共查询到19条相似文献,搜索用时 62 毫秒
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硬态干式车削淬硬钢SKD11表面粗糙度试验研究 总被引:3,自引:0,他引:3
应用单因素法研究了PCBN 刀具硬态干式切削淬硬钢SKD11过程中,进给量、切削速度、背吃刀量、刀尖圆弧半径和倒棱宽度等参数对表面粗糙度的影响规律. 相似文献
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通过使用PCBN刀具精密干式车削不同淬硬状态(51、55、58、62、65±1 HRC)工具钢Cr12MoV的试验,分析了淬硬状态对三向切削力的影响规律。试验表明:随工件硬度的升高,主切削力与径向力先逐渐增大,后急剧减小;而进给力在很小范围内波动。EDS分析进一步表明:工件硬度达到65±1 HRC时,会因工件表面材料的脆性而减小切削力;而当工件硬度达到62±1 HRC时,由于切削温度的升高而在切屑与刀具前面产生粘结作用,从而引起切削力增大。试验结果对精密干式切削淬硬工具钢具有实际的指导意义与参考价值。 相似文献
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采用陶瓷刀具进行淬硬轴承钢GCr15的硬车削加工试验,并通过正交试验分析和方差分析给出试验范围内的最优加工参数组合。基于所建立的表面粗糙度经验模型,分析切削速度、进给量和刀尖圆弧半径对表面粗糙度的影响规律。试验与仿真分析表明,增大刀尖圆弧半径可有效降低已加工表面的表面粗糙度,而提高切削速度可使表面粗糙度略有下降;当进给量增大时,表面粗糙度几乎线性增加。同时,进给量对表面粗糙度的影响最大,刀尖圆弧半径次之,而切削速度的影响微弱。 相似文献
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本文对我公司生产的变速箱副箱减速齿轮热后车锥面的表面粗糙度影响因素进行分析,对零件表面粗糙度及加工零件数量统计,确定最优加工参数组合,提高刀具耐用度,保证零件表面质量。 相似文献
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涂层硬质合金刀具干式切削淬硬钢的试验研究 总被引:1,自引:0,他引:1
通过采用涂层硬质合金刀具对淬硬45钢硬态干式切削试验,分析硬态干式切削淬硬钢的特点,研究了涂层硬质合金刀具及其几何参数的优化,讨论了涂层硬质合金刀具磨损形式、鼠具耐用度及加工表面粗糙度,得出院要中应用于实际干式切削加工的切削条件和参数。 相似文献
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T. I. El Wardany Professor M. A. Elbestawi 《The International Journal of Advanced Manufacturing Technology》1997,13(1):1-16
This paper presents a stochastic model for predicting the tool failure rate in turning hardened steel with ceramic tools. This model is based on the assumption that gradual wear, chemical wear, and premature failure (i.e. chipping and breakage) are the main causes of ending the tool life. A statistical distribution is assumed for each cause of tool failure. General equations for representing tool-life distribution, reliability function, and failure rate are then derived. The assumed distributions are then verified experimentally. From the experimental results, the coefficients of these equations are determined. Further, the rate of failure is used as a characteristic signature for qualitative performance evaluation. The results obtained show that the predicted rate of ceramic tool failure is 20% (in the first few seconds of machining) and it increases with an increase in cutting speeds. These results indicate that there will always be a risk that the tool will fail at a very early stage of cutting. Such a possibility should not be overlooked when developing proper tool replacement strategies. Finally, the results also give the tool manufacturers information which can be used to modify the quality control procedures in order to broaden the use of ceramic tools.Nomenclature
c
constant
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ch
chamfer width of the tool, mm
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d
depth of cut, mm
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h
i
hardness value at theith location on the workpiece during machining
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h
mean ofh
1,h
2,h
3, ...,h
nn
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n
hardness mean location
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m
Meyer exponent determined experimentally to define the nonlinear relation between the cutting force and the ratioh
i/h
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f
feedrate, mm rev–1
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f(t)
probability density function of tool failure
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f
1(t)
probability density function of tool failure due to breakage caused by tool quality
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f
2(t)
probability density function of tool failure due to breakage caused by workpiece condition
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f
3(t)
probability density function of tool failure due to tool chipping caused by chemical wear
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f
4(t)
probability density function of tool failure due to flank wear
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f
5(t)
probability density function of tool failure due to crater wear
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O()
error
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t
cutting time, min
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x
1,x
2,...,x
n
independent variables
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A
i
instantaneous area of contact between the tool and the workpiece
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C
1
chip load, which can be determined as a function of the cutting conditions and tool geometry
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K
I
crater wear index
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K
T
maximum depth of crater wear on tool face, mm
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K
M
crater centre distance, mm
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N
number of failures
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P(t)
probability function of tool failure
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P
j(t)
corresponding probability of failure, such that 1j5
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R
tool nose radius, mm
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R(t)
reliability function
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R
j(t)
corresponding reliability function, such that 1j5
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T
V
estimate of tool life for a set value of average flank wear (V
B
*
)
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T
K
estimate of tool life for a set value of maximum depth of crater wear (K
T
*
)
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V
cutting speed, m/min
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V
B
average tool wear, mm
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Z(t)
instantaneous failure rate or hazard function
- 3
shape parameter in the Weibull probability density function
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rake angle
- 3
scale parameter in the Weibull probability density function, min
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failure rate of the cutting tool
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mean of a logarithmic normal distribution function
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standard deviation of a logarithmic normal distribution function
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tool wear function
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time corresponding to the occurrence of tool failure
- (.)
