Method for forming an impeller housing for an appliance

1. A method for forming a unitary housing for an impeller of a dryer appliance, comprising:

establishing three-dimensional information of the unitary housing;

converting the three-dimensional information of the unitary housing from said step of establishing into a plurality of slices, each slice of the plurality of slices defining a respective cross-sectional layer of the unitary housing; and

successively forming each cross-sectional layer of the unitary housing with an additive process;

wherein, after said step of successively forming: (1) the unitary housing has a transition duct extending between a volute of the unitary housing and an exhaust exit of the unitary housing; (2) the transition duct has an inlet cross-section immediately downstream of the volute of the unitary housing and an outlet cross-section at the exhaust exit of the unitary housing; (3) the inlet cross-section has a curvilinear trapezoidal shape; (4) the outlet cross-section has a circular shape; (5) the transition duct continuously varies from the inlet cross-section to the outlet cross-section along a length of the transition duct; (6) each of the cross-sections of the transition duct vary less than five percent per millimeter from an adjacent cross-section of the transition duct along the length of the transition duct from the inlet cross-section to the outlet cross-section; and (7) the inlet cross-section of the transition duct comprises a curved upper wall, a linear bottom wall and a pair of parallel linear sidewalls with the linear sidewalls of the pair of parallel linear sidewalls extending between and connecting the curved upper wall and the linear bottom wall and with the linear bottom wall oriented perpendicular to the pair of parallel linear sidewalls.

2. The method of claim 1 , wherein the additive process comprises at least one of fused deposition modeling, selective laser sintering, stereolithography, and digital light processing.

3. The method of claim 1 , further comprising mounting a cover plate to the unitary housing such that the cover plate is positioned over the volute of the unitary housing and the inlet cross-section of the transition duct after said step of successively forming.

4. The method of claim 3 , wherein the cover plate defines an entrance for receiving a flow of air into the volute of the housing.

5. The method of claim 3 , wherein the housing is constructed of plastic and the cover plate is constructed of metal.

6. The method of claim 1 , wherein the transition duct defines an inner radius of curvature and an outer radius of curvature between the inlet cross-section to the outlet cross-section after said step of successively forming, the inner radius of curvature being at least two inches and the outer radius of curvature being at least four inches.

7. The method of claim 6 , wherein the inner radius of curvature is at least four inches and the outer radius of curvature is at least eight inches.

8. The method of claim 1 , wherein the unitary housing comprises a single continuous piece of plastic after said step of successively forming.

9. A method for forming a unitary housing for an impeller of a dryer appliance, comprising:

establishing three-dimensional information of the unitary housing;

converting the three-dimensional information of the unitary housing from said step of establishing into a plurality of slices, each slice of the plurality of slices defining a respective cross-sectional layer of the unitary housing; and

successively forming each cross-sectional layer of the unitary housing with an additive process;

wherein, after said step of successively forming: (1) the unitary housing has a cylindrical portion configured for receiving the impeller; (2) the cylindrical portion has a volute; (3) the unitary housing has a transition duct extending between the volute of the cylindrical portion and an exhaust exit; (4) the transition duct has an inlet cross-section immediately downstream of the volute of the cylindrical portion and an outlet cross-section at the exhaust exit; (5) the inlet cross-section has a different shape than the outlet cross-section; (6) cross-sections of the transition duct continuously vary from the inlet cross-section to the outlet cross-section along a length of the transition duct; (7) each of the cross-sections of the transition duct vary less than five percent per millimeter from an adjacent cross-section of the transition duct along the length of the transition duct from the inlet cross-section to the outlet cross-section; (8) the unitary housing comprises a single continuous piece of plastic; and (9) the inlet cross-section of the transition duct has a curvilinear trapezoidal shape with a curved upper wall, a linear bottom wall and a pair of parallel linear sidewalls with the linear sidewalls of the pair of parallel linear sidewalls extending between and connecting the curved upper wall and the linear bottom wall and with the linear bottom wall oriented perpendicular to the pair of parallel linear sidewalls.

10. The method of claim 9 , wherein the additive process comprises at least one of fused deposition modeling, selective laser sintering, stereolithography, and digital light processing.

11. The method of claim 9 , further comprising mounting a cover plate to the unitary housing such that the cover plate is positioned over the volute of the unitary housing and the inlet cross-section of the transition duct after said step of successively forming.

12. The method of claim 11 , wherein the housing is constructed of plastic and the cover plate is constructed of metal.

13. The method of claim 9 , wherein the outlet cross-section has a circular shape or a rectangular shape.

14. The method of claim 9 , wherein the transition duct defines an inner radius of curvature and an outer radius of curvature between the inlet cross-section to the outlet cross-section after said step of successively forming, the inner radius of curvature being at least two inches and the outer radius of curvature being at least four inches.

15. The method of claim 14 , wherein the inner radius of curvature is at least four inches and the outer radius of curvature is at least eight inches.

16. The method of claim 9 , wherein the transition duct continuously varies from the inlet cross-section to the outlet cross-section along the length of the transition duct such that each cross-section of the transition duct along the length of the transition duct is dissimilar to an adjacent cross-section of the transition duct after said step of successively forming.

17. The method of claim 9 , wherein the unitary housing comprises a single continuous piece of plastic after said step of successively forming.