硬质合金可转拉车刀片UG型断屑槽断屑机理的研究

本文采用接触图形法对硬质合金可转位车刀片ＵＧ型断屑槽的断屑机理进行了实验研究。结果表明：由于采用了根据不同切削深度和进给量巧妙改变有效槽宽、使切屑横截面弯曲呈拱形、弹形挡屑等措施，ＵＧ型断屑槽具有断屑范围较宽、在进给量较大时不易出现过分断屑等特点。此外，文中还对化学气相涂层刀片的ＵＧ型断屑槽在切削速度明显提高以后断屑范围的变化进行了研究。文中给出的ＵＧ型断屑槽的断屑范围图可供实际选用。     

可转位刀片复杂断屑槽断屑机理探讨

本文采用接触图形法和切屑折断性模糊估计等方法，对国外流行的可转位刀片复杂断屑槽的断屑机理进行了实验研究。研究结果表明：为了扩大断屑范围、改善断屑性能，这些断屑槽均采取了根据不同吃刀量和进给量改变有效槽宽，使切屑横截面弯曲、弹性挡屑、断屑槽形状、棱带宽度和刀尖圆弧半径的有机结合等措施。这些对于新型断屑槽型的开发具有重要意义。     

复合断屑槽型结构及双槽刀片断屑性能试验研究

现代可转位刀片的断屑槽型开始越来越多地使用复合断屑槽型结构。在本文中,我们首先介绍了几种比较典型的复合式断屑槽型：双槽、刀尖部分向前突起的结构、波浪形后背结构。然后采用最典型的复合式槽型─—双槽进行试验研究,并对其切削力和断屑性能分析说明。     

凸包型断屑槽的研究与设计

本文建立了可转位刀片上反屑面为凸曲面断屑槽的截面模型──凸包型断屑槽，讨论了该模型各参数变化对切屑向上卷曲半径的影响，并对其截面参数设计进行了探讨。结果表明，本文提出的新的断屑槽截面设计方法简单、方便，具有实用价值．     

立铣刀断屑槽对切削性能影响规律试验研究

采用析因试验法研究断屑槽结构的制备对整体式立铣刀切削性能的影响。选取2把断屑槽分布不同的刀具,以铣刀主轴转速、径向切削深度、每齿进给量为主要因素,建立正交铣削试验。结果表明：断屑槽分布密集的铣刀适合用于加工精度要求不高的零件;断屑槽分布稀释的铣刀,适合用于半精加工要求的工件;对比分析切屑形貌和表面质量,得到用断屑槽分布稀疏的刀具铣削工件时可获得较好的表面质量。     

论刀具磨损量与断屑槽断屑的关系

本文通过实验研究和理论分析,讨论了前、后刀面磨损量对断屑槽断屑效果的影响及断屑槽槽形与磨损量的关系,还讨论了改变槽形以减少磨损量、提高刀具寿命并达到最佳断屑效果的断屑槽的设计原则。图4幅。     

错齿BTA中间齿断屑槽的实验研究

通过改变错齿BTA中间齿断屑槽槽宽L,来研究中间齿断屑的问题。用3支中间齿断屑槽槽宽不同的错齿BTA在切削速度为62.8 m/min,进给量为0.2 mm/r下对45钢进行钻削。通过对切削力和切屑的分析,得出错齿BTA中间齿断屑槽槽宽L对中间齿断屑有影响。     

刀具断屑槽对切削过程影响的数值模拟

本文通过有限元法模拟切削过程,对硬质合金刀片断屑槽在切削过程中的影响做了研究。结果表明采用平滑的槽型曲面有利于降低主切削力;断屑槽能够降低轴向力和径向力,进而可以帮助提高加工精度和工件的表面质量。切削过程中,有断屑槽的刀片表面等温线分布集中,而没有断屑槽的刀片表面有多个最高温度区域且温度更高,不利于刀片的使用寿命。另外,有断屑槽的刀片所产生切屑的有效应力、有效应变更大,更适合于加工塑性好的材料。     

精加工刀片槽型的研究：解决小切深小进给的断屑问题

为了解决小切深小进给的断屑问题这一技术难题,该文从二维槽型的断屑机理出发,引进三维槽型促成断屑的主要的三个几何要素——斜槽、小凸起与波形刃,并对此三者进行了理论分析,在理论分析的基础上提出了精加工三维刀片新槽型方案。图13幅,表1个。     

