| 摘要 |
A method of fabricating an inner core tool for use in lost core moulding process characterized by the steps of: providing a rigid mould (12, 13) which reproduces on a working surface (12A, 13A) of the mould the final external form of the inner core tool; introducing a flexible mould bag (17) into the rigid mould; providing a filling duct passage (19) to the interior (18) of the mould bag from outside the mould; causing the mould bag to be drawn into contact with the working surface (12A, 13A) of the mould; filling the interior (18) of the mould bag at least in part with particles by way of the filling duct so as to provide for close packing of the particles within the mould bag so as to cause the bag at least in part, to conform closely to the working surface; closing the mould bag (17) gas tightly so as to isolate the interior of the bag (18) from ambient air pressure except for an evacuating duct; evacuating air from the interior of the bag by way of the evacuating duct to cause the mould bag and its mass (M) of close packed particles to rigidify and thereafter closing the duct air tightly to maintain a sub-atmospheric pressure within the mould bag; removing the rigidified mould bag from the rigid mould. Preferably the method is further characterized by the incorporation within the mould bag of an expanding device so that in use as an inner core tool the rigidified mould bag can be subjected to internal pressurisation by way of the expansion device so as to urge the mould bag outwardly into contact with material juxtaposed with the mould bag. Further aspects of the invention comprise an inner core tool produced by the method, a moulding method involving the use of a core tool and a mould component produced by the moulding method. |
