BLUE MATCHING & WEDGE MATCHING OF CORE & CAVITY

 

BLUE MATCHING & WEDGE MATCHING OF CORE & CAVITY

 

Blue matching was the final stage of assembly work. It is the process in which both the core and cavity parting surface are matched exactly to avoid plastic flow during moulding (flash free). In this process a thin film of blue was applied on any one side, either core or cavity parting lines. The tool was closed; a slight force was applied and was opened. The high spots where blue is picked up was removed either by diamond file, oilstone or by pneumatic grinders, if it was irregular parting line; otherwise the parting line levels were surface ground. This process is done till blue matches on both halves evenly.

 

            Wedge matching is a process in which wedges are ground and matched to the side cores ensuring efficient locking of side cores with the matching face and at the same time correct matching at the parting surface.

 

            The core and the cavity halves are assembled. The ball catch was fixed in the wear plates and guide rails by screws in order to position the sides’ cores. Finally side cores are were assembled.

               

Blue is applied on the parting surfaces. The two halves are then closed. There will be some gap between the parting surfaces, as there will be some stock on the angled surface of wedges for wedge matching. Depending upon the gap between both halves, which is checked using feelers gauge or lead the stock material, is ground so as to achieve the matching of the core and cavity.

 

The method of calculating the gap between the two halves is as follows;

      

         Calculation is done for the amount of material to be removed in wedge using formula

                                     A=SIN XB

      Where,                   A=material to be removed,

                                       =Wedge angle,

                                    B=gap between parting surfaces.