共查询到20条相似文献,搜索用时 171 毫秒
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提出了新型单牙轮-PDC钻扩联合钻头,先依靠单牙轮破岩钻孔,释放地应力,产生岩石损伤,再助推PDC钻头刮切破岩。运用有限元法,建立钻扩联合钻头、双级PDC和常规PDC钻头破岩的非线性动力学模型。通过对岩石本构关系进行D-P准则描述以及确定岩石破碎的判据,分析钻扩联合钻头钻进硬地层的破岩机理,开展了3种钻头动态破岩过程的对比研究。结果表明:钻扩联合钻头在钻进过程中井底井壁的岩石应力得到明显释放,大大提高了岩层可钻性;在硬地层中钻扩联合钻头钻进速度提高的主要原因是拉应力破岩;钻扩联合钻头在硬地层钻进过程中的扭转振动大大降低,破岩效率更高,钻头寿命更长;由于单牙轮领眼破碎岩石的作用,钻扩联合钻头对井底岩石的冲击破碎能力更强,在硬地层中钻进更快。研究结果为新型单牙轮-PDC钻扩联合钻头的研发提供了参考。 相似文献
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Eyup Bagci Babur Ozcelik 《The International Journal of Advanced Manufacturing Technology》2006,28(7-8):680-687
The drilling process is highly non-linear. Coupled with a thermo-mechanical machining, localized heating and temperature increases
in the workpiece are caused by the rapid plastic deformation of the workpiece and by the friction along the drill-chip interface.
The cutting temperature at the tool-chip interface is an important factor which directly affects workpiece surface integrity,
tool wear, and hole diameter and cylindricity in the drilling process. In this study, the effects of sequential dry drilling
operations on the drill bit temperature were investigated both experimentally and numerically. Drill temperatures were measured
by inserting standard thermocouples into the coolant (oil) hole of TiN/TiAlN-coated carbide drills. Experimental studies were
conducted using two different workpiece materials, AISI 1040 steel and Al 7075-T651. The drill bit temperature was predicted
using a numerical computation with Third Wave AdvantEdge finite element method (FEM) software, which is based on Lagrangian
explicit. The results obtained from the experimental study and finite element analyses (FEA) were compared. Reasonable agreement
between the measured and calculated drill bit temperature results were found for sequential dry drilling. 相似文献
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针对聚晶金刚石复合片(PDC)钻头在钻井破岩过程中因受力不平衡,导致钻井倾斜、井径扩大、钻头产生横向振动和涡动,造成钻头早期失效的问题,基于已有PDC钻头切削力学知识,构建了PDC钻头弯曲力矩及全局力平衡布齿优化设计模型,并提出模型求解方法。布齿设计实例结果表明,采用全局力平衡布齿设计方法得到的布齿结构可使PDC钻头在不同进尺条件下均能保持全局力平衡状态,尤其低进尺(小于1 mm)时的力平衡状态得到极大改善,提高了PDC钻头的钻井稳定性,对于改善钻头受力、提升钻头使用寿命、提高钻井质量与效率具有重要意义。 相似文献
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针对医用带线缝合针带线孔的加工难点,采用振动钻削,并研究设计了一种轴向振动钻削装置.试验结果表明,所设计的装置可以明显改善医用带线缝合针带线孔的加工质量,提高合格率. 相似文献
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Eyup Bagci Babur Ozcelik 《The International Journal of Advanced Manufacturing Technology》2006,29(7-8):629-636
In this work, effects of drilling parameters (drilling depth, feed rate, and spindle speed) on the twist drill bit temperature
and thrust force in the dry drilling of Al 7075-T651 material were experimentally investigated. During dry drilling experiments,
drill bit temperature and thrust forces were measured. Drill temperatures were measured by inserting standard thermocouples
through the coolant (oil) hole of TiN/TiAlN- coated carbide drills. The settings of drilling parameters were determined by
using the Taguchi experimental design method. An orthogonal array, the signal-to-noise (S/N) ratio, and the analysis of variance
(ANOVA) are employed to analyze the effect of drilling parameters. The objective was to establish a model using multiple regression
analysis between spindle speed, drilling depth, feed rate, and drilling method with the drill bit temperature and thrust force
in a Al 7075-T651 alloy material. The study shows that the Taguchi method is suitable to solve the problems with a minimum
number of trials as compared with a full factorial design . 相似文献
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定向喷嘴布置对PDC钻头井底流场影响研究 总被引:1,自引:0,他引:1
定向喷嘴布置的方式对PDC钻头的井底流场将有很大的影响,尤其是能改变PDC钻头的水力性能,因而研究定向喷嘴布置具有重要的意义.本文分析了喷嘴的不同布置方法,并通过数值方法模拟其对PDC钻头井底流场的影响.结果表明:在不完全对称布置方案的冲击区,在射流刚开始从喷嘴处流出去,但还未接触井底,各喷嘴射流处于衰减地带之内,这样的话将对钻头的清洗和携带岩屑离开井底非常有效果;在漩涡区,喷射角大、距钻头中心远的喷嘴射流则对清洗和携带井壁附近的岩屑起主要作用,喷射角小、距钻头中心近的喷嘴射流则对清洗和携带井底中心的岩屑起主要作用;在刀翼上的附面层由于周围喷嘴的影响,刀翼切削面低速区明显减少,剪应力增大,更好地预防、清除PDC钻头的泥包.最终达到提高机械钻速的效果. 相似文献
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Robotic-assisted internal fixation of hip fractures: a fluoroscopy-based intraoperative registration technique 总被引:6,自引:0,他引:6
