挤压丝锥在铸铝件上的应用

挤压丝锥是一种先进的无切削螺纹孔加工刀具,适用于塑性材料的螺纹孔加工。它同普通丝锥相比,在刀具寿命、加工精度、表面粗糙度、工效以及提高螺纹强度等方面,具有显著的优点。由于它攻丝后不产生切屑,即使是小盲孔螺纹也极易清洗干净,这对于清洁度要求较高的液压元件来说特别有利。为了在加工CB齿轮泵体上使用这种丝锥,事前进行了必要的工艺试验,得出了比较适宜的工艺参数和切削液选择,现将基本情况介绍于下。     

钛合金小直径螺纹攻丝研究

一般情况下,钛合金小直径螺纹的攻丝加工较困难,且效率低。应用对比试验分析,从丝锥材料、丝锥结构、螺纹底孔、切削液等方面研究如何提高钛合金小直径螺纹攻丝的效率,并得到相应的工艺参数,取得良好效果。     

Ni基变形高温合金小孔攻丝扭矩的试验研究

采用修正齿丝锥和标准丝锥对Ni基变形高温合金GH4 1 6 9难加工材料进行了小孔螺纹攻丝对比试验。试验结果表明 ,与标准丝锥相比 ,采用修正齿丝锥可显著减小攻丝扭矩 ,且切削锥角较大的修正齿丝锥加工效果较好     

汽车胀断连杆用挤压丝锥的优化设计与应用

为有效解决挤压丝锥在加工高强度非调质钢C70S6连杆挤压螺纹时易出现粘屑、攻丝扭矩大、螺纹孔粗糙度差和丝锥寿命短等问题,对挤压丝锥的关键结构参数和加工工艺进行优化,并用优化后的挤压丝锥进行切削寿命对比试验。结果表明,该优化设计可提高挤压丝锥加工C70S6材料连杆螺纹的使用寿命和提升产品质量。     

避免小丝锥折断的简便方法

在A3材料的工件上,攻M4以下的螺纹孔,尤其是盲孔,由于材料软而韧,加上丝锥轴线与工件表面的垂直度和螺纹深度不容易掌握,丝锥极易折断。我们采用如图示的攻丝管套,解决了这个问题。采用这种方法的特点是:丝锥轴线与工件表面的垂直度容易掌握,通过改变管套长度,便能达到自行控制攻丝的深度,避免了断丝攻的现象,特别对青年工人初学攻丝很有好处。     

圆柱表面攻丝的几种方法

零件在平面上攻丝,丝锥与零件表面的垂直度较易掌握。而在零件的外圆柱表面上攻丝,则要保证螺纹与零件轴线的垂直度和对称度要求,就较困难了。在多年的生产实践中,我们使用以下几种简单方法,取得了较好的效果。简单介绍以下: (1)丝锥引导法。图1为带有引导部分的丝锥,当螺纹底孔深度大于螺纹底孔孔径时使用。 (2)引导套引导法。图2为圆柱表面上螺纹孔有较深的沉孔时所采用的攻丝法。 (3)浮动引导法。图3所示为圆柱表面任意位置攻丝的浮动引导攻丝法。在螺纹长度小于螺纹外径,且又无沉孔的情况下特别有效。图中的浮动引导2为一浮动导向的攻丝辅具,其结构是一圆环,在圆环径     

紫铜零件小尺寸螺纹孔的攻丝分析

分析了直槽丝锥、螺旋槽丝锥、螺尖丝锥以及挤压丝锥的工作原理与结构特点,通过选择合适的丝锥、合理的攻丝钻头直径,并采用合理的攻丝操作方法,完全解决了紫铜零件小尺寸螺纹孔的加工工艺问题。     

不锈钢管件内螺纹攻丝加工要点

不锈钢管件上的内螺纹通常采用丝锥进行攻丝加工。由于不锈钢材质的粘性较高,断屑性能差,因此在攻丝过程中容易出现切屑刮伤工件螺纹或丝锥崩刃等现象,影响加工效率和螺纹质量。为了延长丝锥使用寿命,提高螺纹加工质量,应注意以下要点。     

