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| The Shifts. |
The
shift are miss matching of the different parts of a mould at the joint lines and
shifts may be caused by the use of under size moulding box prints or by movement of the face of the moulding during rolling over.
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| The Fins |
The
fins are flash alone the joints lines of castings may be used when the moulder raps the pattern excessively before the with drawn's it from the mould. If the moulder does not place sufficient weight on the top part of the mould or fails to see that the parts of the mould are tightly clamped the top part of the mould
fins may lift slightly.
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| The Bellow holes. |
The
bellow holes are smooth rounded holes visible on the surface of a casting may be one large smooth depression. They are caused by high moisture low permeability. Expensive fine grains and gas producing ingredients by extra hard ramming and improper venting by the moulder any one of these variations from the correct practice may cause
bellow holes and it is some times difficult to determine exactly which is responsible.
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| Shrinkage cracks. |
The
shrinkage cracks with oxidized walls and following a jagged path.If the metal is pulled apart in the mould while in plastic conditions but the design and feeding have been checked and found sat is factory
shrinkage cracks and cavities may be caused too low pouring temperature.
