Patent EP-1872928-A1 (EP)
Inventor: EDERER INGO
IPC: B29C67/00
Filed: 2007-06-26
Abstract: The building of a multilayer structure (1) from a number of superimposed layers made up of particulate material, comprises individually applying each of the layers at a predetermined layer thickness one above the other by delivery of the particulate material from a coating device during its movement above the base structure, selectively localizing and solidifying in the areas of the layers that are specified in accordance with the computer data and a metering device (2), and building the multilayer composite freely-lying on the base structure without the use of an external delimiting device. The building of a multilayer structure (1) from a number of superimposed layers made up of particulate material, comprises individually applying each of the layers at a predetermined layer thickness one above the other by delivery of the particulate material from a coating device during its movement above the base structure, selectively localizing and solidifying in the areas of the layers that are specified in accordance with the computer data and a metering device (2), and building the multilayer composite freely-lying on the base structure without the use of an external delimiting device for the respective uppermost layer to be applied by operating the metering device on a framework (5), which is vertically adjustable step by step and is adjusted vertically upwards before the application of the respective uppermost layer by a value corresponding to its layer thickness. The metering device is used as the coating device, which has a downwardly opened and longitudinally stretched delivery gap for the particulate material, which extends rectilinearly horizontal and perpendicular to the direction of motion of the metering device and is turned on and off during its motion for the controlled delivery of the particulate material. The superimposed layers lie on a base structure, solidified in localized areas and bonded with one another so that a structured body is formed from the solidified areas of the layers. The metering device is set in motion from a position, in which its delivery gap is present in the direction of movement of the metering device at a distance in front of the frontal edge of the next bottom-lying layer. The metering device is moved beyond the edge of the next bottom-lying layer that lies behind with respect to the direction of motion and then switched off if its delivery gap is present in the area above the rear edge of the next bottom-lying layer. The uppermost layer is smoothened and/or compacted during the movement of the metering device along the direction of movement behind the delivery gap. The compaction is carried out in a motion component along a direction of compaction that coincides with the direction of motion of the metering device. A metering device is used that has a delivery channel, which contains the particulate material to be applied, leads at its lower end into the delivery gap and is switched on. The particulate material vibrates in the delivery channel and is fluidized. The layers are applied at a thickness of 100-500 mu m at a grain size of the particles of the material from 50-200 mu m. The applied uppermost layer is solidified along the edge region of its edge that lies in the front with respect to its direction of motion of the metering device by exposure to a radiation or by applying a binder, so that a solidified limitation of the layers of the multilayer structure is built of particulate material along its side that lies in the front with respect to the direction of motion of the metering device. The edge region of the uppermost layer is solidified extending from the frontal edge facing the solidified edge region of the next bottom-lying layer to the vertical center of the multilayer structure, so that the limitation wall runs at an angle to the perpendicular. The metering device is switched off, if its delivery gap is present closely above the edge region of the next bottom-lying layer that lies behind with respect to the direction of movement of the metering device. The metering device is switched on during its movement, if its delivery gap is present at a distance closely behind the edge of the next bottom-lying layer along the direction of movement. The lifting drive mechanism for raising the metering device and the operation drive mechanism of the metering device are controlled depending on one another. An independent claim is included for a device for building a multilayer structure from a number of superimposed layers made up of particulate material.