height distribution and abrasive grit geometrical measures. Micro-slot grinding experiments are carried out on BK7 glass at varying feed rate and axial depths of cut to validate the simulated cutting forces. Simulated cutting forces considering both primary and secondary tool surface interactions are found to be much closer to the experimental cutting forces as compared to the simulated cutting forces considering only primary tool surface interaction.


Author(s):  
Richard B. Mindek ◽  
Joseph M. Guerrera

Educating engineering students in the appropriate methods for analyzing and problem solving fundamental manufacturing processes is a challenge in undergraduate engineering education, given the increasingly limited room in the curriculum as well as the limited time and resources. Although junior and senior level laboratory courses have traditionally been used as a pedagogical platform for conveying this type of knowledge to undergraduate students, the broad range of manufacturing topics that can be covered along with the limited time within a laboratory course structure has sometimes limited the effectiveness of this approach. At the same time, some undergraduate students require a much deeper knowledge of certain manufacturing topics, practices or research techniques, especially those who may already be working in a manufacturing environment as part of a summer internship or part-time employment. The current work shows how modeling, actual machining tests and problem solving techniques were recently used to analyze a manufacturing process within a senior design project course. Specifically, an Instantaneous Rigid Force Model, originally put forward by Tlusty (1,2) was validated and used to assess cutting forces and the ability to detect tool defects during milling operations. Results from the tests showed that the model accurately predicts cutting forces during milling, but have some variation due to cutter vibration and deflection, which were not considered in the model. It was also confirmed that a defect as small as 0.050 inches by 0.025 inches was consistently detectable at multiple test conditions for a 0.5-inch diameter, 4-flute helical end mill. Based on the results, it is suggested that a force cutting model that includes the effect of cutter vibration be used in future work. The results presented demonstrate a level of knowledge in milling operations analysis beyond what can typically be taught in most undergraduate engineering laboratory courses.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Haoqiang Zhang ◽  
Xibin Wang ◽  
Siqin Pang

In microdrilling, because of lower feed, the microdrill cutting edge radius is comparable to the chip thickness. The cutting edges therefore should be regarded as rounded edges, which results in a more complex cutting mechanism. Because of this, the macrodrilling thrust modeling is not suitable for microdrilling. In this paper, a mathematical modeling to predict microdrilling thrust is developed, and the geometric characteristics of microdrill were considered in force models. The thrust is modeled in three parts: major cutting edges, secondary cutting edge, and indentation zone. Based on slip-line field theory, the major cutting edges and secondary cutting edge are divided into elements, and the elemental forces are determined by an oblique cutting model and an orthogonal model, respectively. The thrust modeling of the major cutting edges and second cutting edge includes two different kinds of processes: shearing and ploughing. The indentation zone is modeled as a rigid wedge. The force model is verified by comparing the predicted forces and the measured cutting forces.


Author(s):  
Shengqi Zhang ◽  
John S. Strenkowski

An Eulerian model is described that simulates orthogonal cutting of unidirectional fiber-reinforced polymer (FRP) composites. The continuous finite element method (FEM) and the discontinuous Galerkin (DG) method are combined to solve the governing equations. A progressive damage model is implemented to predict subsurface damage in the composite. A correction factor that accounts for fiber curvature is included in the model that incorporates the influence of fiber bending. It was found that fiber orientation has a dominant influence on both the cutting forces and subsurface damage. Good agreement was found between predicted cutting forces and subsurface damage and published experimental observations.


1998 ◽  
Vol 120 (1) ◽  
pp. 49-56 ◽  
Author(s):  
B. K. Ganapathy ◽  
I. S. Jawahir

The present tendency towards increased automation of metal cutting operations has resulted in a need to develop a model for the chip breaking process. Conventional cutting force models do not have any provision for the study of chip breaking since they assume a continuous mode of chip formation, where the contact action of the free-end of the chip is ignored in all analyses. The new cutting force model proposed in this work incorporates the contact force developed due to the free-end of the chip touching the workpiece, and is applicable to the study of two-dimensional chip breaking in orthogonal machining. Orthogonal cutting tests were performed to obtain two-dimensional chip breaking. The experimentally measured cutting forces show a good correlation with the estimated cutting forces using the model. Results show that the forces acting on the chip vary within a chip breaking cycle and help identify the chip breaking event.


2012 ◽  
Vol 268-270 ◽  
pp. 422-425
Author(s):  
Mu Lan Wang ◽  
Jun Ming Hou ◽  
Bao Sheng Wang ◽  
Wen Zheng Ding

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.


2017 ◽  
Vol 882 ◽  
pp. 61-65
Author(s):  
Fadi Kahwash ◽  
Islam Shyha ◽  
Alireza Maheri

This paper presents an empirical force model quantifying the effect of fibre volume fraction and fibre orientation on the cutting forces during orthogonal cutting of unidirectional composites. Glass fibre plates and high speed steel cutting tools are used to perform orthogonal cutting on shaping machine whereas cutting forces are measured using platform force dynamometer. The analysis of forces shows almost linear dependency of cutting forces on the fibre content for both cutting and thrust forces. High dependency of cutting forces is also observed on fibre orientation with high percentage contribution ratio (up to 95.31%). Lowest forces corresponded to 30o and highest to 90o fibre orientation. Multivariate regression technique is used to construct the empirical model.


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