JP2001322181A - Method and device for forming almost columnar structure out of thermoplastic composite material tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device (10) for forming an almost columnar structure (14) out of a thermoplastic composite material tape (30), by welding the thermoplastic composite material tape (30) through conductive heat transfer by using at least one compression roller (40). SOLUTION: The forming device (10) includes a mandrel (20) rotated around a shaft (24) by an electric motor or another rotary type power mechanism. The rotating surface of the mandrel (20) provides a forming surface for manufacturing a columnar structure (14). The thermoplastic composite material tape (30) coming in is compressed and welded almost simultaneously by the compression roller (40) heated through the conductive heat transfer. The compression roller (40) is cleaned continuously by a burner (50), and this is executed in such a manner that an open fire (54) is directed to the roller (40) to remove contaminants and the residues of a thermoplastic composite material adhering to the compression roller (40).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method and apparatus for forming a thermoplastic ring structure, and more particularly, to a method and apparatus for cleaning during winding and forming a thermoplastic ring structure.

[0002]

BACKGROUND OF THE INVENTION In the past, most composite ring structures have been manufactured using thermoset materials. When making a ring structure using a thermoset composite, the entire ring must be cured in an autoclave at a temperature suitable to bring the material to its final solidified state. During the autoclave process, the fibers in the thermoset material tend to relax and lose alignment in the structure. It is well known in the art that fiber alignment greatly affects the strength and stiffness uniformity of a composite structure, so relaxation of these fibers is an undesirable event. As a result, the use of thermoplastic materials has been proposed as an alternative to thermoset materials.

The processing of thermoplastic composites to form ring structures requires a very different type of machine and process than is used for thermoset materials. Some distinguishing advantages can be derived from the use of thermoplastic composites to make structures such as cylindrical rings.
Specifically, as the compression and bonding of the thermoplastic composite tape occurs at the moment a new tape is added to the ring structure, such as during a winding operation, what happens to those fibers at the moment of compression and bonding Given the shape, the fibers in the thermoplastic composite matrix are locked. Locking the fiber avoids the disadvantages associated with fiber relaxation described above. Thus, locking the fibers in the composite matrix into alignment greatly increases the strength and stiffness uniformity of the resulting composite structure.

Most work in the field of fabricating ring structures from thermoplastic composites has focused on using convection heating to bring the thermoplastic composite tape to a temperature where bonding of the thermoplastic composite can occur. I've been focused. To increase the speed achievable during ring formation, convection heating was introduced several years ago into the art of thermoplastic ring formation. It is important that heat transfer via radiation and conduction cannot cause material bonding at a rate faster than 1 to 2 inches per second because sufficient thermal energy cannot be introduced into the thermoplastic composite product. Was well known in the art. This speed refers to the speed at which a new thermoplastic composite tape is added to the previous layer of the thermoplastic composite tape as the ring structure is formed. Convective heat transfer is achieved by blowing hot gas onto the thermoplastic composite tape at the point where the new tape contacts the previous layer while the winding of the ring structure is formed. The blowing of hot gas causes the thermoplastic composite to melt, so that the new and old materials combine into one solid mass.

[0005] Convective heat transfer, however, is undesirable in several respects, one of which is that it is very inefficient. Only a small portion of the heat generated is actually used to heat the thermoplastic composite tape. Most of the heat generated blows near the impinging jet and heats the machines, bearings, spindles and related structures. A further disadvantage is that convective heating is one where heating is intended, that is, between the new thermoplastic composite tape being added and the previous layer of thermoplastic composite tape wound on the ring. The inability to heat the contacts. This location is not heated because the blowing gas stagnates at an acute angle between the introduced tape and the wound ring. Stagnant convective heat has no speed and therefore cannot transfer heat.

[0006] A further problem is encountered when winding thick ring structures from thermoplastic composite tapes. To form a thick ring structure, a large amount of thermoplastic composite tape is required. This can be accomplished by lapping together several relatively short runs of thermoplastic composite tape. However, the splicing of the incoming tape leads to discontinuities in the structure and reduces the mechanical properties of the product formed. Alternatively, a single very long stretch of thermoplastic composite tape can be used to roll a thick ring structure to eliminate splices from the final product. The problem with this technique is that it is very expensive to produce thermoplastic composite tapes that are several thousand feet long and do not include splices. Several other cumbersome approaches have been devised which attempt to splice the material in place or use a type of start and stop bonding technique, all of which have resulted in undesirable results.

