无键槽辊环轴向定位孔型加工工艺设计

传统的辊环孔型加工利用心轴整体定位,依靠键联结传递动力,文章设计采用轴向定位的装夹方式,成功地进行了无键槽辊环的孔型加工,满足了生产需要。     

双弹性套式心轴在薄壁套加工中的运用

在研究传统装夹方法的基础上,针对一批具有代表性的薄壁套,着重分析零件结构特征,在装夹定位薄弱的地方不断改进,设计了一种双弹性套式心轴夹具,利用夹具中长、短弹性胀套的内、外锥面弹性变形夹紧定位,实现了装夹加工时不损伤基准面,定位精度高.     

基于普通车床实现变速箱盖三孔加工的工艺研究

针对镗床加工变速箱盖三孔存在的问题和不足,通过改装设计工装夹具,装夹工件在利用车床花盘安装在普通车床上加工,获得简单实用、经济性强的加工效果,改进了镗床加工孔的不足.     

摇摆的数控铣床加工方案与成效

对液压泵零部件——摇摆进行数控铣削加工,由于受通用平口钳装夹空间应力的影响,摇摆在受力作用下弯曲变形,影响加工的质量。本案所设计的专用平口钳不但避免摇摆装夹时不受空间力的影响,且装夹安全可靠,并能达到零件的加工要求。     

硬质合金薄壁轧辊内孔磨削装夹方法的改进

由于硬质合金大型薄壁轧辊，磨削加工内孔时容易产生变形，一般的装夹方法和磨削方法难以达到精度要求。针对这种情况。设计专用装夹夹具，采取合理的加工工艺，选择合适的砂轮，合理地控制磨削用量，较好地保证设计要求，提高了产品质量。     

轴瓦专用夹具的设计与应用

文章对轴瓦加工的工艺进行了分析,并设计了一组专用的轴瓦加工夹具,采用“化整为零”的方法将各个表面分开加工。使用这种夹具,既解决了加工难和装夹难的问题,又可以提高生产效率。     

基于NX Nastran仿真分析的压铸件装夹改进

针对镂空结构件压铸框架粗加工精度差、返修率高的问题,采用NX Nastran仿真分析的方法模拟了装夹变形量、确定其装夹施力的工装设计问题,并提出了解决方案。对改进方案进行了NX Nastran仿真分析,模拟并试验验证了装夹变形量满足工艺及设计技术指标要求。对粗精加工分别设计了专用工装,通过模拟仿真和加工试验,粗加工精度达到工艺过程要求、精加工精度由技术指标要求的IT6级提高到IT5级。     

龙门镗铣中心加工连接架工艺及作业时间研究

采用普通镗铣设备加工工件时,很难达到一次装夹完成工件的全部加工,即使勉强实现,加工精度和效率也很难保证。通过对数控龙门镗铣中心加工连接架的工艺方法的研究,实现一次性装夹、利用数控程序联动完成全部孔面加工,既保证了工艺基准与设计基准、装配基准的统一,提高工件加工质量,又发挥机床、工装夹具、刀具的最大效能,减少多次装夹找正等辅助时间,从而提高生产效率。并且通过利用切削经验参数计算,获得作业时间的理论值,为制定工件的工时定额提供理论依据。这种方法对所有加工工件的数控工艺和作业时间的研究,均具有良好的借鉴作用。     

强磁选机齿板加工技术研究

本文通过对强磁选机齿板的加工研究,设计制作了加工齿板的特殊刀具。同时为提高齿板的加工效率,在工件的装夹及机床的选型上有了很大的突破,加工效率提高了近十倍,并确定了最佳的切削参数及定型工艺。     

预精轧机辊环的心轴设计

广钢高速线材生产轧制线上的辊环材质较硬，要求加工精度也很高，为了能达到加工要求，必须设计一条用于装夹辊环的心轴对辊环进行车削。本文就心轴的设计制造进行论述。     

The Effect of a Laser Beam on Chip Formation during Machining of Ti6Al4V Alloy

The effect of the laser beam on chip formation when machining Ti6Al4V alloy has been investigated at different cutting speeds and laser powers. The characteristics of the segmented chip produced by laser-assisted machining (LAM) in terms of the tooth depth and tooth spacing were strongly dependent on the cutting speed and laser power. Two types of segmented chip formation processes were observed, one at low and the other at high cutting speeds with a continuous chip occurring between these two types of segmented chips. The critical cutting speed at which the transition from the sharp, segmented chip to the continuous chip occurred increased with laser power. To obtain the continuous chip, plastic deformation at the shear zone to match the deformation strain introduced by the cutting tool is required. This can be achieved by laser heating the material in front of the cutting tool. A physical model is proposed to explain qualitatively the chip segmentation in conventional machining and the continuous chip transition at high cutting speed with the application of a laser beam.     

