共查询到20条相似文献,搜索用时 78 毫秒
1.
系统概括了国内外时金属切削毛刺的预报预测研究现状,分析了有限元法在毛刺形成过程、形态度尺寸大小和界限转换条件的定量或定性预测预报中的具体应用,为系统深入地研究切削毛刺提供了理论基础. 相似文献
2.
3.
4.
5.
毛刺是金属切削加工中产生的常见现象之一,它的尺寸和形状直接影响到工件的尺寸精度和形位精度,甚至影响到工件的使用性能及其寿命.随着机械制造业朝着高精度,高效率和自动化方向发展,对切削加工精度的要求越来越高.由于专家系统具有数据结构化,数据和应用程序的高度独立性、数据共享,并将数据冗余减少到最小限度等优点,在金属切削毛刺形成研究与控制上逐步得到了越来越广泛的应用,对加工精度起到了很好的效果.在分析现有毛刺研究成果的基础上,与专家系统进行了对比与分析,体现出了专家系统在毛刺研究领域应用具有的优点,并阐述了现有的金属切削毛刺专家系统的研究现状,指出了尚存在的一些问题,从而为今后毛刺专家系统的发展提供借鉴. 相似文献
6.
金属切削毛刺分类体系的研究及其应用 总被引:2,自引:0,他引:2
将金属切削毛刺生成同切削运动联系起来,提出并建立起切削运动-刀具切削刃毛刺分类体系,清晰地给出影响毛刺生成及变化的主要因素。将该分类体系应用于车削、钻削和磨削加工,表明切削运动-刀具切削刃毛刺分类体系定义明确、完整。简便易行。 相似文献
7.
8.
金属零件在切削加工过程中常会产生毛刺,毛刺的存在将严重地影响零件或产品的质量。影响毛刺生成的因素很多,如何防止和减少金属切削毛刺,应根据具体情况,采取相应措施。现就这一问题作一简要探讨性综述。一、从零件设计上避免生成毛刺1.选择合适的工件材料工件材料的物理机械性能对毛利的生成有很大影响,如变形硬化指数,延伸率,硬度和抗拉强度等。因此,在零件设计时,在满足强度要求的条件下,应尽可能的选用变形硬化指数和延伸率较小的材料,以减少金属切削加工时毛刺的生成。2采用合理的零件结构形状在金属切削加工中,毛刺主要… 相似文献
9.
10.
金属切削刀具磨损的监控和预报研究 总被引:3,自引:0,他引:3
介绍一种采用光电法直接测量刀具磨损值,用GMDH方法进行磨损规律的数学建模和寿命预报的方法,实验证明,该系统92%的预防误差小于7.2%,使刀具使用寿命提高43%以上。 相似文献
11.
Dr S. P. F. C. Jaspers J. H. Dautzenberg D. A. Taminiau 《The International Journal of Advanced Manufacturing Technology》1998,14(1):7-12
Orthogonal cutting experiments were carried out on steel at different feedrates and cutting speeds. During these experiments the chip temperatures were measured using an infrared camera. The applied technique allows us to determine the chip temperature distribution at the free side of the chip. From this distribution the shear plane temperature at the top of the chip as well as the uniform chip temperature can be found. A finite-difference model was developed to compute the interfacial temperature between chip and tool, using the temperature distribution measured at the top of the chip.Nomenclature
contact length with sticking friction behaviour [m]
-
c
specific heat [J kg–1 K–1]
-
contact length with sliding friction behaviour [m]
-
F
P
feed force [N]
-
F
V
main cutting force [N]
-
h
undeformed chip thickness [m]
-
h
c
deformed chip thickness [m]
-
i,j
denote nodal position
-
k
thermal conductivity [W m–2 K–1]
-
L
chip-tool contact length [m]
-
p
defines time—space grid, Eq. (11) [s m–2]
-
Q
C
heat rate entering chip per unit width due to friction at the rake face [W m–1]
-
Q
T
total heat rate due to friction at the rake face [W m–1]
-
Q
%
percentage of the friction energy that enters the chip
-
q
0
peak value ofq(x) [W m–2]
-
q
e
heat rate by radiation [W]
-
q(x)
heat flux entering chip [W m–2]
-
t
time [s]
-
T
temperature [K]
-
T
C
uniform chip temperature [°C]
-
T
max
maximum chip—tool temperature [°C]
-
T
mean
mean chip—tool temperature [°C]
-
T
S
measured shear plane temperature [°C]
-
x,y
Cartesian coordinates [m]
-
V
cutting speed [m s–1]
-
V
C
chip speed [m/s]
-
rake angle
- ,,
control volume lumped thermal diffusivity [m2 s–1]
-
emmittance for radiation
-
exponent, Eq. (3)
-
density [kg m–3]
-
Stefan-Boltzmann constant [W m–2 K4]
- (x)
shear stress distribution [N m–2]
-
shear angle 相似文献
12.
