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四大材料刀具的性能与选择刀具材料的发展对切削技术的进步起着决定性的作用。
本文介绍了切削中所使用的金刚石、聚晶立方氮化硼、陶瓷、硬质合金、高速钢等刀具材料的性能及适用范围。
刀具损坏机理是刀具材料合理选用的理论基础，刀具材料与工件材料的性能匹配合理是切削刀具材料选择的关键依据，要根据刀具材料与工件材料的力学、物理和化学性能选择刀具材料，才能获得良好的切削效果。
就活塞在切削加工时的刀具材料选用作了阐述。
高速钢：活塞加工中铣浇冒口、铣横槽及铣膨胀槽用铣刀，钻油孔用钻头等都为高速钢材料。
硬质合金：YG、YD系列硬质合金刀具被广泛应用于铝活塞加工的各个工序中，特别是活塞粗加工和半精加工工序。
立方氮化硼：立方氮化硼刀具被用于镶铸铁环活塞的车削铸铁环槽工序中。
同时也应用于活塞立体靠模的加工中。
金刚石：金刚石刀具可利用金刚石材料的高硬度、高耐磨性、高导热性及低摩擦系数实现有色金属及耐磨非金属材料的高精度、高效率、高稳定性和高表面光洁度加工。
在切削铝合金时，PCD刀具的寿命是硬质合金刀具的几十倍甚至几百倍，是目前铝活塞精密加工的理想刀具，已经应用于精车活塞环槽、精镗活塞销孔、精车活塞外圆、精车活塞顶面及精车活塞燃烧室等精加工工序中。
刀具材料性能的优劣是影响加工表面质量、切削加工效率、刀具寿命的基本因素。
切削加工时，直接担负切削工作的是刀具的切削部分。
刀具切削性能的好坏大多取决于构成刀具切削部分的材料、切削部分的几何参数及刀具结构的选择和设计是否合理。
切削加工生产率和刀具耐用度的高低、刀具消耗和加工成本的多少、加工精度和表面质量的优劣等等，在很大程度上都取决于刀具材料的合理选择。
正确选择刀具材料是设计和选用刀具的重要内容之一。
每一品种刀具材料都有其特定的加工范围，只能适用于一定的工件材料和切削速度范围。
不同的刀具材料和同种刀具加工不同的工件材料时刀具寿命往往存在很大的差别，例如：加工铝活塞时，金刚石刀具的寿命是YG类硬质合金刀具寿命的几倍到几十倍；YG类硬质合金刀具加工含硅量高、中、低的铝合金时其寿命也有很大的差别。
数控加工中切削用量的合理选择【摘要】文章介绍了切削用量的三要素，并对数控机床加工时切削用量的合理选择进行了详细阐述，为数控机床编程与操作人员提供参考。
关键词】切削用量；加工质量；刀具耐用度；选择原则前言：数控加工中切削用量的原则是，粗加工时，一般以提高生产率为主，但也应考虑经济和加工成本；半精加工和精加工时，应在保证加工质量的前提下，兼顾切削效率、经济性和加工成本。
具体数值应根据机床说明书、切削用量手册，并结合经验而定。
切削用量是表示机床主运动和进给运动大小的重要参数。
切削用量的确定是数控加工工艺中的重要内容，切削用量的大小对加工效率、加工质量、刀具磨损和加工成本均有显著影响一、切削用量的选择原则数控加工中选择切削用量，就是在保证加工质量和刀具耐用度的前提下，充分发挥机床性能和刀具切削性能，使切削效率最高，加工成本最低。
（一）加工质量：加工质量分为加工精度和加工表面质量。
1•加工精度是指零件加工后实际几何参数（尺寸、形状和位置）与理想几何参数相符的程度。
符合程度愈高，加工精度愈高。
实际值与理想值之差称为加工误差，所谓保证加工精度，即指控制加工误差。
⑴尺寸精度：加工表面的实际尺寸与设计尺寸的尺寸误差不超过一定的尺寸公差范围。
在国标中尺寸公差分20级（IT01、ITO、IT1〜IT18 ）。
尺寸精度的获得方法：①试切法：试切一一测量一一调整一一再试切。
用于单件小批生产。
②调整法：通过预调好的机床、夹具、刀具、工件，在加工中自行获得尺寸精度。
用于成批大量生产。
③尺寸刀具法：用一定形状和尺寸的刀具加工获得。
生产率高，但刀具制造复杂。
④自动控制法：用一定装置，边加工边自动测量控制加工。
切削测量补偿调整。
⑵几何形状精度：加工表面的实际几何要素对理想几何要素的变动量不超过一定公差范围。
在国标中形状公差有六项：直线度、平面度、圆度、圆柱度、线轮廓度、面轮廓度。
几何形状精度的获得方法：成形运动法①轨迹法：利用刀具与工件间的相对运动轨迹来获得形状。
卧式数控车床切削用量选择作者：杨树诚单位：沈阳第一机床厂技术部日期：2005年09月本文着重提醒读者1.不要轻易按刀具样本的推荐值确定切削速度，那样刀具寿命很低。
一般情况下，硬质合金刀片可按刀具样本推荐值的0.64～0.71倍选择切削速度。
2.确定精加工和半精加工的进给量着眼于工件的表面粗糙度。
它还和刀尖半径有关。
文中列表表明三者对应关系，供选择进给量参考。
3.条件允许时希望粗加工吃刀深尽量大。
一方面有效提高生产率；一方面也为了消除表面硬皮.切除砂眼等缺陷，从而保护刀尖不与毛坯接触。
精加工时也不希望吃刀深太小，以免产生刮擦对粗糙度不利。
4.表5～表12列举了外圆.端面.内孔加工，切槽，车螺纹的切削用量推荐值。
供一般情况下采用。
目录一.原始资料 (1)二.选择切削用量的原则 (1)三.吃刀深αp (2)四.进给量f (2)五.切削速度V (4)六.切削用量推荐值 (5)切削用量选择关键词: 刀具耐用度 切削速度 表面粗糙度 进给量 吃刀深在售前服务编制加工工序卡以及调装设计中，都需要确定切削用量及计算节拍时间。
本文就卧式数控车床如何合理选择切削用量进行探讨。
一. 原始资料：无论编制加工工序卡－即制定工艺方案还是调装设计都需要掌握以下资 料，做为刀具选择.卡具设计以及选择切削用量的依据。
.1 工件图：包括形状.尺寸.公差.形位公差.粗糙度和其他技术要求。
特别强调的是本序 加工的部位必须明确，用于及可能影响装卡部位的形状要表示清楚。
2.毛坯图：毛坯形状.尺寸，加工余量，材料.硬度等。
3.生产纲领：即年产量或单件时间，这对招标项目尤为重要。
4.验收要求：机床验收时对工件考核什麽项目，有无Cp 值和其它要求。
5.用户对工件定位基准.卡紧面.辅助支承 等要求，或指定参考的卡具样式。
6. 对刀具选择要求：用国产刀具或国外指定厂家 的刀具，特殊刀具是否自备等。
7. 用户单位，件名.件号等也应标明，以便管理。
二 选择切削用量的原则：1. 总的要求：保证安全，不致发生人身事故或设备事故；保证加工质量。
数控车床切削用量的选用原则在数控车床的加工过程中，切削用量的选用对于加工质量和效率起着重要的影响。
合理的切削用量选用不仅可以提高加工精度和表面质量，还能延长刀具寿命和减少加工成本。
本文将介绍数控车床切削用量选用的原则，以帮助读者正确进行数控车床的切削加工。
