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Title:
IMPROVED METHOD AND APPARATUS FOR PREPARING CERAMIC BODY SEGMENTS
Document Type and Number:
WIPO Patent Application WO/2013/096113
Kind Code:
A1
Abstract:
A method including providing a ceramic log (300) with a first end and an opposing second end; providing one or more cutting devices (100) comprised of a dual bladed cutting member (200); and removing material by cutting at least the first end with the dual bladed cutting member (200), wherein a first blade (210) of the dual bladed cutting member (200) provides a finished surface and a second blade (220) removes a percentage of scrap above the finished surface. An apparatus (100) for cutting a ceramic log (300).

Inventors:
SCHUITMAN ABRAHAM (US)
VASQUEZ NESTOR (US)
STALDER BLAKE (US)
OGLE JAMES R (US)
SACCHETTI PAUL J (US)
Application Number:
US2012/069714
Publication Date:
June 27, 2013
Filing Date:
December 14, 2012
Export Citation:
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Assignee:
DOW GLOBAL TECHNOLOGIES LLC (2040 Dow Center, Midland, MI, 48674, US)
International Classes:
B28B11/12; B23D45/10; B23D53/00
Foreign References:
JPH06166017A1994-06-14
JP2003220605A2003-08-05
JP2007144922A2007-06-14
Attorney, Agent or Firm:
SIMS, Norman, L. et al. (Dobrusin & Thennisch PC, 29 W. Lawrence Street Suite 21, Pontiac MI, 48342, US)
Download PDF:
Claims:
What is claimed is;

Claim 1 ; A ceramic log cutting apparatus, comprising;

a nesting fixture for holding the ceramic log;

one or more cutting devices, the cutting device comprised of a motor and a dual bladed cutting member;

wherein a first blade of th dual o!aded cutting member provides a finished surface and an off-set second blade removes a percentage of scrap above the finished surface. Claim. 2; The ceramic log cutting apparatus according to ciairn 1 , wherein the off-set second blade has a kerf that allows for a percentage of scrap to be removed that is sufficient to prevent one or more defects proximate to an exit edge of tt e cut in the ceramic log.

Claim 3: The ceramic iog cutting apparatus according to claim 1 or 2 wherein the off-set second blade provides increased structural rigidity to the first blade.

Claim 4: The ceramic iog cutting apparatus according to any one of claims 1 to 3, wherein a leading edg of a cutting surface of the off-set second blade is at least 2mm inside that of a leading edge of a cutting surface of the first blade.

Claim S: The ceramic log cutting apparatus according to any one of claims to 4, wherein the kerf of the off-set second blade ranges between 4mm to 30mm,

Claim 6: The ceramic iog cutting apparatus according to any one of claims 1 to 5, wherein a leading edge of a cutting surface of the second blade is off-set inside that of a !aading edge of a cutting surface of the first blade a sufficient distance such that a sufficient amount of scrap is removed to prevent one or more defects proximate to an exit edge of the cut in the ceramic log.

Claim 7; The cerarnic log cutting apparatus according to any one of claims 1 to 6:

wherein the first blade comprises a first blade type and: the off-set second blade comprises a second: blade type<

Ciairn 8; The ceramic log cutting apparatus according to any one of claims 1 to 7, wherein the first blade type and the second blade type are identical.

Claim 9: The ceramic log cutting apparatus according to any ode of claims 1 to 8, wherein the first blade type is an abrasive saw.

Claim 0: The ceramic log cutting apparatus according to any one of claims 1 to 9, wherein the second blade provides increased structural rigidity to the first blade* Claim i 1 The ceramic log cutting apparatus according to any one of .claims. 1 to 10, wherein the second blade type is a serrated blade with a single sided set

Claim 12: The ceramic log cutting apparatus according to any one of claims 1 to it wherein the cutting device comprises a circular saw.

Claim 13; The ceramic log cutting apparatus according to any one of claims to 12, wherein the cutting device comprises a band saw*

Claim 14; The ceramic tog cutting apparatus according to any one of claims 1 to 13, wherein the cutting device comprises a reciprocating saw.

Claim 15: A method comprising:

providing a ceramic log with a first end and an opposing second end;

providing one or more cutting devices according to any one of Claims 1 to 14; and,

removing at rial 'by: cutting at least the first end with the dual bladed cutting member, wherein a firs blade of the dual bladed cutting member provides a finished surface and a second blade removes a percentage of scrap above the finished surface. Claim 16: The method according to Claim 15, wherein the ceramic log has a moisture content below 10 percent ..by weight or less.

