Multi-point forming (MPF) is an advanced manufacturing technology for three-dimensional sheet metal parts. In this paper, the MPF integrated system is described that can form a variety of part shapes without the need ...Multi-point forming (MPF) is an advanced manufacturing technology for three-dimensional sheet metal parts. In this paper, the MPF integrated system is described that can form a variety of part shapes without the need for solid dies, and given only geometry and material information about the desired part. The central component of this system is a pair of matrices of punches, and the desired discrete die surface is constructed by changing the positions of punches though the CAD and control system. The basic MPF process is introduced and the typical application examples show the applicability of the MPF technology. Wrinkle and dimple are the major forming defects in MPF process, numerical simulation is a feasible way to predict forming defects in MPF. In conventional stamping, the mode to form sheet metal with blankholder is an effective way to suppress wrinkling; the same is true in MPF. A MPF press with flexible blankholder was developed, and the forming results indicated the forming stability of this technique. Based on the flexibility of MPF, varying deformation path MPF and sectional MPF were explored that cannot be realized in conventional stamping. By controlling each punch in real-time, a sheet part can be manufactured along a specific forming path. When the path of deformation in MPF is designed properly, forming defects will be avoided completely and lager deformation is achieved. A work piece can be formed section by section though the sectional MPF, and this technique makes it possible to manufacture large size parts in a small MPF press. Some critical experiments were performed that confirmed the validity of two special MPF techniques.展开更多
In this paper, the principle of multi-point forming (MPF) technique is presented. One of the most serious defects, wrinkling, during the multi-point forming process of a shallow rectangle cup is discussed by means of ...In this paper, the principle of multi-point forming (MPF) technique is presented. One of the most serious defects, wrinkling, during the multi-point forming process of a shallow rectangle cup is discussed by means of numerical simulation on the shallow rectangle cup forming process. The effects of thickness, material of sheet metal and the pressure of the blank holder are investigated. Based on the simulation results, the reasons and control methods of wrinkling are pointed out. Moreover, the experiment on the multi-point die forming of the shallow rectangle cup by the MPF machine is done to validate the efficiency of the numerical simulation, and the result proves that the application of an elastic cushion in the forming can restrain wrinkling efficiently.展开更多
To apply the multi-point forming technology to the field of tube processing,the process of multi-point forming for tube is studied.Numerical simulation for the process of multi-point forming for tube is achieved by us...To apply the multi-point forming technology to the field of tube processing,the process of multi-point forming for tube is studied.Numerical simulation for the process of multi-point forming for tube is achieved by using elastic-plastic FEM in ABAQUS.During simulation,reasonable coefficient of mass scaling and friction model of penalty function are used.The influence of several major technological parameters on the process is analyzed.When the tube diameter is 60 mm and the forming curvature radius is 1000 mm,the distortion rate of cross-section and the absolute forming error gradually decrease with the increasing of tube wall thickness;However,when the tube wall thickness is constant,the smaller the curvature radius,the larger the distortion rate of cross-section,but as to forming part,its absolute forming error becomes smaller.展开更多
To improve the quality of multi-point die forming, a new approach using discrete steel pads was proposed. The formability of three different multi-point die forming processes was analyzed through numerical simulation ...To improve the quality of multi-point die forming, a new approach using discrete steel pads was proposed. The formability of three different multi-point die forming processes was analyzed through numerical simulation and experiments. Numerical simulation and experimental results showed that the use of discrete steel pads in the multi-point forming process can substantially improve the stress–strain state on the plate and suppress dimple, straight-edge, and wrinkle defects. This analysis verified that the use of discrete steel pads in a multi-point forming process can effectively improve the quality and accuracy with which sheet metal is formed.展开更多
This paper considers a cold standby repairable system consisting of twosupplemental equipments and a single repoirman. In the system, the failure distribu-tions and repair distributions of the two-supplemental equipme...This paper considers a cold standby repairable system consisting of twosupplemental equipments and a single repoirman. In the system, the failure distribu-tions and repair distributions of the two-supplemental equipments are assumed to beexponential distributions, but one supplemental equipment after repair will be “asgood as new” and the other one not. Under these assumptions, seme reliability in-dices are derived by using the geometric process and the method of supplementaryvariable.展开更多
