CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and any benefit of European Patent

Application No. 18306130.8, filed August 22, 2018, the entire content of which is incorporated herein by reference.

FIELD

[0002] The present application relates generally to apparatuses and processes for manufacturing reinforcing fibers, and in particular, for cutting mineral and carbon fibers by way of a vibrating cutting device.

BACKGROUND

[0003] Cutting or“chopping” fibers or bundles of fibers on a continuous

manufacturing line or in an offline process is known to those skilled in the art. Fibers may be cut across the direction of travel, i.e., transversely, or be cut along the direction of travel, i.e., longitudinally. Transverse and longitudinal cutting of the fibers may be performed by using a cutting assembly including a cutting device and an anvil. The cutting assemblies draw several continuous fibers at a high rate of about one or more tens of meters per second. Fibers are cut transversely into fragments of a predetermined length or longitudinally into bundles with a predetermined width.

SUMMARY

[0004] Exemplary embodiments of cutting systems for fibers are disclosed herein.

[0005] In one exemplary embodiment, an apparatus for manufacturing cut fibers comprises a cutting device (220, 340) for cutting fibers (202, 302) drawn from a supply of fibers (210, 310) into cut fibers (204, 304); and characterized in that the cutting device comprises: an anvil (222, 342); a cutting implement (226, 346) having a plurality of cutting edges (227, 347) for pressing the fibers against the anvil; and an ultrasonic vibration source (228, 240, 348, 350) for vibrating the cutting implement to cut the fibers, wherein the ultrasonic vibration source has a frequency of about 20 kHz to about 40 kHz, wherein the ultrasonic vibration source has an amplitude of about 10 micrometers to about 30

micrometers, and wherein the cutting device cuts the fibers transversely, across a direction of travel (201, 301). [0006] In some exemplary embodiments, the apparatus further comprises a coating applied to the fibers, wherein the vibration of the cutting implement heats the coating to bind the cut fibers together.

[0007] In some exemplary embodiments, the cutting implement is a cutting wheel

(226, 346) and the ultrasonic vibration source is arranged on an axis of rotation (241, 351) of the cutting wheel.

[0008] In some exemplary embodiments, an outer diameter of the cutting wheel is about 90 millimeters to about 310 millimeters.

[0009] In some exemplary embodiments, the cutting edges are spaced apart from one another by a distance of about 3 millimeters to about 50 millimeters.

[0010] In some exemplary embodiments, the fibers comprise glass fibers.

[0011] In some exemplary embodiments, the fibers comprise carbon fibers.

[0012] In some exemplary embodiments, the fibers have a diameter of about 10 micrometers to about 14 micrometers.

[0013] In some exemplary embodiments, the fibers are cut by the cutting device while moving at a linear speed of about 900 meters per minute to about 1,800 meters per minute.

[0014] In one exemplary embodiment, a process for manufacturing cut fibers comprises cutting fibers (202, 302) into cut fibers (204, 304); and collecting the cut fibers with a collecting device (230, 330); the improvement characterized in that the fibers are cut with a cutting device (220, 340) that comprises: an anvil (222, 342); a cutting implement (226, 346) having a plurality of cutting edges (227, 347) for pressing the fibers against the anvil; and an ultrasonic vibration source (228, 240, 348, 350) for vibrating the cutting implement to cut the fibers, wherein the ultrasonic vibration source has a frequency of about 20 kHz to about 40 kHz, wherein the ultrasonic vibration source has an amplitude of about 10 micrometers to about 30 micrometers, and wherein the cutting device cuts the fibers transversely, across a direction of travel (201, 301).

[0015] In some exemplary embodiments, the cutting implement is a cutting wheel

(226, 346).

[0016] In some exemplary embodiments, the ultrasonic vibration source (240, 350) is arranged on an axis of rotation (241, 351) of the cutting wheel.

