ABRASIVE SYSTEM AND METHOD OF USING THE SAME

BACKGROUND

For years, a class of abrasive articles known generically as “structured abrasive articles” has been sold commercially for use in surface finishing. Structured abrasive articles have a structured abrasive layer affixed to a backing, and are typically used in conjunction with a liquid such as, for example, water, optionally containing surfactant. The structured abrasive layer has a plurality of shaped abrasive composites (typically having minute size), each having abrasive particles dispersed a binder. In many cases, the shaped abrasive composites are precisely shaped, for example, according to various geometric shapes (e.g., pyramids). Examples of such structured abrasive articles include those marketed under the trade designation “TRIZACT” by 3M Company, St. Paul, Minnesota.

Structured abrasive articles are often used in combination with a backup pad mounted to a tool (e.g., a disk sander or a random orbit sander). In such applications, structured abrasive articles typically have an attachment interface layer (e.g., a hooked film, looped fabric, or adhesive) that affixes them to the back up pad during use.

SUMMARY

An abrading system is presented. The system includes a first vibratory structure comprising a first plurality of protrusions. The system also includes a second vibratory structure comprising a second plurality of protrusions. The system also includes an abrasive article contacting the first film. The system also includes a stroke plate coupled to the second film. When the stroke plate is activated, the first and second plurality of protrusions are configured to interlock and slip with respect to each other in a first direction.

Systems provided herein provide vibration to an abrasive article during an abrading operation, which increases the abrading efficiency and allows for a larger surface area to be used during a sanding operation than was available in previous systems.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 illustrates a schematic view showing the configuration of a super finishing apparatus.

FIGS. 2A-2C illustrate schematic views of a linear vibratory finishing apparatus in accordance with embodiments herein.

FIGS. 3A-3D illustrate schematic views of microreplicated film structures in accordance with embodiments herein.

FIG. 4 illustrates a method of abrading a workpiece in accordance with embodiments herein.

FIGS. 5A-5C illustrate images of a linear vibratory finishing system in accordance with embodiments herein.

FIGS. 6A-6B illustrates vibratory finishing systems in accordance with embodiments herein.

FIGS. 7A-7C illustrate experimental results discussed in the Examples herein.

DETAILED DESCRIPTION

FIG. 1 is a schematic view showing the configuration of a super finishing apparatus. An abrasive material product 11 is fed out of a feeding roll 12 and wound up on a rolling roll 14 via a contact roll 13. The contact roll is pushed to the outer circumferential face of the cylindrical work piece 16 by an air cylinder 15. While the cylindrical work piece 16 is rotated in the direction of the arrow, the abrasive material product is fed to the direction opposed to the direction of movement of the object face to be abraded to carry out abrading.

Currently, robotic sanders utilize abrasive discs for abrasive operations. However, it is difficult to determine when an abrasive disc needs to be replaced, and the actual method of replacement is complicated. Customers desire abrasive systems where the cutting performance is consistent over the life of the abrasive article, and that the life of the abrasive article be long, to reduce the frequency, and associated difficulty, with changing out abrasive articles for a robot repair.

Contact-wheel based sanding systems present an alternative to sanding disc systems, as they can be used in a role-to-role system and allow for a long abrasive life. Contact-wheel based systems have a small contact area which can result in an applied unit pressure become too high a pressure for a given operation. As more and more sanding and finishing operations are moving to robotic solutions, it is required that a system be compliant for surfaces that have curvature. Additionally, to allow for grinding by vibration, a system must have a holding method that allows for slippage in the direction of the feed and does not slip in the cross-direction of the feed. Although feed sanding units using contact-wheel in the sanding section, like the example of FIG. 1, there have been no feed sanding units with large flat sanding sections using a soft material.

Conventional contact wheels are not soft or flexible, which is a necessary feature for finishing surfaces with curvature or curved surfaces. Soft contact wheels are not ideal because when the wheel deforms, the soft sheet wrinkles, preventing satisfactory polishing performance. In contrast, contact wheels cannot deform, which presents difficulty in finishing curved surfaces, like a hood of a car.

A system utilizing a soft, flexible and deformable abrasive article is desired, to handle curvature of surfaces. Additionally, a flat pad offers a larger and wider surface area. The deformation will have a smaller impact on the area of the flat pad in contact with the surface because of the softness of the article.

As used herein, the term “soft,” with respect to an abrasive pad, is defined by JIS K 7312. The C hardness means hardness immediately after a pressing surface is in close contact by a testing method specified in “Spring Hardness Test Type C Testing Method” in an appendix 2 in JIS K7312: 1996. This testing method uses a spring hardness testing machine having a structure that indicates a distance of an indenter protruding from a hole at a center of the pressing surface by spring pressure being pressed to return by a test specimen when the pressing surface of the testing machine is brought into close contact with a surface of the test specimen by scale as the hardness. The measured surface of the test specimen has a size at least equal to or more than the pressing surface of the testing machine. In some embodiments, the C hardness of pads described herein is as low as about 5, or as low as about 10, or as low as about 15, or as low as about 20, or as low as about 25, or as low as about 30.

The pads described herein may be used in either a continuous feed or an intermittent feed method. In a continuous feed setup, dynamic friction is created. Therefore, the system may result in lower polishing performance and/or require equipment with stronger feeding power.

In an intermittent feed set up, dynamic friction is also produced, however static friction is also produced in the cross direction. The friction is higher stable in the cross direction, but the friction can keep the feed direction smooth.