The use of volume of solid (VOS) approach in simulating metal cutting with chamfered and blunt tools
K.S. Al-Athel 《International Journal of Mechanical Sciences》2011,53(1):23-30
A new volume of solid (VOS) method is proposed for simulating metal cutting applications. The method utilizes the Eulerian finite element formulation along with a numerical scheme to calculate volume of solid fractions in empty elements or cells. The method is shown to overcome problems with existing finite element formulations and may easily track and model the unconstrained flow of the material at free boundaries. As a sample application, the method is used to study the effect of introducing a chamfer angle to the tool or using a blunt (worn) tool on some of the process variable and on the cutting forces both in the cutting and thrust directions. The results of the VOS method are compared to similar results obtained using the arbitrary Lagrangian-Eulerian approach and to experimental results that were performed for one sharp and two chamfered tools. 相似文献
13.
H. Trabelsi E. Kannatey-Asibu Jr. 《The International Journal of Advanced Manufacturing Technology》1991,6(3):220-231
Pattern-recognition analysis of sound radiation was developed as a basis for monitoring the metal-cutting process. The sound-pressure
signals radiated during cutting under fixed conditions were recorded using a sharp tool, a worn tool and a broken tool. A
round bar of heat-treated AISI 4340 steel was machined in cylindrical turning, using a titanium-carbide-coated cutting tool.
The spectral components in the 0–10 kHz range were used as features. Using resubstitution, signals coming from sharp and worn
tools were easily distinguished, resulting in a 100% classification with just two features, being the average of the low (0–5
kHz) and high (5–10 kHz) frequency ranges. With tool breakage, two acceptable classifications were obtained using independent
testing, the first with a performance of 100%, 75% and 100% for sharp, worn and breakage signals respectively, using nine
features, and the second with 80%, 88% and 80%, using eight features. 相似文献
14.
15.
16.
通过对Ti-6Al-4V钛合金和7075-T6铝合金组成的叠层材料进行干式钻削实验,分析了叠层次序、压紧力、进给量和转速对层间毛刺高度和宽度的影响,并观察了毛刺的微观形态。在实验中,当转速为2 000r/min,进给量为0.075mm/r,压力为0.3MPa,叠层顺序为Ti-6Al-4V在7075-T6上时,有最小的层间毛刺和层间毛刺形态。 相似文献
17.
基于热力耦合模型的金属切削过程有限元分析 总被引:2,自引:0,他引:2
基于有限元理论和热力耦合模型的研究,通过讨论切削过程中的关键技术,主要包括切削加工有限元方程的建立:构件材料的Johnson-Cook本构模型;切屑分离准则;材料断裂准则;接触摩擦模型;切削热的产生和分布;残余应力的分析和切削力的比较分析等,建立了二位金属切削过程模型,通过采用粘结.滑移摩擦模型,有效地模拟了航空钛合金的切削加工过程,对此类材料加工的切削力、切屑温度以及应力场和应变的分布进行了分析。 相似文献
18.
A nonlinear model of wave cutting is presented. Orthogonal cutting conditions are assumed. Effects of the cutting velocity on the mean friction coefficient are accounted for. An approximate analytical solution of the nonlinear problem is obtained. It is shown that for some supercritical conditions, corresponding to linear instability, the amplitude of vibrations saturates and decreases in the nonlinear analysis. A study of the influence of different parameters (friction, ploughing force, cutting velocity, etc.) on the linear and nonlinear stability results is developed. 相似文献
19.
A thermo-elastic–viscoplastic model using explicit finite element code Abaqus was developed to investigate the effect of sequential cuts and tool–chip friction on residual stresses in a machined layer. Chip formation, cutting forces and temperature were also examined in the sequential cuts. The affected layer from the first cut slightly changes the chip thickness, cutting forces, residual strain and temperature of the machined layer, but significantly affects the residual stress distribution produced by the second cut. Residual stress is sensitive to friction condition of the tool–chip interface. Simulation results offer an insight into residual stresses induced in sequential cuts. Based on simulation results, characteristics of residual stress distribution can be controlled by optimizing the second cut. 相似文献