基于刚柔耦合的PCB钻床下钻机构的振动分析与研究

通过对PCB数控钻床下钻机构的钻孔误差进行分析,找出影响多层PCB板加工精度的主要原因,并对主轴系统下钻过程中的刚柔耦合动力学特性进行研究。充分考虑调心联轴器中的柔性调心轴和其他刚性构件的耦合,利用哈密尔顿原理和模态分析法建立下钻机构主轴系统的动力学方程。通过仿真求解得到了下钻机构钻孔过程中的电主轴部分的动态响应。结果表明：下钻机构主轴系统的安装误差、调心轴的刚度和支撑电主轴的空气轴承的阻尼对钻孔的偏心误差以及钻孔时的柔性振动有一定的影响。     

一种新型双系统数控深孔钻床的设计及分析

针对目前采油工程领域、航天航空工程领域以及核工程领域中,深孔零件的加工存在着加工方式比较单一、自动化程度低等问题,设计一种新型数控深孔钻床,能在一台数控深孔钻床上同时实现外排屑和内排屑,并且可根据工作条件来合理选择排屑系统。建立该机床的理论模型,介绍这种新型数控机床的工作原理,对机床的承重支柱进行有限元分析,并通过实际加工来验证其可行性,为深孔零件的加工提供了一种参考。     

深孔钻床的改造

应用可重构设计理论和先进的“DF“负压抽屑机理,对传统的深孔钻床进行了功能模块化设计和数控改造.同时实现了深孔刀具的系列化设计,极大地提高了深孔钻床的加工质量和应用范围.     

数控机床回转工作台动态性能分析与仿真

采用机械动力学原理建立数控机床回转工作台传动系统的数学模型,利用MATLAB软件的动态仿真工具箱Sim-ulink构造交流伺服电机驱动回转工作台传动系统的仿真模型,获得了反映数控回转工作台动态性能的时域和频域特性仿真曲线,通过仿真结果对系统的快速性和稳定性进行了分析,同时考虑齿轮以及蜗轮蜗杆传动间隙对传动精度的影响,给出了提高数控回转工作台动态性能的措施.为数控回转工作台进给伺服系统的设计、参数选择以及性能优化提供了理论依据.     

Z512钻床数控化改造

针对企业电路板等板件钻削加工特点,结合Z512钻床现有条件,确定了钻床的数控化改造方案,介绍了机械部分的改造设计、控制系统的硬件设计和软件设计.改造后的钻床提高了加工效率和加工精度,取得了较好的应用效果.     

微量润滑条件下BTA钻杆振动特性分析

研究了深孔加工微量润滑条件下,BTA钻杆的振动机理。结合理论分析,建立了钻杆振动有限元模型,利用ANSYA软件对微量润滑条件下深孔钻杆振动特性进行数值模拟。所得结论对BTA深孔加工的动态稳定性研究与深孔加工工艺的优化具有理论和实际意义。     

基于ADAMS的滚柱直线导轨副的动态仿真

针对于高速重载滚柱直线导轨副实际使用中存在的问题,以滚柱直线导轨结构设计和性能为分析重点,应用机械动力学理论、多体动力学理论及虚拟样机技术,在虚拟样机技术分析软件AD-AMS环境下对滚柱直线导轨副进行动态仿真研究,建立结构参数及性能与仿真输出结果联系,对结构参数进行优化设计,提高滚柱直线导轨设计效率及产品性能.     

复层气摸孔的电火花加工技术

介绍某高精度航空发动机燃烧室复层气膜孔的电火花加工技术。通过采用RD1－A型多电极数控电火花加工机床，优选EDM参数，有效地提高了气膜孔的加工质量和效率。     

深孔钻机床在模具加工中的应用

1.前言随着数控机床及加工中心等设备在我国的普及。模具加工高效率和高速化的发展过程中,对模具冷却水孔、顶杆孔进行深孔加工的数控深孔钻床也越来越引起人们的关注。占模具机加工工作量20～30％的钻孔加工设备,到目前为止大多仍采用摇臂钻机床。这就阻碍模具生产向大型化、高效率发展。下面就深孔钻机床的概况,加工特点和加工方法作一介绍。深孔钻机床如图所示。     

激光在高密度PCB制造中的应用研究

传统机械钻削难以满足高密度PCB微细孔的加工要求.试验表明,通过对激光波长模式、光斑直径和脉冲宽度等参数的精确控制,及利用激光束对材料相互作用的效应加工高密度PCB微孔,不仅能达到的较好加工质量,同时还体现出激光打孔快速、精准的优势.     

A study of dynamic stresses in micro-drills under high-speed machining

In this paper, a dynamic model of micro-drill-spindle system is developed using the Timoshenko beam element from the rotor dynamics to study dynamic stresses of micro-drills. The model includes effects of eccentricity of the spindle-clamp-drill system, the axial drilling force, the system rotational inertia, the gyroscopic moment, and bearings of micro-hole drilling machines on bending deformation of micro-drills during machining. After the model is verified using the published work, effects of the clamped length of micro-drills, the bearing stiffness and damping, the spindle speed, the system eccentricity, and the axial drilling force on dynamic stresses of micro-drills are analyzed using the model.     

