MXPA94006550A - Cutting with jet current abras - Google Patents

Abstract

The present invention relates to the method of machining and cutting with abrasive jet stream, wherein a plurality of abrasive particles are suspended in a jet medium that can flow and projected at high speed and pressure in a workpiece, the improvement comprises: A. forming said medium of a polymer having sacrificial sacrificial chemical bonds, which preferably break under conditions of high shear during cutting and machining, said chemical bonds are selected from the group consisting of ionic bonds, aqueous hydrogel bonds promoted with a metal from group II to group VIII and non-aqueous intermolecular bonds; projecting the medium and the suspended abrasive in the work place to carry out the machining and cutting under conditions of shear stress, which preferably break the sacrificial sacrificial chemical bonds without substantial cleavage of the polymer chain; to reform the broken chemical bonds during the cutting and machining, and D. to recycle the medium and the abrasive to reuse in the method

Description

CUTTING WITH ABRASIVE JET CURRENT Mr. LAWRENCE J. RHOADES, of North American nationality, domiciled at 224 Maple Avenue, City of Pittsburgh, State of Pennsylvania, United States of America, inventor, assigns, sells and transfers to EXTRÜDE HONE CORPORATION, society American, domiciled at 8075 Pennsylvania Avenue, city of Irwin, State of Pennsylvania, United States of America, all rights to the invention described below: SUMMARY OF THE INVENTION Cutting with abrasive jet stream, wherein an abrasive is suspends in a continuous flow jet means (64) and is projected at high speed and pressure (75) into a workpiece (76), substantially improved upon forming the medium of a polymer having reformable sacrificial chemical bonds, which preferably break under high shear conditions. By projecting the medium and suspended abrasive, the sacrificial chemical sacrificial bonds are broken while cutting. The chemical bonds will be reformed, allowing recycling of the medium and abrasive for reuse in the method. The jet is effective at pressures of approximately 14 to 80 MPa. BACKGROUND OF THE INVENTION TECHNICAL FIELD The present invention relates to the field of cutting with jet stream and particularly to cutting with abrasive jet streams, wherein a suspension of abrasive particles in a fluid medium is pumped with high pressure and high speed against the surface of a workpiece to perform cutting operations. These operations are widely used to cut sheets and metal plates in the manufacture of useful articles. PREVIOUS TECHNIQUE Abrasive water jets have been developed to be widely used in cutting and machining operations, particularly with plates and metal sheets for quick and economical cutting and related forming operations. Known applications have been cutting materials that are difficult to machine, such as stainless steels, titanium, nickel alloys, reinforced polymeric compounds, ceramics, glass, rock and the like. These techniques are particularly advantageous to produce cutting action through highly localized action at a low average applied force to effect cutting of these materials with minimal stress or thermal deformation, without interruption of the crystalline structure and without releasing sheets of materials compounds To perform abrasive water jet cutting, a specialized nozzle assembly is used to direct a coherent collimated high pressure stream through a small diameter building to form a jet. Typically, pressures of approximately 200 MPa (approximately 30,000 psi) and above are applied to force the medium through the orifice of the nozzle. Typical nozzle assemblies are formed of abrasion resistant materials such as carbide or tungsten boride. The hole itself can be formed of diamond or sapphire. Abrasive particles are added to the high-velocity stream of water exiting the nozzle orifice, by directing the water stream through a "mixing tube" and introducing abrasive particles into the tube in the region between the outlet of the current of the orifice and its entrance to the "mixing tube" the mixing tube which is typically several centimeters in length, is a region of extremely turbulent flow contained, where the relatively stationary or slow moving abrasive particles are accelerated and remain trapped in the high-velocity water stream, which may have nozzle exit velocities as high as Mach 3. The entrainment process tends to disperse and decelerate the water stream while the abrasive particles collide with the pipe wall and between yes. Relatively wide chunks result from scattered current, energy is wasted and the tube wears out quickly, even when it is made from abrasion resistant materials, such as carbide or tungsten boride and the like. Some studies have shown that as much as 70% of the abrasive particles fracture before reaching the workpiece they are going to cut. In later developments, non-abrasive water jets have been thickened with water-soluble polymers, which help in obtaining and maintaining coherent jet streams by reducing the level of wetting, splashing and the like. Closer cuts can be achieved. The pressures and speeds of operation remain quite high. It is also known to suspend abrasives to particles in water jets, ordinarily based on the thickening effect of the water-soluble polymers to act as a suspending agent in the system. The abrasive cuts with greater efficiency than water alone or water with a thickening agent, but introduces a whole spectrum of difficulties. PROBLEMS IN THE TECHNIQUE Due to the high pressures and flow costs involved in the jet stream machining, it is quite difficult to maintain coherent streams of the jet. While the use of thickening agents provides significant improvements, these operations tend to be costly since neither the water nor the soluble polymer are reusable, because the high shear inherent in these operations degrades the polymer, - the degraded polymer remains dissolved in water, providing the waste expense of the waste.

When the abrasive is added to the system, for cutting and milling of stream with jet, the difficulties and expense are even greater. Nozzles used for abrasive waterjet cutting operations are more complex and require auxiliary equipment to add abrasive to the stream, usually adjacent immediately to the nozzle assembly or as part of that nozzle. The assembly includes a mixing chamber, where the abrasive is introduced into the medium, a focusing tube, where the current is accelerated and a small orifice where the flow collimates in a stream of coherent jet that is projected onto the piece of work. The mixing chamber and the associated tooling are complex, required by the need to inject the abrasive particles into the relatively high velocity stream. The mixing chamber is required to inject the particles into the circulating stream as much as possible to minimize the rate at which the interior surface from the mixing chamber and orifice becomes worn. Because the components have widely different densities, it has generally not been possible to premix the components before the nozzle assembly because even in thickened fluids, the abrasive particles tend to separate and settle at an appreciable rate. The additional thickening is not cost effective in these systems.

The uniform dispersion of the abrasive in the current h proved to be elusive and inconsistent, substantially attributable to the wide differences in density of the materials, the high velocity differences between the injected particles and the fast-flowing stream, and the resulting need that the current accelerates the abrasive particles The mixing of the particles in the medium is often incomplete and inconsistent, the acceleration requirements of the abrasive brakes the flow of medium and the incomplete mixing introduces inconsistencies and heterogeneities that cause divergent flows and trajectories different from the current or its components that leave the orifice, producing widths of inconsistent and / or increased sections and imprecise and non-uniform cutting edges of the workpiece. The mixing process causes the abrasive to produce high wear rates inside the nozzle elements that result in a useful life measured in operating hours under favorable conditions, and less favorable conditions can reduce the nozzle or hole life. matter of minutes. For example, the precise alignment of the nozzle and the focusing tube are quite critical. The entrainment of the particles also tends to make the jet stream divergent instead of coherent, resulting in wide stretches and extra time and effort in the cutting operation.