In situ bonding of thermoplastic composite tapes
It is an efficient technique for manufacturing flywheel ring structures. This process typically uses a heated compression roller that presses the surface of the thermoplastic composite material tape against the surface of the flywheel ring to form a fully bonded structure. One problem that arises during this process is that the coating of the thermoplastic from the thermoplastic composite tape tends to adhere to the heated compression roller.
Optimal process temperatures generally result in a rapid build-up of thermoplastic resin on the rollers. This coating causes several problems, such as: Changes in the heat transfer rate from the rollers to the ring, resulting in differences in product density, resulting in uneven pressure on the thermoplastic composite tape, and uneven surfaces with widely varying densities, This is the detachment of accumulated material on the product surface.

[0008] Previously, in situ combined cleaning devices required that the forming process be stopped in order to remove the roller with accumulated resin and manually expose the roller to the cleaning material (ie, steel wool, paper file, etc.). there were. Other prior art techniques have been proposed and implemented in an attempt to satisfactorily remove the thermoplastic resin buildup on the compression rollers. These techniques included: Physical scraping (continuous and / or manual), passive scrapers,
Spirally arranged cables and (localized and focused) infrared heating. None of these techniques turned out to be successful. The scraper heats up from contact with the compression rollers and storage material and thus wears out before long forming steps can be completed. The cured or ceramic scraper will unacceptably damage the surface of the compression roller. Finally, the focused infrared radiation cannot "see" the thermoplastic resin and therefore cannot burn off the resin from the roller surface.

[0009] Another disadvantage of the prior art bonded roller cleaning techniques is that as cylindrical products, ie, rings, are formed, they are not performed sequentially. This is important because the formation of the thermoplastic composite ring must not create any discontinuities that would occur if the process were stopped and started for an intermediate roller cleaning session.
Continuous roller cleaning is desirable. Because it can remove traces of the resin from the rollers before the resin contacts the new incoming thermoplastic composite tape at the bond. Thus, continuous cleaning helps to ensure that the pressure exerted by the compression roller is uniform over the width of the tape where the bond is occurring.

[0010] Thus, winding a ring structure using a thermoplastic material, which is relatively inexpensive, has continuously clean compression rollers, and achieves bonding of the thermoplastic composite material using conductive heat transfer. There is a continuing need for new and improved methods and apparatus for doing so.

[0011]

SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a method and apparatus for forming a substantially cylindrical structure from a tape, preferably a thermoplastic composite tape using continuously washed rollers. The method includes rotating a mandrel about an axis to provide a rotating forming surface for producing a cylindrical structure. One or more tapes are wrapped around the forming surface of the mandrel to form a generally cylindrical structure. During winding, the tape is compressed against the forming surface of the mandrel by one or more compression rollers positioned to rotate and hold the thermoplastic material against the forming surface of the mandrel. The compression roller is continuously cleaned with a burner to remove contaminants and tape residue adhered to the compression roller. Finally, almost simultaneously with the compression of the new tape against the outer layer of the generally cylindrical structure being formed, the tape is heated to bond the tape material.
Compression rollers bond the tape via conductive heat transfer.

[0012] According to another aspect of the invention, the burner is an open flame burner. The burner preferably has a controllable heating level to optimize the removal of contaminants and residues. The burner heats the compression roller sufficiently so that the compression roller bonds the tape material via conductive heat transfer.
Continuous cleaning of the compression roller by the burner removes substantially all contaminants and components of the resin from the tape that have adhered to the compression roller. In addition, thermoplastic columnar structures are made using a fully automated process. The continuous cleaning of the compression roller by the burner eliminates the need for intermittent manual cleaning of the compression roller,
Enable full automation.

According to another aspect of the invention, the mandrel is rotated about an axis to provide a rotating forming surface for producing a cylindrical structure. As the mandrel is rotated, tape is wrapped around the forming surface of the mandrel to provide a cylindrical structure. The tape material is compressed against the forming surface of the mandrel by a compression roller positioned to rotate and hold the tape against the rotating forming surface of the mandrel. The compression roller is continuously cleaned with a burner to remove resin contaminants and components from the tape material adhered to the compression roller.

