Fiber Placement Machine Including Composite Tape Film Removal

Abstract

A fiber placement head for applying a plurality of composite tape segments to a mold includes a supply roll for storing a composite tape having a backing film and supplying the composite tape to the fiber placement head, a film roll for receiving the backing film from the composite tape removed from the film roll, an electric motor for rotating the supply roll or film roll, and a slip clutch coupled to the supply roll or film roll, which allows for relative displacement of the angular position of the film roll with respect to the angular position of the supply roll.

Description

[Technical field]

[0001] This application relates to fiber placement machines, and more particularly to a fiber placement head that efficiently manages the removal of a film from a composite tape. [Background technology]

[0002] Fiber placement machines are used to create composite workpieces. Composite material in the form of resin-impregnated fibrous matter is mechanically applied 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 multiple composite tape segments, also called courses or tows, on the mold. Multiple composite tape strands may be applied simultaneously as part of a course, but the fiber placement head can control each of the tows individually as part of applying the course. The automated application of these composite tape segments to the mold involves the cooperation of a diverse array of machines that hold, move, and ultimately cut the composite tape. Summary of the Invention [Problem to be solved by the invention]

[0003]

[0003] The composite fiber tape used by the fiber placement machine may be impregnated with a resin that is activated by heat applied after or during application to the mold. The composite fiber tape may be organized on a roll or tube so that it remains wound on the roll or tube until it is needed. One end of the tape is then fed into the fiber placement machine, which pulls the composite fiber tape from the roll / tube. However, the resin pre-impregnated in the composite fiber tape may be somewhat sticky, so a film - sometimes called a plastic interleave - may be positioned on one side of the tape to prevent one section of the composite fiber tape from touching another section of the tape when the tape is stored on the tube / spool. This configuration may prevent sections of the composite fiber tape from unintentionally adhering to each other. Prior to application to the mold or mandrel, the film is removed from the tape. It is beneficial to control when this film is removed from the composite fiber tape that is applied to the mold / mandrel. [Means for solving the problem]

[0004]

[0004] In one embodiment, a fiber placement head for applying multiple composite tape segments to a mold includes a supply roll for storing a composite tape having a backing film and supplying the composite tape to the fiber placement head, a film roll for receiving the backing film from the composite tape being removed from the film roll, an electric motor for rotating the supply roll or film roll, and a slip clutch connected to the supply roll or film roll, which allows relative displacement of the angular position of the film roll with respect to the angular position of the supply roll. [Brief description of the drawings]

[0005] [Figure 1] 1 is a perspective view of one embodiment of a fiber placement machine. [Diagram 2]

[0006] FIG. 2 is another perspective view of an embodiment of a fiber placement head. [Diagram 3]

[0007] FIG. 2 is a perspective view of one embodiment of a portion of a fiber placement head. [Figure 4]

[0008] 1 is a profile view of one embodiment of a portion of a fiber placement head. [Diagram 5]

[0009] FIG. 2 is another perspective view of an embodiment of a portion of a fiber placement head. [Figure 6]

[0010] FIG. 2 is another perspective view of an embodiment of a portion of a fiber placement head. [Figure 7]

[0011] 1 is a profile view of one embodiment of a portion of a fiber placement head. [Figure 8]

[0012] 1 is a profile view of one embodiment of a portion of a fiber placement head. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0006]

[0013] A fiber placement machine may include a fiber placement head carrying one or more spools of composite tape that are fed for application to a mold. Multiple composite tape segments may be applied to a mold to collectively form a composite part. As the composite tape is fed from the spool, a backing film (plastic interleave) may be removed from the tape. A supply spindle may carry the supply spool, and a separate film spool carried by a film spindle may receive the backing film removed from the composite tape as the tape is pulled from the supply spool. The film spindle may be connected to an electric motor that serves to rotate the film spindle and maintain tension on the backing film that is collected by the film spool. Initially, when the supply spool of composite tape contains a starting amount of tape, the supply spool exists at an initial diameter. As the composite tape is removed from the supply spool and the backing film is received by the film spindle, the diameter of the supply spool decreases and the diameter of the film spool increases. Changing the diameters of the supply spool and the spindle spool can change the diameter ratio of the spools. A slip clutch can be coupled to the supply spindle or the film spindle so that the electric motor that rotates the film spindle can rotate at a greater angular velocity than the supply spindle and the film spindle to maintain tension on the composite tape and backing film as the backing film is removed from the tape.

