Method of vacuum forming a footwear upper

1. A method of forming a footwear upper, the method comprising:

applying an environmental pressure differential across a sheet of upper material disposed within a first compartment of a chamber to conform the sheet to a first portion of a footwear last disposed within the first compartment and to a second portion of the footwear last that is disposed separately from and spaced apart from the first portion within the first compartment, thereby forming a first component and a second component that are spaced apart from one another within the sheet;

wherein applying the environmental pressure differential includes:

drawing a vacuum on a first side of the sheet to thereby draw the first side into contact with the first portion and the second portion;

drawing a vacuum on a second side of the sheet while drawing the vacuum on the first side; and

after drawing the vacuum on the first side and drawing the vacuum on the second side, applying an atmospheric pressure on the second side;

wherein the first component has a first thickness that is consistent along an entirety of the first component, and further wherein the second component has a second thickness that is equal to the first thickness and is consistent along an entirety of the second component; and

joining the first component and the second component to form the footwear upper.

2. The method of claim 1 , wherein forming the first component includes forming a medial half of the footwear upper and wherein forming the second component includes forming a lateral half of the footwear upper; and

wherein joining includes forming a seam between the medial half and the lateral half.

3. The method of claim 2 , wherein joining the medial half of the footwear upper to the lateral half of the footwear upper includes affixing at least one reinforcing strip to the medial half of the footwear upper and the lateral half of the footwear upper at the seam.

4. The method of claim 2 , wherein joining includes welding the medial half to the lateral half to form a thermal bond between the medial half and the lateral half.

5. The method of claim 1 , further including increasing the environmental pressure differential by pressurizing the second side to a pressure above the atmospheric pressure.

6. A method of forming a footwear upper, the method comprising:

positioning a sheet of upper material having a first side and a second side within a chamber, the sheet dividing the chamber into a first compartment on the first side and a second compartment on the second side;

positioning a footwear last having a first portion and a second portion that is separate from, spaced apart from, and non-contiguous with the first portion in the first compartment on the first side;

applying an environmental pressure differential across the sheet wherein a first environmental pressure in the first compartment is lower than a second environmental pressure in the second compartment;

wherein applying the environmental pressure differential includes:

drawing a vacuum in the first compartment;

drawing a vacuum in the second compartment while drawing the vacuum in the first compartment; and

after drawing the vacuum in the first compartment and drawing the vacuum in the second compartment, applying the second environmental pressure on the second side;

wherein the environmental pressure differential draws the sheet against the footwear last thereby forming a first component and a second component that are spaced apart from one another within the sheet;

wherein the first component has a first thickness that is consistent along an entirety of the first component, and further wherein the second component has a second thickness that is equal to the first thickness and is consistent along an entirety of the second component; and

joining the first component and the second component to form the footwear upper.

7. The method of claim 6 , wherein joining includes forming a one-piece footwear upper.

8. The method of claim 6 , wherein forming the first component includes forming a medial portion of the footwear upper and wherein forming the second component includes forming a lateral portion of the footwear upper.

9. The method of claim 8 , further including:

joining the medial portion and the lateral portion to thereby form a seam; and

fixedly attaching the footwear upper to a sole structure to thereby form an article of footwear.

10. The method of claim 9 , wherein joining the medial portion to the lateral portion includes affixing at least one reinforcing strip to the medial portion and the lateral portion at the seam.

11. The method of claim 9 , wherein joining includes welding the medial portion to the lateral portion to form a thermal bond between the medial portion and the lateral portion.

12. The method of claim 6 , further including increasing the environmental pressure differential by pressurizing the second compartment to a pressure above the second environmental pressure.

13. A method of forming a footwear upper, the method comprising:

positioning a sheet of upper material having a first surface on a first side and a second surface on a second side within a chamber, the sheet dividing the chamber into a first compartment on the first side and a second compartment on the second side;

positioning a footwear last having a first portion and a second portion that is separate from the first portion in the first compartment on the first side;

applying an environmental pressure differential across the sheet, wherein a first environmental pressure in the first compartment is lower than a second environmental pressure in the second compartment;

wherein applying the environmental pressure differential includes:

drawing a vacuum in the first compartment;

drawing a vacuum in the second compartment while drawing the vacuum in the first compartment; and

after drawing the vacuum in the first compartment and drawing the vacuum in the second compartment, applying the second environmental pressure on the second side;

wherein gases under the second environmental pressure exert a force against the entire second surface within the first compartment, thereby pressing the first side against the footwear last and conforming the sheet to the footwear last to form a first component and a second component that are spaced apart from one another within the sheet;

wherein the first component has a first thickness that is consistent along an entirety of the first component, and further wherein the second component has a second thickness that is equal to the first thickness and is consistent along an entirety of the second component; and

joining the first component and the second component to form the footwear upper.

14. The method of claim 13 , wherein joining includes forming a one-piece footwear upper.

15. The method of claim 13 , wherein forming the first component includes forming a medial portion of the footwear upper and wherein forming the second component includes forming a lateral portion of the footwear upper.

16. The method of claim 15 , further including:

joining the medial portion to the lateral portion to thereby form a seam; and

fixedly attaching the footwear upper to a sole structure to thereby form an article of footwear.