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.

Determination of Inner and Outer Modulation Dynamics in Orthogonal Cutting

1987 ◽  
Vol 109 (4) ◽  
pp. 275-280 ◽  
Author(s):  
T. Y. Ahn ◽  
K. F. Eman ◽  
S. M. Wu
Keyword(s):  
Orthogonal Cutting ◽  
Theoretical Background ◽  
Cutting Process ◽  
Experimental Realization ◽  
Process Dynamics ◽  
Orthogonal Turning ◽  
Machine Tool Structure ◽  
Dynamic Cutting Force ◽  
Experimental Errors ◽  
Modeling Strategy

Many efforts have been devoted in the past to the identification of the dynamic behavior of the cutting process. Nevertheless, there have been no consistent results due to the inherent complexity of the cutting process, and the methodological and experimental errors involved. Among the problems to be solved, the experimental realization of the double modulation is the most difficult one. Present approaches use elaborate instrumentation and assume the delayed inner modulation for the outer modulation. This assumption may not hold under all circumstances and it will be modified in this paper. The present method approaches the cutting process as a one-input one-output process consisting of the inner modulation and dynamic cutting force component. The application of bivariate time series models give the transfer function of the inner modulation dynamics. The outer modulation dynamics’ effect on the cutting process is subsequently determined from the disturbance noise dynamics. The theoretical background for the proposed approach along with a new modeling strategy has been introduced in detail. The experimental verification of the theoretical postulates and the identification of the cutting process dynamics were carried out using actual data collected from an orthogonal turning process of a tubular workpiece. External white noise excitation was used and the experimental setup was designed to minimize the errors caused by inertia and disturbances. Although the proposed method requires prior knowledge of the machine tool structure, it requires a comparatively simple experimental procedure and minimizes the possible errors associated with the signal processing task.

Influence of Reground Tool Sharpness on Micro-Cutting Process

2010 ◽  
Vol 37-38 ◽  
pp. 550-553
Author(s):  
Xin Li Tian ◽  
Zhao Li ◽  
Xiu Jian Tang ◽  
Fang Guo ◽  
Ai Bing Yu
Keyword(s):  
Cutting Forces ◽  
Orthogonal Cutting ◽  
Cutting Tools ◽  
Chip Thickness ◽  
Cutting Edge ◽  
Cutting Process ◽  
Micro Cutting ◽  
Temperature Distributions ◽  
Edge Radius ◽  
1045 Steel

Tool edge radius has obvious influences on micro-cutting process. It considers the ratio of the cutting edge radius and the uncut chip thickness as the relative tool sharpness (RST). FEM simulations of orthogonal cutting processes were studied with dynamics explicit ALE method. AISI 1045 steel was chosen for workpiece, and cemented carbide was chosen for cutting tool. Sixteen cutting edges with different RTS values were chosen for analysis. Cutting forces and temperature distributions were calculated for carbide cutting tools with these RTS values. Cutting edge with a small RTS obtains large cutting forces. Ploughing force tend to sharply increase when the RTS of the cutting edge is small. Cutting edge with a reasonable RTS reduces the heat generation and presents reasonable temperature distributions, which is beneficial to cutting life. The force and temperature distributions demonstrate that there is a reasonable RTS range for the cutting edge.

Machining Forces: Some Effects of Removing a Wavy Surface

1966 ◽  
Vol 8 (2) ◽  
pp. 129-140 ◽  
Author(s):  
P. W. Wallace ◽  
C. Andrew
Keyword(s):  
Chip Thickness ◽  
Shear Plane ◽  
Shear Angle ◽  
Surface Slope ◽  
Experimental Conditions ◽  
Undeformed Chip Thickness ◽  
Cutting Force Components ◽  
The Mean ◽  
Force Components ◽  
Made In

Previous work has shown that during the removal of a surface waveform oscillating cutting force components arise which may have a phase difference with respect to the oscillating component of undeformed chip thickness; it has also shown that the shear angle is affected by the slopes of the surface waveform. However, no attempt to predict the oscillating force behaviour from the geometry of cutting has been reported. The present work attempts to achieve such a prediction by means of an analysis of the phase and magnitude of the oscillating force components acting in two directions; in the directions of the mean shear plane and of the tool rake face. In the analysis it is assumed that the shear angle oscillates in phase with and proportionally to the surface slope, and that the curvature of the chip varies with the undeformed chip thickness. An experimental technique for cutting with variable undeformed chip thickness is described, together with a method for recording and measuring the oscillating components of force and undeformed chip thickness. Experimental results are presented which show the assumptions made in the analysis to be substantially valid; the predicted oscillating forces are shown to be in adequate agreement with experiment over a range of experimental conditions. It is shown that the oscillation of the shear angle is primarily dependent on the surface slope and that the frictional force behaviour is consistent with the characteristics of the two regions of friction, sticking and sliding, as found in work on cutting with constant undeformed chip thickness.

