Model Of Cutting Process Research Articles

Kirchhoff's law-based velocity-controlled motion models to predict real-time cutting forces in minimally invasive surgeries

A theoretical framework, united by a “system effect” is formulated to model the cutting/haptic force evolution at the cutting edge of a surgical cutting instrument during its penetration into soft biological tissue in minimally invasive surgery. Other cutting process responses, including tissue fracture force, friction force, and damping, are predicted by the model as well. The model is based on a velocity-controlled formulation of the corresponding equations of motion, derived for a surgical cutting instrument and tissue based on Kirchhoff's fundamental energy conservation law. It provides nearly zero residues (absolute errors) in the equations of motion balances. In addition, concurrent closing relationships for the fracture force, friction coefficient, friction force, process damping, strain rate function (a constitutive tissue model), and their implementation within the proposed theoretical framework are established. The advantage of the method is its ability to make precise real-time predictions of the aperiodic fluctuating evolutions of the cutting forces and the other process responses. It allows for the robust modeling of the interactions between a medical instrument and a nonlinear viscoelastic tissue under any physically feasible working conditions. The cutting process model was partially qualitatively verified through numerical simulations and by comparing the computed cutting forces with experimentally measured values during robotic uniaxial biopsy needle constant velocity insertion into artificial gel tissue, obtained from previous experimental research. The comparison has shown a qualitatively similar adequate trend in the evolution of the experimentally measured and numerically predicted cutting forces during insertion of the needle.

Investigation of intermittent cutting mechanism of abrasive particles in ultrasonic-assisted external cylindrical honing

Ultrasonic-assisted honing, which is a finishing grinding method, has been considered effective for improving the cutting performance of abrasive particles. However, the effect mechanism of the ultrasonic vibration on the cutting process of abrasive particles has not yet been clarified, which hinders the application and development of this technology. In this study, new kinematics and cutting process models of a single abrasive particle in ultrasonic-assisted external cylindrical honing (UAECH) were established. The parameters and interruption conditions affecting the intermittent cutting process of the abrasive particle were clarified based on the coupling effect of ultrasonic vibration and rotation of workpiece. Finite element simulation analysis has revealed that the increases in ultrasonic frequency and amplitude can reduce the interruption threshold and cutting time proportion in the intermittent cutting process of abrasive particles mainly by increasing the relative velocity of abrasive particles. Furthermore, for the cutting depth and rotation speed, their influence on the intermittent cutting process is mainly based on the change of the deformation rate of workpiece material. Moreover, it was found that there was counteraction effect between the tangential forces on the symmetrical surfaces of the abrasive particle in UAECH, which can help reduce the tangential honing force and improve the honing performance. The experimental results demonstrated a significant improvement in the average tangential honing force in UAECH and novel dents surface topography, which can provide guidance for the application of ultrasonic vibration in the grinding field and development of forming processes for functional surface topography in honing.

Cutting Process Model Design of Cutter Suction Dredger Based on Auto Regressive eXogenous and Radial Basis Function model

The dredging operation of the strander dredger is complex, and the mathematical model established according to its key equipment characteristics is not possible to describe such a system having time degeneration and non-linear. Therefore, based on the analysis of mud formation process of dredger, RBF-ARX model is used to model the cutting process, and mud concentration is taken as the output. This modeling method is a combination model based on the theory of Auto-Regressive eXogenous (ARX) model and Gauss radial basis function (Radial Basis Function) neural network (RBF). The comparison between the simulation results and the actual data shows that the model can accurately describe the dynamic characteristics of cutter suction dredger in the cutting process.

Heat Modeling and Experiment of Micro-drilling with Multi-parameter Influence

Cutting temperature is essential to improve machining technology in micro drilling of hard material. As the unreasonable temperature distribution will increase the complexity of tool-workpiece surface contact, affect the machining quality of tool and the surface integrity of hole wall. In this paper, the cutting process model is combined with the analytical temperature rise model based on time to study the change rule of surface contact conditions. The 40Cr sample was used to carry out drilling experiments. The results show that the high feed micro drill tool is prone to structural differences at high temperature, large area size effect. It makes the contact conditions change significantly, and the heat distribution of system changes, which affects the stability of cutting.

