钛合金法兰盘铣加工方法的研究

在钛合金法兰盘铣加工过程中,需要克服零件易变形、尺寸精度高、加工效率低、刀具消耗成本高等问题,该零件在控制成本和减小超差风险方面须进行研究,本文从该类零件的材料特性开始叙述了该零件加工过程中选择刀具的要点、走刀路径的设计和参数选择的过程,对如何提高钛合金零件加工效率、减小变形和降低超差可能性进行了分析,按照铣削方式对加工过程中切削负荷的控制方法进行了初步研究。     

环形刀具高速铣削走刀步长计算方法

为提高环形刀具高速铣削的效率,并且尽量降低设备运行的成本,通过考虑数控刀具加工弓高误差、刀具摆动误差、局部曲面几何形状以及数控刀具走刀方向等因素,并结合几种常用传统方法各自的优点,设计了走刀步长的计算方法。仿真实例表明,文中提出的走刀步长计算方法可以保证环形刀具高速铣削效率的同时,大幅降低铣削的费用。     

高速空气静压轴承的精密动平衡

圆弧刃天然金刚石刀具是加工各类复杂曲面零件的重要工具．在其刃磨过程中，机床主轴的端面跳动严重影响刀尖圆度和刃口半径，进而影响到加工表面的完整性．基于金刚石刀具研磨机床空气静压轴承的动平衡原理，通过现场动平衡实验，能够将主轴轴向振动的最大幅值控制在0．084μm以下，从而可以刃磨出满足超精密加工要求的高质量金刚石刀具．刃磨出的金刚石刀具刃口半径值可以达到0．05μm以下，7／尖圆弧圆度提高到0．2μm以内．     

新型滚光刀在数控车床上的推广应用

表面粗糙度是机械加工企业加工零件质量好坏的一个重要指标。尤其是表面粗糙度要求特别高的零件,必须在磨床上加工才能保证质量。这样不但增加生产成本,而且降低加工效率,直接影响到产品的进度,这是很多制造企业的一大心病。我们通过对问题的分析,采用普通车刀和滚光刀分别进行车削加工,检测零件的表面粗糙度,发现用滚光刀加工在零件表面粗糙度相对较高的情况下可以实现"以车代磨"的效果,提高了加工效率,挖掘滚光刀的优点并加以推广。     

刀具几何参数对Inconel 718切削力影响的仿真研究

Inconel 718是一种具有高硬度、高热强性和低导热性的难加工材料,切削加工中产生的较大切削力导致工件质量和刀具寿命的降低。由于刀具几何参数对切削力有很大的影响,因此通过仿真手段研究了Inconel 718斜角切削加工中前角、后角、钝圆半径、刃倾角和主偏角五个参数对切削力的影响,获得了刀具几何参数的最优方案,并建立了切削力的回归模型。结果表明,在给定的参数范围内,各因素对切削力影响的主次顺序为钝圆半径、前角、主偏角、后角和刃倾角;获得最小切削力的参数组合为前角5°、后角6°、钝圆半径0 mm、刃倾角10°、主偏角55°。     

浅谈专用成形刀具重磨技术

因零件特种曲面在加工中的特殊要求,需用成形刀具进行型面的粗加工、半精加工和精加工,本着降低制造成本的生产理念,而又要求生产出高精度、高品质的产品,在粗精加工时合理使用刀具后,依据刀具的使用情况分析刀具的磨损状况,运用成形刀具重磨技术对刀具进行修磨,既能保证产品质量又能降低制造成本。     

一种新型轴肩过渡曲线

本文提出用圆弧蜕变曲线作为轴肩过渡曲线，利用圆弧修整修出变曲率的砂轮曲线，以加工出切削轴肩过渡曲线的成型刀具的形状。采用最优化方法，寻求圆弧蜕变曲线的最佳参数，以降低轴肩应力集中．     

高频疲劳试样加工工艺的改进

针对目前螺纹结构圆截面高频疲劳试样加工繁琐、进给量小、加工效率低等问题,通过优化加工工艺、改进加工设备、优化螺纹连接底部过渡圆弧、增加抛光工序等措施对现有高频疲劳试样加工工艺进行了改进。结果表明:改进后的加工方法不仅提高了加工效率,提高了试验成功率,控制了加工成本,同时还提高了试验结果的准确性。     

