Advanced Materials Research Vols. 690-693

Abstract: The effect of potassium peroxydisulfate-sodium hydrogensulfite (K₂S₂O₈- NaHSO₃) as an initiator system in H₂O₂ –based slurry for the abrasive-free polishing (AFP) of hard disk substrate was investigated. The polishing experimental results showed that the H₂O₂-K₂S₂O₈-NaHSO₃ slurry had ten times higher material removal rate (MRR) than the H₂O₂ slurry in AFP of the hard disk. Further, the polishing mechanism of H₂O₂-K₂S₂O₈-NaHSO₃ slurry was investigated. Compared with the H₂O₂ slurry, electron spin-resonance spectroscopy (EPR) analysis showed that the H₂O₂-K₂S₂O₈-NaHSO₃ slurry provides twenty times higher concentration of hydroxyl free radical. Potentiodynamic polarization measurement showed that the corrosion current of disk substrate in the H₂O₂-K₂S₂O₈-NaHSO₃ slurry is larger than that in the H₂O₂ slurry. The results imply that K₂S₂O₈-NaHSO₃ as an initiator system for H₂O₂–based slurry has application prospects in abrasive-free polishing.

Abstract: Aspheric detection technology has always been the key factor which affects the further enhance of aspheric precision manufacturing. Without high-precision detection methods and instruments to fit processing accuracy, aspherical precision machining and ultra-precision machining is difficult to achieve. A contact measurement of aspheric surface detection technology and its error analysis are mainly introduced in this paper, and testing equipment is the UK Taylor Hubson profilometer with instrument precision 0.2μm and measure the caliber 200mm.

Abstract: For the deep-hole drilling is in closed or half-closed condition and the cutting situation can’t be controlled directly, it brings a big challenge to attain the machining precision. Deep-hole honing is an effective process method that can ensure the precision of size, geometry shape and surface quality. A new machining technologies of finishing honing on precision deep-hole are discussed. Two typical machining examples were illustrated, and the machining effection were also discussed. The key technology and chief feature of strong honing were analyzed through honing experiment of titanium alloy and PH stainless steel. The experiments indicate that strong honing is one effective method to solve the problem of precision deep-hole machining of difficult-to-cut materials and the honing tools which was used in the experiments have the feature of good rigidity, high cutting efficiency.

Abstract: The role of K₂S₂O₈ (KPS) initiator on the material removal rate (MRR) of hard disk substrate in the H₂O₂-based slurry was investigated. Experiment results indicate that the MRR of slurry containing KPS and H₂O₂ is higher than that of slurry containing only H₂O₂ under the same testing conditions. The electrochemical test shows that KPS can increase the corrosion rate of hard disk substrate in the H₂O₂-based slurry. The electron spin-resonance spectroscopy (EPR) analysis shows that KPS, as an initiator, can increase the number of OH• free radical. Further, the reaction mechanism of KPS in abrasive-free polishing of hard disk substrate is discussed.

Abstract: Electrochemical deburring (ECD) was used to remove burrs, which exist in the intersections of the miniature drilling holes and the inner wall of stainless steel pipe. Via experiments, the influences of the processing parameters on the deburring quality and the change law of the voltage between the electrode and workpiece were explored, such as process time, electrolytic composition, concentration. The ECD results showed that the burrs can be removed with good quality and efficiency in the condition of optimal selecting parameters.

Abstract: Chatter easily occurs in machining, which is influenced by many factors. The power ultrasonic vibration honing equipment is taken as the research object. The dynamic friction is studied and the dynamics model is established based on the Stribeck model. The describing function of the ultrasonic honing friction characteristics is calculated. The stability of ultrasonic honing nonlinear system is analyzed. The conditions are studied, on which chatter occurs. The expressions of chatter amplitude and frequency are given. The research provides the theoretical basis on which chatter can be effectively avoided when ultrasonic honing equipment is designed.

Abstract: In a multiple probes scanning system for a high precision straightness measurement, the lateral setting error between probes is ignored generally due to the average effect in the range of the aperture of the probes. In this paper, we study a two displacement sensors scanning system. Firstly, the principle of two-point method which is based on the natural extension method is introduced. Then, the influence of the lateral setting error between two probes is analyzed quantificationally when the discrete Fourier transform algorithm is applied. It is shown that a relative evaluation error within the range of 1% can be obtained if the lateral setting error is smaller than 1.5% of the sampling interval as long as the spatial wavelength of the evaluated profile is longer than the probe interval. The effectiveness of the results of the quantitative analysis is confirmed by computer simulations.

Abstract: By taking the belt spindle of the machining center high speed and high precision as the research object, using the finite element method, the Solidworks software is used to make the thermal analysis. In this paper, we define the boundary conditions and thermal load of the spindle thermal analysis, and establish the finite element model. The steady-state thermal analysis and temperature rise is simulated, and the temperature distribution is predicted by using Solidworks software. The results show that the structural design of the belt spindle is reasonable, and the temperature rise is in the control range.

Abstract: In order to improve machining accuracy of machining center, the effect of geometric error on machining accuracy was researched by multi-body system theory. Taking a vertical machining center as example, topological structure of the machining center was described by lower body array. Geometric errors of the bodies in the multi-body system were expressed by homogeneous coordinate transformation. Error model for machining accuracy was deduced and geometric errors having great influence on the machining accuracy were identified. The research results show that, straightness errors and linear displacement errors in three directions have direct influence on machining accuracy, and the effect on machining accuracy caused by angle errors are related to the dimensions of the machining center and travel distance of the three axes. The research results provide guidance for analysis on sensitivity of geometric errors.

Abstract: In view of the complexity of the gear measurement center and its error calibration, the paper put forward the basic concept of a virtual gear measurement center, and analyzed the compositon of the virtual system. The virtual gear measurement center can be used to simulate the real gear measurement process and quantitatively analysis the effects of error, so as to calculate the measurement uncertainty. The application of the virtual gear measurement center was discussed.