Development And Realizm Of System For Parameterized Design And Unfolding Of Sheet Metal Of Pipes

In the modern industry, the manufacturing of sheet metal has played a more and more important role in chemical engineering, mechanism, and metallurgy and also light industry as well, in which the unfolding of sheet metal is an important link. In company with the advancement and development of scientific technology, the unfolding of sheet metal is used more and more widely in projects.According to the demands of production, a strongly functional system has been developed which is based on the platform of UG, aiming at the design and unfolding of sheet metal of pipes, taking the use of mathematic theory and computer technology. In the developing process, some study in the theory at the technology problems has also been done.The system concludes sixteen types of general sheet metal parts, and four types of which such as T-cylinder pipe, Ellipse-ellipse-mouth transformed pipe, Same-diameter curved-pipe and Gradually-smaller-diameter curved-pipe's design and unfolding are mainly realized.By entering parameters, the correspondent three-dimensional parameterized solid models can be created, and on the basis of which the two-dimensional unfolding view is also created utilizing structural dimension of the model and precise analytic method as well.For facilitating the uses of applicants, visualized graphic interfaces in the steps of type selection, parameter entering, and unfolding-pipe selection are designed; in the process of parameterization, constraint relations of correspondent model have been taken into consideration, making sure of the rationality of models; as the impact created by the thickness of sheet metal has been taken into consideration precisely, making sure of the geometry precision of the interface, which is also making the unfolding sheet fulfill the geometrical requirements of designing in the projects, therefore the parameterized design of three-dimensional models and two-dimensional unfolding view have been realized; the bend line number and unfolding location can be selected while unfolding pipes, adapted to the requirement of different dimension, different precision and different usability; the unfolding results can be output in the form of graphics and texts, which concludes additional information in geometry and physical such as area, mass, etc.The software of UG NX4.0 is taken as platform, in the use of the redevelopement tools such as UG/Open MenuScript, UG/Open UIStyler, UG/Open API and VC++6.0 programming language orientating objects, a system of parameterized designing and unfolding of sheet metal of pipes has been set up and developed.Some critical problems in theory and technology have been solved during the study and realization of the subject, in which some study is innovative. Such as, sheet metal systems which joins model design and surface unfolding are very rare nationwide; abstaction of interface spline and mapping to the middle layer in order to get the precise template curved face in modeling, and then adding thickness into it, has largely improved the precision of models and unfolding view; suface of transformed pipe is set into convolute suface which is unfoldable in order to decrease unfolding error; and the universal bend line construction and analytic equations has been deduced for the first time; the rule of transition point location when cone pipe joins with flat sheet has been verified and then been used in the model construction of cone-curved-pipe.In the manufacturing industry, sheet metal products are used more and more widely as the high effiency, low costs and simply craft of its production. There is still large development space for computer aided systems to design and unfold sheet metals. The developing work of system in the subject pushed it and possesses applicable value. The study such as abstraction of interface curve has a lot of theorical significance.