共查询到20条相似文献,搜索用时 31 毫秒
1.
The removal of macro-burrs formed after drilling has always been a difficult engineering problem, especially on inclined exit surfaces with intersecting holes. A new deburring tool is developed to remove burrs on inclined exit surfaces. The performance of the proposed deburring tool is analyzed according to changes in parameters including tool geometry, the deburring direction, and cutting conditions. Based on our analysis, proper tool geometry is suggested, and an efficient deburring method and deburring conditions are determined which satisfy the chamfered geometry and surface roughness of holes. 相似文献
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Elimination, or reduction, of burrs formed during machining is drawing focus of manufacturers and researchers since long or suppressing a burr regarding its formation or removal of it through a suitable deburring process. Deburring is an extra process often required to undertake, and it involves additional time and cost. Presence of burr may cause several problems, such as difficulty in assembly, dimensional inaccuracy, injury to the operator, etc. Like other industries, avoidance of burr on milled component surfaces in railways is of concern. In the present investigation, formation of burr in face milling is tried to reduce by beveling the exit edge of blocks of medium carbon steel (45C8) which is widely used in railways for manufacture of different components. Cutting conditions are also varied to observe the effect on burr formation. It is observed that at an exit edge bevel angle of 15°, negligible burr is formed at most of the cutting conditions undertaken, and hence, recommended. 相似文献
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Young Hun Jeong Byung HanYoo Han Ul Lee Byung-Kwon Min Dong-Woo Cho Sang Jo Lee 《Journal of Materials Processing Technology》2009,209(14):5399-5406
Demands for miniature components are rapidly increased in the field of optics, electronics, and medicine. Various machining methods have been introduced for the fabrication of complex three-dimensional microfeatures. However, burrs, which are an undesired but unavoidable by-product of most machining processes, cause many problems in assembly, inspection, process automation, and precision component operation. Moreover, as feature sizes decrease, burr problems become more difficult to resolve. To address this problem, several deburring methods for microfeatures have been introduced, including ultrasonic, magnetic abrasive, and electrochemical machining methods. However, these methods all have some shortcomings, such as mechanical damage, over-machining, changes in the material properties of the finished surface, sharp edge blunting, and the requirement for subsequent processing to remove chemical residues. In this study, microelectrical discharge machining (micro-EDM) using low discharge energy and a small-diameter cylindrical tool is introduced for deburring microfeatures. This method allows the machining of very small amounts of conductive materials regardless of the material hardness, and provides easy access to small microscale features for selective deburring. The burr geometry generated by the micromilling process was investigated to establish a deburring strategy using micro-EDM. The proposed method was verified by experimental results using aluminum, copper, and stainless steel workpieces. 相似文献
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为消除由纯钼和纯钛加工成的待加工件表面出现的金属重熔层和毛刺,选用电化学去毛刺工艺来去除这些待加工件上的金属重熔层和毛刺。电化学去毛刺工艺利用电化学阳极溶解的原理去除间隙的毛刺,其具有对工件无机械力、与工件材料硬度无关等优点因此其在加工高硬度和高韧性的金属工件上有着天然优势。通过使用不同电解液,运用电化学去毛刺的加工手段分别测试用电火花线切割加工过的钼片和钛片的去毛刺效果,得到了在30℃的电解液温度和5V的加工电压以及5s的加工时长下,电化学去毛刺加工在对纯钼和纯钛的加工上有着很明显的效果的结果。 相似文献
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A various number of products exist which require a clean-sheared edge due to function or surface feel. Traditionally, these
parts are produced on fine blanking presses with three separate and distinct movements. Shaving, in particular counter-shaving
is a shearing operation to improve the edge quality of a blanked part or punched hole. This paper introduces a progressive
die tool to realize the counter-shaving process on a single acting press. Advancing the chip flow through choosing a cutter
angle can achieve up to a 85% clean-sheared edge and rectangular edge. Thereby, a sharp-edged transition—without any rollover
depth—between the upper surface of the sheet metal and the sheared-edge are formed. The end of the clean-sheared edge is followed
by a tear which shapes a burr in the form of a triangular lappet, which can be deburred in a subsequent vibratory grinding
process. Experimental results of different process parameters for two sheet metal materials at three thicknesses are discussed
and compared to finite element calculations.
The presented research work was supported by the German Research Foundation (DFG). 相似文献
8.
