基于人工神经网络的滚挤压加工表面质量的预测研究

针对滚挤压工艺参数难于选取、已加工表面质量难以控制的问题，采用增加动量项和学习率自适应调整的BP神经网络建立了滚挤压加工表面质量的预测模型，并以表面粗糙度的预测作为实例进行研究，试验结果表明该模型可用于滚挤压加工表面质量的预测。     

铸造钢铁基表面复合材料的研究及其进展

阐述了铸造钢铁基表面复合材料的制备工艺和研究现状,并列举了典型制备工艺的优缺点及应用现状,评述了铸造钢铁基表面复合材料的基体材料和增强材料的选择原则,指出了铸造钢铁基表面复合材料今后研究的方向,并展望了其应用前景.     

颗粒增强金属基复合材料制备工艺的综述

概述了颗粒增强金属基复合材料的种类,介绍了目前颗粒增强金属基复合材料的常用的制备工艺.     

6061-T6铝合金纵-扭复合振动超声深滚加工试验研究

基于纵-扭复合振动超声加工和超声深滚加工提出了纵-扭复合振动超声深滚加工工艺。采用普通深滚与纵-扭复合振动超声深滚2种加工方法对供应态6061-T6铝合金轴件进行表面强化处理,研究深滚工艺参数对加工表面质量的影响。结果表明:引入纵-扭复合振动后,超声深滚工艺参数对表面质量的影响规律与普通深滚不同,且在相同的工艺参数下,超声深滚所获得的表面粗糙度Ra值要小于普通深滚,最高降低约50%,而表面显微硬度和硬化率则有大幅提高,硬化率最高约为普通深滚的3倍,经纵-扭复合振动超声深滚处理后的表面更光滑,从而证明了纵-扭复合振动超声深滚加工工艺能更有效地实现6061-T6铝合金的强化处理。     

我国颗粒增强钢基铸造复合材料研究的现状

回顾了颗粒增强钢基铸造复合材料在中国的研究发展概况，评述了颗粒增强钢基铸造复合材料的钢基体和增强颗粒的选择原则，较系统地介绍了外加增强颗粒和原位内生增强颗粒的工艺方法制备钢基复合材料。     

颗粒增强金属基复合材料的研究进展

概述颗粒增强金属基复合材料的成型工艺,介绍各种工艺的制备过程、在制备技术中存在的主要问题及解决措施,列举典型制备工艺的优点及应用范围,介绍国内相关的研究成果和应用状况,并对其今后发展的方向进行了探讨。颗粒增强金属基复合材料具有成本低、高强度、高模量、高耐磨性、易于制造等优点。指出颗粒增强钢铁基复合材料是当前研究的重要方向之一,颗粒增强钢铁基复合材料具有广阔的应用前景。     

颗粒增强镁基复合材料的制备工艺研究进展

综述了颗粒增强镁基复合材料的主要制备工艺和研究进展,重点介绍了粉末冶金法、搅拌铸造法和原位反应自生增强法等制备方法,并阐述了各种制备方法的特点和存在的问题。对颗粒增强镁基复合材料制备工艺的发展提出了自己的看法,指出半固态搅拌法是最适宜工业化生产的制备工艺,原位反应自生增强法是最具研究前景和发展潜力的制备工艺。     

硼纤维增强铝基复合材料的研究进展

从硼纤维的基本性质和制备工艺等方面,综述了硼纤维增强铝基复合材料的复合工艺和性能特点,并简述硼纤维增强铝基复合材料的发展应用方向.     

铁基表面复合材料的制备技术及研究进展

回顾了目前颗粒增强铁基表面复合材料的研究概况,介绍了基体材料和增强体材料的选择、主要的制备方法及目前存在的问题.将传统的铸造工艺或激光等与自蔓延技术结合是制备该类材料比较可行的工艺方向.     

基于纤维增强复合材料的超声振动辅助加工技术综述

纤维增强复合材料是一类使用范围不断扩大的具有优良机械性能的工程复合材料,但由于其具有各向异性及增强体纤维稳定的理化性能,使得传统金属加工方法很难对纤维增强复合材料进行高质量的加工,特别是对于以芳纶纤维等断裂伸长率较高的纤维为增强体的复合材料,存在较为严重的撕裂、毛刺和分层等加工缺陷。超声振动辅助加工是一种将超声振动附加在机械加工过程中的加工方式。超声振动的加入可使刀具与工件周期性接触,减小切削阻力,降低切削温度,可在一定程度上提高纤维增强复合材料加工的表面质量,减少加工缺陷。在介绍超声振动辅助技术的分类、系统组成和加工机理,及纤维复合材料表面质量、材料去除、加工机理和加工缺陷的基础上,从套料制孔、螺旋铣孔和轮廓铣削三类常见加工工艺方面,论述了针对纤维复合材料的超声振动辅助切削技术的国内外研究进展。基于纤维复合材料超声振动辅助切削技术的发展状况,从基础理论研究、材料表面改性和新加工工艺探索、超声振动加工系统的开发完善等方面,总结了现有研究和应用中的成果及普遍存在的问题,同时对未来研究的发展趋势做出了展望。     