standard logarithmic normal distribution function 相似文献
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T. Tamizharasan T. Selvaraj A. Noorul Haq 《The International Journal of Advanced Manufacturing Technology》2006,28(7-8):671-679
Hard turning is a profitable alternative to finish grinding. The ultimate aim of hard turning is to remove work piece material
in a single cut rather than a lengthy grinding operation in order to reduce processing time, production cost, surface roughness,
and setup time, and to remain competitive. In recent years, interrupted hard turning, which is the process of turning hardened
parts with areas of interrupted surfaces, has also been encouraged. The process of hard turning offers many potential benefits
compared to the conventional grinding operation. Additionally, tool wear, tool life, quality of surface turned, and amount
of material removed are also predicted. In this analysis, 18 different machining conditions, with three different grades of
polycrystalline cubic boron nitride (PCBN), cutting tool are considered. This paper describes the various characteristics
in terms of component quality, tool life, tool wear, effects of individual parameters on tool life and material removal, and
economics of operation. The newer solution, a hard turning operation, is performed on a lathe. In this study, the PCBN tool
inserts are used with a WIDAX PT GNR 2525 M16 tool holder. The hardened material selected for hard turning is commercially
available engine crank pin material. 相似文献
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Influence of tool wear on surface roughness in hard turning using differently shaped ceramic tools 总被引:3,自引:0,他引:3
Hard turning has been applied in many cases in producing bearings, gears, cams, shafts, axels, and other mechanical components since the early 1980s. Mixed ceramics (aluminum oxide plus TiC or TiCN) is one of the two cutting tool materials (apart from PCBN) widely used for finish machining of hardened steel (HRC 50–65) parts, especially under dry machining conditions and moderate cutting speed ranging from 90 to 120 m/min. This paper reports an extensive characterization of the surface roughness generated during hard turning (HT) operations performed with conventional and wiper ceramic tools at variable feed rate and its changes originated from tool wear. Moreover, it compares some predominant tool wear patterns produced on the two types of ceramic inserts and their influence on the alteration of surface profiles. After the hard turning tests, the relevant changes of surface profiles and surface roughness parameters were successively registered and measured by a stylus profilometer. In this investigation, a set of 2D surface roughness parameters, as well as profile and surface characteristics, such as the amplitude distribution functions, bearing area curves and symmetrical curves of geometrical contact obtained for the machined surface, were determined and analyzed. A novel aspect of this research is that the notch wear progress at the secondary cutting (trailing) edges was found to produce the substantial modifications of the individual irregularities, and constitute the altered surface profiles. Moreover, this research contributes to practical aspects of HT technology due to exploring the relations between the tool state at different times within the tool life and the relevant surface roughness characterization. 相似文献
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Study on the surface roughness of specimen is a significant field of research because this parameter affects the performance of the machined parts. Meanwhile, the evaluation of surface roughness of specimens using a vision system via the images captured from the specimen is an interesting method which is widely used. Although the effect of flank and crater wear has been investigated extensively in the past researches on surface profiles, some reports indicated that, in finish turning, the nose radius wear has a greater effect on the surface profile of specimen. Although, vibration can affect the surface profile of a specimen in rough turning, the final surface profile in the product used is usually shaped by finish turning that may not be affected by vibration using the robust machine tool. In this work, a machine vision was used to capture the images of the tool tip in-cycle. The 2-D images of the nose area of tool tips were used to simulate the surface profile of specimens in finish turning. The simulated images of specimens in a range of machining condition were detected using the algorithm of this work. The results showed that this method can be used successfully to simulate and evaluate the surface profile of a specimen in finish lathe machining as a fingerprint of the tool tip. This method can be used for forecasting the final surface profile in order to control the performance of products. 相似文献
