Dynamic model of cutting process with modulated spindle speed

2012 ◽  
Author(s):  
R. Rusinek ◽  
K. Kecik ◽  
J. Warminski ◽  
A. Weremczuk
Keyword(s):  
Dynamic Model ◽  
Spindle Speed ◽  
Cutting Process

The Effects of Static Frictions on the Drilling Process of Hammer-Drill System

2005 ◽  
Author(s):  
Y. Xu ◽  
K. L. Yung ◽  
S. M. Ko
Keyword(s):  
Dynamic Model ◽  
Cutting Process ◽  
Drilling Process ◽  
Normal Impact ◽  
New Model ◽  
Mars Mission ◽  
Dynamic Analyses ◽  
Drill System

Static frictions are neglected in many dynamic analyses mainly due to inappropriate modeling of them. A new dynamic model describing the nonlinear and discrete features of static frictions is proposed in this paper. Using the new model, the drilling process of the hammer-drill system utilized in the EAS’ Mars mission is analyzed. It is shown that most important functions of the hammer-drill system are realized by static frictions, which were not observed before the introduction of the new model of static frictions. Static frictions provide the torsional force on the drill and make the normal impact happen before the rotation, which is critical to the efficiency of the cutting process of the hammer-drill system.

Some Applications of State and Parameter Estimation to Machine Tool Problems: I—Applications of Nonsequential Estimation

1970 ◽  
Vol 92 (3) ◽  
pp. 633-646 ◽  
Author(s):  
Russell F. Henke
Keyword(s):  
Machine Tool ◽  
Dynamic Model ◽  
High Speed ◽  
Metal Cutting ◽  
Sequential Estimation ◽  
Cutting Process ◽  
Damping Factor ◽  
Process Data ◽  
Identification Schemes ◽  
On Line

A general introduction to the area of off-line and on-line identification of systems is given, and applications of these techniques to machine tool problems, especially adaptive or optimal control, are discussed. The problem of identifying the dynamic model of the metal cutting process is given special emphasis. A general formulation of the nonsequential or off-line estimation problem is presented using state variable notation, so that nonlinearities and time varying parameters may be present. Two techniques tailored to the use of the high-speed digital computer are developed to solve this general problem. The first utilizes a direct multivariable search to match the output, of an assumed dynamic model to actual experimental observations in a least squares sense. The second method uses a modified quasilinearization procedure. Controlled digital experiments are used to refine and test the proposed techniques. The two algorithms are then applied to actual experimental cutting process data. Estimates of the cutting stiffness and damping factor in the dynamic model of the cutting process are obtained, thus demonstrating the effectiveness of the developed nonsequential identification schemes, and showing that the assumed linear dynamic model adequately represents the cutting process. A later paper will consider sequential estimation applications.

A Control System for Chatter Avoidance by Ramping the Spindle Speed

1998 ◽  
Vol 120 (4) ◽  
pp. 674-683 ◽  
Author(s):  
E. Soliman ◽  
F. Ismail
Keyword(s):  
Control System ◽  
High Speed ◽  
Spindle Speed ◽  
Cutting Process ◽  
Statistical Indicator ◽  
Speed Range ◽  
Force Signal ◽  
On Line ◽  
Full Immersion ◽  
R Value

This paper presents a new control system for chatter avoidance in milling. The control system monitors the cutting process using a statistical indicator named the R-value which is computed from the cutting force signal. When chatter is detected, the control system ramps the spindle speed in search of a speed at which chatter ceases. The system does not involve time consuming computations and therefore is suitable for on-line implementation. Also, it does not interrupt the cutting process by halting the feedrate or the spindle speed. Simulations showed that the control system has a significant chatter avoidance potential in the high speed range, and also for partial and full immersion cuts. The system was implemented successfully to avoid chatter in slotting and half immersion down milling.

