A New Approach of Formulating the Transfer Function for Dynamic Cutting Processes

1989 ◽  
Vol 111 (1) ◽  
pp. 37-47 ◽  
Author(s):  
D. W. Wu
Keyword(s):  
Transfer Function ◽  
Deformation Zone ◽  
Chip Thickness ◽  
Cutting Process ◽  
Elastic Behavior ◽  
Plastic State ◽  
Dynamic Force ◽  
Machining System ◽  
Force Components ◽  
Cutting Processes

The dynamics of a cutting process are very complex in nature. It involves not only the changes of plastic state in the intensive deformation zone but also the elastic behavior of work material surrounding the deformation zone, especially in the vicinity of the tool nose region. These changes are induced by the inner and outer modulations of the uncut chip thickness during the process and at the same time govern the variation of the cutting force. Based on these causal relationships, the transfer function between the vibration variables and the dynamic force components for a single degree-of-freedom machining system has been developed. The characterization of the mechanics of the cutting process by the new model provides more insight into the physics of the cutting dynamics. The model has been tested through computer simulation for both orthogonal wave-generating and wave-removing processes. By reference to existing experimental evidence, the theoretical predictions show a very good agreement with the test results.

Cutting Dynamics in Machine Tool Chatter: Contribution to Machine-Tool Chatter Research—3

1965 ◽  
Vol 87 (4) ◽  
pp. 464-470 ◽  
Author(s):  
R. L. Kegg
Keyword(s):  
Machine Tool ◽  
Metal Cutting ◽  
Chip Thickness ◽  
Cutting Process ◽  
Dynamic Force ◽  
General Technique ◽  
Cross Sensitivity ◽  
Machine Tool Chatter ◽  
Measuring Techniques ◽  
Tool Chatter

This is one of four papers presented simultaneously on the general subject of chatter. This work is concerned with finding a representation of the dynamic metal-cutting process which is suitable for use in a linear closed-loop theory of stability of the system composed of the machine tool structure, the cutting process, and their means of combining. Measuring techniques for experimentally determining this behavior are discussed and some problems in the dynamic measurement of forces are explored. It is found that it is not at all sufficient to simply build a dynamometer whose lowest natural frequency is well beyond the range of interest. It is also shown that dynamic cross sensitivity can far exceed static cross sensitivity so that a more general technique for data correction developed in the present work must be used to calibrate dynamic force data. Results obtained to date with an oscillating tool and a flat uncut surface show that some phase, increasing with frequency, is always present between the dynamic cutting forces and the oscillatory uncut chip thickness. This phase is different for the two components of the resultant cutting force. It is felt that two mechanisms, both associated with the tool clearance flank, can explain most of the dynamic cutting effects found in testing.

Experimental Investigations in Cutting Dynamics

1993 ◽  
Vol 115 (4) ◽  
pp. 508-511 ◽  
Author(s):  
K. Marchelek ◽  
J. Tomko´w
Keyword(s):  
Transfer Functions ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Cutting Process ◽  
Experimental Investigations ◽  
Process Dynamics ◽  
Cutting Force Components ◽  
Force Components ◽  
Additive Influence ◽  
Process Transfer

This paper presents the results of an investigation of cutting process transfer functions in orthogonal cutting. An empirical model of cutting process dynamics with respect to the inner modulation of the chip thickness has been developed. The hypothesis about the independent and additive influence of both inner and outer modulation on the cutting force components has been confirmed.

Rectification of Piezoelectric Dynamometer Force Signals During Low Frequency Vibration Assisted Drilling

2013 ◽  
Author(s):  
A. Sadek ◽  
M. Meshreki ◽  
M. H. Attia
Keyword(s):  
Transfer Function ◽  
Degrees Of Freedom ◽  
Research Work ◽  
Low Frequency ◽  
High Amplitude ◽  
Force Transducer ◽  
Dynamic Force ◽  
Low Frequency Vibration ◽  
Measured Force ◽  
Force Components

In vibration assisted drilling (VAD), a controlled harmonic motion is superimposed over the principal drilling feed motion in order to create an intermittent cutting state, which reduces cutting forces and temperatures, facilitates chip removal, and increases the possibility for dry machining. However, accurate force measurements during VAD operations has been a challenge especially in systems, where the force transducer is part of the vibrating mass mounted on the shaker head, due to the dynamic force errors. Conventional signal filtering and compensation techniques were found to be not applicable for attenuating undesirable VAD dynamic force components, which exist in the measured force signals at the same frequency of superimposed modulation. This research work presents a corrective dynamic model that rectifies the erroneous VAD tangential and axial force signals measured by a commercial piezoelectric dynamometer mounted on electro-magnetic shakers for the low frequency/high amplitude (LF/HA) regime. An experimental modal analysis in tangential and axial directions was conducted in order to define the transfer function of a multiple degrees of freedom VAD system mounted on a vibrating base (shaker). The rectified force is then obtained by plugging the relative motion between the dynamometer base and face measured during cutting into the system transfer function. The predicted rectified force components showed very high conformance with known impact and sinusoidal excitation forces used for validation. Moreover, the developed corrective model was capable of predicting some features in the VAD force signals that were not fully captured in the measured force signals during cutting.

