Modeling and Conventional/Adaptive PI Control of a Lathe Cutting Process

1988 ◽  
Vol 110 (4) ◽  
pp. 350-354 ◽  
Author(s):  
M. Tomizuka ◽  
S. Zhang
Keyword(s):  
Cutting Force ◽  
Chip Thickness ◽  
Pi Controller ◽  
Experimental Results ◽  
Cutting Process ◽  
Laboratory Evaluation ◽  
Control Scheme ◽  
Identification Technique ◽  
Geometrical Consideration ◽  
Good Agreement

A mathematical model for predicting dynamics between the feedrate and cutting force in the lathe cutting process is presented. The model comes from combinations of a parameter identification technique and geometrical consideration for chip thickness time variation. The model prediction of transient responses is in good agreement with the experimental results. The model is used for tuning a PI controller for regulating the cutting force as well as to show performance limitations of the conventional PI controller. A simple adaptive control scheme that makes use of the model structure is proposed. Experimental results from laboratory evaluation of the proposed controllers are presented.

A Micromilling Experimental Study on AISI 4340 Steel

2009 ◽  
Vol 407-408 ◽  
pp. 335-338 ◽  
Author(s):  
Jin Sheng Wang ◽  
Da Jian Zhao ◽  
Ya Dong Gong
Keyword(s):  
Experimental Study ◽  
Surface Roughness ◽  
Cutting Force ◽  
Spectrum Analysis ◽  
Chip Thickness ◽  
Experimental Results ◽  
Minimum Chip Thickness ◽  
Aisi 4340 Steel ◽  
4340 Steel ◽  
Aisi 4340

A micromilling experimental study on AISI 4340 steel is conducted to understand the micromilling principle deeply. The experimental results, especially on the surface roughness and cutting force, are discussed in detail. It has been found the minimum chip thickness influences the surface roughness and cutting force greatly. Meanwhile, the material elastic recover induces the increase of the axial micromilling force. The average cutting force and its spectrum analysis validate the minimum chip thickness approximation of AISI 4340 is about 0.35μm.

scholarly journals Cutting Force in Stone Machining by Diamond Disk

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
S. Turchetta
Keyword(s):  
Cutting Force ◽  
Process Parameters ◽  
Chip Thickness ◽  
Empirical Models ◽  
Cutting Conditions ◽  
Cutting Process ◽  
Diamond Disk ◽  
Cutting Energy ◽  
Removal Process ◽  
Selection Of

Stone machining by diamond disk is a widespread process to manufacture standard products, such as tiles, slabs, and kerbs. Cutting force and energy may be used to monitor stone machining. Empirical models are required to guide the selection of cutting conditions. In this paper, the effects of cutting conditions on cutting force and cutting energy are related to the shape of the idealized chip thickness. The empirical models developed in this paper can be used to predict the variation of the cutting energy. Therefore these models can be used to guide the selection of cutting conditions. The chip generation and removal process has been quantified with the intention of assisting both the toolmaker and the stonemason in optimising the tool composition and cutting process parameters, respectively.

Finite Element Analysis of Cutting Forces in High Speed Machining

2006 ◽  
Vol 532-533 ◽  
pp. 753-756 ◽  
Author(s):  
Jun Zhao ◽  
Xing Ai ◽  
Zuo Li Li
Keyword(s):  
Finite Element ◽  
Cutting Force ◽  
Cutting Forces ◽  
High Speed ◽  
Fem Simulation ◽  
Chip Thickness ◽  
Cutting Conditions ◽  
Cutting Process ◽  
Undeformed Chip Thickness ◽  
High Speed Cutting

The Finite Element Method (FEM) has proven to be an effective technique to investigate cutting process so as to improve cutting tool design and select optimum cutting conditions. The present work focuses on the FEM simulation of cutting forces in high speed cutting by using an orthogonal cutting model with variant undeformed chip thickness under plane-strain condition to mimic intermittent cutting process such as milling. High speed cutting of 45%C steel using uncoated carbide tools are simulated as the application of the proposed model. The updated Lagrangian formulation is adopted in the dynamic FEM simulation in which the normalized Cockroft and Latham damage criterion is used as the ductile fracture criterion. The simulation results of cutting force components under different cutting conditions show that both the thrust cutting force and the tangential cutting force increase with the increase in undeformed chip thickness or feed rate, whereas decrease with the increase in cutting speed. Some important aspects of modeling the high speed cutting are discussed as well to expect the future work in FEM simulation.

