Calculation Methods of Planar Dimensional Chains and Spatial Dimensional Chains
At present,there are two prominent problems in dimension chain calculation:First,there is not a simple and easy-to-use general dimension chain calculation method which can calculate both linear dimension chain and plane dimension chain and spatial dimension chain.Secondly,when calculating the maximum and mini-mum dimensions in the existing literature,the average and tolerance of dimensions shall be calculated first,and then the average and deviation shall be combined to obtain the maximum and minimum dimensions.In this method,a se-ries of tolerance transfer coefficients have to be calculated in order to calculate the tolerance,and the calculation of the transfer coefficients is time-consuming due to the large amount of work.In view of the above problems,this pa-per provides a set of formulae which can calculate both the linear dimension chain and the plane dimension chain and the space dimension chain,including the formulae specially used to calculate the maximum and minimum di-mensions.With this formula,the maximum or minimum size can be calculated without calculating the average size,tolerance and transfer coefficient,thus saving calculation time and improving work efficiency.In order to explain the use of the formula,several representative technical problems encountered in the work are cited,involving process size calculation,coordinate size conversion and process equipment design.In terms of the types of dimensional chains involved,there are three types of dimensional chains such as 1D,2D and 3D.
dimension chain calculationplanar dimensional chainspatial dimension chainincrease ringde-crease ring
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