Claim 17: The method according to Claim is or 8, further comprising the steps of removing material by cutting at least the opposing second end with the dual bladed cutting member.

Claim: 18: The method according to any one of Claims 1 S to 17, wherein the first end and: the opposing second end are cut concurrently with two dual bladed cutting members.

Claim 19: The method according to any Claims 15 to 18, wherein the ceramic log comprises a one or more honeycomb structures encased by an outer skin layer.

Claim 20: The method according: to any one of Claims. 15 to 19, wherein a center axis of the ceramic body and an axis of rotation of the dual bladed cutting member are laterally off-set no more than ½· the radius of the larger of the blades.

Description:
IMPROVED METHOD U APPARATUS FQSB PREPAftlNO CEBA iC BODY

SEQ EI fS IELD Ρ THE INVE TION

[001] The resent invention relates generally to a method and ap aratus for preparing one or more ceramic bodies (logs) with an improved end shap profile and to filters prepared from the ceramic bodies. More particularly, to a method and apparatus to cut one or more edge surfaces of the ceramic bodies down to a, desired segment length and providing an improved end shape profile,

BACKGROUND OF THE INVENTIO

fOOSj Diesel and gasoline engines emit soot particles, very line particles of carbon and soluble orgamos as well as typical harmful engine exhaust gases (i.e., . HG, CO and NOx). Regulations have: been enacted curbing the amount of soot permitted to be emitted. To meet thes challenges, soot filters constructed of ceramic bodies have bee used. In preferred embodiments, ceramic bodies that include an internal honeycomb structure and at least partially surrounded by a skin layer have been developed.

003j Manufacturing of these ceramic bodies has typically been accomplished via an extrusion process, wherein ceramic bodies are manufactured as individual logs of various lengths. It is also known that bonded assemblie of one or more individual logs are possible, for example as seen in US 6,869,751 , and incorporated herein by reference. The cutting of these logs into desired segment lengths, at a relatively high production rate and with minimizing defects, lias been the focus of on-going development efforts in industry. This is particularly true when the logs are in a softer state, commonly known as "green ware". Various cutting and grinding techniques and tools have been developed over the years, for example as disclosed in patent documents US 2007/0096370; US 7,452,263;. and US 2008/0233345, as well as numerous text books on the subject, such as Ceramic Technology and Processing, William Andrew Publlshlng/Noyes, King, A. G, (2002). Handbook of Ceramic Grinding and Polishing, Marfnescu, I D H. K. Tonsheff, et at (2000),· incorporated herein by reference. Each referenc teaches a different tool and/or technique to produce logs at a desired segment length. Th method of the present invention is not disclosed For example, some of the processes disclosed by the references may h limited in the amount of scrap (e.g. length) that can be removed in a single process step, which in turn may increas the time required to produce logs at a given desired segment length, in another example, it is suggested that scoring of the exit comer of the cut ' be .completed prior to cutting the log. Also,, it is believed that cutting techniques that utilize a singl blade, especially as it exits across the end of the work piece, can contribute to the creation of defects.

|0 4! Defects in the e d surfaces of the log may foe defined broadly as an abnormality in the surface, More explicitly, defects may include- cracks or chips (typically greater than about O.Smm) in the outer skin layer and/pr missing, damaged, or deformed honeycomb walls,

[005] What is needed are processe and fools for preparing ext uded ceramic body segments, at commerciall acceptable rates/ to desired: segment lengths without a signif icant number of defects I the end surfaces (e.g, the outer skin layer and/or th honeycomb structure), that allow for greater flexibility as to the amount of scrap (e.g. length) that can be removed in a. single process step,

■SUMMARY OF THE I VE TION

[006] Th present invention addresses is focused on a: new and Inventive wa to produce: ceramic logs at. a desired segment length, in a relatively short process cycle time,, ail while minimizing defects. The presen invention disclosed herein ma be generally described as a method and/or an apparatus that Includes -cutting, device with a dual bladed cutting member thai simultaneously provides a "finished surface" for the log and removes scrap from above the finished surface,

00?1 i : n. one aspect of the present invention, the dual biaded cutting member may be comprised of two copianar blades that have off-set cutting surfaces (off -set relative to each other parallel to its cutting: direction). The off-set may be at least a sufficient distance such that a sufficient amoun of scrap is removed to prevent one or more defects proximate to an exit edge of the cut in the ceramic log, it is preferred that the offset be at least about 2.0mm, although other off-set values may be desirable depending on other factors, such as type of cutting device, size of the ceramic Sog s and/or size of the cutting member (e,g. particularly in the case of a circular saw). It is also contemplated that this cutting member be part of a larger cutting apparatus.