Systems and methods herein can use a roll-to-roll feeding system in either a continuous or intermediate feed operation, which presents an improvement over disc-changing systems previously used for many finishing operations. This increases efficiency with the reduced downtime required to change discs. Additionally, disc-changing systems usually see decreased cutting over time. The ability to use a roll of abrasive material results in more stable cut rates over tame, and can result in a long use-life based on the length of the roll. And with respect to existing roll-to-roll systems, the systems and methods described herein allow for a wider surface to be available for an abrading operation, with the benefit of a softer material which allows for abrading curved surfaces.

FIGS. 2A-2C illustrate schematic views of a linear vibratory finishing apparatus in accordance with embodiments herein. FIG. 2A illustrates a perspective view of a linear vibratory finishing apparatus 100 that includes a stroke plate 110 which actuates vibratory abrasive system 150, which abrades a surface of workpiece 130. As illustrated in the side view 102 of FIG. 2B, in some embodiments a cushion 120, or pad may be present between stroke plate 110 and vibratory system 150. Cushion 120 may serve to increase and even out an applied pressure across a rectangular surface area of workpiece 130. The surface area may be substantially the width of an abrasive article, such as abrasive belt 156, and may have a length as long as stroke plate 110, in some embodiments. Cushion 120 is a soft material allowing for the applied pressure to spread across a curved surface.

FIG. 2C is an enlarged cutaway view 104, which more clearly shows the components of a vibratory system 150 in an embodiment herein. In one embodiment, a first structure 152 is coupled to a stroke plate, either directly or through a cushion 120. First structure 152 is shaped to interlock with corresponding features of a second structure 154, which contacts an abrasive article 156. For example, abrasive article 156 may be a seamless abrasive belt fed under tension through system 100, or may otherwise be a long abrasive article fed from roll-to-roll. Abrasive article 156 may be a coated abrasive article, a nonwoven abrasive article, or a bonded abrasive article. Abrasive article 156 may comprise crushed abrasive particles, formed abrasive particles, shaped abrasive particles, and/or agglomerates, composites or mixtures thereof. Abrasive article 156, as illustrated in FIG. 2C, contacts and abrades a surface of workpiece 130.

In some embodiments, first and second structure 152, 154 each include a repeating pattern of substructures that interlock as illustrated in FIG. 2C. The repeating pattern of substructures may include evenly spaced protrusions, alternating hills and valleys, or a more complex structure, such as the varying heights of teeth on a key.

In some embodiments, first and second structures 152, 154, are evenly streaked microreplicated structures. Such a configuration may better cause vibrations to be transmitted mechanically during feeding as the first and second structures 152, 154 mesh and interlock like teeth on gears. non-evenly streaked micro-replicated structures may was dynamic friction that does not transmit vibration sufficiently.

In some embodiments, first and second structures 152, 154 are formed from micro-replicated film. In some embodiments, the microreplicated film is made from a resin with flexibility and lubricity is preferable as long as the strength can be secured. For example, a polyolefin film made be used.

Use of micro-replicated film structures 152, 154 facilitates sanding of a larger surface area that was not previously possible using systems such as that illustrated in FIG. 1, which provides abrading only along the contact point between roll 13 and surface 16.

Referring back to FIG. 1, for example, if a contact wheel has a diameter of about 50 mm, a contact angle of about 60° is required to secure the frictional force. In order for the contact to follow a curved surface with the diameter and contact angle, the abrasive article 11 must be elastic. However, handling stretch web is difficult. In contrast, using a pad with film structures 152, 154, over a large surface area, the expansion and contraction is slight even following a curved surface. While the system illustrated in FIGS. 2A-2C can polish a flat surface, it presents an improved ability over prior art systems to follow curved surfaces. Cushion 120 compensates, improving the ability to manage curved surfaces. FIGS. 3A-3C illustrate schematic views of microreplicated film structures in accordance with embodiments herein. As described with respect to FIG. 2, in some embodiments a vibratory system includes a first structure 210 and a second structure 220 that allow for movement, or slippage, along a first direction 234, but no substantial slippage in a second direction 232. Slippage may be facilitated by the fitting 230 between first and second structures 210, 220. In some embodiments, fitting 230 may include a gap allowing for freedom of movement.

Structure 210, in some embodiment, includes a plurality of protrusions 212 extending from a backing 214. In some embodiments, protrusions 212 are substantially identical in height and width and spacing between adjoining protrusions. In some embodiments, protrusions 212 are of the same material as backing 214. Protrusions 212 may be coextruded, or conformed with backing 214.

Structure 220, in some embodiment, includes a plurality of protrusions 222 extending from a backing 224. In some embodiments, protrusions 222 are substantially identical in height and width and spacing between adjoining protrusions. In some embodiments, protrusions 222 are of the same material as backing 224. Protrusions 222 may be coextruded, or conformed with backing 224.

In some embodiments, fitting 230 does not include a gap, and structure 210 is substantially identical in that dimensions of protrusions 212 are identical to dimensions of protrusions 222. As illustrated in FIG. 3A, each of structures 210, 220 are defined by a width 238 and a length 236. Slippage between structures 210, 220 occurs substantially only in direction 234, along the width.

While FIGS. 3A and 3B illustrate substantially rectangular protrusions 212, 222 with rounded edges, it is expressly contemplated that other micro-replicated structures are possible, as illustrated in the comparison between FIGS. 3C and 3D.