手动攻丝定位导向装置的设计与应用

使用手动方式攻丝时,由于人的两手压力不均,平衡不好,很容易导致在攻丝过程中丝锥倾斜,丝锥与工件表面不垂直,造成手动攻丝攻出的螺纹孔倾斜、不正,发生歪曲,从而影响了攻丝精度及工件质量。设计了应用于手动攻丝时的一种定位导向装置,一是可以实现丝锥与螺纹底孔的精确定位,二是可以平衡手动攻丝时丝锥所受的压力,使丝锥轴线始终与工件表面保持垂直,有利于提高攻丝精度和速度,从而提高加工效率。     

转子式螺母自动攻丝机

现有结构的螺母自动攻丝机是按照所用刀具的种类、加工方式和工艺循环的控制元来分类的。自动攻丝机的结构取决于螺母的种类、攻丝精度(平均直径、垂直度和同轴度)、生产率以及刀具的耐用度。 在螺母自动攻丝机上,螺纹刀具基本上采用直柄丝锥和弯柄丝锥(切削式无屑滚压)两种形式。采用弯柄丝锥可以获得最高的生产率,但却不能获得高精度的螺纹。此外,弯柄丝锥的加工制造也较为复杂,且很难刃磨。采用直柄丝锥可以获得精度好的螺纹,但生产率较低。通过电液装置、电气装置或机械装置可以保证螺纹形成的工作周期。 在螺母生产的工艺过程中,攻丝是…     

硬质合金外螺纹的电火花成型机加工工艺探讨

结合硬质合金的材料特性,将电火花成型电极加工内外螺纹的工艺差异进行对比,分析硬质合金外螺纹电火花加工工艺难点,并提出合理的改进措施。再以电火花成型电极加工YG6硬质合金外螺纹为实例,运用改进方法成功加工出较高质量的外螺纹。结果表明:选取合适的峰值电流,改进加工电极结构是保证外螺纹加工质量的关键技术。最后对单电极电火花加工外螺纹的可行性工艺方案进行详细说明。     

硬孔攻丝用高性能先端丝锥的设计及应用

热后硬孔攻丝螺纹变形量小、尺寸稳定、强度高。该工艺方法对刀具强度要求较高,使用普通高速钢丝锥和螺纹铣刀加工时,普通高速钢丝锥无法承受热后硬孔攻丝所产生的大扭矩而频繁折断,报废率较高,同时螺纹铣刀成本高,不适合大批量生产。针对热后硬孔攻丝工艺复杂、成本高的问题,专门设计了硬孔攻丝用高性能先端丝锥,解决硬孔攻丝难题,并与其他种类丝锥进行了切削力对比。     

Hard turning: Parametric optimization using genetic algorithm for rough/finish machining and study of surface morphology

The present study reports the effect of different process parameters on machining forces, surface roughness, dimensional deviation and material removal rate during hard turning of EN31, SAE8620 and EN9 tool steels. Feed rate followed by hardness, cutting speed and nose radius-depth of cut significantly affected machining forces whereas feed rate had the largest effect on surface roughness. The four responses were subsequently optimized for both rough and finish machining using genetic algorithm to determine the optimum combination of input parameters. Machined surfaces were subsequently analyzed using XRD followed by analysis of grain size and crystallite size of the machined samples and SEM analysis. Higher chromium content was observed at the machined surface as manganese dissolves in cementite and may replace iron atoms in the cementite lattice after machining. High heat is generated when machining at higher cutting speeds causing severe strain. The depth of the white layer decreases with increasing tool nose radius and increases at larger feeds because of greater heat generation. The SEM observations showed a smooth pattern with very low undulations with almost no crack damage.     

国产电火花机床混粉加工试验研究

介绍利用国产普通电火花机床进行混粉电火花加工的试验研究。结果表明 ,混粉电火花加工不但能显著改善加工表面粗糙度 ,而且能显著提高加工效率     

超声纵扭辅助铣削高强铝合金表面润湿性能研究

针对超声辅助加工在工件表面形成微刻划表面可以提高高强铝合金表面的微结构性能的现象,进行了单激励旋转超声纵扭复合铣削表面微观结构的试验,基于水接触角理论和纵扭铣削运动学理论分析了加工参数对水接触角的影响;搭建了单激励超声纵扭铣削试验平台,采用正交试验法研究了不同加工参数对表面粗糙度、铣削力以及表面润湿性能的影响。结果表明：超声振幅为4μm时表面质量最佳,切削速度和进给量与表面粗糙度和水接触角呈正相关的关系;超声加工方式下的表面水接触角较普通方式更大,而在超声加工时低振幅加工比高振幅加工的表面水接触角大,当转速达到一定值时,高振幅和低振幅所加工的表面水接触角差别不大。合适的加工参数条件下超声纵扭加工方式可以降低加工表面的粗糙度,改变表面的润湿性。     

