应力分散槽

由于硬质合金和刀杆材料的线膨胀系数不同,当焊接硬质合金刀片于刀杆时,如车削轴承套圈用的沟刀、槽刀、倒角刀等刀具,易产生热应力集中,硬质合金刀片出现裂纹,严重影响车刀质量。 为了避免硬质合金车刀焊接缺陷的产生,可对上述车刀刀杆作如下改进:在刀杆焊接刀片的部位开一小槽(具体尺寸根据刀片大小确定)。此     

机夹可转位车刀的结构、几何参数及切削性能分析

1车刀的结构 机夹可转位车刀是将可转位硬质合金刀片用机械的方法夹持在刀杆上形成的车刀,一般由刀片、刀垫、夹紧元件和刀体组成(见图1).     

C650车床用机夹车刀

大型机床上使用机夹刀具目前还不很普遍,我厂车工杨国武同志为革命钻研技术,最近研制成功一种大型车床使用的机夹强力车刀。这种车刀是用普通焊接刀的硬质合金刀片直接装卡在刀杆上,可重磨,有60°和90°两种,在C650车床上作粗车、半精车用。附图为90°机夹强力车刀。A313(YT15)刀片通过刀垫支撑在刀杆上,刀片上有压板,后面     

可调整切削角度的装配式车刀

附图所示机夹硬质合金可转位刀片的装配式车刀由于采用了可更换的刀座,所以同一把刀具能适用于多种类型尺寸的可转位刀片,从而扩大了它的工艺范围,增加了刀具的通用性,并可减少机床上刀具的品种与数量。该车刀是由刀头、刀片、刀垫、刀座、压板、齿板和刀杆本体等元件组成。刀头1与刀杆本体14通过螺钉10连结,刀头可相对于刀杆本体回转,这样     

硬质合金刀片加工中的问题

硬质合金刀具的加工,最重要的是在刀杆上焊接刀片和焊刀片以後的硬质合金刀片的加工。这些工序决定着刀具的质量、生产效率和成本。 对这些工序若控制不当,常常会引起硬质合金刀片产生裂痕、断裂以及刃口有锯形现象。要防止上述缺点,必须注意以下几个问题。 1.硬质合金在焊接前的质量问题: 硬质合金本身的质量对产生裂痕也有一定的影响,在制造中硬质合金刀片本身已经有了缺陷,如刀片有弯曲、气孔等,则当然不能保证刀具的质量。 2.硬质合金的焊接问题: (1)焊接时要注意加热或冷却速度的影响: 在焊接硬质合金刀片时,其加热或冷却速度对产生裂…     

机夹重磨式螺纹车刀

<正> 图示的机夹重磨式螺纹车刀,系采用普通刀片,用机械夹固方法夹持在刀杆上使用的车刀。它是出带弹性切口槽的刀杆4、拉紧螺钉3、消振垫5和硬质合金切削刀片1等零件所组成。刀杆前端铣有燕尾槽2,以便安放切削刀片和消振垫之用。消振垫的材料可采用软铅,它有支持切削刀片和吸振的作用。燕尾形刀槽可防止刀片在切削力的作     

硬质合金车刀焊接方法

过去焊接硬质合金刀具,用铜片硼砂作为焊药,用乙炔氧焰铜焊法。这一方法比较简单。在焊接时先用四氯化炭(CCl4)将刀杆焊接部分洗刷,在洗刷後加上一层硼砂,剪铜皮一块放在刀片下,然後加热刀杆部分(图Ⅰ)因为刀杆体积较大,吸收热量较剧。铜将熔解时,再在刀片上加热(图2),使刀杆焊药刀片部分温度在1080～1100℃之间。 然後用尖端压住刀片,使其凝固(图3)。这样一天只能焊40把左右。 现在焊接不用铜片,直接用铜丝焊。先用四氯化碳将刀杆焊接部分洗刷,将刀片放上,斜置成一定角度(图4),在刀杆头部加热,待加热後,将铜丝与硼砂同时加热。铜丝熔解後,…     

通用装配式车刀

<正> 机夹硬质合金可转位多边形刀片的装配式车刀与焊接式车刀比较有一系列优点,但是对于每种形式和尺寸的切削刀片都需要特定的刀杆,其刀槽也要与所用刀片的形状和尺寸精确地相符。为了减少可转位装配式刀具的品种与数量,苏联库尔干机械学院研制出一种附图所示的通用装配式车刀。它由可转位刀头1、可换刀座3、质合金支承片4、切削刀片5、钩形压板6、扇形齿板11和刀杆本体14等组成。刀座用螺钉2固定在刀头上,而刀座的形状须与支承     