Prediction of laser drilled hole geometries from linear cutting operation by way of artificial neural networks

This paper deals on artificial intelligence (AI) application for the estimation of kerf geometry and hole diameters for laser micro-cutting and laser micro-drilling operations. To this aim laser cutting and laser drilling operation were performed on NIMONIC 263 superalloy sheet, 0.38 mm in nominal thickness, by way of a 100 W fibre laser in modulated wave regime. Linear cuts and holes (by trepanning) were performed fixing the average power at 80 W and changing the pulse duration, the cutting speed, the focus depth and the laser path (the latter only for the drilling operations). Kerf width and the holed diameter, at the upper and downsides, were measured by digital microscopy. Different artificial neural networks (ANNs) were developed and tested to predict the kerf widths and the diameters (at the upper and downside). Two ANNs were addressed to the linear cutting process modelling; also, two further ANNs were developed for micro-drilling on the base of the linear cutting process features. The networks were trained with a subset of data containing the process conditions and the kerf/hole geometry. The ANN test was performed with the remaining data. The results show that ANNs can model the cut and hole geometry as a function of the process parameters. Moreover, the ANN trained with kerf geometry is more efficient. Therefore, a functional correlation between the kerf geometries achievable in the linear cutting process and micro-drilling was assessed.

Analysis of the remote laser cutting process induced damage in carbon fibre reinforced polymers with cutting process simulations

AbstractRemote laser cutting in carbon fibre reinforced polymers is a promising machining technology, which can reduce the main drawback in laser cutting, the heat affected zone. As the heat affected zone has a strong influence on the mechanical behaviour of the composite, an exact characterisation is a key challenge for the simulation and design of fibre reinforced polymers. In order to reach this goal, a laser cutting process model is introduced. Based on the finite difference method, the heat transport is modelled on a macroscopic scale. The macroscopic material parameters are calculated with a rule of mixture. Matrix and fibre evaporation, which cause the formation of the matrix evaporation zone and the gap, are modelled with phase transitions and an adaption in the rule of mixture.The simulation results are validated with micro‐sections of the cutting gap.

Unified approach to developing analytical models of different grinding processes based on basic cutting process model

The appearance of modern CNC grinding machines allowed concentrating multipass and multistage processing of different workpiece surfaces by means of using different grinding types and different tool types. Meanwhile, the processing of different surfaces is carried out with different allowances and accuracy requirements and performed according to the specified stepwise cycles of the feeds control. As a result, there is a difficult task of quick and reliable calculation of the optimal feed cycles and other cutting modes for different types of processing of different surfaces with various grinding conditions. The solution to this problem is developing of mathematical models that link processing accuracy with cutting modes and other technological conditions of the processing. The development of such models should begin with the creation of a complex of the cutting forces` models for each grinding type. This article describes a method for deriving generalized analytical model of the cutting force for the different grinding types which is based on the functional interrelation between the intensity of the metal removal performed by the wheel and elementary volumes of metal deformable in the shear zone. The complex of the cutting forces models for different grinding types, obtained by means of using this technique, establishes functional interrelation of the cutting force with cutting modes, strength properties of the treated material, kinematics of the grinding process, geometry of the cutting zone, characteristics and geometric parameters of the grinding wheel, etc. It should also be noted that the developed models cover the majority of production conditions and they are wide-range in terms of the main technological parameters (dimensions of the treated surfaces, allowances, tolerance grades, etc.).

