In an example, a method includes identifying, by processing circuitry, a feature of less than a threshold size of an object to be generated in additive manufacturing. In some examples the method further includes determining, by processing circuitry, a first density of a print agent to be applied to build material when generating the identified feature of the object based on an intended flexibility of the feature of the object. The method may further include determining, by processing circuitry, a second density of print agent to be applied to build material when generating another feature of the object.

Applicator for cosmetic product having an elongate general shape in a longitudinal direction, including a fixed part and a part movable in relation thereto. The movable part includes protrusions, at least one chain having a strand forming a succession of open loops, the chain extending substantially parallel to the longitudinal axis of the applicator. The fixed part includes at least two links, at least two of the open loops on each chain being passed through by a link of the fixed part. Thus, each chain of the movable part is fastened with at least one degree of freedom to the fixed part, enabling relative movement of the chain in relation to the fixed part longitudinally. This improves quality of the application of the product and gives the applicator a sensation of flexibility, even if the applicator is constituted by a rigid material. The applicator can be made by additive manufacturing.

A method for manufacturing a cylindrical brush of a cleaning tool, comprises a cylindrical brush having a core member, a plurality of rail plates, a plurality of polyvinyl alcohol (PVA) nodule foam bars and a pair of end caps. The core member includes an outer wall having a plurality of core holes and a pair of openings. The plurality of rail plates having a plurality of rail holes arranged along the outer wall of the core member. The plurality of polyvinyl alcohol (PVA) nodule foam bars is installed at each of the plurality of rail plates such that each of a plurality of nodules of the PVA nodule foam bar aligns with the plurality of core holes and with the plurality of rail holes. The pair of end caps encloses the pair of openings of the core member.

Provided is a method of manufacturing a brush, such as a wafer cleaning brush. The method includes providing a polyvinyl alcohol (PVA) solution, forming an insoluble polyvinyl fluoride (PVF) by adding formaldehyde to the PVA solution, adding a water-soluble inorganic compound including a plurality of particles to the insoluble PVF, and mixing the insoluble PVF with the water-soluble inorganic compound to form a mixture of the water-soluble inorganic compound and the insoluble PVF, forming a brush by inserting the mixture of the water-soluble inorganic compound and the insoluble PVF into a mold and heat-treating the mixture, removing the wafer cleaning brush from the mold; and washing the wafer cleaning brush to remove the plurality of particles of the water-soluble inorganic compound from the wafer cleaning brush.