Experimental observation and analysis of burr formation mechanisms in face milling of aluminum alloys 总被引:3,自引:0,他引:3
The purpose of this paper is to study the burr formation mechanisms in face milling process, and to investigate the influence of cutting conditions on burr formation in face milling of aluminum alloys. The fly milling cutter is used to carry out single-tooth face milling tests. Three aluminum alloys were tested: Al 1100 (cold drawn), Al 2024-T4 and Al 6061-T6. It is found that the burr geometry is strongly dependent upon the in-plane exit angle. Five types of burrs were observed in the experiments: knife-type, wave-type burr, curl-type, edge breakout and secondary burr. Formation mechanisms of each type of these burrs are discussed in details. The relationship between their existence and the machining condition is indicated. The machining guideline in face milling is given at the end of the paper to reduce burr size effectively through the formation of secondary burr. 相似文献
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Previous research on burr formation in face milling operations has usually been limited to the study of the rollover burr in the cutting direction and/or to a few machining parameters. This paper presents the results of an experimental study on the influence of the main cutting parameters on the formation of the more important burrs produced in face milling operations, namely exit burr in the cutting direction, exit burr in the feed direction and the burr formed at the top edge in a square shoulder face milling operation. Feed per tooth (Sz), cutting velocity (V), axial depth of cut (a) and exit angle (EXA) were the cutting parameters investigated. The effects of mode of milling, tool nose geometry and tool coating were also investigated to a lesser extent. The results show that exit angle and depth of cut are the cutting parameters which have a major influence on the exit burr in the cutting direction, whereas the exit burr in the feed direction is mainly affected by depth of cut. The top burr is very small and only slightly influenced by cutting conditions. It is also shown that down-milling can effectively eliminate the formation of burrs in some cases, whereas an unfavourable tool nose geometry can double the size of buns. 相似文献
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Regarding intersecting holes, the edges of cut are often difficult to access, as they are located inside the components. Hence
it requires a lot of time and money to deburr them. In addition, burrs which come off in the later operation can lead to resultant
damages. Examinations of intersecting holes showed that the effective exit surface angle, the angle between drill wall and
exit surface, is crucial for burr formation. Based on the burr calculation for exit surfaces perpendicular to the drill axis,
a method of calculation was developed out of the experimental results. By means of this calculation method the burr value
g can be predicted for the short hole drilling of intersecting holes. 相似文献
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Increasing demands on function and performance call for burr-free workpiece edges after machining. Since deburring is a costly and non-value-added operation, the understanding and control of burr formation is a research topic with high relevance to industrial applications. Following a review of burr classifications along with the corresponding measurement technologies, burr formation mechanisms in machining are described. Deburring and burr control are two possible ways to deal with burrs. For both, an insight into current research results are presented. Finally, a number of case studies on burr formation, control and deburring along with their economic implications are presented. 相似文献
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G. M. Kim P. J. Cho C. N. Chu 《International Journal of Machine Tools and Manufacture》2000,40(2):277-291
The cutting force in ball-end milling of sculptured surfaces is calculated. In sculptured surface machining, a simple method to determine the cutter contact area is necessary since cutting geometry is complicated and cutter contact area changes continuously. In this study, the cutter contact area is determined from the Z-map of the surface geometry and current cutter location. To determine cutting edge element engagement, the cutting edge elements are projected onto the cutter plane normal to the Z-axis and compared with the cutter contact area obtained from the Z-map. Cutting forces acting on the engaged cutting edge elements are calculated using an empirical method. Empirical cutting mechanism parameters are set as functions of cutting edge element position angle in order to consider the cutting action variation along the cutting edge. The relationship between undeformed chip geometry and the cutter feed inclination angle is also analyzed. The resultant cutting force is calculated by numerical integration of cutting forces acting on the engaged cutting edge elements. A series of experiments were performed to verify the proposed cutting force estimation model. It is shown that the proposed method predicts cutting force effectively for any geometry including sculptured surfaces with cusp marks and a hole. 相似文献