[0007]

[0014] 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 telescopingly move away from and towards the third segment. The segments 18 can be moved relative to one another using a fluid 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.

[0008]

[0015] 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 motion and position of the movable segment 18 of the robotic arm 12. 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 robotic 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 robotic arm, may occur via a communication bus.

[0009]

[0016] The robot arm 12 can 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 the robot arm 12 that can be used with a fiber placement head, although other embodiments of a robot arm or mechanical device that applies composite tape can be used as well. 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.

[0010]

[0017] As shown in FIGS. 2-6 , fiber placement head 14 can include a creel frame 24, a number of spools 26 that carry composite tape as a source of composite tape for head 14, and a cut, clamp, restart (CCR) assembly 32. CCR assembly 32 can include a compression roller 34 (or alternatively, a compression slide) that can receive composite tape from spool 26 and apply it to mold 20 to create a composite part. Creel frame 24 includes a number of exterior surfaces 36 and a spindle 38 mounted perpendicular to exterior surfaces 36. Spindle 38 can be moved to generate tape tension in some embodiments using a pneumatically, mechanically, or fluidically controlled dancer element that helps maintain tension on the composite tape as the tape is applied to mold 20. More specifically, as shown in Figures 3-6, fiber placement head 14 may include a supply spool 26a carried by a supply spindle 38a and a film spool 26b carried by a film spindle 38b. A dancer roll 28 may also be carried by fiber placement head 14 to help manage tension in the composite tape as it is unwound from supply spool 26a. In one embodiment, dancer roll 28 may move along a linear slide 29 in response to a force applied by dancer arm 30, which will be discussed in more detail below. The composite tape may be unwound from supply spool 26a and moved over dancer roll 28 into a compression roller 34 onto film spool 26b where the backing film is collected for eventual application to mold 20.

[0011]

[0018] A portion of the inner surface 42 of the fiber placement head 14 is shown in FIGS. 3-4. A number of components included in the fiber placement head 14 are shown proximate the inner surface 42. For example, the fiber placement head 14 can include a rotational drive 46 that mechanically connects the film spindle 38b to the supply spindle 38a and a supply spool tensioner 50. The supply spool tensioner 50 can include an electric motor for rotating the supply spindle 38a. In this embodiment, the rotational drive 46 can include an endless loop 47, such as a belt or chain, that engages both a film pulley 54 attached to the output shaft 45 of the film spool 26b and a supply pulley 52 that is ultimately coupled to the supply spindle 38a via a slip clutch 48. In some embodiments, the slip clutch 48 can be positioned adjacent an axial end of the supply spool 26a, and in still other embodiments, the clutch 48 can be positioned radially inward of the composite material carried by the supply spool 26a. The diameters of the supply pulley 52 and the film pulley 54 may be selected to maintain a particular ratio. This will be discussed in more detail below. The film pulley 54 and the supply pulley 52 may include grooved axially outer surfaces to receive a correspondingly shaped endless loop such that increased tension correspondingly increases friction between the endless loop 47 and the pulleys 52, 54. Or, in another embodiment, the pulleys 52, 54 may include radially outwardly directed teeth that engage with an endless loop implemented as a chain. Tension on the endless loop may be maintained using a dancer idler 58 that includes an idler pulley that is biased into contact with the endless loop. However, other embodiments are possible in which the rotary drive is implemented as a gear connection between the output shaft 45 and the supply spindle 38a. In this embodiment, the supply spool tensioner 50 may maintain a prescribed level of torsional resistance on the supply spindle 38a. The supply spool tensioner 50 may include a servo motor having an output coupled to the endless loop 47, which engages a tension pulley 56 mounted on one end of the supply spindle 38a.However, other embodiments are possible in which the servo motor is axially aligned with the supply spindle 26a and includes a series gear reducer coaxial with the spindle's axis of rotation.

