Abstract:
The invention relates to a method for producing sheets of polymeric surfacing, the sheets produced thereby, and the apparatus used to produce the sheets. The method includes providing a solid polymeric slab, and slicing the slab into sheets of surfacing. The sheets may include polymeric particles contained in a polymeric matrix. The particles may have a maximum linear dimension that is greater than the final thickness of the sheets, thereby resulting in an aesthetically pleasing “chunky” appearance. The apparatus used to slice the sheets produces a relatively smooth, uniform surface, and is capable of dramatically limiting the amount of variation in thickness within a finished sheet.

Description:
TECHNICAL FIELD 
     The present invention relates to apparatus used to cut polymer compositions produced in slabs or sheets and meant to simulate, for example, stone such as marble or granite. The present invention further relates to apparatus for slicing such slabs into sheets. 
     BACKGROUND OF THE INVENTION 
     Solid polymeric surfacing has a variety of uses, including household, commercial, and industrial uses in which durable, sometimes renewable, decorative surfaces are desired. Such surfaces include, but are not limited to, kitchen and other countertops, table tops, bathroom vanities, divider panels, and wall surfacing. These surfacing products may be produced so as to simulate stone such as marble or granite. 
     For example, U.S. Pat. Nos. 4,433,070, and 4,446,177 disclose compositions for such products. Additionally, U.S. Pat. Nos. 4,085,246 by Buser et al, 5,244,941 by Bruckbauer et al, and 5,242,968 by Minghetti et al, all of which are hereby incorporated by reference herein, disclose such compositions. U.S. Pat. No. 5,244,941 discloses a composition that is particularly useful as artificial stone surfacing, due to the inclusion of chips of a previously cured thermosetting resinous compound in the composition; also disclosed therein is the process for producing the surfacing. These products are typically produced in solid slabs about ½ inch in thickness. The result is surfacing of high quality, but relatively high cost. 
     It has been found previously that production and provision of these products in sheets about ⅛ inch in thickness results in a type of solid surfacing “veneer” having benefits similar to those of the ½ inch product, but at a significant reduction in cost. The ⅛ sheets are typically bonded to inexpensive particle board, or the like, resulting in a relatively strong but less expensive surfacing product. 
     The only method of producing ⅛ surfacing known to the prior art is with equipment that is prohibitively large and prohibitively expensive. Examples of such equipment are disclosed in U.S. Pat. Nos. 3,371,383 and 3,376,371. These references disclose a dual belt continuous casting system. This very expensive, very large, dual belt system is the only system that provides the degree of dimensional control necessary to produce a ⅛ thick sheet within required specifications and tolerances. The ½ inch product is produced on a similar single or dual belt system. 
     Problems with this prior art method of producing ⅛ sheets of surfacing also include the fact that the aesthetic results of the surfacing are limited when an artificial stone appearance is desired. As disclosed in U.S. Pat. No. 5,244,941, solid particulate is added to a resin matrix to give the surfacing a simulated stone appearance. Particulate is typically irregular in shape, but most approaches a quasi-spheroidal shape, and may be discussed as such for purposes herein. Naturally, the size of the particulate added to the resin matrix during the casting process is limited to the final thickness of the slabs; i.e, cast ⅛ inch thick surfacing cannot contain particulate that does not fit within the thickness of the sheet. This prohibits production of ⅛ inch thick product containing large sized particles that would result in a “chunky” look that occurs in some natural stone. This “chunky” look has been determined to be very aesthetically pleasing to consumers. 
     Lamellar, or disk-shaped, particles may be used, but with unacceptable results. Such particle shapes could have a maximum dimension that is greater than the sheet thickness and still fit within the sheet. However, the resin matrix typically is somewhat transparent, and the resultant effect from using lamellar shaped particles would not resemble the desirable “chunky” stone appearance. Instead the result would be oval and oblong particles that may partially disappear into the thickness of the sheet. Also, they may have a tendency to align during the sheet casting process, resulting in a less than random distribution of particles in the sheet. 