Surface texture formation mechanism based on the ultrasonic vibration-assisted grinding process

It is widely accepted that surface textures can significantly improve the tribological properties of surfaces. The purpose of this research was to study surface texture formation mechanism through the ultrasonic vibration-assisted grinding process. First, a single grain cutting process model was established, and the cutting trajectory length and shape were calculated. Second, the single grain profile models were established that considered the dressing effect. Then, by considering continuous cutting process of large amounts of grains, the surface texture formation mechanism model was established. The calculation results were verified by experiments. Finally, the characteristic parameters that described the surface texture topography were proposed and the influence law of the process parameters was analyzed. The results of this research showed that the established theoretical model could accurately describe the ultrasonic vibration-assisted grinding process and the topographical characteristics of the surface texture. By controlling the process parameters, surface textures with controllable topography could be processed. This work can provide a substantially theoretical basis for processing surface textures efficiently.

Structural vibration control using delayed state feedback via LMI approach: with application to chatter stability problems

This paper considers the problem of active vibration control in machining processes to prevent dynamic instability and chatter. A method for robust delayed-state feedback control is presented based on Lyapunov–Krasovskii functionals (LKFs). For fast computation and realizability, a partial state feedback approach based on a reduced order model of structural vibration is considered that matches available sensors and captures the main vibratory modes that impact on stability limits. Robustness to neglected dynamics and other model errors are accounted for by a frequency domain description of model uncertainty, augmented with the basic LKF stability condition. The controller synthesis problem is formulated as a set of linear matrix inequality equations that can be solved numerically using convex optimization methods. Evaluations on a hardware-in-the-loop flexible structure test-bed show that feedback controllers optimized via the LKF stability condition provide significant improvements in stability regions compared with optimized PD control and quadratic regulation. The results confirm the methodology as a useful approach for robust chatter control based on combined flexible structure and cutting process models.

Computationally intelligent modelling of the plasma cutting process

ABSTRACTThis paper investigates the applicability of two computational intelligence methods for the plasma cutting process modelling: artificial neural networks and adaptive neuro-fuzzy inference systems. After exploring the possibilities of neural networks learning from the experimental data for the prediction of the plasma cutting parameter, the adaptive neuro-fuzzy inference system approach was used in order to compare the prediction properties of neural networks and adaptive neuro-fuzzy models. These two methods resulted in the kerf width prediction models for different combinations of input process parameters: cutting current, cutting speed and material thickness, whose significance was assessed by multi-criteria analysis. Descriptive statistics and a visual exploration of two sets of neural-network and adaptive neuro-fuzzy modelled data showed good agreement with the experimental results and their trends. This was additionally confirmed by the t-test and Analysis of Variance, which also provided the selection of the most favourable method for plasma cutting modelling. Accordingly, the adaptive neuro-fuzzy inference systems showed superior modelling capabilities over artificial neural networks for this particular problem setting.

An application of non-ordinary state-based peridynamics theory in cutting process modelling of unidirectional carbon fiber reinforced polymer material

The usage of carbon-fiber-reinforced polymer (CFRP) composite keeps increasing in modern industries. However, because of the complexity of CFRP structure, the analysis for CFRP failure process, especially for machining process, is quite difficult. This paper presents a non-ordinary state-based peridynamic approach that can be applied to CFRP machining analysis. In order to describe the composite’s anisotropy, fiber bond and matrix bond is first introduced in this approach. For describing the failure characteristic of composite, the Maximum stress failure criteria and Hashin failure criteria is then incorporated into the state-based peridynamic approach. Finally, the contact state between tool and workpiece is detected by utilizing the penalty method in modeling the machining process. To demonstrate the effectiveness of the present method, tension and cutting experiments are conducted as well.

The temperature process analysis and control on laser-assisted milling of nickel-based superalloy

