Patent Application
20080280541
This disclosure relates to abrasive articles, more specifically to abrasive filaments, articles containing abrasive filaments and methods of using the same.
Polyamide, (nylon), filaments have been utilized since the 1950's as an alternative to natural filaments. An extrusion process was developed for dispersing abrasive particles uniformly in a nylon matrix in the form of a filament (U.S. Pat. Nos. 3,522,342 and 3,947,169). As polyamide filaments wear, new abrasive particles are exposed. Brushes utilizing such filaments are therefore considered to be regenerated during use.
Brushes incorporating abrasive bristles or filaments have been used for many years to polish, clean and abrade a wide variety of substrates. These brush products typically have a plurality of bristles or filaments that contact the substrate during an abrading process. The brushes are generally made by mixing abrasive particles and any suitable thermoplastic binder together and then extruding the composition to form a bristle or abrasive filament. The abrasive filament is then cut to the desired length. A plurality of these abrasive filaments are then mechanically or adhesively combined to form a brush segment. A plurality of these brush segments may be installed on a hub or plate to form a brush.
Brushes including silicon carbide- or brown aluminum oxide-loaded filaments are widely commercially available. However, there is always a need for economical brushes having better performance characteristics.
The present disclosure provides a method of deburring a substrate having at least one burr, with a brush, the brush comprising bristles comprising eutectic alumina zirconia particles and a matrix of thermoplastic polymer, wherein the method comprises the steps of: contacting the substrate with at least one bristle of the brush in a contact region; and inducing relative motion between the substrate and the at least one bristle.
The present disclosure also provides a method of refining a substrate wherein the abrading efficiency exceeds 1.0.
The present disclosure also provides an abrasive filament comprising: a matrix of thermoplastic polymer; and a plurality of eutectic alumina zirconia particles interspersed throughout at least a portion of the matrix wherein the refining efficiency exceeds 1.0.
The present disclosure also provides an abrasive brush comprising: a plurality of abrasive filaments, said filaments comprising a matrix of thermoplastic polymer and a plurality of eutectic alumina zirconia particles interspersed throughout at least a portion of said matrix; and a securing element that functions to secure the plurality of abrasive filaments to form a brush wherein the refining efficiency exceeds 1.0.
a illustrates cut, wear, and efficiency data from testing of various polyamide abrasive brushes on a perforated steel plate;
b illustrates cut, wear, and efficiency data from testing of various thermoplastic elastomer abrasive brushes on a perforated steel plate;
a illustrates cut, wear, and efficiency data from testing of various polyamide abrasive brushes on a steel plate;
b illustrates cut, wear, and efficiency data from testing of various thermoplastic elastomer brushes on a steel plate;
a illustrates cut, wear, and efficiency data from testing of various polyamide abrasive brushes on an aluminum plate;
b illustrates cut, wear, and efficiency data from testing of various thermoplastic elastomer brushes on aluminum plate;
a illustrates cut data from testing of various polyamide abrasive brushes on a steel plate;
b illustrates cut data from testing of various thermoplastic elastomer abrasive brushes on a steel plate;
a illustrates cut data from testing of various polyamide abrasive brushes on an aluminum plate;
b illustrates cut data from testing of various thermoplastic elastomer abrasive brushes on an aluminum plate;
a illustrates burr height data from testing of various polyamide abrasive brushes on a perforated steel plate; and
b illustrates burr height data from testing of various thermoplastic elastomer abrasive brushes on a perforated steel plate.
These figures, which are idealized, are intended to be merely illustrative of the abrasive article of the present disclosure and non-limiting.
It is to be understood that embodiments beyond what are mentioned here are contemplated and may be made without departing from the scope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense.
All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein and are not meant to limit the scope of the present disclosure.
Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.
The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range.
As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
Disclosed herein is an abrasive filament. The first type of abrasive filaments include a thermoplastic matrix with abrasive particles nearly uniformly interspersed in the matrix. In one embodiment, the abrasive particles are substantially uniformly interspersed throughout the thermoplastic matrix. This first type of filament results in a substantially homogeneous abrasive filament. The other type, of which there are numerous sub-types include a sheath and a core, wherein the sheath and core are generally made from different materials. Such filaments are disclosed in U.S. Pat. No. 5,427,595, “Abrasive Filaments Comprising Abrasive-Filled Thermoplastic Elastomer, Method of Making Same, Articles Incorporating Same and Methods of Using Said Articles,” (Pihl et al.); in U.S. Pat. No. 5,460,883, “Composite Abrasive Filaments, Methods of Making Same, Articles Incorporating Same, and Methods of Using Said Articles,” (Barber, Jr., et al); and in U.S. Pat. No. 6,352,471, “Abrasive Brush with Filaments Having Plastic Abrasive Particles Therein,” (Bange et al.), the entire disclosures of which are incorporated herein by reference.