     Indeed, the only method of producing surfacing with a “chunky” look to date is by sanding or grinding relatively thick surfacing down in thickness to expose the interior (and thereby, a larger degree of flattened exposed surface area) of the particulate. This is necessary to produce a sheet with a surface look that is truly representative of the random nature of the particulate as dispersed in the resin matrix. As cast, the surface look of the slabs is not representative. Only the outer edges of the particulate approach the surface of the slab, and even then in only a tangential fashion. The random particulate pattern is not exposed until the sheet surface is sanded down. Indeed, some in the art feel that the sheet surfaces must be sanded down by ¼ to ½ the diameter of the largest particulate size in the sheet to get the best aesthetic results. As one can plainly see, sheets are produced by this method at the expense of grinding off a huge amount of the material. Obviously, this method is very costly, in terms of the necessary manufacturing equipment, increased manufacturing time, and wasted surfacing material. 
     To produce relatively thin sheets of veneer, Applicants have attempted to slice ½ inch slabs of solid polymeric surfacing through their thickness using the type of saw that is typically used for cutting marble and granite. These attempts have been unsuccessful, in that the stone saws remove too much material during cutting and also produce a very rough, irregular surface that is unacceptable in solid surfacing veneer. These and other available saws that have been tried result in unacceptable levels of thickness variation within a sheet, unacceptable sheet curvature, unacceptable surface roughness and irregularity, an unacceptable decrease in sheet durability, and a high frequency of saw blade breakage. In fact, every industrial quality saw expert approached about developing a saw for such an application stated that it would be “impossible”. 
     As a result, there exists a need to produce solid surfacing veneer, and in fact various thicknesses of solid surfacing, in a way that does not require the very large and expensive prior art equipment. There also exists a need for a method to produce simulated stone solid surfacing with an aesthetically pleasing “chunky” look, which cannot be accomplished by the prior art method. There also exists a need for apparatus that may be used to slice through the thickness of slabs of solid polymeric surfacing that overcomes the problems with prior art equipment. 
     SUMMARY OF THE INVENTION 
     Disclosed is a method for producing sheets of polymeric surfacing and the sheets therefrom. The method includes providing a solid polymeric slab, and cutting the slab into sheets of surfacing. The final thickness of the sheets may vary to a minimum of about ⅛ inch. 
     The disclosed method may include the steps of providing a resin matrix syrup, providing relatively solid polymeric particles, coating the particles with an adhesion promoter, combining the particles and the syrup into a mixture, forming the mixture into a solidified slab, and cutting the slab into sheets of surfacing. The particles may have a maximum linear dimension that is greater than the final thickness of the sheets. 
     Also disclosed is apparatus for slicing a workpiece, most preferably a slab of polymeric material, into sheets. The apparatus includes a continuous blade band saw having a slicing blade with a cutting edge, and at least two blade guides to stabilize the position of the blade relative to the workpiece. The blade is under a tension of from about 7500 pounds per square inch (psi) to about 35000 psi. The blade has a width of from about 2 inches to about 4 inches, the cutting edge has from about 2 to about 4 teeth per inch, and the blade has a kerf of from about 0.050 inches to about 0.075 inches. During the slicing operation, the blade preferably travels at a linear speed of from about 5000 feet per minute to about 10000 feet per minute. 
     Also included are a workpiece support member for supporting the workpiece during slicing, a fluid supply for cooling the blade and workpiece during slicing, and a workpiece stabilizing member located between the support member and the blade. The workpiece-stabilizing member may be at least one set of pinch rollers, which preferably apply a pressure on the workpiece of from about 50 psi to about 100 psi, and more preferably from about 70 psi to about 90 psi. When the workpiece and blade cutting edge are moved toward each other, the stabilizing member holds the workpiece firmly in place with respect to the blade at a location just prior to the workpiece entering the blade. 
     The workpiece has a longitudinal axis oriented perpendicular to a direction of blade travel during slicing. Workpiece guides maintain the longitudinal axis of the workpiece in a substantially perpendicular orientation to the direction of blade travel during slicing. The blade rides on a drive wheel and at least one idler wheel, which support and drive the blade. Each of these wheels preferably has a diameter of from about 24 inches to about 48 inches. Most preferably, a finished sheet after slicing has a maximum standard deviation in thickness of about 0.002 inches. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a portion of a sheet of solid surface veneer having particles with maximum linear dimensions greater than the sheet thickness. 
     FIG. 2A shows solid surface veneer of the prior art; line F—F shows the depth to which the surface must be sanded down to expose the particulate for an artificial stone appearance. 
     FIG. 2B shows the veneer of FIG. 2A after the surface is sanded down. 
     FIG. 3A shows a relatively thick piece of prior art solid surfacing; line F—F shows the depth to which the surface must be sanded down to expose a substantial amount of the interior of the particulate, thereby producing a “chunky” artificial stone appearance. 