Avoiding Instability on the Milling of Parts with Thin Features

2006 ◽  
Vol 526 ◽  
pp. 37-42 ◽  
Author(s):  
Francisco Javier Campa ◽  
Luis Norberto López de Lacalle ◽  
S. Herranz ◽  
Aitzol Lamikiz ◽  
A. Rivero
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Spindle Speed ◽  
Depth Of Cut ◽  
Test Device ◽  
High Speed Milling ◽  
Thin Walls ◽  
Chatter Vibrations ◽  
The Stability ◽  
Selection Of

In this paper, a 3D dynamic model for the prediction of the stability lobes of high speed milling is presented, considering the combined flexibility of both tool and workpiece. The main aim is to avoid chatter vibrations on the finish milling of aeronautical parts, which include thin walls and thin floors. In this way the use of complex fixtures is eliminated. Hence, an accurate selection of both axial depth of cut and spindle speed can be accomplished. The model has been validated by means of a test device that simulates the behaviour of a thin floor.

scholarly journals Modelling for Contact Stress Control in Automated Polishing

2021 ◽  
Author(s):  
Avery Roswell
Keyword(s):  
Dynamic Model ◽  
Contact Stress ◽  
Tool Path ◽  
Coupling Effect ◽  
Open Loop ◽  
Friction Torque ◽  
Spindle Speed ◽  
Work Piece ◽  
Loop Control ◽  
System A

This research pertains to the initial steps in designing an end-effector for automated polishing, and focuses on: (1) controlling the contact stress on the work-piece surface, and (2) controlling the torque or the spindle speed to overcome the friction torque (hence, preventing the tool from stalling) and maintain a desired polishing rate. By forming a contact stress model, parameter planning is achieved and then augmented to already existing tool path data. A dynamic model for the particular end-of-arm tooling used is derived. The dynamic model clearly shows a coupling effect between the pressure and spindle speed of the system. A closed-loop control scheme, designed to eliminate the coupling is then introduced. The effectiveness of parameter planning is assessed through open loop testing. The parameter planning method allows polishing without significantly changing the part profile, whereas, without the parameter planning, the part profile is changed considerably.

The Impact of the Cutting Process on the Dimensional Accuracy of Expendable Patterns

2014 ◽  
Vol 971-973 ◽  
pp. 291-294
Author(s):  
Dong Xia Yang ◽  
Zhong De Shan ◽  
Feng Liu ◽  
Zhi Quan Zhang ◽  
Xiang Yu Song
Keyword(s):  
Feed Rate ◽  
Dimensional Accuracy ◽  
Spindle Speed ◽  
Cutting Process ◽  
Machining Accuracy ◽  
Cutting Depth ◽  
Reasonable Range ◽  
The Impact ◽  
Expendable Pattern ◽  
Selection Of

In this work, a systematic study was carried out on the cutting process of expendable pattern, and the impact of process parameters, such as spindle speed, feed rate and cutting depth on the dimensional accuracy of expendable pattern was discussed. The results show that the dimensional accuracy at length and width directions of expendable pattern is less affected by the cutting process, while the machining accuracy at height direction of expendable pattern is greatly influenced by the cutting process. With the increase of spindle speed, the height error reduced undulately; with the increase of feed rate, the height error increases gradually; the selection of cutting depth has a reasonable range, above or below this range will cause the increase of the dimension error.

An Investigation of Variable Spindle Speed Face Milling for Tool-Work Structures With Complex Dynamics, Part 2: Physical Explanation

1997 ◽  
Vol 119 (3) ◽  
pp. 273-280 ◽  
Author(s):  
R. Radulescu ◽  
S. G. Kapoor ◽  
R. E. DeVor
Keyword(s):  
Forced Vibration ◽  
Cutting Forces ◽  
Complex Dynamics ◽  
Spindle Speed ◽  
Constant Speed ◽  
Cutting Process ◽  
Variable Speed ◽  
Work System ◽  
Machining Operations ◽  
Work Done

Part 2 of this paper focuses on the explanation, both on theoretical grounds and through model simulations, of why the technique of variable spindle speed machining is an effective tool for increasing the quality and productivity of machining operations. In particular, Part 2 explains why, by disturbing the regenerative and forced vibration excitation frequencies which generate large amplitudes of vibration during constant speed machining, variable speed machining has the potential to reduce the vibration of the tool-work system and be robust with respect to the cutting process dynamics. The explanation is based on the work done by the cutting forces, the chip load variation, tool-work displacements, cutting forces, and workpiece surface error generated by both constant and variable speed machining. By investigating the effects of regeneration and forced vibration during variable speed machining on the vibration of tool-work systems having different cutter diameter-to-workpiece width ratios, it has been shown that variable speed machining is also robust with respect to the geometry of the tool-work system. This work concludes that variable speed machining is safer to use than constant speed machining when the effects of the tool-work dynamics and geometry on the vibration of the cutting process are hard to determine.

