Machine Tool Simulation Research Articles

Multi-axis CNC finishing and surface roughness prediction of TC11 titanium alloy open integral micro impeller

The titanium alloy open integral micro impeller has a strong material strength and high removal rate in the field of multi-axis CNC machining. The flow channel is tiny and the blades are thin and highly twisted. It is difficult to control the surface accuracy and prone to overcutting and undercutting. The NX2212 software post-processing module plans two distinct blade finishing process routes and verifies them using virtual machine tool simulation, taking into account the technical challenges of micro impeller machining. Following verification, the tool path machining code is imported into MATLAB for data fitting. The workpiece surface working condition is determined based on the simulation findings, the blade surface roughness value is calculated, and a physical simulation model of blade finishing is created in the finite element analysis software. The outcomes demonstrate how well the “segmented and sub-regional cutting” processing method may raise blade accuracy. The leading and trailing edges of the blade both had surface roughness increases of 4.86% and 4.19%. The surface morphology of the micro impeller is measured using a white light interferometer, and it is CNC machined using two distinct process methods. The findings demonstrate that there is a significant difference between the value calculated by the finite element analysis software and the surface roughness value measured experimentally which together make up less than 5%. An investigation of the impact of cutting parameters on the surface roughness of micro-structure components is carried out using a three factor, three-level BBD experiment that is founded on the second-order response surface method. The findings indicate that the feed per tooth influences surface roughness more significantly than cutting depth and cutting speed for a reasonable range of cutting parameters; Surface roughness will rise with lower or higher cutting speeds; Raising the feed per tooth and the cutting speed simultaneously may reduce surface roughness; Surface roughness can be accurately predicted and controlled using the second-order response surface method.

Research on Digital Manufacturing Technology of Key Components of Artificial Knee Joint

The surface of the artificial knee joint manufactured by 3D printing technology is rough. This study uses advanced multi-axis machining technology to study how to improve the manufacturing accuracy of the artificial knee joint surface, and uses five-axis machining CAM software to analyze the process of three-dimensional model of the artificial knee joint and to compile tool path, create a five-axis special post-processor, convert the tool path point file into the NC program for machine tool processing. In order to ensure the safety and efficiency of the processing procedure, a Mikron HEM-500U machine tool simulation platform was built in the VERICUT simulation system for simulation processing verification, and then the blank prototype obtained by 3D printing was processed in a five-axis machine tool to meet medical clinical use requirements.

Comparison of Sensitivity-Guided and Black-Box Machine Tool Parameter Identification

Dynamic machine tool simulation models can be used for various applications such as process simulations, design optimization, and condition monitoring. However, all these applications require that the model replicates the real system’s behavior as accurately as possible. Next to carefully building the model, the parameterization of the model, that is, determining the parameter values the model is based upon, is the most crucial step. This paper describes the application of both sensitivity-based and black-box parameter identification to a machine tool. It further provides a comparison between these two methods and the method of sequential assembly. It is shown that both methods can increase the mode shape conformity by more than 25% and significantly reduce damping deviations. However, sensitivity-based parameter identification is the most economical method, offering the chance to update a dynamic machine tool model within minutes.

Compact thermo-mechanical models for the fast simulation of machine tools with nonlinear component behavior

Abstract In this contribution, advanced modeling of thermo-mechanical effects in machine tools with nonlinear machine components is investigated using the example of a feed axis. Strategies of model order reduction for this coupled thermo-mechanical model with nonlinear subsystem are presented. Numerical investigations of the performance of the resulting reduced-order model compared to the original one conclude this article.

