JP7612840B2 - Automatic threading fiber placement head - Google Patents

Description

[0001] This application relates to a fiber placement machine, and more particularly to a fiber placement head that threads a composite tape from a spool through the head.

[0002] Fiber placement machines are used to create composite workpieces. Composite tape or composite material in the form of resin-impregnated fibrous material is applied by machine to a mold or mandrel in precise locations and lengths to collectively form the composite workpiece. The fiber placement machine moves a fiber placement head over the mold to precisely apply the composite tape to the final shape of the composite workpiece. As the fiber placement head moves, it leaves a number of composite tape segments, also called courses or tows, on the mold. As the composite tape segments are applied to the mold, the length of the segments is defined by a cutting action that separates the segments from the source of composite tape on the spool. Some workpieces involve the application of different sizes of composite tape that may be stored on or carried by other spools and/or fiber placement heads. If a different composite tape is needed, the robotic arm can release an existing fiber placement head that is threaded with one type or size of composite tape and select a new, different fiber placement head that is threaded with a different type or size of composite tape. Each fiber placement head can be pre-threaded with composite tape by a person, such as a machine operator, who manually threads one end of the composite tape from a spool into the fiber placement head. However, maintaining multiple fiber placement heads, each with a unique composite tape manually threaded, can increase cost and complexity.

[0003] In one embodiment, a fiber placement head assembly for applying a plurality of composite tape segments to a mold includes a fiber placement head configured to receive and apply a composite tape from a composite tape source to the mold. The assembly also includes one or more pneumatically operated conveyors coupled to the fiber placement head, each having an inlet configured to receive an end of a composite tape from a composite tape source, an outlet configured to provide the end of the composite tape to the fiber placement head, and one or more in-line vacuum conveyors configured to receive compressed fluid from the source and direct it toward the outlet to transport the end of the composite tape from the inlet to the outlet and into the fiber placement head.

[0004] In another embodiment, a fiber placement head assembly for applying a plurality of composite tape segments to a mold includes a fiber placement head configured to receive and apply a composite tape from a composite tape source to the mold, one or more pneumatically operated conveyors coupled to the fiber placement head, each having an inlet configured to receive an end of the composite tape, an outlet configured to provide the end to the fiber placement head, and one or more in-line vacuum conveyors configured to receive compressed fluid from a source and direct the compressed fluid toward the outlet to convey the end of the composite tape from the inlet to the outlet and into the fiber placement head, and a plurality of composite tape sources, each configured to releasably couple to the fiber placement head and including a pinch roller assembly that selectively supplies composite tape to the inlet of the pneumatically operated conveyor.

[0005] In yet another embodiment, a fiber placement head assembly for applying a plurality of composite tape segments to a mold includes a fiber placement head configured to receive and apply a composite tape from a composite tape source to the mold; a plurality of pneumatically operated conveyors coupled to the fiber placement head, each having an inlet configured to receive an end of the composite tape, an outlet configured to provide the end to the fiber placement head, and at least one in-line vacuum conveyor configured to receive compressed fluid from the source and direct it toward the outlet to transport the end of the composite tape from the inlet to the outlet and into the fiber placement head; and a plurality of composite tape sources, each configured to releasably couple to the fiber placement head and including a spool for storing the composite tape, a pinch roller assembly for selectively supplying the composite tape to the inlet of the pneumatically operated conveyor, and at least one direction change roller for contacting the composite tape between the source and the pinch roller assembly.

FIG. 1 is a perspective view of one embodiment of a fiber placement machine. [0007] FIG. 1 is a perspective view of one embodiment of a portion of a fiber placement head. FIG. 2 is another perspective view of an embodiment of a portion of a fiber placement head. FIG. 2 is another perspective view of an embodiment of a portion of a fiber placement head. FIG. 1 illustrates a cross-sectional view of one embodiment of a composite tape supply and pneumatically operated conveyor. FIG. 2 is another cross-sectional view illustrating an embodiment of a composite tape supply for an air-operated conveyor. FIG. 13 is a cross-sectional view illustrating another embodiment of a composite tape supply and pneumatically operated conveyor. FIG. 11 is another cross-sectional view illustrating another embodiment of a composite tape supply for an air-operated conveyor. FIG. 1 is a cross-sectional view of one embodiment of an air-operated conveyor.

