Advanced Materials Research Vol. 426

Abstract: Based on multi-body dynamics theory, this paper uses ADAMS to carry on the dynamic simulation for assembly model of roller gear indexing cam mechanism in the case of frictionless and consideration of friction gap, detailed analysis of the gap generated by friction has influence on contact transmission of cam mechanism, and obtained the movement rule curves of angular velocity and angular acceleration and some valuable conclusions. It provided theoretical basis and reference for the subsequent design and research of roller gear indexing cam mechanism.

Abstract: A new high frequency induction brazed monolayer diamond wire saw for cutting aluminum alloy thick plate is developed with the helical continuous cutting edge distance on the wire surface. In order to solve the problems of forming cutting aluminum alloy plates,the brazed diamond wire saw is used to conduct the preliminary cutting tests on the 50 mm aluminum alloy plates on the modified grinder experimental platform.The results indicate that the cutting efficiency of the brazed diamond wire saw is increased with the increasing of the feed tension, the wire saw line speed and the diamond grits size. Furthermore, some cutting chips shape of the aluminum alloy is presented based on experimental cutting.

Abstract: Printed circuit board (PCB) composed of glass fiber reinforcement plastic and copper foil is a kind of typical composite material. The cutting process of fiber reinforcement plastic materials such as carbon fiber or glass fiber reinforcement plastic materials have been studied for many years, but the drilling process of printed circuit board using microdrill is more complicated than common carbon fiber reinforcement plastic materials. It is event that the cutting force changed when drill different material. The variation of drilling force may cause some problems such as drill break, board delamination. So it is important to study the drilling force in PCB drilling. The precision dy-namometer was used in experiments and cutting process was analyzed in this paper. The drilling process of PCB experience six stages and the drill will meet aluminum board, glass fiber reinforce-ment plastic (GFRP) and base strip. According to the drilling force in one circle, the peak force ap-peared at the moment of drilling copper foil and another smaller peak force appeared at the moment of drilling aluminum board and base board. The experiment results show that thrust force increased with federate and decreased with rotational speed.

Abstract: Fabrication technology of a novel miniaturized loop heat pipe, which consisted of an evaporator, a condenser, vapor and liquid lines, was present in this study. The evaporator, whose bottom was connected as the cycle channel of refrigerant, were consist of boiling and suction chambers to ensure the vapor to one-way flow to vapor line. Thin copper plates with micro-fins fabricated by the ploughing-extrusion (P-E) method were embedded in the boiling chamber as enhanced structures. Moreover, the copper fiber sintered felt fabricated by the solid-phase sintering of copper fibers with rough surface, was filled in the suction chamber of evaporator as the wick to provide the capillary force. In addition, the integral rhombic-shaped pillars as intensified condensation structures in the condenser were fabricated by the milling method.

Abstract: It is analyzed the error source on NC machining and the error caused by tool setting,tools-tip arc radius compensation and processing route.It is proposed to use the optical apparatus for tool setting, as far as possible to reduce the workpiece machining errors caused by the different high between cutting tool tip point and axis center. It is adoptted one-way slowly feeding and the clearance error of transmission system is eliminated, the positioning accuracy is ensured.

Abstract: In recent years, with the development of machinery industry, micro-cutting technologies have been gradually moving into engineering realization. The paper carries out a series of works on simulation modeling of micro-cutting of Ti-5Al-5V-5Mo-3Cr considering tool edge radius. Unlike conventional cutting, in micro-cutting the effect of tool edge radius which has a marked impact on cutting force, specific cutting energy, burr formation and burr size can no longer be neglected.

Abstract: In this paper the characteristics of geometric errors is discussed in detail, error compensation methods used in productive practice and relevant examples are given. Finally, the application of error compensation in different situation is discussed according to the characteristics of machining center. The machine accuracy can be improved by error compensation. It has important practical reference value for reasonable use and maintaining of NC machine tool.

Abstract: In order to control the 1~2-um protrusion height of mutilcore (MT) fiber endface in optic connectors, a micro grinding approach was developed using a 3D flock-structured film. The objective is to replace traditional lapping with loose-abrasive slurry. Experimental result shows that to achieve its height requirement and good quality, this approach requires 5-steps grinding processes with normal coated lapping film and three-dimensional coated flock lapping film. It is found that using 3-um-size silicon carbide flock lapping film, the grinding time and the pressure are the key factors to control he 1~2-um protrusion height of fiber endface. Moreover, the endface protrusion height of 1-um and larger can be achieved through the optimization of micro-grinding conditions.

Abstract: Model representation of workpiece in machining process simulation does directly influence on simulation accuracy and efficiency. The algorithm to acquire cutting width and cutting depth based on quadtree-array representation is discussed in this paper. In milling process simulation, workpiece is represented with quadtree-array and the cutting width and cutting depth are predicted real-time. The results of controlled simulation shows that the predicted cutting depth is accordance with that of the designed and the predicted cutting width is close to that of the designed within accuracy of half a discretization interval.

Abstract: Typically, eddy current sensor describes the distance by measuring the voltage reflected impedance of the coil. But in some cases, such as the measurement of different materials, the voltage (impedance Z) doesn’t change monotonously which may affect the sensor Measuring range and even the accuracy of the results. So we designed a new structure of eddy current sensor using phase sensitive detection techniques to analysis the impedance of the coil. After the A/D convention of C8051F020 MCU, the signal is analyzed and processed in PC,the displacement of the object is got. The experiment shows that the device has a high accuracy and stability, suitable for the tiny-distance measurement of different materials.