WO2011116191A1

WO2011116191A1 - Band width control for band forming apparatus

Info

Publication number: WO2011116191A1
Application number: PCT/US2011/028817
Authority: WO
Inventors: Craig Hyland; Ronald Roser; Robert Roser
Original assignee: Zoltek Companies, Inc.
Priority date: 2010-03-17
Filing date: 2011-03-17
Publication date: 2011-09-22

Abstract

An apparatus for controlling the width of a band of continuous fibers includes a controller coupled to one or more width adjusting devices for changing the orientation of the width adjusting devices. The apparatus may further include a width detection system that provides a width detection signal to the controller. The width detection system may include an optical sensor.

Description

Title: BAND WIDTH CONTROL FOR BAND FORMING APPARATUS

Technical Field

The present invention relates to a system and apparatus for controlling the width of a band of fibers. In particular, the present invention relates to a system and apparatus for fiber winding and placement.

Background

Conventional filament winding processes involve wrapping a rotating mandrel with continuous fiber. The surface of the rotating mandrel may be relatively uniform or may be contoured. The winding apparatus generally has the ability to alter the wind geometries and achieve different architectures. The fiber used may be prepreg, wound wet, or wound dry and used in conjunction with processes such as resin transfer molding.

Fiber placement is similar to filament winding in that it is a continuous process for fabricating composite shapes, by laying thermoset or thermoplastic

preimpregnated fiber bundles onto a mandrel or tool having concave or convex surfaces.

The continuous fibers used in filament winding and fiber placement systems may be arranged into a band prior to being wound or laid on the mandrel or tool. Band width can be controlled by varying the space between adjacent fiber bundles. By varying the width of the band during winding, it is possible to better conform the fibers to the surface of the mandrel or tool.

Additionally, producing fiber bands having uniform width is advantageous in preconditioning processes used for example in the manufacture of unidirectional preforms and in the manufacture of prepregs.

Summary

In one aspect of the invention there is provided a device for controlling the width of a band of fibers, the band of fibers containing a plurality of continuous fiber bundles. The device includes a guide roll arranged to guide a plurality of continuous fiber bundles drawn into the device from a supply thereof along a path; a first width adjuster arranged to spread or compact the fiber bundles accepted from the guide roll; a second width adjuster arranged along the path downstream of the first width adjuster to spread or compact the fiber bundles as a function of an orientation of the second width adjuster, the second width adjuster cooperating with the first width adjuster to form a band of fibers having the desired width and thickness; and a controller operatively coupled to at least the second width adjuster and configured to change the orientation of the second width adjuster.

In one embodiment, the second width adjuster includes a variable curvature device. In another embodiment, the second width adjuster includes a barrel cam.

The first width adjuster may also spread or compact the fiber bundles as a function of an orientation of the first width adjuster. The first width adjuster, in one embodiment, includes a variable curvature device. The controller may also be coupled to the first width adjuster and configured to change the orientation of the first width adjuster. The orientation of each of the first and second width adjusters may be changed independently of the other. Alternatively, the orientation of each of the first and second width adjusters may be changed in a predetermined coordinated manner.

In one embodiment, the device further includes a detection system disposed downstream of the second width adjuster and configured to detect the width of the band and output a width detection signal, wherein the controller changes the orientation of at least the second width adjuster as a function of the width detection signal output by the detection system.

In certain embodiments, the detection system of the method includes at least one optical sensor. The optical sensor may be a camera, a line camera, a fiber optic sensor, a charge-coupled device (CCD), or a complementary metal-oxide

semiconductor (CMOS).

In certain embodiment, the device further includes a rotary encoder disposed along the path and arranged to detect the speed of the fiber bundles drawn into the device and provide output to the controller, wherein the controller is further configured to change the orientation of at least the second width adjuster as a function of the speed detected by the encoder.

In another aspect of the invention, there is provided a delivery head assembly for a filament winding machine for applying a plurality of continuous fiber bundles in the form of a band onto a mandrel, the assembly including a device for controlling the width of a band of fibers, the device including a guide roll arranged to guide a plurality of continuous fiber bundles drawn into the device from a supply thereof along a path; a first width adjuster arranged to spread or compact the fiber bundles accepted from the guide roll; a second width adjuster arranged along the path downstream of the first width adjuster to spread or compact the fiber bundles as a function of an orientation of the second width adjuster, the second width adjuster cooperating with the first width adjuster to form a band of fibers having the desired width and thickness; and a controller operatively coupled to at least the second width adjuster and configured to change the orientation of the second width adjuster.