As used herein, the term “interspersed” means that the abrasive particles are embedded within and located throughout the thermoplastic material that forms the filament. In the case of the core/sheath embodiments, “interspersed” means that the abrasive particles are embedded within and located throughout the thermoplastic matrix that forms the core or sheath, or both, as appropriate. The particles are interspersed so as to create a substantially homogenous distribution, though not necessarily an absolutely homogenous distribution. Furthermore, while the majority of the particles are wholly embedded within the thermoplastic matrix, there may be some exposed particles at the surface that extend partially outside of the thermoplastic matrix.
In one embodiment, an abrasive filament as described herein can have an aspect ratio of at least about 1. In an embodiment, the aspect ratio can be at least about 5. In an embodiment, the aspect ratio can be at least about 10. In an embodiment, the aspect ratio can be at least about 20. The aspect ratio is defined as the length divided by the arithmetic average width. The filaments can be of any length or width desired, and the cross-sectional shape can be for example, round, oval, square, triangular, rectangular, polygonal, or multilobal (such as trilobal, tetralobal, and the like) in cross-section. Additionally, the abrasive filaments may have a variable cross sectional area. For example, the filaments can be “wavy” or textured. Likewise, the filaments can be tapered.
The diameter of the abrasive filaments can generally range from about 0.01 to 100 mm. In an embodiment the diameter can range from about 0.05 mm to 50 mm. In an embodiment the diameter can range from about 0.1 mm to 25 mm. In an embodiment the diameter can range from about 0.2 mm to 10 mm. In an embodiment the diameter can range from about 0.25 mm to 5 mm. The length of the filament, or trim length, can range from about 1 to 1000 millimeters. In an embodiment the length of the filament can range from about 2 to 100 mm. In an embodiment the length of the filament can range from about 3 to 75 mm. In an embodiment the length of the filament can range from about 4 to 50 mm. In an embodiment the length of the filament can range from about 5 to 50 mm.
Abrasive filaments as disclosed herein include a thermoplastic matrix and a plurality of abrasive particles. As used herein, “thermoplastic matrix” refers to a material that is capable of being heated to a molten state and then subsequently cooled to a solid state. The thermoplastic matrix can be any thermoplastic polymer or thermoplastic elastomer. Examples of particular materials that can be used as the thermoplastic matrix include, but are not limited to, polyamides, such as Nylon 6,12; and Hytrel® thermoplastic elastomers.
Abrasive filaments as described herein also include abrasive particles. The abrasive particles typically have a particle size ranging from about 0.01 to 1000 micrometers, usually between about 1 to 150 micrometers. In one embodiment the abrasive particles have a Mohs hardness of at least about 7. In an embodiment, the abrasive particles have a Mohs hardness of at least about 9. Examples of such abrasive particles include, but are not limited to, fused aluminum oxide, ceramic aluminum oxide, boron carbide, titanium diboride, heated treated aluminum oxide, silicon carbide, alumina zirconia, diamond, ceria, cubic boron nitride, garnet and combinations thereof.
In an embodiment, an abrasive filament as described herein includes eutectic alumina zirconia abrasive particles. A eutectic or eutectic mixture is a mixture of two or more phases at a composition that has the lowest melting point, and where the phases simultaneously crystallize from molten solution at this temperature. Eutectic alumina zirconia can be produced by melting alumina, baddeleyite (Zr02), and other additives in an electric arc furnace. The molten product is cooled down rapidly on special cooling aggregates in order to obtain a microcrystalline and homogeneous crystal structure. Eutectic alumina zirconia is commercially available from, for example, Triebacher Schleifmittel (Villach, Austria).
In one embodiment, the eutectic alumina zirconia particles have an angular grain shape. In an embodiment, the eutectic alumina zirconia particles include from about 50 to 60 percent by weight of alumina. In an embodiment, the eutectic alumina zirconia particles include from about 52 to 56 percent by weight of alumina. In an embodiment, the eutectic alumina zirconia particles include from about 54 to 55 percent by weight of alumina. In an embodiment, the eutectic alumina zirconia particles include about 54.5 percent by weight of alumina. In an embodiment, the eutectic alumina zirconia particles include from about 35 to 45 percent by weight of zirconia. In an embodiment, the eutectic alumina zirconia particles include from about 40 to 43 percent by weight of zirconia. In an embodiment, the eutectic alumina zirconia particles include from about 41 to 42 percent by weight of zirconia. In an embodiment, the eutectic alumina zirconia particles include about 41.5 percent by weight of zirconia.
