Spindle Vibration Research Articles

Analysis of the mechanical dynamic performance for the CNC machine spindle remanufacturing

ABSTRACTIn this paper, the CNC machine spindle after remanufacturing is researched as a object on the multi-constrained state. At first, it is established a three-dimensional simulation model for a CNC milling machine spindle system in theory, secondly this article uses the CATIA software of finite element analysis function to analysis the remanufacturing of machine spindle system static. Through dynamic analysis function of CATIA software, it has carried on the dynamic simulation of slender shaft, get the remanufacturing dynamic characteristic parameters of machine spindle system. Modal analysis was carried out on the remanufacturing machine tool spindle system, get the machine spindle system modal frequency and vibration mode in different order number. The paper contrast theoretical analysis and the modal analysis, validate the correctness of theoretical analysis.

Effects of Axial Spindle Vibration on Surface Generation in Ultra-Precision Diamond Turning

In ultra-precision diamond turning (UPDT), axial spindle vibration (ASP) plays a crucial role influencing nanometric surface quality. In this study, a simplified model for ASP is proposed to study its effects on surface generation in UPDT as the spindle is idealized as a mass-spring-damper system. Significantly, the model successfully explains that ASP induces radial patterns at a machined surface. More importantly, this proposed model can be employed to easily predict and understand the effects of ASP on surface generation in UPDT.

3D Fractal Investigation on Ultrasonic Vibration Assisted End Grinding Surface of SiCp/Al Composites

This paper presents a 3D fractal investigation on ultrasonic vibration assisted end grinding surface of SiCp/Al composites. According to variational method, 3D surface fractal dimension is calculated with MATLAB software based on profile data, and evaluates the influence of process parameters on the surface quality. The experimental results indicate that 3D surface fractal dimension increases with spindle speed and vibration amplitude, and decreases with feedrate and cutting depth. A large value of 3D surface fractal dimension corresponds to a better surface finish.

研削品質向上技術の回転軸衝撃力緩和振動低減理論の実証実験

研削品質向上技術の回転軸衝撃力緩和振動低減理論の実証実験

振動抑制のための回転抵抗衝撃力緩和の理論的検証

Rotary resistance as reaction force from the surface of the work via cutting edge which is rotated with grinder spindle causes spindle eccentric rotation where rotation center is distant from the rotational moment minimum center. In this study, the dynamics of spindle vibration by impulse reaction force caused by rotary resistance is investigated by a general vibration theory and the mechanism of how impulse force is mitigated by mass inertia force of a free slide weigh in a flange connected to spindle.

Cyber physical process monitoring systems

Manufacturing process monitoring systems is evolving from centralised bespoke applications to decentralised reconfigurable collectives. The resulting cyber-physical systems are made possible through the integration of high power computation, collaborative communication, and advanced analytics. This digital age of manufacturing is aimed at yielding the next generation of innovative intelligent machines. The focus of this research is to present the design and development of a cyber-physical process monitoring system; the components of which consist of an advanced signal processing chain for the semi-autonomous process characterisation of a CNC turning machine tool. The novelty of this decentralised system is its modularity, reconfigurability, openness, scalability, and unique functionality. The function of the decentralised system is to produce performance criteria via spindle vibration monitoring, which is correlated to the occurrence of sequential process events via motor current monitoring. Performance criteria enables the establishment of normal operating response of machining operations, and more importantly the identification of abnormalities or trends in the sensor data that can provide insight into the quality of the process ongoing. The function of each component in the signal processing chain is reviewed and investigated in an industrial case study.