[0015] A fiber placement machine may employ a robotic arm carrying a fiber placement head that releasably connects to a plurality of composite tape sources and automatically delivers composite tape from the composite tape sources to the fiber placement head. The fiber placement head may include piping that receives compressed air from an air-operated conveyor and extends from the composite tape source to the fiber placement head. The piping may deliver the composite tape from the source to the fiber placement head. After the fiber placement head attaches to the composite tape source, one end of the composite tape may be positioned at an inlet of the piping. The air-operated conveyor may draw the composite tape from the composite tape source at the inlet of the piping by supplying compressed air or fluid into the piping in one direction toward the fiber placement head and deliver the composite tape end to an outlet of the piping to rollers of the fiber placement head, where the composite tape may be applied to a mold controlled by the head during formation of a composite workpiece. Composite tapes used to create composite workpieces are often composed of fibrous material impregnated with resin, which gives the composite workpiece its strength after being heat activated. This is often referred to as a "prepreg" composite. One example of a composite material is carbon fiber.

[0016] One embodiment of a fiber placement machine 10 is shown in FIG. 1. The fiber placement machine 10 includes a robot arm 12 detachably coupled to a fiber placement head 14. The robot arm may be supported by a base 16 on which the robot arm moves linearly about an axis (x). A number of movable segments 18 may extend outwardly from the base 16, which may move, for example, by pivoting, rotating, or telescoping. The robot arm 12 may move about a number of axes relative to the base 16. For example, a first segment 18a may be rotatably coupled to the base 16 at one end such that the robot arm 12 may rotate about the base 16. A second segment 18b may be pivotally coupled to the first segment 18a, and a third segment 18c may be pivotally coupled to the second segment. A fourth segment 18d may be coupled to the third segment 18c and telescopically move away from and toward the third segment. The segments 18 may be moved relative to one another using a fluidic ram, an electric motor, or a combination thereof, or other drive elements to move the distal end of the robot arm 12 relative to a mold 20 or mandrel used to create a workpiece.

[0017] A number of composite tape sources 24 (sometimes referred to as creels) may be releasably coupled to the fiber placement head 14. In this embodiment, the robot arm 12 may move along an axis (a) such that the fiber placement head 14 is proximate to a first composite tape source 24a. The robot arm 12 may be coupled to the first composite tape source 24a such that the source 24a moves with the arm 12 as the arm 12 moves along the axis (a). The first composite tape source 24a may supply one type or size of composite tape to the fiber placement head 14. The fiber placement head 14, shown in more detail in FIG. 2, may draw one end of the composite tape supplied by the first composite tape source 24a toward its compression roller using an air-operated conveyor supplied by a compressed fluid, such as compressed air, and carried by the head 14. The air-operated conveyor is discussed in more detail below. The fiber placement head 14 receives composite tape from the first composite tape source 24a until a different type of composite tape is desired. The robot arm 12 can then move along the axis (a) to one end of its available travel range along the axis (a) and cut the composite tape and separate it from the first composite tape source 24a leaving the source 24a at the end of the axis (a). The robot arm 12 can then move away from the first composite tape source 24a towards the other end of the axis (a) where the arm 12 can couple with the second composite tape source 24b. The fiber placement head 14 can pull one end of the composite tape provided by the second composite tape source 24b towards its compression roller using an air-operated conveyor provided by compressed air and carried by the head 14 as described above.

[0018] A microprocessor (not shown) in communication with a computer readable storage medium having executable instructions may control the movement of the fluid ram, electric motor, or other drive elements, thereby controlling the operation and position of the movable segment 18 of the robot arm 12. The microprocessor may also control the supply of compressed fluid to the pneumatically operated conveyor as well as the roller assemblies. The microprocessor may be any type of device capable of processing electronic instructions, including microcontrollers, host processors, controllers, and application specific integrated circuits (ASICs). The microprocessor may be a dedicated processor used solely to provide control of the robot arm 12, or may be shared with other machine functions. The microprocessor executes various types of digitally recorded instructions, such as software or firmware programs stored in memory. Communication between the microprocessor and mechanisms, such as the fluid ram or electric motor, that move the robot arm may be via a communication bus. The robot arm 12 may move the fiber placement head 14 along three axes to position the head 14 for servicing or to apply composite tape to the form 20. This is one embodiment of a robotic arm 12 that may be used with a fiber placement head, but other embodiments of robotic arms or mechanical devices that apply composite tape may be used as well.

