Ming Sheng Jin

Comparative Study of Magnetic Abrasive Finishing in Free-Form Surface Based on Different Polishing Head

Nowadays, researches concerned magnetic abrasive finishing (MAF) are becoming increasingly popular. Polishing head is one of the most important factors in the whole polishing system in which magnetic abrasive act directly on the workpiece. In this paper, two kinds of polishing heads applied in the polishing of free form surface are proposed. They are hard polishing head and soft polishing head, respectively. And some important factors are contrasted such as selfsharpening capacity, morphology distribution, and removal uniformity. Moreover, the finishing force is the key factor which is different between the two polishing heads having a great influence on polishing effect. Through comparison and analysis, the soft polishing head is better to finish free form surface. And the experimental results reflect its superiority in polishing free form surface.

Application of Magnetic Abrasive in Gasbag Polishing

Application of magnetic abrasive to the field of finishing processes is increasingly popular and important. Magnetic abrasive finishing (MAF) is effective in precision machining of non-planar workpieces. To study the control of working abrasive morphology and the valid way to solve “incline effect” which is common in some industrial field, application of magnetic abrasive in gasbag polishing is presented. Besides, the polishing system is introduced, and the important factors which influence the magnetic abrasive polishing are studied. Then some tentative experiments are carried out to study its polishing effect. It is found that the difference of surface roughness value and material removal rate under different bevel angle is in small range, which indicates this approach is useful in solving “incline effect”. The work in this paper is also a good attempt for further study that polish precipitous surface of mould or other products.

Spinning- Inflated-Ballonet Polishing Tool and its Application in Curved Surface Polishing

In this paper, a novel spinning-inflated-ballonet polishing tool for curved surface of mould is proposed. The head of the tool is a spherical spinning-inflated-ballonet whose inner air pressure can be controlled on-line and the head surface is covered with a suitable polishing cloth. The head can be rotated in high speed driven by an electromotor or high pressure airflow and its rotating speed can be adjusted. The flexibility of the head, the polishing force in radial direction and the contact area between the head surface and the curved surface of the work-piece can be controlled by adjusting the feeding deepness and ballonet pressure of the tool. The structure and the polishing mechanism of the novel polishing tool are introduced. The application of robot polishing system based on the novel polishing tool also is discussed. Finally the polishing control strategy of curved surface is researched.

A New Method of Pulse Technique in Gasbag Polishing

Gasbag polishing is an automatic, flexible, controllable and practical technique, which has wide application prospect. A pulse technique based on robotic gasbag polishing system is proposed. Its main principle is to use the Pulse Width Modulation (PWM) technique to control the switching time of High-speed Solenoid Valve (HSV). It can not only control the internal pressure of gasbag, but also make the rubber gasbag present pulsation with PWM technique. Moreover, the performance of pulse technique is presented and the effects of different frequency pulse pressure on the polished surface roughness are analyzed through a series of experiments. At last, experimental results show that the pulse technique can improve the polished surface roughness more rapidly in certain extent with appropriate pulse frequency and process parameters comparing with conventional gasbag polishing way.

Modeling and Experimental Study of Magnetorheological Flexible Gasbag Polishing

Magnetorheological flexible gasbag polishing based on the special application of magnetorheological fluid (MRF) in robotic gasbag polishing technique is a novel efficient approach in the field of mould finishing. It can control the polishing pressure by changing the magnetic force generated by MRF inside of the gasbag with the effect of variable magnetic field of electromagnetic coil. Its mathematical model is established to study the main factors influencing the material removal. The orthogonal tests are applied to analyze these important parameters. From the experimental results, it can be seen that this new approach is desirable in realizing the control of surface figure accuracy and improvement of surface quality under certain condition.

