基于切削技术的金刚石刀具磨损特征分析

金刚石刀具的磨损情况决定其使用寿命。用金刚石PCD刀具切削6061-T6镁铝合金工件,通过不同切削速度、切削深度、振动频率、刀具后角时的切削力及切削温度变化,研究不同刀具前后角、进给量、切削转速时的工件表面粗糙度及刀具磨损面积。结果表明:金刚石刀具的切削力和切削温度随切削速度、切削深度的增加而增大,随振动频率的增加而减小;刀具后角增大,金刚石刀具的切削力呈先下降而后缓缓上升趋势,但对切削温度的影响很小。当刀具前角为10°,刀具后角为8°,切削速度为0.46?m/s,切削深度为28?μm,进给量为0.10?mm/r,切削转速为4100?r/min,振动频率为22?kHz,切削振幅为9?μm时,金刚石刀具的磨损面积最小,磨损程度最低,使用寿命最长,但工件的表面粗糙度稍高。      

基于人工智能算法的最优加工表面粗糙度预测研究

以切削速度、进给量、切削深度、刀尖圆弧半径为设计变量,采用正交试验法进行了立方氮化硼(CBN)刀具干式车削冷作模具钢Cr12MoV的试验研究。利用神经网络的非线性拟合能力和遗传算法的全局寻优能力,建立了加工表面粗糙度预测模型并获得了使表面粗糙度达到最优的切削用量与刀尖圆弧半径组合。利用遗传算法获得的最优表面粗糙度值比田口方法和切削试验所获得的最佳表面粗糙度值分别降低了7.1%和17.2%。文中所采用的方法也为切削加工中刀具磨损、切削力和残余应力等问题的建模与参数优化提供理论参考。     

PCBN硬态加工表面粗糙度形成分析及实验

对聚晶立方氮化硼刀具硬态切削加工表面粗糙度形成进行分析,认为其加工粗糙度形成主要原因和普通切削不一样,切削残留、侧向塑流和机床系统振动是加工表面粗糙度形成的主要原因。通过试验和扫描电镜观察证明了：切削残留对粗糙度大小影响最大;切削条件不同导致侧向塑流发生程度不一样,对加工表面粗糙度有很大影响;进给量和刀尖圆弧半径的影响明显超过切削速度和切削深度。     

中断时效对7075铝合金切削表面质量及刀具磨损影响研究

目的 探究中断时效工艺对7075铝合金切削加工性能的影响,为中断时效工艺对材料切削加工性能的改善提供理论依据。方法 选取仅进行T6时效处理的试样作为对照组,通过扫描电镜(SEM)、X射线衍射仪(XRD)等手段对已加工表面质量、切削力及刀具磨损进行分析。结果 经不同时效处理后,7075铝合金的主要析出相为η(MgZn2)相,且相较于T6热处理工艺的7075铝合金,7075-T6I4铝合金表现出更高的衍射峰强度及更大的半高宽。在不同的时效处理条件下,表面粗糙度Ra均与切削速度呈负相关关系,而与切削深度、进给量呈正相关关系,仅T6时效处理时,表面粗糙度Ra随切削深度的增大呈先增大后减小再增大的变化趋势,在不同切削速度下,与T6时效处理相比,T6I4中断时效处理的表面粗糙度Ra最大降低了5.8%,而在不同切削深度和进给量下最大降低了1.9%和17.1%,且工件表面主要存在切屑黏附、微裂纹以及微孔洞等缺陷;切削力在切削速度为500~750 m/min时呈增大趋势,随后又逐渐减小,然而与切削深度、进给量之间则呈正相关关系,仅经T6I4中断时效处理后的y向切削力在进给量为0.06~0.08 mm/z时逐渐减小,随后呈增大的变化趋势。增大切削速度以及减小进给量均可有效改善刀具磨损程度,且在切削过程中刀具磨损形式主要表现为崩刃和黏结磨损。结论 与T6时效处理相比,T6I4中断时效处理表现出更好的表面质量、更小的切削力及更轻的刀具磨损,较大的切削速度和较小的进给量、切削深度有助于提高7075铝合金的切削加工性。     

工艺参数对单晶硅超精密加工切削力的影响

为了了解单晶硅超精密车削过程中不同切削参数及刀具前角对切削力的影响,利用单晶金刚石车刀对单晶硅进行单因素变量超精密车削试验。试验结果表明:进给量f和切削深度a_p对X、Y、Z方向的切削力F均有增大的趋势;而在切削速度v_c增加时,各方向的F逐渐减小;切削前角减小时,切削力反而增大。通过各因素对切削力F的变化幅值可以得到,对F影响较大的参数为a_p及f。选取最佳组合参数对单晶硅进行超精密切削试验,得到极为光滑的表面。     

