三维成形中空环形激光传输转换建模及光料耦合分析
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摘要
激光熔覆快速成形就是利用聚焦激光束与同步送入光斑的金属材料耦合进行三维立体成形的技术。目前此项技术中激光聚焦光斑普遍采用实心光斑,送料方式为单料管光外侧向送料或多料管光外包围同轴送料。在这种光源和送料方式下,光斑和熔覆材料的耦合稳定性比较差,造成成形过程不稳定,沉积率极低,冶金质量不高,加工件精度与粗糙度不理想。本文应用了一种新型的中空环形激光聚焦系统,并采用了光内同轴送料熔覆方式。本课题重点对这种中空环形激光束的传输转换、聚焦光斑的能量分布和光料耦合效应进行了研究。
运用几何光学,采用光线追迹法,建立了中空环形激光聚焦系统的光束转换聚焦模型,并模拟出了在不同离焦量横截面上聚焦光斑的能量分布。通过研究得出:光束在离焦|z|小于0.727mm时,聚焦光斑叠加为实心光斑,而在其它离焦量的横截面上均为中空环形光斑。中空环形激光聚焦光斑的能量密度呈“双峰形”分布,并推断出中空环形激光在扫描时线宽方向上吸收的光能呈“马鞍形”分布。同时得出了不同离焦量横截面上中空环形光斑的大小和占空比之间的关系。
利用中空环形激光光内同轴送料熔覆方式进行了扫描方向性试验,并分别进行光内送粉和光内送丝的单道熔覆以及三维成形试验。试验证明:中空环形光光内同轴送料熔覆实现了光料真正意义上的同轴,光料能够准确的耦合,完全消除了扫描方向性对熔覆质量的影响。中空环形聚焦光斑扫描线宽方向上吸收光能的“马鞍形”分布与实心光斑的“高斯形”分布相比,不仅减小了熔池的能量密度梯度,而且为熔道侧面提供了更多的能量,减小了实心光斑熔覆时边缘能量不足对熔道侧面的影响。对成形件进行分析可知,成形件表面光洁,与基体形成了致密的冶金结合,微观组织晶粒细小、均匀,无杂质、气孔等缺陷。
Laser cladding rapid prototyping is a technique which coupling the focused laser beam and the metal materials which enter into the spot simultaneously to Three-Dimensional Prototyping. But now the solid focused laser spot is commonly used in this technology, and the type of material feeding is the lateral material feeding or coaxial material feeding outside the laser. Under this laser spot and material feeding method, the stability of the coupling performance of the laser spot and the cladding material is very poor, which leads to the instability of the prototyping process, the very low metallurgical quality and the nonideal precision and the roughness of the work pieces. This paper uses a new type of hollow circular focusing system and adopted a method of inside-laser coaxial material feeding to clad. Paying heavy stress on the transmission conversion of this hollow circular laser and the coupling between optical and material.
Using geometrical optics and ray tracing method, this paper establishes the hollow circular laser beam focusing system conversion model and simulates the energy distribution of the focused spot at different defocusing cross section. According to the research,the conclusiones can be geted as flollowing: when|z| is littler than 0.727mm,the focusing laser is solid spot, but it is hollow circular spot at the other defocusing cross sections. The energy distribution of the hollow circular laser beam is“bimodal-shape”, according to which we can deduce that the energy absorbed at the scan direction of the hollow circular laser is“saddle-shape”. At the same time we can get the relationship between hollow circular laser beam and duty circle at different defocusing cross section.