通过测量电力输入预测磨料/工件界面的条件变化

A monitoring system is proposed in order to detect the condition changes at abrasive/workpiece interface in abrasive cutoff operation.The system can detect the condition changes from the electric power change consumed by the driving motor of lapping tool.The electric power is strongly related with the abrasive effectiveness.When the abrasive effectiveness has been kept a normal state,the electric power also has been kept a constant value.The bodily removal of abrasive leads to reduce the electric power monotonously.The piling up of cutting chips leads to a peculiar electric power change;the electric power increased gradually at the beginning and then began to fluctuate periodically.The severe adhesion of cutting chips to the cutting edges leads to the loss of nominal function in the cutting edges and the electric power input was thus descended suddenly at an early stage of lapping.     

Experimental and Analytical Based Investigations on Machinability of High-Chrome White Cast Iron Using CBN Tools

High-chrome white cast iron (HCWCI) is one of the hardest metals used in the process and mining industries faces tough challenge in metal cutting. Focusing on this issue, influence of cutting parameters (e.g., cutting speed, depth of cut, feed rate) on machinability characteristics (e.g., cutting forces, surface roughness, material removal rate, machining power) of HCWCI has been investigated by experimentally and analytically using cubic boron nitride (CBN) cutting tools. Experimentation is carried out in conjunction with the Taguchi techniques and the influence of each cutting parameter of the process has been analyzed by analytical tools; analysis of variance, regression technique and artificial neural networks (ANNs). The study reveals depth of cut has the highest contribution on the cutting forces, and cutting speed on surface roughness and machining power. The confirmation test identifies both regression and ANN techniques are the most effective tools to evaluate machinability characteristics of HCWCI. Further, the CBN cutting tool exhibits excellent performance in machining of HCWCI.     

Machinability Investigations on High Chrome White Cast Iron Using Multi Coated Hard Carbide Tools

This study investigated the performance of multilayer hard coated carbide tool and multi-response optimization of the turning process for an optimal parametric combination to yield the minimum cutting forces and machining power with a maximum material removal rate (MRR) using Taguchi and artificial neural network (ANN) methods. In recent times, high chrome white cast iron finds increasing applications in aerospace, mining, mineral process industries. Its machinability using carbide insert (TiC/TiCN/Al₂O₃) cutting tool has been studied. The influences of cutting parameters on the cutting forces, MRR and machining power of the process have been analyzed using analysis of variance and the results are correlated using ANN. Linear regression method was used to establish the relation between the cutting parameters and the process responses. The confirmation test reveals that, the accuracy of prediction of ANN is better than that of the regression analysis. In view of the good performance of the carbide tools (at optimum conditions), it can replace the cosly CBN, with improved economic benefits.     

Properties of a Tool Produced by Powder Metallurgy

To minimize the manufacturing costs of parts with specified operational properties, the machining processes must be optimized. Cutting accounts for at least 70% of such processes. To that end, tool materials with distinctive properties may be developed and utilized. Analysis of manufacturing components—in particular, power components in gas-turbine engines—shows the need for higher quality of the machined surfaces and more efficient use of expensive equipment with numerical and adaptive control systems, so as to ensure a wide range of cutting conditions, including high-speed cutting. To obtain products that are domestically and internationally competitive, we need to optimize cutting processes, in which the tool is the weakest link in the technological chain. Defects of the cutting tool impair the productivity and product quality. In the present work, the wear of cutting tools produced by the sintering of high-speed steel powder is studied. Tool materials based on high-speed steel with additional alloying by titanium carbide (carbide steel) are shown to be highly wear-resistant. They may be classified as a new category of self-organizing tool materials. The results indicate the expediency of additional alloying by two methods to modify the tool friction and wear: (1) alloying with compounds that considerably reduce the self-organization by decreasing the frictional coefficient at working temperatures; (2) alloying to expand the range of self-organization. Both methods result in lower frictional forces and temperatures, as confirmed by the change in wear resistance and frictional characteristics. The wear resistance of such tools is found to be 2–3.5 times that of regular high-speed steel tools.     