基于工件形状特殊且存在大倒角及大过渡圆弧的加工

阐述了形状不规则的(不能在车床加工的工件)且存在大倒角孔或过渡圆弧的工件在SIEMENS840D数控落地镗铣床上的加工,利用SIEMENS840D系统中的R参数的功能,编写大倒角和大过渡圆弧加工程序时的加工思路、刀具的选择、数控程序的编制以及应注意的问题,该程序的加工使用既可以获得正确的R圆弧轮廓形状和尺寸,又能极大的提高加工生产效率。     

干式螺杆真空泵转子成型加工及其刃形计算

干式螺杆真空泵转子的快速、高精度加工是提升整机性能与降低生产成本的关键技术.本文基于一种附加刀具垂直位置与倾角调节的螺杆转子成型机床结构,采用接触线法建立其刀具刃形求解的数学模型,分析转子初始转角、刃形求解范围参数、刀具中心距、斜角与倾角对刃形的影响规律.结果表明:过大的刀具斜角会导致刃形的凹面结构,而过小的斜角使得刃...     

工装辅助加工隔膜泵导板

导板在隔膜泵的各部零件中,属于易磨损件,备件需求量大,因此我公司经常生产此产品。并且其加工周期长,工序多,在加工中占用大镗大量时间,我公司大镗属于重点设备,其承担着加工公司大量大型产品的任务,本文通过研究设计工装,实现在其他设备（龙门铣）上加工导板,以缓解大镗的生产压力,进而提高导板的生产效率及降低生产成本。     

Diamond and cBN hybrid and nanomodified cutting tools with enhanced performance: Development,testing and modelling

The potential of enhancement of superhard steel and cast iron cutting tool performance on the basis of microstuctural modifications of the tool materials is studied. Hybrid machining tools with mixed diamond and cBN grains, as well as machining tool with composite nanomodified metallic binder are developed, and tested experimentally and numerically. It is demonstrated that both combination of diamond and cBN (hybrid structure) and nanomodification of metallic binder (with hexagonal boron nitride/hBN platelets) lead to sufficient improvement of the cast iron machining performance. The superhard tools with 25% of diamond replaced by cBN grains demonstrate 20% increased performance as compared with pure diamond machining tools, and more than two times higher performance as compared with pure cBN tools. Further, cast iron machining efficiency of the wheels modified by hBN particles was 80% more efficient compared to the tool with the original binder. Computational model of hybrid superhard tools is developed, and applied to the analysis of structure-performance relationships of the tools.     

微小型齿轮片连续冲、修工艺

目的以冲压代替机加,提高零件加工的良品率和加工效率。方法用模具进行连续冲、修加工。结果生产效率提高1倍,零件加工良品率提高20%,生产成本下降25%。结论用模具进行连续冲、修可以代替机加铣齿加工,为微小型齿轮片的加工开辟了一条新的途径。     

304不锈钢管滚压成形圆锥外螺纹组织及性能研究

滚压加工螺纹可以获得更高的螺纹强度、精度,其在加工效率和环保性方面的优越性不容忽视.同时,滚压加工可以解决某些工艺方法不能解决的问题,如对特大型缸体的加工,可以达到减少机床和夹具、提高工件加工精度、缩短加工周期和节约作业面积的效果.为此,本文采用一种四滚丝轮车床滚压加工得到了304不锈钢管圆锥外螺纹.通过金相分析、扫描电镜、显微硬度计和万能试验机等手段,研究了304不锈钢管滚压成形圆锥外螺纹的组织及性能,并与传统的套丝管螺纹进行对比.研究结果表明,套丝加工的管螺纹,齿表层出现孔洞、金属组织被切断,其内部显微组织仍是原有的等轴晶,齿形不完整;而滚压加工使得螺纹表层组织细化,形成了沿螺纹齿形连续分布的纤维组织.套丝加工后304钢管螺纹硬度有所提高,但幅度不大;与套丝加工相比,滚压加工后304钢管螺纹的抗剪拉力和硬度均有大幅提高.     

聚焦离子束加工单晶体金刚石刀具实验研究

作为超精密切削加工刀具的理想材料,单晶体金刚石材料的加工制造方法直接决定了刀具切削加工表面的精度和质量.由于金刚石材料具有明显的各向异性,在传统的金刚石刀具机械刃磨法中需要综合考虑制备工艺和刀具性能的协同关系,主要包括不同晶面表现出显著的物理机械性能差异、不同晶向存在显著的难磨和易磨方向等.本文针对聚焦离子束(FIB)技术加工金刚石刀具的过程中,金刚石材料性质对聚焦离子束加工质量、加工效率的影响规律等关键工艺开展了研究.研究发现,与传统的机械刃磨法相比,聚焦离子束加工是基于高能离子束的轰击溅射实现材料的去除,聚焦离子束加工中存在的级联碰撞现象显著弱化了金刚石材料各向异性的影响.     