1. 根据加工材料选用合适的切削用量不同材料具有不同的切削性能，因此在加工过程中应根据材料的硬度、韧性、塑性等特性来选用合适的切削用量。
对于硬度较高的材料，如铸铁、合金钢等，应选用较小的切削用量，以减少切削阻力和热量积累，降低刀具磨损。
而对于韧性较高的材料，如铝合金、铜等，可以适当增大切削用量，以提高加工效率。
2. 根据切削类型选用合适的切削用量切削类型包括粗加工和精加工两种，对应的切削用量也有所不同。
在粗加工中，为了快速去除材料，可以适当增大切削用量，提高进给速度和切削深度，以达到较高的加工效率。
而在精加工中，要求加工精度和表面质量较高，需要减小切削用量，降低进给速度和切削深度，以提高加工精度。
3. 根据刀具类型选用合适的切削用量不同的刀具具有不同的切削特性，根据刀具的类型和材质选用合适的切削用量非常重要。
例如，对于硬质合金刀具，其硬度较高，可以承受较大的切削力，因此可以选用较大的切削用量，提高加工效率。
而对于高速钢刀具，其硬度较低，需要减小切削用量，以避免过大的切削力导致刀具断裂。
4. 根据加工要求选用合适的切削用量不同的加工要求需要选用不同的切削用量。
例如，对于外表面加工，为了保证表面质量，应选用较小的切削用量，减小表面粗糙度。
而对于内孔加工，为了保证加工精度，可以适当增大切削用量，提高加工效率。
此外，还需要考虑到加工后的余量，选用合适的切削用量，以便进行后续的修整和调整。
总结起来，数控车床切削用量的选用原则包括根据加工材料、切削类型、刀具类型和加工要求来选择合适的切削用量。
合理选用切削用量不仅能提高加工效率和质量，还能延长刀具寿命和降低加工成本。
钻孔加工五大关键问题钻头作为孔加工中常见的刀具，被广泛应用于机械制造中，特别是对于冷却装置、发电设备的管板和蒸汽发生器等零件孔的加工等，应用面尤为广泛和紧要。
一、钻削的特点钻头通常有两个主切削刃，加工时，钻头在回转的同时进行切削。
钻头的前角由中心轴线至外缘越来越大，越接近外圆部分钻头的切削速度越高，向中心切削速度递减，钻头的旋转中心切削速度为零。
钻头的横刃位于回转中心轴线相近，横刃的副前角较大，无容屑空间，切削速度低，因而会产生较大的轴向抗力。
假如将横刃刃口修磨成DIN1414中的A型或C型，中心轴线相近的切削刃为正前角，则可减小切削抗力，显著提高切削性能。
依据工件形状、材料、结构、功能等的不同，钻头可分为很多种类，例如高速钢钻头（麻花钻、群钻、扁钻）、整体硬质合金钻头、可转位浅孔钻、深孔钻、套料钻和可换头钻头等。
二、断屑与排屑钻头的切削是在空间狭窄的孔中进行，切屑必需经钻头刃沟排出，因此切屑形状对钻头的切削性能影响很大。
常见的切屑形状有片状屑、管状屑、针状屑、锥形螺旋屑、带状屑、扇形屑、粉状屑等。
钻削加工的关键——切屑掌控当切屑形状不适当时，将产生以下问题：①细小切屑堵塞刃沟，影响钻孔精度，降低钻头寿命，甚至使钻头折断（如粉状屑、扇形屑等）。
②长切屑缠绕钻头，拦阻作业，引起钻头折损或阻拦切削液进入孔内（如螺旋屑、带状屑等）。
如何解决切屑形状不适当的问题：①可分别或联合接受增大进给量、断续进给、修磨横刃、装断屑器等方法改善断屑和排屑效果，除去因切屑引起的问题。
②可使用专业的断屑钻头打孔。
例如：在钻头的沟槽中加添设计的断屑刃将切屑打断成为更简单清除的碎屑。
碎屑顺畅地沿着沟槽排出，不会发生在沟槽内堵塞的现象。
因而新型断屑钻获得了比传统钻头流畅很多的切削效果。
同时短碎的铁屑使冷却液更简单流至钻尖，进一步改善了加工过程中的散热效果和切削性能。
而且由于新增的断屑刃穿了钻头的整个沟槽，经过多次修磨之后仍旧能够保持其形状和功能。
加工材料钻头直径(ød)切削速度V(m/min)进给量f(mm/r)进给速度F(mm/min)加工材料钻头直径(ød)切削速度V(m/min)进给量f(mm/r)进给速度F(mm/min) 623.60.11251075.40.15360 825.50.121221589.50.18342 1025.10.1411220103.60.22363 15260.189925117.80.25375 2025.50.2289301130.28336 25240.2576351040.3285 30220.286540100.50.33264 35200.35540190.35531062.80.2400 45170.42501584.80.22396 60150.5402094.20.25375251020.28364 620.70.151653094.20.3300 823.90.21903593.40.33280 1023.60.261954087.90.35245 1525.90.321762025.10.381522527.50.421473026.40.481343519.80.529440150.55664514.10.6606014.10.65492. 对孔的精度要求较高或孔表面粗糙度要求较高时，内冷充分冷却。
高速钢钻头的切削用量(推荐值)铸铁(HB120～225）硬质合金钻头的切削用量(推荐值)碳素结构钢和优质碳素结构钢(HB125～225）铸铁(HB120～225）注：1. 以上切削参数使用条件：孔深=3ød；硬质合金钻头 可适当提高转速，降低进给量。
碳素结构钢和优质碳素结构钢(HB125～225）钻头直径mm 15φ< 30~15φφ< 50~30φφ<进给量 mm/r0.05~0.15 0.15~0.25 0.20~0.30硬质合金钻头线速度 min /120~100m =ν高速钢钻头(HSS) 1> Q235-A min /30m =ν 2> 16Mn min /20m =ν切削速度ν：刀类相对于工件的线速度转速即圆周长ו•=n d πν高速钢钻头线速度：min /03~25m =ν进给量（吃刀量）mm/r 钻头每转一转走的长度（轴向），取：0.2mm/r（齿数）刃Z /×mm 取0.1~0.2 mm/刃硬质合金钻头线速度min /120~100m =ν孔的精度：孔径公差；孔的表面光洁度 钻孔精度：孔距公差；孔的垂直度THE TWIST DRILLSThe twist drill is the more simple tool for drilling holes cylindrical, usually from solid.The twist drill is formed by:x by a cylindrical or conical shank to center on the spindle of the machine and transmit the cutting torque (by friction or drag