共查询到19条相似文献,搜索用时 156 毫秒
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东风汽车公司在加工深孔零件时过去大多采用普通麻花钻 ,在加工过程中时常发生加工质量不合格或钻头折断现象 ,造成零件报废 ,有时废品率可达3%以上。究其原因 ,主要是因为用普通麻花钻进行深孔钻削时存在以下不利因素 :①钻头细长 ,刚性差 ,加工时容易弯曲和振动 ,难以保证孔的直线度 ;②普通麻花钻的横刃为负前角 ,钻削时横刃处于挤刮状态 ,易引起钻头振动 ;③切屑长 ,且排屑通道长而窄 ,断屑、排屑困难 ;④切削液不易进入切削区 ,钻头易磨损 ;⑤钻头螺旋角和主切削刃前角较小 ,切削刃不锋利 ,排屑不畅。为提高深孔加工质量和加工效率 ,我… 相似文献
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在分析振动切削基本原理的基础上,采用了超声振动钻削的方法对金属基复合材料进行孔加工。借助自行研制的超声钻削设备,通过使用不同材质的硬质合金麻花钻,对两种不同含量的SiC颗粒增强铝基复合材料进行了普通钻削与超声振动钻削的对比试验。从复合材料的破碎形式、超声振动钻削力、钻头磨损以及孔的加工质量等4个方面对超声振动钻削复合材料的特性进行了研究。结果表明,轴向超声振动钻削能够提高入钻的定位精度及孔的表面质量,有效地改善钻头横刃的磨损,同时,钻削扭矩较普通钻削降低约30%。 相似文献
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麻花钻是实现孔加工的重要工具,然而切削刃口的快速磨损是制约钻孔质量和钻头寿命的重要因素。基于产品抽样钻孔试验与正交试验,本文对高速钢麻花钻的磨损、破损等失效形式进行了综合分析,探讨了以钻孔直径为评价指标时的孔加工数量与孔径的关系,并对麻花钻磨损的关键影响因素进行了正交试验研究。结果表明,麻花钻磨损与破损形式主要有主切削刃前刀面与后刀面磨损、横刃磨损、刃带磨损、外圆转角磨损、崩刃等;切削速度对麻花钻磨损影响最大、进给量次之、孔深影响最小;此外,随着加工孔数量的增加,孔径呈减小趋势。 相似文献
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<正> 本文介绍的麻花钻有两大优点:免除去毛刺的工序和具有自行定心的性能。还有钻削速度较高和寿命较长等优点。Gidding & Lewis-Bickford Machine 公司发展了一种综合螺旋钻尖和Racon 钻尖两者优点的新型钻尖。这种称作Bickford 钻尖的主要进步在于钻尖的工艺上。其主要优点包括:具有自行定心的性能和免除了去毛刺工序、也能采用较快的钻削速度和获得较长的刀具寿命。钻削问题金属切削工业中的大量因素导致发展了这种新型钻尖。这些因素包括:要求提高钻削生产率、延长刀具寿命、数控加工的广泛采用和提高现代化自动钻尖磨床的性能。由于螺旋钻尖和Racon 钻尖已能较好地满足上述要求,所以在许多钻削工序中已取代了普通钻尖。普通钻尖的直线横刃不能起到定心作用,因此常要求先使用中心钻。此外,普通钻头常常会在钻穿时产生毛刺。螺旋钻尖螺旋钻尖的S 形横刃起到修光和定心作用。此种钻尖钻出的孔径与钻头的直径极为接近,甚至常能免除或 相似文献
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研究不锈钢钻削过程中,螺旋角、后角、顶角及横刃对刀具磨损及切削热等现象的影响,分析不锈钢麻花钻的主要几何参数。通过对不锈钢麻花钻参数的优化,显著改善麻花钻切削状况,从而提高切削寿命;介绍了不锈钢麻花钻的参数优化、试验过程及结果。 相似文献
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本文所介绍的对称排屑槽麻花钻(图1)和不对称排屑槽麻花钻(图2)是西安石油学院孔加工课题组的两项专利。两种钻头都是用来钻削深孔的,前者可以有横刃,也可以无横刃,后者没有横刃。钻削轴向力小;容屑空间大;一般可以钻削(5~20)d_0(d_0为钻头直径)的深孔,一次钻通,中途不需退钻排屑,有四条棱带,导向良好,排屑顺畅,冷却液可通过冷却液输送槽进入切削刃部,冷却效果好,钻头经久耐用;钻孔质量良好。现将这两种钻头的结构特点及刃形介绍如下: 相似文献
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Xiangyu Wang Chuanzhen Huang Bin Zou Hanlian Liu Jun Wang 《The International Journal of Advanced Manufacturing Technology》2013,64(1-4):41-47
To investigate the influence of the geometric structure of coated cemented carbide twist drills on the drill tool life, drilling experiments of 42CrMo steel were carried out at various cutting parameters. The geometric structure parameters of the specially manufactured drill bits were designed by the multifactor orthogonal experiment method. The effects of cutting edge preparation, drill point geometry, and flute geometry on the tool wear were investigated by the range analysis and variance analysis. And their effects on chip pattern were also studied. Then the influence of cutting parameters on the tool life was investigated. Based on these investigations and extending the tool life, the optimized geometric structure was the honed cutting edge with a radius of 0.06 mm and conventional conical flank, and the corresponding cutting parameters were 80 m/min and 0.18 mm/rev. At last, the tool wear characteristics were discussed and the main wear mechanisms were abrasive wear, adhesive wear, coating exfoliation, and tipping. 相似文献
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R. Heinemann S. Hinduja G. Barrow 《The International Journal of Advanced Manufacturing Technology》2007,33(3-4):243-250
Detailed knowledge about the relation between wear progression of a cutting tool and the cutting forces generated is of paramount
importance for the development of a tool condition monitoring strategy. This paper discusses the changes in the different
process signals with progressing tool wear of small diameter twist drills (D=1.5 mm), when drilling boreholes having a depth
of 10 times the diameter in plain carbon steel using MQL. The effect of different wear patterns on the process signals is
presented. Furthermore, several features, which evolve over the life of the drills, are identified and extracted from the
process signals. Knowledge about the evolution of these features can support the user to determine the final tool life stage,
so that the drill can be replaced before the final fracture occurs. 相似文献