Nickel-based alloys of Inconel 718 are well-known for their excellent properties of high-temperature hardness, mechanical strength, and wear resistance and are currently popular and applied in aerospace industry, such as the manufacturing of aero-engine turbine disks and compressor disk. Laser-assisted milling (LAML), which uses laser to locally heat the workpiece to improve the machinability of the material, has the advantage of increasing machining efficiency, reducing tool wear, and improving machining quality. In LAML, laser preheating temperature is the most important parameter influencing laser heating effect; however, constant laser energy commonly used in experiments cannot provide a stable preheating temperature. Therefore, temperature feedback control method is used in LAML and composite simulation models are established to simulate the temperature field and cutting process. The composite simulation models contain laser preheating temperature model, temperature feedback model, temperature difference prediction model, and cutting process model. Finite element method and neural network calculation method are used in building the model, which can be used to get the temperature difference, and then through monitoring to control the temperature of the laser heating. The simulation results show that the laser energy and the laser moving speed are the main factors affecting the laser preheating temperature, the difference between cutting area temperature and monitor temperature. A LAML experiment system is set up; cutting force and cutting chips are obtained through experiments. The simulation results express a good agreement with the experimental results, thus demonstrating the feasibility of the temperature-monitoring laser heating system and capabilities of LAML in fabricating difficult-to-machine parts for industrial implementation.

Optimisation Of Cutting Parameters Of Composite Material Laser Cutting Process By Taguchi Method

The aim of this work is to develop a laser cutting process model that can predict the relationship between the process input parameters and resultant surface roughness, kerf width characteristics. The research conduct is based on the Design of Experiment (DOE) analysis. Response Surface Methodology (RSM) is used in this work. It is one of the most practical and most effective techniques to develop a process model. Even though RSM has been used for the optimization of the laser process, this research investigates laser cutting of materials like Composite wood (veneer)to be best circumstances of laser cutting using RSM process. The input parameters evaluated are focal length, power supply and cutting speed, the output responses being kerf width, surface roughness, temperature. To efficiently optimize and customize the kerf width and surface roughness characteristics, a machine laser cutting process model using Taguchi L9 orthogonal methodology was proposed.

Hybrid Digital Image Correlation–Finite Element Modeling Approach for Modeling of Orthogonal Cutting Process

Cutting process modeling is still a significant challenge due to the severe plastic deformation of the workpiece and intense friction between the workpiece and tool. Nowadays, a novel experimental approach based on digital image correlation (DIC) technique has been utilized to study the severe deformation of the workpiece. However, the experimentally measured velocity field does not necessarily satisfy the equilibrium equation that is one of the fundamental governing equations in solid mechanics due to the measurement errors; hence, accurate stress fields could hardly be derived. In this paper, we propose a hybrid DIC-FEM approach to optimize the velocity field and generate a stress field that is in an equilibrium state. First, the analysis region for finite element modeling (FEM) is selected according to the captured image, and the DIC results are used to track the deformation history of the material points. Secondly, the deviatoric stresses of the analysis region are calculated by employing the plastic theory. Thirdly, the hydrostatic pressures are acquired through solving over-constrained equations derived through FEM. Finally, the velocity field is optimized to satisfy the equilibrium equation and the boundary conditions (BCs) with the DIC results serving as an initial value of the workpiece velocity field. To validate this approach, the deformations including the velocity and strain yielded by the hybrid method are compared with the DIC results. The stress fields are presented to demonstrate the satisfaction of the equilibrium equation and the BCs. Moreover, cutting forces calculated through the integration of the stress tensors are compared against the FEM simulations and the experimental measurement.

Development of the Internally Cutting Milling Cutter Model with Radial Advance for Treatment of Profiling Rolls

Demountable joints for torque transmission are some of the most important of the machine elements. High requirements on fatigue value, life time, etc. are made for them. In this paper we discuss the method of profiling rolls treatment with the application of the internally cutting milling cutter with radial advance. We have solved the task of modeling for the front and back surfaces of the cutter knives with the aid of the surface shaping geometrical theory. On the basis of the developed models it is possible to develop the cutting process model and calculate the evaluative parameters. This may lead to increasing of effectiveness of the design process for this cutters type.

Improved Forecasting Compensatory Control through Kalman Filtering

The deformation of large thin-walled parts during the cutting processing will decrease the part accuracy, and on-line error forecasting and compensation control is usually used. The forecasting compensatory control (FCC) depending on modelling technique is usually helpful for some regular deformation. Random deformation of weak rigid thin-walled parts in the cutting process cannot be compensated easily. This paper develops an improved forecasting compensatory control method based on Kalman filtering algorithm to improve the prediction accuracy. The Kalman filtering algorithm produces the estimation of the real deformation based on the measured deformation data, and the statistical noise in measuring and cutting process modeling can be reduced. The effectiveness of the proposed method is validated with simulation examples.

