Development Of Fixture Design Case Retrieval And Navigation System On Platform SV

The design cycle and production period are being shortened under the driving factors of varied market demand and rapid renewal of products. Generally, the traditional methods of devising a fixture scheme are hard to meet the practical production requirement in that the fixture design is usually a tedious, time-consuming and low-efficiency process. With the rapid growth of manufacturing informationization, the development of computer-aided fixture design (CAFD) system is drawing more attention. Focusing on the long design cycle and low efficiency problems in the fixture design process, a computer-aided fixture design system was designed and implemented on the platform SINOVATION (SV), with the aim to assist the fixture designers to complete their work quickly and accurately.Based on the analysis of current computer-aided fixture design systems implemented with CBR, and on the examination of fixture case database and fixture components database on the platform SV, the fixture case retrieval system was proposed; the expression mechanism and encoding rules for feature items and characteristic properties of work-piece were established; and the fixture cases were expressed by using work-piece feature item and feature attribute. The processing content and structural characteristics of work-piece were extracted and applied to the similarity values calculation by the way of feature items. The greater similarity value of fixture case will be reused directly or slightly modified to improve the design efficiency and accuracy. The reused fixture case will be saved into database in the form of expressing mechanism and encoding rules of the predefined feature item and feature attribute so that they can be used in the next retrieval. Considering the model compatibility with other3D modeling software, an interface program based on STEP203was designed and developed, so that the work-piece structure information can be extracted and the processing contents of work-piece can be recognized, then the retrieval of fixture cases can be finished.After summarizing the merits and demerits of current RBR with computer-aided fixture design, a fixture design navigation system based on rule reasoning was designed. With the comprehensive consideration of the previous experience of fixture design and the advice of experts, the method of building case database and rules database for positioning and clamping design were studied, and the positioning and clamping system was developed. The positioning and clamping scheme can be quickly designed which is suitable for this work-piece and the positioning and clamping elements were selected through the system, and finished the fixture design in the assembly environment on SV; Taking into account the impact of the clamping force on the clamping scheme, a clamping force estimation module was designed. According to the processing conditions and cutting parameters of work-piece, the required cutting force was calculated, and on this basis the clamping force which required also was calculated based on clamping condition in order to avoid the failure with fixture design because of improper use of clamping force. Besides, a clamping layout optimization module was designed. In order to gain the optimal clamping layout for new problems, PSO optimization algorithm was employed for the clamping layout optimization of the tooling plan produced by the design navigation system with the use of finite element method.The system was developed and configured on the platform SV. System development design framework and operation process were conducted, the Fixture Design Case Retrieval and Navigation System based on SV was developed. The running relationships between various modules were analyzed. The generation process of system program and the registration method of the menu bar were introduced. Finally, the operation process and the system of software implementation were presented.