径向基函数神经网络在复合材料滚压加工中的应用

文章以滚压速度、进给量、滚压力、滚压次数为输入参数,建立了对表面粗糙度进行预测的径向基函数神经网络模型,利用该模型对高硅铝合金基复合材料的已加工表面粗糙度进行了预测.结果表明,预测值可达到满意的精度要求,对7组样本进行预测时最大相对误差不超过12%,且表面粗糙度值越大,模型的预测效果越明显;模型的学习速度和精度均优于传统的BP神经网络.此外,利用所建立的模型对滚压工艺参数进行了优化,得出了工艺参数的最佳范围.     

Freeform surface finish of plastic injection mold by using ball-burnishing process

The objective of this study is to introduce the possible ball-burnishing surface finish process of a freeform surface plastic injection mold on a machining center. The design and manufacture of a burnishing tool was first accomplished in this study. The optimal plane ball-burnishing parameters were determined by utilizing the Taguchi’s orthogonal array method for plastic injection molding steel PDS5 on a machining center. Four burnishing parameters, namely the ball material, burnishing speed, burnishing force, and feed, were selected as the experimental factors of Taguchi’s design of experiment to determine the optimal burnishing parameters, which have the dominant influence on surface roughness. The optimal burnishing parameters were found out after conducting the experiments of the Taguchi’s L18 orthogonal table, analysis of variation (ANOVA), and the full factorial experiment. The optimal plane burnishing parameters for the plastic injection mold steel PDS5 were the combination of the tungsten carbide ball, the burnishing speed of 200 mm/min, the burnishing force of 300 N, and the feed of 40 μm. The surface roughness R_a of the specimen could be improved from about 1 to 0.07 μm by using the optimal burnishing parameters for plane burnishing. Applying the optimal burnishing parameters for plane burnishing to freeform surface plastic injection mold, the surface roughness R_a of freeform surface region on the tested plastic injection part could be improved from about 0.842 to 0.187 μm, through a comparison between using the fine milled and using the ball-burnished mold cavity.     

Effect of Ball Burnishing Process on the Surface Quality and Microstructure Properties of AISI 1010 Steel Plates

A newly developed ball burnishing tool was designed and tested for surface finishing of large flat surfaces in a shortest possible time. Optimization and analysis of the burnishing process were carried on AISI 1010 steel hot-rolled plates using the Taguchi technique and response surface methodology (RSM) to identify the effect of burnishing parameters (i.e., burnishing speed, burnishing force, and feed rate) on surface roughness, surface hardness, and microstructure of burnished surfaces. The optimal burnishing parameters were found after conducting the Taguchi’s L₂₅ matrix experiments and obtaining the response models for the surface roughness and the hardness. It was found that the burnishing force has the most influential effect on the surface roughness and hardness, followed by the burnishing speed, and least influence by the feed rate. In addition, microstructural examinations of the burnished surface indicate that burnishing force more than 400 N causes flaking of the burnished surfaces. The optimal burnishing parameters for the steel plates were a combination of a burnishing speed of 235 rpm, a burnishing force of 400 N, and a feed rate of 0.18 mm/rev. Using these parameters, the mean surface roughness has been improved from Ra = 2.48 to 1.75 μm, while the hardness increases from 59 to 65.5 HRB.     

An investigation into the surface characteristics of burnished cast AlCu alloys

Burnishing is considered as a surface finishing process. In this process the metallic surface of the workpiece undergoes plastic deformation by the pressing action of a hard and highly polished rotating burnishing ball or roller. In the present work an attempt was made to study the effects of different burnishing parameters (force, speed and feed) on surface roughness and hardness of cast AlCu alloys. The experiments were conducted with a simply designed ball burnishing tool. The results obtained show that an improvement in surface characteristics can be achieved by the application of this process on cast AlCu workpieces.     

Study on the inner surface finishing of aluminum alloy 2014 by ball burnishing process

Tubular parts are important in many industrial applications (e.g. joints, fitting, etc.). The internal surface quality plays an important role in the part performance. Internal surfaces of non-ferrous materials are difficult-to-finish due to many problems encountered in grinding which is optimum for ferrous metals. Internal burnishing process is believed to be more suitable since it eliminates sticking, wheel dulling and overheating. In the present study, aluminum alloy 2014 is selected as workpiece material, an 8 mm carbon chromium balls were used for the internal burnishing process.

