The Development Of The CAPP System For Flashless Forging Of Gear Blanks And Its Optimization Design Of Forging Die Structure

Developed on the basis of Windows, the flashless forging CAPP system for gear blanks takes AutoCAD 2002 as pattern supporting software, and VBA embedded in AutoCAD 2002 as secondary developing tool. Drawings created by employing AutoCAD ActiveX technology. Technologic databases are managed by Microsoft Access. System interfaces are designed by adopting VBA language. And the above three are organically combined. After perfecting the structure and function of the system, optimization design of forging die structure are widely studied.By adjusting system interfaces, the paper makes gear blank information input and process parameters choice accord process flow and design thought of designer.By controlling the positive sign and minus of the gear blank input dimension, system realizes the versatility anddiversity.The calculation of processing parameters such as heating-up time and deformation resistance are discussed in the thesis.The paper makes use of axis symmetry of gear blank forging die, and realizes the die parameter design.During die design, considering the importance of universalization, standardization and seriation of die, cavity die adopts combination die and makes pre-stress ring fix on the die sets. To the same ton, the inside and outside diameters of pre-stress ring are the same, and the fixation of the punch and die set are also the same. When different forgings are produced, only die plate insertion and free part are designed. The universalization, standardization and seriation of die are the basis on die parameter.By improving on and renewing the CAPP system of the gear blank forging die, we have more perfect system. It mainly includes the input of the information about gear blanks, shape optimization, process planning design, the formation of parts, forging drawings and process cards, the establishment of technologic databases, the optimization of die structures and the formation of die drawings. The system has such functions as confirming and modifying forging parameters through the interaction between human beings and computers, forming process cards and optimizing die structures automatically,plotting forging and die drawings by parameters.The paper can approximately consider flashless forging as extrusion, and set up the mechanical mold of cavity die enduring inside press. The paper applying the cylinder intension theory, analyse the stress and formation of combination die, and optimise the structure of die.The system has many advantages such as having friendly interface, strong practicability, the normalization and standardization of die design. The successful development of the system to expand the fine forging process of gear blank, alleviate to the heavy labor of designer, shorten process design time and guarantee the quantity of the process design have the obvious significance.