In an embodiment, eutectic alumina zirconia particles can also include other compounds. In an embodiment, the eutectic alumina zirconia particles include titanium dioxide (TiO2) and iron oxide (Fe2O3). In an embodiment, the eutectic alumina zirconia particles contain from about 2 to 3 percent by weight TiO2; in another embodiment about 2.5 percent by weight TiO2. In an embodiment, the eutectic alumina zirconia particles contains from about 0.1 to 0.5 percent by weight Fe2O3; in another embodiment about 0.2 percent by weight Fe2O3.
Abrasive filaments as disclosed herein can include abrasive particles of any size. In one embodiment, abrasive filaments can include abrasive particles having a grain size from P16 Grit to P400 Grit, using the FEPA test method. In an embodiment, abrasive filaments include abrasive particles having a grain size (FEPA) of P16, P20, P24, P30, P36, P40, P50, P60, P80, P100, P120, P150, P180, P220, etc.
In an embodiment, the abrasive filament include from about 10 to 90 percent by weight of thermoplastic matrix, such as polyamide or thermoplastic elastomer. In an embodiment, the abrasive filament includes from about 50 to 80 percent by weight of thermoplastic matrix, such as polyamide or thermoplastic elastomer. In an embodiment, the abrasive filament includes from about 55 to 75 percent by weight of thermoplastic matrix, such as polyamide or thermoplastic elastomer. In an embodiment, the abrasive filament includes from about 10 to 90 percent by weight of abrasive particles, such as eutectic alumina zirconia particles. In an embodiment, the abrasive filament includes from about 20 to 50 percent by weight of abrasive particles, such as eutectic alumina zirconia particles. In an embodiment, the abrasive filament includes from about 25 to 45 percent by weight of abrasive particles, such as eutectic alumina zirconia particles.
Additives may also be added to the abrasive filaments during manufacture. Additives such as lubricants, soaps, antioxidants, UV stabilizers, dye, pigments, wetting agents, surfactants, plasticizers, anti-static agents, anti-rust agents, and other liquid materials may be added to the filaments. One method of incorporating these types of materials into the thermoplastic matrix is to encapsulate the liquid materials into a shell that is able to withstand the extrusion temperatures. Such methods are generally well known in the art. The amounts of these materials would generally be selected to provide desired properties as would be known to those of skill in the art.
Abrasive filaments can also optionally include other additives, such as, for example, fillers (including grinding aids), fibers, antistatic agents, lubricants, wetting agents, surfactants, pigments, dyes, coupling agents, anti-rust agents, plasticizers, and suspending agents, Such additives can be blended directly into the thermoplastic matrix or can be added by other methods known to those of skill in the art. The amounts of these materials would generally be selected to provide desired properties as would be known to those of skill in the art.
Inorganic based particulate fillers can also be incorporated along with the abrasive particles. Examples of useful fillers include but are not limited to metal carbonates (such as calcium carbonate (chalk, calcite, marl, travertine, marble and limestone), calcium magnesium carbonate, sodium carbonate, magnesium carbonate), silica (such as quartz, glass beads, glass bubbles and glass fibers), silicates (such as talc, clays (montmorillonite), feldspar, mica, calcium silicate, calcium metasilicate, sodium aluminosilicate, sodium silicate), metal sulfates (such as calcium sulfate, barium sulfate, sodium sulfate, aluminum sodium sulfate, aluminum sulfate), gypsum, vermiculite, wood flour, aluminum trihydrate, carbon black, metal oxides (such as calcium oxide (lime), aluminum oxide, titanium dioxide), and metal sulfites (such as calcium sulfite).
A grinding aid is defined as particulate material that the addition of which has a significant effect on the chemical and physical processes of abrading which results in improved performance. In particular, it is believed that the grinding aid will either 1) decrease the friction between the abrasive grains and the workpiece being abraded, 2) prevent the abrasive grain from “capping”, i.e. prevent metal particles from becoming welded to the tops of the abrasive grains, 3) decrease the interface temperature between the abrasive grains the workpiece or 4) decrease the grinding forces. In general, the addition of a grinding aid increases the useful life of the abrasive filament. Grinding aids encompass a wide variety of different materials and can be inorganic or organic based. Examples of chemical groups of grinding aids include waxes, organic halide compounds, halide salts and metals and their alloys. The organic halide compounds will typically break down during abrading and release a halogen acid or a gaseous halide compound. Examples of such materials include but are not limited to chlorinated waxes like tetrachloronaphtalene, pentachloronaphthalene; and polyvinyl chloride. Examples of halide salts include but are not limited to sodium chloride, potassium cryolite, sodium cryolite, ammonium cryolite, potassium tetrafluoroboate, sodium tetrafluoroborate, silicon fluorides, potassium chloride, magnesium chloride. Examples of metals include, but are not limited to, tin, lead, bismuth, cobalt, antimony, cadmium, iron titanium. Other miscellaneous grinding aids include sulfur, organic sulfur compounds, graphite and metallic sulfides.
