自动机床刀具的自动保护

介绍用单片机与逻辑控制电路自动测量和控制刀具的切削温度和切削力，从而保证刀具在切削加工中长久正常地工作，以达到提高刀具寿命、减少刀具消耗的目的。     

LIVE TOOLS数字微波系统在新闻直播中的应用

介绍了新闻直播的传输方式．LIVE TOOLS数字微波系统的构成和特点．微波系统在新闻直播上的实际应用，总结在安装调试中的经验和教训。     

Cyclic overaging heat treatment for ductility and weldability improvement of nickel based superalloys

Abstract

A new cyclic overaging heat treatment for ductility and weldability improvement of advanced nickel based superalloys has been investigated. The heat treatment consists of intermittent heating cycles during the cooling stage to check the nucleation of fine γ' in the material during the overaging. Using Rene 80 alloy as a model material, the effects of intermittent heating rate and duration were studied and optimised. Quantitative metallography was carried out to compare the microstructures produced by the proposed heat treatment with those produced by other conventional pre-weld heat treatments. Tensile tests and welding tests both showed that the proposed cyclic over-aging heat treatment is effective in improving the tensile ductility and weldability of Rene 80 alloy.     

MULTI-SCALE AND MULTI-PHASE NANOCOMPOSITE CERAMIC TOOLS AND CUTTING PERFORMANCE

An advanced ceramic cutting tool material Al2O3/TiC/TiN (LTN) is developed by incorporation and dispersion of micro-scale TiC particle and nano-scale TiN particle in alumina matrix. With the optimal dispersing and fabricating technology, this multi-scale and multi-phase nanocomposite ceramic tool material can get both higher flexural strength and fracture toughness than that of Al2O3/TiC (LT) ceramic tool material without nano-scale TiN particle, especially the fracture toughness can reach to 7.8 MPa·m0.5. The nano-scale TiN can lead to the grain fining effect and promote the sintering process to get a higher density. The coexisting transgranular and intergranular fracture mode induced by micro-scale TiC and nano-scale TiN, and the homogeneous and densified microstructure can result in a remarkable strengthening and toughening effect. The cutting performance and wear mechanisms of the advanced multi-scale and multi-phase nanocomposite ceramic cutting tool are researched.     

Meeting tribological challenges with surface engineered materials

Abstract

Tribological applications in the automotive, cutting tool and biomedical implant sectors continue to raise challenges for engineering materials. A brief review of these sectors indicates opportunities to improve surface durability through the application of innovative coating materials. Specific devices that might be improved in this way are engine piston rings, roller bearings, cams, cam followers, cutting tools and total joint replacements. This is the first time that the impact of thin hard coatings on tribological function has been assessed in three distinct engineering sectors.     

CURING PROCESS OF PHOTOPOLYMER RESIN BOND DIAMOND TOOLS

Analytical simulation and corresponding proof-test are adopted to study the principle of the curing process of photopolymer resin diamond tools. The influence of the diamond as abrasives in photopolymer resin owing to the absorptivity of the diamond for the UV light on the photopolymer resin curing process is discussed. Based on the above, a kind of diamond tool—dicing blade is selected to analyze the curing process of photopolymer bond diamond tools. An analytical model of curing process is developed and a correlation curve between the depth of polymerization of the photopolymer resin diamond tools and the exposure time to represent the curing process of photopolymer bond dicing blade. A test is done to proof-test the validity of the analytical model and the correlation curve. The simulated data fit the experimental results, which demonstrates the analytical models and numerical algorithm are of high reliability. The analytical simulation method could possibly be used to optimize the curing cycle and improve the quality of the photopolymers resin bond diamond tools.     

Stiffness analysis of hexaslide machine tools

This paper presents stiffness analysis of hexaslides, a class of parallel manipulators with six constant length legs, the base joints of which move along six distinct rail-axes. In the design of hexaslides for machine tool applications, stiffness as well as its variation within the workspace is important. The stiffness of any parallel kinematic machine and, thus, the accuracy depends on the pose of the tool platform. A stiffness model of a generic hexaslide is developed here considering the flexibilities in both the actuator and the legs of the hexaslide. The methodology adopted is based on the concept of the determination of stiffness of a group of serially connected linear springs. Based on the proposed model, the average stiffness and its variation along and about the Cartesian coordinate axes offered by three typical hexaslides, having the same foot print size, are estimated and compared. Other typical performance indices, i.e. workspace volume, workspace volume index (ratio of workspace volume to machine size), global dexterity index and global stiffness index, are also compared.