When the jet stream in which it is introduced and abrasive is adequately thickened, the shear degradation avoids the reuse of the medium and the cost is substantial. Considerable amounts of polymer are required to achieve adequate thickening to effectively suspend commonly used abrasives. Nozzle orifices for jet streams are typically in the order of approximately 0.25 m (approximately 0.010 in.). When an abrasive is introduced, the minimum practical mixing tube is approximately three times the diameter of the orifice, ie approximately 0.75 m (approximately 0.030 in) or greater. Smaller nozzles have an intolerably short service life with excessive erosion during operations. The wider nozzle produces a wider current cut, and requires more medium and abrasive consumption per cutting unit. Hollinger et al. "Precision Cutting With a Pressure, Coherent Abrasive Jet Suspension" (Precise Cutting with a Low Pressure Coherent Abrasive Suspension Jet) 5th American Water Jet Conference, Toronto, Canada, August 29-31, 1989, has reported improved dispersions of abrasives and aqueous solutions of methyl cellulose and a proprietary thickening agent "Super Water" (brand of Bar ely Chemical Co.). S work is based on reaching enough viscosities based on the use of 1.5 to 2 percent by weight of the thickeners to allow pre-mixing of the abrasive in the polymer solutions eliminating the need for injection of the abrasive in the Hollinger nozzle and collaborators reported that holes as small as 0.254 mm (0.01 in.) can be used effectively. The work of Hollinger and collaborators subsequently has been incorporated in the U.S. patent. No. 5,184.43 granted on February 9, 1993, in an application filed on August 29, 1990. The entanglement of the polymers used does not contemplate. See also Howells, "Polymerblasting with Super-Wat from 1974 to 1989: a Review" (Super-water polymer jet attack from 1974 to 1989: a review), Int'l J. Water J Technol. , Vol. 1, No. 1, March 1990, 16 pp. Particularly detailed Howells concerning the reasons why polymer stream stream media with or without abrasion have not been recycled and reused. See pages 8 and 9. In many aspects, the aqueous water-based systems employed in the prior art may not be employed with some particular materials and workpieces, where the presence of water or the corrosion they may produce can not be tolerated. The cut with jet stream has not been applied to this circumstance. In all the thickened systems based on polymers of the prior art, the degradation of polymer chains by high shear ratios applied in the system, to date has prevented effective techniques from recovering and reusing the jet stream medium, resulting in substantial waste management requirements and considerable expense for polymer and abrasive consumed. OBJECTIVES AND COMPENDIUM OF THE INVENTION An object of the present invention is to provide a means of machining and cutting with chor current that overcomes the problems encountered in the prior art. In particular, an object of the present invention is to provide premixed media with reusable polymer thickened chorus stream, which effectively suspends abrasive particles, forms stable coherent stream streams, cuts with high efficiency and with narrow cuts, and q is reusable, and in this way reduce waste management requirements and raw material costs. A further object of the present invention is to employ cutting with jet stream at lower pressures required flow volumes of the prior art. Another object of the invention is to allow the use of buildings of smaller diameter for the current grinding with an abrasive jet than that carried out in the prior art. Another objective is to allow cutting with abrasive jet stream using a simplified nozzle considerably smaller and particularly shorter than those required to date for cutting and machining with conventional abrasive water stream. Still another objective is the provision of a cutting system with low cost jet stream, based on the recirculation and reuse of thickened jet stream medium. In an embodiment of the present invention, an object of the present invention is to provide a non-aqueous jet stream medium, which allows the use of machining operations and jet stream cutting with materials and workpieces not previously usable with cutting operations with jet stream. These and still other objectives that become apparent from the following description are achieved by forming a jet stream medium of a polymer having sacrificial sacrificial chemical bonds, which preferably break and disrupt during processing and cutting under high shear conditions., and then reformed to reconstitute the medium in a convenient way to recirculate to the process and reuse. In one embodiment of the invention, the water jet stream is thickened with an ionically entangled water-soluble polymer, wherein the ionic entanglements are formed by metal salts of Groups II to VIII of the Periodic Table. In a second embodiment, the aqueous jet is formed of a hydrogel of a water soluble polymer, preferably entangled with a gel-promoting water soluble salt of a metal of groups I to VIII of the Periodic Table. The entanglement in these systems is based on intermolecular bonds, ie hydrogen bonds, between polymer molecules. In a third embodiment, a non-aqueous medium d is formed by an intermolecular interlacing polymer which in itself forms a predominant constituent of the jet stream. In operation, the polymer suspends the abrasive particles. The polymer can be partially decomposed under the shear forces of the operation by interrupting the intermolecular bonds that produce the polymer entanglements. After the jet performs its work on the work piece, the polymer is collected, the interlacing bonds are allowed to reform and the medium is recycled for reuse in the process. Smaller orifice diameters in the small order as approximately 0.1 mm (approximately 0.004 in.) Can be effectively employed if the abrasive particle diameter is sufficiently small. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic cross sectional view of an embodiment of this invention that provides recirculated media for reuse; Figure 2 is a cross-sectional view of a preferred form of nozzle according to the present invention. DETAILED DESCRIPTION The present invention is based primarily on the observation that the shear stresses imposed in the formation and use of jet streams containing polymer used for cutting operations with jet stream, so necessarily high. While a step amount can be made to minimize the shear stresses applied in the nozzle assembly, the impact forces of the jet stream on the work surface are also high and also break the polymer structure. Since high shear is an inherent characteristic of the cutting operation, techniques to reduce polymer decomposition at a certain point are incompatible with the requirements of the operation of cort itself and thus are limited. The inclusion of one and a half or two weight percent of thickener or polymer material in the jet stream medium typically employed in the prior art, in this manner is a very substantial proportion of the cost of the operation. The time and energy requirements for dissolving the polymer in the aqueous medium are also a substantial factor in operating costs and may, if not properly planned, impose substantial operational delays due to the significant time required to dissolve these polymers.

If it is not controlled consistently, variations in the solution can introduce a lack of uniformity in the operations of cutting and machining and deteriorate the quality of the result. After use, the degraded polymer solution is a substantial handling and collection charge in the operation, and there are no known uses for the resulting waste material. The costs of handling and disposal are typically a significant cost of operations. In this context, the use of more complex polymers more expensive to achieve certain specific benefits to the operation, is generally displaced by the added costs. The degradation of polymers in co-current jet cutting systems is produced by breaking the chemical bonds that constitute the polymer and particularly the chemical bonds that form the main structure of the polymer chain. The result of these effects is to reduce the molecular weight of the polymer and a consequent reduction of viscosity and loss of the capacity of the medium to effectively suspend the abrasive particles, to form a coherent jet stream and limit the abrasive erosion of the equipment. In the present invention, these difficulties are overcome by the use of polymeric materials that have the ability to reform the broken chemical bonds during the cutting operation with jet stream and thus can be reconstituted in a fully effective way to allow recycling and reuse . In this way while the chemical bonds will break during the cutting operations, under the influence of high shear in the nozzle and by the impact to the workpiece, these effects are no longer destructive to the utility of the current medium. jet. In practice, the polymers used in the present invention can be recycled by operation for many operating cycles. With time, there will be a more severe degradation of the chains of the main polymer structure (usually covalent bonds) that will limit the number of cycles. In general, the preferred polymers of the present invention can be recycled through the system for 20 to 100 cycles or more before replacement is required. The reforming of the broken links to replenish the polymer thickener in a useful manner requires that the polymer contain bonds that are sacrificed under high shear and high impact conditions of the cutting operation, and that will reform to reconstitute the original polymer structure. This requires that the polymer contains an adequate population of chemical bonds other than covalent bonds. When covalent bonds are broken, the fragments are so highly reactive that broken chains are usually terminated by chain termination reactions very close to snapshots and the original bonds can not be reformed.

There are three types of chemical bonds that to date have been evaluated in the present invention and that have proven to be effective. These are ionic bonds, intermolecular hydrogen bonds and B: 0 intermolecular bonds. Ionic bonds are frequently used as ionic entanglement of a variety of polymer. These polymers are often well-water soluble types for use in the present invention. When these polymers are ionically crosslinked, they typically form gels swollen with water, having effective viscosity levels for effecting highly durable suspensions of the high density abrasive particles added in the process of the present invention. In ionically entangled hydrogels, the ionic bonds are weaker than the covalent bonds of the polymer backbone and are the ionic bonds which are preferably interrupted and broken under exposure to high shear stresses. The ionic species produced when the bonds are broken are relatively stable and in the context of the polymer systems used here they will react only to restore the interrupted interlacing., and in this way restore the high viscosity hydrogel structure, once the high shear stress is removed. In an alternate embodiment, gel-forming water-soluble polymers are formed in hydrogels, with or without gel promoters, such as water-soluble salts of metals of Groups III to VIII of the Periodic Table. Hydrogels are based on the formation of intermolecular bonds, ie hydrogen bonds, between the polymer molecules. These bonds are weaker than the ionic bonds and in the context of the present invention, they facilitate the thinning of the medium under high shear stresses imposed in the formation of jet cutting and provide the sacrificial bonds that protect the covalent bonds in the polymer and minimize chain break. These hydrogels also serve to promote high viscosity at rest, where the intermolecular bonds are formed in the constitution of the gel or reform after use, which is highly convenient to avoid sedimentation of the abrasive particles. While a number of water soluble polymers have been employed in preparing jet stream cutting formulations, including some gel-forming polymers, they have been employed without gelation promoters and at concentrations in which spontaneous gelation does not occur. The addition of these polymers in the prior art has focused primarily on increasing the coherence of the jet. Without the formation of a substantial population of sacrificial bonds, the polymer is significantly degraded in a single use and is not reusable. The jet formulations of the prior art are normally discarded as waste.