FIG. 3C illustrates a view 250 of a pair of protrusions 260 extending from a support structure. Each of protrusions 260 is identical, having a height 256 extending from the base, a width 252, where width is substantially perpendicular to height 256, in the embodiment illustrated in FIG. 3C. Protrusions 260 are substantially rectangular in shape, with rounded edges. However, other shapes, including a greater degree of rounding, sharp corners are also explicitly envisioned. As illustrated in FIG. 3C, height 256 of protrusions 260 is a height of the protrusion only, and does not include a thickness of base 258 of structure 250.

In some embodiments, thickness 258 is sufficient to allow for stability of structure 250, but thin enough to allow for some flexibility in structure 250 as protrusions 260 vibrate.

Protrusions 260 are spaced apart from each other by space 254. As illustrated in FIG. 2C, in some embodiments, space 254 is greater than width 252, which allows for room for protrusions 260 to vibrate when in an interlocking position. In some embodiments, therefore, width 252 is less than or equal to spacing 254. Additionally, in some embodiments, the combination of spacing 254 and width 252 is less than twice height 256, as illustrated in Equation 1 below:

(width 252+spacing 254)<(2×height 256) Equation 1

In addition to providing slip prevention, referring to FIG. 3D, if the pitch is large relative to the height, the force per pitch increases. Since it is gentle, lateral slippage is more likely to occur. The value that can secure an angle of about 45° is limited to bout 2:1. FIG. 3D illustrates another configuration for protrusions 280 extending from a structure 270 with base thickness 278. Protrusions 280 have a height 276 and a total repeating width of first width 272 and second width 274. In some embodiments, the triangular-shaped protrusions 280 are isosceles triangles, such that widths 272 and 274 are the same. In other embodiments, protrusions 280 are scalene triangles, such that widths 272 and 274 are different from each other and from a total width of protrusion 280. Additionally, while widths 272 and 274 are presented such that no spacing (comparable to spacing 254) is present between adjoining protrusions, such an embodiment is expressly contemplated.

FIG. 3D illustrates an embodiment where protrusions 280 have sharp corners both at their tips and where adjoining protrusions touch. However, in other embodiments, these may be rounded. In an extreme embodiment, protrusions 280 are rounded to the point of resembling sine or cosine waves.

Additionally, in some embodiments, the combination of width 254 and width 252 is less than twice height 256, as illustrated in Equation 2 below:

(width 272+width 274)<(2×height 276) Equation 2

FIG. 4 illustrates a method of abrading a workpiece in accordance with embodiments herein.

In block 310, an abrasive article is coupled to a vibratory system. The vibratory system, in some embodiments, includes a vibration source, an abrasive feed source, and a vibration assembly. The vibration assembly may include, as described above with respect to FIGS. 2A-2C, opposing structures may be placed in interlocking positions 316 with respect to each other, and the abrasive article may be interact with only one of the structures, on a side opposite the plurality of protrusions.

Abrasive article may be moveably coupled to vibratory system, as indicated in block 312. For example, the abrasive article may be a seamless belt that is fed through the vibratory system such that a surface area of the abrasive article in contact with a workpiece is constantly, or frequently, changing during an abrasive operation. This may include abrasive article being in a non-fixed position, as indicated in block 314, with respect to the vibratory system. However, other configurations 318 are possible. For example, the abrasive article may be a coated abrasive article that is fixed to the vibratory system, for example using a hook and loop or adhesive-based coupling.

In block 320, a workpiece is abraded. The workpiece is abraded using a surface area 332 of the abrasive article in contact with the workpiece. In contrast with previous systems, such as that illustrated in FIG. 1, a square or rectangular surface area of an abrasive article is available during an abrading operation, resulting in a greater area being abraded at any given time, speeding up an abrasive operation. For example, a length and width of an abrasive area may be similar, in contrast to previous systems, such as that of FIG. 1, where the length and width of an abrading operation may differ by a factor of 5 or 10 or more.

Either the abrasive article or the workpiece may be fed through the vibratory system as a linear feed 334. For example, the abrasive article may be a seamless belt fed through the system, as illustrated in the example of FIGS. 5 and 6, presented below. Alternatively, the abrasive article may be a coated abrasive article and the workpiece may be fed through the vibratory system. However, in other embodiments 336, the vibratory system is moved with respect to a workpiece, as described with respect to the robotic repair unit embodiment of FIG. 6, discussed below.

The vibratory system, in some embodiments, vibrates during an abrading operation. The vibration may be caused by stroke plate movement 332, movement of a coupler 324, or through another movement mechanism 326.

FIGS. 5A-5C illustrate images of a linear vibratory finishing system in accordance with embodiments herein. FIG. 5A illustrates a view of a system 500, illustrating stroke directionality 510, and feed direction 520. In some embodiments, a stroke plate can facilitate vibration at rates at least as high as 30 strokes/min, or at least as high as 100 strokes/minute, or at least as high as 500 strokes/minute, or at least as high as 1000 strokes/minute, or at least as high as 5000 strokes/min, or at least as high as 8000 strokes/minute, or at least as high as 10,000 strokes/minute, or at least as high as 12,000 strokes/minute, or at least as high as 15,000 strokes/min. When the stroke is long, the number of strokes is small, and when the stroke is short, the number of strokes is large.

