CVD金刚石涂层工艺对硬质合金立铣刀铣削CFRP性能的影响

传统硬质合金刀具铣削碳纤维复合材料（CFRP）时磨损严重,需在其上沉积金刚石薄膜涂层。在相同的硬质合金立铣刀基体上,改变沉积工艺,获得3种分别覆有粗晶、细晶和复合晶等不同CVD金刚石薄膜的刀具。用扫描电镜观察分析3种涂层的表面形貌。在相同条件下,用3种刀具切削CFRP并分析其刀具磨损机理。结果表明:复合晶工艺的金刚石涂层硬质合金立铣刀耐磨性最好、使用寿命最长,约为粗晶金刚石涂层铣刀的1.35倍、细晶金刚石涂层铣刀的1.59倍,更适合于CFRP材料的铣削加工。      

超声振动铣削碳纤维复合材料刀具磨损研究

介绍了采用超声振动铣削和普通铣削对硬质合金铣刀铣削碳纤维复合材料进行试验研究。试验结果表明,在两种加工方式下,刀具的磨损形式主要是后刀面磨损,前刀面磨损和刀刃的破损,其中后刀面的磨粒磨损最严重,前刀面的粘着磨损较弱,当进给量加大或者是主轴转速过高时,很容易发生崩刃。超声振动条件下,刀具的后刀面磨损和前刀面磨损均较弱,且呈现一定的规律性。刀具的耐用度高,相对于普通切削更适合于复合材料的加工。     

淬硬钢（≥60HRC）的高速加工

用立铣刀切削加工淬硬钢时,切削深度和每齿进给量的增加将引起切削阻力显著增大,因此,在小切深且不增加每齿进给量的条件下,采用高速铣削这种高效加工方法十分有效。但是,随着被加工工件硬度的提高,切削热也在增加,使刀具刃口处于高温状态。这样,由于扩散和氧化等原因,将加剧刀具的磨损。因此,用于高速铣削淬硬钢的刀具,在高温下的稳定性显得十分重要。     

加工石墨电极用金刚石涂层球头立铣刀

石墨电极可用立铣刀进行加工。但由于电极材料硬度极高,使立铣刀的刀尖磨损很快,因此难以实现高效铣削加工。为了提高立铣刀的耐磨性能,Union Tool公司与旭金刚石工业公司合作开发了用于加工石墨电极的金刚石涂层立铣刀,大幅度提高了金刚石涂层与硬质合金基体的结合强度。     

碳纤维/树脂基复合材料高速铣削的刀具磨损机理

采用涂层(Ti CN,Ti Al N)与无涂层超细晶粒硬质合金立铣刀对碳纤维/树脂基复合材料进行高速铣削试验,研究了刀具后刀面磨损带扩展及刀具磨损规律,并探讨了切削力、毛刺随着刀具磨损的变化趋势,观察了刀具的微观磨损形貌,分析了刀具的磨损机理。结果表明:在相同的切削条件下,无涂层刀具的后刀面磨损量及切削力最大,毛刺扩展严重,后刀面主要发生磨粒磨损,由于黏着磨损和氧化磨损对切削刃的弱化作用,主切削刃发生了微崩刃;Ti CN涂层刀具后刀面主要发生磨粒磨损,并伴随有黏着磨损和轻微的氧化磨损,失效形式为剥落和微崩刃;Ti Al N涂层刀具的后刀面磨损量及切削力最小,毛刺扩展缓慢,更适合碳纤维复合材料的加工。其后刀面主要发生了磨粒磨损,其失效形式为剥落。     

新型立铣刀高速铣削碳纤维复合材料试验研究北大核心

针对碳纤维复合材料精密加工极易产生毛刺等缺陷,选用新型四刃粗精交错刃结构的立铣刀和常规硬质合金立铣刀,在相同条件下对纤维方向角为45°、90°、135°的碳纤维复合材料进行高速铣削对比试验。通过对比分析毛刺因子、铣削轴向力、表面粗糙度、表面微观形貌及毛刺抑制机制得出:新型粗精交错立铣刀与常规硬质合金立铣刀加工相比,工件侧表面的毛刺长度及数量均得到显著的改善;各纤维方向角铣削力Fz平均值依次下降20.93%、17.74%和5.78%;纤维方向角θ为45°和90°时面粗糙度较好满足加工要求,而纤维方向角135°的表面粗糙度均急剧增加超出合格标准。总体而言,新型粗精交错立铣刀切削能有效抑制毛刺的生成,且保证加工表面粗糙度不发生剧变,因此更适合应用于碳纤维复合材料高速铣削加工。     