[0017] In some exemplary embodiments, the process further comprises binding the cut fibers together through heating a coating applied to the fibers with the cutting implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] These and other features and advantages of the present invention will become better understood with regard to the following description and accompanying drawings in which:

[0019] Figure 1 shows fibers being cut by a prior art cutting device;

[0020] Figures 2-5 show fibers being cut by an exemplary cutting device;

[0021] Figure 6 shows an exemplary manufacturing line for manufacturing cut fibers;

[0022] Figure 7 shows an exemplary manufacturing line for manufacturing cut fibers;

[0023] Figure 8 shows an exemplary manufacturing line for manufacturing cut fibers;

[0024] Figure 9 is a perspective view of the cutting wheel of Figure 6;

[0025] Figure 10 is a perspective view of the anvil of Figure 7 and the cutting wheel of Figure 8;

[0026] Figure 11 is a perspective view of the cutting wheel of Figure 6 attached to an ultrasonic vibration source; and

[0027] Figure 12 is a perspective view of the cutting wheel of Figure 8 attached to an ultrasonic vibration source.

DETAILED DESCRIPTION

[0028] Prior to discussing the various embodiments, a review of the definitions of some exemplary terms used throughout the disclosure is appropriate. Both singular and plural forms of all terms fall within each meaning.

[0029] As described herein, when one or more components are described as being connected, joined, affixed, coupled, attached, or otherwise interconnected, such

interconnection may be direct as between the components or may be indirect such as through the use of one or more intermediary components. Also, as described herein, reference to a “member,”“component,” or“portion” shall not be limited to a single structural member, component, or element but can include an assembly of components, members, or elements. Also, as described herein, the terms“substantially” and“about” are defined as at least close to (and includes) a given value or state (preferably within 10% thereof, more preferably within 1% thereof, and most preferably within 0.1% thereof). [0030] Reinforcing fibers, such as mineral fibers (e.g., glass fibers) and carbon fibers, may be manufactured and processed as long bundles or ribbons of fibers on a continuous manufacturing line. The ribbons of fibers may be collected onto a spool of material to be transported to another location for further processing (i.e., offline processing) or may be processed on the same line in which the fibers were made (i.e., inline processing). The bundles of fibers may be cut longitudinally, i.e., along the length of the bundle of fibers, to create a narrower bundle having the same length. The bundles of fibers may cut transversely, i.e., across the bundle of fibers, to form many shorter fibers. In either case— longitudinal or transverse cutting— the cutting process performed continuously without removing the fibers from the manufacturing line. The fibers may travel down the manufacturing line at a high linear speed of about one or more tens of meters per second. Thus, suitable cutting devices for cutting the fibers must be capable of processing bundles of fibers moving at these speeds. Ultrasonic vibration can be used to enable cutting devices to process bundles of fibers at high linear speeds. Ultrasonic vibrations are transmitted to a cutting implement of the cutting device from an ultrasonic vibration source. Exemplary ultrasonic vibration sources generate vibrations at frequencies ranging in the tens of kilohertz (kHz) with an amplitude up to tens of micrometers (pm).

[0031] Referring now to Figure 1, a prior art cutting device 10 is shown cutting through a bundle of fibers 20. The cutting device 10 includes a cutter 12 that is pressed through the fibers 20 in the cutting direction 14 to cut the fibers 20. As the cutter 12 engages the fibers 20, each fiber breaks at a cut location 16. To ensure a successful cut, sufficient force must be applied to the cutter 12 to break through each individual strand or fiber 22 in the bundle of fibers 20.

[0032] Stress is experienced in the fibers 22 at a distance from the cut location 16 as the fibers 22 are pressed together by the cutter 12. The additional stress experienced by the fibers 22 can cause secondary fractures 18 to occur, thereby generating debris fibers 24 that are shorter than the desired cut fiber length. A rough, cut surface is formed as the debris fibers 24 fall away from the bundle of fibers 20. The rough, cut surfaces cause the cutter 12 to wear down over time until maintenance is required to replace or repair the cutter 12. When the bundle of fibers 20 is cut longitudinally, the debris fibers 24 may gather together and travel with the cut fibers that are being moved through the manufacturing line at high speeds.