Examples of antistatic agents include, but are not limited to, graphite, carbon black, vanadium oxide, humectants, and the like.
The filament may also optionally include a toughening material. Examples of such toughening materials include, but are not limited to, rubber type polymers and plasticizers. Specific examples of toughening materials include toluene sulfonamide derivatives, styrene butadiene copolymers, polyether backbone polyamide (commercially available from Arkema, Inc., under the trade designation PEBAX), rubber grafted onto polyamide (commercially available from duPont under the trade designation “ZYTEL FN”) and a triblock polymer of styrene-(ethylene butylene)-styrene (commercially available from Kraton Polymers LLC, under the trade designation “KRATON 1901 X”).
Abrasive filaments as described herein may be incorporated into a wide variety of brushes, either assembled to form an open, lofty abrasive pad, or attached to various substrates. Abrasive brushes, as disclosed herein include a plurality of abrasive filaments as disclosed herein, and a securing element. Generally, the securing element functions to secure the plurality of abrasive filaments to form a brush.
The filaments disclosed herein can be incorporated into brushes of many types and for myriad uses, such as cleaning, deburring, radiusing, imparting decorative finishes onto metal, plastic, and glass substrates, and like uses. Brush types include wheel brushes, cylinder brushes (such as printed circuit cleaning brushes), mini-grinder brushes, floor scrubbing brushes, cup brushes, end brushes, flared cup end brushes, circular flared end cup brushes, coated cup and variable trim end brushes, encapsulated end brushes, pilot bonding brushes, tube brushes of various shapes, coil spring brushes, flue cleaning brushes, chimney and duct brushes, and the like. The filaments in any one brush can of course be the same or different. A non-limiting list of exemplary brushes in which the abrasive filaments described herein can be used include brushes such as those described in U.S. Pat. Nos. 5,016,311, 5,083,840, and 5,233,719 (Young et al.), and U.S. Pat. No. 5,400,458 (Rambosek), the disclosures of which are incorporated herein by reference.
In general, one such brush construction has a securing element that includes a base layer, and a binder layer. The abrasive filaments, or bristles are individually and uniformly embedded in the binder layer such that they project upward and are generally parallel to one another. The base layer and the binder layer can be the same material or different materials and in general these layers are polymeric materials. For example the base layer can be a flexible resilient polymeric open cell foam, a polyester material or a polyamide material. In addition, a cotton, polyamide or polyester fabric can be incorporated into these polymeric materials. The binder layer is usually a semi-rigid polymeric material such as a polyurethane, polyester, epoxy or polyamide. In an embodiment where the base layer and the binder layer are the same, they can be made of a polyurethane material. In general the thickness of the base layer and binder layers can range between about 1 to 10 millimeters. In another embodiment, from about 2 to 5 millimeters. The larger the diameter of the bristles, the thicker the binder layer is. An abrasive brush that includes an abrasive filament as described herein can be mounted via the securing element to an apparatus capable of inducing relative motion between a substrate and at least one of the abrasive filaments.
An abrasive brush can include only abrasive filaments described herein. Alternatively, an abrasive brush can comprise a mixture of abrasive filaments described herein and polymeric filaments. Such polymeric filaments include those without abrasive particles, and those including abrasive particles.
The polymeric filaments can include filaments made of, for example, polyamide, polypropylene, polyester, thermoplastic elastomer and polyethylene. In some cases the filaments can be hollow, which is well known in the brush art. In addition the polymeric filaments may contain abrasive particles such as those well known in the art like silicon carbide and aluminum oxide. The particle size of these abrasive particles will vary depending upon the application, but in general they can range from about 10 to 1000 micrometers. In another embodiment from about 15 to 120 micrometers.
In some brushes the filaments will be nearly perpendicular to the binder layer, in other applications such as conveyor systems, the filaments will be placed at a specified angle or a specified tilt.
In another embodiment a bristle having abrasive particles with materials encapsulated therein are included. Examples of encapsulated materials can include soaps, lubricants, anti-rust agents, and anti-static agents. In an embodiment, phosphoric acid (or a similar material) can be added to a bristle comprising abrasive particles. A brush made with such bristles would be useful in the removal and/or neutralization of surface rust on articles such as, for example, automobiles, benches, and swingsets.
One embodiment as described herein can include a unitary injection molded abrasive brush. Such molded brushes can be made as described in co-pending U.S. Pat. No. 5,679,067, “Molded Abrasive Brush,” (Johnson et al.), the entire disclosure of which is incorporated herein by reference. In such a brush, a securing element can include a threaded stud. The bristles can have an aspect ratio of at least about 2 and can be integrally molded with the base. The molded abrasive brush comprises a thermoplastic matrix having abrasive particles interspersed throughout at least the bristles. The bristles extend generally perpendicular to the base layer, parallel to the axis of rotation of the molded abrasive brush.
