Chun Gen Shen

Stiffness of HSK tooling system in high speed machining

The stiffness of the HSK tool system directly influences the efficiency and the quality of high-speed machining. Based on the mechanics of materials and finite element method, theoretical analysis and digital simulation are done with the stiffness of the HSK tool system. An equation to calculate the deformation angle of the HSK shank is proposed. The basic change law of the stiffness of the HSK tool system is shown and it offers theoretical base for properly applying the HSK tool system to maximize benefit. It is important in theory and application area to develop new-style tool system with our own intellectual property.

Determining Structural Modes of HSK Tool System Based on FEM and EMA

In this research, we computationally analyzed the structural modes of an HSK63E type tool system and verified the results with experimental modal analysis (EMA). The computation was implemented using the finite element method (FEM) based on a linear-elastic theory, with which we computed the natural frequency and obtained the modal shapes under both free and operating conditions. With the method of experimental modal analysis, we also obtained structural modal parameters including the natural frequency, modal shapes and damping ratio under the same free and operating conditions. The computational data were compared with the experimental findings. The reasonable agreement between the two data sets indicated the validity and provided a theoretical basis for using computational methods for determining the natural characteristics and influencing factors of HSK tool system. With this validated FEM model, further analyses were performed to evaluate the unique dynamic performance of the HSK tool system, and to apply dynamic optimum design to other types of HSK tool system.

The Effect of Clamping Force on Static and Dynamic Characteristics of Spindle-Tooling System

This paper investigates the effect of spindle clamping force on the static and dynamic characteristics of the spindle-tooling system through measuring the frequency response function of the tool end point in variable spindle clamping force. The research shows that the limited static stiffness increases accordingly and normal static stiffness changes little as the spindle champing force increases. The high spindle clamping force leads to reduce the modal damping of the spindle-tooling system while the natural frequency varies slight. The analyses of process stability indicates that the low spindle clamping force can improves the process stability because of the higher damping in some clamping force range.

Modal Experiment and Analysis of HSK Tool-Holder and Thin-Disk Cutter

On the basis of modal analysis theory, a free modal test and a work modal test of the HSK tool holder and thin-disk cutters with the vibration measuring method were carried out. The modal parameters such as inherent frequency, damping ratio and modal shapes were gained. These modal parameters were compared with modal parameters, which were gained with the finite element method. The results verified whether the construction of the finite element modal was reasonable or not, and provided technical help for exploring the dynamic characteristics and structural optimization of HSK tool system, making the full use of HSK tool holder in high- speed machining.

Analysis and Simulation of BIG-PLUS Tooling System

A new finite element model of BIG-PLUS tooling system are made, the BIG-PLUS tool holder and spindle deformation owing to centrifugal force generated by displacement, as well as different speed and clamping force of the radial displacement are analyzed and simulated. The results show that the radial clearance and deformation between spindle and tool holder can expand as the rotating speed increases, enhancing the clamping force and the shank of the spindle positioning accuracy and reliability of connection.

Determining Structural Modes of HSK Tool System and Influential Factors

The mode analysis of the HSK tool system structure is the base for determining HSK high speed spindle-tool system dynamic performances. In this paper, considering the HSK63A tool system as the research object, by way of the dynamic finite elements analysis method (FEM), the finite element assembly model of HSKA63 tool system was established, the natural frequencies and the modal shapes were obtained under the free condition. Then, with the method of experimental modality analysis (EMA), the FEM results were determined whether the construction of the finite element modal was reasonable or not, the factors were discussed, such as tool diameters, tool length, connection conditions of shank and cutter etc, which affected the mode parameters of HSK tool system structure. The computing results can be offered for evaluating the tool system’s dynamic performances as the theoretic evidences.

Analysis and Testing of the Dynamic Performance of Tooling System

In this research, a linear-elastic FEM (finite element method) model of tooling system under the unconstrained condition was established for a BT40 tooling system. The natural frequency and the modal shape of the tooling system computed from the FEM analysis were verified against the structural modal parameters obtained from experimental modal analysis. In the basis of rational FEM model of tooling system, the changing law its length and diameter influence to structural modal parameters was investigated. After that, with the machine vibration testing of spindle raising speed idle running, further study on the law about the changing length and diameter of tooling system influence to vibration characteristic of spindle-tool system, the researched results will be a theoretical basis to evaluate the dynamic performance of other type’s tooling system.

A Theoretical Investigation on the Capillary Model of Lubricant Penetration

In metal processing, lubricant penetration process can be explained by the capillary model theory. Observed through microscope, cylindrical capillary model was chosen and was analyzed on the basis of hydrokinetics. Moreover, it was indicated of the basis for dividing the entire penetration process. Based on kinetic theory of gases, the penetration of gas-liquid two-phase flow in minimum quantity lubrication (MQL) machining was simply analyzed and it was pointed out that there was only gaseous phase filling process.

Experimental Investigation on the Influence of Tool System Imbalance on its Vibration Characteristics

Due to particular structural design, the error of manufacturing and other factors, the tool system will have more or less residual imbalance. The spindle-tool system’s vibration signals and its frequency response structure were made as reference under the testing of machine raising speed idle running, firstly the tool system’s amount of imbalance was adjusted with the aid of the special balancing ring, then the spindle-tool system’s vibration characteristic was obtained under various amount of imbalanced in idle running condition, finally making use of frequency spectrum analysis the influence of unbalanced quantity to spindle-tool system’s vibration characteristics was studied and compared, the results and the researching approach can help to find the rules about the influence of tool system imbalance to its vibration characteristics in higher speed condition.

Analysis of Cutting Forces in Precision Turning Based on Oblique Cutting Model

In this work, the prediction and analysis of cutting forces in precision turning operations is presented. The model of cutting forces is based on the oblique cutting force model which was rebuilt by two coordinate conversions from the orthogonal cutting model. Then the cutting field in precision turning was divided into two fields which are characterized as curve change and linear change on cutter edge and they were modeled respectively. Cutting field of cutter nose was modeled by differential method and its cutting force distribution is predicted by the proposed method. The predicted results for the cutting forces are in agreement with the experimental results under a variety of operation variables, including changes in the depths of cut and in the feedrate.