基于多体动力学的折边机电机选型及实验验证北大核心

为保证数控折边机所用驱动电机能正常工作又不存在性能浪费,根据驱动轴的运动学、动力学特性,提出一种全面、准确、实用的电机选型方法。针对一款数控折边机,采用多体动力学仿真软件ADAMS建立其多体动力学模型。根据七段式S形加减速曲线,利用MATLAB对数控折边机的模尖进行运动规划,结合运动规划和ADAMS建立的多体动力学模型得到驱动轴的转速和负载扭矩。从峰值转速、扭矩、热平衡、惯量匹配及扭矩转速特性曲线四方面进行电机选型,并进行实验验证。结果表明:所提方法在保证折边机工作效率的同时能充分发挥电机性能。     

基于视频图形图象迭加的印刷线路板定位孔钻机

印刷线路板定位孔钻机中，钻头与ＰＣＢ定位靶中心位置的对准是决定系统加工精度的关键，传统的方法是通过人眼或光学系统中的分划板进行瞄准。本文介绍一种新的视频化ＰＣＢ定位孔钻机，以ＣＣＤ摄象机，单片机，ＣＲＴ控制芯片等组成视图形图象迭加电路。     

Identification and control for micro-drilling productivity enhancement

Micro-hole drilling (holes less than 0.5 mm in diameter with aspect ratios larger than 10) is gaining increased attention in a wide spectrum of precision production industries. Alternative methods such as EDM, laser drilling, etc. can sometimes replace mechanical micro-hole drilling, but are not acceptable in PCB manufacture because they yield inferior hole quality and accuracy. The major difficulties in micro-hole drilling are related to the wandering motions during the inlet stage, high aspect ratios, high temperature, etc. However, of all the difficulties, the most undesirable ones are the increases in drilling force and torque as the drill penetrates deeper into the hole. This is mainly caused by chip-related effects. Peck-drilling is thus widely used for deep hole drilling despite the fact that it leads to low productivity. Therefore, in this paper, a method for cutting force regulation is proposed to achieve continuous drilling. A proportional plus derivative (PD) and a sliding mode control algorithm will be implemented and compared for controlling the spindle rotational frequency. Experimental results will show that sliding mode control reduces the nominal torque and cutting force and their variations better than PD control, resulting in a number of advantages, such as an increase in drill life, fast stabilization of the wandering motion, and precise positioning of the holes.     

五轴数控机床综合空间误差的多体系统运动学建模

基于多体系统运动学理论的基本原理，结合RRTTT型五轴立式数控机床，阐述了多体系统的拓扑结构和低序体阵列，提出了特征矩阵的基本概念和构建方法，分析了多体系统有误差运动的基本规律，研究了根据特征矩阵得到综合空间误差的算法。理论分析和实例建模都显示所述方法能很好地解决误差建模的正确性、速度、通用性和自动化问题，为五轴数控机床精度分析和误差补偿提供了一种理想的误差建模技术。     

一种PCB型数控四轴钻铣床

PCB型数控四轴钻铣床是一种机电一体化产品,是专用于PCB加工的三轴联动数控机床.机床采用国际先进的直线滚动轨迹、高精度滚珠丝杆和交流伺服电机;涉及微电子、计算机、自动控制、精密机械、图像处理等多种技术,综合性强,知识、技术、资金密度高,适用于高精度PCB的成形加工.     

Model-based chatter stability prediction for high-speed spindles

The prediction of stable cutting regions is a critical requirement for high-speed milling operations. These predictions are generally made using frequency response measurements of the tool/holder/spindle set, obtained from a non-rotating spindle. However, significant changes in system dynamics occur during high-speed rotation. In this paper, a dynamic model of a high-speed spindle-bearing system is elaborated on the basis of rotor dynamics predictions, readjusted with respect to experimental modal identification. Variations in dynamic behaviour according to speed range are then investigated and determined with accuracy. Dedicated experiments are carried out in order to confirm model results. By integrating the proposed speed-dependant transfer function into the chatter vibration stability approach of Budak–Altintas [S. Tobias, W. Fishwick, Theory of regenerative machine tool chatter, The Engineer February (1958)] a dynamic stability lobes diagram is predicted. The proposed method enables a new stability lobes diagram to be established that takes into account the effect of spindle speed on dynamic behaviour. Significant variations are observed and allow the accurate prediction of cutting conditions. Finally, experiments are performed in order to validate chatter boundary predictions in practice. The proposed modelling approach can also be used to qualify a spindle design in a given machining process and can easily be extended to other types of spindle.     

基于ADAMS和MATLAB数控机床进给驱动系统的机电联合仿真

根据机械多刚体动力学理论建立数控机床进给驱动系统的数学模型,利用机械系统动力学分析软件ADAMS建立动力学模型、C++编写数控进给指令、MATLAB/Simulink建立数控机床进给驱动系统Simulink仿真模型,结合三者实现机床的机电联合仿真。仿真分析结果表明:该仿真平台能用来分析进给驱动伺服系统的动态特性,为物理样机进给系统的设计与调试提供可靠的参考依据。     

基于运动控制板卡的电路板钻孔机控制系统设计

钻孔是印制电路板(PCB)制造的关键工序之一。对于钻孔工序而言,影响孔壁质量的主要因素是钻头的转速和进给速度。介绍一种基于ADT850运动控制板卡的电路板钻孔机控制系统设计方案,着重介绍控制系统的硬件组成及基于VC++的软件构架。该系统采用光栅尺的检测信号作为反馈信号构成全闭环系统,提高了控制系统的加工精度。