Tool damage and its effect on the machined surface roughness in high-speed face milling the 17-4PH stainless steel

17-4PH stainless steel is a widely used martensitic precipitation hardening stainless steel, and it is a typical difficult-to-cut material. This paper presents an effort to investigate the insert damage process and its effects on the machined surface roughness during the whole process of high-speed face milling the 17-4PH stainless steel. It was found that although the endurance failure, adhesive wear, and diffusion wear altogether contributed to the insert damage, the insert was more inclined to be damaged by the fatigue breakage at the low cutting speed, and by flaking when the cutting speed increased. Notch wear was found during the cutting process for all the milling tests, and the higher cutting speed could severely accelerate its formation. During the cutting process, the average roughness value and its deviation on the machined surface significantly increased after the notch wear. The spindle vibration and big gap between the cutting edge and the workpiece caused by insert damage could lead to the severe chip winding, and further to the generation of scratches and bulges. In the actual production, it is recommended to periodically monitor the tool wear condition and machined surface roughness during the whole cutting tool life cycle, besides exploring appropriate cutting parameters.

Process Design Method of High Speed and Stable Cutting Hardened Steel

In view of the unstable cutting problem in the process of high speed milling hardened steel. Conduct experiment of the stability of machine tool and high speed milling cutter. The machine tool spindle vibration spectrum and vibration acceleration signal under the condition of different centrifugal force were detected. Obtained the critical speed of security and stability cutting of milling cutter and machine tool spindle. Through the experiment of concave and convex surface of hardened steel high speed milling, obtained the vibration characteristic of machine tool spindle and the shape characteristic of machined surface of hardened steel concave and convex surface. Comparative analysis the experimental results of milling cutter free running and milling hardened steel under the same speed condition. Recognizing the significant effect of inherent vibration characteristics of machine tool to the stability of the hardened steel high speed milling. With the aim of achieving stable and efficient cutting of hardened steel, put forward process design method of high speed milling hardened steel. Using this process design method, obtained the process scheme of high efficient and stability cutting hardened steel die. Process validation results show, the stability of the high speed milling concave convex die of hardened steel improved over 33%.

Performance of High-Speed Precision Air-Bearing Spindle with Active Aerodynamic Bearing

A high-speed precision air-bearing tool spindle with active aerodynamic bearing is proposed for improving the quality of machining using small-diameter cutting and grinding tools. The spindle is basically supported by aerostatic radial and thrust bearings. According to the spindle vibration detected by capacitance sensors, the wedge angle of the active aerodynamic bearing was controlled using piezoelectric actuators, thereby suppressing the spindle vibration. In the present paper, the performances of a prototype air-bearing spindle with single-row active aerodynamic bearing and an improved air-bearing spindle with double-row bearings are reported. Through experiments, it was demonstrated that the maximum rotational speed controlled by the active aerodynamic bearing is 800 Hz (48,000 min-1), and that the amplitude of spindle vibration can be suppressed to <50 nm at the rotational speed of 500 Hz (30,000 min-1).

Investigation of the effects of spindle unbalance induced error motion on machining accuracy in ultra-precision diamond turning

In ultra-precision machining, error motions of the aerostatic bearing spindle (ABS) have significant effects on the machining accuracy. Spindle unbalance is a critical factor attributing to error motions of the ABS. Much work currently has been focused on the measurement of error motions and spindle balancing. However, the unbalance induced spindle error motion (UISEM) and the corresponding effects on machining accuracy are not well understood. In this paper, a dynamics model of the ABS was established to characterize the UISEM and its dynamic behavior with consideration of the unbalance effects. A series of groove turning experiments were especially designed to investigate the UISEM. Good agreement between theoretical and experimental results was achieved, demonstrating the low frequency enveloping phenomenon of the error motions of the ABS, identified as the unique superposition effects of two motion components at high frequency in the spindle vibration. In addition, the experimental result reveals that the relative distance between the rotational axis of the ABS and the tool tip varies with respect to the different spindle speeds, significantly degrading the machining accuracy.

Surface fractal topography-based contact stiffness determination of spindle–toolholder joint

Accurate modeling of contact stiffness is crucial in predicting the dynamic behavior and chatter vibration of spindle–toolholder system for high-speed machining centers. This paper presents a fractal theory-based contact model of spindle–toolholder joint to obtain the contact stiffness and its real contact area. Topography of the contact surfaces of spindle–toolholder joint is fractal featured and determined by fractal parameters. Asperities in micro-scale are considered as elastic or plastic deformation. Then, the contact stiffness, the real contact area, the elastic contact force, and the plastic contact force of the whole contact surface are calculated by integrating the micro asperities. The relationship of the contact stiffness and the drawbar force follows a power law, in which the power index is determined by the fractal parameters. Experiments are conducted to verify the efficiency of the proposed model. The results from the fractal contact model of spindle–toolholder joint have good agreement with those of experiments.