Effects of geometric angle and cutting speed on cutting forces and tool wear of ceramic cutting tools during peripheral up-milling of high-density fiberboard

In this paper, cutting forces and tool wear of ceramic cutting tools are investigated by up-milling high-density fiberboard under different geometric angles and cutting speeds. The results show that tangential force (F_t) and normal force (F_r) decrease with the increase of rake angle. The values of F_t and F_r at the higher speed cutting condition are lower than that at the lower speed condition. The flank wear (VB) declines with increased clearance angle and decreased cutting speed. The tool wear patterns observed on the ceramic cutting tools are pull-out of grain, cracking, tipping, and flanking. Abrasive wear and adhesive wear are the main mechanisms of the ceramic cutting tools. In all, on the premise of guaranteeing the ceramic cutting tools’ strength, the ceramic cutting tool with a bigger rake angle and clearance angle is advisable in high-density fiberboard machining, in terms of lowering the energy consumption and production cost required for machining.     

High-temperature properties and microstructural stability of hot-work tool steels

Indexable insert tools for machining operations are in service exposed to high temperatures and cyclic mechanical loads. Secondary hardening steels such as hot-work steels are commonly used for tools subjected to thermal exposure. However, these steels, highly alloyed with strong carbide forming elements as Cr, V and Mo, are generally difficult to machine and machining represents a large fraction of the production cost of a tool. Thus, the present study concerns the development of a new steel with improved machinability and meeting the requirements for high-temperature properties.Softening resistance of the THG2000 and QRO90 tool steels, commonly used in hot-work applications, and a newly developed tool steel MCG2006 with lower alloying content of carbide forming elements, was investigated by tempering and isothermal fatigue testing. Mechanisms of high-temperature softening of the tested tool steels were discussed with respect to their microstructure and high-temperature mechanical properties. Carbide morphology and precipitation as well as dislocation structure were determined using transmission electron microscopy and X-ray line broadening analysis.No difference in softening behaviour was found among the QRO90 and MCG2006 regarding hot hardness measurements. The THG2000 indicated some stabilization of the hardness between 450 and 550 °C and a considerable hardness decrease at higher temperatures.The short-time cyclic softening in isothermal fatigue was controlled by dislocation rearrangement and annihilation. The alloying composition of the steels presently tested had no influence on the dislocation density decrease.The long-time softening was affected by the material's temper resistance and strongly depended on the carbide morphology and their over-ageing resistance. The QRO90 with greater molybdenum and lower chromium contents than in the THG2000 show the best resistance to softening among the tested grades at all temperatures. The MCG2006, leaner alloyed with the carbide forming elements and alloyed with 4 wt% nickel, has better temper resistance than THG2000 at higher temperatures and longer tempering times.     

新桥矿爆破工艺与参数优化

为解决新桥矿大块率高、炸药单耗高及爆破效率低等问题,在对爆破工艺改进的基础上设计有限的爆破试验(13组试验)获取样本,并建立BP神经网络预测模型(隐含层节点数取9),以最小抵抗线W、孔间距a、周边孔距Z作为输入因子,以炸药单耗、大块率作为输出因子预测、优选爆破参数.优化推荐W=0.8 m、a=1 m、Z=0.8 m,对应的炸药单耗为0.2001 kg/t,仅为原工艺的50%;大块率为5.2091%,仅为原工艺的20%;生产效率提高了约65%.该方法采用有限的试验与智能预测相结合,实现低成本获取真实样本,并提高了预测精度.     

大型结构件数控加工在位计量检测技术研究

在位计量检测以加工机床为硬件载体,实现加工、测量一体化,对提高产品质量和生产效率有重要意义。介绍了数控加工在位计量检测系统的组成与方案的实现过程,对系统的性能进行了现场试验,结果表明大型结构件数控加工在位计量检测系统可对大型数控加工零件工艺过程中的尺寸和形位误差进行准确在位测量,大大缩短了大型数控加工件的定位时间,有效提高了一次装夹加工的效率和合格率,避免了工件的二次装夹,降低了生产成本,为数字化装配提供有力保证。