Patent Application
20240117527
The information provided in this section is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
The present disclosure relates to systems and methods for processing bast fibers, and more particularly to systems and methods for processing bast fibers including rollers.
Natural fibers include bast, leaf, seed, wood, and grass stem. Bast fibers include flax, hemp, jute, ramie and kenaf. To increase sustainability and renewability, bast fibers may be used instead of other types of reinforcing fibers such as carbon fibers when manufacturing structural and semi-structural components.
A method for processing bast fibers includes orienting the bast fibers substantially parallel to one another; and feeding the bast fibers into a roller system to at least one of bend and break stems of the bast fibers. The roller system includes a first roller including a first plurality of teeth and a second roller including a second plurality of teeth having a span distance. The first roller and the second roller are arranged such that each of the first plurality of teeth passes between adjacent pairs of the second plurality of teeth. The first plurality of teeth of the first roller and the second plurality of teeth of the second roller are configured to load the stems of the bast fibers in a shear mode to at least one of bend and break the stems.
In other features, each of the first plurality of teeth has one of a rectangular cross section and a “W”-shaped cross-section. The first plurality of teeth and the second plurality of teeth have different shapes. The first plurality of teeth and the second plurality of teeth have the same shape. The stems have a diameter. The span distance is in a range from four to seven times the diameter of the stems.
In other features, the diameter of the stems is in range from 0.5 mm to 3 mm. The span distance is in range from 2 mm to 21 mm. The bast fibers comprise flax.
A roller system for processing bast fibers includes a first roller including a first plurality of teeth; and a second roller including a second plurality of teeth having a span distance in a range from 4 to 7 times a diameter of stems of bast fibers to be processed. The first roller and the second roller are arranged such that each of the first plurality of teeth passes between adjacent pairs of the second plurality of teeth. The first plurality of teeth of the first roller and the second plurality of teeth of the second roller are configured to load the stems of the bast fibers in a shear mode to at least one of bend and break the stems.
In other features, each of the first plurality of teeth has a rectangular cross section and wherein each of the second plurality of teeth has a triangular cross-section. The first plurality of teeth and the second plurality of teeth have different shapes. The first plurality of teeth and the second plurality of teeth have the same shape. The diameter of the stems of the bast fibers is in range from 0.5 mm to 3 mm. The span distance is in range from 2 mm to 21 mm. The bast fibers comprise flax.
A roller system for processing bast fibers includes a first roller including a first plurality of teeth. A second roller includes a second plurality of teeth having a span distance. Each of the first plurality of teeth has one of a rectangular shaped cross section and a “W”-shaped cross section. Each of the second plurality of teeth has a triangular cross section. The first roller and the second roller are arranged such that each of the first plurality of teeth passes between adjacent pairs of the second plurality of teeth. The first plurality of teeth of the first roller and the second plurality of teeth of the second roller are configured to load stems of bast fibers in a shear mode to at least one of bend and break the stems.
In other features, the bast fibers have a diameter. The span distance is in a range from four to seven times the diameter of the bast fibers. The diameter of the bast fibers is in range from 0.5 mm to 3 mm. The span distance is in range from 2 mm to 21 mm. The bast fibers comprise flax.
Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.
The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:
In the drawings, reference numbers may be reused to identify similar and/or identical elements.
While the systems and methods for processing bast fibers according to the present disclosure are described below in the context of reinforcing fibers for vehicle applications such as additive manufacturing of components, the systems and methods for processing of bast fibers can be used in other applications.
Natural fibers include bast, leaf, seed, wood, and grass stem. Bast fibers include flax, hemp, jute, ramie and kenaf. Bast fibers such as flax can be used as reinforcing fibers in a polymer matrix. For example, the reinforcing fibers can be mixed with polymer and used in injection molding, molding of structural and semi-structural composites, and additive manufacturing such as 3D printing of components. Flax fibers have excellent properties for use as reinforcing fibers include such as a density of approximately 1.38 g/cm3, a tensile strength of 700 to 1000 MPa, a Young's modulus of 60-70 GPa, and an elongation of 2.3% at break.