scholarly journals Modelling for Contact Stress Control in Automated Polishing

2021 ◽  
Author(s):  
Avery Roswell
Keyword(s):  
Dynamic Model ◽  
Contact Stress ◽  
Tool Path ◽  
Coupling Effect ◽  
Open Loop ◽  
Friction Torque ◽  
Spindle Speed ◽  
Work Piece ◽  
Loop Control ◽  
System A

This research pertains to the initial steps in designing an end-effector for automated polishing, and focuses on: (1) controlling the contact stress on the work-piece surface, and (2) controlling the torque or the spindle speed to overcome the friction torque (hence, preventing the tool from stalling) and maintain a desired polishing rate. By forming a contact stress model, parameter planning is achieved and then augmented to already existing tool path data. A dynamic model for the particular end-of-arm tooling used is derived. The dynamic model clearly shows a coupling effect between the pressure and spindle speed of the system. A closed-loop control scheme, designed to eliminate the coupling is then introduced. The effectiveness of parameter planning is assessed through open loop testing. The parameter planning method allows polishing without significantly changing the part profile, whereas, without the parameter planning, the part profile is changed considerably.

The Trial Research on Suppressing the Chatter by Variable Speed Milling

2011 ◽  
Vol 291-294 ◽  
pp. 2010-2013 ◽  
Author(s):  
Zhi Jian Gou
Keyword(s):  
Cutting Tool ◽  
Face Milling ◽  
Spindle Speed ◽  
Cutting Process ◽  
Variable Speed ◽  
Trajectory Parameter ◽  
Speed Variation ◽  
Cutting Chatter ◽  
Speed Parameter ◽  
Tool Cutting

The vibration occurring in cutting process is a very harmful phenomenon, which destroys the surface finish and dimensional integrity of workpieces and quickens the wear of cutting tool. Cutting chatter can be suppressed or reduced by applying the method of suppressing chatter by variable speed cutting. In order to investigate the effect of variable speed parameters and cutting conditions on suppressing the chatter in face milling, the tests have been conducted.The results have shown that cutting with variable spindle speed cutting in face milling will suppress the development of chatter. If chatter occurs in cutting process, the vibration amplitude of variable speed cutting can reduce by 3-6 times lower than that of constant speed cutting, as long as the variable speed parameter are selected suitably.The values of speed variation amplitude Δn/no and speed variation frequency fn of spindle speed trajectory parameter have great effect on suppressing chatter, Δn/no = 15- 20% and fn = 0.4 - 0.5Hz are suitable.

Experimental Study of Micro Milling Burr Control Based on Process Parameters Optimization

2014 ◽  
Vol 551 ◽  
pp. 569-573 ◽  
Author(s):  
Shu Feng Sun ◽  
An Chen Yin ◽  
Ping Ping Wang ◽  
Qin Dong Zhang
Keyword(s):  
Surface Quality ◽  
Process Parameters ◽  
Feed Rate ◽  
Spindle Speed ◽  
Parameters Optimization ◽  
Test Method ◽  
Cutting Process ◽  
Micro Milling ◽  
Depth Of Cut ◽  
Machining Accuracy

With the development of the times, micro and small products are needed increasingly. The machining accuracy and surface quality are especially important to micro machining. However, in the micro milling, the size of the burr compared with that of the part is much greater than that of conventional milling. Moreover, it is difficult to remove micro milling burr by conventional deburring methods due to the small part size. The existence of burr will not only affect the match of parts, but also reduce the dimensional accuracy and surface quality of the work piece. Therefore, it is important to control and reduce micro-milling burr. Micro-milling experiments are carried out on the material of copper with micro-milling cutter diameter 0.5 mm. Micro grooves are milled with different cutting process parameters. The burrs generated under different conditions are analyzed using orthogonal test method. When the spindle speed and feed rate are constant, burrs increase with the increasing of cutting depth. Keeping the spindle speed and the depth of cut constant, burrs are generated increasingly with the increase of feed rate. And the decreasing of the spindle speed leads to the increase of burrs if the other parameters are constant. The experimental research provides reference for the burr control of micro-milling based on the optimization cutting process parameters.

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