[0033] Referring now to Figures 2-5, an exemplary cutting device 100 is shown cutting through a bundle of fibers 102. The cutting device 100 includes a cutting implement 110 that is vibrated by an ultrasonic vibration source (not shown) to cut the fibers 104 at a cut location 106. The ultrasonic vibration source can be an ultrasonic oscillator, i.e., a device capable of oscillating the cutting implement 110 at a frequency of about 20 kHz to about 40 kHz with an amplitude of about 10 pm to about 30 pm. In some embodiments, the frequency and amplitude of the vibration source are both adjustable.

[0034] The ultrasonic vibration source causes the cutting implement 110 to move back and forth between a cutting direction 112 (Fig. 2) and a retreat direction 114 (Fig. 3).

The movement of the cutting implement 110 shown in Figures 2-5 is exaggerated to better illustrate the movement of the cutting implement 110 toward and away from the bundle of fibers 102. As the cutting implement 110 is advanced through the bundle of fibers 102, the cutting implement 110 rapidly cycles between impacting and retreating from the fibers 104.

[0035] Because of the vibratory movement of the cutting implement 110, the cutting implement 110 breaks through fewer fibers 104 with each impact and less force is needed to cut through the entire bundle of fibers 102. Thus, secondary fractures are reduced or eliminated when the fibers 104 are cut with the vibrating cutting implement 110. As a result, the cutting implement 110 experiences less wear and lasts longer between maintenance cycles. Similarly, the anvil (not shown) that supports the bundle of fibers 102 during cutting is exposed to less stress during cutting so that wear on the anvil is reduced.

[0036] The oscillating movement of the cutting implement 110 during cutting of the fibers 104 generates heat from friction that can melt or fuse coatings applied to the fibers, e.g., sizing, or the fibers themselves to bind the fibers 104 together. Binding the fibers 104 together at the same time as the fibers 104 are cut or broken produces a relatively smooth cut edge of the bundle of fibers 102.

[0037] The principle of operation of the cutting device 100 is shown and described in the abstract in Figures 2-5 and related description above. Specific embodiments of manufacturing lines are described below that employ cutting devices applying the principles described with respect the cutting device 100, above. Thus, the embodiments described below may include any of the features and capabilities of the cutting device 100 described above.

[0038] Referring now to Figure 6, a schematic view of a manufacturing line 200 for producing transversely cut or chopped reinforcing fibers is shown. The manufacturing line 200 includes a supply 210 for supplying fibers 202 to a cutting device 220. Cut fibers 204 are collected in a collecting device 230 after being cut by the cutting device 220. The collecting device 230 includes a funnel 232 that channels the cut fibers 204 to a storage container or to a conveyor of another manufacturing line (not shown) for further processing. The

manufacturing line 200 may optionally include one or more guiding devices 212 for aligning the fibers 202 prior to processing by the cutting device 220. The manufacturing line 200 may also include a fiber production apparatus (not shown) for producing the fibers 202 directly from raw material, rather than a supply 210 of previously manufactured fibers.

[0039] Fibers 202 are continuously supplied from the supply 210 and are moved in a direction of travel 201 through the manufacturing line 200. The supply 210 may be a roll of reinforcing fibers or may be the end of another manufacturing line (not shown) that forms fibers 202 from raw materials, such as glass, carbon, or any other suitable material. In some embodiments, the fibers are glass fibers formed with a diameter of about 10 pm to about 17 pm.

[0040] The fibers 202 are cut transversely by the cutting device 220 into shorter cut fibers 204 having a predetermined length. The fibers 202 are cut between an anvil wheel 222 and a cutter 224. The cutter 224 includes a cutting implement or wheel 226 and an ultrasonic vibration source 228. As can be seen in Figure 9, the peripheral surface of the cutting wheel 226 includes a plurality of cutting edges 227. The cutting wheel 226 presses the uncut fibers 202 against the anvil wheel 222 so that the cutting edges 227 engage and chop the fibers 202 into shorter, cut fibers 204. A pressing wheel 221 may optionally be included to retain the uncut fibers 202 against the anvil wheel 222 prior to cutting.