Effect of grinding wheel spindle vibration on surface roughness and subsurface damage in brittle material grinding

The external interference and vibration can seriously affect the machining errors in brittle materials grinding process. This paper proposes a new model to analyze the relationship between surface roughness (SR) and subsurface damage (SSD) depth on the basis of grinding kinematics analysis and indentation fracture mechanics of brittle materials taking the wheel spindle vibration into account. The basic equations, for example, equations of grain trajectory and penetration depth are derived in new forms. Based on the basic equations above, the existing SR and SSD formulae are modified for further study. The effects of grinding and vibration parameters on SR and SSD are respectively analyzed in detail. Results show that both SR and SSD increase with the increase of table speed and vibration amplitude resulting in bad surface and subsurface quality. On the other hand, both the increasing grinding speed and decreasing vibration frequency can improve the quality of ground surface and subsurface with small SR and SSD. In addition, the increase of initial grinding depth and vibration initial phase increase the depth of SSD but have little effect on SR. The penetration depth and distance between grain's tip and finished surface are the two main factors considered to cause the different effect laws on SR and SSD among these parameters. Experiment is carried out to validate the rationality of proposed model. The effect trends of various grinding parameters on SR obtained by our model consist with measured experimental data. The typical subsurface crack system is clearly revealed through the experimental observation on SSD using SEM. Finally, the relationship between the two is fitted utilizing quadratic polynomial. Results show that the SSD depth is nonlinear monotone increasing with SR and the fitting accuracy is more or less affected by both grinding and vibration parameters.

Multi Objective Optimization of Turning AISI 4340 Steel Considering Spindle Vibration Using Taguchi- Fuzzy Inference System

Multi-objectiveoptimization (MOO) of cutting parameters for turning AISI 4340 steel is experimentally investigated by applying fuzzy logicwith Taguchi method. The effect of uncontrollable parameter (spindle vibration) along with the controllable parameters on multiple objectives is studied. Use of uncontrollable factor helped to make the design robust. Coated and un-coated cutting tools and the latest lubrication method (Minimum quantity lubrication) are also considered to match the current scenario of manufacturing system. Fuzzy logic is used to change multiple objectives to a single objective. Regression model is developed for multiple objectives. The data analysis concealed the optimal setting for turning process.

The Research on the Spindle Vibration State Suppressor after Remanufacturing

The overhung spindle system is studied as the object after remanufacturing, the spindle simplified cantilever and the mathematical model was established based on the simplified equivalent device. The simulation analysis of the dual cantilever was carried out by using ANSYS.The vibration mode and inherent frequency of the cantilever, the deformation caused by the applied loads was given in this paper.It is designed by the linear quadratic optimal control of two state regulator through analyzing the vibration form and loading condition,use of independent modal control algorithm based on the detection of the position feedback control,It is inhibited effectively when a cantilever beam subjected to external transient pulse disturbance caused by two order and higher order system mode vibration,and using the Matlab software programming for active vibration control effects simulation.In addition.Matlab software gave the image result of response of vibration system.Both the brief solution program and the accurate image data which corresponded with vibration theory showed the feasibility and superiority during solving these responses of the spindle vibration system after remanufacturing.Thereby,this research provided an easy and effective method to solve the response of general mechanical vibration system.