Another example of a unitary injection molded brush can be made as is disclosed in U.S. Pat. No. 5,903,951, “Radial Brush Segment,” (lonta et al.), the entire disclosure of which is incorporated herein by reference. The brush segment can be molded from a thermoplastic matrix having a plurality of abrasive particles interspersed throughout at least the bristles. The molded brush segments can be generally circular, with the bristles extending radially outward in the plane defined by the central portion. A plurality of brush segments can be combined to form a brush assembly.
In one embodiment, the securing element includes a cylindrical hub. Generally, the abrasive filaments are bonded to the cylindrical hub. One of skill in the art would know, having read this specification, how to manufacture such an abrasive brush.
The workpiece can be any type of material such as metal, metal alloys, exotic metal alloys, ceramics, glass, wood, wood like materials, composites, painted surface, plastics, reinforced plastic, stones, and combinations thereof. The workpiece may also contain an unwanted layer or coating external over the workpiece surface. This coating may be for example paint, dirt, debris, oil, oxide coating, rust, adhesive, gasket material and the like. The workpiece may be flat or may have a shape or contour associated with it.
In an embodiment, the workpiece is aluminum. In one embodiment, the workpiece has at least one burr. A workpiece that includes at least one burr can generally be a perforated piece. In one embodiment, the workpiece is carbon steel.
Depending upon the application, the force at the abrading interface or contact region can range from about 0.98 N to over 980 N. Generally this range is between about 9.8 N to 490 N of force at the abrading interface. Also depending upon the application, there may be a liquid present during abrading. This liquid can be water, an organic compound, a mixture comprising water and oil, or combinations thereof. Examples of typical organic compounds include lubricants, oils, emulsified organic compounds, cutting fluids, soaps, or the like. These liquids may also contain other additives such as defoamers, degreasers, corrosion inhibitors, or the like. The abrasive article may oscillate at the abrading interface during use. In some instances, this oscillation may result in a finer surface on the workpiece being abraded.
The brush as disclosed herein can be used by hand or used in combination with a machine to refine a surface by: cleaning a workpiece surface, including removing paint or other coatings, gasket material, corrosion, or other foreign material. At least one or both of the brush and the workpiece can be moved relative to the other. The abrasive article or brush can be converted into a belt, tape rolls, disc, sheet, and the like. Typically brush discs can be secured to a back-up pad by an attachment means. These brush discs can rotate between about 100 to 30,000 revolutions per minute, typically between about 500 to 20,000 revolutions per minute.
An abrasive brush as disclosed herein can be used to deburr a substrate. Methods of deburring a substrate generally include contacting the substrate with at least one bristle of an abrasive brush as described herein in a contact region; and inducing relative motion between the substrate and the at least one bristle. A method of deburring can also optionally include applying a lubricant adjacent the contact region.
An abrasive brush as disclosed herein can also be used to refine a surface of a substrate. Methods of refining the surface of a substrate generally include contacting the substrate with at least one bristle of an abrasive brush as described herein in a contact region; and inducing relative motion between the substrate and the at least one bristle, wherein the efficiency exceeds about 1.0.
In general, abrasive brushes, and methods of using abrasive brushes can have associated brush efficiency or efficiencies, respectively. For example, a method of abrading a substrate can have an associated efficiency, and a method of refining a surface of a substrate can have an associated efficiency. Brush efficiency, or the efficiency of a method of using a brush (to deburr a substrate or to refine a surface of a substrate, for example) is generally the ratio of the mass of the substrate cut or abraded by the brush in a time interval (for example, grams of substrate) to the mass of the brush that is worn in that same time interval (for example, grams of the brush). The amount of the brush that is worn can be calculated by taking the difference in the brush weight before and after the substrate is worked upon. In an embodiment, a brush efficiency or an efficiency of a method of abrading a substrate, or refining a surface of a substrate can have an efficiency that is at least about 1 or greater. Greater magnitudes of brush efficiency imply better brush performance.
In general, an abrasive filament as described herein can be made by (a) rendering a thermoplastic matrix molten and combining abrasive particles therewith; (b) extruding the molten thermoplastic matrix and abrasive particles; and (c) cooling the composition to a temperature sufficient to harden the molten thermoplastic matrix and thus form a hardened composition comprising a thermoplastic matrix having abrasive particles interspersed throughout.
Methods of making abrasive filaments with sheaths and cores include those disclosed is U.S. Pat. No. 6,352,471 (Bange et al.), the disclosure of which is incorporated herein by reference, and U.S. Pat. No. 5,460,885, Barber et al., and U.S. Pat. No. 5,427,595, Pihl et al., already incorporated by reference. The methods and apparatuses for forming such filaments as given therein can advantageously be modified as is within the knowledge of those skilled in the art to extrude monofilament embodiments as disclosed herein.
