极细微钻开发的几个关键问题

伴随着电子信息技术的快速发展,印制板中HDI板、FPC板以及IC载板的比重不断增加,导通孔孔径越来越小,亟需高性能极细微钻的开发。论文首先分析了印制板微孔发展趋势,然后对极细微钻的材质特性和磨损失效机制进行了研究。重点讨论了极细微钻的关键参数包括螺旋角、第一后角和顶角的设计原则,介绍了极细微钻辅助设计的CAE法以及高速钻削的温度监测和影像监测方法,为极细微钻的优化设计提供指导。论述了极细微钻的涂层技术,对涂层微钻和普通微钻的钻孔能力进行了对比。最后给出了直径0.105mm微钻的开发实例,通过试验对其钻削性能进行了验证。     

超声微结构加工钻的研究

超声加工是一种新型的特种加工方法,它特别适合于不导电、硬脆和难熔的材料加工。该文利用了精确四端网络法和有限元相结合的方法,设计并制造出可用于微细孔和微三维结构加工的超声钻。通过实验测试的方法,对超声钻进行了测试,验证了有限元分析的结果。同时进行了钻孔实验,对超声钻的性能进行了评估。     

高厚径比微型钻头开发

随着印制板技术的发展,高厚径比孔的需求越来越大,常规槽长的微钻无法用于该类印制板的钻孔,亟需开发高性能的特殊槽长微钻,为高厚径比孔的加工提供解决方案。论文首先给出了高厚径比微钻的开发背景以及高厚径比微钻开发的关键问题。然后阐述了高厚径比条件下如何优化微钻设计来保障包括微钻的抗断钻、孔位精度和孔壁粗糙度在内的综合性能。最后给出了直径0.3mm、槽长直径比为24的微型钻头开发实例,并且通过试验进行了验证,结合钻孔试验介绍了高厚径比孔钻削的关键技术。     

印制板用微型钻头及微孔钻削进展

尽管激光钻孔在印制板（PCB）钻孔中应用得越来越广,但是利用微型钻头在机械钻机上进行的机械钻孔仍然是最重要的PCB钻孔方式。顺应PCB微孔的发展趋势,微型钻头直径越来越小,新型钻头结构不断出现,微钻头性能不断提高,微钻头涂层技术逐步成熟,微孔钻削的研究不断深入,推动着PCB技术的发展。本文即对微钻头及微孔钻削的进展进行总结,对微钻头和微孔钻削的趋势进行展望。     

基于神经网络的硅通孔电热瞬态优化方法

针对三维集成微系统中高密度集成导致的热效应和复杂的多物理场耦合问题,提出了一种基于神经网络辅助人工蜂群的硅通孔电热瞬态优化方法,用于高效准确地分析三维微系统中硅通孔阵列的瞬态电热问题.利用有限元分析软件进行了电热耦合协同仿真,分析了设计参数(硅通孔半径、氧化物厚度、硅通孔间距)对硅通孔阵列中铜柱温度、微凸点温度等性能的影响.利用神经网络建立了设计参数与性能参数之间的映射关系.提出了一种具有性能约束的协同优化策略,并采用蜂群优化算法对设计参数进行优化.根据优化后的设计参数,有限元模拟结果与预测性能基本一致,结构的最高温度误差为2.6%.结论不仅证明了优化策略的可行性,且与传统有限元方法相比,该优化设计方法极大地缩短了仿真时间,简化了多场耦合中复杂数学分析.     

如何提高多层印制板钻小孔的质量

在厚的多层印制板上钻小孔是困难的。本文着重论述如何提高在多层印制板上钻小孔质量几个关键方面问题。如:孔位误差的分析,钻头几何结构及性能要求,盖板和垫板材料的要求以及操作参数的运用。这些工作的研究和开展有利于提高多层印制板制造的质量和电子工业的发展。     

基于有限元法的微测辐射热计热电性能研究

采用有限元法针对微测辐射热计的热电耦合敏感机理进行研究.建立微测辐射热计精确三维有限元模型,采用动态热电有限元方法对器件的热电特性进行了分析,得到了其热电耦合场下的温度响应特性,并获取其热容、有效热时间常数和有效热导值等热学参数;采用该方法在微测辐射热计的设计阶段中,即可初步预判器件性能并为器件制备提供可靠的参考.所设计结构经流片验证,性能良好,且满足60 Hz帧频成像要求.     

基于高厚径比的5G通讯PCB微型钻针失效工艺研究

文章针对高厚径比的5G通讯PCB产品的微型钻针失效原因进行了系统分析,并输出了有效改善措施,实现了0.15 mm孔径、厚径比30:1的钻孔加工能力。基于钻针的受力分析,锁定了断钻的根因为排屑不良。通过对钻针三维结构进行数学建模,优化了钻针结构,提升了70%的排屑能力。工艺方面综合研究了钻机分步类型、预钻工艺对断钻的影响,并通过DOE锁定了最优钻孔参数。     

基于可靠性分析的PCB用微钻寿命优化浅析

浅析了运用可靠性分析对PCB用微钻寿命优化过程中的几个关键技术问题,以使PCB数控钻孔工序的成本最小化。在给出了微钻寿命优化框架的基础上,详细阐述了PCB钻孔不同质量控制参数对应的微钻可靠性分布规律和微钻寿命优化数学模型,指出了基于可靠性分析的PCB用微钻寿命优化的研发方向。     