焊接硬质合金车刀的经验

硬质合金车刀的焊接是比较困难的,这是由于刀头材料和刀杆材料(基本金属)的化学成分不相同的缘故。硬质合金刀头的导热性差,容易产生裂纹,并且不易粘得牢靠。所以我厂过去在焊接硬质合金车刀时,常常产生废品,并且很容易掉刀头。根据我们的研究,硬质合金车刀在焊接后掉刀头的原因有以下几点:1)我们用的焊料是黄铜,不合高速切削的要求,因为这种焊料在400℃以上的温度时,焊接强度会降低。2)焊接加热的温度及加热速度控制得不好;3)硬质合     

复合楔紧式可重磨硬质合金车刀

车刀是切削刀具中结构最简单，生产上应用最广的一种刀具。为了提高车刀的生产效率，提高刀杆的使用寿命，缩短调刀时间和使断屑稳定可靠，设计了多种刀交结构。本文介绍的复合楔紧式可重磨硬质合金率刀是其中较好的一种。一、车刀结构复合楔紧式可重磨硬质合金率刀见附图，由刀杆1，刀垫2，刀片8，断屑决4，调整螺钉5组成。它不用压板和紧固螺钉，而是在刀杆前端加工出楔形槽，在进行切削加工时，利用轴向切削分力和径向切削分为，使刀垫、刀片、断屑块三者组合体与刀杆楔形相产生一定弹性变形，从而靠摩擦力楔紧。为了保证刀片不会产生向…     

加工In718时硬质合金涂层刀具的磨损机理

采用硬质合金涂层刀具对镍基合金In718进行了车削试验,分析了硬质合金刀具的磨损形态、磨损机理,并给出了不同条件下的刀具寿命。结果表明,涂层硬质合金切削In718时的主要磨损形式为涂层剥落。     

A comparative study on performance of multilayer coated and uncoated carbide inserts when turning AISI D2 steel under dry environment

The present work deals with a comparative study on flank wear, surface roughness, tool life, volume of chip removal and economical feasibility in turning high carbon high chromium AISI D2 steel with multilayer MTCVD coated [TiN/TiCN/Al₂O₃/TiN] and uncoated carbide inserts under dry cutting environment. Higher micro hardness of TiN coated carbide samples (1880 HV) compared to uncoated carbide (1430 HV) is observed and depicts better resistance against abrasion. The low erosion rate was observed in TiN coated insert compared to uncoated carbide. The tool life of TiN coated insert is found to be approximately 30 times higher than the uncoated carbide insert under similar cutting conditions and produced lower surface roughness compared to uncoated carbide insert. The dominant wear mechanism was found to be abrasion and progression of wear was steady using multilayer TiN coated carbide insert. The developed regression model shows high determination coefficient i.e. R² = 0.977 for flank wear and 0.94 for surface roughness and accurately explains the relationship between the responses and the independent variable. The machining cost per part for uncoated carbide insert is found to be 10.5 times higher than the multilayer TiN coated carbide inserts. This indicates 90.5% cost savings using multilayer TiN coated inserts by the adoption of a cutting speed of 200 m/min coupled with a tool feed rate of 0.21 mm/rev and depth of cut of 0.4 mm. Thus, TiN coated carbide tools are capable of reducing machining costs and performs better than uncoated carbide inserts in machining D2 steel.     

硬质合金刀片CAD/CAM系统三维扫描测量输入技术

本文在综述了硬质合金刀片CAT/CAD/CAM一体化技术基础上,引进测量几何造型概念,详细介绍了硬质合金刀片扫描测量输入系统硬件及软件的设计特点,分析了一些特征扫描測量算法,最后给出了一个扫描测量实例。     

Experimental investigations on machinability aspects in finish hard turning of AISI 4340 steel using uncoated and multilayer coated carbide inserts