In accordance with a further aspect of the invention, the compression roller is heated by either a single burner or a burner associated with electrical heating. Preferably, the burner is an open flame burner with a controllable heating level. The burner heats the compression roller sufficiently so that the roller bonds the tape material via conductive heat transfer. Continuous cleaning of the compression roller by the burner removes substantially all contaminants and components of resin from the tape material that adhere to the compression roller.

According to yet another aspect of the method of the present invention, the tape is formed from a thermoplastic composite.

As will be readily appreciated from the foregoing summary,
A continuously cleaning compression roller ring winder device made in accordance with the present invention has several advantages over the prior art methods and devices described above. The present invention preferably uses conductive heat transfer to compress and bond the formed ring structures together so that the fibers contained in the tape material wrapped around the mandrel are locked in alignment and formed. Enhance the mechanical properties of the structure. The wrapping of the tape material around the mandrel-forming surface and the compression / bonding of the plurality of tapes by heated compression rollers allows for the production of cylindrical structures without lap splices. Finally, by using continuous cleaning of the compression rollers, the following are minimized: (2) uneven pressure on the tape and (3) uneven surfaces with widely varying densities resulting in differences in density of the product, resulting in (1) changes in the heat transfer rate from the roller to the ring. Scatter of the accumulated material on the surface of the product, which results in The end result is
Excellent part quality overall.

The foregoing aspects and many of the attendant advantages of this invention will be more readily appreciated as they become better understood by reference to the following detailed description when taken in conjunction with the drawings. Would.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a preferred embodiment of a roller ring winder 10 made in accordance with the present invention, which includes one or more compression rollers 4.
0 to form a generally cylindrical structure 14 from one or more tapes 30 formed from a thermoplastic composite, which couples the thermoplastic composite via conductive heat transfer. . Roller ring winder 1 shown
O includes a mandrel 20 that is rotated about axis 24 by an electric motor or other rotary power supply (not shown). The outer circumference of the mandrel 20 provides a rotating forming surface for use in manufacturing the cylindrical laminate structure 14.
As the mandrel is rotated, one or more thermoplastic composite tapes are wrapped around the mandrel. Each of the incoming thermoplastic composite tapes 30 is compressed and bonded substantially simultaneously by its respective heated compression rollers 40 via conductive heat transfer as the tape is wrapped. For ease of illustration, only one compression roller is shown in FIG. The compression roller is supported by a mechanism that presses the compression roller against the outer layer of tape wrapped around the mandrel 20. A support mechanism known in the art is schematically illustrated as a spring 42 that holds a shaft 44 on which the compression roller 40 is mounted. The support mechanism provides a continuous compression pressure on the outer tape wrap. In accordance with the present invention, the compression roller 40 is continuously cleaned with a burner 50, which directs a flame 54 toward the surface of the roller 40 remote from the compression point, from the thermoplastic composite tape 30 adhered to the compression roller 40. Removes resin contaminants and other components.

The rotating shaft 24 of the driven mandrel 20
Preferably lies in a substantially horizontal plane.
This direction of rotation is preferred because the thermoplastic composite material tape 30 is heated to the bonding temperature by the compression roller 40, thus bringing the resin contained in the thermoplastic composite material tape into a viscous, semi-molten state. If the rotating shaft 24 of the driven mandrel 20 is oriented in a substantially vertical plane, the viscous molten resin flows axially towards the lower end of the formed columnar structure due to gravity. Will tend to produce a distorted end product.

Referring again to FIG. 1, the incoming thermoplastic composite tape 30 is preferably distributed from a material supply reel (not shown but well known in the art). Further, it is advantageous that the incoming tape 30 is in tension as the tape 30 approaches the compression roller 40 during a suitable compression and bonding process. Tension reduces defects in the final product, such as wrinkles and other compression defects. To provide tension into the thermoplastic composite tape 30,
Preferably, a tension roller (not shown but well known in the art) is used. The tension roller inhibits the tape 30 at a point after the tape leaves the supply reel, but before the tape 30 reaches the compression roller 40. One known friction deterrent technique involves guiding a thermoplastic composite tape 30 between a pair of juxtaposed tension rollers.