挠性印制板拐角防撕裂结构信号传输性能分析

印制电路板的不连续问题已成为当今高速数字设计研究的重点．随着频率的增长和信号上升沿的变陡,挠性印制板拐角带来的阻抗不连续会引起信号的反射,严重影响系统的性能和信号完整性。由于挠性印制板很容易在大应力的作用下造成开裂或断裂,在设计时常在拐角处采用抗撕裂结构设计以更好的改善FPC的抗撕裂的性能。文章基于三维电磁场仿真软件HFSS,对挠性印制板多种圆弧拐角仿撕裂结构进行了研究．通过建立三维物理模型,分析了多种圆弧拐角防撕裂结构对高速电路的信号完整性的影响。     

微型钻头全自动数控精磨机结构设计及精度分析

文章介绍了用于微型钻头钻径精加工的全自动数控精磨机的工作原理和主要的结构设计,分析了影响机床加工精度的因素,提出了改善加工精度的措施,对于微钻加工设备的设计有重要参考价值。     

The detection of drill bit break-through for the enhancement of safety in mechatronic assisted orthopaedic drilling

The present surgical drilling processes, which are performed manually, can greatly benefit from mechatronic assistance. Measurement of bone drilling force can contribute significantly towards the enhancement of safety through the detection of drill bit break-through in order to prevent excessive protrusion of the drill bit. This paper describes a reliable and repeatable method of break-through detection based on a modified Kalman filter when drilling into long bones. A control strategy for the break-through detection is also provided. By applying the modified Kalman filter to force difference between successive samples (FDSS), the imminent drill bit break-through can be detected using different threshold levels of Kalman filtered FDSS (K-FDSS) in the presence of system compliance and inherent drilling force fluctuation. In addition, the method of break-through detection can be applied to different drill bit types over a range of drilling conditions.     

背钻孔内披锋改善分析研究

背钻技术在高频电路板上运用越来越广泛,但背钻技术在加工过程中出现孔内披锋频繁,严重影响产品信号传输,在下游的SMT厂家焊接过程中,容易出现焊接不牢、虚焊、短路等问题。文章主要针对背钻加工出现孔内披锋的研究,通过实验分析找出背钻孔内披锋产生的原因,并且有针对性的对加工参数、钻头选择等方面对背钻孔内披锋改善的影响度研究;发现加工参数和钻头选择为孔内披锋产生的重要原因,通过实验优化背钻加工工艺参数,能够明显改善背钻孔内披锋。     

Localization of drilling tool position through bone tissue identification during surgical drilling

This paper proposes a detection method to identify the drill bit position during assisted bone drilling. A platform has been developed to support the surgeon in the planning of the drilling path. Albeit constrained along a fixed trajectory, the advancement of the drilling tool is manual, in order to preserve the natural haptic perception of the surgeon, who remains in charge of modulating the drilling force and the feeding rate according to the position of the drill bit in the bone. This paper describes a custom drill, embedded with force and position sensors, which allows the evaluation of a new parameter, referred to as Average Impedance (AI), that is related to the mechanical properties of the tissues in contact with the drill bit. An algorithm for layer identification has been implemented based on the variability of the AI signal. In perspective, the AI can provide the surgeon with additional information about the position of the drill bit in the bone, in order to increase the safety level of the procedure. The algorithm has been tested ex-vivo on swine bones. The tests demonstrated a reliability better than 80% in the discrimination of bone tissues.     

基才滑模PI控制交流变频钻机旋转系统

钻井过程中钻头粘滑振动会导致钻头失速,钻杆组合故障,增加钻井成本。为此,提出了滑模PI控制策略用于电动钻机交流变频旋转系统。在建立钻机旋转系统模型基础上,将滑模控制与PI控制相结合,用于提高系统的鲁棒性．抑制钻头的粘滑振动。仿真结果表明：基于滑模PI控制的钻机交流变频旋转系统,可有效地控制钻头失速,减少钻柱疲劳损坏．改善旋转系统的动态和静态响应特性。     

Design Improvement of a Single-Phase Brushless Permanent Magnet Motor for Small Fan Appliances

In this paper, an adaptation of a shaded pole motor operating as a single-phase brushless PM motor is studied. After properly designing the rotor PM ring to avoid demagnetization problems, a nonlinear mathematical model for performance assessment and design improvement is proposed. The calculation of the model parameters is carried out by 2-D FEM analyses suitably corrected to also take into account 3-D effects, mainly due to different stator and rotor lengths. The procedure implemented in a numerical code makes it possible to investigate significant design aspects and determine the mechanical characteristic related to motor configurations adopted for small fan appliances.     

DRIBON: A mechatronic bone drilling tool

This paper presents a new automatic mechatronic tool for bone drilling, a procedure which is currently very manual and where depth control is critical in most scenarios. The system and methods developed involve driving a rotating drill bit in an axial direction so that both the linear movement and the rotation of the drill bit are controlled and measurable for automatic drilling procedures. Control algorithms allow the system to effectively stop the drilling procedure as a response to bone layer transitions and/or breakthroughs without damaging the surrounding tissue. Validation experiments on the new bone drilling methodology and proposed system have been carried out.