| 摘要 |
Plasticizable material is pressure molded into articles free from flash in mold cavities of specialized molds defined by separate mold sections with removable cores. Prior to and during molding, the sections are held clamped together to fully confine the material which is pressurized by reducing the volumetric capacity of each cavity. This pressurization is maintained until the material is set or cured, and may be increased before final set to forge or densify the material further. The method employs a conventional press and two gangs of specialized two-piece, multi-cavity molds. The molds of each gang are supported in a horizontal row, with their juxtaposed flat faces and parting planes disposed vertically, for movement of each mold section flatwise endwise of the row to open and closed positions. The mold sections are clamped closed by power means which apply extraneous clamping pressure independently of the press operation. The gangs are supported so that as one clamped gang is moved into molding position in the press the other clamped gang is moved out of the molding position to an unloading and recharged position wherein it is unloaded and recharged while molding is being effected by the gang in molding position. Each mold cavity has an entry passage which opens through the upper edge of its associated mold sections. In the charge position, predetermined charges of the material are introduced into the cavities, respectively, through the entry passages. The clamped gang is moved as a unit into the operating or mold space of the press. Therein, plungers, carried by the press platen and driven by the closing force of the press, enter the entry passages and move therealong so as to progressively reduce the volumetric capacities of the cavities concurrently and thereby pressurize and forge the material therein to the degree desired. The extraneous clamping pressure is sufficient pressure to prevent any escape of material from the cavities at the parting surfaces of the mold sections.
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