STUDDING EFFECT OF DESIGN TOLERANCES UPON PROCESS CAPABILITY

	STUDDING EFFECT OF DESIGN TOLERANCES UPON PROCESS CAPABILITY
AL-TAQANI
Article 1, Volume 24, Issue 2, 2011, Pages 0-0
Abstract
In Babylon factory, the percentage of defective units in production of medical syringes very high that is very high because the dimensions of products are not conforming for specified specifications and increasing demand on products. Thus, manager of the factory asked analyses of process of production to determinate percentage of scrap and rework because of the external diameter of the gasket piston is less than lower specification limit and reworks due to the external diameter greater than upper specification limit, and the cost of it due to scrap or rework are high and causing confusion at next assembly operations where the cost of scrap is equal to cost of rework. The research aims to study the external diameter of the gasket piston because of an increasing diameter of gasket from specification which results an increasing in applied pressure on hup cylinder which results difficult in moving of piston while decreasing the diameter from specification does not seal of preventive process flow of liquid causes of entering air and easy of piston motion. The search dealt calculating of control limits for and found that process in control and follows normal curve. Thus, the process capability is calculating and percentage determinating of rework and scrap and studding to modify the mean and variability of process an selecting the best solution. An effects appear the solution for modifying the variability of process from(0.03) to (0.02) is the best solution because that solution will reduce the percentage of defective production from to and the percentage of rework will reduce to zero without that is effecting upon mean of process.
Keywords
design tolerances; variability of process; mean of process

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