手用通用型麻花钻

麻花钻用途广范,现有的各种先进修磨方法均有着较好的效果,但多适合于机用钻头,唯独适用于手电钻用的钻型不多。 1.手工钻孔的需求 手工钻孔指人工用手电钻对各种机件打孔,一般无机床夹具,工件只能用手工夹持。手工钻孔广范用于机械装配、建筑工地、施工现场、修理作     

新型无横刃深孔麻花钻的结构特点及刃形分析

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:     

改变麻花钻的刃面形状提高斜面钻孔精度

工件见图1,要在斜面上钻孔。我们设计了一套钻模见图2。加工过程中,虽然用了钻模,钻头刚开始与工件斜面接触时,钻床还是振动很大,切削速度慢,钻套磨损快,钻出的孔在上部尺寸精度和粗糙度都很不理想。     

麻花钻的CAD技术

本文介绍了用CAD进行麻花钻的设计方法,克服了用图解法设计时工作量大、精度低的缺点。文中着重研究了成形槽铣刀刃形的设计,其刃形是按相切接触条件严格计算出来的,并对刃形进行了分析和比较,提出了更正确地修正刃形的两种计算方法。     

麻花钻钻削加工过程的有限元分析

对WC硬质合金麻花钻加工45#钢工件上孔的过程,用Deform软件进行了有限元分析。研究了加工过程中刀具的轴向力和扭矩随切削时间的变化规律,得到了工件最大主应力的分布区域。分析了麻花钻加工过程中的温度变化,得到了刀具和工件温度云图。研究结果为麻花钻实际加工切削用量的选择提供了参考。     

麻花钻“S”型横刃的计算机辅助设计

数控技术的发展,数控机床和加工中心的普遍应用,对麻花钻提出了定心好耐用度高的要求,为此,我们对“S”型横刃进行了探索性的研究,建立了双曲面的数学模型,求解切削刃口任一点的法向后角,轴向后角和钻尖角、横刃斜角、横刃上任一点的前角和后角等一整套几何参数的数学模型。并对D=20mm麻花钻,用锥面与双曲面磨法,按正交设计进行切削试验,用正交回归进行数据处理,获得四个经验公式。“S”型横刃比锥磨麻花钻的轴向力平均下降24%,扭矩平均下降25%。从初步取得的效果看出,钻孔时的定心和耐用度将会得到改善。另外,还编制了一整套可行的运算程序。     

斜孔钻削工艺及麻花钻结构的改进

1　问题的提出我们在加工某军工产品的主要零件———定板(材料 4 5钢 ,外形尺寸ｌ0 0 5ｍｍ× 70 0 0ｍｍ× 2 0ｍｍ )时 ,共需钻削 10 71个2 4ｍｍ的 30°斜孔 ,且要求孔壁表面粗糙度达到Ｒａ6 3μｍ。钻孔加工时工件厚度大于名义尺寸 3ｍｍ(留作精刨余量 )。当在Ｚ35 5 0     

曲线刃麻花钻数学模型的研究

通过对圆锥面后刀面曲线刃麻花钻的结构进行分析,建立了其容屑槽、圆锥面后刀面、内刃前刀面和切削刃的数学模型,为刃磨参数的求解和三维参数化实体模型的建立提供了必要的理论基础。     

振动立钻上用麻花钻钻孔的研究

通过在新开发的振动立钻上钻孔的实验，证明轴向振动钻孔成功地解决了普通麻花钻钻孔中的断屑、排屑问题，并能降低钻削力，减少钻头磨损，延长钻头使用寿命，使钻孔精度及孔表面粗糙度明显改善。     

钻斜交叉孔用的四刃带麻花钻

一、设计与制造 四刃带麻花钻的设计与制造,如图1,除了在钻背上增加两条螺旋刃带外,其它与一般麻花钻完全相同,只需要选择一把厚度合适的,能保证前后两条刃带/的宽度的凹圆弧铣刀,铣出钻背?,留出四条螺旋刃带,再用45°铣刀铣出倒角就可以了。     