浅谈高炉喷煤枪的车削加工

针对车削喷煤枪材料而出现的加工硬化倾向和切削力大、切屑粘附刃口严重、切削塑性变性大、切削热多等因素,经过对喷煤枪材料切削性能的分析,采用正确的刀具材料,通过多次切削实验,确定了车刀的几何参数和加工工艺,改善了原切削性能,提高了工件加工质量和效率,降低了刀具的消耗量.     

Development of Cutting Tool Through Superplastic Boronizing of Duplex Stainless Steel

In this study, a cutting tool is developed from duplex stainless steel (DSS) using the superplastic boronizing technique. The feasibility of the development process is studied, and the cutting performances of the cutting tool are evaluated and compared with commercially available carbide and high-speed steel (HSS) tools. The superplastically boronized (SPB) cutting tool yielded a dense boronized layer of 50.5 µm with a surface hardness of 3956 HV. A coefficient of friction value of 0.62 is obtained, which is lower than 1.02 and 0.8 of the carbide and HSS tools. When tested on an aluminum 6061 surface under dry condition, the SPB cutting tool is also able to produce turning finishing below 0.4 µm, beyond the travel distance of 3000 m, which is comparable to the carbide tool, but produces much better results than HSS tool. Through superplastic boronizing of DSS, it is possible to produce a high-quality metal-based cutting tool that is comparable to the conventional carbide tool.     

PCBN刀具高速精密切削W-Ni-Fe合金的性能研究

采用PCBN刀具对W-Ni-Fe合金进行高速精密切削试验,通过观测PCBN刀具前、后刀面的磨损形貌,分析了刀具的失效磨损机理;从CBN含量、刀具参数以及已加工表面粗糙度方面研究了PCBN刀具加工W-Ni-Fe合金的切削性能。结果表明,CBN含量高且刀尖圆弧半径大的PCBN刀具具有更长的使用寿命,在高速、低进给、小切深条件下可获得良好的表面质量。SEM和EDS分析结果表明,PCBN刀具高速精密切削W-Ni-Fe合金的磨损机理为粘结磨损、扩散磨损、局部剥落、氧化磨损以及崩刃磨损等多重磨损机理共同作用的结果。     

新型硬质合金微坑车刀切削能对比研究与预测

切削能绝大部分会转化为切削热,进而直接影响切削温度,因此研究切削能的产生、传递与转化对切削温度的研究尤显重要.本文以304不锈钢专用新型硬质合金微坑车刀创新设计为例,通过对新型微坑车刀和原车刀切削过程的切削能比较研究,建立车刀切削过程切削能与前刀面温度的关系模型,开展新型微坑车刀剪切能和摩擦能的预测研究和切削实验验证.研究结果表明,用实际生产推荐切削参数,干式切削情况下,新型硬质合金微坑车刀相比原车刀,输入能量降低8.96%,剪切能降低10.50%,摩擦能降低5.32%;刀具前刀面的切削温度与剪切能和摩擦能呈正相关关系;所建立切削能预测模型可为复杂切削条件下的切削能预测及前刀面切削温度研究提供参照.      

磁处理提升高速钢刀具切削性能的机理

利用自制的磁化装置对W6Mo5Cr4V2高速钢刀具进行磁化处理,并利用测量仪器分析对比不同磁化参数下高速钢刀具磨损以及工件加工质量的变化情况,并通过观察高速钢试样表面形貌和设计隔绝氧气切削和普通切削对比试验,探究刀具磁化后切削性能得到提升的机理。试验结果表明:磁化参数对磁化效果影响较大,且W6Mo5Cr4V2高速钢刀具最佳磁处理参数为30V、5 Hz、60s。磁场能促进微小磨屑的表面吸附,进而提高刀具的切削性能,且氧气的存在对工件表面粗糙度有一定的影响。磁化处理对高速钢残余奥氏体转变率的影响不是提高高速钢刀具耐磨性以及工件表面质量的主要原因。