An integrated prediction model including the cutting process for virtual product development of machine tools

Recently activities for shortening the development time of machine tools and demands for high-value products are consistently being increased. As a result, many studies for predicting the performance in design stage have been conducted to solve these issues. So far, most manufacturers of machine tools have verified designs excluding the cutting process, even though the main performance is the machining quality of the workpiece. Therefore, it has been required to consider together the cutting process model for analyzing the machining quality before the manufacturing of the prototype. This paper presents an integrated dynamic model considering the all interaction of the machine structure, the control system, and the cutting process. The modal truncation technique using the steady-state dynamic analysis in a selected location and frequency range of interest is applied to increase the efficiency of mechatronics simulations including the cutting process. In particular, this proposed prediction model allows accurate design verifications for high-speed machines because it reflects the influences of the high inertia forces and the contour errors caused by high feed rate. Several peripheral milling applications were demonstrated in order to show the feasibility of the proposed prediction model, and we confirmed the superiority of prediction by comparing the simulated and measured results in high feed milling.

Principles of Cutting Process Modelling and New Algorithm Proposal

Nowadays the pressure to increase the efficiency of the machining processes is constantly growing. The efficiency of the machining process can be pursued from two basic perspectives - enhancing the cost-effectiveness of the process (decreasing production costs) or increasing production in time. Via these approaches alone, manufacturers of parts as well as suppliers of machine tools and cutting tools try to improve their position in a highly competitive market. One of the approaches to increase efficiency is the correct choice and subsequent optimal exploitation of the potential of cutting tools and machine tools as well as a reduction in the energy intensity of the cutting processes for a given component. That is what led to the idea of creating an analytical-material model for determining the force interaction between the cutting tool and workpiece, energy intensity and machining process efficiency. The result will be an application that helps technologists in practice to choose correctly the appropriate types of cutting tools, operations, machine tools and also quickly determine the main parameters of the cutting process so that there is the possibility of comparing their results with other variants. The first step and goal is to create an overview of the cutting processes and the associated cutting process modelling, compare their advantages and disadvantages, and then propose an approach of our own.

Optimizing CNC wood milling operations with the use of genetic algorithms on CAM software

Main focus of this paper is to introduce an appropriate methodology and create a Genetic Algorithm that optimizes wood milling operations, since wood is one of the primary materials used in both structures and musical instruments building. Mechanical properties of wood were considered in the cutting process modeling on CAM software as far as machining parameter values are concerned. Key machining parameters are explained along with their effect on the final product. The proposed Genetic Algorithm was specifically built for wood milling applications and its operators are examined in detail. The undertaken quality characteristics were minimum machining time and optimal surface quality, thus covering both productivity and quality goals at the same time. As a case study, a novel custom 3D CAD model of an electric guitar body was introduced, on which the proposed optimization methodology was implemented, so as to reveal its efficiency and effectiveness.

A method of using turning process excitation to determine dynamic cutting coefficients

Identification of the dynamic cutting force coefficients is an essential work in cutting process modeling. The excitation equipment employed to produce dynamic cutting process is usually sophisticated and may lead to potential error. An alternative method of turning process excitation is proposed to simplify the procedure of cutting dynamics measurement. A cantilever workpiece used in cylindrical turning process has been modeled with a double degree-of-freedom system that supports variable dynamic parameters. The structural dynamics of the equivalent system are analyzed with the theoretical derivation and the finite element simulations. The influence of structural dynamic variation on the chatter frequency is investigated, based on which the self-excited chatter is considered as a method of the turning process excitation. This method is applied in the cutting dynamics tests. The dynamic cutting force coefficients could be measured through a single chattering turning process. Stability analysis is conducted for verification of the measured dynamic cutting coefficients.