Patent DE-102007021679-A1 (DE)
Title: Method for expansion of flow with a movable cavity core, comprises latching the cavity core and producing a cavity with a first volume, injecting a first material into the cavity, and partially cooling and hardening the first material
Inventor: EHRLICHER STEFAN
IPC: C08J7/00
Filed: 2007-05-09
Abstract: The method for expansion of flow with a movable cavity core, comprises latching the cavity core and producing a cavity with a first volume, injecting a first material into the cavity, partially cooling and hardening the first material in the cavity, extending the cavity by removing the product of a cavity surface formed by the first material, sealing a supply for a second material opposite to the external environment thus developing space with a reception, so that a negative pressure develops without the supply of the second material, and filling the extended cavity with the second material. The method for expansion of flow with a movable cavity core, comprises latching the cavity core and producing a cavity with a first volume, injecting a first material into the cavity, partially cooling and hardening the first material in the cavity, extending the cavity by removing the product of a cavity surface formed by the first material, sealing a supply for a second material opposite to the external environment thus developing space with a reception, so that a negative pressure develops without the supply of the second material, filling the extended cavity with the second material parallel to the extension of the cavity by aspirating the material by the produced negative pressure, partially hardening the second material, and opening the cavity core and then receiving the formed products from the cavity core. A stamping step is simultaneously carried out with or after injecting the first material. The first cavity is narrowed in the stamping step. The filled material distributes itself in the entire cavity. The cavity core is displaced in the direction of the oppositely lying cavity wall for reducing the first cavity, and is subjected over a drive for displacement. The supply for the second material is already opened before the cavity is extended. An internal tool pressure drives against 0 bar after partial cooling and hardening, and is produced by displacing the cavity core in the direction of the oppositely lying cavity wall. The second material is made available under a pressure after opening the supply. The pressure of the second material supports the backpressure of the cavity core. The cavity core is actively withdrawn in speed-controlled manner. The extension of the cavity takes place up to an impact of the cavity core, is measured and is ended away from a certain degree. The extension is slightly held, so that a gap is formed with a capillary effect, which supports the flow process. The pressure for the second material, the degree of the extension and the execution of the extension of the cavity are coordinated on each other and on the used second material, so that a fast and an even flow of the product formed in the first step are reached. The supply of the material is ended or latched and the internal tool pressure is increased after the extension of the cavity and flow of the product formed in first step. A hold pressure is produced after filling the extended cavity with the second material. The internal tool pressure of 9 bars is driven and the locking force is reduced before opening the cavity core. The cavity core is continuously held under locking pressure in a time period between the latching and opening step. The product is held by negative pressure on the cavity surface during the extension of the cavity. An independent claim is included for a device for the expansion of flow with a movable cavity core.