Key Engineering Materials Vol. 487

Abstract: This study was focused on the theoretical modeling and numerical investigation about the dynamic and static stiffness of spindle system of high speed grinder. The moment balance and the transition matrix, the state vector, field matrix of spindle system of high speed grinder were analyzed and deduced. The theoretical models about dynamic and static stiffness were established using the transfer matrix method. The numerical results showed that increas of the preload could result in the improvement of static stiffness of spindle end within the range of its working speed; the reduction of front overhang length would improve the stiffness of spindle end, as well as the dynamic stiffness of spindle at the working speed; the stiffness of spindle end decreased with the increase of speed with different bearing spans within the range of working speed of spindle.

Abstract: The paper presents a Web-based virtual machine tool system construction method. The key technologies required to build the system were analyzed. A simulation platform is built with ASP technology, and the geometric simulation is researched by using VRML, JavaScript, and JavaApplet. The physical simulation is researched by using Matlab Web Server, The object of the virtual machine tool simulation system is ultra-high speed grinding test bench. The developed system can realize virtual assembly, CNC code identification, material removal simulation, grinding force calculation and optimization.

Abstract: The manufacturing system developed in this paper is mainly used for the ultra-precision grinding of the hard-cutting materials, such as high strength steel and carbonized tungsten, which are characteristics with axisymmetric aspheric surface. Under the priority of accuracy and grinding rigidity to design the key components of multi-axis linked parallel grinding system of aspheric surface, such as high speed grinding spindle, B axis grinding rotary table, clamps and center high adjusting system. Maximum speed of the grinding spindle is 90,000rpm, spindle rotating accuracy is 0.1μm, rotation-angle-accuracy of B axis is , center height adjusting accuracy is 0.1μm, using the system can realize parallel grinding of aspheric surface[1].

Abstract: Due to having the features of high accuracy, high stiffness, high load capacity and longer service life, the hybrid bearing spindle system is widely used in grinding. This paper presents an analysis method of hybrid bearing spindle dynamic characteristics. The method uses CFD method to solve the oil film pressure field, instead of Reynolds equation, in order to obtain the oil film stiffness and damping. With the obtained oil film stiffness and damping to build the appropriate constraints, 3D finite element model of the hybrid bearing spindle system is established, and the modal analysis of the spindle system is carried out. Compared the analysis results with the theoretical calculation results, the feasibility and correction of the method are proved.

Abstract: This paper aims at structure strength analysis which makes the static and dynamic analysis for the numerical control abrasive belt grinding machine from key components to the whole machine and obtains relevant data and conclusions. On the base of the original structure, according to the design requirements, the important parts of the grinding machine are simplified and mechanical analysis. According to the calculated results and the constraints of the machine, the mathematical modeling of key components and the limit position can be obtained by using the mathematical theory of mechanical optimization. According to the results, the entity model and static analysis can be finished. Finally, the static and modal analysis of the large grinding equipment can be carried on the FEA software and draw some important conclusions.

Abstract: According to the example of using a common grinding and composition of parts processing movement and achievement elements, the design of construction of special NC technologies in ordinary grinding machine was formulated. . The grinding and polish-grinding were performed by using two NC systems in series to achieve multi-axis movement. The function and application scope of NC technology were expanded because the instantaneous compensation of the grinding wheel and the polish-grinding wheel were performed under a rectangular coordinate system and a polar coordinate system by using an open loop NC system. The application of surface recovery of grinding wheel by NC reconstruction and extension applications of processing the track of involute curve were referred.

Abstract: The alien stone turning-milling compound machining center（HTM50200）is the new generation multifunctional compound machining center. It is used to process rotating alien stone products and three-dimensional sculpture products. Pillar is the key support part of the machining center. The parallelism, straightness, levelness of the pillar affects the straight-line movement precision of beam parts. Therefore, the assembly precision debugging of the pillar plays the decisive role in the overall accuracy of this machining center. This paper introduces a kind of method by laser interference adjusting the assembly accuracy of the pillar. The results meet the design requirements of the assembly accuracy of pillar. It lays a solid foundation for the following-up assembly of the alien stone turning-milling compound machining center.

Abstract: China becomes the biggest producing country of synthetic diamond in the world. China’s output in 2010 is in excess of 7 billion carats. The yearly average increase rate is nearly 20% for the last 10 years. It almost accounts for 90% of the world’s production. China’s diamond is exported to 58 countries and regions in 2009. The yearly average export increase rate is about 30% for the last 10 years. Two main reasons supported such growth: 1) Continuous improvements made to the diamond synthesizing technology and as a result quality becoming better and better and to a large extend Chinese diamond is close to or equal to those made by her Western counterparts in terms of quality. 2) Competitive prices. The average price is only about $0.05 per carat in 2009, making it irresistible for world users to turn to Chinese diamond. Diamond producers in the Western countries turn to produce more profitable products like PCD & PCBN. This paper delivers some key statistics of Chinese diamond output and export in the last 10 years; it also highlights the diamond import in USA and Japan. The USA is the biggest consumer of China’s diamond. The supply & demand pattern for synthetic diamond is very much different from what it used to be 10 years ago. All these facts are further illustrated by the 10 figures and 1 table in this paper.