[0012]

[0019] The slip clutch 48 may include a clutch input 60 that couples with the supply pulley 52 and a clutch output 62 that engages the supply spindle 38a to rotate it. The clutch input 60 maintains a fixed angular position relative to the clutch output 62 until a certain amount or level of torque is applied to the clutch input 60. Once the torque level is exceeded, the slip clutch 48 allows the clutch input 60 to change angular position relative to the clutch output, thereby limiting the amount of torque transmitted from the clutch input 60 to the clutch output 62. The slip clutch may be implemented in any of a variety of ways, and the amount of torque at which an angular displacement occurs may be selected. For example, one or more friction pads may be positioned along the axis of rotation between the clutch input 60 and the clutch output 62. The clutch input 60 and the clutch output 62 may couple with opposing ends of the friction pads. In some embodiments, an axial thread used with a collar can be used to increase or decrease the pressure of the friction pads against one another and thereby increase or decrease the torque value at which the clutch output 62 is angularly displaced relative to the clutch input 60. The ratio of the diameter of the supply pulley 52 to the diameter of the film pulley 54 can be selected such that the clutch input 60 is angularly displaced relative to the clutch output 62 while the electric motor is running regardless of whether the supply spool 26a is in an initial state (initial diameter) where the composite tape is fully wound or whether the supply spool 26a is in a depleted state where a significant amount of backing film is wound on the film spindle 38b.

[0013]

[0020] Turning to FIG. 7, a profile view of one embodiment of the supply spool 26a in an initial state is shown, and in FIG. 8, a profile view of one embodiment of the supply spool 26a in an exhausted state is shown. In FIG. 7, the supply spool 26a is wound to full capacity with composite tape 64. In this embodiment, the supply spool 26a at full capacity may have a diameter of 8 inches, and the film spool 26b when empty or nearly empty may have a diameter of 2.5 inches. Considering the angular velocity of the output shaft 45, the ratio of the supply spool 26a at full capacity to the empty film spool 26b is 3.2:1. As the composite tape 64 is fed into the fiber placement head 14 and deposited on the mold 20, the diameter of the supply spool 26a decreases, while the diameter of the film spool 26b increases as the film spool 26b receives the backing film 66 removed from the composite tape 64. When the composite tape 64 is removed from the supply spool 26b and the backing film 66 from the removed tape 64 is wound onto the film spool 26b, the diameter of the supply spool 26a is 3 inches, while the diameter of the film spool 26b is 6.5 inches. The ratio of the depleted supply spool to the film spool filled with backing tape 66 is 1:2.2. The electric motor can rotate the supply pulley 52 relative to the film pulley 54 at an angular velocity such that in one embodiment there is a 4:1 ratio, so that despite changes in the diameters of the supply spools 26a and 26b, the supply spindle 38a can be overdriven such that the clutch input 60 is angularly displaced relative to the clutch output 62 to maintain tension in the backing film 66 as it is removed from the composite tape 64. At an output shaft angular speed of 2,400 revolutions per minute (RPM), the supply spool 26a can rotate at an angular speed of 95.5 RPM and the film spool 26b can rotate at an angular speed of 306 RPM.After all or nearly all of the composite tape 64 has been drawn off of the supply spool 26a, the supply spool 26a may rotate at an angular rotational speed of 241 RPM and the film spool may rotate at an angular rotational speed of 118 RPM.

[0014]

[0021] 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 the terms used in the claims, unless the terms or phrases are 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.

[0015]

[0022] In this specification and claims, the terms "eg," "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

1. a fiber placement head for applying a plurality of composite tape segments to a mold, the fiber placement head comprising: a supply roll for storing a composite tape having a backing film mounted on a spool carried by a creel frame of the fiber placement head and for supplying the composite tape to the fiber placement head; a film roll mounted on a spool separate from the spool carried by the creel frame of the fiber placement head for receiving the backing film from the composite tape, the composite tape being removed from the film roll; an electric motor for rotating the supply roll or the film roll; a slip clutch carried by the creel frame and connected to the supply roll or the film roll, the slip clutch allowing a relative displacement of the angular position of the film roll relative to the angular position of the supply roll in response to a changed diameter of the supply roll relative to a changed diameter of the film roll; 1. A fiber placement head comprising:

2. 10. The fiber placement head of claim 1, further comprising a dancer roll that receives a composite tape from the supply roll and feeds the composite tape onto an outer surface of the film roll while maintaining tension on the composite tape.

3. 10. The fiber placement head of claim 1, wherein the supply pulley is rotated at an angular velocity relative to the film pulley such that a 4:1 ratio exists such that the supply spindle can be driven at an increased speed despite changes in diameter of the supply spool and the film spool.

4. The fiber placement head of claim 3 , wherein a rotational drive includes the feed pulley, the film pulley, and an endless loop.

5. The fiber placement head of claim 1 , further comprising a film spindle for carrying the film roll and receiving rotational input from the electric motor.

6. The fiber placement head of claim 1 , further comprising a supply spindle for carrying the supply roll and receiving rotational input from the electric motor.

Images