Simulation in design air spindle with orifice and distribution grooves

This paper presents some results of simulation using ANSYS CFX software in design air spindle which has the structure in the form of orifice and grooves to ensure uniform pressure distribution and avoiding air hammer; it is also easy to manufacture and reduces costs. The results of simulation are good in investigating operation of air-spindle which is changed some parameters to find the optimal working mode for the air spindle with speed in the range of 5000–20,000 rpm.

Material Flow in Lap Joint of Dissimilar Metallic Foils by Friction Stir Diffusion Bonding with Micro Indentation

Friction stir diffusion bonding (FSDB) has been applied to lap dissimilar foils joints of aluminum alloy on top of commercial purity (CP) titanium. FSDB of the foils was successfully performed through stirring only the upper aluminum foil by the air spindle with an extremely-high rotation speed of 105,000 rpm. By using smooth surface of the tool tip, FSDB with micro indentation less than or equal 10μm could be carried out to improve the surface condition of the joint and the indentation depth required for joining was reduced. The material flow of the upper aluminum alloy foil in the FSDB was investigated by deposited platinum-palladium as the tracer material on the surface of the lower titanium foil. Then it was confirmed that the vestiges of vigorous stirring appeared in the region given at a distance from tool center while little vestiges was found in the other region. These regions seemed to be bounded by a radius of about 0.6 mm from the tool center. Moreover, the bonding strength distribution as a function of the distance from the tool center was likely correspondent to the stirring state.

Research on a Hierarchical and Simultaneous Gravity Unloading Method for Antenna Pointing Mechanism

This paper presents a hierarchical and simultaneous gravity unloading method. An air bearing gravity unloading facility for two-orthogonal-axis antenna pointing mechanism (APM) is designed based on this method. This method is proposed based on the characteristics analysis of the two-orthogonal-axis APM and air bearings. The mechanism of the hierarchical and simultaneous gravity unloading method is described in detail. It solves the coupling problem of two axes and unloads the gravity of both joints hierarchically and simultaneously. The air bearing gravity unloading facility which is a structure mechanism with two layers based on this method is designed with planar air bearing and air spindle. The structure of the facility is described in detail. The dynamic models of the APM with its load in space environment and on the air bearing gravity unloading facility are derived respectively. With the analysing of the driving torques and vertical forces of the APM joints in both models, the results demonstrate that the gravity unloading facility can simulate the microgravity environment successfully. This conclusion is also proved by the dynamic simulation with ADAMS software. The simulation also provides some optimization targets for the gravity unloading facility. At last, the gravity unloading facility is established and some experiments are done. The dynamic models, the simulation results and the experiments all show the effectiveness of the hierarchical and simultaneous gravity unloading method.

Development of optical choppers for time-resolved measurements at soft X-ray synchrotron radiation beamlines

Two types of optical choppers for time-resolved measurements at synchrotron radiation soft X-ray beamlines have been developed. One type uses an air-spindle-type rotation mechanism with a two-stage differential pumping system to maintain the ultra-high vacuum of the X-ray beamline, and the other uses a magnetic bearing. Both can be installed at the soft X-ray beamlines at SPring-8, greatly improving the accessibility of pump-and-probe spectroscopy. The combination of X-ray chopper and pump-and-probe photoemission electron microscope at SPring-8 provides drastic improvements in signal-to-noise ratio and resolution compared with techniques using high-voltage gating of channel plate detectors. The choppers have the capability to be used not only at synchrotron radiation facilities but also at other types of soft X-ray and VUV beamlines.

A Proposed Ultraprecision Machining Process Monitoring Method Using Causal Network Model of Air Spindle System

Future ultraprecision machining systems require inprocess monitoring and intelligent machining control functions. This paper presents a newly developed machining process monitoring method. The method proposed aims at monitoring the ultraprecision machining process using a causal network model of an air spindle system. The results of actual machining experiments confirm that the proposed method can estimate the dynamic and thermal behaviors at the cutting point during machining. In consequence, the process monitoring method proposed can systematically predict the tool wear, the contact condition between the tool and the workpiece, the abnormal machining conditions, and so on.