Identification of Cutter Axis Tilt in End Milling

1997 ◽  
Vol 119 (2) ◽  
pp. 178-185 ◽  
Author(s):  
Li Zheng ◽  
S. Y. Liang
Keyword(s):  
Cutting Force ◽  
Cutting Forces ◽  
End Milling ◽  
Chip Thickness ◽  
Cutting Parameters ◽  
Milling Process ◽  
Mathematical Representation ◽  
Thickness Variation ◽  
Dynamic Force ◽  
Force Components

The scope of the paper is to discuss the identification of cutter axis tilt in end milling process via cutting force analysis. Cutter axis tilt redistributes the chip load among flutes thereby generating minor frequency components of cutting forces. These minor components can be utilized to infer the tilt geometry during the cutting action. This study involved the mathematical representation of chip thickness variation due to tilt, the modeling of local forces in relation to instantaneous chip thickness, the formulation of total cutting forces through convolution integration in the angle domain, the derivation of dynamic force components in the frequency domain, and the solution for tilt geometry from the dynamic cutting forces. Results show that the tilt magnitude and orientation can be estimated given the dynamic cutting force components along with the tool/work geometry, cutting parameters, and machining configuration. Numerical simulation results confirmed the validity of the angle domain convolution approach, and the end milling experimental data agreed with the analytical model.

Research of machining forces and technological features of cast PA6, POM C and UHMW-PE HD 1000

2010 ◽  
Vol 1 (1) ◽  
pp. 136-143
Author(s):  
Robert Keresztes ◽  
Gabor Kalacska
Keyword(s):  
Injection Molding ◽  
Cutting Force ◽  
Mechanical Engineering ◽  
Cutting Process ◽  
Engineering Practice ◽  
Serial Production ◽  
Machining Forces ◽  
Engineering Plastics ◽  
Machine Elements ◽  
Cutting Processes

Nowadays parts made of up-to-date engineering plastics are used more and morein mechanical engineering practice. These machine-elements are produced most frequentlyby injection molding or by one cutting process. The injection molding technology are usedgenerally for great number of pieces, in case of serial production while cutting processes arepreferred to piece (unit) or smaller number production.We used lathe and measured the main- and feeding-directional cutting force at differentengineering polymers (cast PA6, POM C and UHMW PE HD 1000). The analysis made canbe well used in practice.

scholarly journals Simulating the effect of depth of cut and feed rate on the force components in face milling

2019 ◽  
Vol 9 (1) ◽  
pp. 65-72
Author(s):  
Mohammad Zaher Akkad ◽  
Felhő Csaba
Keyword(s):  
Feed Rate ◽  
Face Milling ◽  
Depth Of Cut ◽  
Third Wave ◽  
Cutting Depth ◽  
Milling Operation ◽  
The Face ◽  
Force Components ◽  
Cutting Processes ◽  
The Impact

This paper presents a study about the workpiece force components (Fx, Fy, Fz) changes in face milling, which results from changing the depth of cut and the feed rate values. The values of the three force components in the face milling operation were found through the FEA-software AdvantEdge by Third Wave Systems. This program is uniquely intended for modelling of cutting processes. Simulations were carried out within five different cutting depth of cut and feed rate, to compare the obtained values and find out the results of the impact of changes on the three force components.

scholarly journals Residual Stresses Distribution Posterior to Welding and Cutting Processes

2021 ◽  
Author(s):  
Asma Manai
Keyword(s):  
Fatigue Life ◽  
Residual Stresses ◽  
Weld Seam ◽  
Considerable Change ◽  
Cutting Process ◽  
Local Material ◽  
Weld Residual Stress ◽  
Exact Size ◽  
Cutting Processes ◽  
Welding Processes

Welding is a joining process that leads to considerable change in the local material and the formation of welding residual stresses (RS). Welding residual stresses can be compressive (beneficial for the fatigue life) or tensile (harmful for the fatigue life). In this chapter, a probabilistic analysis of residual stresses distribution posterior to welding processes is carried out. Several researchers stated that the type of the introduced stresses either compressive or tensile depends on several factors. Some of these factors are listed in this chapter. Welding of mega-structures is carried out in the workshops, then a cutting process takes place to construct the exact size of the structural components. This cutting process has a significant effect on the weld residual stresses re-distribution. A study of the re-distribution of the weld residual stress after cutting was performed. It was found that independent of the weld seam length, the residual stresses re-distributed up to 60 % of the weld seam length.