The system 500 is designed to receive an abrasive belt moving at a feed rate, in feed direction 520, at a rate of at least 1 mm/min, at least 10 mm/min, at least 20 mm/min, at least 50 mm/min, at least 100 mm/min, at least 150 mm/min or as high as 200 mm/min. The higher the number of strokes, the higher the feed rate, and the smaller the stroke, the lower the feed rate.

FIG. 5B illustrates a view of system 500 with an abrasive article 530 in place. As illustrated in FIG. 5B, in one embodiment, abrasive article is fed linearly through system 500. In some embodiments, an entire width 532, or substantially an entire width is available for use within system 500, allowing for a larger surface area 534 to be used during an abrading operation at a time. FIG. 5C illustrates a closer view of the feed area of system 500, including a workpiece 540.

FIGS. 6A and 6B illustrates vibratory finishing systems in accordance with embodiments herein. FIG. 6A illustrates a robotic repair mounted finishing system 600 that includes a vibratory finishing system 620 mounted to a robotic repair unit 610. Robotic repair unit 610 can automatically move finishing system 620 into place above a workpiece needing finishing work.

Vibratory finishing system 620 includes a vibratory system 622, which may include a compressible cushion that allows system 620 to provide finishing to surfaces with curvature, such as automobile hoods, doors, etc. System 622 also includes interlocking structures, such as those described with respect to FIGS. 2-3, positioned in between abrasive article 630 and stroke plate 626 such that slippage can occur in the direction perpendicular to the movement of abrasive article 630, e.g. into and out of the plane of view of FIG. 6A. Abrasive article 630, in the embodiment of FIG. 6A, is a belt that moves from one of rolls 624 to the other during an abrasive operation. The abrasive article 630 is stabilized by guides 628 which ensure that that abrasive article 630 is held tightly against vibration system 622. This may be helpful to ensure that while the interlocking structures can move into and out of the plane of FIG. 6A, they do not have enough free movement to fall out of alignment. Abrasive article 630 is maintained under tension during operation.

As described with respect to FIGS. 2-3, vibratory system 622 includes an upper and lower structure, with interlocking features that behave like gear teeth, allowing for movement in a single direction, e.g. into and out of the plane of FIG. 6A, but not in the direction of movement of abrasive article 630.

An alternative system 650 is illustrated in FIG. 6B. System 650 may also be mountable to a robotic repair unit, or may operate independently. As illustrated in FIG. 6B, an abrasive article 660 is fed from a first roll 652 to a second roll 654, under tension provided by guides 656.

A vibratory system 680 is provided that, as discussed above, includes a first and second interlocking structures that allow for slippage in direction 682, e.g. into and out of the plane of FIG. 6B. Vibratory system 680 may also include a cushion that ensures a surface area 684 of worksurface 670 is in contact with abrasive article 660 during an entirety of an abrasive operation.

Abrasive articles as described herein can be formed of any suitable material and can include any suitable abrasive particles. Suitable backings include, for example, polymeric films (including primed polymeric film), cloth, paper, foraminous and non-foraminous polymeric foam, vulcanized fiber, fiber reinforced thermoplastic backing, meltspun or meltblown nonwovens, treated versions thereof (e.g., with a waterproofing treatment), and combinations thereof. Suitable thermoplastic polymers for use in polymeric films include, for example, polyolefins (e.g., polyethylene, and polypropylene), polyesters (e.g., polyethylene terephthalate), polyamides (e.g., nylon-6 and nylon-6,6), polyimides, polycarbonates, blends thereof, and combinations thereof.

Typically, at least one major surface of the backing is smooth (for example, to serve as the first major surface).

The backing may contain various additive(s). Examples of suitable additives include colorants, processing aids, reinforcing fibers, heat stabilizers, UV stabilizers, and antioxidants. Examples of useful fillers include clays, calcium carbonate, glass beads, talc, clays, mica, wood flour; and carbon black. In some embodiments, the backing may be a composite film such as, for example, a coextruded film having two or more discrete layers.

The abrasives particles may include particles of any suitable shape and composition, including crushed abrasive particles, formed abrasive particles, precision shaped abrasive particles; and/or agglomerates, mixtures or composites thereof.

Examples of suitable abrasive particles for first and/or second sets of abrasive particles include: fused aluminum oxide; heat-treated aluminum oxide; white fused aluminum oxide; ceramic aluminum oxide materials such as those commercially available under the trade designation 3M CERAMIC ABRASIVE GRAIN from 3M Company, St. Paul, MN; brown aluminum oxide; blue aluminum oxide; silicon carbide (including green silicon carbide); titanium diboride; boron carbide; tungsten carbide; garnet; titanium carbide; diamond; cubic boron nitride; garnet; fused alumina zirconia; iron oxide; chromia; zirconia; titania; tin oxide; quartz; feldspar; flint; emery; sol-gel-derived abrasive particles; and combinations thereof. Of these, molded sol-gel derived alpha alumina abrasive particles are preferred in many embodiments. Abrasive material that cannot be processed by a sol-gel route may be molded with a temporary or permanent binder to form shaped precursor particles which are then sintered to form shaped abrasive particles, for example, as described in U. S. Pat. Appln. Publ. No. 2016/0068729 A1 (Erickson et al.).