This paper uses the approach of inside-laser coaxial material feeding cladding with the hollow circular laser to do the scanning direction test, and do the inside-laser coaxial power feeding cladding and inside-laser coaxial wired feeding cladding separately.It is proved that:the inside-laser coaxial material feeding cladding can achieve a real coaxial of the laser material,the optical and material can coupe accurately, eliminating completely the impaction of the scanning direction to the cladding quality. Compared with the“Gaussion-shape”of solid spot, the“Saddle-shape”distribution of the energy absorbed at the scan dirction of the hollow circular laser not only reduces the energy density gradient of the pool, but also provides more energy to the melting road side,and reduces the bad impact on melting road side caused by the shortage of the energy of the edge of the solid laser spot.Through anglicizing the prototyping modeling it is concluded that:the prototyping modeling surface is very smooth and form the metallurgical combination with the bade,the microstructures are very small, even,without impurities, porosity and other defects.
运用几何光学,采用光线追迹法,建立了中空环形激光聚焦系统的光束转换聚焦模型,并模拟出了在不同离焦量横截面上聚焦光斑的能量分布。通过研究得出:光束在离焦|z|小于0.727mm时,聚焦光斑叠加为实心光斑,而在其它离焦量的横截面上均为中空环形光斑。中空环形激光聚焦光斑的能量密度呈“双峰形”分布,并推断出中空环形激光在扫描时线宽方向上吸收的光能呈“马鞍形”分布。同时得出了不同离焦量横截面上中空环形光斑的大小和占空比之间的关系。
利用中空环形激光光内同轴送料熔覆方式进行了扫描方向性试验,并分别进行光内送粉和光内送丝的单道熔覆以及三维成形试验。试验证明:中空环形光光内同轴送料熔覆实现了光料真正意义上的同轴,光料能够准确的耦合,完全消除了扫描方向性对熔覆质量的影响。中空环形聚焦光斑扫描线宽方向上吸收光能的“马鞍形”分布与实心光斑的“高斯形”分布相比,不仅减小了熔池的能量密度梯度,而且为熔道侧面提供了更多的能量,减小了实心光斑熔覆时边缘能量不足对熔道侧面的影响。对成形件进行分析可知,成形件表面光洁,与基体形成了致密的冶金结合,微观组织晶粒细小、均匀,无杂质、气孔等缺陷。
Laser cladding rapid prototyping is a technique which coupling the focused laser beam and the metal materials which enter into the spot simultaneously to Three-Dimensional Prototyping. But now the solid focused laser spot is commonly used in this technology, and the type of material feeding is the lateral material feeding or coaxial material feeding outside the laser. Under this laser spot and material feeding method, the stability of the coupling performance of the laser spot and the cladding material is very poor, which leads to the instability of the prototyping process, the very low metallurgical quality and the nonideal precision and the roughness of the work pieces. This paper uses a new type of hollow circular focusing system and adopted a method of inside-laser coaxial material feeding to clad. Paying heavy stress on the transmission conversion of this hollow circular laser and the coupling between optical and material.
Using geometrical optics and ray tracing method, this paper establishes the hollow circular laser beam focusing system conversion model and simulates the energy distribution of the focused spot at different defocusing cross section. According to the research,the conclusiones can be geted as flollowing: when|z| is littler than 0.727mm,the focusing laser is solid spot, but it is hollow circular spot at the other defocusing cross sections. The energy distribution of the hollow circular laser beam is“bimodal-shape”, according to which we can deduce that the energy absorbed at the scan direction of the hollow circular laser is“saddle-shape”. At the same time we can get the relationship between hollow circular laser beam and duty circle at different defocusing cross section.
This paper uses the approach of inside-laser coaxial material feeding cladding with the hollow circular laser to do the scanning direction test, and do the inside-laser coaxial power feeding cladding and inside-laser coaxial wired feeding cladding separately.It is proved that:the inside-laser coaxial material feeding cladding can achieve a real coaxial of the laser material,the optical and material can coupe accurately, eliminating completely the impaction of the scanning direction to the cladding quality. Compared with the“Gaussion-shape”of solid spot, the“Saddle-shape”distribution of the energy absorbed at the scan dirction of the hollow circular laser not only reduces the energy density gradient of the pool, but also provides more energy to the melting road side,and reduces the bad impact on melting road side caused by the shortage of the energy of the edge of the solid laser spot.Through anglicizing the prototyping modeling it is concluded that:the prototyping modeling surface is very smooth and form the metallurgical combination with the bade,the microstructures are very small, even,without impurities, porosity and other defects.