Browbank I Bouazza-Marouf K Schnabler J 《Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine》2000,214(2):165-179
The internal fixation of proximal femoral (hip) fractures is the most frequently performed orthopaedic surgery procedure. When using a sliding compression hip screw, a commonly used fixation device, accurate positioning of the device within the femoral neck-head is achieved by initially drilling a pilot hole. A cannulated component of the hip screw is then inserted over the guide wire (surgical drill bit), which is used to drill the pilot hole. However, in practice, this fluoroscopically controlled drilling process is severely complicated by a depth perception problem and, as such, a surgeon can require several attempts to achieve a satisfactory guide wire placement. A prototype robotic-assisted orthopaedic surgery system has therefore been developed, with a view to achieving accurate right-first-time guide wire insertions. This paper describes the non-invasive digital X-ray photogrammetry-based registration technique which supports the proposed robotic-assisted drilling scenario. Results from preliminary laboratory (in vitro) trials employing this registration technique indicate that the cumulative error associated with the entire X-ray guided robotic system is within acceptable limits for the guide wire insertion process. 相似文献
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在难加工材料上利用超声波振动钻孔是一种十分有效的加工方法。应用超声波振动在非金属材料上钻削深孔,生产率可提高5~10倍,精度可提高2~3级,大大改善了加工表面质量;在耐腐蚀钢、耐热钢和钛合金以及其它难加工材料零件上钻孔、扩孔、铰孔、用丝锥切制螺纹及用滚子滚螺纹应用超声波振动是十分有效的加工方法;在深孔钻削铝合金时,应用超声波振动,高速钢钻头的耐用度可提高4~45倍。 相似文献
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Liping Tang Xiaohua Zhu Xudong Qian Changshuai Shi 《Journal of Mechanical Science and Technology》2017,31(10):4589-4597
The stick-slip phenomenon is a type of dysfunction detrimental to the drilling operation. Field application shows that stick-slip phenomenon is inclined to appear when using a large Weight on bit (WOB). In this paper, effects of the WOB on the stick-slip vibration are investigated. Based on a lumped torsional pendulum model of the drilling system, equation of motion of the drill bit is obtained. By using parameters commonly used in field applications, the bit dynamics are analyzed and the stick-slip vibrations are discussed. During the stick-slip motions, the negative damping effect occurs in the transition from the stick phase to the slip phase. With the increasing WOB, the bit behavior may change from the stable motion to the stick-slip vibration once the WOB reaches the critical value. In case of stick-slip vibration, the phase trajectory ultimately converges to a limit cycle which represents periodical bit motion. With increases in the WOB, the limit cycle enlarges. For cases without stick-slip vibrations, the drill bit vibrates damply and finally converges to a state of uniform motion. The results presented in this paper can be applied to interpret some of the field phenomena related to WOB. 相似文献
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基于PCB板业的发展现状,全面阐述了PCB板孔加工的基本情况,分析了国内外在PCB微机械加工的加工过程、钻削力与加工质量、钻头设计、钻头磨损与折断、机械钻孔孔位精度与机床动态性能等方面的研究现状。指出超微细孔其钻削加工尺寸属于介观尺度,多层PCB基材材料性能呈非线性且各向异性明显,钻刃磨损规律及刀具失效形式较为复杂,加工质量评价体系特殊等加工特点。提出目前亟待研究的关键理论问题包括PCB钻削去除机理、钻头失效机理、表面创成过程建模与质量控制、钻削系统工艺优化、钻头的优化设计与制造等方面。 相似文献
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Eyup Bagci Babur Ozcelik 《The International Journal of Advanced Manufacturing Technology》2007,34(9-10):867-877