Union Tool公司与旭金刚石工业公司合作开发用于加工石墨电极的金刚石涂层立铣刀

石墨电极可用立铣刀进行加工,但由于电极材料硬度极高,使立铣刀的刀尖磨损很快,因此难以实现高效铣削加工。为了提高立铣刀的耐磨性能,UnionTool公司与旭金刚石工业公司合作开发了用于加工石墨电报的金刚石涂层立铣刀,大幅度提高了金刚石涂层与硬质合金基体的结合强度。通过提供给部分用户试用,其铣削石墨电极的性能获得了用户高度评价,现已作为标准产品上市销售。     

山特维克可乐满将推出新型iLock夹持系统

山特维克可乐满将推出新型iLock夹持系统,用于ISOS材料的铣削。使用整体硬质合金立铣刀加工高温合金材料时所产生的轴向力对刀具的夹紧机构提出了很高的要求。在实际切削加工中,即使已经施     

工具的材料和涂层对其切削性能的影响

对同种材料不同涂层和不同材料同种涂层的刀具进行了切削试验。结果表明,在铣削淬硬的40Cr钢时,用硬质合金A制作、带TiAlCN涂层的6刃立铣刀使用寿命最高。这既与涂层的耐磨性、表面粗糙度和抗氧化性能有关,也与硬质合金A的硬度、韧性和抗弯强度有关。     

交流磁化处理对硬质合金刀具切削性能的影响

为研究交流磁场对硬质合金刀具切削性能的影响,对YT5刀具进行磁场强化处理,通过正常工况下铣削不同磁属性材料,从铣削力、刀具摩擦磨损和工件表面质量3个方面分析了磁场影响规律。运用Kistler-9257B动态压电式测力仪测量铣削力的变化,并在扫描电镜(SEM)上观察了刀具的磨损形貌。结果表明,磁场强化处理对硬质合金铣刀加工铁磁性材料的工件表面质量具有优化作用,磁化处理减小了刀具的磨损,增大了切削力,工件表面质量有所提高。加工顺磁性材料时,铣刀的磨损减少,切削力基本不变,工件表面质量无明显提高。     

Cutting performance of PVD-coated carbide and CBN tools in hardmilling

In this study, cutting performance of CBN tools and PVD-coated carbide tools in end-milling of hardened steel was investigated. In high-speed dry hardmilling, two types of CBN tools were applied: the CBN-rich type and an ordinary one. In the case of relatively low-speed milling, on the other hand, a few coated carbide tools were selected where four kinds of coating films, TiN, TiCN, TiAlN and multi-layered TiAlN/AlCrN, were deposited on the K10 and P30 grade carbide. The cutting performance was mainly evaluated by tool wear, cutting temperature, cutting force and surface roughness. In dry cutting of hardened carbon steel with the ordinary CBN tool, the cutting tool temperature rose rapidly with increase in cutting speed; and tool temperature reached approximately 850 °C at the cutting speed of 600 m/min. In the case of the CBN-rich tool, the cutting temperature decreased by 50 °C or more because of its high thermal conductivity. It is remarkable that tool wear or damage on a cutting tool was not observed even when the cutting length was 156 m in both CBN tools. In the case of coated carbide tools, the temperatures of TiN-, TiCN- and TiAlN-coated carbide tools rose as cutting proceeded because of the progress of tool wear, but that of TiAlN/AlCrN-coated carbide tool hardly rose due to little tool wear. When the base material was K10 grade carbide, tool temperature was lower than that of P30 with any coating. The tool flank wear depends considerably on hardness and oxidizing temperature of the coating film.     

Tool life and tool wear in the semi-finish milling of inclined surfaces

Functional die and mold components have complex geometries and are made of high hardness materials, which make them difficult to machine. This work contributes to a better understanding of this type of process and of the wear mechanisms of tools used in semi-finishing operations of hardened steels for dies and molds. Several milling experiments were carried out to cut AISI H13 steel with 50 HR_C of hardness using the high-speed milling technique. The main goal was to verify the influence of workpiece surface inclination and cutting conditions on tool life and tool wear mechanisms. The main conclusions were the inclination of the machined surface strongly influences tool life and tool wear involves different mechanisms. At the beginning of tool life, the wear was caused mainly by abrasion on the flank face plus diffusion and attrition on the rake face. At the end of tool life, the mechanisms were adhesions and microchipping at the cutting edge.     