引文
[1]郑启光.激光先进制造技术[M].华中科技大学出版社.2001
[2]洪蕾,吴钢.激光制造技术基础[M].人民交通出版社.2008
[3]胡昌奎,陈培锋,黄涛.高功率激光加工中光束的转换、聚焦和整合[J].激光与光电子学进展,2004,41(2):53-56
[4]杨扬.CO2激光束几种聚焦方案的比较[J].激光杂志,1999,20(2):29-32
[5] Fang H T,Wu L.S..Research on digit technology applied to arnalyze cross-section intensity distribution of laser beam[J].Chinese Journal of Quantum Electronics,2003,20(4):508-512
[6] S.Sun,Y.Durandet,M.Brand.Parametric investigation of pulsed Nd:YAG laser cladding of stellite 6 on stainless steel.Surface&Coatings Technology,194(2005):225–231
[7]彭善飞.环形激光作用下同轴送粉熔覆工艺参数对成形的影响.苏州:苏州大学硕士论文.2008,5
[8]王小兵,孙斌等.定向棱镜腔平顶高斯激光束特性的研究.激光技术,2002,26(2):117—119
[9]王新洪,邹增大,曲仕尧.表面熔融凝固强化技术.化学工业出版社.北京.2005,(7):96-99
[10]王智勇,陈虹,左铁钏.一种大功率激光加工用带式积分镜的设计[J].北京工业大学学报.2009,28(3):334-336
[11]罗曦,陈培锋,王英,熊文策.一种大功率激光加工用新型宽带光斑成形抛物面镜[J].中国激光.2008,35(11):1853-1856
[12]杨洗陈,王云山,赵新,王宝琦.大面积激光自动涂敷系统及其工业应用.天津纺织工学院学报.1998,17(1):80-85
[13]杨洗陈,王宝琦,王云山,赵新.万瓦级激光熔敷宽带扫描转镜的研究.光电子激光.1996,7(5):279-282
[14]杨洗陈,王云山,孙荣禄.激光宽带淬火机理及应用研究.中国机械工程.2004,15(3):196-198
[15]陈鹤鸣,赵新彦.激光原理及应用[M].北京:电子工业出版社.2009
[16]陆璇辉,张蕾,薛大建,陈许.基于腔内变换的空心激光光束[J].激光与红外.2002,32(5):309-311
[17]印建平,刘南春,夏勇,恽曼.空心光束的产生及其在现代光学中的应用.物理学进展.2004,9:336-380
[18]左铁钏.21世纪的先进制造技术[M].北京:科学出版社.2007
[19]黄慧琴,赵承良,陆璇辉.空心光束的研究进展[J].激光与红外.2007,37(4):300-303
[20]张蕾,蔡阳健,陆璇辉.一种新空心光束的理论及实验研究[J].物理学报.2004,53(6):1777-1781
[21]汪治,李正直,田志伟.一种新型激光环形聚焦系统的研究[J].杭州大学学报.1996,23(3):235-240
[22] L.Sexton,S.Lavin,G.Byrne,A.Kennedy.Laser cladding of aerospace materials. Journal of Materials Processing Technology, 2002(122): 63-68
[23] A.Simchi,H.Pohl.Effects of laser sintering processing parameters on the microstructure and densification of iron powder.Materials and Engineering A359(2003):119-128
[24]杨国家.激光光内同轴送丝熔覆工艺研究[D].苏州:苏州大学硕士论文.2008
[25]王明娣.基于光内送粉的激光熔覆快速制造机理与工艺研究.南京:南京航空航天大学博士论文.2008,4
[26] Andrew J.Pinkerton, Lin Li.The significance of deposition point standoff variations in multiple-layer coaxial laser cladding (coaxial cladding standoff effects) International Journal of Machine Tools & Manufacture.44(2004) 573~ 584
