A Study On CAD/CAM System For NC Incremental Reverse Forming

The existing NC incremental reverse forming system can’t adapt to various experimentalmodels because of complexity of sheet shape and limitation of sheet depth. The study onrecognizing incision characteristics, filling holes, generating support automatically, generatingforming path, checking and eliminating interference and so on is not enough. For presentshortages, a series of algorithms were proposed to improve this system and make it adapt toforming requirement of various reverse forming sheet in this paper.Firstly, a method about recognizing incision characteristics applying to reverse formingwas presented for forming sheets with gaps. In the aspect of filling holes, a new method aboutcorrecting space surfaces was raised in order to obtain more accurate hole space surfacecharacteristics. Secondly, the method about solidifying support and manufacturing layeredmodel was proposed to solve the questions about manufacturing support during the reverseforming. Thirdly, contour forming path containing the coordinate and rotation angle of pathpoint was received for generating forming path of the press tool. Fourthly, a negative formingmethod based on sectioning sheet and support was proposed considering the questions such asthe length of press tool, the thickness of available support workblank, the depth of support die,interference between press tool and sheet. In order to verify the feasibility of this formingmethod, finite element analysis was applied respectively in the sectioned forming and thewhole forming in order to compare their forming accuracy. Finally, functions related to thesheet NC incremental reverse forming were gathered synthesizing these algorithms and usingVC++6.0，OpenGL and C language. A NC incremental negative forming CAD/CAM systemwith high availability was developed to demonstrate the functions of the whole formingprocess.