Hierarchical Optimal Force–Position Control of Complex Manufacturing Processes

2012 ◽  
Author(s):  
Hesam Zomorodi Moghadam ◽  
Robert G. Landers ◽  
S. N. Balakrishnan
Keyword(s):  
Cutting Force ◽  
Position Control ◽  
End Milling ◽  
Milling Process ◽  
Optimal Controller ◽  
Depth Of Cut ◽  
Force Model ◽  
Bottom Level ◽  
Reference Velocity ◽  
Micro End Milling

A hierarchical optimal controller is developed to regulate the cutting force and tool position, simultaneously, in a micro end milling process. The process is divided into two levels of decision making. The bottom level includes the measurable states, which in this work comprise the servomechanism positions. The top level includes the higher order objectives which can be derived from the bottom level objectives by an aggregation relationship. In this work the top level objective is concerned with cutting force regulation. The aggregation relations are linearized to fit into a linear optimal control problem to reduce the computational efforts. Reference velocity is calculated based on the force model, using the desired depth-of-cut and spindle speed. The proposed method is compared to a normal optimal controller without considering the top level objectives. Comparison between the two methods reveals the advantages of considering the top level objectives.

Dynamic cutting force prediction for micro end milling considering tool vibrations and run-out

2018 ◽  
Vol 233 (7) ◽  
pp. 2248-2261 ◽  
Author(s):  
Xuewei Zhang ◽  
Tianbiao Yu ◽  
Wanshan Wang
Keyword(s):  
Cutting Force ◽  
Cutting Forces ◽  
End Milling ◽  
Chip Thickness ◽  
Milling Process ◽  
Force Model ◽  
Dynamic Cutting Force ◽  
Micro End Milling ◽  
Tool Vibrations ◽  
End Milling Process

An accurate prediction of cutting forces in the micro end milling, which is affected by many factors, is the basis for increasing the machining productivity and selecting optimal cutting parameters. This paper develops a dynamic cutting force model in the micro end milling taking into account tool vibrations and run-out. The influence of tool run-out is integrated with the trochoidal trajectory of tooth and the size effect of cutting edge radius into the static undeformed chip thickness. Meanwhile, the real-time tool vibrations are obtained from differential motion equations with the measured modal parameters, in which the process damping effect is superposed as feedback on the undeformed chip thickness. The proposed dynamic cutting force model has been experimentally validated in the micro end milling process of the Al6061 workpiece. The tool run-out parameters and cutting forces coefficients can be identified on the basis of the measured cutting forces. Compared with the traditional model without tool vibrations and run-out, the predicted and measured cutting forces in the micro end milling process show closer agreement when considering tool vibrations and run-out.

Development of Cutting Force Model of Aluminum Nitride Ceramic Processed by Micro End Milling

2011 ◽  
Vol 87 ◽  
pp. 223-229 ◽  
Author(s):  
Moola Mohan Reddy ◽  
Alexander Gorin ◽  
Khaled A. Abou-El-Hossein
Keyword(s):  
Aluminum Nitride ◽  
Cutting Force ◽  
End Milling ◽  
Depth Of Cut ◽  
Force Model ◽  
Machining Parameters ◽  
Cutting Force Prediction ◽  
Force Equation ◽  
Micro End Milling ◽  
End Mills

Advanced ceramics are difficult to do machining due to brittle nature. High cutting forces will generate in the machining, which will affect the surface integrity of final product. Selection of proper machining parameters is important to obtain less cutting force. The present work deals with the study and development of a cutting force prediction model in end milling operation of Aluminum Nitride ceramic. The cutting force equation developed using Response Surface Methodology (RSM) to analyze the effect of Spindle speed, feed rate and axial depth of cut. The cutting tests were carried under dry condition using two flute square end micro grain carbide end mills.

A Mechanistic Model of Cutting Forces in Micro-End-Milling With Cutting-Condition-Independent Cutting Force Coefficients

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Han Ul Lee ◽  
Dong-Woo Cho ◽  
Kornel F. Ehmann
Keyword(s):  
Cutting Force ◽  
Cutting Forces ◽  
End Milling ◽  
Cutting Conditions ◽  
Thickness Effect ◽  
Force Model ◽  
Cutting Force Coefficients ◽  
Force Coefficients ◽  
Micro End Milling ◽  
Cutting Mechanisms

Complex three-dimensional miniature components are needed in a wide range of industrial applications from aerospace to biomedicine. Such products can be effectively produced by micro-end-milling processes that are capable of accurately producing high aspect ratio features and parts. This paper presents a mechanistic cutting force model for the precise prediction of the cutting forces in micro-end-milling under various cutting conditions. In order to account for the actual physical phenomena at the edge of the tool, the components of the cutting force vector are determined based on the newly introduced concept of the partial effective rake angle. The proposed model also uses instantaneous cutting force coefficients that are independent of the end-milling cutting conditions. These cutting force coefficients, determined from measured cutting forces, reflect the influence of the majority of cutting mechanisms involved in micro-end-milling including the minimum chip-thickness effect. The comparison of the predicted and measured cutting forces has shown that the proposed method provides very accurate results.