     FIG. 3B shows the surfacing of FIG. 3A after the surface is sanded down. 
     FIG. 4A shows a slab of solid surfacing of the present invention, containing large sized particulate. 
     FIG. 4B shows the slab of FIG. 4A after slicing the slab into three relatively thin pieces of solid surface veneer, thereby exposing a substantial amount of the interior of the particulate, and resulting in a “chunky” artificial stone appearance, without the need for grinding excessive amounts of material from the slab. 
     FIGS. 5A and 5B show an alternative to FIGS. 4A and 4B, wherein a majority of the particulate is very large in size, thereby resulting in a “super-chunky” appearance. 
     FIG. 6 shows an elevational view of an embodiment of a saw of the present invention, used to slice slabs of solid surfacing into relatively thin sheets. 
     FIG. 7 shows an exploded view of the pinch roller and blade area of FIG.  6 . 
     FIG. 8 is a top view of the pinch roller and blade area of FIG.  7 . 
     FIG. 9 shows a side elevational view of the saw of FIG. 6, with certain structural elements removed for clarity. 
     FIG. 10 shows an exploded view of the pinch roller and blade area of FIG. 9, as it appears while slicing through a slab of polymeric material during the slicing operation. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A. Method of Production and Article 
     Disclosed is a method for producing sheets of polymeric surfacing, otherwise referred to as artificial stone surfacing, solid surfacing, or solid surfacing veneer, and the sheets resulting from this method. The present method particularly allows the manufacture of solid surfacing veneer with a “chunky” appearance provided by the particulate in the surfacing. In other words, the “chunks” of particulate in the surface of the sheets have a maximum size or linear dimension that is greater than the thickness of the sheet. Referring to FIG. 1, a portion of a sheet of veneer “V” is shown having particles A and B encased in resin matrix C. Maximum linear dimensions of particles A and B are A 1  and B 1  respectively, both dimensions being greater than sheet thickness “T”. Thickness “T” is typically on the order of about ⅛ inches. In the prior art, this “chunky” look has only been achieved in sheets greater than ¼ inch in thickness, and only through sanding or grinding a relatively substantial amount of material from the sheet surface, resulting in increased production time and cost, and increased wasted material. 
     FIG. 2A shows a slab of solid surfacing veneer  10  in the “as cast” form. Prior art slabs of this type are usually made using a two-belt casting system as described, for example, in U.S. Pat. Nos. 3,371,383 and 3,376,371. Shown are resin matrix  12  and particulate  14 . Note that the maximum diameter of each piece of particulate  14  may not be greater than sheet thickness “T”, or bulges would result in sheet  10  where particulate  14  extended out past surface “S” of slab  10 ; such bulges would interfere with the casting process and result in unacceptable product. Line F—F denotes the depth to which surface “S” is sanded to help expose a portion of the particulate thereby bringing out the artificial stone appearance. Note in FIG. 2B that only a small amount of the particulate  14  interior may be exposed by this prior art method. The result is an artificial stone appearance, but with a relatively small granular pattern. 
     FIG. 3A shows a piece of the relatively thick prior art solid surfacing  110  which may contain larger sized particles  114  because of the greater sheet thickness. To expose a large amount of particle  114  interior, the surface S of the slab must be ground down to the level at line F—F. The result is still a relatively thick and expensive product. The result is also a chunky appearance, as demonstrated by FIG. 3B, but at the expense of increased manufacturing time and cost, and substantial wasted material. 
     FIG. 4A shows a slab of artificial stone  210  of the present invention. Particulate  214  may be of a diameter as great as the slab thickness. By slicing the slab through its thickness, multiple sheets of solid surface veneer  216  are produced, as shown in FIG.  4 B. Note that because the particulate  214  is sliced through its interior, the result is a “chunky” appearance without the need for the excessive surface grinding necessary in the prior art method to produce a similar appearance. A slab of about ½ inch in thickness may be sliced into 3 sheets of veneer each about ⅛ inch in thickness, accounting for material lost in the slicing operation. The material lost in the slicing operation is still a great reduction in waste over the prior art method of producing the “chunky” appearance. The present veneer is produced without the need for the excessively large and expensive dual-belt casting equipment, without significant material waste, and without excessive surfacing grinding time, equipment and cost. FIGS. 5A and 5B show an alternative of the present invention in which the size of a majority of the particulate  314  used in the slab  310  approaches the thickness of the slab. The result is a sheet of veneer  316  with a “super-chunky” appearance. 