300 M超高强钢车削加工表面质量

目的研究切削参数对300M超高强度钢加工表面质量的影响。方法选用硬质合金刀具车削加工300M超高强度钢,研究切削参数对表面加工硬化、残余应力及表面粗糙度的影响。通过HXD-1000显微硬度检测仪、X-350A型X射线应力测试系统、TR240表面粗糙度测量仪对实验过程进行检测分析。通过单因素试验研究影响表面粗糙度的主次因素,并通过正交试验,以进给量f、切削速度v、刀尖圆弧半径rε、背吃刀量a_p为变量建立表面粗糙度的预测模型。结果背吃刀量a_p=0.2 mm,切削速度v为60~120 m/min,进给量f为0.1~0.25 mm/r时,300M钢经切削加工后,维氏硬度在467~550HV范围内变化。切削速度从60 m/min增大至200 m/min时,表面残余应力从压应力-59.13 MPa变为拉应力257.33 MPa,次表层残余应力的最大残余压应力从-147.46 MPa增大到-422.65 MPa,并且层深至50μm左右处,工件材料的加工变质层结束。结论表面硬度随着进给量和切削速度的增大而减小,并且越往里层,硬度越低,直至达到基体的硬度。影响表面粗糙度的最主要因素为进给量,其次是刀尖圆弧半径,再次为切削速度,背吃刀量对表面粗糙度的影响最小。建立的表面粗糙度预测模型通过了试验验证,具有很高的加工精度。     

PCD刀具加工氮化硅陶瓷孔的试验研究

使用PCD刀具对氮化硅陶瓷内孔进行切削试验,首先研究氮化硅陶瓷材料的去除机理,主要包括脆性去除和塑性去除,且以脆性去除为主。其次,研究刀具前角、切削速度、背吃刀量和进给量对切削力的影响。结果表明:刀具前角对切削力的影响不明显;随切削速度、背吃刀量和进给量的增加,切削力均增大,且背向力大于进给力和主切削力。最后,重点研究各参数对内孔侧壁表面粗糙度的影响。结果表明:进给量对表面粗糙度的影响最显著,其次是背吃刀量和切削速度,刀具前角几乎没有影响,且当刀具前角为-5°,切削速度为32.97m/min,背吃刀量为0.10mm,进给量为0.08mm/r时,可以得到较好的表面粗糙度和刀具寿命的综合效益。      

一种不锈钢材料车削的表面粗糙度试验与研究

针对不锈钢材料切削加工的难题，采用回归正交表设计试验方案。采用回归方法对试验数据进行分析，建立表面粗糙度模型。利用自编程序迅速、准确地完成试验数据的选取、处理，并进行结果分析。结果表明：切削速度、进给量、车刀刀尖半径对表面粗糙度的影响明显，而切削深度对表面粗糙度的影响不明显；增大切削速度、车刀刀尖半径可降低表面粗糙度，增大进给量会使零件表面粗糙度变大。试验结果对不锈钢的加工有重要的参考价值     

基于正交试验的PCD刀具加工铝合金时切削性能的研究

通过PCD刀具切削铝合金的正交试验，分析刃磨刀具用砂轮的结合剂和切削用量对切削力与工件表面质量的影响。结果表明：进给量与砂轮结合剂对切削力和工件表面粗糙度影响较大，而切削速度与切削深度的影响相对较小，优方案为陶瓷结合剂金刚石砂轮刃磨的PCD刀具在切削用量v=88．45m／min，切削深度αp=0．1mm，进给量f=0．032mm／r时，工件表面粗糙度最小，同时切削力也较小。     

微棱镜反光阵列超声振动刨削试验研究

通过超声振动刨削加工微棱镜阵列的正交试验,分析了刀具材料、刀具工作前角、切削速度、第三次切削深度对微棱镜阵列表面质量和刀具寿命的影响。结果表明：刀具材料是试验指标粗糙度Ra、V形槽夹角β、加工后刀尖圆弧半径R的第一影响因素;第三次切削深度ap是磨损量NB的第一影响因素;切削速度v是四个试验指标的第二影响因素;当刀具材料选用PCD,刀具前角为-3.8°,切削速度为900mm/min,第三次切深为2μm时,微棱镜阵列表面加工质量好,刀具寿命高。     

Cutting conditions for finish turning process aiming: the use of dry cutting

To avoid the use of cutting fluids in machining operations is one goal that has been searched for by many people in industrial companies, due to ecological and human health problems caused by the cutting fluid. However, cutting fluids still provide a longer tool life for many machining operations. This is the case of the turning operation of steel using coated carbide inserts. Therefore, the objective of this work is to find cutting conditions more suitable for dry cutting, i.e., conditions which make tool life in dry cutting, closer to that obtained with cutting with fluid, without damaging the workpiece surface roughness and without increasing cutting power consumed by the process. To reach these goals several finish turning experiments were carried out, varying cutting speed, feed and tool nose radius, with and without the use of cutting fluid. The main conclusion of this work was that to remove the fluid from a finish turning process, without harming tool life and cutting time and improving surface roughness and power consumed, it is necessary to increase feed and tool nose radius and decrease cutting speed.     