[0019] The end of the robot arm 12 distal to the base 16 can include a chuck 22 that releasably engages the fiber placement head 14. The chuck 22 and a portion of the fiber placement head 14 can have corresponding features such that the chuck 22 can releasably grip the fiber placement head 14. In one embodiment, the fiber placement head 14 includes a cylindrical shank that extends perpendicular to a surface of the head 14. The robot arm 12 can position the chuck 22 such that the chuck 22 engages the shank and the fiber placement head 14 is resiliently coupled to the arm 12.

[0020] As shown in Figures 3-4, the fiber placement head 14 may include an air operated conveyor 26 and a cut, clamp, restart (CCR) assembly 32 (shown in more detail in Figure 4). The CCR assembly 32 may include a compression roller 34 (or compression slide) that receives composite tape from the composite tape source 24 via the air operated conveyor 26 and applies it to the mold 20 to create the composite part. The composite tape may be fed by the composite tape source 24 and moved into the compression roller 34 for eventual application to the mold 20. In this embodiment, the air operated conveyor 26 is shown feeding composite tape to one lane of the fiber placement head 14. However, it should be understood that additional air operated conveyors 26 may be included in the fiber placement machine 10 to feed additional composite tape to separate lanes or separate fiber paths of the fiber placement head 14 as shown in Figure 4.

[0021] The fiber placement head 14 may include a CCR frame 40 for supporting the components of the fiber placement head 14, the CCR assembly 32, and the compression roller 34 that ultimately presses the composite tape web against the mold 20. Before reaching the compression roller 34, a portion of the composite tape may pass through an upper feed section 42 and another portion of the composite tape may pass through a lower feed section 44. The upper feed section 42 may process the even numbered composite tapes and the lower feed section 44 may process the odd numbered composite tapes that meet at the compression roller 34. As an example, for a fiber placement head 14 having eight fiber paths or lanes, the upper feed section 42 may process the composite tapes identified by numbers 2, 4, 6, and 8, while the lower feed section 44 may process the composite tapes identified by numbers 1, 3, 5, and 7. The upper feed section 42 and the lower feed section 44 may be separated by an angle (α). A plurality of lane assemblies 54 may be included in the upper and lower feed portions 42, 44. Each of the upper and lower feed portions 42, 44 may include a manifold 64 for receiving a plurality of mounting bases 52, which may releasably receive the plurality of lane assemblies 54. The mounting bases 52 may include a valve fitting 68, which aligns the bases 52 with respect to the manifold 64 and releasably couples the plurality of lane assemblies 54 to the fiber placement head 14. The valve fitting 68, such as a ball lock, serves to align a fluid path 66 from the mounting bases 52 to the manifold 64 and to form a fluid-tight seal with the bases 52.

[0022] An electromechanical valve 62 may abut the lane assembly 54 and may be coupled to the mounting base 52. Each lane assembly 54 may abut a solenoid valve 62 such that the valve 62 selectively supplies compressed air to the assembly 54 for actuation. The mounting base 52 may be coupled to a manifold 64, with a fluid path directing compressed air from a source (not shown) through the electromechanical valve 62 and ultimately to the lane assembly 54 coupled to the base 52. The compressed air may be selectively supplied to the lane assembly 54 by the solenoid valve 62 directing air from the manifold 64. In one embodiment, the solenoid valve 62 includes a solenoid that receives a voltage controlled by a switch that a microprocessor opens and closes to control actuation of the lane assembly 54. An air-operated conveyor 26 including a plurality of tubes may be coupled to the manifold 64 such that the outlet or output 90 of the tube is fluid-tightly connected to the manifold 64. The tubes of the air-operated conveyor 26 can deliver fiber tows to the CCR assembly 32 without manual assistance from an operator. In some embodiments, a number of vent holes 100 can be formed at the tube outlet 90 adjacent the manifold 64. These vent holes 100 can facilitate the flow of compressed air through the tubes and aid in the movement of the fiber tows through the tubes.

