Method for producing an ordered array of interconnected acoustic microchannels
A manufacturing method of an acoustic coating in an ordered array of interconnected micro-channels intended to receive, on a reception surface, an incident acoustic wave with direction Ac normal to this surface, the method including depositing a sacrificial material on a substrate surface to form a three-dimensional scaffold of filaments, infiltrating at least one part of the three-dimensional scaffold with a thermosetting material, solidifying the thermosetting material to form a solidified material, and removing the sacrificial material from the solidified material to form the ordered array of interconnected micro-channels, the filaments forming by superimposed layers the three-dimensional scaffold being, for a given layer of filaments, oriented in a direction forming, in a plane formed by the layer, a first angle θ relative to the direction Ac of the incident acoustic wave, to confer acoustic properties to the ordered array of interconnected micro-channels and thus form the acoustic coating.
1. A manufacturing method of an acoustic coating in an ordered array of interconnected micro-channels intended to receive, on a reception surface, an incident acoustic wave with a direction normal to the reception surface, the method comprising:
depositing a sacrificial material on a substrate surface to form a three-dimensional scaffold of filaments,
infiltrating at least one part of said three-dimensional scaffold with a thermosetting material,
solidifying said thermosetting material to form a solidified material, and
removing said sacrificial material from said solidified material to form said ordered array of interconnected micro-channels,
wherein, to confer acoustic properties to said ordered array of interconnected micro-channels and form said acoustic coating, said filaments forming by superimposed layers said three-dimensional scaffold are, for a given layer of filaments, oriented in a direction forming, in a plane formed by said layer, a first predetermined angle relative to the direction of said incident acoustic wave, and
wherein a diameter or a cross-section width of the filaments is less than 250 microns.
2. The manufacturing method according to claim 1 , wherein said filaments have a different diameter or cross-section width depending on the orientation direction of said filaments in said three-dimensional scaffold.
3. The manufacturing method according to claim 1 , wherein said superimposed layers forming said three-dimensional scaffold include filaments oriented, for some, according to the first predetermined angle and, for others, according to a second angle being a negative value of the first predetermined angle, a layer of filaments oriented according to the first predetermined angle following a layer of filaments oriented according to said second angle.
4. The manufacturing method according to claim 1 , wherein said first predetermined angle is comprised between 25° and 40.
5. The manufacturing method according to claim 1 , wherein the fill rate of said three-dimensional scaffold is at least 70%.
6. The manufacturing method according to claim 1 , wherein said sacrificial material is an organic ink or a natural wax.
7. The manufacturing method according to claim 1 , wherein said thermosetting material is a polymer resin.
8. The manufacturing method according to claim 7 , wherein said polymer resin is a photo-polymerizing resin.