The lengths of the fibers vary after passing through the rollers. In other words, as the fibers pass through the roller systems, the fiber is bent at predetermined fiber bend lengths and breaks the fibers at variable fiber lengths. The roller systems described herein control a bend length (a distance between adjacent bends of a fiber after passing through the roller system) of the bast fiber (such as a flax stem) to create variable length fibers with a predetermined bend length for subsequent use in semi-structural and structural composites. In some examples, the desired fiber bend length is greater than 230 μm. In some examples, the desired fiber bend length is greater than 460 μm. In some examples, the desired fiber bend length is in a range from 230 μm to 2 mm. some examples, the desired fiber bend length is in a range from 460 μm to 1 mm.
In the case of flax fibers, the length of the fiber varies after passing through the roller system. In some examples, the length of flax fibers can be as high as 30 inches (or perhaps longer). After passing through the roller system, the fibers are bent so that the fiber is not straight, but the individual bends may still be connected.
Referring now to
At 14, retting is performed. Retting involves decomposition of woody matter enclosing the fibers. At 16, scutching/breaking is performed. When the decomposed woody tissue dries, the fibers are fed through rollers of a roller system and crushed. The scutching/breaking process separates the woody matter from the fibers. At 18, combing/heckling is performed to separate coarse fiber bundles from finer bundles and to arrange the fibers generally parallel to one another. For other applications, spinning and weaving may be performed.
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In some examples, each of the first plurality of teeth 314-1, 314-2, . . . , and 314-T has rectangular tooth profile. In some examples, each of the plurality of teeth 324-1, . . . , and 324-R has a triangular profile, a rectangular profile, or another suitable tooth profile. One of the first plurality of teeth 314-1, 314-2, . . . , and 314-T is aligned or centered between an adjacent pair of the second plurality of teeth 324-1, . . . , and 324-R.
In some examples, the bast stems have a diameter in a range from 0.5 to 3 mm. A span s between the plurality of teeth 324-1, . . . , and 324-R is in a range from 4 to 7 times the thickness/diameter of the bast stems. In other words, the span is in a range from 2 mm to 21 mm.
In some examples, the bast stems have a diameter in a range from 2 to 3 mm. A span s between the plurality of teeth 324-1, . . . , and 324-R is in a range from 4 to 7 times the thickness/diameter of the bast stems. In other words, the span is in a range from 8 mm to 21 mm. The roller system 300 in
In
The roller systems described herein control a bending location of the bast fiber (such as a flax stem) to a length greater than the fiber bend length required for use in semi-structural and structural composites. In some examples, the desired fiber bending length is greater than 230 μm. In some examples, the desired fiber bending length is greater than 460 μm. In some examples, the desired fiber bending length is in a range from 230 μm to 2 mm. some examples, the desired fiber bending length is in a range from 460 μm to 1 mm.
Using a shearing process, the fiber bundle is loaded under different conditions that use a lower energy shearing failure mode to separate the fiber bundle from the stem. The fiber bending length dictates the mechanical bending/breaking process and gear tooth spacing for the roller system for bast fibers. Furthermore, the roller systems according to the present disclosure use a shear mode to drive extraction of fiber bundles from woody stems as opposed to a bending failure mode.
Referring now to
In some examples, each of the first plurality of teeth 414-1, 414-2, . . . , and 414-T has a “W”-shaped cross section (including a pair of adjacent triangular tooth sub-portions). Each of the first plurality of teeth 424-1, . . . , and 414-R has a “W”-shaped profile, a triangular profile, a rectangular profile, or another suitable tooth profile. One of the first plurality of teeth 414-1, 414-2, . . . , and 414-T is aligned or centered between an adjacent pair of the second plurality of teeth 424-1, . . . , and 414-R.
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The foregoing description is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the disclosure can be implemented in and/or combined with features of any of the other embodiments, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with one another remain within the scope of this disclosure.
Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”
In the figures, the direction of an arrow, as indicated by the arrowhead, generally demonstrates the flow of information (such as data or instructions) that is of interest to the illustration. For example, when element A and element B exchange a variety of information but information transmitted from element A to element B is relevant to the illustration, the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is transmitted from element B to element A. Further, for information sent from element A to element B, element B may send requests for, or receipt acknowledgements of, the information to element A.