Examples of sol-gel-derived abrasive particles and methods for their preparation can be found in U.S. Pat. No. 4,314,827 (Leitheiser et al.); U.S. Pat. No. 4,623,364 (Cottringer et al.); U.S. Pat. No. 4,744,802 (Schwabel), U.S. Pat. No. 4,770,671 (Monroe et al.); and U.S. Pat. No. 4,881,951 (Monroe et al.). It is also contemplated that the abrasive particles could include abrasive agglomerates such, for example, as those described in U.S. Pat. No. 4,652,275 (Bloecher et al.) or U.S. Pat. No. 4,799,939 (Bloecher et al.). In some embodiments, first and/or abrasive particles may be surface-treated with a coupling agent (e.g., an organosilane coupling agent) or other physical treatment (e.g., iron oxide or titanium oxide) to enhance adhesion of the abrasive particles to the binder (e.g., make and/or size layer). The abrasive particles may be treated before combining them with the corresponding binder precursor, or they may be surface treated in situ by including a coupling agent to the binder.

Preferably, first and/or second abrasive particles are ceramic abrasive particles such as, for example, sol-gel-derived polycrystalline alpha alumina particles. Abrasive particles composed of crystallites of alpha alumina, magnesium alumina spinel, and a rare earth hexagonal aluminate may be prepared using sol-gel precursor alpha alumina particles according to methods described in, for example, U.S. Pat. No. 5,213,591 (Celikkaya et al.) and U. S. Pat. Appln. Publ. Nos. 2009/0165394 A1 (Culler et al.) and 2009/0169816 A1 (Erickson et al.).

Alpha alumina-based triangular abrasive particles can be made according to well-known multistep processes. Briefly, the method includes the steps of making either a seeded or non-seeded sol-gel alpha alumina precursor dispersion that can be converted into alpha alumina; filling one or more mold cavities having the desired outer shape of the abrasive particle with the sol-gel, drying the sol-gel to form precursor triangular abrasive particles; removing the precursor abrasive particles from the mold cavities; calcining the precursor abrasive particles to form calcined, precursor abrasive particles, and then sintering the calcined, precursor abrasive particles to form the first and/or second set of abrasive particles. The process will now be described in greater detail.

Further details concerning methods of making sol-gel-derived abrasive particles can be found in, for example, U.S. Pat. No. 4,314,827 (Leitheiser); U.S. Pat. No. 5,152,917 (Pieper et al.); U.S. Pat. No. 5,435,816 (Spurgeon et al.); U.S. Pat. No. 5,672,097 (Hoopman et al.); U.S. Pat. No. 5,946,991 (Hoopman et al.); U.S. Pat. No. 5,975,987 (Hoopman et al.); and U.S. Pat. No. 6,129,540 (Hoopman et al.); and in U. S. Publ. Pat. Appln. No. 2009/0165394 A1 (Culler et al.).

In some preferred embodiments, the abrasive particles are precisely-shaped in that individual abrasive particles will have a shape that is essentially the shape of the portion of the cavity of a mold or production tool in which the particle precursor was dried, prior to optional calcining and sintering.

Abrasive particles used in the present disclosure can typically be made using tools (i.e., molds) cut using precision machining, which provides higher feature definition than other fabrication alternatives such as, for example, stamping or punching. Examples of sol-gel-derived alpha alumina (i.e., ceramic) abrasive particles can be found in U.S. Pat. No. 5,201,916 (Berg); U.S. Pat. No. 5,366,523 (Rowenhorst (Re 35,570)); and U.S. Pat. No. 5,984,988 (Berg). Details concerning such abrasive particles and methods for their preparation can be found, for example, in U.S. Pat. No. 8,142,531 (Adefris et al.); U.S. Pat. No. 8,142,891 (Culler et al.); and U.S. Pat. No. 8,142,532 (Erickson et al.); and in U. S. Pat. Appl. Publ. Nos. 2012/0227333 (Adefris et al.); 2013/0040537 (Schwabel et al.); and 2013/0125477 (Adefris).

Examples of slurry derived alpha alumina abrasive particles can be found in WO 2014/070468, published on May 8, 2014. Slurry derived particles may be formed from a powder precursor, such as alumina oxide powder. The slurry process may be advantageous for larger particles that can be difficult to make using sol-gel techniques.

The abrasive particles may undergo a sintering process, such as the process described in U.S. patent Ser. No. 10/400,146, issued on Sep. 3, 2019, for example. However, other processing techniques are expressly contemplated.

Ultra-fine grain PSG may also be used in abrasive articles described herein. Ultra-fine grain PSG can be formed using techniques described in U.S. PAP 2019/0233693, published on Aug. 1, 2019, or in WO 2018023177, published on Dec. 20, 2018, or in WO 2018/207145, published on Nov. 15, 2018.

Softer PSG particles, with Mohs hardness' between 2.0 and 5.0, that can be used for abrasive particles herein, particularly where non-scratch applications are anticipated, can be made according to methods described in WO 2019/215539, published on Nov. 14, 2019.

The shaped abrasive particles can have at least one sidewall, which may be a sloping sidewall. In some embodiments, more than one (for example two or three) sloping sidewall can be present and the slope or angle for each sloping sidewall may be the same or different. In other embodiments, the sidewall can be minimized for particles where the first and the second faces taper to a thin edge or point where they meet instead of having a sidewall. The sloping sidewall can also be defined by a radius, R (as illustrated in FIG. 5B of US Patent Application No. 2010/0151196). The radius, R, can be varied for each of the sidewalls.