5-6, one embodiment of the composite tape source 24 and the pneumatically operated conveyor 26 is shown. The composite tape source 24 includes a supply spool 70 carrying the composite tape, a stationary direction changing roller 72, a dancer-mounted direction changing roller 74, a pinch roller assembly 76, and a cutting assembly 78. The composite tape may be wound on the supply spool 70, which is mounted on a spindle (not shown) carried by the composite tape source 24. The spindle may be fixed in position relative to the composite tape source 24. A clutch may be coupled to the spindle to selectively enable rotation of the spindle and to maintain a desired amount of tension on the composite tape leaving the supply spool 70. The pinch roller assembly 76 includes a brake roller 78 and a motive roller 80, at least one of which may have a movable axis of rotation such that a radially outer surface of the brake roller 80 may be brought close to a radially outer surface of the motive roller 82 for engagement with both sides of the composite tape strand. That is, the axis of rotation may slide along a linear path. The brake roller 80 may be allowed to rotate or may be held stationary without rotation depending on whether the composite tape is being presented to the air operated conveyor 26. A clutch may be included in the brake roller 80 and selectively actuated to allow the brake roller 80 to rotate or to hold the brake roller 80 stationary. The motive roller 82 may be coupled with an electric motor that selectively rotates the motive roller 82 to move the composite tape toward the air operated conveyor 26. The dancer-mounted direction-changing roller 74 may be mounted on a spindle (not shown) that is movable along an axis (d) and biased in one direction to maintain a desired amount of tension on the composite tape between the pinch roller assembly 76 and the composite tape supply 24. The bias may be generated passively, such as by a spring, or actively by any of a variety of mechanisms, such as a fluid ram or a solenoid. The dancer-mounted direction-changing roller 74 may maintain a desired amount of tension on the composite tape removed from the supply spool 70.

[0024] The composite tape source 24 may be carried by a supply spool 70 and threaded around a dancer mounted redirecting roller 74, a stationary redirecting roller 72 with one end of the composite tape engaging both a brake roller 80 and a motive roller 82. After the robotic arm 12 moves the fiber placement head 14 so that the composite tape source 24 is coupled with the head 14, a pinch roller assembly 78 may move one end of the composite tape to an inlet 82 at the end of the air operated conveyor 26 closest to the source 24. The air operated conveyor 26 may include at least one segment of tubing 86 extending from the composite tape source 24 to the fiber placement head 14. The tubing may be implemented as any of a variety of materials, such as plastic, one example includes PTFE. The conveyor 26 includes one or more in-line vacuum conveyors 88 somewhere in the segment of piping 86 that receive compressed fluid from a source (not shown) and direct it toward the fiber placement head 14. The pneumatically operated conveyor 26 includes an outlet 90 (shown in FIG. 3) near the fiber placement head 14, where the composite tape can be delivered. In one embodiment, the outlet 90 is positioned adjacent to the upper feed rollers 46 or the lower feed rollers 48.

[0025] Another embodiment of the composite tape source 24 and pneumatically operated conveyor 26 is shown in Figures 7-8. The embodiment shown in Figures 7-8 is similar to that shown in Figures 5-6, but does not have the pinch roller assembly 76. Instead, the pinch roller assembly may be replaced with a passive direction changing roller 82'.

9, one embodiment of the in-line vacuum conveyor 88 may include an inlet 92, an outlet 94, a fluid feed hole 96, and a number of fluid jets (not shown) that receive compressed fluid at the fluid feed hole 96 and direct it towards the fiber placement head 14 and the outlet 90 of the conveyor 26. The outlet 90 and/or the inlet 92 may fit inside the inner diameter of the tubing 86 and be coupled with a hose clamp. Or, in other embodiments, the outlet 90 and/or the inlet 92 may be threaded with corresponding threads on the tubing 86. The flow of compressed fluid generated by the in-line vacuum conveyor 88 towards the fiber placement head 14 may create a vacuum at the inlet of the pneumatically operated conveyor 26 adjacent the composite tape source 24, which may carry the end of the composite tape to the fiber placement head 14 and out the outlet without human assistance. One embodiment of the in-line vacuum conveyor 88 is described using the name "Line Vac®" and is commercially available from Exair. While the above embodiment shows one air-operated conveyor and one supply source, it should be understood that different embodiments may use multiple air-operated conveyors, such as one air-operated conveyor for each of multiple composite tapes that are simultaneously applied to the mold by the fiber placement head. Or, in some embodiments, one segment of piping 86 may include two or more in-line vacuum conveyors 88.