Development of new ceramic cutting tools with alumina coated carbide powders

An experimental investigation is carried out to coat two types of carbide powders, TiC and (W, Ti)C, with an alumina ceramic using a sol-gel technology. The coated carbide powders are then fabricated into two kinds of new ceramic tool materials by the hot pressing method. A scanning electron microscope (SEM) observation reveals that in general the matrix (carbide) grains are uniformly coated with the alumina ceramic and the microstructure of the new tool materials is more homogeneous than that of conventionally made ceramics. The tests of mechanical properties and wear resistance in machining are finally conducted. It is shown that when machining a mild carbon steel the new tool materials can increase the tool-life by up to 100% as compared to other two ceramic tool materials that have the same matrix but fabricated in the conventional way, while the fracture toughness is improved by up to 33%. When compared with a hard coated carbide tool, the new materials exhibit a superior ability in maintaining the wear resistance during the entire tool-life.     

碳纤维增强复合材料成型槽铣削的试验研究

碳纤维增强复合材料（CFRP）属于典型的难加工材料。通过改变加工工艺参数,使用硬质合金成型铣刀,研究了碳纤维复合材料成型槽铣削时铣削力随铣削速度和进给速度的变化关系,并分析了铣削出口表面的加工缺陷及其与铣削力的变化关系。试验结果表明：铣削力随铣削速度的升高而降低,随进给量的增大而减小;铣削出口处表面主要缺陷为撕裂、毛刺和材料未切断等,其中撕裂为主要缺陷且撕裂面积随铣削力的变大而增大。     

喷丸强化用高铬铸铁抛丸机叶片失效分析

对从美国进口的 2 W/ A抛丸机所用的四种高铬铸铁叶片进行了失效分析。结果表明 :叶片因冲蚀磨损而失效 ;基体材料主要是由于变形反复挤压后断裂流失 ,而碳化物主要是由于裂纹萌生扩展后断裂流失 ;进口叶片性能优良的主要原因是 :1碳化物垂直磨面定向排列 ,2基体硬度高 ,3碳化物尺寸较大 ,4没有一次碳化物     

低碳钢搅拌摩擦焊用摩擦头的失效研究

选用YG8硬质合金作为摩擦头材料进行低碳钢的搅拌摩擦焊试验。采用游标卡尺测量工具、X射线衍射仪和能谱仪等分析摩擦头在焊接过程中的主要失效形式。结果表明,YG8硬质合金摩擦头在低碳钢的搅拌摩擦焊过程中的主要失效形式为机械磨损、氧化剥落、搅拌针脆性断裂和轴肩变形失效等。引起失效的主要原因是摩擦头长时间的高温高压摩擦,导致粘结相Co分布不均匀或部分扩散流失,严重破坏了硬质合金的骨架模型;失效后摩擦头组织中出现了游离碳和硬脆相Co6W6C,减弱粘结相Co对基体相碳化钨的固溶强化作用,最终导致摩擦头的硬度、强度和耐磨性等下降。     

Experimental investigation on hard milling of high strength steel using PVD-AlTiN coated cemented carbide tool

High strength steel 30Cr3SiNiMoVA (30Cr3) is usually used to manufacture the key parts in aviation industry owing to its outstanding mechanical properties. However, 30Cr3 has poor machinability due to its high strength and high hardness. Hard milling is an efficient way in machining high strength steels. This paper investigated hard milling of 30Cr3 using a PVD-AlTiN coated cemented carbide tool with regard to cutting forces, surface roughness, chip formation and tool wear, respectively. The experimental results indicated that the increase of cutting speed from 70 to 110 m/min leads to direct reduction of cutting forces and improvement of surface finish, while both feed rate and depth of cut have negative effect on surface finish. The occurrence of oxidation on chip surfaces under high cutting temperature makes the chips show different colors which are strongly influenced by cutting speed. Saw-toothed chips were observed with the occurrence of the thermo-plastic instability within the primary shear zone. Micro-chipping and coating peeling were confirmed to be the primary tool failure modes. Serious abrasion wear and adhesive wear with some oxidative wear were confimed to be the main wear mode in hard milling of 30Cr3.     

钢结硬质合金的磨料磨损耐磨性

对五种不同成分的钢结硬质合金的磨粉磨损耐磨性在两种不同的磨损条件下进行了系统地研究，分析了各种钢结硬质合金的显微组织，并测定了它们的整体宏观硬度。试验结果表明，钢结硬质合金中碳化物的种类、含量以及钢基体的组织和硬度对其耐磨性均有着显著的影响。碳化物和钢基体的硬度越高以及碳化物的体积分数越大，则钢结硬质合金的耐磨性也越高，工具钢结硬质合金的耐磨性明显高于高锰钢结硬质合金的耐磨性。