Force control in turning based on robust PI controller design

1997 ◽  
Vol 211 (2) ◽  
pp. 165-175 ◽  
Author(s):  
L Harder ◽  
A J Isaksson
Keyword(s):  
Cutting Force ◽  
Time Constant ◽  
Force Control ◽  
Controller Design ◽  
Pi Controller ◽  
Internal Model Control ◽  
Time Variable ◽  
Cutting Process ◽  
Process Gain ◽  
Rough Turning

Real-time cutting force control is a very straightforward way to improve safety, performance and quality in rough turning operations. The main problem in controller design for force control is to achieve robustness. Several time-variable process parameters, such as the depth of cut, the spindle rotational speed and the specific cutting force, directly affect the closed-loop system gain and time constant. In this paper, two approaches to robust PI (proportional integral) controller design based on the internal model control (IMC) method are presented. The first approach treats the cutting process as a first-order system with a time- variable gain. By designing for highest process gain, the controller becomes robust, but perhaps a bit sluggish for the lower range of process gain. In the second approach, the cutting process is linearized by introducing non-linear transformations. In this way, the design may be based on a constant-gain system and the time-variable parameters may be considered as additive disturbances. This controller is somewhat faster than the first approach and shows almost identical behaviour over the entire operating range. Both controllers incorporate, in addition, simple parameter adaptation by gain scheduling with respect to spindle speed variations, in order to handle variations in the process time constant. The work presented in this paper shows that it is possible to achieve robust force control in turning using the common PI controller.

Time-Domain Simulation on Plunge Milling Ti-6Al-4V

2012 ◽  
Vol 500 ◽  
pp. 94-98
Author(s):  
Xu Da Qin ◽  
Lin Jing Gui ◽  
Hao Jia ◽  
Cui Lu ◽  
Hao Li
Keyword(s):  
Cutting Force ◽  
Time Domain ◽  
Chip Thickness ◽  
Time Domain Simulation ◽  
Vibration System ◽  
Plunge Milling ◽  
Milling Force ◽  
Simulation Results ◽  
Significant Attention ◽  
Good Agreement

The research of cutting force and vibration has been gaining significant attention to improve machining efficiency and tool life in processing metals. In this paper, the plunge milling system is reduced to 3-DOF vibration system, and dynamical theoretical model and instantaneous undeformed chip thickness models are established based on dividing cutter tooth into finite number of small differential elements in the radial direction and discrete time domain. Based on regenerative chatter theory, the cutting force and vibration can be simulated by numerical algorithm. Compared the simulation results with experiments data, the milling force and vibration have a good agreement, which testify the correction of those models

FEM Simulation on the Effect of Cutting Parameters in the Driven Rotary Cutting

2014 ◽  
Vol 625 ◽  
pp. 564-569 ◽  
Author(s):  
Wataru Takahashi ◽  
Hiroyuki Sasahara ◽  
Hiromasa Yamamoto ◽  
Yuji Takagi
Keyword(s):  
Cutting Force ◽  
Flow Direction ◽  
Fem Simulation ◽  
Chip Thickness ◽  
Cutting Parameters ◽  
Experimental Results ◽  
Tool Temperature ◽  
Chip Flow ◽  
Rotary Cutting ◽  
Machining Parameter

In this paper, the influence of machining parameter in the driven rotary cutting was examined by using finite element simulation. Three dimensional modeling of rotary cutting of Inconel 718 was conducted and then cutting force, temperature distribution of chip and tool, chip thickness and its flow direction were analyzed. Then, the effect of the tool rotation speed was mainly focused on. When peripheral speed of the rotating tool increased, resultant cutting force decreased and the chip flow direction inclined to the tool rotating direction. Then high temperature region of chip became large. It was also shown that tool temperature on the driven rotary cutting was lower than that of the conventional turning. FEM simulation results were compared with the experimental results. As a result, the resultant cutting force, chip flow direction and the tool temperature of the experimental results and the analysis results showed the same trend.

Machining Forces: Some Effects of Tool Vibration

1965 ◽  
Vol 7 (2) ◽  
pp. 152-162 ◽  
Author(s):  
P. W. Wallace ◽  
C. Andrew
Keyword(s):  
Thrust Force ◽  
Chip Thickness ◽  
Experimental Results ◽  
Tool Vibration ◽  
Undeformed Chip Thickness ◽  
Speed Range ◽  
Theoretical Predictions ◽  
Thrust Forces ◽  
Good Agreement ◽  
Made In

When tool vibration occurs during machining both the undeformed chip thickness and the cutting forces have oscillating components. An examination of previous work reveals that both the relative phases and amplitudes of the oscillating forces and the oscillating undeformed chip thickness can be affected appreciably by changes in frequency. The explanations for this behaviour which have been put forward are not entirely consistent with previous experimental evidence. In the present work an analysis of the thrust forces occurring during tool vibration is proposed. The analysis is based on the assumption that there are two components to the oscillating thrust force: (1) a component proportional to, and in phase with, the oscillations in undeformed chip thickness and (2) a component, caused by contact between a small area of the tool flank and the freshly cut work surface, which leads the oscillation in undeformed chip thickness by 90°. Experimental results are presented which validate the assumptions made in the analysis. On applying the analysis to present and past experimental results, there is good agreement between theory and experiment when cutting at sufficient speed to prevent the formation of a substantial built-up edge: when cutting within the built-up edge speed range the theoretical predictions are less satisfactory, though still qualitatively correct. The results also show that changes in undeformed chip thickness have a smaller effect on the tool forces under vibratory conditions than under steady conditions.