[0027] A cutting assembly 78 including an anvil 98 and a reciprocating cutting blade 100 may be positioned between the pinch roller assembly 76 and the air-operated conveyor 26. When the cutting blade 100 is spaced apart from the anvil 98, the composite tape may pass therebetween on its way to the air-operated conveyor 26. The pinch roller assembly 76 may move the composite tape 26 between the cutting blade 100 and the anvil 98. The cutting blade 100 may be passed against the anvil 98 to cut the composite tape. The composite tape may be cut when the robotic arm 12 separates from the composite tape source 24 and transfers it to a storage position.

[0028] It should be understood that the foregoing is a description of one or more embodiments of the present invention. The present invention is not limited to the specific embodiments disclosed herein, but rather is defined solely by the following claims. Furthermore, the statements contained in the above description are of specific embodiments and should not be construed as limitations on the scope of the present invention or on the definition of terms used in the claims, unless the term or phrase is expressly defined above. Various other embodiments, as well as various changes and modifications to the disclosed embodiments, will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to be included within the scope of the appended claims.

[0029] In this specification and claims, the terms "e.g.," "for example," "for instance," "such as," and "like," as well as the verbs "comprising," "having," "including," and other verb forms thereof, when used in conjunction with a list of one or more components or other items, should each be construed as open-ended, that is, the list should not be considered to exclude other additional components or items. Other terms should be construed using the broadest reasonable meaning of those terms, unless those terms are used in a context that requires a different interpretation.

Claims (8)

1. A fiber placement head assembly for applying a plurality of composite tapes to a mold, comprising:
a fiber placement head configured to receive a composite tape from a composite tape source and apply the composite tape to the form;
one or more pneumatically operated conveyors coupled to the fiber placement head, each pneumatically operated conveyor having an inlet configured to receive an end of a composite tape, an outlet configured to provide the end to the fiber placement head, and one or more conveyors configured to receive compressed fluid from a source and direct the compressed fluid toward the outlet to transport the end of the composite tape from the inlet to the outlet and into the fiber placement head;
a plurality of composite tape supplies, each of the composite tape supplies configured to couple with the fiber placement head and including a pinch roller assembly that selectively supplies composite tape to the inlet of the pneumatic conveyor;
1. A fiber placement head assembly comprising: The fiber placement head assembly of claim 1 , wherein the fiber placement head comprises a plurality of fiber paths and is coupled to a plurality of pneumatically operated conveyors. 2. The fiber placement head assembly of claim 1, wherein the pneumatically operated conveyor comprises a segment of piping having the inlet and the outlet and having one or more conveyors configured to transport the material to the inlet , to the outlet, or between the inlet and the outlet. The fiber placement head assembly of claim 1 , wherein the composite tape supply comprises a pinch roller assembly and a cutting assembly. The fiber placement head assembly of claim 4 , wherein the composite tape supply comprises a direction changing roller that contacts the composite tape between the pinch roller assembly and the cutting assembly. 1. A fiber placement head assembly for applying a plurality of composite tapes to a mold, comprising:
a fiber placement head configured to receive a composite tape from a composite tape source and apply the composite tape to the form;
a plurality of pneumatically operated conveyors coupled to the fiber placement head, each of the pneumatically operated conveyors having an inlet configured to receive an end of a composite tape, an outlet configured to provide the end to the fiber placement head, and at least one conveyor configured to receive compressed fluid from a source and direct the compressed fluid toward the outlet to transport the end of the composite tape from the inlet to the outlet and into the fiber placement head;
a plurality of composite tape supplies, each of the composite tape supplies configured to couple with the fiber placement head and including a spool for storing a composite tape, a pinch roller assembly for selectively supplying a composite tape to the entrance of the pneumatic conveyor, and at least one direction change roller for contacting the composite tape between the supply and the pinch roller assembly;
1. A fiber placement head assembly comprising: The fiber placement head assembly of claim 6 , wherein the fiber placement head comprises a plurality of fiber paths. 7. The fiber placement head assembly of claim 6, wherein the pneumatically operated conveyor comprises a segment of piping having the inlet and the outlet and having at least one conveyor configured to transport the inlet , to the outlet , or between the inlet and the outlet.

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