数控机床加工精度提高方法的分析

数控机床使用过程中存在很多产生加工误差的因素,而进给机构和编程误差对数控机床加工精度的影响都是可以通过改善而减小的,通过对这两方面的分析提出了相应提高机床加工精度的方法．     

非饱和滑带土非线性Burgers蠕变模型

基于非线性流变力学理论,建立了非饱和滑带土非线性Burgers蠕变模型。模型中不仅考虑滑带土非饱和特性-基质吸力对土蠕变特性的影响,同时考虑了与时间、应力状态有关的非线性黏滞体的流变特性,由非线性黏滞体替换Burgers模型中的线性黏滞体。对非饱和滑带土开展三轴蠕变试验,并对试验结果采用最小二乘法曲线拟合,获得了不同基质吸力下的蠕变参数,并将试验结果与Burgers模型拟合曲线以及提出的非线性Burgers模型拟合曲线进行对比。结果表明,采用非线性Burgers模型能很好地拟合试验结果,且与试验曲线的吻合程度、相关系数明显高于线性Burgers模型。     

模具零件叠加法快走丝电火花线切割加工研究

总结了影响叠加法快速电火花线切割加工的主要因素,通过正交试验法,对影响模具零件叠加法加工的电参数和非电参数进行了优化设计。试验表明,叠加法加工能有效提高模具零件加工效率,应采用尽可能高的峰值电流Ip、较高的脉冲宽度ON和适度的叠加厚度H及走丝速度V。     

方形阴极数控电解加工工艺试验研究

采用4种不同方案的方形阴极进行电解加工工艺试验,并对正交试验结果进行极差分析,得到工作电压、阴极进给速度、电解液压力、初始间隙对切削深度的关系曲线.通过比较4种不同方案阴极对切削深度的影响,得出最优的阴极结构.在此基础上,选取合适的工艺参数组合,进行方孔的电解加工试验.     

Analysis of hard turning process:thermal aspects

In manufacturing sector,hard turning has emerged as a vital machining process for cutting hardened steels.Besides many advantages of hard turning operations,one has to implement to achieve close tolerances in terms of surface finish,high product quality,reduced machining time,low operating cost and environmental friendly characteristics.In the study,three dimensional(3D) computer aided engineering(CAE) based simulation of hard turning by using commercial software DEFORM 3D has been compared to the experimental results of stresses,temperatures and tool forces in machining of AISI D3 and AISI H13 steel using mixed ceramic inserts(CC6050).In the following analysis,orthogonal cutting models are proposed,considering several processing parameters such as cutting speed,feed and depth of cut.An exhaustive friction modelling at the tool-work interface is carried out.Work material flow around the cutting edge is carefully modelled with adaptive re-meshing simulation capability of DEFORM 3D.The process simulations are performed at constant feed rate(0.075 mm/r) and cutting speed(155 m/min),and analysis is focused on stresses,forces and temperatures generated during the process of machining.Close agreement is observed between the CAE simulation and experimental values.     

Magnetic field-assisted photochemical machining (MFAPCM) of SS316L

In this paper, a new technique of photochemical machining (PCM) process has been described. The objective of this study is to investigate the effect of applying a magnetic field on the PCM of AISI 316?L stainless steel. The experiments were planned and conducted using a Full Factorial Design (FFD) approach. The control parameters selected were magnetic field, temperature, concentration and time. The analysis of the results shows significant improvement in the etch rate due to the application of a magnetic field. The highest etch rate was achieved at a concentration of 700?g/l, at the temperature of 60°C in a static magnetic field. The improvement of the etch rate is 2.5 times with the application of magnetic field as compared to the conventional PCM process.     

Optimization of process parameters affecting surface roughness in magnetic abrasive finishing process

Development in manufacturing technology enhances the mechanical behavior of machined parts and improves the surface finish with high precision, which conveys the progressive importance of magnetic abrasive finishing (MAF) process. In current research work, magnetic abrasive particles were used as finishing tools during the MAF process. However, these magnetic abrasives are fabricated by special techniques, i.e., the adhesive bonding-based method, the sintering method, the plasma-based method and so on. The present study explores the basic finishing characteristics of the magnetic abrasive produced by the sintering process. After the sintering process, improved quality of magnetic abrasives was obtained, where the abrasive particle sticks on the base metal matrix. The abrasive particle used is alumina powder and the magnetic particle is iron powder. Experiments were performed on Stainless Steel 202 to inspect the sound effects of several process parameters such as rotational speed, electromagnet voltage, machining gap and abrasive particle size on machining performance. Apart from that, surface roughness was also measured, which revealed the influence of the abrasive particle on the machined surface in terms of surface finish. It is observed from this study that appropriate size of magnetic abrasive particle optimizes the surface finish.     

基于CAXA制造工程师曲面加工方法的比较

对于曲面加工,CAXA制造工程师可以采用多种加工方法,这些方法所产生的加工表面质量及加工效率存在着一定的差异。文章以球的表面为例,对CAXA制造工程师2004中的几种加工方法进行测试,并用该软件的仿真功能进行仿真加工,对其效果进行了比较和研究。     

高速加工工具系统夹紧机构分析

介绍了高速加工工具系统的三种典型夹紧机构及其夹紧力放大效果。针对HSK高速加工工具系统的结构特点,详细分析了其夹紧机构的夹紧力。     

型腔类零件的数控加工

在普通铣削加工中,型腔类零件大都是使用成形刀具直接成形出来的。但是切削时刀具处于满刃状态、切削受力大、排屑差,零件的精度与表面粗糙度难以控制和达到要求。利用数控铣削加工此类零件均可通过走刀轨迹加工并能达到零件图要求。但在实际加工时(比如深槽加工、内腔转角圆弧小且内腔深度较大)都应在工艺上做相应的处理。通过对圆腔、方腔、带孤岛的腔体类零件的分析与数控加工可知加工工艺的确定非常重要。