     In fact, it is anticipated that the present method may be used to overcome the problems described above in cutting sheets of various thicknesses from about ⅛ inches up to about ½ inches, or more if the specific application for thicker sheets warrants such. For example, a 2 inch thick slab of solid polymeric surfacing may be sliced into three sheets of about, or a little less than, ½ inches in thickness, and three sheets of about, or a little less than, ⅛ inches in thickness, accounting for material lost during slicing. In any event and for any final sheet thickness, the present method achieves a chunky surface appearance without excessive surface grinding and wasted material. 
     The particles that are added to the resin matrix to achieve the “chunky” artificial stone appearance may be composed of many different material types. For example, particles may be made of thermoplastic resins such as acrylic resins, acrylic blends with polycarbonate or polystyrene, polyesters, polyamides, and polyolefins. Particles may also be made of thermoset resins such as unsaturated polyesters and blends with acrylics or polyvinylacetates or polystyrenes, melamine formaldehyde, phenol formaldehyde, epoxies, and vinyl esters. Particles may additionally be of organometallic resins such as the thermoplastics and thermosets listed above along with sol gel resins based on tetraethoxyortho silicate or triethoxy aluminate or tetralkoxy titanates. Finally, particles may be composed of minerals like granite, marble, or quartz, or may be man made glass, ceramics, sol gels, or cement. 
     The resin matrix may also be composed of many different material types. For example, the resin matrix may be made of thermoplastic resins such as acrylic resins, acrylic blends with polycarbonate or polystyrene, polyesters, polyamides, and polyolefins. The matrix may also be made of thermoset resins such as unsaturated polyesters and blends with acrylics or polyvinylacetates or polystyrenes, melamine formaldehyde, phenol formaldehyde, epoxies, and vinyl esters. The matrix may additionally be of organometallic resins such as the thermoplastics and thermosets listed above along with sol gel resins based on tetraethoxyortho silicate or triethoxy aluminate or tetralkoxy titanates. Finally, the matrix may be composed of inorganics (e.g, cements). 
     One specific example of a particle material is a particulate manufactured and sold by Amoco Corp. under the trade name “AMODEL 1460”. AMODEL 1460 is an engineering thermoplastic and is supplied in pellet form. The composition of the pellet is about 40% polyphthalamide resin and 60% wollastonite, a mineral filler known in the art. Pigments may be added to vary the color of the pellets. The weight percentage of wollastonite may be reduced to compensate for the addition of pigments. The pellets may be pulverized and sized according to the desired aesthetic effect in the final sheets of surfacing. 
     The particles may be treated or coated with an adhesion promoter or coupling agent prior to being mixed with the resin matrix. The purpose of such coating is to promote adhesion between the surface of the particles and the resin matrix; in other words, the purpose is to form a bond between the particles and the matrix. This bond prevents gaps, inclusions, and the like from occurring between the particles and the resin matrix, which could initiate cracks, etc. Such treating is particularly important in the case of the present invention because inclusions in a slab of solid surfacing may result in stress cracking, crazing, and like defects after cutting through the slab, which will be disclosed in more detail below. 
     Examples of adhesion promoters are the organofunctional silane products manufactured and sold by OSI of Tarrytown, N.Y. (e.g, AMINO A1100, METHACRYL A-172, and EPOXY A-187). These are dual-function molecules that contain an organofunctional group and a hydrolyzable group; they can react with a wide variety of organic and inorganic materials. They may be used as a filler treatment for improved filler-to-resin coupling and filler dispersion in thermoset and thermoplastic resins. For example, the organofunctional silane sold by OSI under the trade name “AMINO A-1100”, whose chemical name is gamma-aminopropyltriethoxysilane, is one adhesion promoter that is generally effective when coupling particles into an acrylic resin matrix. Additionally, Dow Corning produces silanes, e.g, Z-6020 diamino and Z-6040 epoxy. Typically, the particles are coated with the adhesion promoter in a twin-shell blender of the type sold by Patterson-Kelly Co. of East Stroudsburg, Pa. 