液压振动断屑装置在自动线上的应用

针对机床切削加工自动线中，如何将切屑折断成一段段较短的断屑的问题，采用了液压振动断屑装置。本文对液压系统带动凸轮振动断屑的工作原理进行了论述。     

近年来关于硬质合金刀片切屑控制研究的新成果

在当代技术背景下，对切屑控制问题进行深入的研究，具有重要的意义。研究的内容包括三个方面，即切屑的生成学、切居卷曲以及切屑的折断力学。本文主要阐述近年来关于硬质合金刀片切屑流向、切屑卷曲以及切清折断研究的一些新成果．     

Analysis on high-speed face-milling of 7075-T6 aluminum using carbide and diamond cutters

This research is concerned with the analytical and experimental study on the high-speed face milling of 7075-T6 aluminum alloys with a single insert fly-cutter. The results are analyzed in terms of cutting forces, chip morphology, and surface integrity of the workpiece machined with carbide and diamond inserts. It is shown that a high cutting speed leads to a high chip flow angle, very low thrust forces and a high shear angle, while producing a thinner chip. Chip morphology studies indicate that shear localization can occur at higher feeds even for 7075-T6, which is known to produce continuous chips. The resultant compressive residual stresses are shown for the variation of cutting parameters and cutting tool material. The analysis of the high-speed cutting process mechanics is presented, based on the calculation results using extended oblique machining theory and finite element simulation.     

Performance evaluation of chip breaker utilizing neural network

The continuous chip generated during turning operation deteriorates the workpiece precision and causes safety hazards for the operator. Appropriate control of the chip shape becomes a very important task for maintaining reliable machining process. In particular, effective chip control is necessary for a CNC machine or automatic production system because any failure in chip control can cause the lowering in productivity and the worsening in operation due to frequent stop. Therefore, a grooved chip breaker has been widely used for obtaining reliable discontinuous chips. In general, in order to develop a new cutting insert with a chip breaker, extensive time, research, and expense are required because several processes such as forming, sintering, grinding, and coating of products as well as different evaluation tests are necessary. In this study, the performance of commercial chip breakers was evaluated using a neural network that was trained through a back propagation algorithm. Important form elements (depth of cut, land, breadth, and radius) that directly influenced the chip formation were chosen among commercial chip breakers, and were used as input values of the neural network. As a result, the performance evaluation method has been developed and applied to commercial tools, which resulted in excellent performance. If the training data in the neural network is collected with greater consideration given to the effect of cutting conditions and the performance of chip breakers, it can be used for the design of chip breakers in the future.     

Wear behaviour of cryogenically treated tungsten carbide inserts under dry and wet turning conditions

Cryogenic treatment has been acknowledged as a means of extending the life of tungsten carbide inserts but no study has been reported in open literature regarding the effect of coolant on the performance of cryogenically treated tungsten carbide inserts in turning. In order to understand the effect of coolant, a comparative investigation of the wear behaviour of cryogenically treated tungsten carbide inserts in dry and wet orthogonal turning has been carried out in this study. The commercially available uncoated square-shaped tungsten carbide inserts with chip breakers were procured and cryogenically treated at ?196 °C and the cutting tests were executed in accordance to the International Standard Organisation, ISO 3685-1993 for continuous and interrupted machining mode. The criterion selected for determining the tool life was based on the maximum flank wear (0.6 mm) and the selection of cutting conditions was made to ensure the significant wear at a suitable time interval. The results showed that cryogenically treated tungsten carbide inserts performed significantly better in wet turning conditions under both continuous and interrupted machining modes especially at higher cutting speeds. A considerable increase in tool life was also recorded in interrupted machining mode as compared with continuous machining mode.     

铝合金高速铣削过程切屑成形机制研究

高速铣削加工中,切削力、切削热和机床振动等被广泛研究,而对切屑的研究相对较少.本文针对立铣刀高速铣削的特点,对切屑的成形进行了研究.根据理论分析,在UG环境下对切屑进行了绘制,其形状与实际切屑基本吻合,证明了研究方法的可靠性.通过切屑的研究反馈设计过程,对立铣刀的结构设计提供支持.     