[27] Fude Wang, J.Mei, Xinhua Wu. Microstructure study of direct laser fabricated. Ti alloys using powder and wire.Applied Surface Science, 2006 (253): 1424–1430
[28]石世宏,傅戈雁,王安军等.激光加工成形制造光内送粉工艺与送粉喷头.发明专利.专利号:CN 101148760A
[29]傅戈雁,石世宏,胡进等.激光光内送丝熔覆方法与光内送丝装置.发明专利.专利号:CN 101386111A
[30]陈虹.激光光束质量对光束传输聚焦和加工质量的影响[D].北京:北京工业大学博士论文,2006.4
[31]左铁钏.制造用激光—光束质量、传输质量与聚焦质量[M].北京:科学出版社.2008
[32]吕百达.激光光学—光束描述、传输变换与光腔技术物理[M].高等教育出版社.2003
[33]王庆峰.光束的聚焦特性和光谱特性研究[D].西南交通大学硕士论文.2006
[34]石世宏.激光加工技术讲义.苏州:2008
[35]胡家升.光学工程导论[M].大连理工大学出版社.2002
[36]萧泽新.工程光学设计[M].电子工业出版社.2002
[37]邵其文.基于光内送粉的激光熔覆快速成形技术研究.苏州:苏州大学硕士论文.2008,5
[38]姚纯.激光熔覆实体快速成形及送粉系统研究.苏州:苏州大学硕士论文.2006,5
[39]金岡優(日).激光加工[M].机械工业出版社.2005
[40]罗时荣.平顶分布光束的描述、计算模拟和基于强度矩方法的激光光束质量研究[D].四川大学博士论文,2003.10
[41]石世宏,傅戈雁,李龙,王永康.中空激光光内同轴送丝熔覆工艺的实现及其试验研究[J].中国激光.2010,37(1):266-270
[42]陈静,谭华,杨海欧,刘振侠,黄卫东.激光快速成形过程中熔池形态的演化[J].中国激光.2007,34(3):442-446
[43]张永康.激光加工技术[M].北京:化学工业出版社.2004
[44]杨毅.激光直接快速成形金属零件的机理及工艺研究[D].南华大学硕士论文.2006,5
[45] D Hu,H Mei and R Kovacevic. Improving solid freeform fabrication by laser based additive manufacturing. Proc Instn Mech Engrs Vol 216 Part B: J Engineering Manufacture B14001 I Mech E 2002
[46]郑启光.激光原理及应用[M].华中科技大学出版社.2001
[2]洪蕾,吴钢.激光制造技术基础[M].人民交通出版社.2008
[3]胡昌奎,陈培锋,黄涛.高功率激光加工中光束的转换、聚焦和整合[J].激光与光电子学进展,2004,41(2):53-56
[4]杨扬.CO2激光束几种聚焦方案的比较[J].激光杂志,1999,20(2):29-32
[5] Fang H T,Wu L.S..Research on digit technology applied to arnalyze cross-section intensity distribution of laser beam[J].Chinese Journal of Quantum Electronics,2003,20(4):508-512
[6] S.Sun,Y.Durandet,M.Brand.Parametric investigation of pulsed Nd:YAG laser cladding of stellite 6 on stainless steel.Surface&Coatings Technology,194(2005):225–231
[7]彭善飞.环形激光作用下同轴送粉熔覆工艺参数对成形的影响.苏州:苏州大学硕士论文.2008,5
[8]王小兵,孙斌等.定向棱镜腔平顶高斯激光束特性的研究.激光技术,2002,26(2):117—119
[9]王新洪,邹增大,曲仕尧.表面熔融凝固强化技术.化学工业出版社.北京.2005,(7):96-99
[10]王智勇,陈虹,左铁钏.一种大功率激光加工用带式积分镜的设计[J].北京工业大学学报.2009,28(3):334-336