New machine tool motorized spindle integrated with one electromagnetic ring balancer driven by optimal square wave

Machine tool motorized spindle usually encounters mass imbalance in the operational process. In order to enhance the machining efficiency and precision, on-line active unbalance compensation technique is becoming the first choice of vibration suppression for machine tool spindle. This paper proposes a new motorized spindle integrated with one electromagnetic ring balancer. Firstly, the three-dimension structural design of the integrated spindle is described in detail. Then, the balancing principle of electromagnetic ring balancer is set forth. In order to disclose the structural characteristic and determine the reasonable square wave drive parameters, the finite element calculations are carried out to obtain the relationship between the torque and rotational angle of counterweight disk when coil is not electrified, and the movement curve when coil is applied different currents. Based on the steady-state and transient electromagnetic field simulations, a specific spindle prototype with one electromagnetic ring balancer is developed. For the prototype, vibration test rig is built to verify the balancer design correctness, fabrication quality and vibration reduction effectiveness. The experimental results show that the proposed balancer has a smooth movement process under square wave drive, a desired unbalance response and the spindle vibration can be effectively reduced in a semiautomatic balance way, which is very beneficial to the improvement of operational precision and service life of machine tool motorized spindle.

Study of variable depth air pockets on air spindle vibrations in ultra-precision machine tools

The low vibration of air spindle is a very important thing to achieve nanometer accuracies in the products of machined parts in nano-machining. Compared to the common air pockets with constant depth used in air cells of ultra-precision machines, this paper studied some special air pockets including five variable depth modes: flat, conical, pyramidical, spherical with two sphere radii. Considering rotational speed as well as these parameters, 18 experiments have been committed using a lathe machine. From experiment results, the air spindle with air pockets of pyramidical depth at a low rotational speed has minimum vibrations.

The Research and Design of Virtual Spindle Vibration Test System

In order to facilitate dynamic analysis of spindle, improve the vibration characteristics of the spindle and achieve the goal of control of spindle motion stability. A spindle vibration testing system is developed with necessary sensor, signal conditioner and data acquisition card based on Labview software in this paper. The spindle vibration testing and analysis system is formed based on virtual instrument graphical programming language Labview. The hardware is reduced in testing process. At the same time, acquisition, processing and analysis for vibration signal are realized, and the costs of hardware are greatly reduced. The testing work is made more convenient and quick by this system, and test is made more intuitive by its real-time display function. It will provide a scientific basis for searching for measures to reduce the spindle vibration and developing a new generation of mechanical structure of the spindle.

The Design of a New Type of Spindle Vibration Test Device

In this paper, a set of spindle vibration test equipment has been designed by using modern design method, on the basis of in-depth study of spindle vibration source .The device includes three parts: machinery, detection and control .In the mechanical part, using sensor fixed machine mobile systems, the design of the spindle drive part and test board was carried on respectively .In the detection part ,the virtual instrument Labview graphical programming language was adopted to form a spindle vibration test and analysis system, realizing the acquisition, processing and analysis of the vibration signal .In the control part, Yan Hua movement control cards are adopted to realize control of motor speed, through Labview programming.

Study on Grinding Force Model in Ultrasonic Vibration Assisted Grinding for Ductile Materials

Ultrasonic vibration Assisted Grinding (UAG) is an effective processingmethod for difficultmachiningmetalmaterial.This paper put forward a new model to predict the grinding force in UAG. The paper presents the abrasive grain motion equations, removal rate model,grinding force model and grinding force ratio model.According to the grinding force model, the grinding force will decrease as the spindle speed, vibration amplitude and vibration frequency increase. The grinding force increase as the grinding depth and feed rate increase.

Application of Mathematical Morphology Filter in Non-Stationary Signal of the Spindle Dynamic Balance Regulator Online Adjustment Process

The signal which is generated by the dynamic balance regulator for unbalanced spindle in the process of adjustment, having strong nonstationarity. The traditional signal processing methods could not deal with these signals, but also could not express the processing of signal changes. Aiming at the problem, a method combining mathematical morphology filter and the short-time Fourier transform is applied in the non-stationary signal processing in this paper. Using mathematical morphology filter could reduce the noise of spindle vibration signal, and improve the SNR. The amplitude of spindle vibration signal could be got by means of short-time Fourier transform method. Utilized the method proposed in this paper, non-stationary signal of the spindle dynamic balance regulator online adjustment process has been analysed, the results of the experiment show the feasibility of the method.