[0041] The cutting edges 227 of the cutting wheel 226 are vibrated by the ultrasonic vibration source 228 so that the fibers 202 are cut as described above with regards to Figures 2-5. Because less force is needed to cut through the fibers 202 when the cutting edges 227 are vibrated ultrasonically, the cutting wheel 226 and anvil wheel 222 require less maintenance than a non-vibrating cutter.

[0042] The cutting wheel 226 and anvil wheel 222 can be made from any suitable material, such as, for example, tungsten carbide, polycrystalline diamond, aluminum alloys, tool steel, and titanium alloys. The cutting wheel 226 can optionally be provided with a surface treatment to increase hardness and wear resistance. The anvil wheel 222 can include a coating formed from a smooth elastomeric material, such as polyurethane, to improve the wear resistance of the anvil wheel 222. The coating may be about 1 millimeter to about 5 millimeters thick and have a hardness of about 85 ShA, about 95 ShA, or about 67 ShD. [0043] The cutting wheel 226 has an outer diameter of about 90 millimeters to about

310 millimeters, or about 135 millimeters. The cutting edges 227 are spaced about 3 millimeters apart, about 4.5 millimeters apart, about 6 millimeters apart, about 9 millimeters apart, about 12 millimeters apart, about 24 millimeters apart, or about 50 millimeters apart. The cutting wheel 226 includes as few as five cutting edges 227 and as many as ninety-five cutting edges 227. The cutting wheel 226 has a width of about 40 millimeters to about 50 millimeters, or about 45 millimeters. In some embodiments, the cutting device 220 includes two or more cutting wheels 226 axially aligned to create a cutting area width of about 80 millimeters to 100 millimeters, or about 90 millimeters. In some embodiments, the cutting device 220 includes two or more cutting wheels 226 that are not axially aligned.

[0044] Referring now to Figures 7-8, a schematic view of a manufacturing line 300 for producing longitudinally cut reinforcing fibers is shown. The manufacturing line 300 includes a supply 310 for supplying a bundle of fibers 302 to a cutting device 320, 340. Cut fibers 304 are collected in a collecting device 330 after being cut by the cutting device 320, 340. The collecting device 330 includes spools 332 that wind up the cut fibers 304. As is shown in Figures 7-8, the cut fibers 304 can be gathered on separate spools 332. In certain embodiments, the cut fibers 304 are collected on a single spool. The manufacturing line 300 may optionally include one or more guiding devices 312 for aligning the bundle of fibers 302 prior to processing by the cutting device 320, 340.

[0045] Bundles of fibers 302 are continuously supplied from the supply 310 and are moved in a direction of travel 301 through the manufacturing line 300. The supply 310 may be a roll of reinforcing fibers or may be the end of another manufacturing line (not shown) that forms bundles of fibers 302 from raw materials, such as glass, carbon, or any other suitable material. In some embodiments, the fibers are glass fibers formed with a diameter of about 10 pm to about 17 pm.

[0046] The bundle of fibers 302 is cut longitudinally by the cutting device 320, 340 into narrower ribbons of cut fibers 304 having a predetermined width. When cutting the bundle of fibers 302 longitudinally, individual fibers or filaments of the bundle of fibers 302 may not be broken but merely spread apart by the cutting device 320, 340 to form the narrower bundles or ribbons of cut fibers 304. Some individual fibers are cut, however, because the individual fibers are not perfectly aligned in a longitudinal direction, i.e., with the direction of travel 301. [0047] Referring now to Figure 7, the fibers 302 are cut between an anvil wheel 322 and a cutter 324. The cutter 324 includes a non-rotating or static cutting implement 326 and an ultrasonic vibration source 328. As can be seen in Figure 10, the peripheral surface of the anvil wheel 322 includes a plurality of cutting edges 323. The cutter 324 presses the uncut fibers 302 against the anvil wheel 322 so that the cutting edges 323 engage and cut or split the bundle of fibers 302 into narrower bundles of fibers 304.