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用闭合场非平衡磁控溅射离子镀PVD涂层工艺在高速钢麻花钻上沉积了CrA lTiN梯度涂层。在干式切削条件下,对45#号钢和30CrMnS iA钢进行了钻削试验。通过涂层与未涂层钻头的寿命、磨损和切削力等试验比较,表明CrA lTiN梯度涂层钻头的切削性能远优于未涂层钻头,是一种极有发展前途的刀具涂层。 相似文献
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Improvement of Tool Life and Exit Burr using Variable Feeds when Drilling Stainless Steel with Coated Drills 总被引:4,自引:2,他引:2
T.R. Lin R.-F. Shyu 《The International Journal of Advanced Manufacturing Technology》2000,16(5):308-313
Variable feed machining is a signifant method for improving the cutting tool life and exit burr height for hard and difficult
to machine materials. Four coated drills were tested in the present study, namely, TiN, TiCN, CrN, and TiALN. The results
indicate that the amplitude of variation of feed, a = 0.6, is optimum for maximum tool life or minimum burr height. TiN-coated
drills were superior to CrN-coated or TiALN-coated drills when drilling stainless steel. The chisel wear and the outer corner
wear were the dominant mechanisms of the drill wear. 相似文献
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以原位生成晶须和颗粒混合增强钛基复合材料为车削对象,在切削速度为60~120m/min的条件下,对聚晶金刚石(PCD)和硬质合金刀具开展了车削性能试验研究。研究表明,PCD刀具的切削力为硬质合金刀具的77%~88%,其切削温度为硬质合金刀具的65%~82%。无论是高速切削,还是低速切削,PCD刀具都经历初期剧烈磨损而后稳定磨损的过程,而硬质合金刀具仅有急剧磨损的过程。刀具磨损特征方面,PCD刀具主要发生磨粒磨损和黏结磨损,硬质合金刀具主要发生月牙洼磨损、黏结磨损和扩散磨损。 相似文献
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Masato Okada Naoki Asakawa Yusuke Fujita Makoto Nikawa 《Journal of Mechanical Science and Technology》2014,28(5):1951-1959
In this study, the cutting characteristics of a drill reamer, which has conventional twist drill cutting edges appended for reaming, were investigated. A drill reamer has three types of cutting edges, whose roles are drilling, semi-finishing, and finishing. The cutting characteristics of a conventional twist drill were compared to those of the drill reamer. The cutting characteristics were evaluated using the thrust force, cutting torque, surface roughness, wear behavior of the cutting edges, and cutting edge temperature. The study used a workpiece made of carbon steel. The temperature of the cutting edge for reaming reached a maximum value of approximately 420°C, even though the depth of the cut was very small. The inner surface roughness with the drill reamer was superior to that with the conventional drill, even under dry and low-speed cutting conditions. The abrasive wear observed on the margin face of the cutting edge used for reaming. 相似文献
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Robert Karl Heinemann 《The International Journal of Advanced Manufacturing Technology》2012,60(5-8):519-526
This paper reports about the relationship between starting hole geometry and twist drill performance, which is determined by the location error and diameter of the drilled borehole as well as the tool life of the employed twist drills. The experimental results lead towards the conclusion that the type of starting hole has a significant effect on borehole quality. This, however, is not as commonly assumed attributed to a variation in the location error of the different starting holes themselves, but to how a starting hole allows the subsequent twist drill to engage in the cutting process. Although twist drills that drill straight into the workpiece material achieved the longest tool life due to a gentle engagement, a deep starting hole (‘pilot hole’) results in the most satisfying overall twist drill performance. 相似文献
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Three high speed steel grades, representing low, medium and high contents of alloying elements, were investigated in a comparative drill performance test using two different work materials. The results are discussed with reference to the observed wear mechanisms. Since drill performance is usually expressed as number of holes to failure, relationships between gradual wear and final failure of the drills are emphasized.The performance tests resulted in chisel edge, crater, flank and margin wear. The corresponding wear mechanisms were studied with the aid of scanning electron and light optical microscopy. The most important mechanisms are (1) abrasive wear for drilling in a plain carbon steel and (2) adhesive wear for drilling in a quenched and tempered steel. 相似文献