基于宏程序的外球面粗精加工

目前,小内存的数控机床仍然是我国机床的主流,使加工程序变得简洁,对实际加工有着很重要的意义。宏程序的应用可以大大简化编程,本文通过实例介绍了数控铣削加工外球面的宏程序。     

Cf/SiC陶瓷基复合材料车削加工工艺研究

为满足高性能、轻质化的设计要求,开展了Cf/SiC基复合材料一金属连接工艺试验件的试验工作,阐述了Cf/SiC陶瓷基复合材料喷管车削加工难点和解决方案.理论分析和试验验证表明,通过选择合理的机械加工方法、人造金刚石聚晶车刀及冷却润滑方法,采用合适的切削用量和刀具几何参数,能够实现陶瓷基复合材料喷管连接部位的车削加工,保...     

精密薄壁支架零件高效防变形工艺研究

开展了精密薄壁支架零件的结构特点和技术难点分析,通过对薄壁支架类零件结构加工过程进行仿真分析、加工工艺优化等技术研究,实现了弱刚性结构零件的高效防变形加工,提高了弱刚性结构零件的加工精度和表面质量,从而满足了高精度薄壁支架类零件的质量要求。     

A critical evaluation of two Reissner–Mindlin type models for composite laminated plates

The purpose of this paper is to critically evaluate two Reissner–Mindlin type theories developed recently for composite laminated plates, namely, VAPAS (Variational Asymptotic Plate And Shell analysis) and EFSDT (Enhanced First-Order Shear-Deformation Theory). The fundamentals of both models are briefly summarized along with their unique features in comparison to most other existing models. The similarities and differences between VAPAS and EFSDT are also examined. Exact solutions of three-dimensional elasticity theory for the cylindrical bending problems are used as the arbiter to assess the accuracy of both models. Such a systematic assessment demonstrates that both models have achieved an excellent compromise between the layer-wise theories, which are accurate but computationally demanding, and the first-order shear deformation theories, which are computationally cheap but not accurate.     

金属塑变的全量理论与等效硬化曲线的关系研究

只要在加载过程中不卸载，就可证明全量理论与等效硬化曲线之间具有一定的依存性，在一定程度上可以互为前提和结果。而屈服准则，可以看成是全量理论或等效硬化曲线在一定的变形程度下的表达。     

热喷涂层的加工技术

热喷涂层由于其优异的高硬、耐磨、防腐等特性得到了广泛的应用,但如何优质、高效、低损耗地对其加工一直是困扰人们的难题。本文较为详细介绍了国内、外目前在热喷涂层加工方面的研究进展,存在的问题,各种加工方法的优缺点及适用范围。     

钎焊式离心轮加工工艺研究

离心轮水力性能的优劣对泵的效率影响最大，离心轮加工质量好坏直接影响泵的特性。针对钎焊式离心轮加工的技术要求与技术难点进行分析、研究，结合现有数控设备对离心轮的加工工艺进行改进、优化及数控加工转化。     

Corner-milling of Thin Walled Cavities on Aeronautical Components

This article presents a mathematical model of helical end-milling forces through experimental identification of the cutting coefficients and analyzes the changes of corner-milling forces under different conditions. In allusion to the corner-milling process, the relationship between working parameters and the corner coordinates is investigated by way of combination of tool tracing and cutting geometrodynamics. The milling parameters are optimized by changing the coordinates of tool center and working parameters without altering cutting forces. By applying the optimized parameters to milling practice, a comparison is made to show the improved product quality. Based on these optimized parameters, a finite element method (FEM) program is used to compute deformation values of a workpiece's corner, which evidences few effects that optimized parameters can exert on the corner deformation.     

EFFECT OF HEAT TREATMENT ON INTERMEDIATE TEMPERATURE STRESS RUPTURE PROPERTIES OF ALLOY K403

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HISTORICAL PROCEDURES AND G-DSG METHOD BASED MANUFACTURING PLANNING

Oriented to CAD/CAM seamless integration, this paper presents an idea for synthetically considering the qualitative history model, which represents the whole course of modeling, and the quantitative geometry model, which contains the extended Brep model, CSG and feature pedigree. History model building captures in background the dynamic interactive definition of engineering requirement and then explicitly conveys the original intention to successive application layers, which isc onductive to the decision support of manufacturing planning in not only automatic geometry re-constructing but also machining set-up. G-DSG theory as an earlier achievement is applied to generate the topology-independent generalized mid-model as an input to manufacturing planning, which istherefore simplified and its accuracy is simultaneously improved. Manufacturing planning lays emphasis on optimizing the mapping in both geometry and function from part itself to detail machining scheme. Comparatively, process planning pays more attention to the mapping to those items like tool, fixture, etc. Theoretically, such an idea is also beneficial to realizing the parametric NC machining trajectory generation and maintaining its dynamic consistency with the update of the design model.