System and method for manufacturing off-axis prepreg material

1. An off-axis prepreg material manufacturing machine, comprising:

a robot configured to position a prepreg piece adjacent to an end of a prepreg layer;

an alignment system configured to sense a position of the prepreg piece relative to the prepreg layer and generate a position signal representative thereof;

a controller configured to receive the position signal and cause the robot to adjust the position of the prepreg piece such that an end edge of the prepreg piece and an end edge of the prepreg layer are in substantially abutting contact; and

at least one welding shoe configured to be translated along a top surface of the abutting end edges of the prepreg piece and prepreg layer and locally heat the abutting end edges and form a weld seam joining the prepreg piece to the prepreg layer.

2. The machine of claim 1 , wherein:

the alignment system comprises a vision system configured to detect a location and orientation of the end edge of the prepreg piece relative to the end edge of the prepreg layer.

3. The machine of claim 1 , wherein:

the alignment system comprises a vision system configured to detect a location and orientation of a side edge of the prepreg piece relative to the side edge of the prepreg layer.

4. The machine of claim 1 , wherein:

the alignment system includes a first pair of laser micrometers configured to measure the position of the end edges of the prepreg piece and prepreg layer relative to one another, and a second pair of laser micrometers configured to measure the position of side edges of the of the prepreg piece and prepreg layer relative to one another.

5. The machine of claim 1 , further comprising:

an input hopper configured to support a prepreg stack of prepreg pieces for pickup by the robot.

6. The machine of claim 1 , wherein:

the robot includes a vacuum head configured to use suction force to lift and retain the prepreg piece against the vacuum head.

7. The machine of claim 1 , wherein:

the at least one welding shoe comprises a pair of welding shoes initially positioned at an approximate midpoint of the prepreg layer width and each being translated toward one of opposing side edges of the prepreg piece and prepreg layer to apply heat to abutting end edges of the prepreg piece and prepreg layer and form the weld seam joining the prepreg piece to the prepreg layer.

8. The machine of claim 1 , further comprising:

a backing anvil configured to support the prepreg piece and prepreg layer against pressure applied by the at least one welding shoe onto the prepreg piece and prepreg layer during the forming of the weld seam.

9. The machine of claim 1 , further comprising:

a bridge configured to support the at least one welding shoe and being adjustably translatable along a lengthwise direction of the prepreg layer to position the welding shoe over abutting end edges of the prepreg piece and prepreg layer.

10. The machine of claim 1 , wherein:

an orientation of the at least one welding shoe is adjustable relative to a lengthwise direction of the prepreg layer.

11. The machine of claim 1 , further comprising:

an inspection system including at least one of the following:

a gap detector configured to detect a through-thickness gap in the weld seam joining the prepreg piece to the prepreg layer; and

an overlap sensor configured to detect an overlap in the weld seam.

12. An off-axis prepreg material manufacturing machine, comprising:

a robot configured to position a prepreg piece adjacent to an end of a prepreg layer;

an alignment system configured to sense a position of the prepreg piece relative to the prepreg layer and generate a position signal representative thereof; and

a controller configured to receive the position signal and cause the robot to adjust the position of the prepreg piece such that an end edge of the prepreg piece and an end edge of the prepreg layer are in substantially abutting contact; and

a welding system having one or more welding shoes configured to be translated along a top surface of abutting end edges of the prepreg piece and prepreg layer and locally heat the abutting end edges and form a weld seam joining the prepreg piece to the prepreg layer.

13. A method of manufacturing an off-axis thermoplastic prepreg material roll, comprising the step of:

positioning, using a robot, a prepreg piece adjacent to an end of a prepreg layer;

sensing, using an alignment system, a position of the prepreg piece relative to the prepreg layer and generating a position signal representative thereof;

receiving, at a controller, the position signal from the alignment system;

adjusting, using the robot under command of the controller, the position of the prepreg piece such that an end edge of the prepreg piece and an end edge of the prepreg layer are in substantially abutting contact prior to forming a weld seam joining the prepreg piece to the prepreg layer; and

translating at least one welding shoe along a top surface of abutting end edges of the prepreg piece and prepreg layer for locally heating the abutting end edges and form the weld seam.

14. The method of claim 13 , wherein the steps of sensing and adjusting the position of the prepreg piece comprise:

detecting, using a vision system, a location and orientation of an end edge of the prepreg piece relative to an end edge of the prepreg layer and generating the position signal representative thereof; and

adjusting, using the robot, the location and orientation of the prepreg piece such that the end edge of the prepreg piece and prepreg layer are in substantially abutting contact.

15. The method of claim 13 , wherein the steps of sensing and adjusting the position of the prepreg piece comprise:

detecting, using a vision system, a location and orientation of a side edge of the prepreg piece relative to a side edge of the prepreg layer and generating the position signal representative thereof; and

adjusting, using the robot, the location and orientation of the prepreg piece such that the side edge of the prepreg piece and prepreg layer are aligned.

16. The method of claim 13 , wherein:

the alignment system includes laser micrometers configured to measure the alignment of the end edge and/or side edge of the prepreg piece relative to the respective end edge and/or side edge of the prepreg layer.

17. The method of claim 13 , further comprising:

picking up, using a vacuum head of the robot, an uppermost prepreg piece from a prepreg stack in an input hopper.

18. The method of claim 13 , wherein the step of translating the at least one welding shoe along the top surface of abutting end edges comprises:

translating each of a pair of welding shoes from an approximate midpoint of a prepreg layer width toward one of opposing side edges of the prepreg piece and prepreg layer to form the weld seam joining the end edge of the prepreg piece to the end edge of the prepreg layer as a result of applying heat using the pair of welding shoes against the prepreg piece and prepreg layer.

19. The method of claim 18 , further comprising:

supporting, using a backing anvil, the prepreg piece and prepreg layer against pressure applied onto the prepreg piece and prepreg layer by the welding shoe during forming of the weld seam.

20. The method of claim 13 , further comprising:

clamping, using at least one clamp bar, at least one of the prepreg piece and the prepreg layer during welding of the end edges of the prepreg piece and the prepreg layer.

21. The method of claim 13 , further comprising:

inspecting the weld seam for at least one of:

a through-thickness gap in the weld seam; and

an overlap of the weld seam.

22. The method of claim 13 , wherein the step of forming the weld seam comprises

forming the weld seam along a direction non-perpendicular to a lengthwise direction of the prepreg layer and prepreg piece.