Magnetorheological Flexible Gasbag Polishing Technique

Combining the advantages of rheological behavior of magnetorheological fluid (MRF) and flexibility adjustability of rubber gasbag, a magnetorheological flexible gasbag polishing technique applied to free-form mould is proposed. With the development of robotic gasbag polishing technique, the flexibility of rubber gasbag can be adjusted by three methods of changing its internal pressure controlled through a pressure control unit, its own material property and structural parameter, and the rheological behavior of MRF inside of it in response to the application of an alterable magnetic field. Effect of rheological behavior to the flexibility of rubber gasbag and surface quality of mould is the single most important focus in this paper. The magnetorheological flexible gasbag polishing system is established and rheological behavior of MRF with magnetic field is described. Through polishing experiment focusing on the relationship between the surface roughness and current around electromagnetic coil, it can be obtained that magnetorheological flexible gasbag polishing technique is effective to improve surface quality when increasing current around coil in certain extent.

Dynamic Numerical Simulation of Mould Free-Form Curved Surface Gasbag Polishing

Polishing is an important technics processing in order to obtain the high quality surface of mould in industry mould manufacture. For the moment, polishing of the free-form curved surfaces of mould is performed by manpower. So it is important to research gasbag polishing technology. This paper has been developed dynamic numerical simulation for gasbag polishing process based on the new type of polishing tools by FEM. On the material removal theory, influence of the shape of the structure of the gasbag, angular velocity and the air pressure inside the air gasbag on the campaign polishing process are explored. It can be used to provide technology support to establish polishing process database.

Study of the Removing Depth of the Polishing Surface Based on a Novel Spinning-Inflated-Ballonet Polishing Tool

In the field of the mold-curved free surface polishing, how to control the removing depth of the polishing surface exactly is one of the important problems to be solved. In this paper, a mould automatic polishing system that is developed on Motoman-NL20 robot is used to make theoretical analysis and experimental research on the removing depth of the polishing surface based on a novel Spinning-Inflated-ballonet Polishing tool for curved surface of mould. Firstly, FEM (finite element analysis) software is used to emulate three kinds of situation in the process of polishing, then the model of surface removing depth of SBCT polishing is established. At last, through the analysis and comparison, the result of emulation and experiment has a remarkable consistency which accords with the model established by formal theory. This indicates the correctness of the model.

Dynamic Characteristic Difference on Two Kinds of Broading Machine on the Similar Configuration

This paper focuses on the dynamics characteristic difference on the two kinds of broading machine, the workpiece moving and the cutting-tool moving. There is 0.002mm thickness of oil-film clearance between the mobile and immobile components of the broading machine. Hydraulic pressure derived from the driving oil cylinder drives the workpiece or cutting-tool moving, while the material on the workpiece is cutting. Cutting-tool of the machine is an external expand cutter with the groove for breaking the cutting waste, the manufacturing phase is a pulse impact cutting exciting applying on the broading machine correspondingly. On manufacturing, natural characteristic of the broading machine is approximately the pulse impulsion frequency of the machine;response amplitude of the lather is increasing manifesting. The study is focused on the dynamics characteristic of two kinds of broading machine, the difference is workpiece or cutter moving, to predict the manufacturing performance.

Numerical Investigation on the Micro-Slip along Friction Interfaces

Damping in built-up structures is often caused by energy dissipation or energy loss due to micro-slip along frictional interfaces interaction, which provides a beneficial damping mechanism and plays an important role in the dynamics vibration behavior of such structures, especially the contact stiffness and damping coefficient accounting for the kinematics joint. A detailed study the mechanics derived from the interaction interface between the different components has some embarrassment. And a careful study on the micro-slip phenomenon has been carried out using the finite element method. A classical joint configuration, the plane translation joint, has been used as the model problems. The focus of this paper is to evaluate the effect of dry friction coefficient, the external mechanics on the damping response of frictional joint interfaces interaction, to understand the evolution of the slip-stick regions along a joint interface during loading, and to quantify the amount of energy dissipation/loss during cyclic loading and its dependence on structural and loading parameters.