Non-aqueous polymer formulations are also possible where the polymer is entangled by other types of sacrificial intermolecular bonds. These formulations are particularly significant to cutting and machining materials, which are vulnerable to water, such as ferrous metals and the like. A preferred non-aqueous polymer, interlaced by intermolecular bonds, comprises the poly-borosiloxane family. These polymers are intertwined by sharing pairs of electrons between tertiary B atoms in the polymer chain with 0 atoms in the chain of adjacent polymer molecules. The specific properties of meaning for the present invention can be controlled very well directly and in fine form including molecular weight of the polybromosiloxane and the like. The formulation of the cutting media based on the use of polyborosiloxanes, as described in more detail below, is particularly preferred in the present invention, due to the non-aqueous nature of the medium, the close degree of viscosity control, and the ability to compensate viscosity at rest and reduced viscosity with high shear, to adjust to the requirements of the cutting and machining operations to be performed. Intermolecular bonds, whether based on hydrogen bonds or B: 0 bonds, are also weaker than covalent bonds and polymers that readily form intermolecular bonds are used, particularly in non-aqueous jet stream processing in the present invention. Under the high shear conditions involved in the production of the jet stream and under the impact forces on the workpiece surfaces, the intermolecular bonds will break, preferably absorbing a portion of the energy imposed on the polymer and retaining the bonds covalent that constitute the main structure of the polymer. These intermolecular bonds will easily reform over time once the high shear stress is removed, restoring the interlaced structure and the high gel-like viscosity required of the system. In the context of the present invention, the entanglement links, i.e. ionic or intermolecular bonds, are those that first break under the high shear and high impact conditions of the operation, and in this way are sacrificed to absorb the applied energy . They are in that sense sacrificial links that serve to protect the covalent bonds against the degradation that would otherwise break the polymer chains in an irreversible and permanent way, characteristic of the polymer degradation of the materials and processes of the prior art. The broken bonds will spontaneously reform when the shear stresses are removed, for example when the medium is allowed to settle. The basis for the ionic bonds remain intact, as is the characteristic of the ionic species of the formation of these bonds in the original polymer medium that occurs when breaking the bonds during operation of the cutting process with jet stream. These bonds are reversibly formed in the first case, and exist in a state of equilibrium in aqueous medium in any case. The speed of reforming the bonds is dictated predominantly by the mobility of the polymer chains in the used and degraded medium. At the reduced viscosity of the medium under these conditions, mobility is relatively substantial and the gel will typically reform within a few minutes of collection. Accordingly, it is convenient to allow the mixing of the collected polymer and abrasive solution to ensure the substantially homogeneous dispersion of the abrasive particles in the hydrogel, although it is also possible to redisperse the abrasive in the reformed gel after they are fully restored. the ionic bonds. The thinning of the polymer component in response to the high shear applied, in itself is of benefit for the formation of abrasive jet stream, since the formulation will show reduced viscosity in the jet stream, so that the applied energy is imparted in higher proportion to abrasive particles, improving their cutting effectiveness. The polymer acts to produce a highly coherent jet stream and serves to minimize abrasion within the equipment.

These are the specific viscosity changes and parameters that allow the simplification of the equipment requirements with respect to the abrasive water jet stream techniques of the prior art. Because entrainment of the abrasive in the medium occurs upon constitution in the usual mixing equipment employed, there is no need to provide a separate supply of the abrasive to the nozzle, feed the abrasive particles into the stream or provide a mixing tube, all of which is normally required in the prior art. Broken intermolecular bonds, spontaneously and rapidly will be reformed and it is quite simple to effect a redispersion of the abrasive if in fact it is required. As the polymer systems are recycled through the jet stream cutting process and the reformation of broken chemical bonds, there will be some breakage of covalent bonds in each cycle. Although the proportion of broken bonds irreversibly in each individual cycle will be modest, the effect is cumulative, and after a substantial number of cycles, the permanent degradation of the polymer will become significant. As the polymer degrades in a cumulative and irreversible manner, the viscosity of the reformed polymer will gradually decline, and the medium will eventually begin to exhibit an undesirable degree of tack. In the efforts to date, the polymer thickeners employed in the water jet stream cutting operations of the present invention can be successfully recycled for up to as many as 100 cycles of use before replacement is required. The non-aqueous media of the present invention are at least as durable, and often considerably more durable than aqueous systems. The number of cycles will vary, of course with the particular polymer, the process conditions and the like, but it is quite apparent that the medium of the present invention has contributed a significant degree of recycling compared to the prior art and does not support the reuse of the medium after a single step through the hole. In general, it is convenient to periodically or even continuously add small amounts of "fresh" polymer-abrasive mixture to maintain material consistency and uniformity during use. Equivalent increments of material are conveniently removed to maintain a relatively constant volume of media in the equipment. Ionically suitable crosslinkable polymers for use in the present invention include any of the water soluble polymers that form gels ionically crosslinked with metal salts, metal oxides or organic gelation agents of metals of groups II to VIII of metals. Preferred species are those water soluble polymers having substantial proportions of hydroxyl groups. The polymers may also contain active ionizable reactive groups, such as carboxyl groups, sulfonic acid groups, amine groups and the like. Ionic interlacing polymers and interlacing systems are similar to hydrogels formed by intermolecular hydrogen bonds, except that ionic bonds only form under conditions that promote the ionization of entanglement species. These conditions may require control of pH, presence of promoters or reaction catalysts, such as Lewi acids or Lewis bases and the like. The formation of these ionically interlaced polymers is generally well known and characterized in the chemical literature, as they will understand that with ordinary skill in the art. A substantial amount of hydrogellable polymers and gelling agents is known, and substantially all those available can be used successfully in the present invention. Examples of water-soluble polymers containing preferred hydroxyl groups include, but are not limited to, guar gum, xanthan gum, hydroxypropyl hydroxyethyl derivatives of guar gum and / or xanthan gum, and gums containing or are substituted with related hydroxyl groups, hydroxymethyl cellulose, hydroxyethyl cellulose and related water soluble cell derivatives, synthetic polymers containing hydroxyl groups such as hydroxyl methacrylate , hydroxypropylmethacrylate and other water soluble polymers, such as polyacrylamide and the like. Also of interest are water-soluble species terminated in hydroxyl groups of oligomers and low molecular weight polymers, such as polyethylene oxide, polyoxymethylene and the like. Among the preferred gelling promoters of metals of group II to group VIII, which may be employed, are boric acid, sodium borate, and organic compounds of titanium, aluminum, chromium, zinc, zirconium metals and the like. A particularly preferred species for the modest cost requirements is a gelled solution of sodium borate of about 2 to 2.5 weight percent of guar gum in water. This particularly economical hydrogel has demonstrated ability to survive up to 12 cycles of cutting operations with jet stream at 14 MPa, followed by gel reformation without detectable permanent degradation of the polymer gel. A polymer bonded by non-aqueous intermolecular bond is obtained by a polybrosiloxane polymer composition, a hydrocarbon oil or fat extender or diluent and a plasticizer such as stearic acid or the like, having an effective jet stream viscosity. Polybromosiloxane polymers as a class are strong intermolecular binding species and when conveniently plasticized at viscosities suitable for jet formation, they are excellent jet stream media for water sensitive applications. In addition, polybromosiloxane formulations in general are generally non-tacky materials, which are easily removed from the workpiece surface after the cutting operation is completed. The borosiloxane polymers for use in the present invention will generally have molecular weights of about 200,000 and up to about 750,000, preferably about 350,000 to about 500,000. L atomic ratio B: If preferably it is in the range from about 1: 3 to about 1: 100, preferably about 1:10 to about 1:50. Borosiloxanes are highly compatible with a wide variety of fillers, softeners and plasticizers. It is common to use inert fillers as diluents to reduce material costs and to employ suitable plasticizers and softeners to further dilute the polymer and control the viscosity. In the present invention, abrasive particles will ordinarily be the only inert filler, although other fillers may be employed if the amount of abrasive is correspondingly reduced. As noted above, the abrasive (and other filler, if employed) may be in the range of about 5 to about 60 weight percent of the formulation, while in general about 25 to 40 weight percent is preferred.