[0048] The cutting implement 326 is vibrated by the ultrasonic vibration source 328 so that the fibers 302 are cut in an opposite manner as is described above with regards to Figures 2-5. That is, the fibers 302 are moved toward cutting edges 323 of the anvil wheel 322 rather than moving the cutting surface 323 toward the fibers 302. Because less force is needed to cut through the fibers 302 when the cutting implement 326 is vibrated

ultrasonically, the anvil wheel 322 and cutting implement 326 require less maintenance than a non-vibrating cutter.

[0049] The cutting implement 326 and anvil wheel 322 can be made from any suitable material, such as, for example, tungsten carbide, polycrystalline diamond, aluminum alloys, tool steel, and titanium alloys. The anvil wheel 322 can optionally be provided with a surface treatment to increase hardness and wear resistance. The cutting implement 326 can include a coating formed from a smooth elastomeric material, such as polyurethane, to improve the wear resistance of the cutting implement 326. The coating may be about 1 millimeter to about 5 millimeters thick and have a hardness of about 85 ShA, about 95 ShA, or about 67 ShD.

[0050] The anvil wheel 322 has an outer diameter of about 90 millimeters to about

310 millimeters, or about 135 millimeters. The cutting edges 323 are spaced about 3 millimeters apart, about 4.5 millimeters apart, about 6 millimeters apart, about 9 millimeters apart, about 12 millimeters apart, or about 24 millimeters apart. The anvil wheel 322 includes as few as one cutting edge 323 and as many as sixteen cutting edges 323. The anvil wheel 322 has a width of about 40 millimeters to about 50 millimeters, or about 45 millimeters. In some embodiments, the cutting device 320 includes two or more anvil wheels 322 axially aligned to create a cutting area width of about 80 millimeters to 100 millimeters, or about 90 millimeters. In some embodiments, the cutting device 320 includes two or more anvil wheels 322 that are not axially aligned. [0051] Referring now to Figure 8, the fibers 302 are cut between a non-rotating or static anvil 342 and a cutter 344. The cutter 344 includes a cutting implement or wheel 346 and an ultrasonic vibration source 348. As can be seen in Figure 10, the peripheral surface of the cutting wheel 346 includes a plurality of cutting edges 347. The cutting wheel 346 has the same structure as the anvil wheel 322. However, the cutting wheel 346 is connected to the vibration source 348 while the anvil wheel 322 is not. The cutter 344 presses the uncut fibers 302 against the anvil 342 so that the cutting edges 347 engage and cut or split the bundle of fibers 302 into narrower bundles of fibers 304. In some embodiments, the anvil 342 is an anvil wheel like the anvil wheel 222 described above and shown in Figure 6.

[0052] The cutting edges 347 of the cutting wheel 346 are vibrated by the ultrasonic vibration source 348 so that the fibers 302 are cut as described above with regards to Figures 2-5. Because less force is needed to cut through the fibers 302 when the cutting edges 347 are vibrated ultrasonically, the cutting wheel 346 and anvil 342 require less maintenance than a non-vibrating cutter.

[0053] The cutting wheel 346 and anvil 342 can be made from any suitable material, such as, for example, tungsten carbide, polycrystalline diamond, aluminum alloys, tool steel, and titanium alloys. The cutting wheel 346 can optionally be provided with a surface treatment to increase hardness and wear resistance. The anvil 342 can include a coating formed from a smooth elastomeric material, such as polyurethane, to improve the wear resistance of the anvil 342. The coating may be about 1 millimeter to about 5 millimeters thick and have a hardness of about 85 ShA, about 95 ShA, or about 67 ShD.

