TOLERANCE CONTROL FOR DIMENSIONAL AND GEOMETRICAL SPECIFICATIONS

The development of tolerance charts has come a long way from the past manual methods to the current computer-aided models. As a result, many techniques have emerged over, the years. However, the area of geometr ical tolerance charting has nor been given much attention. In view of this, this paper addresses both linear and geometrical tolerance contr ol. The method proposed in this paper allows the user to construct a m odel directly from the process plan. The relevant process links betwee n any two planes which are required to satisfy both the linear and geo metrical requirements are easily obtained from the model. Having estab lished all the appropriate constraints, the linear programming optimis ation software is used for the determination of the unknown working di mensions and tolerances. In essence, this paper presents a new methodo logy for deriving the process links from the process plan and also hig hlights the significance of the use of linear programming in achieving the optimal tolerance mix or combination.