目的为了提高纸质医疗设备质控检测原始记录表手写数据的电子化录入效率,替代传统手工录入方式,实现手写检测数据的批量化自动录入。方法基于Python语言,开发一套基于深度学习光学字符识别(Optical Character Recognition,OCR)的医疗设...目的为了提高纸质医疗设备质控检测原始记录表手写数据的电子化录入效率,替代传统手工录入方式,实现手写检测数据的批量化自动录入。方法基于Python语言,开发一套基于深度学习光学字符识别(Optical Character Recognition,OCR)的医疗设备质控检测原始数据记录表智能识别系统。深度学习OCR技术采用百度智能云OCR云服务,实现批量识别质控检测记录表电子图片,获取结构化的检测数据识别结果,并将识别结果以电子表格的形式导出。结果该系统已实现8种常用医疗设备质控检测原始记录表的智能化识别,经实验测试,8种质控检测记录表平均识别耗时为5.45 s,平均识别正确率为95.94%。系统应用后,医疗设备质控检测原始记录表手写数据电子化录入用时显著低于传统手工录入方式,且差异有统计学意义(P<0.001)。结论该系统识别速度快,识别正确率高,实现了医疗设备质控检测原始记录表批量化、智能化、电子化自动录入,节省了大量人力,提高了质控检测数据整理效率,为质控检测数据的深度分析打下坚实基础。展开更多
文摘Multi-point forming (MPF) is an advanced manufacturing technology for three-dimensional sheet metal parts. In this paper, the MPF integrated system is described that can form a variety of part shapes without the need for solid dies, and given only geometry and material information about the desired part. The central component of this system is a pair of matrices of punches, and the desired discrete die surface is constructed by changing the positions of punches though the CAD and control system. The basic MPF process is introduced and the typical application examples show the applicability of the MPF technology. Wrinkle and dimple are the major forming defects in MPF process, numerical simulation is a feasible way to predict forming defects in MPF. In conventional stamping, the mode to form sheet metal with blankholder is an effective way to suppress wrinkling; the same is true in MPF. A MPF press with flexible blankholder was developed, and the forming results indicated the forming stability of this technique. Based on the flexibility of MPF, varying deformation path MPF and sectional MPF were explored that cannot be realized in conventional stamping. By controlling each punch in real-time, a sheet part can be manufactured along a specific forming path. When the path of deformation in MPF is designed properly, forming defects will be avoided completely and lager deformation is achieved. A work piece can be formed section by section though the sectional MPF, and this technique makes it possible to manufacture large size parts in a small MPF press. Some critical experiments were performed that confirmed the validity of two special MPF techniques.
文摘In this paper, the principle of multi-point forming (MPF) technique is presented. One of the most serious defects, wrinkling, during the multi-point forming process of a shallow rectangle cup is discussed by means of numerical simulation on the shallow rectangle cup forming process. The effects of thickness, material of sheet metal and the pressure of the blank holder are investigated. Based on the simulation results, the reasons and control methods of wrinkling are pointed out. Moreover, the experiment on the multi-point die forming of the shallow rectangle cup by the MPF machine is done to validate the efficiency of the numerical simulation, and the result proves that the application of an elastic cushion in the forming can restrain wrinkling efficiently.
基金Sponsored by the Specific Targeted Research Projects,the 6th Framework Project,EU(Grant No.AST5-CT-2006-030877)
文摘To apply the multi-point forming technology to the field of tube processing,the process of multi-point forming for tube is studied.Numerical simulation for the process of multi-point forming for tube is achieved by using elastic-plastic FEM in ABAQUS.During simulation,reasonable coefficient of mass scaling and friction model of penalty function are used.The influence of several major technological parameters on the process is analyzed.When the tube diameter is 60 mm and the forming curvature radius is 1000 mm,the distortion rate of cross-section and the absolute forming error gradually decrease with the increasing of tube wall thickness;However,when the tube wall thickness is constant,the smaller the curvature radius,the larger the distortion rate of cross-section,but as to forming part,its absolute forming error becomes smaller.
文摘To improve the quality of multi-point die forming, a new approach using discrete steel pads was proposed. The formability of three different multi-point die forming processes was analyzed through numerical simulation and experiments. Numerical simulation and experimental results showed that the use of discrete steel pads in the multi-point forming process can substantially improve the stress–strain state on the plate and suppress dimple, straight-edge, and wrinkle defects. This analysis verified that the use of discrete steel pads in a multi-point forming process can effectively improve the quality and accuracy with which sheet metal is formed.
文摘This paper considers a cold standby repairable system consisting of twosupplemental equipments and a single repoirman. In the system, the failure distribu-tions and repair distributions of the two-supplemental equipments are assumed to beexponential distributions, but one supplemental equipment after repair will be “asgood as new” and the other one not. Under these assumptions, seme reliability in-dices are derived by using the geometric process and the method of supplementaryvariable.
文摘目的为了提高纸质医疗设备质控检测原始记录表手写数据的电子化录入效率,替代传统手工录入方式,实现手写检测数据的批量化自动录入。方法基于Python语言,开发一套基于深度学习光学字符识别(Optical Character Recognition,OCR)的医疗设备质控检测原始数据记录表智能识别系统。深度学习OCR技术采用百度智能云OCR云服务,实现批量识别质控检测记录表电子图片,获取结构化的检测数据识别结果,并将识别结果以电子表格的形式导出。结果该系统已实现8种常用医疗设备质控检测原始记录表的智能化识别,经实验测试,8种质控检测记录表平均识别耗时为5.45 s,平均识别正确率为95.94%。系统应用后,医疗设备质控检测原始记录表手写数据电子化录入用时显著低于传统手工录入方式,且差异有统计学意义(P<0.001)。结论该系统识别速度快,识别正确率高,实现了医疗设备质控检测原始记录表批量化、智能化、电子化自动录入,节省了大量人力,提高了质控检测数据整理效率,为质控检测数据的深度分析打下坚实基础。