Plasticizers and softening diluents are used to regulate the viscosity of the abrasive jet medium. Suitable plasticizers for use in silicone polymers are quite numerous and well known in the art and the selection of convenient viscosity controls is not narrowly significant for the present invention. Suitable materials include, by way of example and not by limitation, fatty acids of about 8 to 30 carbon atoms, in particular about 12 to 20 carbon atoms, such as palmitic acid, stearic acid and oleic acid; paraffinic hydrocarbon oils, particularly light oils such as "" primary distillation oil "(top oil) and other petroleum distillates and by-products, vegetable oils and partially or totally hydrogenated vegetable oils such as rapeseed oil, saffron or safflower oil, soybean oil and the like, hydrocarbon-based fats such as automotive lubricating greases and the like, mono-, di- and tri-esters of polyfunctional carboxylic acids such as dioctyl phthalate (DOP) and the like .. Liquid or semi-solid silicone oils also They can be used, and can impart considerable benefits, despite their cost, when the medium will be subjected to high temperatures and / or oxidizing conditions that can degrade hydrocarbon-based thinners and plasticizers.As mentioned, plasticizers and softening softeners are added to control the viscosity of the formulation, a resting viscosity typically 300 , 000 cps approximated to ambient conditions, as measured by a Brookfield viscometer, is adequate and convenient. As is well known, borosiloxane polymers exhibit a substantially apparent increase in viscosity, in response to applied shear, and even exhibit plug flow by flow paths configured at high shear. While there is no technique available for direct measurement of the viscosity in the nozzle of the present invention, we have found that formulations with resting viscosities of about 200,000 cps to about 500,000 cps are generally adequate and a viscosity of about 300,000 is quite reliable. We have calculated the effective viscosity as a function of the applied pressure and resulting jet stream volumes and consider that the effective specific viscosity at the nozzle is in the order of about 5,000 poise to about 20,000 poise. When the jet stream material is collected and allowed to settle, the viscosity quickly returns to the substantially original resting viscosity, typically in five minutes or less, even in one minute. We consider that the return to the original viscosity demonstrates the reformation of the intramolecular B: Si bonds and the relatively insignificant level of chain rupture. While there will be some degradation in a number of usage cycles, the level does not become significant until typically 20 or more cycles, and it may not be noticeable until 100 or more cycles of use have occurred. The long-term degradation is easily displaced by the periodic or continuous addition of unused fresh medium and removing an equivalent amount of half spent. This procedure also serves to replace abraded abrasive particles with new cutting particles and limit the accumulation of cutting or machining debris in the middle. In the present invention, injection of the abrasive into the nozzle is not preferred and is generally not desired. It is preferred that the abrasive particles be mixed in the gelled polymer in a separate pre-operation, and injected by a convenient high-pressure pump to the nozzle. In aqueous hydrogel systems, the polymer and gelling agent will typically be in the order of from about 1 to about 20 weight percent of medium, more often about 2 to 5 percent., typically for most polymers about 2 3 percent. The exact proportions can be optimized for any particular gel in relation to the particular abrasive its particle size and density and the proportion to be added. The abrasive will most often have a particle size from as low as about 2 micrometers to about 1400-1600 micrometers (about 16 mesh). Most commonly, the abrasive grain size will be in the gamma from about 20 to about 200 micrometers, preferably about 20 to about 80 microns. The jet stream medium may contain from about 1 to about 75 weight percent abrasive. More often, about 5 to about 50 weight percent and preferably about 15 to about 30 weight percent, is preferred. In operation, the formulations are employed in a manner that differs in a number of cutting aspects with jet stream as practiced in the prior art and as is familiar to those with ordinary skill in the art. In the context of the present invention, the polymer formulation is sensitive to viscosity at two different rates. First, the polymer must provide sufficient viscosity to effectively suspend the abrasive particles in the formulation, under low shear conditions, a parameter more closely defined by static viscosity. In addition, the formation of the jet stream under high shear conditions can substantially affect the coherence of the jet and the homogeneity of the dispersion of abrasive particles in the jet. These parameters are defined by dynamic viscosity. Although the polymer solutions are not Newtonian, it exhibits a fluid behavior that approaches Newtonian fluids under static conditions. In addition, newtonian fluid flow characteristics again predominate at high shear conditions. The time for a spherical particle to sediment at a certain height under the force of gravity in a static fluid, requires a particular time. In this way, by fluid mechanics, t = 18? H a2 [Dp - DL] g where: t = Time? = Fluid Viscosity H = Sedimentation Height a = Particle Diameter Dp = Particle Density DL = Fluid Density g = Acceleration of Gravity We have observed that the following considerations, which the previous formula depends on, are sufficiently valid for the purposes of the present invention: Laminar flow: At very low speeds, the characteristic of sedimentation of abrasive particles, flow characteristics are laminar or very close. Newtonian Fluid: Under near static conditions involved in particle sedimentation, the polymer formulations are sufficiently fluid in character, so substantially Newtonian flow characteristics are exhibited. Size of spherical particles: The irregular shape of abrasive particles introduces some error, but because the average particle size does not vary widely in its major and minor dimensions, and because in a substantial amount of particles these variations are averaged , the variation can be safely ignored in the present context. Formulations suitable for use in the present invention will have low viscosity of shear ratio (Brookfield) in the order of approximately 200,000 to 500,000, preferably 300,000 centipoise (cp). A 320 mesh SiC particle with a specific gravity of 3 will give a settling rate of 6.8 x 106 seconds per 2.54 cm (1 inch) (approximately 11 weeks, and suitable for the present invention). At higher shear ratios, the behavior of polymer formulations becomes non-Newtonian, where the viscosity depends on the ratio needed in a power-law relationship. This dependence is maintained until at a high proportion of shear, when the viscosity again becomes substantially independent of the applied shear and substantially again newtonian flow characteristics are applied.

One of the particular virtues of the jet stream formulations of the present invention is the reduction in pressure required in the jet formation to produce effective cutting effects. Typically, the pressures required will be in the order of about 14 to about 80 MPa (about 2,000 to about 12,000 psi), compared to typical pressures of at least 200 MPa (30.00 psi) and higher in the prior art. As a convention, the pressure used is inhibited as the pressure drop through the nozzle that forms jet. As those with extraordinary desires in the art will readily recognize, pressures of up to 80 MPa do not require complex, expensive equipment and that requires attention employed at pressures of 200 MPa and above typically required in the prior art. In this way, the practice of the present invention does not require the use of hydraulic pumps for pressure compensation, high-pressure intensifiers and even accumulators can be avoided or at a minimum greatly simplified. The present invention can be practiced with readily available and economical conventional positive displacement pumps such as piston pumps, which can be hydraulically displaced or similar to the required pressures. At the actual nozzle orifice diameters in the present invention, the nozzle speeds will be in the range of about 75 approximately 610 meters per second (approximately 250 to 2,000 feet per second), preferably approximately 150 to 460 meters per second (approximately 50 to 1,500 feet per second) that have proven to be fully effective in the practice of the present invention. The selection of the abrasive material is not critical in the present invention, and any of the materials commonly employed will be effective. Examples of suitable materials include for illustration alumina, silica, garnet, tungsten carbide, silicon carbide and the like. The reuse of cutting media allows economical use of harder, more expensive abrasives, with resultant improvements in the efficiency of cutting and machining operations. For example, you can substitute silicon carbide in cutting operations when garnet is used for cost containment reasons. In general, the abrasive will conveniently employ concentrations in the formulation at levels from about 5 to 60 by weight, preferably about 25 to 40% by weight We have found that the operation in the preferred range and superior in some cases, is quite effective and in general and substantially higher than the concentrates conventionally used in cutting with abrasive water jet stream. As noted above, abrasive particles may be in the range from 2 to 2,000 microns in their largest dimension (diameter), preferably approximately 20 to 20 microns. For cuts where a fine surface finish is desired, particle sizes of about 20 approximately 100 microns are particularly advantageous. In general it is appropriate to employ the largest particle size consistent with the diameter of the jet-forming orifice to be employed, in which case it is preferred that the larger-sized particle diameter does not exceed about 20% and preferably exceeds about 10% of the diameter of the orifice. If the particle size is larger, there is a risk of "bridging" through the hole, clogging the flow through the nozzle, which is obviously undesirable for currently particles below 20%, rarely occurs bridged, and less of 10% these effects are very rare. Nozzle diameter is usually determined by other parameters. In particular, the diameter of the nozzle orifice is determined by the following parameters: First, the wider the orifice, the wider the jet stream and consequently the cut. Cutting accuracy will generally vary as the inverse diameter of the hole. When cutting thin materials, in general, the smaller the hole, the better the detail precision possible, subject to other parameters. Less cutting med is used per unit section of cutting.