tooth)x by a cylindrical part in which are carried two opposing helical grooves, which intersect with surface ends form the two main cutting edges.The two helical grooves allow the evacuation of the chip that is formed at the cutting edges, and lead near the same, the lubricating/coolant fluid .Characteristic elements of endsThe check or driving surfaces (with rake angle lower by about 2°) are formed by two off-set diametrically opposed to the limit of the helical grooves and have a dual function: à driving the tip into the hole without even the jam during drilling, because thecontact between the drill and sides of the hole is limited.à finishing the cylindrical surface of the hole.The central core (central scraping edge) between the two grooves has a diameter (0.1~0.2) × D and provides to give the torsional strength to the drill during machining. However for a hole made by a twist drill we can be obtained the maximum standard ofIT 10 and a roughness Ra> 1.8 mm, which often must be finished with other processes such as boring or grinding.Caracteristic anglesİ :Inclination angle of helix .It is formed ythe tangent of the helix average with axisof the drill. Its value is so smaller as harderSEZ N-Nis the material to machining.ij:Angle of cutters. It is the angle formedby the two main cutter.Ȗ:Upper rake angleȕ:Cutting angleĮ:Lower rake angleThe characteristic angles can assume different values in according to the material to be machined and the diameter of the drill.WORKING CONDITIONS IN DRILLINGRelative motion and cutting parametersThe main relative motions are the motion of cutting and the move of advance or feed. The motion of cutting is the main motion of the machine, and is what determines the removal of chip.On the drilling machine it is rotating type and is acted by the tool.The motion of cutting can be expressed both as cuttingspeed, both as rotary speed.The cutting speed, denoted by V (m / min), represents therelative speed between tool and workpiece, at the pointwhere it be removed the chip, therefore the speedwherewith the material can be cut.It is equivalent to peripheral speed of the tool, that is thespeed of point P shown in the figure, which is tangent tothe circle of point P in same sense of rotation. The cuttingspeed is not constant along all points of the cutting edge,but varies from a maximum (cutting speed rated) at thepoint P to a zero value at the axis of the tool.The value set depends on: material processing, material ofthe tool and diameter of the drill.There are tables indicating the value needed depending onworking conditions.The cutting speed and the speed of rotation are related by:This relation calculates the number of rounds to select on the drilling machine, after determining the cutting speed more suitable for processing.The movement of