共查询到20条相似文献,搜索用时 52 毫秒
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通过对几种典型零件在切割过程中的热应力分析,特别是对采用多割嘴(三只或四只)同时切割的分析,表明产生切割变形的主要原因是合应力的作用。分析合应力,找出影响零件尺寸精度的主要因素,改进切割程序,达到了控制切割变形的目的。 相似文献
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采用等离子切割钢板时,由于等离子切割弧的形状不规则,在切割过程中等离子弧并不垂直于钢板表面,钢板上层先于下层被切割,直角零件常被切割成圆角零件,导致零件切割质量不合格。现对原有工艺进行改善,等割零件一次交检合格率提升至95%,减少了手工打磨时间,零件生产效率提高20%。 相似文献
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全自动等离子切割凭借其高效、切割成型好、对操作者技能要求低等特点,在桥梁、锅炉容器、船舶等钢结构工程建设中得到越来越广泛的应用.为此针对某产品通风筒进行了大量的调研和全自动等离子切割试验,较全面的掌握了1 mm薄壁管件的等离子切割技术,保证了某产品通风筒的制造质量. 相似文献
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针对包含桥连接的钣金切割件加工路径问题,提出基于旅行商问题模型的钣金件切割路径优化方法,并确定了该方法下桥连接的定位。此方法针对钣金排样图,将轮廓基于图元特征拆分成Ni段子轮廓段加工图元,以遍历所有子轮廓段为目标规划切割路径,采用改进的蚁群算法获得包含桥连接定位点的切割路径,最后依据桥连接定位点确定全体桥连接位置。对排样好的钣金切割件进行仿真验证,并将含桥连接的传统广义旅行商问题切割方法与相关文献方法进行对比,表明了该方法能够有效地减少切割空程路径及切割过程中的启停次数,提高了加工效率。 相似文献
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A new theory to determine the dynamic cutting coefficients from steady state cutting data for three dimensional cutting has been developed. It is based on direct measurements of cutting forces, without any hypothesis relating to the steady state cutting. The experimental results show fairly good coincidence with the theoretical prediction of the stability limit. 相似文献
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This paper uses the large deformation large strain finite-element theory, the updated Lagrangian formulation and the incremental theory approach to develop a 3D elastic-plastic analytical model that examines metal cutting on the tool tip and twin nodes on the machined face. The geometric position and the critical value of strain energy density, combined with twin node treatment, are also introduced to serve as the continuous chip separation criterion.
Finally, the 3D low-velocity cutting condition of mild steel was explored to analyze changes in the appearances of the workpiece and the chip, the distribution of stress and strain, and the progress of changes in the cutting force. The impact of different cutting velocities and the initial conditions of the residual stress were studied to understand the impact of various cutting conditions on the machined workpiece. The numerical average cutting forces are compared with the experimental cutting forces with the different low-cutting velocities to verify that the 3D cutting model that has been developed is reasonable. 相似文献
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《International Journal of Machine Tool Design and Research》1977,17(4):225-234
The paper contains an analysis of orthogonal cutting where process geometry is described by the chip compression factor λ and where friction of the rake face is determined by the reduced tool-chip contact length n. The minimum energy principle is applied to a simple upper-bound field and an analytical relationship is found between λ and n. Experimental results, together with data from literature, are compared with the theoretical expression, and the range of validity of the model is discussed. The same model is proposed to explain the action of cutting fluids, a particular feature of the model being that fluid access to the rake face is not required. Three different mechanisms are suggested to account for lubrication in cutting, which generally speaking consists in restriction of the tool-chip contact area. It is proposed to adopt the reduced contact length in efficiency tests for cutting fluids. Experimental results are presented. 相似文献
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Cutting force modeling is a major discipline in the research of cutting processes. The exact prediction of cutting forces is crucial for process characterization and optimization. Semi-empirical and mechanistic force models have been established, but the identification of the specific cutting force for a pair of tool and workpiece material is still challenging. Existing approaches are depending on geometrical idealizations and on an extensive calibration process, which make practical and industrial application difficult. For nonstandard tools and five axis kinematics there does not exist a reasonable solution for the identification problem.In this paper a co-operative force model for the identification of the specific cutting forces and prediction of integral forces is presented. The model is coupled bidirectionally with a multi-dexel based material removal model that provides geometrical contact zone information. The nonlinear specific forces are modeled as polynomials of uncut chip thickness. The presented force model is not subjected to principal restrictions on tool shape or kinematics, the specific force and phase shift are identified with help of least square minimization. The benefit of this technique is that no special calibration experiments are needed anymore, which qualifies the method to determine the specific forces simultaneously during the machining process. In this paper, experiments with different cutting conditions are analyzed and systematically rated. Finally, the method is validated by experiments using different cutting conditions. 相似文献
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SeongMin Son HanSeok Lim JungHwan Ahn 《International Journal of Machine Tools and Manufacture》2006,46(15):2066-2072
In the ultra-precision diamond cutting process, the rake angle of the tool becomes negative because the edge radius of a tool is considerably larger compared to the sub-micrometer depth of the cut. The effects of plowing due to the large negative rake angle result in an unstable cutting process without continuous chip. For this reason, it is important to determine minimum cutting thickness in order to enable greater machining accuracy to be obtained by fine and stable machining. It was previously reported that the critical depth of cut with a continuous chip was determined by the tool sharpness and the friction coefficient between a workpiece and a tool [S.M. Son, et al., Effects of the friction coefficient on the minimum cutting thickness in micro cutting, International Journal of Machine Tools and Manufacture 45 (2005) 529–535]. For the same edge radius of a tool, the higher the friction coefficient of the tool–workpiece, the thinner the minimum cutting thickness becomes. Therefore, it is believed that increasing the friction coefficient by a physical method would be effective to achieve thinner stable cutting. In this study, the possibility of reducing the minimum cutting thickness was investigated through changing the friction coefficient of a tool–workpiece. The vibration cutting method is applied to increase the friction coefficient. Experimental results show that the cutting technology is efficient for increasing the friction coefficient and decreasing the minimum cutting thickness. The minimum cutting thickness was reduced by about 0.02–0.04 μm depending on materials and vibration conditions. 相似文献
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切管机是管材加工及应用行业的专用加工设备,管材的管-板相贯的几何特点给切割一次成形带来了很大的困难,基于一次成形的考虑,提出了管-板相贯求交的一个通用算法,根据这一算法设计的数控切管机成功地实现了这类坡口一次数控切割成形,并通过一个较为典型的例子作一详细的论述. 相似文献
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切削温度与切削力综合测量的虚拟仪器 总被引:1,自引:1,他引:0
王细洋 《组合机床与自动化加工技术》2002,(12):52-54
介绍了综合测量切削平均温度和三向切削力并对其进行分析处理的虚拟仪器.利用PCI-1 200卡采集热电偶测温仪和电阻应变式测力仪传输的数据.利用LabVIEW平台开发.具有显示 力和温度波形曲线、热电偶标定和测力仪刻度标定、确定切削温度和切削力指数公式的能力 .提出了基于切削力和切削温度信息的切削状态判定方法. 相似文献