Key Engineering Materials Vol. 679

Abstract: A finite element model based on Abaqus/Explicit is built. Micro cutting mechanism of Al7075 with different cutting depth is simulated and analyzed. The simulation results show that if the cutting depth is more than 10μm, the chip is a kind of continuous curl. If the cutting depth is less than 10μm, the chip is a kind of feathery squeeze debris. When the cutting depth is very small (3μm), the shape of chips is just like discontinuous wrinkle. By contrasting the simulation results of cutting force with its theoretical values, they have the same result. The model of the chip prediction could achieve ideal simulation results.

Abstract: This paper introduced a kind of micro/nanomotion platform. The platform mainly includes 12 flexible hinges, piezoelectric ceramic driver (PZT), motion platform (loaded platform), pre-tightening force adjusting screw and so on. The orthogonal experiment method was used to the output displacement of the micro/nanoplatform. The relationship among the voltage, pre-tightening force and output displacement of the platform was analyzed. The factor level table of the output displacement was produced. The experimental system was established by Laser interferometer and pressure sensor, then the output displacement was obtained when the voltage ranges from 0V to 150V on the condition of every force (20N, 40N, 60N, 80N and 100N). The experimental result lays the foundation for the regression analysis of the output displacement of the platform.

Abstract: This paper develops a three dimensional (3D) simulation system with QT platform and OpenGL 3D library by adopting the driver and Aerotech’s linear motor as hardware platform and INtime and A3200 controller as the software platform. The system uses numerical control (NC) code syntax checking module to test the NC code syntax and applies 3D simulation module to display the actual machining process. The interference and collision detection module is built in this system to detect the problem during the actual processing. The system therefore contributes to avoiding the trial and tests for the ultra-precision machining process and improving the machining efficiency as well as reducing the loss of ultra-precision components of machine tool due to the collision.

Abstract: The paper presents a review on the current situation of diamond tool ultrasonic vibration cutting ferrous metal. The key technology of diamond tool ultrasonic vibration cutting ferrous metals is presented in this paper and the influence of the processing environment of the presence of carbon atoms protective gas, the presence of carbon particles coolant of temperature control technology, ultrasonic vibration, workpiece material surface pretreatment or without on diamond tool wear rate and workpiece surface quality, the relationship between diamond tool wear rate, the workpiece surface quality and the ultrasonic vibration technology, processing environment, workpiece material surface pretreatment technology factors is given. Propose research direction and research emphasis on reducing diamond tool wear rate and improve workpiece surface quality.

Abstract: Tool wear measurement has drawn a significant of attention in the past decades. However, no research has been found on the investigation of tool wear measurement in ultra-precision raster milling (UPRM) process since it is a relative complex cutting process. In the present study, tool wear characteristics were identified by using cutting chip morphologies and a groove cutting. Tool wear investigation using cutting chips is effective because diamond tool wear characteristics can be directly imprinted on the cutting chip surface. Through the inspection of chip surfaces, the profile and location of the tool fracture can be identified. Also, through the groove cutting, the cutting edge retreat due to the tool flank wear can be identified. In this research, a mathematical model was established to calculate the tool retreat. The experimental result shows that the proposed tool wear investigation method is an effective method.

Abstract: The technique utilizing single-frequency laser interferometry has very high measurement accuracy, but it has rigorous requirements for optical design which is affected by many factors. In order to achieve single-frequency laser interferometry with large stroke and high precision, the integral layout, the polarization phase shifting technique and the common mode rejection method are adopted to design the length interferometry system. This paper analyzes factors and design requirements which affect measurement accuracy with large stroke. Based on polarization phase shifting technique, the system employs the four-beam-signal detection technique and the common mode rejection method, to make a differential processing of four mutually orthogonal signals. Thus, the influences of zero-drift of intensity and environmental change on system are reduced. Combined with a 200 phase subdivision, the system achieves the resolution with 0.8 nm. Under the VC++ environment, the displacement measurement results are compensated and corrected according to the environmental parameters. Compared with the Renishaw XL-80 laser interferometer, the system has better stability in short term. In the measuring range of 60 mm, the effectiveness of the system is verified.

Abstract: A macro-micro composite positioning stage with high acceleration and high precision is presented in this paper. A linear voice coil motor (VCM) is used to generate the macro motion, and a piezoelectric (PZT) actuator is adopted to drive the micro stage to achieve a precision micro motion, while PZT actuator can also be used to compensate the position error. A high-resolution grating is integrated into the stage to establish the closed-loop feedback. To research the mechanical dynamic characteristic of the stage, the mechanical dynamic model of the macro mechanism and micro mechanism are established, which is based on the rigid-flexible mixed dynamics of mechanical system. The dynamic characteristics of macro motion and micro motion are studied in detail, which is based on the mechanical dynamic simulation of Matlab. The accuracy of the established dynamic model and the performance of the stage are tested by using the scanning laser vibrometer. Both of the simulation results and test results show that the established model can well reflect the dynamic characteristics of the macro-micro composite positioning stage. It also indicates that the developed stage can well achieve a high acceleration and high precision motion, which aims to be applied in microelectronics manufacturing.

Abstract: In recent years, Fast Tool Servo (FTS) mechanism in precision manufacturing equipment emerges as a promising application for the piezo-actuated flexible nanopositioner. A flexible nanopositioner with large stroke, high bandwidth, high precision and multi-Degrees-of-Freedom (multi-DOFs) is really desired for this application. In order to meet this requirement, a novel 2-DOF flexible nanopositioner consists of two pairs of differential lever displacement amplifiers (DLDA) is proposed in this paper first, also, kinetostatics modeling is conducted by using the Pseudo-Rigid Body (PRB) method. After a series of mechanism optimal designs, the performance of the designed nanopositioner is verified by using the Finite Element Analysis (FEA) method. A piezoelectric (PZT) actuator with 90 µm is selected in this simulation, the experimental results indicate that the mechanism workspace can achieve around 2.1×2.1 mm², the bandwidth can reach up to around 136 Hz, while the cross-coupling is also kept with 1%. All the results consistently prove the proposed device possesses satisfactory performance for fulfilling the practical precision manufacturing tasks.

Abstract: Optical subsurface damage (SSD), generated from traditional grinding and polishing process, is prone to lower the laser-induced damage threshold (LIDT) of optical elements. Due to the fact that SSD elimination is on the premise of SSD evaluation, numerous SSD characterizing techniques have been proposed in the past few decades. In this paper, various SSD evaluations based on chemical etching technique are described and compared.

Abstract: Multiscale surfaces enriched with different scales of features are becoming widely used in many fields such as MEMS and optics industries. Due to the complexity of the multiple scale geometries, a single sensor or a single measurement can hardly obtain the holistic information of these surfaces. Multiple measurement method can solve this problem while it will introduce a lot of challenges for multiscale data fusion for the measurement results. This paper presents a framework of a data fusion algorithm for precision measurement of multiscale surfaces. The method makes use of iterative closest point based method to precisely register the datasets obtained in multiple measurements, and a Gaussian zero-order regression filter is used to separate the geometric features in different scales. Hence, the datasets are fused based on an edge intensity data fusion algorithm within the same wavelength. Finally, the fused datasets of different wavelengths were merged and replaced to the corresponding area in the large scale measurement to form a new surface with holistic multiscale information. The effectiveness of the proposed method has been verified on a v-grooved surface through a series of simulation experiments