Abstract: This paper presents a PMAC-based combined CNC machine that integrates technologies of ultrasonic machining, electrical discharge machining and high speed grinding. As a multifunctional machine, it can provide diverse machining methods for different materials. For hard and brittle materials, it can conduct ultrasonic machining and high-speed grinding respectively or in a combined form; for conductive hard and brittle materials, electrical discharge machining with or without ultrasonic vibration could be implemented. Driven by AC servomotors, the mechanical structure of
the vertical machine is mainly composed of a cross workbench for work piece handling, and a spindle head for tool feeding or high speed rotating. Besides those mentioned above, the system management program, the pulse power generator as well as the ultrasonic generator are also analyzed in this paper. Experimental results show that this machine has a wide range of application indeed and is suitable for various materials processing.
Abstract: The fracture is primary drawback to stability of production in the drawing of complex-shaped parts. In the paper, the fracture of complex-shaped part drawing is investigated experimentally and numerically. A grid method is adopted to analyze the deformation character, deformation path, deformation degree and safety margin in risk region where is determined by numerical simulation and experiment. The magnitude of safety margin and the stability of production are greatly increased by optimizing the height of draw-bead and the blank size.
Abstract: Research on precision forming laws of complicated blade has been a challenging issue on international frontiers of plastic forming areas. The precision forging laws of the blade with a damper platform have been obtained by using 3D FE simulation and physical modeling. The laws involve in the deforming characteristics of the tenon, damper platform, middle blade body, and tip blade body, such as the unevenness of deformation and material flow, the branch-flow of material, material flow characteristic of the blade body and rotation forming characteristic of the damper platform. The research may serve as a guide to the optimization design of relevant process and dies.
Abstract: Balance for high speed motorized spindle is most important, it will influence the dynamic behavior of the high speed machine tools. In this paper, the GD-IV high speed spindle is introduced. In order to improve its balance accuracy, the step interference fit is developed to connect the rotor and the shaft. The interference fitted assembly has been modeled theoretically, the analysis highlights that the tolerance of the interference fit consists of the static section and dynamic section, the static section is determined by the transmitting torque while the dynamic section is determined by the centrifugal force. The Calculation of interference fit for the GD-IV spindle shows that the dynamic section is about 4.5 times larger than the static. Furthermore, the three dimensional model of the step interference fit between the shaft and the rotor has also been built up with finite element method and the stress distribution on the mating surface has been calculated. The results show that the maximum stress occurring near the chamfer region of the internal surface of the rotor is up to 235 MPa lower than the permissible material stress 278 MPa, so that the design of the step interference fit is reliability and safety.
Abstract: The characteristics of fault diagnosis are as follows. First, features extraction is the key of improving diagnosis efficiency and correct rate. Secondly, fault diagnosis method based on rule reasoning has a wide application, but rule acquisition is one of the bottlenecks. Thirdly, rule modification is a key question of solving the real-time rule acquisition in the dynamic environments, and a primary question of knowledge base modification of expert system, etc. In this paper, Rough Set Theory (RST) was used to solve the key problems of machinery fault diagnosis, and a Rough Set
Data Analysis System (RSDAS) was developed. RSDAS was used to implement rule generation automation & rule modification based on RST such as indiscernibility relation and knowledge reduction method, depicted importance of different attributes in knowledge representation, and reduced knowledge representation space. The method of fault diagnosis using RSDAS was summarized. The experiment results approved the feasibility and the high precision of RSDAS. Therefore, we can use RADAS to machinery fault diagnosis.
Abstract: This paper uses HexaM made by Toyoda Machine Works Co. as an analytical model of parallel mechanism type machine tools. Much collision may be generated for its complicated structure and working space, using this machine. For example, those collisions are generated between the moving components of the parallel mechanism, between the moving components and a workpiece and between the moving components and the tool storage for automatic changing. In this paper, an
algorithm for detecting and avoiding those collisions is proposed. The method for avoiding the collisions is conducted by readjusting the location of the workpiece without amending the tool path. It is confirmed through experimental works that the proposed algorithm is useful for detecting the collisions and determining the location of the workpiece prior to the actual machining.
Abstract: Laser shock forming (LSF) is a new technique realized by applying a compressive shock wave generated by laser shocking on the surface of sheet metal. It is a mechanical, not a thermal process. After briefly reviewing the mechanism of LSF, instead of previously reported experimental research, a numerical simulation method of sheet deforming caused by laser shock waves is
presented. The process of laser-shock plastic deforming of sheet metal is simulated with ABAQUS software, the simulation results are compared and agree well with the experiments on the condition of single laser shocking. It is shown that numerical simulation is available for optimizing laser parameters and predicting the sheet deformation contour of laser shock forming process.
Abstract: This paper introduces a new hybrid model for tool condition monitoring (TCM) and
optimal tool management (OTM) in end milling operation. The model includes a wavelet fuzzy neural network with acoustic emission (AE) and a model of fuzzy classification of tool wear state with the detected cutting parameters supported by cutting database. The results estimated by cutting conditions and detected signals are fused by artificial neural network (ANN) so as to facilitate effective tool
replacement at a proper state or time. The validity and reliability of the method are verified by experimental results.
Abstract: A novel technique was developed for direct joining between ethylene propylene rubber and high ductile spheroidal-graphite cast iron using functional polymeric nanofilm without any adhesive. The functional polymeric nanofilm was created on the surface of cast iron by means of polymer plating with a synthesized organic compound of 6-diallylamino-1,3,5-triazine-2,4-dithiol monosodium salt. High peel strength joints of the rubber to polymer-plated cast iron were achieved by adding an accelerating agent of perhexane 3M under crosslinking condition of 418 K for 7 min. As the thickness of polymeric nanofilm was around 8.5 nm, peel strength of the joints was high to 8.9 kN/m and its broken-out section was rubber cohesive failure with 100% rubber coverage. Rubber/cast iron joints possessed good heat-resistant property. The film thickness and perhexane content had large effects on water resistance of joints. It is considered that high joining property results from chemical
bond at interface between polymer-plated cast iron and rubber chain.
Abstract: The kinds and the properties of composite materials and superhard cutting-tool materials are introduced in this paper. By using five kinds of superhard cutting tools, such as polycrystal cubic boron nitride (PCBN), polycrystal diamond (PCD), thin film and thick film of chemical vapor deposition (CVD) diamond and carbon nitride (CxNy), two kinds of composite materials (fiber reinforced and particle reinforced) have been turned. Many experiment data have been gotten. It is
shown that the superhard cutting tool is the best for machining composite materials. Moreover, surface finish and cutting force in composite material machining are discussed.