[0054] The cutting wheel 346 has an outer diameter of about 90 millimeters to about

310 millimeters, or about 135 millimeters. The cutting edges 347 are spaced about 3 millimeters apart, about 4.5 millimeters apart, about 6 millimeters apart, about 9 millimeters apart, about 12 millimeters apart, about 24 millimeters apart, or about 50 millimeters apart. The cutting wheel 346 includes as few as five cutting edges 347 and as many as ninety-five cutting edges 347. The cutting wheel 346 has a width of about 40 millimeters to about 50 millimeters, or about 45 millimeters. In some embodiments, the cutting device 340 includes two or more cutting wheels 346 axially aligned to create a cutting area width of about 80 millimeters to 100 millimeters, or about 90 millimeters. In some embodiments, the cutting device 340 includes two or more cutting wheels 346 that are not axially aligned. [0055] Referring now to Figures 11 and 12, ultrasonic vibration sources 240, 350 are shown attached to respective exemplary cutting wheels 226, 346 described above. The vibration sources 240, 350 include a converter 242, 352 that generates the vibrations and a shaft 244, 354 that transmits the vibrations to the cutting wheel 226, 346. The vibrations are transmitted along an axis of rotation 241, 351 of the cutting wheel 226, 346. The vibrations cause the cutting wheel 226, 346 to expand and contract axially. Because the mass of the cutting wheel 226, 346 is not changed, the cutting wheel 226, 346 expands radially in response to the axial compression, and retracts radially in response to the axial expansion. Thus, the vibrations are transmitted radially throughout the entire cutting wheel 226, 346 and to each cutting edge 227, 347, simultaneously.

[0056] A process for manufacturing cut reinforcing fibers includes steps of supplying fibers from a supply of fibers to a manufacturing line that moves the fibers in a direction of travel, cutting the fibers drawn from the supply with a cutting device, and collecting the fibers with a collecting device. The cutting device includes an anvil, a cutting implement for pressing the fibers against the anvil, and an ultrasonic vibration source for vibrating the cutting implement to cut the fibers.

[0057] The cutting device used in the process may be any of the cutting devices 220,

320, 340 including ultrasonic vibration sources 228, 240, 328, 348, 350 described above. In particular, the cutting implement of the cutting device may be a rotating cutting wheel or may be a static cutting implement. Similarly, the anvil can be a rotating anvil wheel or may be a static member. The cutting device may cut the fibers transversely, across the direction of travel, or may cut the fibers longitudinally, along the direction of travel.

[0058] The cutting devices 220, 320, 340 described above enable cutting of reinforcing fibers at linear speeds of about 900 meters per minute to about 1,800 meters per minute through the cutting device 220, 320, 340. The capacity of the cutting devices 220,

320, 340 may be increased by increasing the width of the components of the cutter 224, 324, 344 and/or by operating a plurality of cutters 224, 324, 344 in parallel.

[0059] While various inventive aspects, concepts, and features of the disclosures may be described and illustrated herein as embodied in combination in the exemplary

embodiments, these various aspects, concepts and features may be used in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the present application. Still further, while various alternative embodiments as to the various aspects, concepts and features of the disclosures-such as alternative materials, structures, configurations, methods, devices and components, alternatives as to form, fit and function, and so on-may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adopt one or more of the inventive aspects, concepts or features into additional embodiments and uses within the scope of the present application even if such embodiments are not expressly disclosed herein. Additionally, even though some features, concepts or aspects of the disclosures may be described herein as being a preferred arrangement or method, such description is not intended to suggest that such feature is required or necessary unless expressly so stated. Still further, exemplary or representative values and ranges may be included to assist in understanding the present application, however, such values and ranges are not to be construed in a limiting sense and are intended to be critical values or ranges only if so expressly stated. Moreover, while various aspects, features and concepts may be expressly identified herein as being inventive or forming part of a disclosure, such

identification is not intended to be exclusive, but rather there may be inventive aspects, concepts, and features that are fully described herein without being expressly identified as such or as part of a specific disclosure, the disclosures instead being set forth in the appended claims. Descriptions of exemplary methods or processes are not limited to inclusion of all steps as being required in all cases, nor is the order that the steps are presented to be construed as required or necessary unless expressly so stated. The words used in the claims have their full ordinary meanings and are not limited in any way by the description of the embodiments in the specification.