The thermoplastic composite tape 30 is compressed against the forming surface of the mandrel 20 by a heated compression roller 40, which, as shown in FIG. 1 and described above, rests on the surface of the mandrel 20. The thermoplastic composite tape 30 is positioned to rotate and hold against the generally cylindrical structure 14 to be formed. Almost simultaneously with the application and compression of the incoming thermoplastic composite tape 30 to the formed cylindrical laminate structure 14, the thermoplastic composite tape 30 conducts by contact with the heated compression roller 40. Through the heating to a temperature (above the glass transition temperature of the material) sufficient to bond the thermoplastic composite material forming the tape 30.

The present invention relates to a thermoplastic composite tape 30.
Although discussed primarily in connection with the formation of a generally cylindrical structure 14 formed from the same, the invention may also be used to create structures using other types of materials. For example, using a burner 50 with an open flame 54, a thermosetting material compression process may also remove residue and / or contaminants from the compression roller 40. More specifically, in accordance with the present invention, the compression process of metals, alloys, hybrids and other compounds using compression rollers may also use burners 50 to remove residues and contaminants from compression rollers 40.

As shown in FIG. 1, rollers 40 hold incoming thermoplastic composite material tape 30 by pressing the incoming tape against the circumferential forming surface of driven mandrel 20. It compresses into the generally cylindrical structure 14 that has been formed. As previously discussed, the compression roller 40 is heated, and the roller heats the thermoplastic composite tape 30 via conductive contact with the tape 30. This heating is sufficient to bond the resin contained in the tape at about the same time as the compression of the incoming tape against the outer wrap over the structure to be formed. Previously used heated compression rollers use mechanisms such as internal electrical coils to create the required bonding temperature (generally above the glass transition temperature of the thermoplastic). As noted above, preferably in accordance with the present invention, burner 50 sufficiently heats compression roller 40 during its successive cleaning cycles, eliminating the need for an additional heating mechanism. In this manner, the present invention not only reduces the cost and complexity of the device 10, but also increases the efficiency of the production process. Alternative embodiments of the present invention (or for certain types of materials with high bonding temperatures), together with the heating of the compression roller 40 derived from the burner 50, are shown schematically with internal electrical coils or (coils 58). ) Other heating mechanisms may be used. An electric coil can be used to preheat the compression roller during startup. Even in these embodiments, burner 50 provides at least some of the heat required to heat compression roller 40 to the appropriate temperature. Thus, even in these embodiments, the present invention reduces the required energy and results in substantial cost savings.

In another alternative embodiment of the present invention, the compression roller 40 is provided primarily for (or only for) compression of the thermoplastic composite tape 30 against the outer wrap of the formed cylindrical structure 14. ) And not for coupling via conductive heat transfer. In such embodiments of the present invention, other methods for heating the thermoplastic composite tape 30 to the bonding temperature (such as convection, infrared heating, etc.) are used. Because compression roller 40 is still susceptible to resin and other residues from thermoplastic composite tape 30 and other contaminants, such an embodiment uses the burner 50 of the present invention to reduce the pressure of the compression roller. Provides the necessary continuous cleaning. Thus, regardless of the heat transfer method used to heat the thermoplastic composite tape 30 to the bonding temperature, the compression roller 40 with the burner 50 of the present invention.
Continuous cleaning is functional and advantageous.

The burner 50 made in accordance with the present invention preferably has the opportunity for the roller 40 to make a full revolution, compressing contaminants and components to the newly forming surface of the generally cylindrical structure 14 being made. Prior to removing substantially all of the thermoplastic material residue and other contaminants that adhere to the compression roller 40. Preferably, the burner 50 uses an open flame. Also, preferably, the level or speed of the heat or open flame 54 generated by the burner is controlled by a suitable controller 60.
Can be controlled by Control of the burner 50 allows the burner temperature level and heat rate to be set to the levels required to achieve complete removal of different types of material residues and other contaminants. Thus, the present invention allows the required open flame 54 and heat levels to be achieved with burner 50 and is also cost effective in situations where lower levels of heat or flame are tolerated.

A further advantage is that the continuous cleaning compression roller ring winder 10 formed in accordance with the present invention allows for the full automation of the formation of the generally cylindrical structure 14. The present invention provides additional cost savings for manual shaving by eliminating the need for a full-time employee to scrape off contaminants and residue from the compression roller 40 on a dedicated basis.

The invention has been described with reference to a preferred method and a preferred apparatus. After reading the foregoing specification, one skilled in the art will be able to make various other changes, modifications and alternatives, or equivalents thereof, without departing from the disclosed concepts. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.