     B. Apparatus for Production 
     An embodiment of the solid surfacing slicing saw of the present invention is shown in FIGS. 6-10. FIG. 6 shows an elevational view of the front of saw  20 , or the area of saw  20  that the polymeric slabs or workpieces would be fed into. The slabs would be fed into saw  20  lying flat, or horizontally, on a conveyor belt, but it is also-anticipated that slabs could be fed into saw  20  in a vertical orientation if saw  20  were configured to accommodate such vertical orientation. 
     Blade  22  rides on and is driven by drive wheel  24  and idler wheel  25 . Blade  22  is preferably from about 2 inches to about 4 inches in width, and has a cutting edge with preferably from about 2 to about 4 teeth per inch. The blade is typically made of steel and the teeth are preferably carbide tipped. The preferred range of blade kerf (i.e., the thickness of the cut made by blade  22 ) is from about 0.050 inches to about 0.075 inches, with the most preferred kerf being about 0.052 inches. During slicing, blade  22  travels at a preferred linear speed of from about 5000 feet per minute to about 10000 feet per minute, while under a tension of from about 7500 pounds per square inch (psi) to about 35000 psi. More preferred ranges of speed and tension are from about 8000 feet per minute to about 9000 feet per minute, and from about 10000 psi to about 25000 psi respectively. 
     Drive wheel  24  and idler wheel  25  carry blade  22 . Drive wheel  24  is driven by drive motor  26 , typically through a drive belt (see drive belt enclosure  27  in FIG.  9 ). Drive motor  26  is typically a 25 horsepower, 240/480 volt, 3 phase, AC/DC variable drive motor, to accommodate the pressure exerted on blade  22  during slicing. Wheels  24  and  25  are preferably from about 24 inches to about 48 inches in diameter, with the most preferred diameter being about 36 inches. Wheels  24  and  25  each ride on a 3{fraction (15/16)} inch shaft using spherical roller bearings (e.g, Browning SFC1000E by Browning Manufacturing, Emerson Power Transmission Corp., Maysville, Ky.). The horizontal position of idler wheel  25  is adjustable through blade tensioner  28 , which provides for increasing or decreasing the tension on blade  22 . Blade tensioner  28  is hydraulically controlled, but may also be mechanical, pneumatic, or the like. 
     Upper primary pinch roller  30  and lower primary pinch roller  32  apply pressure to the polymeric slab and operate to drive the slab through blade  22 . A second set of pinch rollers  31  and  33  (see FIGS. 9-10) is included between pinch rollers  30  and  32  and blade  22 . The two sets of pinch rollers operate to stabilize the slab and to keep the plane of the slab substantially parallel to the plane of blade  22  during slicing. Upper pinch rollers  30  and  31  are typically about 6 inches in diameter, made of steel, and covered with ruff grip top belting material to firmly grasp the workpiece. Lower rollers  32  and  33  are typically about 6 inches in diameter, made of steel, precision ground (because their dimensions determine the thickness variation in the final sheets—see below), and nitride coated for wear resistance and rust prevention. Rollers  30 ,  31 ,  32 , and  33  are hydraulically driven, but may be driven by mechanical, or other means known in the art. 
     Pinch roller pressure applicator  34  operates to put upper pinch rollers  30  and  31  into pressurized contact with the slab to force the slab against lower pinch rollers  32  and  33 , thereby keeping the slab stable as it passes through blade  22 . The preferred range of pressure applied to the slab by pinch rollers  30 ,  31 ,  32 , and  33  is from about 50 psi to about 100 psi, with a more preferred range being from about 70 psi to about 90 psi. 
     The thickness of the slices produced by saw  20  are determined by the vertical distance between blade  22  and lower pinch rollers  32  and  33  in the cutting area of saw  20 . In the current embodiment, the vertical position of blade  22  is fixed and the vertical position of lower pinch rollers  32  and  33  is adjustable; for best control over variation in thickness, finished sheets would therefore come off the bottom of the slab. The maximum standard deviation in thickness of finished sheets has been found to be about 0.002 inches. This level of precision cutting has never before been achieved with prior art band saws, and particularly in view of use with solid polymeric materials being sliced into relatively thin sheets over typical distances of about 36 inches to about 48 inches. The vertical position of lower rollers  32  and  33  is currently controlled by a mechanical adjustment, but such adjustment could be electronic, hydraulic, pneumatic, or the like. 