Second, the wider the orifice, the greater the mass flow of the jet stream and consequently the higher the cutting speed. In this way, the wider the hole, the better the cutting speed, subject to other considerations. More cutting medium is used in relation to the cutting length. The balance of two other conflicting considerations will ordinarily overcome other parameters that may influence the diameter of the hole. In the present invention, nozzle diameters of about 0.1 to about 1 millimeter (about 0.004 to about 0.04 inch) can be effectively employed, but in general it is preferred to use diameters of from about 02 to about 0.5 millimeter (about 0.008 to about 0.020 inch) . The orifice can be formed from hard metal alloys, hard shell materials, such as tungsten carbide or silicon, ceramic formulations or crystalline materials such as sapphires or diamond. The selection of suitable materials will ordinarily be determined by the hardness of the selected abrasive and the cost of the nozzle material. Diamond is preferred. The separation distance of assembly, that is to say the distance between the nozzle and the surface of the work piece, has proved to be an important factor in the quality of the cut, but not as important as in the cutting of the jet with abrasive water. Although the cutting quality, particularly the shape and width of the section, is significantly affected by separation of up to about 2.5 c (approximately 1 in), the present invention is capable of cutting at separation distances of up to about 2 about 30 cm (approximately 10 to about 1 inch). Although abrasive blasting can be employed with materials as thick as 3 centimeters (12 inches), these techniques generally require a separation distance of "free air" no greater than about 2.5 cm (about 1 inch). Cutting with jet stream according to the present invention can be used to cut any of the materials for which these techniques have been used to date. Notably, particular materials that are difficult to machine, including many metals and alloys, such as stainless steels , nickel, titanium alloys, glass ceramics, rock materials, such as marble, similar granite and polymer composites and particularly laminated d polymers reinforced with fibers, all are effectively cut with considerable precision by the present techniques. Among the benefits of the present invention, which are achieved by using polymeric media thickened with gel with abrasive slurry, is the ability of the present invention to provide pre-mixed suspensions of fine abrasive particle sizes that have not previously been employed. Sizes of finer abrasive particles at about 200 microns, and particularly less than about 100 microns, for example, were previously not preferred. The use of these fine abrasive particles in conventional abrasive aerodynamic jet stream cutting and cutting tends to result in the abrasive material sealing at angles, loops and bends in abrasive material feed lines, and these fine abrasive materials are also more difficult to introduce into jet streams in a mixed chamber or conventional mixing tube. Due to these difficulties, these small particle sizes have been substantially avoided in the practice of cutting and machining with abrasive jet stream. The use of a suspension of premixed abrasive material in the present invention eliminates the need for additional equipment and supply lines in the nozzle assembly. Fine abrasive particles improve the precision and quality of cutting and machining and reduce damage of abrasive particles to the surfaces of workpieces adjacent to the cuts. Thus, fine abrasive particles can be particularly useful in applications where additional finishing steps can be eliminated. By having an essentially uniform suspension of abrasive materials and with abrasive particles moving at speeds comparable to those of the carrier medium, which is a consequence of using suspensions of premixed abrasive materials, the tendency of the bridging or packing materials to be briskly reduced is significantly reduced. in the mouth of the mouthpiece. Therefore, the diameters of nozzle orifices can be reduced. Depending on the size of abrasive particles, nozzle orifice diameters can be as small as approximately 0.1 mm (approximately 0.004 inch). These smaller orifices provide comparatively smaller diameter jet streams that improve cutting and machining accuracy by producing smaller sections and decreasing media consumption rates. Dispersions of the abrasive in the medium are achieved by simple mixing techniques, and is not narrowly significant for the practice of the present invention. As noted previously, the design and structure of the nozzle elements for use in the system of the present invention is greatly simplified by the removal of the mixing tube, the abrasive feeding mechanism, and the abrasive conveying conduit, typically a hose. The characteristics and their volume, complexity, cost, weight and dependence of judgment and dexterity of the operator, all are eliminated to the considerable benefit of cutting operations and machining with abrasive jet stream.

It is also convenient that the specific design of the nozzle to be used, is configured to minimize the application of shear to the polymer constituent of the flowing medium of stream. Accordingly, it is preferred that the velocity of change d cross-sectional area of the nozzle from the It enters relatively large at the exit of the nozzle orifice, s developed in substantially continuous curves, pairs, avoid as much as possible the presence of edges or other interruptions. Flow acceleration is achieved by reducing the cross-sectional area through which medium is pumped, and high shear stresses are necessarily applied to the polymer. However, it is considered that chain breakdown and polymer degradation are minimized by avoiding edge and similar voltage concentrations, where the rate of change in stress is very high, and proportional to abrupt changes in the velocity of change of the area in the cross section These characteristics in the nozzle also serve to avoid producing turbulent flow in the medium. The jet stream coherence is favored by laminar flow through the nozzle orifice, such that the indicated nozzle configuration serves to minimize current divergence. It is auxiliary to minimize induced shear stresses in the context of all aspects of the present invention. In particular, sufficient shear stress magnitudes must be avoided to generate turbulent flow in the passing medium. Shear stresses of this magnitude for high speed flow are associated with the step over discontinuities and edges. A consequence of this flow is the generation of shear stresses should be in the medium of sufficient magnitude to break polymer bonds. The breakage of covalent polymer bonds with the accompanying irreversible molecular weight reduction are all manifestations of polymer degradation and are best avoided or minimized when possible. As a further aspect of the present invention, there are improvements for media trap designs employed to capture jet streams after passing through or through the work pieces. Even after cutting and machining a work piece, portions of the current, if not all of the current, still travel at high speeds such that specific media trappers are required to minimize backsplash, generation of mist and damage to the workpiece. tool catcher medium. Additionally, it is necessary to design media trap to reduce the noise caused by the rupture of the jet stream and reduce the degradation of the polymer and fracture of the abrasive particles. Previously, elongated tubes were used to trap media. These elongated tubes were shaped and oriented to cause a jet stream to break on the surface walls before the jet streams reached the bottom of the media trap. Alternately, medium-sized traps include replaceable bottom inserts or filled with loose steel balls to effect decomposition of the jet stream. When replaceable funds were used, it was an accepted consequence that jet streams would cut the bottom. To address this disadvantage, medium trap funds were assumed designed for an easy, low cost replacement. Regardless of the type of medium current trap employed, trapped jet streams are subjected to high shear stresses that inevitably promote polymer degradation. The present invention provides a new media trap design as illustrated in cross-sectional view in FIG. 1, with the media trap generally designated by reference numeral 48. A jet stream (50) can be injected into the trap of medium (48) and decelerate slightly. Here, the jet stream (50) does not impact metal surfaces, but is directed to penetrate a contained medium (52). Preferably, this means (52) is the same suspension or solution of polymer thickened with gel as the jet stream (50). Polymer molecules in the jet stream (50) trapped by the media trap (48) decelerate by a substantial distance as opposed to impacting a metal surface and essentially decelerate immediately. This deceleration prolongs avoids generation of magnitudes by shear stress that will be associated with impact on the metal surface. Although many different materials may be employed for the receiving means (52), there are disadvantages in not using the same medium as that of the jet stream (50). These disadvantages include difficulties by dissolution and separation that can even be impossibilities when the medium is to be reused for cutting and machining with jet stream. Depending on the energy of the jet stream (76), and particularly the portion of the current that has passed the cut (52) and the average depth (50), the jet stream (52) can penetrate through the medium ( 52) to the medium trap surface (54). One approach to solving this problem would be to construct a medium trap (48), with sufficient volume to avoid the possibility that the jet stream (50) will penetrate the media trapping surface (50) regardless of the energy of the stream. jet (50). The medium trap (48) of this invention is simple in construction and can be used whether the jet stream (50) is reused or not. Any fluid for the medium (52) including water may be used if the jet stream medium (50) is not to be reused. Since conventional piston displacement pumps can be used to generate effective jet streams (76) with gel-thickened polymers of the present invention, and a displacement pump can also be used to recycle the medium (54), it is possible and indeed It is convenient to assemble the equipment for a cutting and machining system with medium return using this equipment. To use the apparatus, the medium (64) for cutting and machining with jet stream is charged to the cylinder (72) of a positive displacement pump (66). A nozzle (68), preferably having a nozzle structure design substantially as illustrated in Figure 2, is adapted to the outlet of the displacement pump (66), either by a direct connection or by a conduit of high pressure for the medium (75). A hydraulic actuator (70), acting through a piston rod (70), forces the piston head (72) downwards, displacing the means (64) to exit through the hole in the nozzle (68) as a high speed jet stream (76). The jet stream (76) cuts and machines a workpiece (78). After the jet stream cuts and machines the workpiece (78), the now divergent flow of the jet stream (50) passes to the media trap (48). For this particular embodiment, the medium (52) is the same as the medium (64). The moment of the jet stream (50) entering the medium trap (48) is progressively dissipated and the middle of the jet stream (76) is mixed with the medium (52).