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A new predictive force model for a single-tooth face milling cutter with a chamfered main cutting edge has been derived. Machining tests has been conducted for fly cutting with a chamfered main cutting edge tools on plane surfaces. An S45C medium carbon plate has been used as the workpiece matrial. Force data from these tests were used to estimate the empirical constants of the mechanical model and to verify its prediction capabilities. The results show a good agreement between the predicted and measured forces.Since tool manufacturers does not provide tools with selected combinations of chamfered main cutting edge, radial angle, axial angle and inclination angles, tool holders manufactured in-house were used in the tests. The tips were prepared to the required geometry using a tool grinder. 相似文献
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Burr minimizing scheme in drilling 总被引:3,自引:0,他引:3
Sung-Lim Ko Jae-Eun Chang Gyun-Eui Yang 《Journal of Materials Processing Technology》2003,140(1-3):237-242
In conventional drilling, burr formation can be changed by varying the drill’s geometry, i.e. the step angle and point angle. To minimize burr formation, it is proposed that a step drill be used. The step drill performs front edge cutting before step edge cutting. The burr formed in first cutting by front cutting edge can be removed in second cutting by step edge. In particular, new burrs are formed through the second cutting. They can be minimized by changing the drill’s geometry. A laser sensor is used to measure the burr formed in the drilling. 相似文献
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通过建立单颗磨粒微切削模型,分析了铰珩毛刺的形成过程。以侧边毛刺截面积为毛刺评价指标,研究了切削深度、切削宽度和刃倾角对毛刺形成的影响规律,并通过试验验证模型的准确性。分析结果显示:工件材料的塑性变形是影响毛刺形成的主要因素,塑性变形量越大,毛刺截面积越大;切削深度、切削宽度增加,毛刺截面积明显增大;刃倾角由负值向正值变化时,由于材料塑性变形量和流动方向的变化,毛刺尺寸逐渐增大。 相似文献
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行星复合铣削方法是复合加工方法的一种实现形式,该加工方法所产生的切削力较普通端铣加工的切削力有大幅度的降低,从而能有效地降低切削热、减少工件变形、提高刀具寿命。行星复合铣削方法切削力大幅度地降低的主要原因是该方法的切削轨迹使其能将厚切削层分解为细小的切削层,而该方法中的立铣刀的螺旋角和半径对实际切削力的影响很小。行星复合铣削方法在刀盘低速旋转时就能实现高速切削,有效地避开了高速旋转刀盘的动平衡问题,结合其切削力小的优势,通过增大刀盘直径并增加立铣刀数量来提高加工效率。行星铣刀采用行星轮系结构,能够达到行星复合铣削方法切削轨迹要求,具有扭矩大、运转可靠等优势。 相似文献
18.
Liangshan Xiong Ning Fang Hanming Shi 《International Journal of Machine Tools and Manufacture》2009,49(7-8):667-677
The present study aims at the development of a new methodology for designing a curve-edged twist drill with an arbitrarily given distribution of the cutting angles along the tool cutting edge. The new methodology consists of 81 major mathematical equations and is developed using a method of mapping relevant planes and straight lines of a cutting tool (such as the cutting plane and the cutting edge) as corresponding image points and image lines on a projection plane. The developed methodology is used to intuitively and graphically analyze and determine the relationship between the orientation of the cutting edge and the cutting angles at each point on the cutting edge. A set of image points and image lines is established to calculate the cutting angles on the cutting edge of a twist drill, including the working tool rake angle, the working tool inclination angle, the working cutting edge angle, and the working normal rake angle. Three computer case studies are provided to show curved cutting edges that correspond, respectively, to a linear distribution of the working tool rake angle, a combined linear and uniform distribution of the working tool rake angle, and a linear distribution of the working tool inclination angle along the tool cutting edge. Finally, a set of metal drilling experiments is performed to compare the drilling torque and the thrust force between a conventional straight-edged twist drill and a new curve-edged twist drill that has a combined linear and uniform distribution of the working tool rake angle along the tool cutting edge. The experimental results show that the new curve-edged drill reduces the drilling torque by 28.5% and the thrust force by 24.6% on average. 相似文献
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The compliance with the quality requirements of components is essential for the functionality of the whole product. With respect to parts with face-milled faces, the surface quality and the shape of the workpiece edges are of great interest. Frequently, these faces take over the function of seal faces where high demands on the surface integrity and burr formation exist. To ensure the workpiece quality that is required, nowadays additional processes for deburring are often necessary. To avoid deburring, the modification of machining processes is a promising approach. In this study, the influence of process cooling on workpiece quality is investigated. Using this approach, two effects are expected. The cooling is used to minimize a reduction of flow stress generated from the process heat, which than leads to a lower formability. The second effect relates to the kinetic energy of the snow blast for deburring by deformation and breakage of the burrs. Using a process cooling with carbon dioxide, the surface quality is enhanced and the burr formation is minimized. 相似文献