     Pneumatic switch  44  and pneumatic controls  46  operate pinch roller pressure applicator  34 , thereby raising and lowering pressure applicator  34  and controlling the amount of pressure that applicator  34  exerts on a slab during the slicing operation. Accumulator  48  operates to keep the tension on blade  22  constant during operation, by acting like a shock-absorber; if the blade is stressed during operation, accumulator  48  acts to automatically counter the stress and prevent breakage of blade  22 . Hydraulic controls  50  operate blade tensioner  28 , and the drive mechanism that turns pinch rollers  30  and  32 . 
     Dust collector  36  collects cutting debris, i.e. polymer chips, generated during the slicing operation. A coolant is used to cool, lubricate, and wash cutting debris from the slab and blade  22 . Referring now to FIGS. 7 and 8, coolant nozzles  52  bathe the slicing area of saw  20  with coolant before and after each blade guide  42 . The coolant may be water or a low viscosity lubricant. The coolant then drains out coolant drain  38  into coolant pan  40 , or more preferably through a recycling mechanism that filters the coolant and pumps it back onto the slab and blade  22 . Blade guides  42  maintain the vertical position and stability of blade  22  during operation of saw  20 . Blade guides  42  provide fixed position horizontal slits through which blade  22  travels during its cycle. Blade guides  42  may be made of ultra-high molecular weight polyethylene, brass which does not wear as fast as the polyethylene, or any similar relatively soft material. Blade rollers  54 , positioned as shown in FIGS. 7 and 8, maintain the horizontal position and stability of blade  22  during operation of saw  20 ; they are typically made of steel and provide back support to blade  22  as the workpiece is being pushed into and through blade  22 , thereby preventing horizontal deflection of blade  22 . 
     FIGS. 9 and 10 show feed conveyor  56 , which supports and feeds a workpiece into saw  20 , and back conveyor  58  which supports and takes up a finished workpiece after slicing (NJR Industries, Mobile, Ala.). These conveyors are made with ruff grip top belt material to prevent slippage during operation. Conveyor drives  60  operate movement and speed of conveyors  56  and  58 , and must be synchronized with the speed of pinch rollers  30 ,  31 ,  32 , and  33  so that a workpiece may be fed through saw  20  at a steady, uniform rate. The edge of a slab or workpiece is lined up against workpiece guide rollers  62  on top of feed conveyor  56  to insure that the longitudinal axis of the workpiece remains substantially perpendicular to the direction of travel of blade  22  during the slicing operation. FIG. 10 shows the position of a slab of polymeric material during the slicing operation. 
     Referring now to FIG. 9, the height of the top surfaces of conveyors  56  and  58  are adjusted so as to align with the tops of lower rollers  32  and  33 . This vertical position is set at some point below cutting level  64  on blade  22 ; level  64  corresponds to the lower vertical level of the cutting portion of blade  22 . For example, a typical distance between level  64  and the top level of alignment of rollers  32  and  33  and the top surfaces of conveyors  56  and  58  is about ⅛ inches. The speed of conveyors  56  and  58  and rollers  30 ,  31 ,  32 , and  33  is then synchronized to provide for uniform stable feed of the slab or workpiece through saw  20 . 
     The slab is then laid flat on the top surface of conveyor  56 , and the edge of the slab is positioned up against workpiece guide rollers  62 . Rollers  62  are positioned along one edge of conveyor  56  so that the longitudinal axis of the slab may be positioned substantially perpendicular to the direction of travel of blade  22  as the slab is fed into saw  20 . The slab is then fed forward into pinch rollers  30 ,  31 ,  32 , and  33 , which through pressurized contact hold the slab very stable and substantially parallel to blade  22  as the slab is fed into and passed through blade  22 . 
     Referring now to FIGS. 7 and 8, coolant from nozzles  52  is sprayed onto the cutting area to cool, clean, and lubricate blade  22  and the workpiece. Blade guides  42  stabilize the vertical position and blade rollers  54  stabilize the horizontal position of blade  22  as it passes through the workpiece. The sliced slab then passes through the back of saw  20  onto back conveyor  58  which transfers the sliced slab away from saw  20 . The main body of the previously sliced slab may then be run through saw  20  over again to produce another finished sheet, until the slab has been exhausted. 
     Additional advantages and modifications will be readily apparent to one skilled in the art, while falling within the spirit and scope of the claimed invention. The claimed invention in its broader aspects is not, therefore, limited to the specific examples and structures described above and claimed below. Any such advantages and modifications, while not specifically described and claimed herein, are deemed to be within the spirit and scope of the presently disclosed and claimed general inventive concept.