In one embodiment of the invention, there is provided a delivery head assembly for a filament winding machine for applying a plurality of continuous fiber bundles in the form of a band onto a mandrel. The delivery head assembly includes at least one variable curvature device for spreading or compacting the fiber bundles as a function of an orientation of the at least one variable curvature device to form a band having the desired width and thickness; a detection system for detecting the width of the band and for outputting a width detection signal; and a controller operatively coupled to the at least one variable curvature device for changing the orientation of the at least one variable curvature device as a function of the width detection signal output by the detection system.

In certain embodiments, the detection system includes at least one optical sensor. The optical sensor may be a camera, a line camera, a fiber optic sensor, a charge-coupled device (CCD), or a complementary metal-oxide semiconductor (CMOS).

In certain embodiments, the delivery head assembly includes at least two variable curvature devices. The controller is operatively coupled to the at least two variable curvature devices for changing the orientation of each variable curvature device as a function of the width detection signal. The orientation of each variable curvature device may be changed independently of the other, or in a predetermined coordinated manner.

In certain embodiments, the controller further controls the orientation of the at least one variable curvature device as a function of the speed at which the continuous fiber bundles are drawn through the delivery head assembly. The invention also includes a filament winding apparatus that includes the delivery head assembly for applying a plurality of continuous fiber bundles in the form of a band onto a mandrel.

In one aspect of the invention, there is provided a method of controlling the width of a band of continuous fibers. The method includes the steps of providing a plurality of continuous fibers; forming a band of fibers by compacting or spreading the plurality of continuous fibers with at least one variable curvature device, the width of the band being a function of an orientation of the at least one variable curvature device; detecting the width of the band; and automatically changing the orientation of the at least one variable curvature device in response to the detected width.

In certain embodiments, the detection system of the method outputs a width detection signal to a controller that is operatively coupled to the at least one variable curvature device.

Brief Description of the Drawings

FIG. 1 is a perspective view of an embodiment of a filament winding apparatus according to the present invention.

FIG. 2 is a front/side perspective view of an embodiment of a filament delivery head in accordance with the present invention.

FIG. 3 is a rear/side perspective view of the embodiment of the filament delivery head of FIG. 2.

FIG. 4 is a block diagram illustrating an embodiment of the band width controller operations of the present invention.

FIG. 5 is a perspective view of an embodiment of an apparatus for controlling the width of a band of fiber in accordance with the present invention.

FIG. 6 is a perspective view of the barrel cam of the apparatus shown in FIG.

5.

FIG. 7 is a block diagram illustrating another embodiment of the band width controller operations of the present invention.

Detailed Description

The invention is generally directed to an apparatus for controlling the width of a band of continuous fibers. Band width control allows fibrous materials to be more uniformly placed on parts, such as mandrels and tools, and is particularly useful for filament winding. The apparatus for controlling the width of the fiber band is also particularly useful in fiber band preconditioning operations used, for example, in the manufacture or prepreg or unidirectional preforms.

The apparatus includes at least one width adjuster that spreads or compacts the fiber bundles as a function of the orientation of the adjuster. For example, the adjuster may include one or more variable curvature devices. Other types of spreading devices include those devices having a surface that expands as the fiber passes over the device. An example of a compacting device is a barrel cam or cylindrical cam. The width adjuster may be operatively coupled to a controller that is configured to change the orientation of the width adjuster.

In one embodiment, the band width control system includes a detection system for detecting the width of the band of fibers. The detection system may include an optical measurement system. The optical measurement system may include at least one optical sensor. The detection system may further or alternatively include a magnetic sensor, a mechanical sensor, an acoustic sensor, or

combinations of two or more types of sensors. The detection system provides closed loop feedback to the controller.

In another embodiment, an open loop system is used to control the width of the fiber band. In this embodiment, a stored calibration curve may be used by the controller to change the orientation of the width adjuster.

In one aspect of the invention, the band width controlling apparatus is used in filament winding applications. In filament winding operations, the rotating mandrel may have various cross-sectional geometric shapes, including but not limited to, a circle, an oval, an ellipse, a triangle, a rectangle, a square, a regular polygon and an irregular polygon. In addition, the rotating mandrel may have a shaped end to form a closed end composite.

The method and apparatus of the present invention are especially helpful in controlling the placement of bands made up of fibers that are difficult to maintain in a uniform spread. Other uses include the ability to control the band width so that parts having variable cross-sectional diameters can have a uniform distribution of the fibers. The apparatus increases the range of wind angle variation obtainable on parts having variable curvature on the surface of the part by impeding the spread of the fiber. This allows fiber paths having improved stability. The fibers used may include, but are not limited to, carbon fibers, silicon carbide fibers, boron fibers, glass fibers, aluminum oxide fibers, quartz fibers, basalt fibers, ceramic fibers, metal fibers, polymeric fibers and combinations thereof.

