钛合金冷风加工切削力试验研究

采用正交试验方法,组合多组切削参数,在冷风降温条件下,对切削力实时数据进行采集.直观上,对比分析了干式切削力和冷风切削力的大小;理论上,运用最小二乘法原理,对实验数据进行多元线性回归分析,建立了适用于冷风加工条件下的切削力经验公式,从而找到了冷风条件下切削力的变化规律.     

多元回归法建立切削力经验公式

本文介绍了多元回归法建立切削力多因素经验公式的方法,并将其编制成计算机程序。实验证明,该方法是建立各种多因素经验公式的有效、准确的方法。     

微机建立切削力多因素经验公式

本文介绍了利用微机建立切削力经验公式的方法,实验考证其是建立各种多因素经验公式准确、有效的方法。     

“切削力确立与经验公式建立”的计算机辅助分析及数据处理

为了提高学生应用切削力经验公式解决实际问题的能力,提出了“切削力确立与经验公式建立”实验课计算机辅助教学新模式,即在大学机械制造专业金属切削原理的实验课实施新的计算机辅助分析、计算机辅助数据处理教学方法.详细介绍了建立3个经验公式的过程,以及独创的切削深度与切削力计算机辅助二维分析图、进给量与切削力计算机辅助二维分析图的应用情况.计算机辅助“切削力确立与经验公式建立”的应用,不仅解决了以往数据处理存在的繁琐、准确性差、耗费时间长、数据分析不直观等难题,还有助于学生对复杂抽象的切削力及切削力与3个切削用量的深层量化关系等内容的理解.该教学模式还可为相似的专业实验课的教学改进提供新思路.     

基于无心车床主轴电机电流的钛合金切削力经验公式的实验研究

针对目前无心车床钛合金切削力计算公式推导的困难性和复杂性,通过测量主电机电流的实验方法来探索难加工材料钛合金的切削规律,打破了传统的测量切削力的实验平台,解决了传统方法中实验平台搭建过程的难题。同时以空心主轴电机电流为主要实验数据,结合切削深度以及进给速度等实验数据,在SPSS软件中进行线性回归分析,拟合出了切削力经验公式,验证了该经验公式在实际的加工中的指导意义,为进一步研究钛合金的切削机理奠定了研究基础。     

永磁材料套孔加工轴向进给力经验公式的建立

钕－铁－硼永磁材料的性能优于所有传统永磁体材料，它可使仪器仪表电子设备的元器件微型化，具有广阔的发展前景。钕－铁－硼永磁材料比较昂贵，为节约原材料，加工时应尽可能减小去除量，尤其是进行孔加工时，应采用套孔加工，芯柱可留作他用。用套料刀具在实心材料上环形切割称为套孔加工，套孔与钻孔相比不仅能减少轴向载荷，提高生产效率，而且能减少材料的损耗。用金刚石工具加工钕－铁－硼永磁材料是一种十分有效的加工方法。刀具结构如图所示。刀头上电镀金刚石并开有４个槽，在套孔时整个刀具的端面都参与切削，轴向抗力与工具的轴…     

套料钻头耐用度经验公式建立

一、前言 用套料钻头在实心材料上钻孔的方法称为套料加工。见附图。 浅孔套料适用于φ60～120mm,且长径比L/D=1～3的通孔加工。对于直径大于50mm的孔,若用手动进给钻削,操作者劳动强度大。若机动进给钻孔,则走刀抗力大。同时,用麻花钻头钻孔的表面粗糙度一般为Ra12.5以上,且孔的几何精度低,生产效率低。 鉴于上述原因,我们设计并制造了浅孔套料钻头,在生产中得到了广泛应用。与麻花钻头钻孔比较,生产效率提高3～6倍,加工精度可提高1～2级,且大大减轻了劳动强度,并节省了工件材料。 应用实践中发现,正确的选择切削用量（切削速度v和进给量f）是更好发挥套料钻头钻孔切削性能的重要一环。     

难加工材料加工切削力机理研究现状

难加工材料具有强度高、强化因数高、塑性高、韧性好、导热系数低、耐磨性好等优点,切削时会出现大切削力,刀具磨损严重。对难加工材料加工切削力机理的研究现状进行了介绍,具体包括直角或斜角切削的切削力、立铣刀切削力理论预报模型。     

高速加工切削力影响因素的有限元分析

通过理论分析和有限元模拟,对AL6061铝合金高速切削过程中的切削力影响因素进行了比较分析.在其他条件不变的前提下,分别改变摩擦系数、切削速度、背吃刀量和进给率,模拟结果表明:随着摩擦系数、背吃刀量和进给率的增加,切削力逐渐增大.对结果进行回归分析得到,切削力和进给率成线性关系,背吃刀量影响最大,进给率次之,摩擦系数最...     