Fundamental Machining Characteristics of Ultrasonic Assisted Turning of Titanium Alloy Ti-6Al-4V

2013 ◽  
Vol 797 ◽  
pp. 344-349 ◽  
Author(s):  
Yong Bo Wu ◽  
Jing Ti Niu ◽  
M. Fujimoto ◽  
Mitsuyoshi Nomura
Keyword(s):  
Titanium Alloy ◽  
Cutting Force ◽  
High Efficiency ◽  
Experimental Investigations ◽  
Work Surface ◽  
Ultrasonic Assisted ◽  
Cutting Force Components ◽  
Level 3 ◽  
Force Components ◽  
Machining Characteristics

In this paper, a new machining method is proposed for the high efficiency turning of titanium alloy Ti-6Al-4V in which the cutting tool is ultrasonically vibrated. An experimental setup is constructed by installing an ultrasonic cutting unit onto a NC lathe followed by experimental investigations on the fundamental machining characteristics. The results obtained in the current work showed that (1) the cutting force decreases with the increase in the power supplying level (i.e., the ultrasonic vibration (UV) amplitude), e.g., the cutting force components in X-. Y-and Z-directions were decreased by 48%, 45% and 87%, respectively, once the UV has been applied to the tool at the power supplying level of 50%; (2) the cutting marks with knit pattern are formed on work-surface with UV while the parallel distributed cutting marks are generated without UV, and the surface roughness is decreased by up to 10% when the UV is applied at an appropriate power supplying level; (3) the work-surface straightness is improved by 46% once the UV is applied.

scholarly journals Cutting Forces Prediction in the Dry Slotting of Aluminium Stacks

2014 ◽  
Vol 797 ◽  
pp. 47-52
Author(s):  
Jorge Salguero ◽  
Madalina Calamaz ◽  
Moisés Batista ◽  
Franck Girot ◽  
Mariano Marcos Bárcena
Keyword(s):  
Cutting Force ◽  
Cutting Forces ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Parametric Models ◽  
Cutting Process ◽  
Cutting Force Components ◽  
Force Components ◽  
Input Variables ◽  
The Individual

Cutting forces are one of the inherent phenomena and a very significant indicator of the metal cutting process. The work presented in this paper is an investigation of the prediction of these parameters in slotting processes of UNS A92024-T3 (Al-Cu) stacks. So, cutting speed (V) and feed per tooth (fz) based parametric models, for experimental components of cutting force, F(fz,V) have been proposed. These models have been developed from the individual models extracted from the marginal adjustment of the cutting force components to each one of the input variables: F(fz) and F(V).

scholarly journals An investigation of force components in orthogonal cutting of medical grade cobalt–chromium alloy (ASTM F1537)

2017 ◽  
Vol 231 (4) ◽  
pp. 269-275 ◽  
Author(s):  
Szymon Baron ◽  
Eamonn Ahearne
Keyword(s):  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Lifestyle Changes ◽  
Ageing Population ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Undeformed Chip Thickness ◽  
Force Components ◽  
Medical Grade

An ageing population, increased physical activity and obesity are identified as lifestyle changes that are contributing to the ongoing growth in the use of in-vivo prosthetics for total hip and knee arthroplasty. Cobalt–chromium–molybdenum (Co-Cr-Mo) alloys, due to their mechanical properties and excellent biocompatibility, qualify as a class of materials that meet the stringent functional requirements of these devices. To cost effectively assure the required dimensional and geometric tolerances, manufacturers rely on high-precision machining. However, a comprehensive literature review has shown that there has been limited research into the fundamental mechanisms in mechanical cutting of these alloys. This article reports on the determination of the basic cutting-force coefficients in orthogonal cutting of medical grade Co-Cr-Mo alloy ASTM F1537 over an extended range of cutting speeds ([Formula: see text]) and levels of undeformed chip thickness ([Formula: see text]). A detailed characterisation of the segmented chip morphology over this range is also reported, allowing for an estimation of the shear plane angle and, overall, providing a basis for macro-mechanic modelling of more complex cutting processes. The results are compared with a baseline medical grade titanium alloy, Ti-6Al-4V ASTM F136, and it is shown that the tangential and thrust-force components generated were, respectively, ≈35% and ≈84% higher, depending primarily on undeformed chip thickness but with some influence of the cutting speed.

Determination of Cutting Forces in Oblique Cutting

2015 ◽  
Vol 756 ◽  
pp. 659-664 ◽  
Author(s):  
A.V. Filippov ◽  
E.O. Filippova
Keyword(s):  
Cutting Force ◽  
Cutting Forces ◽  
Theoretical Calculations ◽  
Experimental Investigations ◽  
Cutting Depth ◽  
Turning Operations ◽  
Error Check ◽  
Cutting Force Components ◽  
Force Components

This study describes the method of determining cutting force components in oblique turning. The scheme of how the investigations were performed is presented. The characteristic curves of cutting force components vs. thickness of the material removed, tool clearance and tool rake angles are shown. The study presents the data, which have been obtained during the experimental investigations and analytically calculated, on how the cutting forces are subject to changes depending on a cutter angle, cutting depth and feed in oblique turning operations. The analysis of approximation of the experimental results and error check of the theoretical calculations relative to the experimental data are given.

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.

scholarly journals Mechanics and Dynamics of Ball End Milling

1998 ◽  
Vol 120 (4) ◽  
pp. 684-692 ◽  
Author(s):  
Y. Altıntas¸ ◽  
P. Lee
Keyword(s):  
Time Domain ◽  
Transfer Functions ◽  
End Milling ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Milling Process ◽  
Body Motion ◽  
Ball End Milling ◽  
Cutting Model ◽  
End Milling Process

Mechanics and dynamics of cutting with helical ball end mills are presented. The helical ball end mill attached to the spindle is modelled by orthogonal structural modes in the feed and normal directions at the tool tip. For a given cutter geometry, the cutting coefficients are transformed from an orthogonal cutting data base using an oblique cutting model. The three dimensional swept surface by the cutter is digitized using the true trochoidal kinematics of ball end milling process in time domain. The dynamically regenerated chip thickness, which consists of rigid body motion of the tooth and structural displacements, is evaluated at discrete time intervals by comparing the present and previous tooth marks left on the finish surface. The process is simulated in time domain by considering the instantaneous regenerative chip load, local cutting force coefficients, structural transfer functions and the geometry of ball end milling process. The proposed model predicts cutting forces, surface finish and chatter stability lobes, and is verified experimentally under both static and dynamic cutting conditions.

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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