Design and research of digital twin machine tool simulation and monitoring system

The numerical control machine tool is an important part of manufacturing. The speed and accuracy of the machine tool simulation and the monitoring of machine physical model movement, model collision, and operation health are the most common bottlenecks. The previous studies on these problems are discrete and poor in real time. In this paper, combined with the digital twin (DT) technology, a perception-monitor-feedback system architecture is constructed. Based on the improved Gilbert–Johnson–Keerthi (GJK) distance algorithm, the collision information of tool and machine tool can be better detected during the simulation and monitoring of machine tool movement, and the more real workpiece shape can be displayed. Based on the model synchronous motion driven by the production perception data and its potential information extraction, the tool wear online monitoring is carried out. The tool wear online monitoring is performed based on the production perception data–driven model synchronous movement and extraction of its potential information. Finally, the usability and efficiency of the system are verified by an example of a typical shaft part processed by a numerical control machine tool.

Identification of a Practical Digital Twin for Simulation of Machine Tools

A practical digital twin for machine tools is proposed in this study. The proposed digital twin is capable of time-domain simulation of machine tools and consists of a controller model, machining process model, and machine dynamic model. To predict the quality of the machined surface after the finishing processes, a precise dynamic model is required. The developed dynamic model consists of an interaction force model, vibration model, and friction force model. A linear auto regressive with exogenous inputs (ARX) model is adopted for the interaction and vibration models. Based on a systematic analysis of the disturbance forces of the machine tool, the friction characteristics are extracted to a displacement-dependent friction model and velocity-dependent friction model. A nonlinear Hammerstein model is adopted to identify the friction. Online identification systems based on the recursive least-squares (RLS) method are developed and tested for each model.

Development of a machine tool simulator based on VR

Development of a machine tool simulator based on VR

Study on the Configuration Guideline of Objective function for Acceleration/Deceleration Parameter Optimization using a Machine tool simulator

Optimization studies of feed drive system parameters of machine tools are gaining attention. Majority of the studies use the weighted sum of several evaluation indices regarding machine behavior as the objective function. However, there is no clear guideline for designing those weights, which are currently configured empirically. To address this problem, this study has optimized acceleration/deceleration parameters of a milling table with various weight configurations by using a machine tool simulator. Optimized parameters showed clear relationships between the weights related to the magnitude of acceleration and the positional accuracy. That enables weight configuration design to meet various users’ needs.

Experimental and simulation study on chatter stability region of integral impeller with non-uniform allowance.

In order to accurately improve and predict chatter stability region of machining process, an optimization method of machining process with non-uniform allowance of integral impeller was proposed. The modal parameters of the workpiece process system were obtained using the finite element analysis. Based on the regenerative chatter analysis theory, a limit comparison diagram of the stability with uniform allowance and non-uniform allowance was established. The simulation results showed that the non-uniform allowance natural frequency is about 1.43 times as much as the uniform allowance natural frequency, and the machining system stiffness non-uniform allowance is twice as much as the uniform allowance, while the limit of chatter stability region is increased by 3 times. This article studied uniform allowance and non-uniform allowance of milling chatter stability with experimental method. Tool path for five-axis machining and machine tool simulation based on NX CAM were planned. The comparisons of cutting processing uniform allowance and non-uniform allowance were done, and the surface profile detection of the test part with the three-dimensional scanning was carried out. The experimental results showed that the average optimization rate for manufacturing precision of blade suction surface after optimization and pressure surface was 63.8% and 48.84%. The total experiment showed that this process optimization strategy could effectively improve the stiffness of the integral impeller blade and reduce the cutting chatter of the blade during the cutting process.

Efficient Dynamic Machine Tool Simulation with Included Damping and Linearized Friction Effects

Friction is a nonlinear phenomenon being present between moving components. For the axis of a machine tool, frictional and control effects have a strong influence on the system’s dynamic behavior. Due to their nonlinearity, frictional effects are usually modeled using time consuming transient simulations. This paper presents an approach to efficiently linearize frictional effects for a given excitation based on the nonlinear behavior of the system. The linear friction models can be used together with linear models of the control for an efficient frequency domain analysis of the dynamic behavior, while preserving high accuracy.

