Abstract: Surface roughness is an important evaluation index of the machined surface quality. The ultrasonic turning mechanism was described in detail and the mechanism reducing surface roughness in ultrasonic vibration turning was obtained in this paper. Meanwhile, ultrasonic turning experiments were carried out to verify the theoretical analysis. Theoretical and experimental research results show that machined surface roughness of quenched steel in ultrasonic turning is very close to geometric surface roughness, resulting in smaller surface roughness than that in ordinary turning.
Abstract: This 3D optical metrology has become a standard tool in industrial process chains by providing fast and precise full-field 3D data for quality control, rapid manufacturing and reverse engineering applications. In this report, the trend that 3D optical metrology has widely used by the product development is described. Concretely, it is described to inspect shape on the free-form surface, to digitize the design model, to manufacture solid shape without CAD model, to define CAE model from real shape, to make analysis for sheet metal components, and to make real-time strain measurement for tensile tests.
Abstract: Based on the simplex style of the traditional medical beds at home and abroad presently, a new folding mechanism of multifunctional medical bed was presented. After theoretical analysis, an optimal structure was selected. This mechanism consists of several planar four-bar linkages. It has one degree of freedom, which means it can be driven by only one driving torque to achieve multi-states changes. Therefore, it could save the space and reduce the weight of the bed as much as possible. The analysis of mechanism was carried out, simulation and stability were performed as well. A proto was established in the software named Automatic Dynamic Analysis of Mechanical Systems (ADAMS) to verify feasibility of the mechanism and the correctness of the design principle. It is an ingenious and brief design, which provides useful information for future research about folding medical bed.
Abstract: In this paper, the influences of applied magnetic field on flow state during electroforming of the high-aspect-ratio (HAR) blind micro-hole were numerically analyzed using the Fluent software. The results showed that, when microelectroforming of nickel without external agitation, three vortexes could form due to the magnetohydrodynamic (MHD) effect within the HAR micro-hole with magnetic field in parallel to cathode-electrode surface, and the flow rate in the micro-hole increased with the increase of the magnetic field and current density. The MHD effect helped to enhance mass transfer during the microelectroforming of HAR microstructures.
Abstract: A dynamic model of the spindle-cutter coupling system is established including the gyroscopic effects and shear deformation. Dynamic characteristic of the system is analyzed by utilizing the whole transfer matrix method (WTMM) based on the Riccati transformation, and strain energy distribution of the system is estimated. Dynamic characteristic of the system is optimized by univariate search technique. And optimal path in the system optimization is provided. According to the optimal path, a method of local mode elimination by decreasing stickout length of the milling cutter is proposed. The calculation results indicate that preload level of front bearing and rear bearing is the key factor of dynamic optimization after local mode elimination.
Abstract: Straightening of machining deformation of the aeronautical monolithic components is one of the most complex manufacturing problems encountered in modern aerospace industry. In this paper deformation straightening processes are simulated using finite element method and the integrated simulation environment is put forward. A new method combining response surface method (RSM) with finite element simulation is proposed in order to quickly predict the straightening results in certain design space. The response surface about springback was constructed based on simulation results.
Abstract: In this paper, a novel type compact five-coordinate measuring machine with laser probe, which contains three translational axes and two rotational axes, was designed and built. The overall mechanical structure and several key components are introduced in detail. The structure form of column and cantilever beam is adopted, which enhances the measuring flexibility and make the probe feasible to detect the objects from various directions. With the help of results of finite element analysis on the beam, the method of pre-deformation assembly is employed to guarantee the location accuracy of the probe. Using a standard ball, the calibrating results show that the uncertainty of this machine is within 2.2
Abstract: Radial ring rolling is an unsteady plastic deformation process. Internal stress of the ring is foundation of formation of the plastic hinge. The radial wall thickness of ring changes gradually along ring circumferential direction. Theoretical analysis and FE simulation show that: the plastic hinge is not always exactly opposite to the rolling deformation zone in ring rolling process without guide-roll. The plastic hinge position angle β0 is affected by ratio of rolling entrance wall thickness H0 and rate of wall thickness change η. Curve of β0-H0/η is shaped as double U staggered relative to each other. With the H0/η increasing, β0 reduces gradually and approaches to π in the range of H0/η>6.28. H0/η>14.6H0/R2. Only when the rolling process is steady, and H0≈R2, β0 is greater than π, and approximates to π. The β0 fluctuates dramatically when H0/η≈5.71. In some cases, H0/η may fluctuate in 0 to 6.28, leading to the instability of plastic hinge position.
Abstract: In order to improve VSR(Vibration Stress Relief) effect, finite elements method is applied to study VSR process factors. Simulation on moulding process, rough machining process and heat treatment are used to study the residual stress distribution of casting. The modal analysis is carried out to determine exciting frequency, exciting position and support position. Based on residual stress distribution, harmonic response analysis is applied to find relationship between dynamic stress and exciting force. Then the exciting force can be determined. The research results indicate that finite elements method can be used to determine VSR process parameters quickly and accurately.