Method and apparatus for the production of moulds for full mould casting

摘要

In the full mould process, patterns composed of materials which vaporise when the mould is filled are embedded in a free-flowing moulding material and the latter is compacted by means of vibrations. In order to allow the shape of undercut patterns or those with cavities closed at the top to be taken satisfactorily, the moulding material is excited with a vibration at an angle alpha < 90@ relative to the horizontal plane on one side of the patterns and with a vibration at an angle beta = 180@ - alpha relative to the horizontal plane on the opposite side of the pattern and, as a result, the moulding material executes a spiral movement upwards and fills undercuts and cavities from below. An apparatus for carrying out the method consists of a table which supports the patterns and a moulding container surrounding the latter and of two vibration generators mounted on the table symmetrically to its centre, each of which is mounted on the table at an angle to the horizontal plane such that the direction of vibration of one generator is at an angle alpha < 90@ and that of the other is at an angle beta = 180@ - alpha .