The present work deals with some machinability studies on flank wear, surface roughness, chip morphology and cutting forces in finish hard turning of AISI 4340 steel using uncoated and multilayer TiN and ZrCN coated carbide inserts at higher cutting speed range. The process has also been justified economically for its effective application in hard turning. Experimental results revealed that multilayer TiN/TiCN/Al₂O₃/TiN coated insert performed better than uncoated and TiN/TiCN/Al₂O₃/ZrCN coated carbide insert being steady growth of flank wear and surface roughness. The tool life for TiN and ZrCN coated carbide inserts was found to be approximately 19 min and 8 min at the extreme cutting conditions tested. Uncoated carbide insert used to cut hardened steel fractured prematurely. Abrasion, chipping and catastrophic failure are the principal wear mechanisms observed during machining. The turning forces (cutting force, thrust force and feed force) are observed to be lower using multilayer coated carbide insert in hard turning compared to uncoated carbide insert. From 1st and 2nd order regression model, 2nd order model explains about 98.3% and 86.3% of the variability of responses (flank wear and surface roughness) in predicting new observations compared to 1st order model and indicates the better fitting of the model with the data for multilayer TiN coated carbide insert. For ZrCN coated carbide insert, 2nd order flank wear model fits well compared to surface roughness model as observed from ANOVA study. The savings in machining costs using multilayer TiN coated insert is 93.4% compared to uncoated carbide and 40% to ZrCN coated carbide inserts respectively in hard machining taking flank wear criteria of 0.3 mm. This shows the economical feasibility of utilizing multilayer TiN coated carbide insert in finish hard turning.     

REDUCTION OF MACHINING VIBRATION BY USE OF RUBBER LAYERED LAMINATES BETWEEN TOOL HOLDER AND INSERT

The aim of the present study is to investigate chatter when using carbide inserts by measuring surface roughness of the workpiece. Dimensional accuracy of the workpiece is affected by vibration. In order to suppress chatter, the tool was provided with an ultra thin metal rubber laminate between the tool holder and insert. An experimental investigation has been carried out in CNC lathe using a “design of experiments” approach. In this study, vibration of the tool and surface roughness of the workpiece were measured. It has been observed that the vibration of the tool, as well as the tool insert, has been reduced by using ultra thin rubber layered laminates, and the surface finish of the workpiece has been improved.     

硬质合金圆柄止动槽成型刀设计

针对加工止动槽用硬质合金焊接刀刃磨时,其宽度难以控制、对刀困难、无法加工倒角等问题,设计了圆柄止动槽成型刀代替硬质合金焊接刀,只需刃磨排屑槽,节约了磨刀时间,保证了止动槽宽度尺寸,节省了倒角工序,提高可产品质量和经济效益。     

REDUCTION OF MACHINING VIBRATION BY USE OF RUBBER LAYERED LAMINATES BETWEEN TOOL HOLDER AND INSERT

The aim of the present study is to investigate chatter when using carbide inserts by measuring surface roughness of the workpiece. Dimensional accuracy of the workpiece is affected by vibration. In order to suppress chatter, the tool was provided with an ultra thin metal rubber laminate between the tool holder and insert. An experimental investigation has been carried out in CNC lathe using a “design of experiments” approach. In this study, vibration of the tool and surface roughness of the workpiece were measured. It has been observed that the vibration of the tool, as well as the tool insert, has been reduced by using ultra thin rubber layered laminates, and the surface finish of the workpiece has been improved.     

PCD刀具真空钎焊工艺研究

钎焊是刀具制作过程中的重要环节,焊接质量直接影响刀具连接强度。通过在真空环境中加热,以YG8硬质合金和PCD复合片为焊接母材进行钎焊试验。对比3种钎料在不同焊接温度和保温时间下钎料润湿性和焊接强度的变化,确定3种钎料的最佳焊接参数及适用范围,并分析了阻流剂的使用对钎料阻流的效果,试验表明,使用阻流剂能有效控制钎料溢流至非焊接面。     

铣削粉末冶金高温合金的刀具优选试验

针对粉末冶金高温合金材料的铣削特性,选择了合理的刀片材质。通过刀具磨损与寿命对比试验,优选出了最佳的刀片牌号及几何参数。研究结果表明:SECO SEMX1505AFTN-MD20-F30M涂层硬质合金刀片适用于铣削粉末冶金高温合金,并对涂层硬质合金刀具前、后刀面的磨损形貌和失效机理进行了分析。     

一种新型工具钢冷焊焊缝的研究

利用扫描电镜 (SEM)、透射电镜 (TEM)及X射线衍射等方法研究了一种新型工具钢冷焊焊缝的微观组织 ,认为加入强碳化物元素可获得在低碳马氏体基体上弥散分布碳化物颗粒的冷焊焊缝 ,该焊缝硬度高、韧性好 ,可同时满足工具钢对耐磨性和抗裂性的要求