Methods, particularly automated methods, are provided, as well as 3D-printed composite and hollow objects and 3D-printing systems for printing them. Methods comprise deriving a central line of a hollow 3D object model, calculating reference point(s) and/or line(s) along an inner surface of the hollow 3D object model, and filling the hollow 3D object model with material that comprises a thread defined with respect to the central line and the reference point(s) and/or line(s) and with filling material surrounding the thread. The support construction thus formed may be removed from the 3D object by pulling on the thread, extracting it and the surrounding support filling from the hollow object, thus enabling 3D-printing of convoluted or elongated hollow objects and objects with narrow openings. The parameters of the thread, such as type of curve and thickness, are selected to ensure thread extraction without risk of tearing or knotting the thread.

A method and apparatus for the formation of double-walled containers with the structure of two integrally connected and adjacent containers extending in the same direction with an air gap between them, stretch-blow moulded as single bodies out of thermoplastic material, and suitable for mass-production. A thermoplastic tubular blank is formed and then heat-conditioned. The heat-conditioned tubular blank is then mechanically stretched longitudinally and blow-formed outwards by gas pressure to conformingly and stretchingly assume the tubular blank to the shape of a first dual-container shaped mould cavity set in order to form a stretch-blow moulded first container integrally connected to a second container, with both containers extending in opposite directions. Next, additional heat-conditioning is applied to further heat-condition as necessary the stretch-blow moulded second container and if deemed an advantage, at least part of the first container. Then at least one profiled inversion piston and a second dual-container shaped mould cavity set are provided along with one or more wall stability devices applied to at least part of the wall surface(s) of either or both of the two integrally connected stretch-blow moulded containers, such that the second container side wall(s) may be inverted at least partially inside-out, while at the same time the second container bottom wall at least substantially does not invert, in order for the second container to become a substantially mirror-image inverted second container extending in the same direction as the first container, and an air gap is formed between the first container and second container.

A method and apparatus for the formation of double-walled containers with the structure of two integrally connected and adjacent containers extending in the same direction with an air gap between them, stretch-blow moulded as single bodies out of thermoplastic material, and suitable for mass-production. A thermoplastic tubular blank is formed and then heat-conditioned. The heat-conditioned tubular blank is then mechanically stretched longitudinally and blow-formed outwards by gas pressure to conformingly and stretchingly assume the tubular blank to the shape of a first dual-container shaped mould cavity set in order to form a stretch-blow moulded first container integrally connected to a second container, with both containers extending in opposite directions. Next, additional heat-conditioning is applied to further heat-condition as necessary the stretch-blow moulded second container and if deemed an advantage, at least part of the first container. Then at least one profiled inversion piston and a second dual-container shaped mould cavity set are provided along with one or more wall stability devices applied to at least part of the wall surface(s) of either or both of the two integrally connected stretch-blow moulded containers, such that the second container side wall(s) may be inverted at least partially inside-out, while at the same time the second container bottom wall at least substantially does not invert, in order for the second container to become a substantially mirror-image inverted second container extending in the same direction as the first container, and an air gap is formed between the first container and second container.

A latex composition includes a conjugated diene polymer latex and a silicone-based surfactant having a silicon atom content of 1.5 to 10 wt %. A dip-molded article is formed by dip molding the latex composition.

A blow-molded unitary structure includes a panel having upper and lower panel surfaces and a ridge extending downward beyond the lower panel surface. The ridge includes a first side surface, a second side surface, and a lower ridge surface joined with the first side and second side surfaces of the ridge. The ridge further includes a plurality of depressions formed at one or more of the first side surface, second side surface and lower ridge surface. The plurality of depressions enhances the strength of the ridge, and the ridge in turn enhances the strength of the structure.

A blow-molded unitary structure includes a panel having first and second panel walls and a generally hollow interior between the first and second panel walls. The structure also includes a plurality of depressions, or at least one ridge, or both the depressions and ridge to enhance the strength of the structure. The plurality of depressions is monolithically formed with the panel, recessing from the second panel wall toward the first panel wall. A depression has a side wall composed of first and second segments. Cross-sectional-wise, the first and second segments have different widths and thus collectively forms a step between the first and second segments. A ridge is also monolithically formed with the panel and includes a section, at which the width of the ridge varies along the height direction of the ridge.

A mechanical assembly for securing a first sheet to a second sheet includes a first projection having a first sidewall and a first top wall. The first sidewall extends from the first top wall at a first acute angle. The first sidewall includes a first top end and a first bottom end. A first discontinuity is defined in the first sidewall between the first top end and the first bottom end. A first base wall extends from the first bottom end. The first base wall extends generally parallel to the first top wall.

A method for manufacturing a double-wall container includes a blow molding process of forming an intermediate molded body by blow molding, the intermediate molded body including a projection part that is provided at a boundary portion between an inner wall forming part and an outer wall forming part and projects outward in a radial direction of the outer wall forming part; an inverting process of pushing the inner wall forming part inside the outer wall forming part and inverting the inner wall forming part, thereby forming the intermediate molded body into the double-wall container; and a collapsing process of collapsing the projection part in a depth direction of the intermediate molded body to form a crease at the boundary portion between the inner wall forming part and the outer wall forming part, the collapsing process being performed before the inverting process.

Methods, particularly automated methods, are provided, as well as 3D-printed composite and hollow objects and 3D-printing systems for printing them. Methods comprise deriving a central line of a hollow 3D object model, calculating reference point(s) and/or line(s) along an inner surface of the hollow 3D object model, and filling the hollow 3D object model with material that comprises a thread defined with respect to the central line and the reference point(s) and/or line(s) and with filling material surrounding the thread. The support construction thus formed may be removed from the 3D object by pulling on the thread, extracting it and the surrounding support filling from the hollow object, thus enabling 3D-printing of convoluted or elongated hollow objects and objects with narrow openings. The parameters of the thread, such as type of curve and thickness, are selected to ensure thread extraction without risk of tearing or knotting the thread.

An aircraft flap is constructed of nested layers of composite material in the aircraft flap that include an inner layer, a middle layer and an outer layer. The aircraft flap is constructed with the inner layer laid up around a central mandrel, the middle layer laid up around the middle layer and the outer layer laid up around the middle layer. The inner layer, the middle layer and the outer layer are co-cured on the mandrel, removed from the mandrel and then assembled together with the inner layer formed in a folded over configuration around a hollow interior volume of the aircraft flap, the middle layer formed in a folded over configuration over the inner layer, and the outer layer formed in a folded over configuration around the middle layer.