Motion Simulation of NC Machine Tools Considering Rubber Sheet's Property under Machine Bed Supports

Motion Simulation of NC Machine Tools Considering Rubber Sheet's Property under Machine Bed Supports

Plant Layout and Simulation Roaming System based on Virtual Reality Technology

The layout and roaming of machinery and equipment in the workshop is an important development direction of intelligent manufacturing. In this paper, the general process of developing an intelligent factory system are put forward. The 3D models of various kinds of mechanical equipment are established. The textures and maps of the model are processed. The virtual simulation engine is used to establish the workshop map. The roaming work of the virtual workshop is developed based on the map. The space layout of the mechanical equipment and the machine tool simulation cutting system are developed. Comparing with the traditional simulation software, this system takes shorter period of development and achieves better visualization. And combined with the virtual reality technology makes this system more creative.

Integrated approach for milling impeller parts

This paper presents an integrated approach for 4-axis milling impeller parts. Impeller blades are designed with a ruledsurface which is twisted to achieve the required performance. It can affect as an undercut or overcut on the part surface and collisions during machining. A method to manufacture impeller parts on a 4-axis machine is presented. Impeller 3D CAD models are implemented using geometric design parameters and CAM for 4axis Point Milling and Flank Milling are prepared under the SIEMENS UG NX. A postprocessor for desktop 4-axis CNC Mill using MATLAB® and a virtual machine tool simulator using VeriCUT® has been developed. Actual machining for impeller blades are done with Desktop 4-axis CNC Mill for the verification and validation purposes.

Virtual simulation of five-axis machine tool with consideration of CNC interpolation, servo dynamics, friction, and geometric errors

A virtual machine tool (VMT) simulation system which considers tool center point (TCP) interpolation, geometric errors, servo dynamics, and friction effects for a five-axis machine tool is developed in this paper. A novel five-axis interpolation method is proposed to ensure that maximum velocity constraints for each axis can be satisfied. The geometric error model, including lead screw, straightness, angular and squareness errors is built to analyze the volumetric errors within the working space. The model which includes rigid body motion, friction model and servo control loops is utilized to evaluate servo dynamics and non-linear effects. The errors caused by the locations, servo dynamics, and friction effects are integrated into the VMT simulation program. Simulation results of TCP trajectory are represented by small line segments to generate NC codes. Then the NC codes are fed into VERICUT software to perform virtual cutting. To evaluate the interpolation design, cutting experiments are carried out on the five-axis engraving machine with a PC-based controller. The performances using the proposed interpolation method are comparable with the commercial CNC controller from Heidenhain. The effects of different error sources on the surface are demonstrated by cutting the sculpture of a human face. Path overcut caused by servo dynamics is found at sharp corners, and volumetric errors cause obvious tool marks and poor surface roughness. The proposed methodology can serve as a useful tool in evaluating the behaviors of error sources during the design stage.

Friction in feed drives of machine tools: investigation, modeling and validation

Virtual simulation and optimization of the dynamic behavior of machine tools in the development phase is required to satisfy the increasing demands on machine tool performance. While mass and stiffness properties can be simulated with sufficient accuracy, often no suitable damping models are available for the components of machine tools. The commonly used linear damping models are predominantly linear hysteretic or viscous models. However, the linear damping models are often not appropriate to reflect the occurring nonlinear effects in machine tools with the required accuracy. The reason for these nonlinearities are predominantly the friction forces in feed drive components. To resolve these deficits, the friction in feed drive components is comprehensively investigated in this paper, models for friction forces are identified and coupled with a reduced, flexible multi-body system. With the identified friction models the measured friction curves can be reproduced very precisely. The coupled, reduced, flexible multi-body model allows to simulate the nonlinear effects and to predict the dynamic behavior of machine tools with high accuracy. Consequently, a further important step towards accurate virtual simulation of machine tools is made.