Predictions of Cutting Force and Tool Wear in Gear Power Skiving

2021 ◽  
Author(s):  
Zongwei Ren ◽  
Zhenglong Fang ◽  
Takuhiro Arakane ◽  
Toru Kizaki ◽  
Yannan Feng ◽  
...  
Keyword(s):  
Tool Wear ◽  
Cutting Force ◽  
Cutting Tool ◽  
Chip Thickness ◽  
Rake Angle ◽  
Parametric Modeling ◽  
Cutting Conditions ◽  
Cutting Process ◽  
Rake Face ◽  
Power Skiving

Abstract Power skiving is a promising method that can enhance the efficiency of gear machining. The machining mechanism is complicated due to several factors, such as the continuous variation in the rake angle and undeformed chip thickness. The tool wear process is also difficult to be evaluated due to the constantly varying in cutting conditions. Hence, to make a comprehensive understanding of the cutting process, we proposed a parametric modeling process based on the kinematics of power skiving. In this model, the undeformed cutting chip was calculated in each pass and shows the consistency with deformed cutting chip in experiments. The effective rake angle and undeformed cutting chip thickness were defined, calculated, and displayed on undeformed cutting chip for a better understanding of the cutting process. The cutting force and tool crater wear were calculated by estimating the distribution of the stress and temperature on the rake face of the cutting tool. Multiple radial-feed experimental evaluations were conducted with the gears of construction vehicles. In the results, the predicted margin of the absolute error of the normal force on the rake face was under 5% in every pass. The wear distribution on the rake face is consistent with the superimposed tool-chip contact area. The results show high potential for the optimization of the cutting tool or cutting conditions in gear power skiving.

Non-Free Cutting and Its Degree of Freedom Confinement

1999 ◽  
Vol 121 (1) ◽  
pp. 150-153 ◽  
Author(s):  
H. Shi ◽  
X. Wang ◽  
Tao Lu
Keyword(s):  
General Theory ◽  
Cutting Force ◽  
Cutting Forces ◽  
Cutting Tool ◽  
Minimum Energy ◽  
Cutting Tools ◽  
Synthesis Method ◽  
Degree Of Freedom ◽  
Cutting Process ◽  
Good Agreement

Plunge-turning processes of round-edged cutters is analyzed and its cutting force modeled in the light of a general theory of non-free cutting developed by the authors. In this study the whole cutting tool is treated as a combination of a series of Elementary Cutting Tools (ECTs). Due to the non-linearity of chip-ejection interference among all the ECTs the total cutting force of the whole cutter, however, cannot be calculated by simply superposing the incremental cutting forces generated by all the ECTs. A Non-Linear Synthesis Method (NLSM) is therefore suggested for modeling this non-free cutting force. The main feature of the method is that the chip-ejection interference is under consideration and modeled on the basis of the Principle of Minimum Energy (PME). Good agreement between the predicted and measured main cutting forces is identified. Furthermore, a Coefficient of Non-Free Cutting (CNFC) is applied to quantitatively indicate the strength of chip-ejection interference among the ECTs and the degree of freedom confinement of the cutting process.

Inverse identification of modified Johnson–Cook model for cutting titanium alloy Ti6Al4V using firefly algorithm

2019 ◽  
Vol 234 (3) ◽  
pp. 584-599 ◽  
Author(s):  
Jinhua Zhou ◽  
Junxue Ren ◽  
Yong Jiang
Keyword(s):  
Titanium Alloy ◽  
Cutting Force ◽  
Firefly Algorithm ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Cutting Process ◽  
Zone Model ◽  
Serrated Chip ◽  
Titanium Alloy Ti6al4v ◽  
Cook Model

The original Johnson–Cook equation fails to describe the significant thermal softening phenomenon of flow stress in cutting process of titanium alloy Ti6Al4V. Recently, some researchers developed some modified Johnson–Cook models of Ti6Al4V by introducing some additional parameters. But effective parameter identification method is unavailable in those research works. In this work, an inverse approach is developed to determine the additional parameters. A modified Johnson–Cook model with the hyperbolic tangent function is adopted, in which four unknown parameters need to be determined. The parameter assessment is taken as an optimization process based on the unequal division parallel-sided shear zone model. Along with the measured cutting force and chip thickness, the firefly algorithm is introduced to search for the parametric optimal solution. Those four parameters are determined when the difference between the predicted and experimental effective stress at shear plane reaches its minimum. The identified constitutive model is subsequently verified by finite element simulation of orthogonal cutting process, and compared with previous different material models. With the identified modified Johnson–Cook model, the serrated chip is observed in all the simulations. A good agreement between verification experiments and simulations is achieved. An acceptable prediction accuracy with an error of 10.28% on cutting force and an error of 18.12% on chip size is achieved.

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