Non-destructive on-line monitoring of nylon cast process

Nylon Casting is a thermo-chemical process carried approximately at 150° C. The process involves charging the reaction vessel with molten monomer and subsequent polymerisation associated with an exotherm taking final product temperature to 200° C. During this process phase change occurs, by studying the heat of exotherm and corresponding reaction time provides valuable information about casting process. If the reaction is too slow, resultant polymer has low molecular mass and high oligomer content. If the reaction is too fast the resultant polymer is prone to stress cracking, voids and of low molecular mass. Hence there is a tight production window into which production must fall. A technique for rapid, efficient and non-destructive online monitoring system for casting process was lacking. Various authors had monitored the reaction and studied reaction kinetics. But no readily monitoring system was available. The present technique represents a novel interpretation method based on gradient changes (differentiation). This interpretation is 'real-time post-calculated' based on buffer data management system. Calculations are activated by an upper trigger switch and calculation is back regressed on 'nearest-minima' basis. the calculated date is time stamped and saved to a secondary file. Calculated data is 'reaction rate' (dT / dt) and reaction end point (T65- nominal solidification point) are displayed on the screen. By using this tool blue print of the reaction can be obtained. This also includes pour temperature, tool temperature, oven temperature and reactions time that are essential for reaction optimization and defect reduction.