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The surface texture of a milled surface is an inherently important process response in finish milling. It is one of the most commonly used criteria to determine the machinability of a particular workpiece material. However, literature survey on the study of the surface topography analysis relating to the cutter path orientations when high speed finish inclined milling is scant. Previous works were either involved in conventional milling of easy-to-cut workpiece materials or machining at different workpiece inclination angles. Furthermore, none of the previous work has detailed the true surface topography of the machined surface with regards to the cutter condition. Instead, the works provided quantitative values in terms of the Ra value. This article is concerned with evaluating cutter path orientations on an inclined workpiece angle of 75° to simulate finish milling of free form moulds and dies. Surface topography effects are assessed with regards to different cutter path orientations on its surface. The aims of this study are to provide an in-depth understanding on the surface texture produced by various cutter path orientations when high speed finish inclined milling hardened steel at a workpiece inclination angle of 75° using surface topography analysis and determine the best cutter path orientation with respect to the best surface texture achieved. 3D topography maps together with 2D surface profiles are used to assess the experimental results. The conclusion is that milling in a single direction vertical upward orientation gave the best workpiece surface texture. 相似文献
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In present work performance of coated carbide tool was investigated considering the effect of work material hardness and cutting parameters during turning of hardened AISI 4340 steel at different levels of hardness. The correlations between the cutting parameters and performance measures like cutting forces, surface roughness and tool life, were established by multiple linear regression models. The correlation coefficients found close to 0.9, showed that the developed models are reliable and could be used effectively for predicting the responses within the domain of the cutting parameters. Highly significant parameters were determined by performing an Analysis of Variance (ANOVA). Experimental observations show that higher cutting forces are required for machining harder work material. These cutting forces get affected mostly by depth of cut followed by feed. Cutting speed, feed and depth of cut having an interaction effect on surface roughness. Cutting speed followed by depth of cut become the most influencing factors on tool life; especially in case of harder workpiece. Optimum cutting conditions are determined using response surface methodology (RSM) and the desirability function approach. It was found that, the use of lower feed value, lower depth of cut and by limiting the cutting speed to 235 and 144 m/min; while turning 35 and 45 HRC work material, respectively, ensures minimum cutting forces, surface roughness and better tool life. 相似文献
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通过改变高速车削淬火钢(Cr12)的切削用量,对切削力、切削温度、加工表面质量等进行了研究,结果表明合理选择切削用量,高速硬车削淬火钢可显著提高生产率及加工表面质量,并在一定程度上可取代磨削加工。 相似文献
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通过改变高速车削淬火钢(Cr12)的切削用量,对切削力、切削温度、加工表面质量等进行了研究,结果表明合理选择切削用量,高速硬车削淬火钢可显著提高生产率及加工表面质量,并在一定程度上可取代廖削加工。 相似文献
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Mohamed Elbah Mohamed Athmane Yallese Hamdi Aouici Tarek Mabrouki Jean-François Rigal 《Measurement》2013
This study considers the comparison between the surface roughness criteria (Ra, Rz and Rt) of the wiper inserts with conventional inserts during hard turning of AISI 4140 hardened steel (60 HRC).The planning of experiments was based on Taguchi’s L27 orthogonal array. The response surface methodology (RSM) and analysis of variance (ANOVA) were used to check the validity of quadratic regression model and to determine the significant parameter affecting the surface roughness. The statistical analysis reveals that the feed rate and depth of cut have significant effects in reducing the surface roughness. The optimum machining conditions to produce the best possible surface roughness in the range of this experiment under these experimental conditions searched using desirability function approach for multiple response factors optimization. The results indicate that the surface quality obtained with the wiper ceramic insert significantly improved when compared with conventional ceramic insert is 2.5. Roughness measurements reveal a dependence on CC6050WH tool wear. However, although the wear rises up to the allowable flank wear of value 0.3 mm, roughness Ra did not exceeded 0.9 μm. 相似文献