When a majority of the medium (64) has passed to the medium trap (48), a portion of the medium (52) can be returned to the filling means (64) in the displacement pump (66) in such a way that the cutting can continue / machining. To return the medium (64) in the displacement pump (66), the pump (80) in the return line (82) is used. The head and piston of the displacement pump (74) is retracted to admit the medium (64) on the compression side of the piston head (74). If necessary, a filter (84) may be provided on the return line (82) to separate waste by filtration, such as those resulting from cutting and machining. This filtering is primarily intended to protect the orifice of the nozzle (68) and to prevent clogging. Magnetic separation of waste can also be used if ferrous or other paramagnetic materials are cut. As previously stated, the force that is provided by the piston head (74) is sufficient to displace medium (64) through the nozzle (68) to produce jet streams (76) that have sufficient energy to effectively machine parts. of work (78). Cost of reduced equipment, increased reliability and improved safety for operating personnel are the benefits that are provided by this embodiment of the present invention. The performance of the present invention for making cuts has been shown to be at least equal and often superior to the performance of prior art techniques. The greatest advantage of the system of the present invention is based on the ability to recycle and reuse the medium, typically 20 to 100 cycles for many of the formulations. Another considerable advantage is the simplification of the equipment required for operations of cutting and machining with abrasive jet stream, operating at lower pressure. These features provide considerable cost savings and reduce dependence on the skills and experience of the equipment operators. The improved coherence of the jet streams in the present invention generally results in narrower width of section compared to those achieved in the prior art in relation to the size of abrasive particles if all other parameters are equal. The narrower section allows greater precision and detail to make cuts and is a significant advantage if considered alone. For a given abrasive particle size, we have also observed that the surface finish of the cutting edges is considerably better than that which can be achieved in the prior art. When coupled with the ability to use smaller particle sizes than those that can be used in the techniques of the previous specialty, it is possible to produce cuts that do not require surface finishing procedures on the cutting edge, reducing the number of operations and the amount of labor and equipment required in production.

While the operating pressures employed in the present invention are materially lower than those employed in the abrasive blasting processes of the prior art, we have found that the cutting speeds do not suffer by comparison and in many cases are higher than those which they can be achieved by the techniques of the previous specialty. EXAMPLES Axes 1 to 3. An aqueous solution of guar gum at 40% by weight is formed by mixing the gum and water at a slightly elevated temperature of approximately 35GC for a period of approximately 30 minutes, until the gum dissolves completely. . To the solution thus formed, 0.60 by weight of a deacetylated polysaccharide in alkali and high molecular weight of mannose, glucose and acetyl ester potassium gluconorate is added and dissolved. To that solution, an equal volume of aqueous solution of 35% by weight of boric acid and 2% by weight of sodium borate is added and mixed until homogeneously formulated, accompanied by the initiation of hydrogel formation. To the forming hydrogel, 50 parts of SiC, having a particle size of 45 microns (325 mesh) is added and the combined materials are thoroughly mixed until a homogeneous dispersion of the abrasive is achieved. The result is a friable powder which is referred to below as a precursor concentrate.

The above precursor composition is generally used in a dry powder form and mixed with various percentages of water, depending on the size of the nozzle orifice through which the medium must pass during cutting and machining with jet stream, together with appropriate percentages of finely divided abrasive for cutting and machining. Preferably, although not necessarily, a minor amount of paraffinic oil or hydrocarbon fat is added to the composition as a humectant to inhibit scale formation on the medium, if not used immediately. The characteristics of the suitable formulations in volume for different sizes of nozzle orifice are listed below in Table 1. TABLE I Example Size% in volume in abrasive volume viscosity orifice volume of static oil (mm) of nozzle water 1 0.129 20-50 1-10 0-20 72,000 2 0.254 10-20 0-5 0-20 368,000 3 0.635 7-12 0-3 0-20 4.520.000 The oil component in the previously defined compositions not only delays or prevents scab formation. It also controls the stickiness. With little or no oil, the medium adheres to the metal as well as to the hands of the operator. A suitable humectant oil is therefore a preferred additive. Occasionally, the storage duration of the previous medium is limited to attack by fungal or bacterial growth. The addition of a very small amount of a biocide, such as methyl for or parahydroxybenzoate, typically in proportions less than about 1% and often less than about 0.5%, is often an aid in controlling that attack. Examples 4 to 26. The following components were combined in a planetary mixer: Component Parts by weight Poliborosiloxane 35.0 Stearic acid 21.5 Light sulfonated castor oil 8.5 Hydrocarbon based fat 35.0 Poliborosiloxane has a molecular weight of 125,000 and a boron to silicon ratio of 1.25. The grease was a lubricating grease for automotive chassis obtained from Exxon. The components were mixed under ambient conditions until a smooth homogenous mixture was achieved and then divided into portions. Each portion was combined and mixed with abrasive particles as indicated in Table II to form a plurality of abrasive jet stream media. Each formulation is adjusted by the addition of stearic acid to produce a resting viscosity of 300,000 cp.