Statistically based on experimental design (response surface methodology) using central composite second-order rotatable design was used to improve the experimentation design without loss of accuracy for results. Mathematical models are presented for predicting five different surface profile parameters caused by internal ball burnishing process parameters namely; burnishing speed, feed, depth of penetration, and number of passes.

The results show that from an initial roughness of about Ra 4 μm, the specimen could be finished to a roughness average of 0.14 μm. The burnishing speed, feed and number of passes have the most significant effect on all surface profile parameters studied in this work.     

A model of smoothing slide ball-burnishing and an analysis of the parameter interaction

The paper analyses a model of smoothing ball-burnishing which takes into account the mechanical properties of the workpiece, the geometry of the workpiece-tool contact area as well as the stereometry of the machined surface. It allows the determination of the dependence of the tip displacement of the machined surface asperities on the burnishing tool pressure. In the model-based research the effect of the particular parameters of the burnishing process on the tip displacement was defined. The optimum value of the displacement and the pressure it takes under various burnishing conditions were calculated. The analysis results were verified experimentally.     

Experimental techniques for studying the effects of milling roller-burnishing parameters on surface integrity

Roller-burnishing is used in place of other traditional methods to finish 6061-T6 aluminum alloy. How to select the burnishing parameters to improve surface integrity (reduce surface roughness, increase surface microhardness and produce compressive residual stress) is especially crucial. This paper presents an investigation of the effect of roller-burnishing upon surface roughness, surface microhardness and residual stress of 6061-T6 aluminum alloy. The residual stress distribution in the surface region that was burnished is determined using a deflection-etching technique. Mathematical models correlating three process parameters: burnishing speed, burnishing depth of penetration and number of passes, are established. A Group Method of Data Handling Technique, GMDH, is used. It is shown that low burnishing speeds and high depths of penetration produce much smoother surfaces, whereas a combination of high speed with high depth leads to rougher surfaces because of chatter. The optimum number of passes that produces a good surface finish was found to be 3 or 4. The maximum value of compressive residual stress decreases with an increase in burnishing speed. The maximum compressive residual stress increases with an increase in burnishing depth of penetration and/or number of passes.     

Relief making on bearing sleeve surface by eccentric burnishing

The article describes how to obtain regular depressions in hole surfaces by means of eccentric burnishing. The principle of the method was explained and the mathematical formulae showing the relations among the process parameters were derived. A formula enabling the choice of the rotational speed of the burnishing head with regard to the (required) machining trace coverage of the surface was given. The structure of a head used for eccentric burnishing of bearings sleeves was described. Experiments checking the possibility of making various reliefs confirmed the practical application of the head. The investigation of the extent of tribological wear of steel/steel and steel/bronze sliding contacts were carried out. It showed explicitly that the specimen with oil pockets obtained by eccentric burnishing show much less wear than diamond turned ones.     

Centreless burnishing and influence of its parameters on machining effects

The article presents the results of examining the centreless roller burnishing technology worked out by the authors. The structure and the construction details of a prototype device for the centreless burnishing of shafts were presented. The experiments were carried on using 41Cr4 steel workpieces. The effects of the workpiece hardness, the surface roughness before burnishing, the deformation multiplicity and the tool interference on the roughness and the geometric structure after burnishing were investigated. The significant influence of the above parameters was confirmed and described as a mathematical power model. It also showed a beneficial effect of centreless burnishing parameters on roughness and geometric structure of the surface.     

Microstructure and residual stresses in surface layer of simultaneously laser alloyed and burnished steel

The new hybrid method, which combines the laser alloying process with slide burnishing, was investigated and presented in the work. Both treatments were performed on the laser stage in one operation. The experiments were done on carbon steel alloyed with cobalt stellite. The alloying process was conducted with continuous laser CO₂, at different parameters. The single- and multiple-path processes were investigated.The microstructure, microhardness and residual stresses of surface layer after the laser alloying process and laser alloying combined with burnishing were presented. The results of the experimental studies have shown that the proposed new hybrid method allowed for the generation of compressive stresses in surface layer of the alloyed material. The structural analysis has proven that the burnishing process had caused deformation of grains in the 20–30 μm thick zone and increased microhardness of the surface zone material.The X–ray diffraction measurements of residual stresses in surface layer of the samples subjected to the alloying process and burnishing, both in cold and hot conditions, were performed. In the case of multiple-path laser alloying treatment the tensile stresses, approximately 500 MPa, were obtained at the surface. Multiple alloying combined with burnishing generated compressive stresses of about ?600 MPa at the surface, substantially improving the surface layer.