Abrasive filaments may also be made using unitary injection molding. Such a method comprises the steps of: a) mixing a thermoplastic matrix and plastic abrasive particles together to form a mixture; b) heating the mixture to form a flowable material; and c) injecting the flowable material under pressure into a mold to form an abrasive brush, wherein the brush comprises a securing element, such as a generally planar flexible base or center portion, and a plurality of bristles extending from the base or center portion, wherein the bristles are integrally molded with the base.
Generally a single screw or a twin screw extruder can be utilized. In addition, a CTM (cavity transfer mixer) can also be used. These extruders are known in the art of thermoplastic extrusion. Temperatures, material feed rates, hoppers, and the like are also known.
The abrasive particles can be mixed with the thermoplastic while the thermoplastic is either in the molten or solid state. A single stream of polymer/plastic can be used to produce filaments as disclosed herein. In an alternate method, two individual feed streams can be used.
Abrasive particles may be added to the molten thermoplastic matrix through a feed port in the extruder into the molten thermoplastic matrix mass. In an embodiment, they can be added at a point early enough to afford adequate dispersal of abrasive particles throughout the molten thermoplastic matrix. Alternatively, abrasive particles may be distributed in the molten thermoplastic matrix coating via a second step (i.e. after the preformed core has been coated with molten thermoplastic matrix), such as by electrostatic coating.
Abrasive filaments as disclosed herein including a thermoplastic matrix and abrasive particles can be extruded into cross-sectional shapes such as circles, ovals, and ellipses, polygons such as, for example, squares, rectangles, hexagons, and trapezoids, stars, and any other shape.
A cold water quench can be located immediately downstream of the die through which the molten extruded or coextruded filament or the thermoplastic matrix coated preformed core passes to achieve rapid cooling of the molten thermoplastic matrix to form a hardened composition comprising thermoplastic matrix and abrasive particles.
The abrasive filament may then be cut into individual abrasive filaments having the desired length. Although it is within the scope of this disclosure to orient the filaments to increase their tensile strength prior to use, it is not necessary to do so.
After the molten, abrasive filament has hardened, the filaments may have a coating (e.g. a plastic coating) applied there over. It is also within the scope of this disclosure to have the abrasive particles protrude out of the filament.
Disclosed herein is a method of deburring a substrate having at least one burr, with a brush, the brush comprising bristles comprising eutectic alumina zirconia particles and a matrix of thermoplastic polymer, wherein the method comprises the steps of: contacting the substrate with at least one bristle of the brush in a contact region; and inducing relative motion between the substrate and the at least one bristle.
Also disclosed herein is the method discussed in the preceding paragraph, wherein the eutectic alumina zirconia particles comprise from about 50 to 60 percent by weight of alumina. Also disclosed herein is the method discussed in the preceding paragraph, wherein the eutectic alumina zirconia particles comprise from about 52 to 56 percent by weight of alumina. Also disclosed herein is the method discussed in the preceding paragraph, wherein the eutectic alumina zirconia particles comprise from about 38 to 43 percent by weight of zirconia. Also disclosed herein is the method discussed in the preceding paragraph, wherein the abrasive particles are substantially uniformly interspersed throughout said filament. Also disclosed herein is the method discussed in the preceding paragraph, wherein the abrasive filament comprises about 10 percent to 90 percent by weight of thermoplastic polymer; and about 10 percent to 90 percent by weight of eutectic alumina zirconia particles. Also disclosed herein is the method discussed in the preceding paragraph, wherein the abrasive filament comprises about 50 percent to 80 percent by weight of thermoplastic polymer; and about 20 percent to 50 percent by weight of eutectic alumina zirconia particles. Also disclosed herein is the method discussed in the preceding paragraph, wherein the securing element comprises a cylindrical hub, and wherein said filaments are bonded to said hub.
Disclosed herein is a method of refining the surface of a substrate with a brush, the brush comprising bristles comprising eutectic alumina zirconia particles and a matrix of thermoplastic polymer, wherein the method comprises the steps of: contacting the substrate with at least one bristle of the brush in a contact region; and inducing relative motion between the substrate and the at least one bristle, wherein the efficiency is at least about 1.0.