A reaming test for cutting fluid evaluation

As an alternative to tapping torque measurement and thread finish evaluation, a reaming test is suggested for the evaluation of the lubricating efficiency of cutting fluids. An investigation was carried out where results from tapping torque measurements were compared with those from measuring torque, feed force, and surface roughness in reaming. Two different tap geometries and two different reamer geometries were used. Technically-pure aluminium was used as the workpiece material and four laboratory water-based cutting fluids as well as a commercial cutting oil were investigated. The results show that lubricants have a significant and similar effect with respect to both tapping torque and reaming torque, when tools with straight flutes are used. In reaming, a more comprehensive picture of lubrication can be obtained if torque measurement is accompanied by determination of the surface roughness. In a subsequent investigation, the reaming torque and roughness test was used to evaluate two different water-based cutting fluids and a neat oil, using austenitic stainless steel as the workpiece material.     

往复运动速度规划算法对曲线磨削的影响研究

往复加工常见于磨削和刨削等金属切削中,加工过程的平稳性直接影响到产品的加工质量、能源效率乃至机床的寿命。首先探究往复(冲程)运动速度规划对运动过程平稳性的影响,在分析了常见速度规划运动学性能的基础上,针对磨削冲程运动的特点,提出通过改变急动度空间分布来降低柔性冲击对加工表面质量的影响,并设计了两种基于急动度连续的速度规划算法。在此基础上,研究了速度规划算法和磨削力平稳性、加工表面粗糙度和加工能耗间的关系,提出了通过改变加速度空间分布来降低加工能耗的方法。试验结果表明,往复运动速度规划和磨削力平稳性、加工表面粗糙度以及加工能耗均相关,通过改变急动度和加速度空间分布提高了磨削力平稳性和加工表面质量,降低了加工能耗。所提出的Ⅱ型速度规划综合表现优于其他规划,与梯形速度规划相比,切削力波动、加工表面粗糙度和电机驱动能耗均有较为显著的下降。     

Investigation on the effect of cutting fluid pressure on surface quality measurement in high speed thread milling of brass alloy (C3600) and aluminium alloy (5083)

The quality of a machined finish plays a major role in the performance of milling operations, good surface quality can significantly improve fatigue strength, corrosion resistance, or creep behaviour as well as surface friction. In this study, the effect of cutting parameters and cutting fluid pressure on the quality measurement of the surface of the crest for threads milled during high speed milling operations has been scrutinised. Cutting fluid pressure, feed rate and spindle speed were the input parameters whilst minimising surface roughness on the crest of the thread was the target. The experimental study was designed using the Taguchi L32 array. Analysing and modelling the effective parameters were carried out using both a multi-layer perceptron (MLP) and radial basis function (RBF) artificial neural networks (ANNs). These were shown to be highly adept for such tasks. In this paper, the analysis of surface roughness at the crest of the thread in high speed thread milling using a high accuracy optical profile-meter is an original contribution to the literature. The experimental results demonstrated that the surface quality in the crest of the thread was improved by increasing cutting speed, feed rate ranging 0.41–0.45 m/min and cutting fluid pressure ranging 2–3.5 bars. These outcomes characterised the ANN as a promising application for surface profile modelling in precision machining.     

导柱螺旋槽丝锥的设计及工艺方法

导柱螺旋槽丝锥与普通丝锥不同之处在于其带有导柱及螺旋式容屑槽,使其在使用中具有独特的优势,排屑顺畅,加工出的螺纹孔位置度和垂直度较高。本文着重论述了导柱螺旋槽丝锥的设计方法及加工工艺过程。     

Improvement of EDM efficiency with a new adaptive control strategy

In most of the commercially available EDM systems, the control parameters such as the electrode jump height and the discharge machining time between two consecutive electrode jump actions are set manually to constant values which can ensure stable machining even under the worst machining conditions. It is beneficial to keep the machining process stable, but much time is consumed in the electrode jump process. In order to improve the EDM efficiency, a new adaptive control strategy which directly and automatically regulates the electrode jump height and discharge machining time has been developed in this paper. Experimental results show that the adaptive control system can obviously improve the machining efficiency regardless of the surface area, shape, and depth of the machined dies. Meanwhile, the accuracy and surface roughness of the fabricated dies can be well retained.