Effect of Large Cross-Section Oxygen-Propane Flame Cutting on Microstructure in Heat-Affected Zone

2013 ◽  
Vol 274 ◽  
pp. 249-252
Author(s):  
Zhi Xin Wang ◽  
Yong Kui Han ◽  
Yong Qiu Chen
Keyword(s):  
Cross Section ◽  
Heat Affected Zone ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Pressure Vessels ◽  
Manufacturing Industries ◽  
Cutting Process ◽  
Pure Oxygen ◽  
Cutting Processes ◽  
34Crnimo6 Steel

Many metal-manufacturing industries include oxyfuel gas cutting among their manufacturing processes because cutting was often used in metal-cutting processes, specifically in the large castings and forgings and the fabrication of pressure vessels. The oxyfuel gas cutting process uses controlled chemical reactions to remove preheated metal by rapid oxidation in a stream of pure oxygen. Previous research has demonstrated microstructure in heat-affected zone varied depending on the gas used for the combustion as well as the cutting speed (Vc) used during the process. In this research, 34CrNiMo6 steel of 900 mm in thickness and 45 carbon steel of 450 mm in thickness were cut using an oxygen-propane flame cutting process. Then, macroscopic morphology and microstructure test were done to analyze the influence of the thickness of cutting cross-section. The results showed, in general, the width of heat-affected zone increased with the thickness of cutting cross-section. Also, it was demonstrated that heat-affected zone in the bottom and top section was wider than others.

A comprehensive experiment-based approach to generate stress field and slip lines in cutting process

2021 ◽  
pp. 1-18
Author(s):  
Zheng-Yan Yang ◽  
Xiao-Ming Zhang ◽  
Guang-Chao Nie ◽  
Dong Zhang ◽  
Han Ding
Keyword(s):  
Stress Field ◽  
Deformation Zone ◽  
Metal Cutting ◽  
Transfer Problem ◽  
Maximum Shear Stress ◽  
Cutting Temperature ◽  
Cutting Process ◽  
Slip Lines ◽  
Strain And Strain Rate ◽  
Main Deformation

Abstract This study proposes a comprehensive experiment-based method to determine stress field and slip lines in metal cutting process. The chip geometry and workpiece's strain and strain rate fields are determined using an in-situ imaging technique. The two-dimensional (2D) heat transfer problem for the steady-state cutting process is solved to derive the cutting temperature, and the flow stresses of work material in the main deformation zone are calculated based on the plasticity theory. Furthermore, the stress field is comprehensively determined to satisfy the stress equilibrium, friction law along the tool-chip interface, and traction-free boundary condition along the uncut chip surface. In addition, slip lines in the main deformation zone are derived according to the direction of maximum shear stress without the assumption of perfect rigid-plastic material. The proposed method is validated by comparing the cutting forces calculated based on the obtained stress field with the experimentally measurements.

scholarly journals Identification of factors influencing insertion characteristics of cochlear implant electrode carriers

2019 ◽  
Vol 5 (1) ◽  
pp. 441-443
Author(s):  
Silke Hügl ◽  
Nina Aldag ◽  
Thomas Lenarz ◽  
Thomas S. Rau ◽  
Alexander Becker ◽  
...  
Keyword(s):  
Cochlear Implant ◽  
Test Bench ◽  
Time Interval ◽  
Dynamic Force ◽  
Friction Forces ◽  
Factors Influencing ◽  
Constant Diameter ◽  
Constant Radius ◽  
Force Components ◽  
Insertion Process

AbstractInsertion studies in artificial cochlea models (aCM) are used for the analysis of insertion characteristics of different cochlear implant electrode carrier (EC) designs by measuring insertion forces. These forces are summed forces due to the measuring position which is directly underneath the aCM. The current hypothesis is that they include dynamic friction forces during the insertion process and the forces needed to bend an initially straight EC into the curved form of the aCM. For the purposes of the present study, straight EC substitutes with a constant diameter of 0.7 mm and 20.5 mm intracochlear length were fabricated out of silicone in two versions with different stiffness by varying the number of embedded wires. The EC substitutes were inserted into three different models made of polytetrafluoroethylene (PTFE), each model showing only one constant radius. Three different insertion speeds were used (0.11 / 0.4 / 1.6 mm/s) with an automated insertion test bench. For each parameter combination (curvature, speed, stiffness) twelve insertions were conducted. Measurements included six full insertions and six paused insertions. Paused insertions include a ten second paused time interval without further insertion movement each five millimetres. Measurements showed that dynamic and static components of the measured summed forces can be identified. Dynamic force components increase with increased insertion speeds and also with increased stiffness of the EC substitutes. Both force components decrease with larger radius of the PTFE model. After the insertion, the EC substitutes showed a curved shape, which indicates a plastic deformation of the embedded wires due to the insertion into the curved models. The results can be used for further research on an analytical model to predict the insertions forces of a specific combination of selected parameters as insertion speed and type of EC, combined with given factors such as cochlear geometry.

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