Specific examples of shaped particles having a ridge line include roof-shaped particles, for example particles as illustrated, in FIG. 4A to 4C of WO 2011/068714. Preferred, roof-shaped particles include particles having the shape of a hip roof, or hipped roof (a type of roof wherein any sidewalls facets present slope downwards from the ridge line to the first side. A hipped roof typically does not include vertical sidewall(s) or facet(s)).

Methods for making shaped abrasive particles having at least one sloping sidewall are for example described in US Patent Application Publication No. 2009/0165394.

Shaped abrasive particles can also include a plurality of ridges on their surfaces. The plurality of grooves (or ridges) can be formed by a plurality of ridges (or grooves) in the bottom surface of a mold cavity that have been found to make it easier to remove the precursor shaped abrasive particles from the mold.

Methods for making shaped abrasive particles having grooves on at least one side are for example described in US Patent Application Publication No. 2010/0146867.

The shaped abrasive particles may also have one or more notches on one of the faces of the abrasive particle, as described in PCT Application Ser. No. IB2019/060861, filed on Dec. 16, 2019.

Shaped abrasive particles can have an opening (preferably one extending or passing through the first and second side). Methods for making shaped abrasive particles having an opening are for example described in US Patent Application Publication No. 2010/0151201 and 2009/0165394.

Shaped abrasive particles can also have at least one recessed (or concave) face or facet; at least one face or facet which is shaped outwardly (or convex). Methods for making dish-shaped abrasive particles are for example described in US Patent Application Publication Nos. 2010/0151195 and 2009/0165394. Additionally, shaped abrasive particles may also have a multifaceted surface as described in U.S. Pat. No. 10,150,900, issued on Dec. 11, 2018.

Shaped abrasive particles can also have at least one fractured surface. Methods for making shaped abrasive particles with at least one fractured surface are for example described in US Patent Application Publication Nos. 2009/0169816 and 2009/0165394.

Shaped abrasive particles can also have a cavity. Shaped abrasive particles may also include an aperture, such as that described in U.S. Pat. No. 8,142,532, issued on Mar. 27, 2012, herein incorporated by reference.

Shaped abrasive particles can also have a low roundness factor. Methods for making shaped abrasive particles with low Roundness Factor are for example described in US Patent Application Publication No. 2010/0319269.

Shaped abrasive particles may have a second vertex on a second side, as described in U.S. Pat. No. 9,447,311, issued on Sep. 16, 2016. Methods for making abrasive particles wherein the second side is a vertex (for example, dual tapered abrasive particles) or a ridge line (for example, roof shaped particles) are for example described in U.S. PAP 2012/022733, published on Sep. 13, 2012.

Shaped abrasive particles may be formed to have sharp tips, such as those described in U.S. PAP 2019/0233693, published on Aug. 1, 2019, or in U.S. Provisional Application with Ser. No. 62/877,443, filed on Jul. 23, 2019.

Shaped abrasive particles may also be formed to include a rake angle, such as those described in WO 2019/207423, published on Oct. 31, 2019, or in WO 2019/207417, published on Oct. 31, 2019, or in PCT Application Ser. No. IB 2019/059112, filed on Oct. 24, 2019.

Shaped abrasive particles may also be formed to have a precision shaped portion and a non-shaped portion, such as a crushed portion, as described in U.S. Provisional Patent Application 62/833,865, filed on Apr. 15, 2019.

Shaped abrasive particles can also have a combination of one or more of shape features discussed herein, including a sloping sidewall, a groove, a recess, a facet, a fractured surface, a cavity, more than one vertex, sharp edges, a non-shaped portion, a notch, a rake angle and/or a low roundness factor.

Additionally, the shaped abrasive particles may be agglomerates of shaped and/or crushed abrasive particles.

As used herein in referring to triangular abrasive particles, the term “length” refers to the maximum dimension of a triangular abrasive particle. “Width” refers to the maximum dimension of the triangular abrasive particle that is perpendicular to the length. The terms “thickness” or “height” refer to the dimension of the triangular abrasive particle that is perpendicular to the length and width. For abrasive particles with shapes other than triangles, length refers to a longest dimension, and width refers to the maximum dimension perpendicular to the length, while thickness refers to a dimension perpendicular to both the length and width.

The shaped abrasive particles may have an elongated shape, such as that described in U.S. PAP 2019/0106362, published on Apr. 11, 2019, or in WO 2019/069157, published on Apr. 11, 2019. The elongate shape may be triangular-prism shaped, rod-shaped, or otherwise including one or more vertices along the perimeter.

The shaped abrasive particles may have a variable cross-sectional area along a length of the particle, such as those described in U.S. PAP 2019/0249051. For example, the shaped abrasive particles may be dog-bone shaped, or otherwise have a cross sectional area that varies from a first end to a second end.

The shaped abrasive particles may have a tetrahedron shape, such as those described in WO 2018/207145, published on Nov. 15, 2018, or those of U.S. Pat. No. 9,573,250, issued on Feb. 21, 2017.

The shaped abrasive particles may also have a concave or convex portion, or may be defined as having one or more acute interior angles, such as those described in U.S. Pat. No. 10,301,518, issued on May 28, 2019.

The shaped abrasive particles may also include shape-on-shape particles, such as a plate on plate shaped particle as described in U.S. Pat. No. 8,728,185, issued on May 20, 2014.

The shaped abrasive particles may also include shaped abrasive particles that have an irregular polygonal shape, as described in U.S. Provisional Patent Application 62/924,956, filed on Oct. 23, 2019.