Energy Demand Simulation of Machine Tools with Improved Chatter Stability Achieved by Active Damping

The electric base load of milling machine tools has a high share of the machine’s total energy consumption. An approach to decrease the energy demand per workpiece is to shorten the machining time by raising the material removal rate. The maximum feed depends on the tool’s wear resistance while the maximum depth of cut is often limited by the chatter stability of the machine. In this paper active damping is used to damp chatter vibrations, which leads to a higher depth of cut. To evaluate the decrease of energy consumption for any workpiece, a modeling methodology for the energy demand of machine tools was developed, which is presented in this paper. The methodology is able to estimate the energy requirements of the spindle during cutting, of the feed drives, of the auxiliary equipment and of the base load. The numerical results were experimentally validated by different 2.5D machining processes, with good agreement between the simulation model and the experimental results. Therefore, the proposed methodology can be used effectively for calculating the total energy required for the machining of any workpiece. In addition, the structural dynamics of the machine tool, the active damping system and the cutting process were modeled in order to simulate the chatter stability. This enables a straightforward determination of the optimum cutting parameters as well as a comparison of different milling part programs, both in terms of the energy demand. Furthermore, it is possible to evaluate the energy conservation by active damping and to point out for which cutting processes active damping is useful.

A Synchronous Approach for Numerical Simulation of Machine Tools

In this paper, a synchronous approach for dynamic simulation of machine tools is described. Computer Aided Engineering (CAE) method models and analyzes a dynamical parameter prototype of machine tools. In which, the flexible structure, interactive movement, non-linear factor effects as well as characteristics of resonance frequencies and mechanical transfer function are considered. The integrating Finite Element Method (FEM), Multi-Body Dynamics (MBD) and control carries out a solution of machine tools simulation for predicting dynamic machine behaviors. The static analysis and modal analysis of components are presented with sample examples. Cybernetic characteristics like Bode diagram and such a controller are implemented for movement tailors. The synchronous approach deduces a practically technical method for machines tools.

A web-based virtual CNC turn-milling system

This paper presents a different web-based virtual turn-milling system, which aims to address the common problems of existed systems. The system has not only economical value, such as shortening product cycle from design to market, but also scientific interest, like proposing a new trajectory planning method. In other words, it helps sellers and buyers better understand products and enables planners and machinists to make decision or verify CNC codes much more accurate and faster. This system is made up of three levels, which is client browser, server, and database, and every level is divided into several specified functions. Among all the functions, turn-milling simulation function is the most crucial part. To enhance the system’s features, many sub-function modules are also adopted in simulation functions. Through these modules, the system implements material removal function, tool trajectory planning function, numerical control (NC) code inputting and compiling function, and so on. To realize these functions, the whole machining system is developed by using the network superiority of Java language and Virtual Reality Modeling Language (VRML) technology interaction, which will also lead to smaller data volume. Owing to the transportability of Java language and VRML technology as well as the good understandability of the system, this web-based virtual turn-milling system is also suitable to the dynamic demonstration and machining simulation of other NC machine tools. Some future research directions are given to perfect the system in the end.

Compensation of geometrical deviations via model based-observers

This paper presents a rigid body machine tool simulation that is real-time capable and used in machine tool controls to estimate dynamic dislocations. The rigid body model is parameterized by static stiffness measurements and compared with a simulation in a customary software system RecurDyn. Based on the theoretical consideration, a modal analysis is examined in order to determine the damping properties of the test rig and to verify the control model dynamically. The investigated model of the test rig is afterwards implemented in a Kalman filter and transferred into the machine tool control. The performance of this control is assessed by linear movements. Finally, the dependency of the machine tool behavior on the position and load mass is considered by using the control model.

The Simulation and Optimization of Chain Tool Magazine Automatic Tool Change Process

In order to ensure processing quality and validate the accurary of macro program. VERICUT software was often used to achieve five-axis gantry milling machine automatic tool changer (ATC) of the whole process simulation.The results show that the validity of macro program is verified by NC simulation and the efficiency of NC simulation is improved. It provides a guide for the modeling and simulation of multi-axis CNC machine tools.