The invention concerns a process for the production of a mold core for the one-part production of wind power installation rotor blades. According to the invention the method includes the steps: providing a flexible hollow body, for example a film tube, inserting the hollow body between at least two mold portions which are so arranged relative to each other that they form a negative shape of the rotor blade to be produced, filling the hollow body with loose material prior to or after insertion of the hollow body between the mold portions, and producing a reduced pressure in the hollow body after it has been filled and inserted in such a way that the hollow body solidifies. The invention further concerns a process for producing a reduced pressure between mold portions and mold core.

An impression device and related methods are disclosed. The device has a base having a recess and a conduit for fluidly coupling the recess to a vacuum source, and a first plurality of particles positioned in the recess. The first plurality of particles sealed from an external environment. The first plurality of particles has a first coefficient of friction between each other, the first coefficient of friction selected to allow the particles to move relative to each other in the absence of a vacuum and to prevent the particles from moving relative to each other in the presence of a vacuum.

A material system including a plurality of expandable pellets or a monolithic flexible carrier is disclosed, each of which may include a polymer matrix configured to hold an expandable core, and a flexible skin configured to encapsulate the polymer matrix, and where the flexible skin is at least partially permeable with respect to the expandable core or a gas released by the expandable core. Implementations of the material system may include where the polymer matrix may include a thermoplastic polymer. The material system may include a charging source configured to introduce blowing agent. A method of curing a composite part is also described.

A tooling element includes a flexible sleeve defining an interior cavity. The flexible sleeve includes a sealable access port extending through the flexible sleeve from the interior cavity to an exterior of the flexible sleeve. The tooling element further includes vacuum-packed tooling particulate disposed within and filling the interior cavity of the flexible sleeve.

A method for producing a hologram on a curved substrate plate includes providing a curved substrate plate having a substrate surface, the actual geometry of which is subject to a tolerance deviation with respect to a predetermined desired geometry; providing an inflatable cushion with a cushion surface that can be deformed under the effect of pressure and is preformed into the predetermined desired geometry or with a predetermined deviation therefrom; applying a holographic master in the form of a flexible thin layer to the deformable cushion surface and applying a hologram-recording layer to the substrate surface; pressing or placing the holographic master onto the hologram-recording layer by way of the cushion surface deformed to the actual geometry, thereby achieving full surface-area contact between them with a substantially constant predetermined layer thickness of the hologram-recording layer, and exposing the hologram-recording layer to form a hologram.