新一代数控车床样机切削力测试试验研究

设计了切削力测试试验,对数控车床切削45钢切削用量对切削力的影响进行了试验研究,重点分析了切削用量对主切削力的影响规律。设计了切削用量对切削力影响单因素试验和正交试验,并对试验结果进行了分析,根据正交试验结果对主切削力经验公式进行了拟合,结果表明:切深和进给速度对切削力的影响显著,切削速度对切削力的影响不显著,该经验公式具有较高的预测精度。     

低温MQL技术在TA15铣削加工中的应用研究

通过在冷却液与低温MQL两种方式条件下,对TA15钛合金材料进行切削试验研究发现:低温MQL状态下加工工件使用的刀具切削寿命更长,工件的切削效率更高,加工的表面质量更好,变形更小.但是其在加工过程中,浅切冷却具有不适应性、加工中产生附加产物对环境的影响、深腔结构的加工冷却不充分等方面具有一定局限性,需进一步研究.     

小直径铣刀高速铣削淬硬模具钢不同走刀方式下切削力和加工效率的研究

高速加工是制造技术的一次革命性变革,是当今机械加工技术不可抗拒的发展潮流.小直径铣刀高速加工硬质模具钢时不同的切削条件及切削方式又是影响切削力的重要因素之一.本文主要研究刀具以不同走刀方式,在圆弧拐角处改变不同的进给速度铣削淬硬钢带岛屿的型腔时对切削力、及加工时间的影响情况,从而得出在同样的切削条件下摆线式走刀时刀具所受到的切削力较小,但是其加工效率也较低,相比之下圆弧走刀时刀具所受到的切削力较大而切削效率却较高的结论.故在高速加工时从保护刀具的角度出发易选用摆线走刀方式.     

非圆车削的解析测力方法

针对最小相位及非最小相位受控系统,分别提出了相应算法,根据系统输出位置信号及输入的控制力信号,辨识出动态切削力信息。不使用测力传感器,从而消除了附加测力传感器所产生的不利因素,为深入研究数控非圆车削加工特性及动态切削力误差补偿提供了一种新手段。     

机械加工中切削力预报分析

切削力的准确预报不仅对合理选择切削用量、刀具几何参数有着重要作用，还是刀具磨损状态的关键指标。在总结切削力预报方法的裁础上，分析各种方法的优缺点、研究现状及适用场合，为进一步切削加工的理论研究打下基础。     

高锰钢切削刀具的设计

高锰钢切削极易产生硬化层,很难加工。在生产实践中,通过合理地选择刀具材料、刀具结构、切削用量等,可以很好解决高锰钢难加工的问题,保证了高锰钢的加工质量。     

An improved cutting force model for micro milling considering machining dynamics

Micro milling, as a versatile micro machining process, is kinematically similar to conventional milling; however, it is significantly different from conventional milling with respect to chip formation mechanisms and uncut chip thickness modelling, due to the comparable size of the edge radius to the chip thickness, and the small per-tooth feeding. Considering tool runout and dynamic displacement between the tool and the workpiece, the contour of the workpiece left by previous tool paths is typically in a wavy form, and the wavy surface provides a feedback mechanism to cutting force generation because the instantaneous uncut chip thickness changes with both the vibration during the current tool path and the surface left by the previous tool paths. In this study, a more accurate uncut chip thickness model was established including the precise trochoidal trajectory of the cutting edge, tool runout and dynamic modulation caused by the machine tool system vibration. The dynamic regenerative effect is taken into account by considering the influence of all the previous cutting trajectories using numerical iteration; thus, the multiple time delays (MTD) are considered in this model. It is found that transient separation of the tool-workpiece occurring at a low feed per tooth, caused by MTD and the existing cutting force models, is no longer applicable when transient tool-workpiece separation occurs. Based on the proposed uncut chip thickness model, an improved cutting force model of micro milling is developed by full consideration of the ploughing effect and elastic recovery of the workpiece material. The proposed cutting force model is verified by micro end milling experiments, and the results show that the proposed model is capable of producing more accurate cutting force prediction than other existing models, particularly at small feed per tooth.     

Wear characteristics of ceramic cutting tools in machining steel

Some ceramic materials such as Al₂O₃ which have a high compressive strength, hardness and chemical stability came into use industrially in the middle of this century as powder metallurgy produced indexable cutting tool inserts. These early ceramic tools were inherently weak in tension, impact and dynamic loading owing to their low tensile strength, toughness and transverse rupture strength; because of this their application was limited to medium productivity operations and work materials of softer grades. However, the technology of ceramic cutting tools has made great strides in the last few years through substantial improvements in their strength, toughness and wear resistivity. These modern ceramic tools have found wide and economic applications in high production machining of both cast iron and steels.In this paper the constructional characteristics of some modern ceramic tools and their wear behaviour and overall performances in machining mild steel at both low and high speeds are presented. The comparative results obtained are reported and discussed.     

A cutting force model considering influence of radius of curvature for sculptured surface machining

A new cutting force model considering influence of radius of curvature is introduced in this research for sculptured surface machining with ball-end mill. In this model, first the whole cutting region near the cutter contact (CC) point on the sculptured surface is approximated by a spherical surface, and the radius of this spherical surface is used as the radius of curvature at the CC point. Then equations to estimate the cutting forces at a differential element on the cutting edge are established. By obtaining the cutter-workpiece contact areas based on geometries of the cutter and the sculptured surface, the mathematical model for estimating the total cutting forces in different directions is then developed. Experiments have also been conducted to measure the cutting forces considering different radii of curvatures on the sculptured surfaces. The analytically estimated cutting forces match well with the actual cutting forces obtained through experiments.