advance or feed aims to bring new material from the tool contact. It is a movement much slower than the motion of cutting.On drilling machine it is a translational motion and is impressed to the tool, according to its axis, in a continuous and simultaneous movement of the cutting.The movement forward can be expressed as feed per revolution, both as speed of advancement.Advancement per revolution, indicated by a (mm / rev), representing the movement of the tool for every lap completed by the same tool.Its value depends on the diameter and material of tool, as well as the material processing. For the selection of the advanced exist tables that suggest the value needed depending on conditions of work.Speed of advancement, indicated by Va (mm / min), represents the speed with which the tool moves, hence the speed with which the processing proceeds.The two magnitude are related by the following relation:Indeed, if a indicates the tool displacement per revolution, multiplying its the number for the revolutions n made in a minute, you get the movement of the tool for each minutes; that is its speed of advancement.SECTION OF THE CHIPThe section of the chip, denoted by q, in the case of a twist drill,takes the form of a parallelogram equivalent to a rectangle ofheight equal to half of the feed per revolution and a basis equalto the radius of the drill. (D / 2 represents the depth of cut in thecase of drilling a hole from solid).Indeed, if for every round of the drill advances of a step equal to a(advancement per revolution), each of cutters to remove a chipwith a side a / 2.In this case, the section area of the chip removed from each edge is:Cutting forceCutting forces required on both edges of the twist drill to detach the chip depend :x from material of workpiece, through the load or pressure to tear Ks (N/mm2).x from total chip section Q = 2 x q (mm 2) detached from the tool.These forces, one for each main cutting edge, supposedly applied approximately half the length of the cutting edge.Each of them takes the value:section of one cutter chipthere is a cutting force :withThen foreach cutterOn average it is considered that : xKs = (4,2 y 5) Rm for cast ironwitch Rm the diameter of drill nd with higher values he total cutting force is :x Ks = (4,8 y 6) Rm for steels and non-ferrous materials In is strength of the material in N/mms decreases with increasing of the advanced. However keep in mind that the value of K a TCUTTING POWERcreate a torque (cutting moment). with dimension b in metres.Looking where the cutting forces are positioned you can see that they form a couple of forces that The value is:aller values forrittle materials (cast iron), higher values for lasting materials (steel).sional stress, where the torque is equal and opposite to the utting moment.sics we know