Each of the media formulations was used to cut 1.27 cm (1/4 inch) aluminum plate under the conditions indicated in Table II, and the cuts were evaluated to show the results reported in the table. TABLE V A B C D E F H 4 SiC 40 220 .058 (.02) 4.064 (1.6) 210.9 (3000) 2.54 (1 SiC 25 220 .058 (.02) .0635 .25) 281.2 (4000) 5.08 (2 6 Garnet 50 220 .058 (.02) .0635 .25) 281.2 (4000) 2.54 (1 7 BC 58 320 .038Í.015) .1905 .075) 506.16 (7200) 5.08 (2 8 SiC 58 320 .038Í.015) .1905 .075) 520.22 (7400) 5.08 (2 9 SiC 58 320 .038 (.015) .1905 .075) 506.16 (7200) 5.08 (2 SiC 58 320 .058 (.02) 1,905 .75) 520.22 (7400) 5.08 (2 11 SiC 58 320 .058Í.02) 1,905 .75) 520.22 (7400) 5.08 (2 12 SiC 58 320 .058 (.02) 1,905 .75) 520.22 (7400) 5.08 (2 13 SiC 58 500 .038 (.015) .1905 .075) 499.13 (7100) 2.54 (1 14 SiC 58 500 .058 (.02) .1905 .075) 499.13 (7100) 2.54 (1 SiC 58 320 .058 (.02) .1905 .075) 499.13 (7100) 5.08 (2 16 SiC 58 320 .058 (.02) .1905 .075) 492.1 (7000) 2.54 (1 17 SiC 58 320 .058 (.02) 1.27 (.5) 506.16 (7200) 5.08 (2 18 SiC 58 320 .058 (.02) 2.54 (1) 506.16 (7200) 5.08 (2 19 SiC 58 320 .058 (.02) 3.81 (1.5) 506.16 (7200) 5.08 (2 SiC 58 320 .058 (.02) .1905 (.075) 492.1 (7000) 2.54 (1 21 SiC 58 320 .058 (.02) .1905 (.075) 492.1 (7000) 2.54 (1 22 SiC 25 320 .0305Í.012) 1.27 (.5) 681.91 (9700) 2.54 (1 TABLE V (Cont.) ABQDEFSB 23 SiC 25 320 .0305 (.012) 1.27 (.5) 681.91 (9700) 2.54 (1 ) 24 SiC 25 320 .0305 (.012) 1.27 (.5) 681.91 (9700) 2.54 (1) SiC 25 320 .0254 (.01) 1.27 (.5) 681.91 (9700) 2.54 (1) 26 SiC 25 320 .0232 (.008) 1.27 (.5) 681.91 (9700) 2.54 (1) TABLE V (Continued) 4 .0762 (.058) .094 (.037) 1,550 1,855 80.00 .0762 (.03) .0508 (.02) 1,500 1,000 12.50 6 .0228 (.09) .01397 (.055) 1,636 2,750 12.50 7 .0762 (.03) .0762 (.03) 1,000 2,000 5.00 8 .071K.028) .0939 (.037) .757 2.467 5.00 9 .0914 (.036) .0787 (.031) 1,161 2,067 5.00 .165K.065) .0838 (.033) 1.970 1.650 37.50 11 .1829 (.072) .0813 (.032) 2,250 1,600 37.50 12 .165K.065) .0838 (.033) 1.970 1.650 37.50 13 .0939 (.037) .0889 (.035) 1.057 2.333 5.00 14 .0889 (.035) .0762 (.03) 1,167 1,500 3.75 .0965 (.038) .0838 (.033) 1,152 1,650 3.75 16 .1016 (.04) .0889 (.035) 1.143 1.750 3.75 17 .1727 (.068) .0889 (.035) 1.943 1.750 25.00 18 .2032 (.08) .1143 (.045) 1,778 2,250 50.00 19 .2489 (.098), 1092 (.043) 2,279 2,150 75.00 .1143 (.045) .0813 (.032) 1,406 1,600 3.75 TABLE V (Continued) A I K L M 21 .0939 (.037) .0836 (.034) 1,088 1,700 3 .75 22 .1448 (, .057) .088 (.035) 1,629 2,917 41 .67 23 .1625 (, .064) .01117 (.044) 1.455 3.667 41. .67 24 .2032 (.08) .0127 (.05) 1,600 4,167 41 .67 .1016 (, .04) .0508 (.02) 2,000 2,000 50, .00 26 .0889 (, .035) .0457 (.018) 1.944 2.250 62 .50 Legend A = Example No. B = Abrasive C = Conc. (% By weight) D = Mesh E = Nozzle diameter, cm (in) [dn] F = separation, cm (in) [SOD] G = Pressure kg / cm2 (psi) H = Feed rate cm (in) / min I = Section top cm (in) [kt] J = bottom of cut cm (in) [kb] K = Portion proportion Kt / Kb L = Portion size Kb / Km] M = SOD / dn As illustrated by table II, fast, efficient and high quality cuts are obtained. Examples 27 to 62 The base formulation employed in Examples 4 to 26 was again used, and mixed with abrasives as set forth in Table III, the viscosity was again adjusted with stearic acid to a resting viscosity of 300,000 cp, and The formulation was used to cut aluminum plate of 1.27 cm (0.25 inch). The cutting conditions are set forth in Table III. The characteristics of the cutting edges of the plate were measured for surface roughness. The measured values are established in columns G and H of Table III. TABLE VI A B £ D I F S H 27 SiC 220 1.27 (0.5) 513.19 (7300) 12.7 (5) 53.15 1.35 28 SiC 220 1.27 (0.5) 513.19 (7300) 15.24 (6) 60.241.53 29 SiC 220 1.27 (0.5) 513.19 (7300) 17.78 (7) 53.941.37 SiC 220 1.27 (0.5) 513.19 (7300) 20.32 (8) 74.411.89 31 SiC 220 1.27 (0.5) 513.19 (7300) 22.86 (9) 72.051.83 32 SiC 220 1.27 (0.5) 513.19 (7300) 2.54 (1) 40.551.03 33 SiC 220 1.27 (0.5) 513.19 (7300) 2.54 (1) 50.001.27 34 BC 320 0.19 (.075) 506.16 (7200) 5.08 (2) 33.460.85 BC 320 0.19 (.075) 506.16 (7200) 5.08 (2) 46.461.18 36 BC 320 0.19Í.075) 506.16 (7200) 5.08 (2) 92.132.34 37 BC 320 0.19 (.075) 506.16 (7200) 5.08 (2) 62.99 1.6 38 BC 320 0.19 (.075) 506.16 (7200) 5.08 (2) 43.701.11 39 SiC 320 0.19Í.075) 492.1 (7000) 5.08 (2) 32.280.82 40 SiC 320 0.19 (.075) 492.1 (7000) 5.08 (2) 26,770.68 TABLE VI (Cont.) A B C. D E F £ H 41 SiC 320 0.19 (.075) 492.1 (7000) 5.08 (2) 27.56 0.7 42 SiC 320 1.27 (0.5) 492.1 (7000) 5.08 (2) 35.830.91 43 SiC 320 1.27 (0.5) 421.8 (6000) 5.08 (2) 53,541.36 44 SiC 320 1.27 (0.5) 351.5 (5000) 5.08 (2) 51.18 1.3 45 SiC 500 1.59i.625) 537.8 (7650) 5.08 (2) 49.611.26 46 SiC 500 1.59 (.625) 537.8 (7650) 2.54 (1) 26.380.67 47 SiC 500 1.59 (.625) 537.8 (7650) 2.54 (1) 52.361.33 48 SiC 500 1.59Í.625) 537.8 (7650) 5.08 (2) 52.761.34 49 SiC 500 1.59 (.625) 537.8 (7650) 7.62 (3) 113.782.89 50 SiC 500 0.19 (.075) 492.1 (7000) 2.54 (1) 28.74 0.73 51 SiC 500 0.19Í.075) 492.1 (7000) 2.54 (1) 22.83 0.58 52 SiC 500 0.19Í.075) 492.1 (7000) 2.54 (1) 56.69 1.44 53 SiC 500 0.19 (.075) 492.1 (7000) 2.54 (1) 62.60 1.59 54 SiC 500 0.19 (.075) 492.1 (7000) 2.54 (1) 15.35 0.39 55 SiC 500 0.19 (.075) 492.1 (7000) 2.54 (1) 28.35 0.72 56 SiC 500 0.19 (.075) 492.1 (7000) 2.54 (1) 14.96 0.38 57 SiC 320 0.19 (.075) 513.19 (7300) 5.08 (2) 82.68 2.1 58 SiC 320 0.19 (.075) 513.19 (7300) 5.08 (2) 106.30 2.7 59 SiC 320 0.19Í.075) 513.19 (7300) 5.08 (2) 145.67 3.7 60 SiC 320 0.19Í.075) 504.05 (7170) 2.54 (1) 62.99 1.6 61 SiC 320 0.19 (.075) 504.05 (7170) 2.54 (1) 68.50 1.74 62 SiC 320 0.19 (.075) 504.05 (7170) 2.54 (1) 76.38 1.94 A = Example

Claims (46)

