Patent DE-102008039208-A1 (DE)
Title: Core for use in prototyping, especially for pressure casting or powder metallurgy, is obtained using metal sheath, molding material, mechanical shaping device and high pressure compression tube
IPC: B22C9/06
Filed: 2008-08-20
Abstract: A core (A) for use in prototyping is obtained using a metal sheath (similar to a storage container), molding material(s) (C), mechanical shaping device(s) (B) (e.g. a shaping wire or expanded metal body) for shaping the molding material (C) and internal high pressure compression tube(s). Production and use of a prototype core (A) involves: (1) producing a metal sheath, open in at least one region and optionally already containing mold grooves and pulling straps, using conventional shaping and joining methods; (2) inserting mechanical shaping device(s) (B) into the sheath; (3) inserting internal high pressure compression tube(s) into the sheath; (4) optionally sealing opening(s) in the sheath; (5) filling the sheath with solid molding material(s) (C); (6) sealing the filled sheath to give a gas-tight pre-core; (7) inserting the pre-core in a compression mold; (8) applying pressure to compress (C) using the tube; (9) optionally forming further mold grooves in the sheath; (10) treating the surface to cause binding or separation (as required) of prototyping material (D), thus forming (A), including a metal sheath (with a removal element and mold grooves), molding material, compression tube and molding auxiliaries; (11) inserting (A) into the core mark region of a prototype mold; (12) closing the mold and filling with (C); (13) hardening (C) in the mold (optionally after compression); (14) opening the mold and removing the molding, together with inserts, feeders and (A); (15) removing the inserts, feeders and any burs; (16) opening the sheath of (A) in the core mark region to release the end(s) of (B); (17) gripping or packing the released end(s) and separating (B) from the core region of the casting, while releasing the surrounding (C); (18) removing the tube and any remaining (c) to release the pulling straps; and (19) gripping or packing the strap(s) and separating the strap(s), together with at least part of the sheath, from the casting (specifically under sonication). One or more of stages 1-9 (especially stages 2-5) are optionally carried out in a different order or omitted. The prototype core (A) itself is also covered in the main claim. Independent claims are included for: (1) numerous variants of the above methods for production and/or use of prototype cores, and/or the obtained cores; (2) a core shaping and processing molding material (C'), suitable for use in the above process, consisting of mineral granules (especially sodium chloride, potassium chloride and/or magnesium sulfate), a gas-forming molding auxiliary (specifically a carbonate, especially calcium carbonate) and optionally (in)organic binder(s) (especially water or sodium or potassium waterglass), the novel feature being that the components are processed to give granules (specifically of size 0.1-0.3 mm) which do not separate during a mold core shaping procedure; (3) four variants of the molding material; (4) a mechanical shaping device for use in the process, having a shape (specifically consist of two crossed wire parts connected by a sheet metal clamp) having an internal supporting function for the core (A) during casting; and (5) two variants of the mechanical shaping device.