The shaped abrasive particles may also be shaped to be self-standing abrasive particles, such that cutting portions are more likely to embed in a make coat, for example, in an orientation away from the backing, such as those described in PCT Application with Ser. No. IB 2019/060457, filed on Dec. 4, 2019.

The shaped abrasive particles can also be aggregate particles. The aggregate particles may include shaped abrasive particles in a vitreous bond matrix as described, for example, in U.S. PAP 2018/081246, published on May 3, 2018. The aggregate particles may also include shaped abrasive particles in a silicate binder, as described in WO 2019/167022, published on Sep. 6, 2019. The aggregate particles may also include frustro-pyrimidal shaped particles in a vitreous bond matrix, as described in US PAP 2019/0283216, published on Sep. 19, 2019. The aggregate may also include a mixture of crushed and shaped particles, as described in PCT Publication IB/2019/058349, filed on Oct. 1, 2019.

The abrasive grain may have a surface treatment thereon. In some instances, the surface treatment may increase adhesion to the binder, alter the abrading characteristics of the abrasive particle, or the like. Examples of surface treatments include coupling agents, halide salts, metal oxides including silica, refractory metal nitrides, and refractory metal carbides.

The abrasive layer may also comprise diluent particles, typically on the same order of magnitude as the abrasive particles. Examples of such diluent particles include gypsum, marble, limestone, flint, silica, glass bubbles, glass beads, and aluminum silicate.

Abrasive articles and vibratory finishing systems described herein may be suitable for a variety of workpieces having material and may have any form. Examples of materials include metal, metal alloys, exotic metal alloys, ceramics, painted surfaces, plastics, polymeric coatings, stone, polycrystalline silicon, wood, marble, and combinations thereof. Examples of workpieces include molded and/or shaped articles (e.g., optical lenses, automotive body panels, boat hulls, counters, and sinks), wafers, sheets, and blocks.

Depending upon the application, the force at the abrading interface can range from about 0.1 kg to over 1000 kg. Generally, this range is between 1 kg to 500 kg of force at the abrading interface. Also, depending upon the application there may be a liquid present during abrading. This liquid can be water and/or an organic compound. Examples of typical organic compounds include lubricants, oils, emulsified organic compounds, cutting fluids, surfactants (e.g., soaps, organosulfates, sulfonates, organophosphonates, organophosphates), and combinations thereof. These liquids may also contain other additives such as defoamers, degreasers, corrosion inhibitors, and combinations thereof.

Objects and advantages of this invention are further illustrated by the following non-limiting examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and, details, should not be construed to unduly limit this invention.

An abrading system is presented that includes a first vibratory structure comprising a first plurality of protrusions, a second vibratory structure comprising a second plurality of protrusions, an abrasive article contacting the first film, and a stroke plate coupled to the second film. When the stroke plate is activated, the first and second plurality of protrusions are configured to interlock and slip with respect to each other in a first direction.

The abrading system may be implemented such that the abrasive article is a rolled sheet of abrasive fed through the abrading system in a feeding direction. The feeding direction is perpendicular to the first direction.

The abrading system may be implemented such that the abrasive article is a coated abrasive article, a bonded abrasive article or a nonwoven abrasive article.

The abrading system may be implemented such that the abrasive article includes abrasive particles. The abrasive particles include crushed, formed, or shaped abrasive particles.

The abrading system may be implemented such that the first plurality of protrusions include a shaped protrusion repeating along a surface of the first vibratory structure.

The abrading system may be implemented such that the shaped protrusion repeats along the surface of the first vibratory structure at regular intervals.

The abrading system may be implemented such that the regular intervals include a space length between adjacent protrusions that is greater than a protrusion width.

The abrading system may be implemented such that a sum of the regular interval and the protrusion width is less than or equal to twice a height of the shaped protrusion.

The abrading system may be implemented such that the shaped protrusion is a rectangular shaped protrusion.

The abrading system may be implemented such that the shaped protrusion includes a triangular shaped protrusion.

The abrading system may be implemented such that the shaped protrusion has a rounded corner.

The abrading system may be implemented such that the first and second vibratory structures include microreplicated film.

The abrading system may be implemented such that the microreplicated film includes a resin.

The abrading system may be implemented such that the microreplicated film includes a polyolefin.

The abrading system may be implemented such that it includes a compressible pad between the stroke plate and the second vibratory structure.

A robotic repair system is presented that includes an abrading system with a vibration source, a first structure, with a first interlocking feature, coupled to the vibration source, and a second structure, with a second interlocking feature interlocked to the first locking feature. The first and second structures are configured to, when interlocked, slip in a first direction. An abrasive article contacts the second structure on a second side opposite a first side that contacts the first structure. The abrading system also includes a robotic repair unit configured to move the abrading system into position over a workpiece and a mount that couples the abrading system to the robotic repair unit.

The robotic repair system may be implemented such that the abrasive article is an abrasive belt. The abrading system also includes a belt feeder that feeds the belt in between the second structure and the workpiece, in a feed direction. The feed direction is different from the first direction.

The robotic repair system may be implemented such that the feed direction is perpendicular to the first direction.

The robotic repair system may be implemented such that, during an abrasive operation, a surface area of the abrasive belt contacts the workpiece. The surface area of the abrasive article includes a dimension of the second structure and a width of the abrasive belt.

The robotic repair system may be implemented such that the abrasive belt is fed from a first belt roll to a second belt roll.