–50 ℃冷风条件下抛光硬质合金刀片加工TC4钛合金的表面粗糙度分析

目的提高硬质合金刀片加工TC4钛合金的表面质量。方法利用化学机械抛光技术对传统磨削的硬质合金刀片分别进行粗抛、半精抛和精抛处理,运用正交试验法,在常温干切和–50℃冷风条件下,分别采用传统磨削的硬质合金刀片(磨削刀片)与化学机械抛光的硬质合金刀片(抛光刀片)进行切削TC4钛合金正交试验,利用方差分析法分析切削参数对已加工表面粗糙度Ra的影响。运用多元线性回归方法建立磨削刀片、抛光刀片在常温干切和–50℃冷风条件下切削TC4钛合金已加工表面粗糙度Ra的经验预测模型。结果硬质合金刀片前刀面通过粗抛、半精抛和精抛后,刀片前刀面的表面粗糙度Ra为19 nm。当切削参数相同时,磨削刀片在–50℃冷风条件下切削TC4钛合金的已加工表面粗糙度,比常温干切条件下平均降低了35.9%;抛光刀片在–50℃冷风条件下切削TC4钛合金的已加工表面粗糙度,比常温干切条件下平均降低了43.5%。在常温干切条件下,抛光刀片比磨削刀片切削TC4钛合金的已加工表面粗糙度平均降低了19.2%;在–50℃冷风条件下,抛光刀片比磨削刀片切削TC4钛合金的已加工表面粗糙度平均降低了28.7%。抛光刀片在–50℃冷风条件下切削TC4钛合金的已加工表面粗糙度Ra,比磨削刀片在常温干切条件下切削TC4钛合金的已加工表面粗糙度Ra平均降低了54.4%。结论采用对硬质合金刀片表面进行化学机械抛光技术和以–50℃冷风为切削介质的组合工艺,可有效降低TC4钛合金已加工表面粗糙度。     

Effects of cooling air temperature on cryogenic machining of Ti-6Al-4V alloy

This paper presents experimental investigations on influence of different coolant strategies such as dry, wet, minimum quantity lubrication (MQL) and MQL with cooling air on performance in milling of the Ti-6Al-4V alloy with uncoated cemented carbide inserts. Cutting force, tool wear, surface roughness and chip morphology are experimentally studied to compare the effects of different cooling air temperatures. The results showed that minimum quantity lubrication (MQL) with cooling air significantly reduces cutting force, tool wear and surface roughness. Unfortunately, MQL (without cooling air) condition cannot produce evident effect on cutting performance, and flaking wear on the flank surface of the insert has been found under this condition. Four different cooling air temperatures are used to investigate the effects of cooling air temperature on the machinability characteristics of Ti-6Al-4V alloy. Based on the experimental results, MQL with cooling air of −15 °C provides more favourable effects compared to other cooling air temperatures (0 °C, −30 °C,−45 °C). Short chips are produced under MQL with cooling air conditions due to the high velocity of cooling air enhances the chip brittleness for easy chip breaking, and the effective penetration of lubricant to the chip-tool interface results in lower friction. However, due to the dramatic increase in chip hardness at lower temperature, MQL with cooling air environments cannot promote chip curl to some extent.     

The influence of minimum quantity of lubrication (MQL) on cutting temperature,chip and dimensional accuracy in turning AISI-1040 steel

In metal industries, the use of cutting fluid has become more problematic in terms of both employee health and environmental pollution. But the use of cutting fluid generally causes economy of tools and it becomes easier to keep tight tolerances and to maintain workpiece surface properties without damages. Because of them some alternatives has been sought to minimize or even avoid the use of cutting fluid in machining operations. Some of these alternatives are dry machining and machining with minimum quantity of lubrication (MQL). This paper deals with experimental investigations in the role of MQL on cutting temperature, chip formation and product quality in turning AISI-1040 steel at different industrial speed-feed combinations by uncoated carbide insert. The results have been compared with dry machining and machining with soluble oil as coolant. The experimental results indicate that such MQL enables substantial reduction in the cutting temperature, dimensional inaccuracy depending upon the levels of the cutting velocity and feed rate. It was also noted that the chip formation and chip–tool interaction become more favorable under MQL condition. Therefore, it appears that MQL, if properly employed, not only provides environment friendliness but can also improve the machinability characteristics.