[Brief description of the drawings]

FIG. 1 is a side view of a composite ring winder formed in accordance with the present invention.

[Explanation of symbols]

14 cylinder structure, 20 mandrel, 40 compression roller, 50 burner, 60 controller

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Claims (20)

[Claims] 1. A method of forming a substantially cylindrical structure from a thermoplastic composite tape, comprising: (a) rotating a mandrel about an axis to provide a rotating forming surface; Wrapping at least one tape of thermoplastic composite material around a forming surface of the mandrel to form a generally cylindrical structure; and (c) rotating and pressing the thermoplastic composite material against the forming surface of the mandrel. Compressing at least one tape of thermoplastic composite against the forming surface of the mandrel with at least one compression roller positioned as follows: (d) continuously cleaning the at least one compression roller with a burner. To remove resin contaminants and components from the thermoplastic composite adhered to at least one compression roller. (E) bonding at least one thermoplastic composite tape by heating at least one thermoplastic composite tape substantially simultaneously with the compression of the thermoplastic composite into the substantially cylindrical structure being formed. And the step of causing
Method. 2. A method of forming a generally cylindrical structure, comprising: (a) rotating a mandrel about a horizontal axis to provide a rotating forming surface; and (b) forming a mandrel. Wrapping the material around the surface to form a cylindrical structure; and (c) at least one compression roller positioned to rotate and hold the material against the forming surface of the mandrel; Compressing the material; and (d) continuously cleaning at least one compression roller with a burner to remove contaminants and residues from the material adhered to the compression roller. 3. The method according to claim 1, wherein the burner comprises an open flame burner. 4. The method according to claim 1, wherein the burner has a controllable heating level. 5. The method of claim 1, wherein the burner heats at least one compression roller sufficiently that the at least one compression roller bonds the thermoplastic composite via conductive heat transfer. 6. The continuous cleaning of at least one compression roller by a burner removes substantially all contaminants and components of resin from the thermoplastic composite that adhere to the at least one compression roller. 3. The method according to 1 or 2. 7. The method of claim 2, wherein the material is a thermoplastic composite. 8. The method of claim 2, wherein at least one compression roller is heated. 9. The method according to claim 8, wherein the at least one compression roller is heated only by a burner. 10. The method of claim 8, wherein at least one compression roller is electrically heated. 11. An apparatus for forming a substantially cylindrical structure from a thermoplastic composite tape, comprising: (a) a mandrel having a rotating shaft and a forming surface for receiving a thermoplastic composite tape; The thermoplastic composite tape is wrapped around the forming surface of the mandrel to form a generally cylindrical structure, and (b) rotating and adjustably compressing the thermoplastic composite tape against the forming surface of the mandrel. At least one compression roller coupled to the thermoplastic composite tape at substantially the point of contact between the thermoplastic composite material and the compression roller, thereby forming a substantially cylindrical structure. Combine and compress
Further, (c) an apparatus including a burner, wherein the burner continuously cleans at least one compression roller by removing contaminants and residues from the thermoplastic composite adhered to the compression roller. 12. An apparatus for forming a generally cylindrical structure, comprising: (a) a rotating surface and a forming surface for receiving material wound around a forming surface of a mandrel to form a cylindrical structure; And (b) at least one compression roller positioned to rotate and adjustably compress the material against the forming surface of the mandrel; and (c) a burner, the burner comprising: An apparatus for continuously cleaning at least one compression roller by removing contaminants and residues from material adhered to the compression roller. 13. The burner of claim 1, wherein the burner comprises an open flame burner.
13. The device according to 1 or 12. 14. The apparatus according to claim 11, further comprising a controller for controlling a burner heating level. 15. The apparatus of claim 11, wherein the burner heats at least one compression roller sufficiently that the at least one compression roller bonds the thermoplastic composite tape via conductive heat transfer. 16. The continuous cleaning of at least one compression roller by the burner removes substantially all contaminants and components of resin from the thermoplastic composite tape adhered to the at least one compression roller. 13. The device according to 11 or 12. 17. The device according to claim 12, wherein the material is a thermoplastic composite. 18. The method of claim 17, wherein the compression roller is heated.
An apparatus according to claim 1. 19. The apparatus according to claim 18, wherein the compression roller is heated only by a burner. 20. The apparatus of claim 18, wherein the compression roller is electrically heated.