硬质合金可调节浮动铰刀

该产品是一种孔加工刀具,用于切削加工各种金属工件。 其特点在于将硬质合金刀头的各个刀刃面磨至镜面,其表面粗糙度达到Rα<0.02μm(▽13～▽14),而刀刃部十分锋利     

轴向车铣表面形貌的计算机仿真

对轴向车铣加工进行数学建模,建立其表面形貌的计算机仿真系统,并利用该系统探讨了刀具工件转速比、刀具尺寸、刀刃数、进给速度和切深等参数对被加工件表面形貌的影响,得到以下结论:刀具与工件转速比越大,刀具尺寸越大,表面形貌越平坦,表面粗糙度越小;用六刃以上的铣刀进行车铣加工,能得到较小的表面粗糙度和较好表面微观形貌;随着进给速度的增大,表面粗糙度总体上趋于上升,但中间有起伏;切削深度对表面粗糙度和表面微观形貌的影响很小.     

通用镶片铣刀的力学和动力学

在粗、精加工零件时,广泛使用镶片铣刀.实际应用中刀片的几何形状和刀片在刀体上的分布非常重要.为了预断铣削时的切削力、振动、表面粗糙度和稳定性图,文章介绍镶片铣刀广义数学模型.在该文中,刀刃几何被每一刀片的局部坐标系所定义,它在刀体上的定位和定向使用刀具总坐标系.刀刃的位置被数学定义,并用来预断沿切削区的切削厚度分布.用求解每一切削处切削的力学和动力学,并在整个切削区积分,可以预断出任何镶片铣刀的铣削过程.预断和试验结果相当一致.     

伊斯卡涂层涂装技术在市场竞争中脱颖而出

切削刀具的基底、涂层和刀刃的准备,在高效加工中起着关键的作用,经常关乎金属切削工序的成败。这些因素,加上嵌入的断屑器和刀尖,决定着切削刀具对于一个特定的工件或特定的用途的适应性。     

新型Ta-C涂层铣刀切削性能研究

目的研究Ta-C涂层刀具与普通类金刚石涂层刀具切削2A50铝合金时的性能对比。方法通过实验比较两刃、四刃Ta-C涂层铣刀和两刃、四刃普通类金刚石涂层铣刀,在干式切削条件下切削2A50铝合金的性能。通过相同切削条件下刀具切削距离的长短,比较刀具的使用寿命,并在显微镜下观察切屑的表面形貌,用表面粗糙度仪检测铝合金表面的粗糙度。结果两刃Ta-C涂层铣刀干式切削铝合金时的使用寿命最长,切削距离为116 m。Ta-C涂层铣刀与普通类金刚石涂层铣刀加工工件的表面粗糙度总体呈上升趋势,两刃Ta-C涂层铣刀加工出来的工件表面质量较好,工件表面粗糙度均值为0.692μm。结论相同刀刃数量且结合力良好的涂层铣刀相比较,Ta-C涂层铣刀较普通类金刚石涂层铣刀加工出来的工件表面粗糙度平均值低,同种涂层加工得到的切屑表面微观形貌无明显差别。Ta-C涂层铣刀与普通类金刚石涂层铣刀切削铝合金时,抑制粘刀效果都十分明显,但Ta-C涂层铣刀效果更优。     

新式镗杆的调整机构

导言 自动化加工设备,如自动线和回转台式机床的效率在很大程度上与其负荷率有关。负荷率在机械方面又在很大的程度上受刀具寿命和磨损的影响。在这方面,对加工窄公差和高光洁度孔的扩孔工具就提出了一个特殊的课题。刀具使用可能性的界限并不是由于磨损而使刀刃丧失了适合于切削的正确的几何形状,从而使切削力升高到不允许的程度,而是由于磨损使刀刃与工件的相对位置发生变化,因而超出了对孔所要求的公差范围。因为这种情况只在相当短的切削时间之后就可达到,于是就研制了一些对镗杆自动调整的装置。这种装置根据对所加工的孔自     

机械加工刀具的成分设计与切削性能研究

对比分析了陶瓷刀具和聚晶立方氮化硼刀具在不同切削加工参数下的硬态切削表面性能,并分析了刀具表面的磨损形貌特征。结果表明,陶瓷刀具和立方氮化硼刀具的表面粗糙度都随着切削速度和后刀面磨损程度的增加而降低;随着进给量的增加,陶瓷刀具和立方氮化硼刀具的表面粗糙度逐渐上升;切削深度对刀具表面粗糙度的影响不大。CBN刀具的磨损机制主要为磨粒磨损和氧化磨损。     

基于二维超声振动辅助的钛合金切削加工分析与试验研究

针对普通切削时钛合金表面质量较差的问题,将二维超声辅助切削用于钛合金的加工过程。对钛合金的超声振动切削理论进行分析,找出影响刀具运动轨迹及切削力的因素;设计基于二维超声振动的钛合金表面切削试验,研究超声振动对切削力、工件表面形貌以及刀具寿命的影响。结果表明:与普通切削相比,二维超声振动辅助切削可以有效降低加工中的切削力,减轻加工过程对刀具的冲击,提高刀具的耐用度;且在相同加工条件下,二维超声振动加工时的切削力下降了47.7%,工件表面轮廓平均高度减小了40.9%,刀具的使用寿命提高了近1倍。      