Referring to FIG. 1 , a filament delivery head 10 delivers a band of fibers 12 to a rotating mandrel 14. The filament delivery head 10 is supported by beam 16. The delivery head 10 may be rotatable about an axis perpendicular to the beam 16, and traversable along the longitudinal axis of the beam 12. Movement of the delivery head 10 is generally computer controlled. The band of fibers 12 is made up of several individual collections or bundles of filamentary fibers. The bundles are brought together to form the band. The bundles are spaced to establish a band width that is determined by the ply thickness that meets the design criteria.

To pull the fibers through the delivery head 10, the band of fibers 12 may be affixed to the rotating mandrel 14. Upon rotation of the mandrel 14, the band of fibers 12 is pulled through the delivery head 10 and placed on the mandrel 14. The rotation of the mandrel 14 controls the rate at which the band of fibers 12 is pulled through the apparatus 10. The mandrel may be rotatable about one or more axes perpendicular to the beam 16. The angle of approach of the band of fibers 12 to the axis of rotation of the mandrel 14 may range from greater than about 0 degrees to less than about 180 degrees. This may be accomplished by pivoting the delivery head 10 relative to the axis of rotation of the mandrel 14. Alternatively, the mandrel 14 may be pivoted separately or in combination with the delivery head 10. The angle of approach may be varied without pivoting the delivery head 10 or rotating the mandrel 14 by controlling the rotation rate of the mandrel 14 and the rate at which the mandrel 14 moves along the axis of rotation. As the mandrel 14 rotates, the band of fibers 12 may be layered onto the mandrel 14 in prescribed patterns with a sufficient number of layers to cover the surface of the mandrel 14. The pattern in which the band of fibers 12 is layered may vary widely and may be controlled through movement of the rotating mandrel 14, as well as by pivoting the delivery head 0 separately or in conjunction with pivoting the mandrel 14.

As illustrated in FIGS. 2 and 3, the filament delivery head 10, through which the band of fibers 12 passes, delivers the band of fibers 12 from roller 46 to mandrel 14. The band of fibers 12 is made up of a plurality of continuous fibers from a source (not shown). The bundle of fibers is drawn into the delivery head 10, over guide roll 45 and along a path through the delivery head 10. Centering ring 48 arranges the bundle of fibers drawn into the delivery head 10 into a band of fibers 12. Variable curvature rings 30 and 32 cooperate to adjust the width of the band of fibers 12. Filament delivery head 10 includes an optical measurement system 20. The optical measurement system 20 includes camera 22, light source 24, deflector 26, and prism 28 mounted to deflector 26. The optical measurement system 20 controls a pair of variable curvature rings 30 and 32. Ring adjustment drive system 34, in the illustrated embodiment, includes gear 40 coupled to ring 30, gear 42 coupled to ring 32 and gear 44, which is driven by motor 38. Belt 36 simultaneously acts on gears 40 and 42 to change the orientation of rings 30 and 32, to control the band width. Non-limiting examples of drive systems that may be used include belt drives, cam drives, and linkages.

In another embodiment, not illustrated, the width of the band of fibers is adjusted by one or more radiused bars, with the direction of motion normal to the direction of movement of the band of fibers. In another embodiment, a barrel cam may be used in combination with one or more static variable curvature rings to control the width of the band of fibers.

The optical measurement system 20 uses an electro-magnetic radiation sensor to measure incoming band width information. The sensor may contain multiple sensing units (pixels) in a linear or rectangular array. The sensor may include, for example one or more cameras, line cameras, fiber optic sensors, charge- coupled device (CCD), complementary metal-oxide semiconductors (CMOS), etc. Radiation form light source 24 is reflected off or directed from behind the fiber band 12 to prism 28 and measured by the sensor (camera 22 in FIG. 2). Measurements are converted to a digital signal and sent to an image processing or general purpose computer (not shown). The computer uses edge detection algorithms, intensity measurements and statistical averaging to determine the current fiber width.

As illustrated in FIG. 4, from the optical measurement 60 obtained by the optical measurement system 20 and the set point 62, the error is computed by the summer 64, taking the difference between the desired band width (user input or set point 62) and the measured fiber band width (actual optical measurement 60). Error, derivative and integral information is used by the controller 68, along with fiber movement data 66 obtained by rotary encoder 50, to compute the control signals sent to the band width control hardware 70. The controller 68 implements a control algorithm that can be tuned to approximate a linear proportional-integral-derivative (PID) controller if desired. The band width control hardware 70 reacts to force the fiber width closer to the set point 62 by changing the orientation of variable-curvature rings 30 and 32. Multiple variable-curvature rings may be controlled independently and multiple sensing devices may be utilized to control a single variable-curvature ring.

Referring to FIG. 5, another embodiment of a band width controlling device 80, through which the band of fibers 12 passes, includes a pair of guide rolls 82 for guiding the fibers along a path through the device 80. A spreading device 84, which includes a pair of variable curvature rings having a fixed orientation, arranges the bundle of fibers received from the guide rolls 82 into a band of fibers. A barrel cam 86 adjusts the width of the band of fibers 12.