1. D = distance of separation cm (in) G = Ra 77cm (? Inch) B = Abrasive E = Pressure Kg / cm2 (psi) H = Ra (μm) C = Mesh F = Feed rate cm / min (inch / minute ) As those of ordinary skill in the art will readily recognize, the surface finishes measured and reported in Table III are of exceptional quality in the context of cutting with abrasive jet stream. The above examples are intended as illustrative of the present invention and do not limit its scope. The invention is defined and limited by the following claims, which establish in a particular way the scope of the invention. NOVELTY OF THE INVENTION Having described the invention as above, the content of the following is claimed as property: CLAIMS 1.- In the method of machining and cutting with abrasive jet stream, where a plurality of abrasive particles are suspended in a medium of continuous flow jet and projecting high pressure velocity in a work piece, with the improvement comprising: A. forming the medium of a polymer having sacrificial sacrificial chemical bonds that preferably break under high shear conditions; B. projecting the medium and abrasive suspended in the workpiece to perform the machining and cutting under shear conditions that break the sacrificial chemical bonds reformable; C. reform chemical bonds; and D. recycle the medium and abrasive to reuse in the method.
2. 2. Method as described in claim 1, wherein the medium projects through an orifice to form a jet stream at a pressure of about 14 to 80 MPa.
3. 3. - Method as described in claim 2, wherein the jet stream is projected at a speed of about 61 to 1305 meters per second (200 to 1000 feet per second).
4. 4. Method as described in claim 1, wherein the abrasive particles have a particle size from about 2 about 1,600 microns in its largest dimension.
5. 5. Method as described in claim 1, wherein the medium is an aqueous gel of a water-soluble polymer ionically crosslinked with a metal compound of group II to group VIIII.
6. 6. - Method as described in claim 1, wherein the medium is a non-aqueous plasticized polymer that forms intermolecular bonds to form a gel.
7. 7. Method as described in claim 1, wherein the gel has a static viscosity of about 200,000 to 600,000 centipoise.
8. 8. Method as described in claim 1, wherein the medium is an aqueous hydrogel of about 1 about 20% by volume of a water soluble polymer containing gelled hydroxyl group by formation of intermolecular hydrogen bonds promoted by the action of a gelation promoter containing a metal from group II to group VIII.
9. 9. Method as described in claim 1, wherein the jet stream is formed by forcing the thickened aqueous medium through a nozzle means having an inner inlet port surface of an inner exit orifice surface. with an interconnected transition zone surface; the entire entrance door surface, the transition surface and zone and the exit orifice surface are in contact with the thickened aqueous medium passing through the nozzle means and the transition zone surface and the orifice surface output that defines a continuous function without interruptions.
10. 10. - Method as described in claim 4, wherein up to 50% by weight of the abrasive particles are added to the medium.
11. 11. Method as described in claim 5, wherein the water soluble polymer is a member selected from the group consisting of guar gum and its hydroxypropyl derivatives, cellulose derivatives including carboxymethyl ethyl cellulose or synthetic hydroxyl functional polymers including polyacryl amide and polymethyl ethylene.
12. 12. Method as described in claim 8, wherein the medium comprises about 1 about 20% by volume of the water soluble polymer.
13. 13. Method as described in claim 5, wherein the aqueous medium comprises about 50 about 75 weight percent guar gum, about 30 about 40 weight boric acid and about 1.0 about 2.5 weight percent borate. of sodium.
14. 14. - Method for cutting and machining with jet stream, wherein the collection of the jet stream in a trap means after the jet stream has worked on a workpiece, wherein the entrapment means comprise a container of containment and a deceleration means to decelerate the jet stream.
15. 15. - Method as described in claim 14, wherein the deceleration means comprises the same medium that is used to form the jet stream.
16. 16. Method as described in claim 15, wherein the deceleration means and the decelerated medium are recycled for reuse as a jet stream medium.
17. 17. Method as described in claim 1, wherein up to 10% by weight of a wetting oil is added to the thickened aqueous medium.
18. 18. Method as described in claim 1, wherein a biocide is added to the thickened aqueous medium.
19. 19. Method as described in claim 8, wherein a soluble thixotropic is provided for improved rheological behavior.
20. 20. Method as described in claim 11, wherein about 0.25 to about 0.60 by weight of a high molecular weight polysaccharide is added to the gelation agent.
21. 21. Method as described in claim 12, wherein the polysaccharide comprises the acetyl ester derivatized alkali deacetylated polymer selected from the group consisting of mannose, glucose, potassium glucuronate and mixtures thereof.
22. 22. A polymer containing an abrasive jet stream cutting means comprising a particulate abrasive dispersed in a polymer composition, the polymer having reformable sacrificial chemical bonds, which preferably break under high shear conditions and which are reformed under low stress conditions, the composition of the polymer has a viscosity at rest of about 100,000 about 500,000 centipoise, and a dynamic viscosity of about 3,000 to about 30,000 poises under shear conditions represented by the circulation of the medium through an orifice having a diameter from about 0.1 to about 1 mm at a pressure of about 14 about 80 MPa.
23. 23. Abrasive jet stream cutting media according to claim 22, wherein the sacrificial sacrificial chemical bonds are gel forming interlacing bonds, selected from the group consisting of ionic bonds and intermolecular bonds.
24. 24. Abrasive jet stream cutting medium according to claim 23, wherein the medium comprises an aqueous hydrogel of a water soluble polymer and a gel promoter.
25. 25. Abrasive jet stream cutting medium according to claim 23, wherein the water-soluble polymer comprises water and its hydroxypropyl derivatives, cellulose derivatives including carboxymethyl ethyl cellulose, or synthetic hydroxyl-terminated polymers including polyacrylamide and polyoxymethylene and the The gel promoter comprises a metal oxide or organic metal compound for promoting hydrogel formation comprising a member selected from the group consisting of boric acid, sodium borate, organometallic compounds of at least one metal from group II to group VIII and their mixtures
26. 26. Abrasive jet stream cutting medium according to claim 17, wherein the gel promoter is a metal organ compound of a selected metal consisting of titanium, aluminum, chromium, zinc, zirconium and mixtures thereof.
27. 27. Abrasive jet stream cutting medium according to claim 26, wherein the hydrogel comprises from about 1 to about 20 volume percent of the water soluble polymer and about 99 about 80 weight percent of water.
28. 28. Abrasive jet stream cutting medium according to claim 24, wherein the medium further comprises a water soluble isotropic.
29. 29. Abrasive jet stream cutting medium according to claim 24, wherein the hydrogel polymer comprises about 50 to about 75 weight percent guar gum reacted with about 40 weight percent boric acid and about 1.0 g. approximately 2.5 percent by weight of borax.
30. 30. Cutting medium with abrasive jet stream according to claim 24, wherein the medium further comprises about 0.25 to 0.60 percent by weight of high molecular weight, water soluble polysugar.
31. 31. Cutting medium with abrasive jet stream according to claim 30, wherein the polysaccharide comprises acetyl ether deacetylated in alkali of potassium gluconorate.
32. 32. - Cutting medium with abrasive jet stream according to claim 24, wherein the medium further comprises about 0.5 to about 10.0 by weight of a wetting oil.
33. 33. Abrasive jet stream cutting medium according to claim 23, wherein the abrasive particles comprise alumina, silica, garnet, tungsten carbide, silicon carbide and mixtures thereof.
34. 34. Abrasive jet stream cutting media according to claim 22, wherein a non-aqueous plasticized interlaced polymer gel, interlaced by intermolecular bonds, the medium has a static viscosity of about 200,000 to about 600,000.
35. 35.- Cutting medium with abrasive jet stream according to claim 34, wherein the polymer is a polysiloxane having boron-oxygen intermolecular interlacing bonds.
36. 36. Abrasive jet stream cutting medium according to claim 34, wherein the polybrosiloxane has a molecular weight from about 200,000 to about 750,000 and an atomic ratio of boron-silicon from about 10 to about 100.
37. 37.- Medium of cutting with abrasive jet stream according to claim 22, wherein the abrasive particles have a maximum dimension from about 2 about 1400 micrometers.
38. 38.- Cutting medium with abrasive jet stream according to claim 22, wherein the abrasive particles have a maximum dimension from about 10 about 200 microns.
39. 39. Abrasive jet stream cutting medium according to claim 22, wherein the abrasive particles have a maximum dimension from about 20 about 200 microns.
40. 40. Abrasive jet stream cutting medium according to claim 22, wherein the medium has a viscosity at rest of about 300,000 cp.
41. 41.- A cutting and machining apparatus with jet stream capable of forming a jet stream using an interlaced polymer gel medium, comprising a nozzle means to form the jet stream, with the nozzle means having a jet entrance door and an exit orifice, with a transition zone interconnecting the entrance door with the exit orifice, the transition zone has a surface in contact with the interlaced polymer gel medium that passes through the nozzle means , the surface of the transition zone is formed into substantially continuous, homogeneous curves, and the outlet orifice has a constant cross-sectional area and a length-to-diameter ratio of at least about 3.
42. 42. The cutting apparatus and jet-jet machining having a jet stream formed from an interlaced polymer gel medium, comprising medium trap mounts, wherein the Jet stream is directed after cutting and machining a work piece, the middle trap assemblies contain a decelerating medium, to decelerate the jet stream.
43. 43. The jet stream cutting and machining apparatus as described in claim 41, further comprising the interlaced polymer gel medium containing abrasive particles.
44. 44. The jet stream cutting and machining apparatus as described in claim 43, further comprises an interlaced polymer gel medium containing a polymer gel thickener.
45. 45. - The jet stream cutting and machining apparatus as described in claim 42, the decelerating medium is the interlaced polymer gel medium thickened with polymer gel.
46. 46. The jet cutting and machining apparatus as described in claim 42, the decelerating medium, after decelerating the jet stream is used to form a jet stream. IN WITNESS WHEREOVER, I have signed the above description and Novelty of the Invention as proxy of EXTRUDE HONE CORPORATION, in Mexico City, D. F., today, August 26, 1994. p.p. EXTRUDE HONE CORPORATION SAMUEL DORANTES F. RS / sms + / [51] / Rhoades