Metal plated additively manufactured plastic ACM rotors with internal thermally adaptive structure

1 . A method of forming a rotor for an air cycle machine (ACM), the method comprising:

forming a rotor base having a plurality of discrete sections including: a first section that is adjacent to a diffuser shroud when installed in the ACM; a second section that forms a seal and is disposed against an aft frame member when installed in the ACM; a third section that is connected to a compressor rotor shaft when installed in the ACM; a fourth section that is connected to a tie rod when installed in the ACM; a fifth section that is between the second section and the fourth section,

wherein forming the rotor base includes:

printing, layer by layer, the rotor base, by printing first and second thermoplastic polymer surfaces, respectively from first and second thermoplastic polymers, that are disposed against each other, the first thermoplastic polymer surface having a first coefficient of thermal expansion (CTE), and the second thermoplastic polymer surface having a second CTE;

forming a lower support section on the rotor base by printing, layer by layer, along the plurality of discrete sections of the rotor base a mixture of a third thermoplastic polymer and a catalyst formed with metal; and

forming an upper support section on the rotor by depositing on the lower support section, along each of the discrete sections, via electrolysis deposition, a metallic coating, to thereby control thermal expansion and contraction of the rotor along the discrete sections, to thereby make the rotor,

wherein forming the rotor base includes printing, layer by layer, a lattice of beads, wherein each of the beads has an outer surface formed by the first thermoplastic polymer surface and an inner surface formed by the second thermoplastic polymer surface, and wherein a void is formed in a center of each of the beads.

2 . The method of claim 1 , wherein the first and second CTEs differ from each other.

3 . The method of claim 1 , wherein:

the outer surface has first thickness and the inner surface has a second thickness that is greater than the first thickness.

4 . The method of claim 3 , wherein:

forming the rotor base includes printing the outer surface or the inner surface of each bead to include a first fiber having a fourth CTE that differs from the first and second CTEs.

5 . The method of claim 4 , wherein:

forming the rotor base includes printing the outer surface to include the first fiber having the fourth CTE and the inner surface to include a second fiber that that has a fifth CTE that differs from each of the other CTEs.

6 . The method of claim 5 , wherein the CTEs, other than the fourth and fifth CTEs, are the same as each other.

7 . The method of claim 5 , wherein the first fiber and the second fiber differ from each other, each being one of metallic, carbon or Kevlar fibers.

8 . The method of claim 1 , wherein:

forming the rotor base includes printing, layer by layer, a reinforcing fibrous string on each bead, wherein the string extends linearly across the bead, over the void of the bead.

9 . The method of claim 1 , wherein forming the rotor base includes:

printing the first thermoplastic polymer surface to provide a first CTE gradient; and

printing the second thermoplastic polymer surface to provide a second CTE gradient.

10 . The method of claim 9 , wherein:

the first and second gradients change in a thickness direction of the rotor base, and at an interface between the first and second thermoplastic polymer surfaces, the CTEs are the same as each other; or

the first and second gradients change in a circumferential direction, and at the interface between the first and second thermoplastic polymer surfaces, the CTEs differ from each other.

11 . A method of forming a rotor for an air cycle machine (ACM), the method comprising:

forming a rotor base having a plurality of discrete sections including: a first section that is adjacent to a diffuser shroud when installed in the ACM; a second section that forms a seal and is disposed against an aft frame member when installed in the ACM; a third section that is connected to a compressor rotor shaft when installed in the ACM; a fourth section that is connected to a tie rod when installed in the ACM; a fifth section that is between the second section and the fourth section,

wherein forming the rotor base includes:

printing, layer by layer, the rotor base, by printing first and second thermoplastic polymer surfaces, respectively from first and second thermoplastic polymers, that are disposed against each other, the first thermoplastic polymer surface having a first coefficient of thermal expansion (CTE), and the second thermoplastic polymer surface having a second CTE;

forming a lower support section on the rotor base by printing, layer by layer, along the plurality of discrete sections of the rotor base a mixture of a third thermoplastic polymer and a catalyst formed with metal; and

forming an upper support section on the rotor by depositing on the lower support section, along each of the discrete sections, via electrolysis deposition, a metallic coating, to thereby control thermal expansion and contraction of the rotor along the discrete sections, to thereby make the rotor,

wherein forming the rotor base includes printing, layer by layer, a continuous structure having voids, where the continuous structure is formed by the first thermoplastic polymer surface, and each of the voids is lined with the second thermoplastic polymer surface.

12 . The method of claim 1 , wherein the first and second thermoplastic polymer surfaces are the same as each other.

13 . The method of claim 1 , wherein the first thermoplastic polymer surface is Acrylonitrile butadiene styrene (ABS).

14 . The method of claim 1 , wherein the catalyst is palladium(II) chloride (PdCl 2 ).

15 . The method of claim 1 , including utilizing stereolithography (SLA) or fused deposition modeling (FDM).