Also disclosed herein is the method discussed in the preceding paragraph, wherein the eutectic alumina zirconia particles comprise from about 50 to about 60 percent by weight of alumina. Also disclosed herein is the method discussed in the preceding paragraph, wherein the eutectic alumina zirconia particles comprise from about 52 to about 56 percent by weight of alumina. Also disclosed herein is the method discussed in the preceding paragraph, wherein the eutectic alumina zirconia particles comprise from about 38 to 43 percent by weight of zirconia. Also disclosed herein is the method discussed in the preceding paragraph, wherein the abrasive filament comprises about 10 percent to about 90 percent by weight of thermoplastic polymer; and about 10 percent to about 90 percent by weight of eutectic alumina zirconia particles. Also disclosed herein is the method discussed in the preceding paragraph, wherein the abrasive filament comprises about 50 percent to about 80 percent by weight of thermoplastic polymer; and about 20 percent to about 50 percent by weight of eutectic alumina zirconia particles. Also disclosed herein is the method discussed in the preceding paragraph, wherein the securing element comprises a cylindrical hub, and wherein said filaments are bonded to said hub.
Disclosed herein is an abrasive filament comprising: a matrix of thermoplastic polymer; and a plurality of eutectic alumina zirconia particles interspersed throughout at least a portion of the matrix, wherein the efficiency of abrading a workpiece is at least about 1.0.
Also disclosed herein is the abrasive filament discussed in the preceding paragraph, wherein said matrix of thermoplastic polymer comprises a polymer selected from polyamide and thermoplastic elastomer. Also disclosed herein is the abrasive filament discussed in the preceding paragraph, wherein the eutectic alumina zirconia particles comprise from about 50 to about 60 percent by weight of alumina. Also disclosed herein is the abrasive filament discussed in the preceding paragraph, wherein the eutectic alumina zirconia particles comprise from about 52 to about 56 percent by weight of alumina. Also disclosed herein is the abrasive filament discussed in the preceding paragraph, wherein the eutectic alumina zirconia particles comprise from about 35 to 45 percent by weight of zirconia. Also disclosed herein is the abrasive filament discussed in the preceding paragraph, wherein the eutectic alumina zirconia particles comprise from about 38 to 43 percent by weight of zirconia. Also disclosed herein is the abrasive filament discussed in the preceding paragraph, wherein said abrasive filament comprises about 10 percent to about 90 percent by weight of thermoplastic polymer; and about 10 percent to about 90 percent by weight of eutectic alumina zirconia particles. Also disclosed herein is the abrasive filament discussed in the preceding paragraph, wherein said abrasive filament comprises about 50 percent to about 80 percent by weight of thermoplastic polymer; and about 20 percent to about 50 percent by weight of eutectic alumina zirconia particles. Also disclosed herein is the abrasive filament discussed in the preceding paragraph, wherein said abrasive filament comprises about 55 percent to about 75 percent by weight of thermoplastic polymer; and about 25 percent to about 45 percent by weight of eutectic alumina zirconia particles. Also disclosed herein is the abrasive filament discussed in the preceding paragraph, wherein said abrasive particles are substantially uniformly interspersed throughout said filament.
Disclosed herein is an abrasive brush comprising: a plurality of abrasive filaments, said filaments comprising a matrix of thermoplastic polymer and a plurality of eutectic alumina zirconia particles interspersed throughout at least a portion of said matrix; and a securing element that functions to secure the plurality of abrasive filaments to form a brush, wherein the abrading efficiency on a workpiece is at least about 1.0.
Also disclosed herein is the abrasive brush discussed in the preceding paragraph, wherein the eutectic alumina zirconia particles comprise from about 50 to about 60 percent by weight of alumina. Also disclosed herein is the abrasive brush discussed in the preceding paragraph, wherein the eutectic alumina zirconia particles comprise from about 52 to about 56 percent by weight of alumina. Also disclosed herein is the abrasive brush discussed in the preceding paragraph, wherein the eutectic alumina zirconia particles comprise from about 38 to 43 percent by weight of zirconia. Also disclosed herein is the abrasive brush discussed in the preceding paragraph, wherein said abrasive filament comprises about 10 percent to about 90 percent by weight of thermoplastic polymer; and about 10 percent to about 90 percent by weight of eutectic alumina zirconia particles. Also disclosed herein is the abrasive brush discussed in the preceding paragraph, wherein said abrasive filament comprises about 50 percent to about 80 percent by weight of thermoplastic polymer; and about 20 percent to about 50 percent by weight of eutectic alumina zirconia particles. Also disclosed herein is the abrasive brush discussed in the preceding paragraph, comprising a plurality of abrasive filaments as discussed above. Also disclosed herein is the abrasive brush discussed in the preceding paragraph further comprising a securing element that functions to secure the plurality of abrasive filaments to form a brush. Also disclosed herein is the abrasive brush discussed in the preceding paragraph, wherein said securing element comprises a cylindrical hub, and wherein said abrasive filaments are bonded to said hub.
The disclosure will now be further added to with reference to the following examples. These examples demonstrate various specific embodiments and are not intended to limit the scope of this disclosure.
