Research And Application Of Automatic Modeling Of Calibrator CAD Based On Feature Recognitions

The plastic profile is a kind of plastic products with irregular cross section.In recent years,it has been widely used in building materials and other industries.The plastic profile extrusion die is a kind of process equipment to produce plastic profiles.The calibrator is the main cooling and shaping structure of extrusion dies,which plays an important role in extrusion quality and extrusion efficiency.In this study,aimed at the problems such as the lack of experience in three-dimensional(3D)design theory,low design efficiency,non-standard drawings among three-dimensional model-to-engineering drawing,mass dimension work and so on,the automatic modeling method for calibrator CAD was researched and an automatic modeling system for calibrator CAD based on UG NX was developed.The research work of this paper is as follows(1)The research at home and abroad and application status of CAD technology of plastic profile calibrator were analyzed,the problems existing in the current design process were pointed out,the importance of improving the design level and the design efficiency of calibrators by the digital design method was expounded,and the purpose and significance of the research on automatic modeling of calibrator CAD were stated.(2)The automatic modeling method of calibrator 3D model is studied deeply.By analyzing the structure of calibrators,Aimed at the defects of the calibrator separate-design method,the whole-design method is studied.The calibrator design was divided into the cavity,parting,mold-base,water channels,gas channels,etc.An automatic parting method for calibrators based on feature recognitions is presented.Case-based reasoning theory was researched,the case library for calibrator,namely the standard feature library of calibrator 3D model and the process data library,based on feature is built,to design the calibrator mold-base,water channels,gas channels by case reasoning,and the design level of calibrator 3D modeling was improved.(3)The automatic dimensioning method of 3D model-to-engineering drawing was studied deeply.An automatic dimensioning method of calibrator based on the four-plate model was proposed.The calibrator plates were divided into four plate types,and drawing template was created,which simplified the process when newlybuilding engineering drawings.Based on feature extraction,the features of calibrators were recognized automatically and extracted,the redundant edges of engineering drawings were deleted automatically then,the engineering drawings were dimensioned automatically and laid out reasonably,further,thus the engineering drawings in line with the enterprise specifications were generated.(4)According to theory method of feature recognitions,the feature extraction,Case-Based Reasoning,by means of digital design,the calibrator CAD automatic modeling system was developed.and the case analysis and verification were carried out.The 3D digital design for calibrator was realized by the system.In this paper,the automatic modeling method of calibrator CAD is studied,That is,the automatic modeling from sketch drawing to 3D model,the automatic dimensioning from 3D model to engineering drawing,two aspects of the calibrator design were studied.The automatic modeling method of calibrator CAD is proposed,the three-dimensional design theory of calibrators were enriched.On the basis of theoretical research,the automatic modeling system of calibrator CAD was developed,and the system has been applied in enterprises,improving the design level and design efficiency,shorten the design cycle.