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工艺参数对316不锈钢粉末激光烧结温度场的影响 总被引:1,自引:1,他引:0
以有限元分析软件ANSYS为平台,对316不锈钢粉末激光烧结温度场分布进行了数值模拟.在考虑了材料的热物性参数随温度变化以及相变潜热等非线性情况下,建立了选择性激光烧结(SLS)三维有限元模型,利用ANSYS参数化设计语言APDL控制激光热源的热流密度、移动速度以及扫描路径,研究了工艺参数(激光功率、扫描速度、预热温度)对316不锈钢金属粉末成型过程中熔池及温度场分布产生的影响.模拟结果与前人文献实验结果相吻合,表明可以利用本模型对工艺参数进行优化,为实验工艺参数选取提供了理论依据. 相似文献
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《组合机床与自动化加工技术》2019,(7)
为了减小选择性激光熔化过程中的能量消耗,建立三维瞬态温度场模型,设置激光功率为2000W、光斑半径为4mm、扫描速度30mm/s;对单烧结道截面温度场进行研究,经过ANSYS仿真和MATLAB分析得到温度在径向深度方向呈高斯分布、径向宽度方向呈指数分布规律,在保证成型件质量的前提下结合最小能耗原则得出扫描间距为1.3mm;最后通过双烧结道的温度场模拟验证扫描间距设置的合理性,并通过相邻烧结道熔池截面模型确定铺粉层高为0.17mm,为选择性激光熔化过程中考虑能量消耗条件下的工艺参数优化提供了一种方法。 相似文献
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基于分形扫描的TC4合金激光立体成形研究 总被引:1,自引:0,他引:1
对分形扫描方式在TC4合金激光立体成形中的应用展开实验研究,探讨了分形扫描路径的成形特点,研究了激光立体成形工艺参数(激光功率、搭接率等)对TC4合金成形质量的影响,提出了分形扫描方式下消除熔合不良和孔洞的方法.研究发现,分形扫描方式下,TC4合金成形的主要缺陷为熔合不良和孔洞,其主要原因是分形路径拐弯处的沉积高度大于直线扫描时的沉积高度,从而使成形表面出现凹点;且随着激光功率的增加、搭接率的提高,TC4合金成形件的熔合不良和孔洞缺陷有所缓解,但是仍较明显.根据上述研究结论和分形扫描方式的成形特点,提出了"半光斑抖动"策略,即每层扫描起始点沿x、y方向偏移半个激光光斑,从而使上下两个沉积层形成的凹凸点相互叠加,有效地防止了成形表面质量的恶化. 相似文献
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目的 研究新型扫描策略,减小激光熔化沉积过程中基材的变形。方法 首先,采用分形曲线作为全域扫描策略,通过激光熔化沉积试验研究了1种传统扫描策略与3种分形扫描策略的基板变形。其次,提出将分形扫描策略和分区扫描策略相结合,按照分形曲线的走向扫描各个分区,形成基于分形曲线的分区扫描策略,通过激光熔化沉积试验研究了1种传统分区扫描策略与3种基于分形曲线的分区扫描策略的基板变形。结果 无论是全域扫描还是分区扫描,基板的4条边均发生了竖直向上的翘曲变形。在扫描路径的终点附近,基板的变形量最大。全域扫描策略下,基板的最大变形量分别为:光栅式扫描7.5mm,Peano曲线3.3 mm,Sierpinski曲线2.5 mm,Lebesgue曲线3.8 mm。分区扫描策略下,基板的最大变形量分别为:光栅式顺序7.5 mm,Hilbert曲线顺序3.5 mm,Sierpinski曲线顺序3.2 mm,Lebesgue曲线顺序5.4 mm。结论 基于分形曲线的分区扫描策略可以显著减小基板变形,还可以灵活地调节扫描线段的方向和数量,在综合考虑扫描线设计的灵活性和变形量的情况下,基于Sierpinski曲线的分区... 相似文献
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针对金属薄膜加工中材料热变形大、加工质量差等问题,提出基于纳秒激光的微加工技术。对激光加工汽化机制及热传导理论进行分析;以铝箔为例建立ABAQUS本构模型,对其热变形规律进行仿真分析;基于纳秒激光实验台对钛合金薄膜进行刻划实验,研究不同加工参数对工件表面质量的影响规律。结果表明:在激光加载初期,脉冲激光对材料汽化作用较为明显;随着激光加载时间的延长,热影响区域逐渐增大;沟槽深度随着热源移动速度的增加而逐渐降低,随着激光功率的增加而逐渐变大;仿真和实验结果的平均误差不超过5%。研究结果有助于纳秒激光加工技术的发展。 相似文献
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FEM SIMULATION FOR LASER FORMING PROCESSING 总被引:1,自引:0,他引:1
L.O.Li Y.B.Chen X.Y.Wang S.Y.Lin 《金属学报(英文版)》2004,17(3):317-322
Laser forming involves heating sheet metal workpiece along a certain path with a defocused laser beam directed irradiate to the surface. During laser forming, a transient temperature fields is caused by the irradiation and travelling of a laser beam. Consequently, thermal expansion and contraction take place, and allows the thermalmechanical forming of complex shapes. This is a new manufacturing technique that forming metal sheet only by thermal stress. Therefore, the analysis of temperature fields and stress fields are very useful for studying the forming mechanism and controlling the accuracy of laser forming. The non-liner finite element solver, MARC, is employed to solve the thermal-mechanical analysis. Using this model, the stress and strain distribution of pure aluminum plate with different thickness are analyzed. The influence of scanning speed on temperature fields and plastic strain of metal sheet under the condition of constant line energy are also presented. Numerical results agree well with the exT~erimental results. 相似文献
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以"飞思卡尔杯"智能车比赛为应用平台,以微控制器MC9s12xs128为核心单元,设计一套通过激光传感器实现路径识别的智能寻迹小车系统,利用模糊算法和过滤处理找出路径位置和方向,采用PD控制策略对小车运行进行控制。硬件设计包括信号调理电路、电源和电机驱动的设计等。实验结果证明,按该方案设计的智能车能够快速稳定运行。 相似文献
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曲面塑料模具激光熔覆再制造快速加工路径生成方法 总被引:1,自引:0,他引:1