[11]罗曦,陈培锋,王英,熊文策.一种大功率激光加工用新型宽带光斑成形抛物面镜[J].中国激光.2008,35(11):1853-1856
[12]杨洗陈,王云山,赵新,王宝琦.大面积激光自动涂敷系统及其工业应用.天津纺织工学院学报.1998,17(1):80-85
[13]杨洗陈,王宝琦,王云山,赵新.万瓦级激光熔敷宽带扫描转镜的研究.光电子激光.1996,7(5):279-282
[14]杨洗陈,王云山,孙荣禄.激光宽带淬火机理及应用研究.中国机械工程.2004,15(3):196-198
[15]陈鹤鸣,赵新彦.激光原理及应用[M].北京:电子工业出版社.2009
[16]陆璇辉,张蕾,薛大建,陈许.基于腔内变换的空心激光光束[J].激光与红外.2002,32(5):309-311
[17]印建平,刘南春,夏勇,恽曼.空心光束的产生及其在现代光学中的应用.物理学进展.2004,9:336-380
[18]左铁钏.21世纪的先进制造技术[M].北京:科学出版社.2007
[19]黄慧琴,赵承良,陆璇辉.空心光束的研究进展[J].激光与红外.2007,37(4):300-303
[20]张蕾,蔡阳健,陆璇辉.一种新空心光束的理论及实验研究[J].物理学报.2004,53(6):1777-1781
[21]汪治,李正直,田志伟.一种新型激光环形聚焦系统的研究[J].杭州大学学报.1996,23(3):235-240
[22] L.Sexton,S.Lavin,G.Byrne,A.Kennedy.Laser cladding of aerospace materials. Journal of Materials Processing Technology, 2002(122): 63-68
[23] A.Simchi,H.Pohl.Effects of laser sintering processing parameters on the microstructure and densification of iron powder.Materials and Engineering A359(2003):119-128
[24]杨国家.激光光内同轴送丝熔覆工艺研究[D].苏州:苏州大学硕士论文.2008
[25]王明娣.基于光内送粉的激光熔覆快速制造机理与工艺研究.南京:南京航空航天大学博士论文.2008,4
[26] Andrew J.Pinkerton, Lin Li.The significance of deposition point standoff variations in multiple-layer coaxial laser cladding (coaxial cladding standoff effects) International Journal of Machine Tools & Manufacture.44(2004) 573~ 584
[27] Fude Wang, J.Mei, Xinhua Wu. Microstructure study of direct laser fabricated. Ti alloys using powder and wire.Applied Surface Science, 2006 (253): 1424–1430
[28]石世宏,傅戈雁,王安军等.激光加工成形制造光内送粉工艺与送粉喷头.发明专利.专利号:CN 101148760A
[29]傅戈雁,石世宏,胡进等.激光光内送丝熔覆方法与光内送丝装置.发明专利.专利号:CN 101386111A
[30]陈虹.激光光束质量对光束传输聚焦和加工质量的影响[D].北京:北京工业大学博士论文,2006.4
[31]左铁钏.制造用激光—光束质量、传输质量与聚焦质量[M].北京:科学出版社.2008
[32]吕百达.激光光学—光束描述、传输变换与光腔技术物理[M].高等教育出版社.2003
[33]王庆峰.光束的聚焦特性和光谱特性研究[D].西南交通大学硕士论文.2006
[34]石世宏.激光加工技术讲义.苏州:2008
[35]胡家升.光学工程导论[M].大连理工大学出版社.2002
[36]萧泽新.工程光学设计[M].电子工业出版社.2002
[37]邵其文.基于光内送粉的激光熔覆快速成形技术研究.苏州:苏州大学硕士论文.2008,5
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