In the past, many researchers have studied wear developed on drilling tools mainly due to the high temperatures generated which accelerate thermally related wear mechanisms and thereby reducing tool life. This paper deals with an experimental investigation on the effect of an internal coolant approach (for different air pressure) on drill bit temperature, comparing it with an external coolant approach and dry cutting. Drill temperatures were measured by inserting standard thermocouples through the coolant (oil) hole of TiN/TiAlN-coated carbide drills. Experimental studies have been conducted using Al 2014 alloy materials. In the drilling tests, cutting conditions had different spindle speeds, coolant approaches and feed rate values. The settings of drilling parameters were determined by using the Taguchi experimental design method. An orthogonal array, the signal-to-noise (S/N) ratio, and the analysis of variance (ANOVA) were employed to analyse the effect of coolant approaches and drilling parameters. The objective was to establish a model using multiple regression analysis between spindle speed, coolant (air) pressure and feed rate with the drill bit temperature. Mathematical models for drill bit temperature are proposed that agree well with the experiments. 相似文献
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S. R. Karnik V. N. Gaitonde 《The International Journal of Advanced Manufacturing Technology》2008,39(5-6):439-453
Burr size at the exit of the holes in drilling is a quality index and hence it becomes essential to predict the size of the burr formed in order to cater to the demand of product quality and functionability. In this paper, artificial neural network (ANN)-based models have been developed to study the effect of process parameters such as cutting speed, feed, drill diameter, point angle, and lip clearance angle on burr height and burr thickness during drilling of AISI 316L stainless steel. A multilayer feed-forward ANN; trained using error back-propagation training algorithm (EBPTA) has been employed for this purpose. The input-output patterns required for training are obtained from drilling experimentation planned through Box-Behnken design. The simulation results demonstrate the effectiveness of ANN models to analyze the effects of drilling process parameters on burr size. 相似文献
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During the drilling process, drill operators constantly adjust drilling parameters depending on a number of geo-tribological factors. The optimization of these parameters is typically based on trial-and-error field data from previous wells. As a step toward elucidating some of the underlying physics which affect the drilling process, the current work introduces a continuum-discrete approach which has the potential to predict rock wear rates. This model predicts how changes in rock strength, drilling fluid viscosity, drill bit angular velocity, and weight-on-bit affect the rate-of-penetration. Predictions from the model show qualitative agreement with experimental findings and field data. 相似文献
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AbstractHole-making is one of the most important processes of metal shaping domain. Although, drilling is a commonly used approach to cut holes in metallic parts, the process cannot be completed with the cutting action of one drill bit if the work material is hard and diameter of the hole is large. Usually, a drill having diameter equal to the required diameter of the hole is utilized to enlarge a predrilled hole of a smaller diameter. In this work, we have investigated sustainability of using another method of enlarging a pre-drilled hole, namely side and end milling and compared it with the drilling-based approach. The work material used in the study is a high carbon steel, which is heat-treated to two distinct levels of surface hardness. Besides process type and work material hardness, the other two parameters tested in the investigation are cutting speed and depth of hole. A total of 16 experiments were performed to generate data regarding the sustainability measures, namely hole surface roughness, specific cutting energy and tool wear. Process choice (drilling or milling) for hole-enlargement was found to possess a significant effect on all the measured responses. Analyses carried out on the experimental data revealed that although the drilling-based option led to an immensely better surface finish, the milling-based option performed better with respect to the other measures of economic and environmental sustainability. 相似文献