切削刃数量对球墨铸铁铣削性能及表面形貌特征的影响

目的 提高球墨铸铁铣削表面质量和刀具寿命。方法 通过刀具轨迹计算和切削试验,研究球墨铸铁平面铣削过程中切削刃数量对切削性能、刀具磨损和表面形貌特征的影响,并用分形维数和表面粗糙度共同表征表面形貌。结果 刀具轨迹分析表明,由于铣削过程中,刀具切削方向和进给方向间的夹角不断变化,铣削表面不同位置和方向的表面形貌存在差异,进而导致表面粗糙度存在较明显的差异。通过铣削试验研究切削刃数量对铣削表面不同位置和方向的几何特征的影响规律发现,随着切削刃数量的成倍增加,切削力显著增加,同时刀具磨损量降低了36.5%,表面粗糙度值降低了39.2%,表面轮廓分形维数值增加了4.8%。结论 增加切削刃数量可以使每齿切削力和刀具磨损均显著减小,刀具寿命显著增加,同时表面粗糙度减小,分形维数增大,即切削刃数量的增加使表面质量更好,表面轮廓结构更复杂。     

金刚石涂层刀具加工石墨的切削性能

为充分对比不同类型金刚石涂层刀具的切削性能,定制几种不同类型金刚石涂层刀具进行等静压石墨切削加工,并与WC硬质合金刀具和TiAlN涂层刀具的切削情况对比,分析不同类型金刚石涂层刀具的涂层形貌、切削寿命、加工后的表面质量以及切削力。结果表明:制备的金刚石涂层刀具的涂层形貌主要为纳米晶和微晶,其寿命是硬质合金和TiAlN涂层刀具的10倍以上,且几种不同类型的金刚石涂层刀具寿命差异较小;金刚石涂层表面的晶粒细化可以降低加工表面的粗糙度和切削力,涂层脱落是金刚石刀具的主要磨损形式。      

Roughness and texture generation on end milled surfaces

Plane surface generation mechanism in flat end milling is studied in this research. The bottom of a flat end mill has an end cutting edge angle that plays an important role in surface texture. Surface texture is produced by superposition of conical surfaces generated by the end cutting edge rotation. The machined surface is cut once again by the trailing cutting edge. This back cutting phenomenon is frequently observed on surfaces after finishing. Tool run-out and tool setting error including tool tilting and eccentricity between tool center and spindle rotation center are considered together with tool deflection caused by cutting forces. Tool deflection affects magnitude of back cutting and the surface form accuracy. As a result, the finished surface possesses peaks and valleys with form waviness. Surface topography parameters such as RMS deviation, skewness and kurtosis are used for evaluating the generated surface texture characteristics. Through a set of cutting tests, it is confirmed that the presented model predicts the surface texture and roughness parameters precisely including back cutting effect.     

Influence of feed, eccentricity and helix angle on topography obtained in side milling processes

Influence of feed, eccentricity and helix angle on surface roughness is presented for side milling operations with cylindrical tools. A model was developed to predict surface topography as well as different roughness parameters. Roughness topography was obtained for one specific tool having grinding errors and eccentricity, for different helix angles.It was found that, as feed increases the number of cutting edge marks on the workpiece’s surface per revolution maintains or increases. As grinding errors and eccentricity increase, the number of cutting edge marks tends to decrease. Regarding helix angle, it was observed that roughness profile does not change along the workpiece’s height if no helix angle is considered. When helix angle is considered and the tool has both high eccentricity and high runout due to grinding errors, roughness heterogeneity bands are observed. The bands’ pattern is repeated along each helix pitch. The higher the helix angle, the narrower the roughness heterogeneity bands become.     

Analytical model to determine the critical feed per edge for ductile-brittle transition in milling process of brittle materials

Brittle materials like glass are considered difficult-to-machine because of their high tendency towards brittle fracture during machining. The technological challenge in machining such brittle materials is to achieve material removal by plastic deformation rather than characteristic brittle fracture. In ductile mode machining, the material is removed predominantly by plastic deformation and any cracks produced due to possible fracture in the cutting zone are prevented from extending into the machined surface. This is achieved by selecting an appropriate cutting tool and suitable machining parameters. In ductile machining by milling process, fracture induced cracks are diverted away from final machined surface by selecting a suitable feed per edge less than a critical threshold value. Hence determination of critical feed per edge is of paramount importance to achieve ductile mode machining by milling process. This paper presents an analytical model based on fracture mechanics principles to predict the critical feed per edge in milling process of glass. The size and orientation of cracks originating from brittle fracture during machining have been quantified by using indentation test results and the critical value of feed per edge has been determined analytically as a function of intrinsic materials properties governing brittle fracture and plastic deformation. Furthermore, an equivalent tool included angle has been suggested for machining operation as against the indenter included angle to correlate the indentation and machining test results with improved degree of accuracy. Experimental results validated the proposed model fairly accurately. It has been established that if the longest cracks oriented in radial direction to the cutting edge trajectory are prevented from reaching the final machined surface by selecting a feed per edge less than or equal to a critical value, a crack-free machined surface can be achieved.     