Referring to FIG. 6, the barrel cam 86 has a channel 88 formed in the surface of the barrel cam. The width of the channel 88 is tapered along the circumference of the barrel cam, so that as the barrel cam 86 is rotated about its axis 90, the width of the band of fibers 12 may be contracted to the desired width. The orientation of the barrel cam 86 is controlled by a controller 68.

The band width controlling device 80 may include a detection system configured to detect the width of the band and output a width detection signal to a controller having a closed loop as described above and illustrated in FIG. 4.

Alternatively, the orientation of the barrel cam 86 of the band width controlling device 80 may be controlled by a controller having an open loop configuration.

Referring to FIG. 7, set point 62 is input into controller 68, optionally along with fiber movement data obtained by rotating encoder 50 to compute the control signals sent to the band width control hardware 70. The controller 68 accesses and interrogates a stored calibration curve to command the desired orientation of the barrel cam 86 to provide a specified bandwidth for the fiber band 12.

Use of the band width control apparatus described herein is not limited to filament winding. It is a versatile device that can be incorporated to work with any fiber size or type. The band width control apparatus can be modified to be used in any manufacturing application where the band width or ply thickness must be controlled or varied.

While the invention has been explained in relation to various embodiments, it is to be understood that various modifications thereof will be apparent to those skilled in the art upon reading the specification. The features of the various embodiments of the articles described herein may be combined within an article. Therefore, it is to be understood that the invention described herein is intended to cover such modifications as fall within the scope of the appended claims.

Claims

What is claimed is:

1. A device for controlling the width of a band of fibers, the band of fibers containing a plurality of continuous fiber bundles, the device comprising:

a guide roll arranged to guide a plurality of continuous fiber bundles drawn into the device from a supply thereof along a path;

a first width adjuster arranged to spread or compact the fiber bundles accepted from the guide roll;

a second width adjuster arranged along the path downstream of the first width adjuster to spread or compact the fiber bundles as a function of an orientation of the second width adjuster, the second width adjuster cooperating with the first width adjuster to form a band of fibers having the desired width and thickness; and

a controller operatively coupled to at least the second width adjuster and configured to change the orientation of the second width adjuster.

2. The device of claim 1 wherein the second width adjuster comprises a variable curvature device.

3. The device of claim 1 wherein the second width adjuster comprises a barrel cam.

4. The device of any one of claims 1-3 wherein the first width adjuster spreads or compacts the fiber bundles as a function of an orientation of the first width adjuster.

5. The device of claim 4 wherein the first width adjuster comprises a variable curvature device.

6. The device of claim 5 wherein the controller is also coupled to the first width adjuster and is configured to change the orientation of the first width adjuster.

7. The device of claim 6 wherein the orientation of each of the first and second width adjusters is changed independently of the other.

8. The device of claim 6 wherein the orientation of each of the first and second width adjusters is changed in a predetermined coordinated manner.

9. The device of any one of claims 1-8 further comprising a detection system disposed downstream of the second width adjuster and configured to detect the width of the band and output a width detection signal, wherein the controller changes the orientation of at least the second width adjuster as a function of the width detection signal output by the detection system.

10. The device of claim 9 wherein the detection system comprises at least one optical sensor.

11. The device of claim 10 wherein the optical sensor is a camera.

12. The device of claim 10 wherein the optical sensor is a fiber optic sensor.

13. The device of any one of claims 1-12 further comprising a rotary encoder disposed along the path and arranged to detect the speed of the fiber bundles drawn into the device and provide output to the controller, wherein the controller is further configured to change the orientation of at least the second width adjuster as a function of the speed detected by the encoder.

14. A delivery head assembly for a filament winding machine for applying a plurality of continuous fiber bundles in the form of a band onto a mandrel, the assembly comprising the device of any one of claims 1-13.

15. The delivery head assembly of claim 14 wherein the first width adjuster comprises a variable curvature device and the second width adjuster comprises a variable curvature device, and the controller is operatively coupled to the first and second width adjusters and configured to change the orientation of both the first and second width adjusters.

16. A method of controlling the width of a band of continuous fibers comprising: providing a plurality of continuous fibers; forming a band of fibers by compacting or spreading the plurality of continuous fibers with at least one variable curvature device, the width of the band being a function of an orientation of the at least one variable curvature device;

detecting the width of the band with a detection system;

automatically changing the orientation of the at least one variable curvature device in response to the detected width.

17. The method of claim 16 wherein the detection system comprises at least one optical sensor.

18. The method of claim 17 wherein the optical sensor is a camera.

19. The method of claim 16 wherein the detection system outputs a width detection signal to a controller that is operatively coupled to the at least one variable curvature device.