对于曲面塑料模具,在其表面快速生成激光熔覆加工路径非常困难。针对这种情况,直接以零件的逆向点云模型为研究对象,通过平面与点云求交得到以密集离散点表示的近似激光扫描路径,避免了反求建模的过程。以离焦量变化极限为约束条件,在路径上搜索插补点。提出利用插补点的最近点来计算插补点曲面法向矢量作为激光束姿态的近似快速算法。应用镍基自熔性合金粉对P20材质的模具零件曲面表面进行了试验。金相分析表明所形成熔覆层组织均匀、致密,缺陷稀少;熔覆层与基体之间形成冶金结合。熔覆层中部组织出现了垂直于界面生长的柱状树枝晶,而在顶部许多的柱状树枝晶发育成等轴树枝晶。熔覆层的平均显微硬度达到330~350 HV0.2。路径中段的熔覆层厚度比起始点增加了10%。 相似文献
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A computer-aided planning method for laser scanning based on the CAD model has been developed. It integrates three planning criteria, visibility, accuracy, and efficiency and detects deep concave features that would be more suitable for CMM probing. Clustering, based on the view angle and depth of view, is used to plan an optimal scanner placement and motion path. Simulation studies on complex auto-parts demonstrate the effectiveness of the generated plans. The integration of the scanning plan with CMM controls was also demonstrated. The benefits of the CAD-based automated laser inspection planning have been demonstrated. 相似文献
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Félix A. España 《Surface & coatings technology》2010,204(15):2510-2517
Brass coating was applied to AISI410 steel using high power laser in a laser engineered net shaping (LENS™) system. The influence of laser treatment on interfacial microstructure and thermal performance was evaluated as a function of coating thickness. Laser deposition resulted in a diffused and metallurgically sound interface between metallurgically incompatible brass coating and AISI410 steel substrate. The thermal conductivity of AISI410 steel increased from 27 W/mK to a maximum of 37 W/mK depending on the coating thickness, almost 50% gain. The absence of sharp interface between the coating and the substrate, as a result of laser processing, resulted in a low interfacial thermal contact resistance. Thermal performance tests showed that the brass coating can enhance the heat transfer rate of stainless steel substrate. These results show that novel and efficient feature based coatings can be exploited using laser-based advanced manufacturing technologies for various industrial applications. 相似文献
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《Science & Technology of Welding & Joining》2013,18(3):352-357
AbstractUsing laser scanning techniques, scanning lens rotating around a laser diode and a circular laser trajectory was projected onto the surface of a weldment to detect it. Furthermore, one novel vision sensor based on the circular laser is developed. The three-dimensional (3D), circular laser based seam location sensor is investigated. On the basis of the light path system, 3D calculation algorithm is brought forward and used to locate the welded joint. After image denoise, filter, segmentation and thinning, characteristic points of the welded joint could be detected real time using a proposed vision sensor and confirmed by real experiments of butt welded joints with I groove and V groove, and lap, and fillet and ramp welded joints. The results show that circular laser based vision sensor can be used in seam locating and its calculation precision meets the requirement of seam tracking. 相似文献
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推导了恒定激光脉冲激励作用下的焊点瞬态热平衡方程,及基于极限温差反问题识别的缺陷尺寸及热阻解析求解方法;通过建立空洞缺陷焊点数字化模型,对恒定激光脉冲激励过程进行了热分析仿真,得到了焊点温差、热阻及缺陷尺寸之间的演化规律;通过制备虚焊缺陷焊点试验样本,实施了不同温度参数组合下的热试验,并对热试验后的焊点缺陷演化情况进行红外测温分析.试验结果表明,热试验过程中的焊点缺陷演化机理具有与金属材料蠕变曲线相似的变化规律,缺陷尺寸呈现先增大、后减小及再增大的变化行为,有助于完善和补充焊点的热试验理论. 相似文献