Presentation of a novel cutting technology for precision machining of hardened, rotationally symmetric parts

In this paper a new cutting technology similar to hard turning is presented to cut rotationally symmetric parts made of hardened materials. This novel technology, which is named rotational turning, is based on a combination of hard turning and circular milling. An analytical model is developed to describe the engagement parameters between tool and workpiece. It is shown by the model, that the virtual tool corner radius in rotational turning, which takes effect during the cutting process, is more than 50 times larger than in state of the art hard turning. Due to this, feed marks, which are common in turning, can be reduced to a level, where they are not measurable anymore. It can be shown in experiments, that the minimum achievable surface roughness is therefore not limited by the feed rate anymore, like in turning processes usual, but by other effects like the waviness of the cutting edge.     

A study of the surface scallop generating mechanism in the ball-end milling process

This paper presents the model, simulation and experimental verification of the scallop formation on the machined surface in the ball-end milling process. In the milling process, the cutting edges of the cutter are in a motion of combined translation and rotation. The periodical variation of the cutting edge orientation during spindle rotation results in two kinds of scallops generated on the machined surface: the pick-interval scallop and the feed-interval scallop. Because of the low feed and comparably large pick used in the conventional ball-end milling process, the emphasis of previous works has been placed on studying the geometric generating mechanism of the pick-interval scallop while the feed-interval scallop has been largely ignored. Trend of the high-speed and high efficiency machining, however, has pushed the feed reaching the same level of the pick. For the high-speed machining where the high feed/pick ratio is used, the feed-interval scallop must be taken into account. This paper presents a new model that describes the path-interval and feed-interval scallops generating mechanism in the ball-end milling processes. Parameters such as the tool radius, feed/pick ratio, initial cutting edge entrance angle, and tool-axis inclination angles have been studied and experimental verified. It was found that the feed-interval scallop height was 3–4 times large than the path-interval scallop height at the high-speed machining case. The scallop height was continuously reduced by increasing the tool-axis inclination angle. An inclination angle up to 10° is, however, good enough for most tool diameters from the surface roughness viewpoint.     

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。     

Experimental investigation on cutting mechanism of laser sintered material using small ball end mill

This paper describes an experimental investigation on the cutting mechanism of laser sintered material using small ball end mill focusing on the temperature of the cutting edge. Sintered material was produced by irradiating a laser beam on a layer of loose fine SCM–Ni–Cu powder. Bulk carbon steel AISI 1055 was selected as reference steel. The influence of cutting conditions, tools diameter and unsintered metallic powder on the cutting edge temperature were examined. Comparison of the cutting edge temperature between the peripheral and surface milling were investigated. Investigations of the tool life and wear mechanisms in cutting the sintered material and AISI 1055 were also carried out. Results indicated that the cutting edge temperature for sintered material was higher than for bulk AISI 1055. Cutting at the outer surface of sintered material produced higher temperature than at the inner surface. The temperature of the cutting edge was greatly influenced by the cutting speed followed by depth of cut and feed per tooth. Cutting temperature for different tool's diameter was almost similar under the same rotational speeds and cutting conditions. Cutting tool temperature in peripheral milling was higher than in surface milling. Adhesion of the work material and chipping were the main wear mechanisms of the ball end mill in cutting sintered material.     

Cutting process of glass with inclined ball end mill

Cutting processes with ball end mills are discussed for machining microgrooves on glasses. A surface is finished in undeformed chip thickness less than 1 μm at the beginning and at the end of the cut during the cutter rotation. The milling process is applied to glass machining. A crack-free surface can be finished in a large axial depth of cut more than 10 μm. Because glass undergoes almost no elastic deformation, roughness on a cutting edge in glass machining has a larger influence on surface finish than that of metal machining. The rotational axis of the tool is inclined to improve the surface finish. The cutting processes are modeled to show the effect of the tool inclination on the machined surface with considering the edge roughness. The tool inclination compensates for deterioration of the surface finish induced by the edge roughness in the presented model. The improvement of the surface finish is verified in the cutting experiments with the tool inclination. The orthogonal grooves 15–20 μm deep and 150–175 μm wide, then, are machined with the crack-free surfaces to prove efficiency and surface quality in the milling process.     

Experimental study of surface roughness in slot end milling AL2014-T6

The aim of this work was to analyze the influence of cutting condition and tool geometry on surface roughness when slot end milling AL2014-T6. The parameters considered were the cutting speed, feed, depth of cut, concavity and axial relief angles of the end cutting edge of the end mill. Surface roughness models for both dry cutting and coolant conditions were built using the response surface methodology (RSM) and the experimental results. The results showed that the dry-cut roughness was reduced by applying cutting fluid. The significant factors affecting the dry-cut model were the cutting speed, feed, concavity and axial relief angles; while for the coolant model, they were the feed and concavity angle. Surface roughness generally increases with the increase of feed, concavity and axial relief angles, while concavity angle is more than 2.5°.