采用冷加工方法生产管端加厚钻杆的工艺探讨

本文提出的冷拔加厚钻杆两端的生产工艺优于目前的钻杆加工方法,采用此技术加工增厚钻杆具有等强度,性能均一,不易折断,可重复多次加工的优点。     

金刚石薄膜涂层钻头加工高硬度钢的实验研究

为提高金刚石薄膜涂层的韧性，避免金刚石薄膜涂层脆性断裂，以自贡硬质合金厂生产ZK-10型号硬质合金钻头为基体，采用厚度大约为3μmTiC作为过渡层，在表面涂覆4μm～5μm厚度的金刚石薄膜制成金刚石薄膜涂层钻头。用于加工硬度为HRC61的经热处理的GCrl5钢板，分别与未涂层硬质合金钻头、TiC-TiN涂层钻头对比，结果表明，金刚石薄膜涂层钻头由于加工速率高，摩擦发热量少，有效地避免了铁元素在高温下将金刚石转化石墨的作用，结果使用寿命比未涂层硬质合金钻头提高10倍以上，同TiC-TiN涂层钻头相比，初期加工性能明显优越，加工速率成倍数提高．但使用过程中，性能衰减更快，导致总体使用寿命同TiC-TiN涂层钻头相差不大。在表面喷砂处理中，金刚石薄膜涂层大部分易于脱落，剩余部分呈岛状分布，说明金刚石薄膜与基体的结合力分布很不均匀，这可能与金刚石薄膜的形核过程密切相关。     

Modeling of tool wear in drilling by statistical analysis and artificial neural network

The useful life of a cutting tool and its operating conditions largely control the economics of the machining operations. Hence, it is imperative that the condition of the cutting tool, particularly some indication as to when it requires changing, to be monitored. The drilling operation is frequently used as a preliminary step for many operations like boring, reaming and tapping, however, the operation itself is complex and demanding.

Back propagation neural networks were used for detection of drill wear. The neural network consisted of three layers input, hidden and output. Drill size, feed, spindle speed, torque, machining time and thrust force are given as inputs to the ANN and the flank wear was estimated. Drilling experiments with 8 mm drill size were performed by changing the cutting speed and feed at two different levels. The number of neurons in the hidden layer were selected from 1, 2, 3, …, 20. The learning rate was selected as 0.01 and no smoothing factor was used. The estimated values of tool wear were obtained by statistical analysis and by various neural network structures. Comparative analysis has been done between statistical analysis, neural network structures and the actual values of tool wear obtained by experimentation.     

波导法兰钻孔模优化设计研究

在雷达产品中,波导组件通过波导法兰盘端面的孔系进行定位连接,孔位置偏差大小直接影响波导组件装配后波导口之间的重合度。波导组件装配精度高,雷达传输系统的功率损耗小,产品电性能好。因此,优化波导法兰盘钻孔模的结构,提高法兰盘钻孔精度显得尤为重要。     

氧化时间对钛合金钻杆微弧氧化膜层结构和性能的影响

采用脉冲直流微弧氧化方法在钛合金钻杆表面制备了不同氧化时间下的TiO_2陶瓷膜层,用扫描电镜、X射线衍射仪、显微硬度计、球盘摩擦试验机及电化学工作站等分析了膜层的形貌、结构、组成以及膜层的硬度、摩擦磨损性能和耐蚀性。结果表明,随着氧化时间的延长,膜层的厚度增加,但膜层的硬度、耐磨性和耐腐蚀性先增加后降低。经不同氧化时间处理后,膜层的相结构主要由金红石型TiO_2和锐钛矿型TiO_2组成,此外还含有少量的Al2TiO5晶体和SiO_2非晶态。微观形貌分析表明,随着氧化时间延长,膜层表面粗糙度延长。在本实验条件下,当氧化时间为40min时,微弧氧化膜层的综合性能较好。     

基于自适应控制的数学学习系统的设计与实现

数学知识的学习过程是受教师、教材、环境和学生等内外多种因素影响的复杂系统。基于自适应学习和自适应控制理论,该文设计和实现了数学知识自适应学习系统。这对于实现数学知识学习的个性化和智能化,乃至学习效果的提高都有一定的理论和实践指导意义。     

金刚石绳索取心钻探工艺钻探深孔实际应用总结

主要介绍利用现有的能力较低的钻探设备，运用绳索取心钻探工艺钻进深孔的经验。     

Application of data fusion on multi-function earth drill

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Design of a Medical Non‐Linear Drilling Device: The Influence of Twist and Wear on the Fatigue Behaviour of NiTi Wires Subjected to Bending Rotation

This paper considers fundamental and experimental aspects associated with the engineering design of a medical, non‐linear drilling device which exploits shape memory pseudoelasticity of NiTi wires. For this application it is important that the NiTi wires have a good fatigue resistance. This is why the present authors have previously determined the influence of various parameters on cyclic life, crack growth and stress state of pseudoelastic wires subjected to bending rotation fatigue. The actual drilling device has to withstand twist in addition to bending rotation because the free rotation is constrained by friction between the drill head and the bone material. In addition, friction between the wire and a NiTi guiding tube results in wear and this may well promote fatigue crack nucleation. In this paper, we explain the function of the medical drill. We then report results on the effect of the additional parameters (1) twist and (2) wear on the fatigue life of thin pseudoelastic NiTi wires. We finally discuss the implications of our experimental results for the design process of the medical drilling device.     

Effect of tool wear on delamination in drilling composite materials

Among all machining operations, drilling using twist drill is the most frequently applied for secondary machining of composite materials owing to the need for structure joining. Delamination is mostly considered as the principal failure model in drilling of composite materials. Drill wear is a serious concern in hole-making industry, as it is necessary to prevent damage of cutting tools, machine tools and workpieces. The industrial experience shows the worn drill causes more delamination. This paper presents a comprehensive analysis of delamination caused by the drill wear for twist drill in drilling carbon fiber-reinforced composite materials. The critical thrust force at the onset of delamination for worn drill is predicted and compared with that of ideal drill. The experimental results demonstrate that though the critical thrust force is higher with increasing wear ratio, the delamination becomes more liable to occur because the actual thrust force increases to larger extent, as the thrust factor (Z) illustrates. Compared to sharp drill, the worn twist drill allows for lower feed rate below which the delamination damage can be avoided.