The methods to solve casting parts sticking molds trouble--(3)

1.3 The tightening force of casting parts against with mold


The casting part’s overall or partial shrinkage over-tighten the mold, or the size of the tightening force distribution is uneven/unreasonable, then the casting will occur deformation, cracks, breaks, and even casting part stick to the fixed mold, Or casting parts stick to the core side, and  can’t come out.


(1)   hthe overall or partial casting on the fixed clamping force is greater than the cavity of the tightening force, open mold when the casting will stay sticky die.


(2)   When releasing part, if the casting part’s tightening force against cavity and core is not uniform, will cause the casting part offset, the casting part area which has bigger strength against cavity will stick on the cavity side.


(3) If the mold temperature is too low, or the core side temperature is too high, will cause that the casting part tightening force against cavity is bigger than core when the casting part is shrinking.




 (4) mold release agent concentration is too low; release agent performance is not good;  release agent spraying on cavity is not in place or the amount of release agent is insufficient, which will affect the mold release. If the hot mold is sprayed with too much coating, the temperature of the mold is difficult to increase rapidly. After the cooling of the casting shrinks, the increase of the packing force on the fixed mold side will be larger than that of the core side.


(5) There is also a stick mold phenomenon: in the beginning of the die-casting production began a period of time, due to mold temperature is too low, die-casting alloy fluid flow decreased rapidly, resulting in metal liquid forming is not completed which filling in the cavity, so the forming casting part’s strength is very weak. The connection among the casting part is not solid, other part is easy to break which stick in the mold, especially in the condition while no ejecting mandrel in cavity side.  


For die-casting sticking mold problem, we should specific analysis its causes. For example: it happens that the casting part sticking in cavity side, it is necessary to check if the casting tightening force against cavity is too large; check the casting part surface of cavity side along with demoulding direction, sticking mold problem is happened in aluminum alloy die casting mostly, to solve the die-casting viscous defects in the specific measures are as follows.


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