Abrasive filled filaments were made using a Werner-Pfleider twin screw extruder. The filaments were nominally 0.71 mm (0.028 inch) diameter and used polyamide (“ZYTEL 158 NC010” nylon 6,12 resin (E.I. DuPont de Nemours & Co., Wilmington, Del.) or a compound of thermoplastic elastomer “HYTREL 6356 polyester TPE resin (E.I. DuPont de Nemours & Co., Wilmington, Del.) and lubricant “MB50-010” (MultiBase, Copley, Ohio) as the matrix. Pellets of Hytrel 6356 and MB50-010 were mechanically mixed to attain a homogeneous mixture; this mixture was fed into the feed port of the extruder. The abrasive mineral was introduced into the molten polymer via a vent port in the extruder using a gravimetric feeder to maintain correct resin:mineral weight ratios. In order to achieve similar volume ratios of mineral to thermoplastic matrix, mineral addition weights were adjusted to accommodate differences in density between aluminum oxide and silicon carbide and alumina-zirconia eutectic mineral. The filaments that were made are shown below in Table 1.
The filaments were converted into 8 inch nominal OD×2 inch ID×1 inch wide (20.32×5.08×2.54 cm) brushes (Tanis Inc., Delafield, Wis.). The brushes were made with nominal 2.54 and 5.08 cm (1 inch and 2 inch) trim lengths. A constant fiber density was maintained between brushes of the same trim length. A single brush was constructed with each filament type.
Tests were conducted by running the brushes at 1750 rpm and placing them in contact with a test substrate for 150 seconds, followed by cooling for 30 seconds, and repeating for two more cycles under a load of 22.24 N (5 lbf). The test substrate was moved at a speed of 7.62 cm/sec (3 inch/second) up and down over a distance of 17.78 cm (7 inches) during the test. Brush cut and wear were calculated as the change in test substrate weight and brush weight before and after the test, respectively. The performance of the brushes was measured by “brush efficiency”, which was calculated by determining the mass of substrate abraded away by the brush in a time interval divided by the mass of the brush lost in that same time interval. Greater magnitudes of brush efficiency connote better brush performance.
The 2 inch (5.08 cm) trim brushes were run against the burr side of perforated cold roll steel plate to replicate deburring operations (
As seen in
A test “run” was conducted by running the brushes at 1750 rpm and placing them in contact with a test substrate (carbon steel or aluminum) for 150 seconds, followed by cooling for 30 seconds, and repeating for two more cycles under a load of 22.24 N (5 lbf). The test substrate was moved at a speed of 7.62 cm/sec (3 inch/second) up and down over a distance of 17.78 cm (7 inches) during the test. Brush cut was calculated as the change in test substrate weight before and after the test. The test run was repeated consecutively four more times.
2.54 cm (1 inch) trim brushes (manufactured as in Example 1) were run against a 1008 cold rolled steel plate (
Filaments were converted into brushes for testing as discussed in Example 1. Test brushes were mounted on an arbor with a means for rotating them to 1750 rpm. The burr side (the perforating die exit side) of a metal workpiece consisting of a 50 mm×280 mm piece of 16 gauge (1.5189 mm thick) 1008 CRS perforated screen (4 mm diameter staggered holes, 46% open, stock pattern number 041, commercially available from Harrington & King Perforating Company, Chicago, Ill.) was urged against the rotating brush in each case with a force of 22.2 N. The test metal perforated screen was moved up at the rate of 76 mm/second traversing a stroke of 178 mm. At the end of the stroke, the perforated screen was separated from the brush, moved back to its original position, and re-engaged with the brush for another stroke. This was repeated for a total of 3 strokes. The perforated screen was rotated 180 degrees in-plane (to simulate a “downstroke”) and another 3 strokes were completed, thereby providing a test specimen that had been deburred 3 upstrokes and 3 downstrokes (3U3D). Two additional perforated screens were deburred with each test brush, one 6U6D and the other 8U8D.
The height of residual burrs following deburring was measured on a centrally-disposed hole in each test screen by vertical scanning interferometry using a WYCO NT9800 Optical Profiling System (Veeco Instruments Inc., Woodbury, N.Y.) set at 2% modulation threshold with a 10× objective and a 0.5× transfer lens producing a unified image via stitching mode. Measurements were made at eight locations spaced at 45 degrees around each hole. The results are shown in Table 2 below and graphically in
Thus, embodiments of extruded abrasive filaments and brushes formed thereby are disclosed. One skilled in the art will appreciate that the subject matter of this disclosure can be practiced with embodiments other than those disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation, and this disclosure is limited only by the claims that follow.
This application claims the benefit of priority to U.S. Provisional Application No. 60/917,172, entitled “EXTRUDED ABRASIVE FILAMENT AND BRUSH” filed on May 10, 2007, the disclosure of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60917172 | May 2007 | US |