The robotic repair system may be implemented such that it also includes a cushion in between the vibration source and the first structure.

The robotic repair system may be implemented such that the vibration source is a stroke plate.

The robotic repair system may be implemented such that the abrasive article is an abrasive pad coupled to the second structure.

The robotic repair system may be implemented such that the abrasive article includes abrasive particles. The abrasive particles include crushed, formed or shaped abrasive particles.

The robotic repair system may be implemented such that the abrasive article is a coated, bonded or nonwoven abrasive article.

The robotic repair system may be implemented such that the first and second interlocking features are micro-replicated features.

The robotic repair system may be implemented such that the first and second interlocking features each include a plurality of protrusions extending from a base surface. The robotic repair system may be implemented such that, when in an interlocking position, a plurality of spaces are present between the first and second interlocking features.

The robotic repair system may be implemented such that the plurality protrusions include a repeating shape.

The robotic repair system may be implemented such that the repeating shape is rectangular or triangular.

The robotic repair system may be implemented such that the repeating shape is a polygon adjacent a space.

The robotic repair system may be implemented such that the length of the repeating shape is less than or equal to twice a height of the repeating shape.

A method of abrading a surface that includes coupling an abrasive article to an abrading system. The abrading system includes a vibration source and a first structure coupled to the vibration source. The first structure includes a first plurality of protrusions extending from a first base. The abrading system also includes a second structure comprising a second plurality of protrusions, extending from a second base. The second plurality of protrusions interlock with the first plurality of protrusions. The abrasive article is coupled to the second structure. The method also includes actuating the abrading system. Actuating the abrading system causes the first and second plurality of protrusions to slip with respect to each other in a first direction.

The method may be implemented such that it also includes causing the abrasive article to move with respect to the workpiece in a feed direction.

The method may be implemented such that the workpiece remains stationary, the abrasive article is physically attached to the second structure, and causing the abrasive article to move includes moving the abrading system using a robotic repair unit.

The method may be implemented such that the workpiece remains stationary, the abrasive article is an abrasive belt. Causing the abrasive article to move includes feeding the abrasive belt, under tension, from a feed roll to a rolling roll.

The method may be implemented such that a feeding direction is opposite the first direction. The first and second plurality of protrusions substantially prohibit slippage in the feeding direction.

The method may be implemented such that the first plurality of protrusions are micro-replicated.

The method may be implemented such that the first plurality of protrusions are machined into the first structure.

The method may be implemented such that the first plurality of protrusions are formed of the same material as the first base.

The method may be implemented such that the first plurality of protrusions are integral to the first base.

The method may be implemented such that the first plurality of protrusions have a first protrusion height, the second plurality of protrusions have a second protrusion height, and the first and second protrusions heights are the same.

The method may be implemented such that the first and second plurality of protrusions interlock such that gaps are present between adjacent protrusions.

The method may be implemented such that the first plurality of protrusions are polygonal in shape.

The method may be implemented such that the polygonal shape is substantially rectangular or substantially triangular.

The method may be implemented such that the vibration source is a stroke plate.

The method may be implemented such that a cushion is present between the vibration source and the first structure.

An abrasive article is presented that includes a substrate longer in a first direction than a second direction. The abrasive article also includes a plurality of protrusions on the substrate. The protrusions extend in the second direction. The protrusions are in a repeating pattern on the substrate.

The abrasive article may be implemented such that the substrate has a first side, comprising the protrusions, and a second side. The second side includes a plurality of abrasive particles configured to contact a work surface.

The abrasive article may be implemented such that the substrate has a first side, comprising the protrusions, and a second side. The second side contacts a cushion.

The abrasive article may be implemented such that the abrasive article is a coated abrasive article, a bonded abrasive article or a nonwoven abrasive article.

The abrasive article may be implemented such that the abrasive article includes abrasive particles. The abrasive particles include crushed, formed, or shaped abrasive particles.

The abrasive article may be implemented such that the repeating pattern includes a space length between adjacent protrusions that is greater than a protrusion width.

The abrasive article may be implemented such that a length of a first edge of a first protrusion and a corresponding first edge of a second protrusion is less than or equal to twice a height of the shaped protrusion.

The abrasive article may be implemented such that abrasive article is rolled around a core.

The abrasive article may be implemented such that the abrasive article is on the core side.

The abrasive article may be implemented such that the protrusions are on the core side.

Examples

FIGS. 7A-7C illustrate experimental results discussed in the Examples herein. An abrasive was obtained from 3M company, model 373L, 30 mic. The abrasive was adhered to microreplicated film as described herein, with dimensions of a+a′=230 μm and b=150 μm. The workpiece was an SUS 304. The machine illustrated in FIGS. 5A-5C was used, and the abrasive article was handfed through the machine. The pad size was 25 mm×50 mm×10 mm in height. A sponge was used as the pad to provide cushion. A load of 15.7N was applied.

FIG. 7A illustrates the cut rate comparing a pad as described above, labeled as “Example A” compared to a traditional pad. FIG. 7B illustrates the pad of Example A after a grinding operation with vibratory scratching, while FIG. 7C illustrates the pad of Example A with feeding scratch only. More abrading is illustrated when the vibrations are observed.

Various modifications and alterations of this invention may be made by those skilled in the art without departing from the scope and spirit of this invention, and it should be understood that this invention is not to be unduly limited to the illustrative embodiments set forth herein.

ABRASIVE SYSTEM AND METHOD OF USING THE SAME

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