Predictive machinability models for a selected hard material in turning operations

In this paper, empirical models for tool life, surface roughness and cutting force are developed for turning operations. Process parameters (cutting speed, feed rate, depth of cut and tool nose radius) are used as inputs to the developed machinability models. Two important data mining techniques are used; they are response surface methodology and neural networks. Data of 28 experiments when turning austenitic AISI 302 have been used to generate, compare and evaluate the proposed models of tool life, cutting force and surface roughness for the considered material.     

新型微坑车刀切削AISI4140残余应力影响因素分析研究

为了探究切削用量对新型微坑车刀切削工件表面残余应力的影响规律,应用AdvantEdge切削仿真软件,结合单因素和正交实验,通过微坑车刀和原车刀切削AISI_4140仿真及实验验证。结果表明,原车刀和微坑车刀残余拉应力随切削速度增大,先增大后减小,随进给量的增大而减小,总体上,微坑车刀切削工件残余拉应力更小。残余压应力随切削速度增大,微坑车刀切削工件先增大后减小,随进给量增大先增大后减小。原车刀几乎不变。切削用量对微坑车刀切削工件残余应力影响,进给量最大,切削速度次之,切削深度最小。通过实验验证,相同切削条件下,微坑车刀降低了加工工件表面残余拉应力,提高了加工工件表面质量,一定程度提高了工件的服役寿命。     

微沟槽织构对切削力和表面粗糙度的影响

为研究微织构对切削过程中产生的切削力和已加工表面粗糙度的影响,在聚晶立方氮化硼(PCBN)刀片前刀面制备与主切削刃平行的宽度为32.6μm的微沟槽织构。分别用微沟槽刀具和无织构刀具在主轴转速为450、500、600 r/min的条件下切削淬硬钢GCr15,分析切削力和已加工表面粗糙度。试验结果表明:微沟槽改善了刀具的切削性能,主切削力、进给力和切深力均小于无织构刀具;进给力、切深力随着主轴转速的增加均变大,主切削力表现为先减小再增大;用微沟槽织构刀具切削的已加工表面粗糙度大于无织构刀具,表明微沟槽不利于获得表面质量较好的工件;随着主轴转速增加,微沟槽刀具和无织构刀具切削的表面粗糙度均减小。     

Cutting performance of diamond tools during ultra-precision turning of electroless-nickel plated die materials

This study is an attempt (a) to observe the wear characteristic of diamond tool with 200 km cutting distance and to study the effects of wear on the surface roughness and cutting forces and (b) to optimize various cutting parameters such as depth of cut, feed rate, spindle speed and phosphorus content. The experimental results showed that tool wear was not so significant although some defects on rake face were observed after cutting 15.6 km. Further cutting showed that the surface roughness increases with cutting distance, and that the cutting forces were larger than thrust force at the beginning of cutting, but after cutting 130 km, thrust force became larger and increased rapidly. It was also observed that forces increase with the increase of depth of cut, spindle speed and feed rate, and decrease with the increase of phosphorus content of the plating. Depth of cut has no significant effect on surface roughness, while it increases with increase of feed rate and decreases with the increase of percentage of phosphorus content in the workpieces. In case of spindle speed, surface roughness decreases with the increase of spindle speed up to a certain value and then starts to increase with the increase of spindle speed.     

Cutting temperature of ceramic tools in high speed machining of difficult-to-cut materials

This paper deals with an experimental and analytical investigation into the different factors which influence the temperature distribution on Al₂O₃---TiC ceramic tool rake face during machining of difficult-to-cut materials, such as case hardened AISI 1552 steel (60–65 Rc) and nickel-based superalloys (e.g. Inconel 718). The temperature distribution was predicted first using the finite element analysis. Temperature measurements on the tool rake face using a thermocouple based technique were performed and the results were verified using the finite element analysis. Experiments were then performed to study the effect of cutting parameters, different tool geometries, tool conditions, and workpiece materials on the cutting edge temperatures. Results presented in this paper indicate that for turning case hardened steel, increasing the cutting speed, feted, and depth of cut will increase the cutting edge temperature. On the other hand, increasing the tool nose radius, and angle of approach reduces the cutting edge temperature, while increasing the width of the tool chamfer will slightly increase the cutting ege temperature. As for the negative rake angle, it was found that there is an optimum value of rake angle where the cutting edge temperature was minimum. For the Inconel 718 material, it was found that the cutting edge temperature reached a minimum at a speed of 510 m/min, and feed of 1.25 mm/rev. However, the effect of the depth of cut and tool nose radius was almost the same as that determined in the turning of case hardened steel. It was also observed in turning Inconel 718 with ceramic tools that, cutting forces and different types of tool wear were reduced with increasing the feed.