A preform assembly includes: an outer preform that includes an outer mouth portion and a stretch portion connected to the outer mouth portion and in which a recess extending in a vertical direction is provided on an inner surface of the stretch portion; and an inner preform that includes an inner mouth portion and a stretch portion connected to the inner mouth portion, wherein an outside air introduction port communicating with a part between the outer preform and the inner preform is provided in a mouth portion composed of the outer mouth portion and the inner mouth portion located on an inner side of the outer mouth portion.

A preform assembly includes: an outer preform that includes an outer mouth portion and a stretch portion connected to the outer mouth portion and in which a recess extending in a vertical direction is provided on an inner surface of the stretch portion; and an inner preform that includes an inner mouth portion and a stretch portion connected to the inner mouth portion, wherein an outside air introduction port communicating with a part between the outer preform and the inner preform is provided in a mouth portion composed of the outer mouth portion and the inner mouth portion located on an inner side of the outer mouth portion.

A preform can be made from two different materials that do not bond together by a bi-injection process, using the same mold. First an outer preform can be fashioned, then an inner preform molded through a center hole in the bottom of the outer preform, and the preforms connected. Inner/outer preform materials can be different, e.g., PET/polyolefin or polyamide, or same, e.g., PET/PET. To prevent mutual bonding during molding of the second, a non-stick coating can be sprayed on a surface portion of the first preform prior to molding the second. Manufacturing order can be either outer/inner, or inner/outer, and the non-stick coating sprayed on the inside/outside of the preform first molded.

The present invention provides a blocking piece covering the sound hole of a loudspeaker and an assembling method thereof, and a loudspeaker module. The blocking piece covering the sound hole of the loudspeaker module is arranged at a position where the sound hole is located on the case of the loudspeaker module and covers the sound hole. The blocking piece is made of a nonmetallic flexible net. The nonmetallic net-shaped blocking piece and the case are formed integrally by injection moulding. The loudspeaker module and the blocking piece covering the sound hole thereof in the present invention have advantages of good acoustic performance, high reliability, high space utilization rate and high production efficiency. The assembling method for the blocking piece covering the sound hole of the loudspeaker module further makes the assembling of the blocking piece convenient for operation, and improves the assembling efficiency and assembling quality.

The present invention provides a blocking piece covering the sound hole of a loudspeaker and an assembling method thereof, and a loudspeaker module. The blocking piece covering the sound hole of the loudspeaker module is arranged at a position where the sound hole is located on the case of the loudspeaker module and covers the sound hole. The blocking piece is made of a nonmetallic flexible net. The nonmetallic net-shaped blocking piece and the case are formed integrally by injection moulding. The loudspeaker module and the blocking piece covering the sound hole thereof in the present invention have advantages of good acoustic performance, high reliability, high space utilization rate and high production efficiency. The assembling method for the blocking piece covering the sound hole of the loudspeaker module further makes the assembling of the blocking piece convenient for operation, and improves the assembling efficiency and assembling quality.

Methods and apparatus for additive manufactures of complex parts using co-aligned continuous fibers are disclosed. Filament subunits having complex shapes are fabricated and inserted into a mold cavity. The layup is compression molded to form a complex part having high tensile strength.

Disclosed are an embedded co-cured composite material with large-damping and electromagnetic wave absorbing properties and a preparation method and an application thereof, belonging to damping composite materials. The embedded co-cured composite material is formed by interlacing a plurality of electromagnetic wave absorbing prepreg layers and a plurality of electromagnetic wave absorbing damping layers. Each of the electromagnetic wave absorbing prepregs layers includes a fiber cloth, a micro-nano electromagnetic wave absorbing material and a resin. Contents of the micro-nano electromagnetic wave absorbing material in the electromagnetic wave absorbing prepreg layers and the electromagnetic wave absorbing damping layers have a gradient increase or decrease according to a sequence of the electromagnetic wave absorbing prepreg layers. Each of the electromagnetic wave absorbing damping layers includes a viscoelastic damping material and the micro-nano electromagnetic wave absorbing material.

Disclosed are an embedded co-cured composite material with large-damping and electromagnetic wave absorbing properties and a preparation method and an application thereof, belonging to damping composite materials. The embedded co-cured composite material is formed by interlacing a plurality of electromagnetic wave absorbing prepreg layers and a plurality of electromagnetic wave absorbing damping layers. Each of the electromagnetic wave absorbing prepregs layers includes a fiber cloth, a micro-nano electromagnetic wave absorbing material and a resin. Contents of the micro-nano electromagnetic wave absorbing material in the electromagnetic wave absorbing prepreg layers and the electromagnetic wave absorbing damping layers have a gradient increase or decrease according to a sequence of the electromagnetic wave absorbing prepreg layers. Each of the electromagnetic wave absorbing damping layers includes a viscoelastic damping material and the micro-nano electromagnetic wave absorbing material.

Methods and apparatus for additive manufactures of complex parts using co-aligned continuous fibers are disclosed. Filament subunits having complex shapes are fabricated and inserted into a mold cavity. The layup is compression molded to form a complex part having high tensile strength.

Container comprising an inner container and an outer container with facing surfaces, wherein at least part of at least one of the facing surfaces has a surface roughness higher than about 0.1 Ra and/or wherein the difference in roughness of said facing surfaces is at least over a part more than about 0.1 Ra.