麻花钻后刀面建模方法的优化

在分析和研究麻花钻锥面刃磨法、变导程螺旋面刃磨法及螺旋锥面刃磨法的基础上,提出了横刃及圆柱螺旋线扫掠法,并构建了其数学模型。该方法预先设计横刃,以横刃及螺旋线复合扫掠的方法构建主后刀面。采用该方法得到了麻花钻直线主刀刃和理想的横刃及后角值分布;解决了采用变导程螺旋面刃磨法钻芯强度较弱以及采用锥面刃磨法存在的主后刀面"翘尾"现象;解决了两主后刀面磨削自然形成横刃形状的可控性。     

Investigating the feasibility of DLC-coated twist drills in deep-hole drilling

The ideal coating for twist drills used to drill deep holes should have both a high hardness and a smooth surface. The latter property is considered to ease chip evacuation through the drill’s chip flutes and, therefore, reduces the risk of chip clogging and possible premature drill fractures. For this reason, diamond-like carbon (DLC) appears to be a well-suited type of coating. This paper presents the results of cutting tests using DLC-coated HSS and cobalt-HSS twist drills when drilling deep holes of diameter 1.5 mm into plain carbon steel. Their capability to extract swarf from the borehole as well as their tool lives were investigated and compared to uncoated and TiN- and MoS₂-coated drills. Although the DLC-coated drills showed a very good swarf disposal capability, they did not exhibit a longer tool life when compared to off-the-shelf drills.     

Modeling of twist drills in terms of 3D angles

Traditional nomenclatures of specifying cutting tool geometries are two-dimensional (2D) in nature. The present work presents a paradigm to model the geometries of a variety of twist drills in terms of three-dimensional (3D) parameters. The work outlines the construction of a detailed computer-aided design (CAD) model for a fluted twist drill and establishes a new 3D definition for the geometry of drill in terms of biparametric surface patches. The flutes of the drill are modeled as helicoidal surfaces. For this, sectional geometry of tip-to-tip profile is developed and then swept. The geometric model of the shank is developed separately. The transitional surfaces are modeled as bicubic Bèzier surfaces. With this methodology, we propose a new 3D nomenclature for drill geometries in terms of 3D rotational angles. The relations necessary to map the proposed three-dimensional angles to two-dimensional conventional angles, known as forward mapping and their reverse relations (inverse mapping) are also developed. The new paradigm offers immense technological advantages in terms of numerous downstream applications.     

数控麻花钻磨槽机的设计

为提高加工效率和加工质量,对磨槽机进行数控改造和结构设计,并分析其工作加工过程以达到理想效果.     

Effects of different cooling conditions on twist drill temperature

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.     

麻花钻加工过程有限元仿真分析

通过有限元仿真Deform-3D软件,采用预先在CAD软件中画出的标准麻花钻实体模型,运用刚塑性有限元法及关键技术对麻花钻钻削机理进行研究,预测了加工工艺的部分结果和影响因素,为实际钻削加工过程参数的正确选择提供参考。     

Machinability of green titanium powder compacts during drilling using HSS twist drills

The poor machinability of titanium-based alloys has until now been addressed by either choosing a suitable tool material, management of the heat generated     

麻花钻钻削钼圆材料过程有限元分析

通过对标准麻花钻数学模型的研究,用Deform 3D建立了麻花钻钻削钼材料的有限元模型,并对钻削过程的应力应变、钻削温度和钻削轴向力的情况做了仿真研究。结果表明切削温度和轴向力都随麻花钻的转速及进给量的增加而增大,而选择合适的转速和进给量能使得材料的应变变小,切削形状良好。为钼材料的钻孔加工,工艺参数的选择提供了相关的理论依据。     

The effect of starting hole geometry on borehole quality and tool life of twist drills

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.