Optimization of Process Parameters for Cutting Force for Aluminium 7010 in CNC End Milling Process

2018 ◽  
Vol 10 (6) ◽  
Author(s):  
M. Kishanth ◽  
P. Rajkamal ◽  
D. Karthikeyan ◽  
K. Anand
Keyword(s):  
Surface Roughness ◽  
Cutting Force ◽  
Process Parameters ◽  
End Milling ◽  
Milling Process ◽  
Machining Process ◽  
Depth Of Cut ◽  
Optimization Of Process Parameters ◽  
Cnc End Milling ◽  
End Milling Process

In this paper CNC end milling process have been optimized in cutting force and surface roughness based on the three process parameters (i.e.) speed, feed rate and depth of cut. Since the end milling process is used for abrading the wear caused is very high, in order to reduce the wear caused by high cutting force and to decrease the surface roughness, the optimization is much needed for this process. Especially for materials like aluminium 7010, this kind of study is important for further improvement in machining process and also it will improve the stability of the machine.

Cutting Force Prediction for Generalized Cornering Milling Process

2011 ◽  
Vol 188 ◽  
pp. 404-409 ◽  
Author(s):  
Xue Yan ◽  
Hua Tao ◽  
D.H. Zhang ◽  
B.H. Wu
Keyword(s):  
Cutting Force ◽  
Cutting Forces ◽  
End Milling ◽  
Milling Process ◽  
Force Model ◽  
Cutting Force Model ◽  
Cutting Force Prediction ◽  
Geometric Relationship ◽  
The Mathematical Model ◽  
Good Agreement

A developed method to predict the cutting forces in end milling of generalized corners is proposed in this paper. The cornering milling process is divided into a series of cutting segments with different cutting states. The mathematical model of the geometric relationship between cutter and the corner profile is established for each segment. Cutting forces is predicted by introducing the classical cutting force model. The computational results of cutting forces are in good agreement with experimental data.

Convolution Analysis of Milling Force Pulsation

1994 ◽  
Vol 116 (1) ◽  
pp. 17-25 ◽  
Author(s):  
J.-J. Junz Wang ◽  
S. Y. Liang ◽  
W. J. Book
Keyword(s):  
Cutting Force ◽  
Density Function ◽  
Cutting Forces ◽  
End Milling ◽  
Chip Thickness ◽  
Closed Form Expression ◽  
Thickness Variation ◽  
Depth Of Cut ◽  
Force Model ◽  
Frequency Multiplication

This paper presents the establishment of a closed form expression for the dynamic forces as explicit functions of cutting parameters and tool/workpiece geometry in milling processes. Based on the existing local cutting force model, the generation of total cutting forces is formulated as the angular domain convolution of three cutting process component functions, namely the elementary cutting function, the chip width density function, and the tooth sequence function. The elemental cutting force function is related to the chip formation process in an elemental cutting area and it is characterized by the chip thickness variation, and radial cutting configuration. The chip width density function defines the chip width per unit cutter rotation along a cutter flute within the range of axial depth of cut. The tooth sequence function represents the spacing between flutes as well as their cutting sequence as the cutter rotates. The analysis of cutting forces is extended into the Fourier domain by taking the frequency multiplication of the transforms of the three component functions. Fourier series coefficients of the cutting forces are shown to be explicit algebraic functions of various tool parameters and cutting conditions. Numerical simulation results are presented in the frequency domain to illustrate the effects of various process parameters. A series of end milling experiments are performed and their results discussed to validate the analytical model.

Monitoring of Surface Roughness Based on Cutting Force and Cutting Temperature in Ball-End Milling Process by Utilizing Response Surface Analysis

2015 ◽  
Vol 799-800 ◽  
pp. 324-328
Author(s):  
Panrawee Yaisuk ◽  
Somkiat Tangjitsitcharoen
Keyword(s):  
Surface Roughness ◽  
Cutting Force ◽  
Response Surface ◽  
Feed Rate ◽  
End Milling ◽  
Cutting Temperature ◽  
Milling Process ◽  
Depth Of Cut ◽  
Tool Diameter ◽  
End Milling Process

The surface roughness is monitored using the cutting force and the cutting temperature in the ball-end milling process by utilizing the response surface analysis with the Box-Behnken design. The optimum cutting condition is obtained referring to the minimum surface roughness, which is the spindle speed, the feed rate, the depth of cut, and the tool diameter. The models of cutting force ratio and the cutting temperature are proposed and developed based on the experimental results. It is understood that the surface roughness is improved with an increase in spindle speed, feed rate and depth of cut. The cutting temperature decreases with an increase in tool diameter. The model verification has showed that the experimentally obtained surface roughness model is reliable and accurate to estimate the surface roughness.

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