that in rotary motion, the power is calculated using the followinglation:The value of arm b is assumed, the approximate equivalent to D / 2, but in reality its value varies with the type of material that is drilled. In particular b = (0.45÷ 0.60) × D : sm b The tool is subject to a tor c From phyre Where M is sum of torques applied to the body respect to its axis of rotation. nd Ȧ is the angular velocity of the body. the case of drilling:xM represents the moment of cutting forces, then as we saw earlier.with dimension b in metresxȦ is the angular velocity of twist drills.with n number of rounds of the drill ino the cutting power is:aInSWhereand :he power required for the advancement of twist drills can be neglected, because little. tearing of the chip, but also all the sses may be present in transmission of motion.o account for this power dissipation introduces the mechanical efficiency: echanical efficiencyom which flows: T So that the processing is possible, the engine power of the drill must be capable of winning not only the moment of resistance due to lo T m fr that allows us to calculate the engine outputen we known the effective power of cutting and the mechanical efficiency of the achine.he mechanical efficiencyȘ depends on the state of the machine: h = 0.6 ¸ 0.8. power, wh m T It has the condition of maximum utilization of the drilling machine when the power eveloped by its motor c Working timedoincides with the available power of the engine.The relation that calculates the working time is the following:he tool, is With reference to the figure we see that the travel,that is the distance that who must run t e sum of four quantities, namely:th L is the depth of the holee 1 is the overtravel attack : e 1 = 1÷ 2 mm e 2 is the overtravel output : e 2 = 1 2 mml p is the height of the drill cone : l p = ~ 0.33 × DRegarding the height of th edges, with the following considerations of trigonometry.angle OAB is noted that:e drill cone, the approximate value lp = ~ 0.33 × D, can bereplaced by the correct value function of the cuttingFrom the tri from the definition of tangent:which is calculated:For example in the case of a twist drillø 20 for drilling steel with Rm <700 N/mm2 withngle of the cutting edges M = 118 ° is calculated:aE XEMPLEecessary power and time to drill a trough hole ( Tool in high speed steel ) eatures:nd N/mm 2Mechanical efficiency Ș = 0,75alculation of poweralculation of working timeel with Rm <700 N/mm2 and with angle of thecutting edges M = 118°, it is calculated:N F Hole diameter D = 16 mm Hole deep L = 25 mm Feed a = 0,2 mm/rou Cutting speed V = 32 m/min Material strength Rm = 600C We can assume:We think to can select exactly this speed on drilling machineCutting powerOutput power of motorC If we use a twist drillø 20 for drilling ste We assume。
