Research On The Theory And Method Of Virtual Assembly

Facing violent market competition, how to push the new product into the market with the fastest speed and occupy the market rapidly is the key to the survival of the enterprises, for this reason, the scholars over the world have put forward many new product developing strategies, produce modes and advanced manufacture technologies. But these strategies, modes and technologies can not dispense the process radically that the prototyping has to be manufactured again and again during product development. The main reason of this is that the problems about assembly and maintenance in product design can only be exposed during manufacturing or after sold, therefore the virtual reality technology was applied to product assembly design and the virtual assembly was emerged. Since the virtual assembly technology can merge the assembly engineer's knowledge and experience into product assembly design, that the assembly engineer can make reasonable evaluation to the product assemblability and disassemblability at the early stage in product design, and the virtual assembly technology was welcomed deeply by the enterprises. Although the virtual assembly technology has been applied in motor and airplane enterprises and preliminary achieves have been made, but the theories and techniques about the virtual assembly technology are all immature .So this thesis will analyze and study the relevant theories and techniques of the virtual assembly technology deeply.Firstly , Be based on the theory of Virtual Assembly and its application technology, this thesis makes further analysis and study on theory of Virtual Assembly and its key technology— Assembly Modeling has developed by all means degree. A new hierarchy structural relative of the virtual assembly technology was advanced and Assembly tool model was preliminary study.Secondly, Virtual Process Planning and evaluation were researched and as far as the assembly process planning is concerned, disassembly technique were mostly analysis and study, and samples is also given to prove it.Lastly, the method for tolerance and fit checking up and analysis is concerned. Reference date-base is established on the basis of standard tolerance and preference fit by state criterions. The rules for tolerance and fit checking up are proposed, tolerance and fit are checked up by searching the date-base by Visual Basic and the tolerance which fall short of design are found out and then advice of modification are proposed. Afterwards, tolerance chain is analyzed by using the worst situation analytical methodand statistic analytical method which are opted based on practical situation of production. The percentage contribution analytical method for tolerance chain which fall short of design is carried out and modification advice for the tolerance which has a larger percentage contribution is proposed. Gear-shafting parts is given to prove it.