|008] In one aspect of the present invention, a defect may be further defined as an imperfection in an outer wall of the log or in any internal structures (e.g. honeycom wails). Of particular interest are when there are more than one of these defects that may ¬ be caused by a cuffing process and are generally proximate to (e.g. within about ,20mm} an exit edge of the cutting surface. More particularly, when the defect{s) are about 1mm otmore in depth,

fSOSj In another aspect of the invention, the dual blasted cutting member may comprise two distinct biade types. It is contemplated thai s at least one preferred configuration, the first blade comprises an abrasive biade and the second comprises a blade that removes scrap, The abrasive blade may be a diamond grit blade and he second biade is a serrated blade, preferably a carbide lipped blade,

[0010] in another aspect, the ceramic log that is to be cut in ibis inventive method/apparatus may have a relatively low moisture content (e.g. amount of water or other applicable liquid medium), in at least on© preferred configuration, the log's moisture content is no more than about 10 percent (by weight), more preferably iess than about S percent, and most preferably less than about 2.S percent.

[OOif] The invention constitutes a new and Inventive way to produce logs at a desired segment length, in a relatively short process cycle time, all while minimizing defects. It should be appreciated that the above referenced aspects and examples are non-iim iting, as others exist within the present invention, as shown and described herein.

DESC IPTIO OP THE PSM INSS

[0012] Figure 1 illustrates the. relationship of a blades of the cutting apparatus with respect to a ceramic log to be cut.

[S013] Figures 2 A to 2F illustrate defects thai can result from ceramic log cutting processes,

[001 ] Figure 3A illustrates differences in orientation of a cutting blade to a ceramic log between passing through a ceramic log to be cut the centerilne of a blade, cutting direction:, arid ' a portion of the blade below the centerline,

S| Ftgu re 38 is a bar chart of the results of Example 3 ,

fO01@3 Figure 4Λ shows a cutting apparatus of the invention with a ceramic log disposed thereupon,

[0G17J Figure 48 shows a cutting blade of the apparatus passing through a ceramic log.

100183 Figure 5 is a cSiart showing the results of the Comparative Example. DETAILED DESCRIPTION

[0019] The explanations and illustrations presented herein are intended to acquaint others skilled In the art with the invention, its principles, and its practical application. Thes skilled in the art may adapt and apply the invention in its numerous forms, as may be best suited to the requirements of a particular use, The specific embodiments of the- present invention as set forth are not intended as being exhaustive or limiting of the invention. The scop© of the invention should be determined with reference to the a ended eiai s, along with the full scop of equivalents to which such claims are entitled. The disclosures of all articles and references, including patent ■applications and publications, -are ' incorporated by reference for all purposes. Other combinations are also possible as will be gleaned from the following claims, . which are hereb incorporated by reference info this written description.

[002SJ The invention relates to a method comprising: providing a ceramic log with a first end and an apposing second end; providing one or more cutting devices comprised of a dual bladed cutting member; and: removing material by cutting at least the first end with the dual bladed cuffing member, wherein a first blade of the dual bladed cutting member provides a finished surface and a second blade removes a percentage of scrap above the finished surface.

[00213 in another aspect the invention relates to a ceramic fog cutting apparatus, comprising: a nesting fixture for holding the ceramic log; one or more cutting devices, the cutting device comprised of a motor and a dual bladed cutting member; wherein a first blade of th dual bladed cutting member provides a finished surface and an off-set second blade removes a percentage of scrap above the finished surface.

|O022] The invention may be further characterized- by one or any combination of the features described herein, such as; the percentage of scrap removed by the second blade is sufficient to prevent one or more defects proximate to an exit edge of the cut in the ceramic log; the one or more defects proximate to the exit edge of the cut comprises an area of ceramic material that is missing from the finished surface; the one or more defects proximate to the exit edge of the cut comprise at least one chi with a depth of at least 1 mm.; the second blade provides increased structural rigidity to the firs! blade; a leading edge of a. cutting surface of the second blade is off-set inside that: of a leading edge of a cutting surface ' of the first blade a sufficient distance such that a sufficient amount of scrap is removed to prevent one or mor defects proximate to an exit edge of the out In the ceramic log;, the second blade is off-set at least 2mm inside that of the leading edge of the ' cutting surface of the first blade; the first blade comprises a first blade type and the off-set second blade comprise a second blade type; the first blade type and the: second blade typo are identical: the first blade typo is an abrasive saw; the second blade type is & serrated blade with a single sided set; the serrated blade has a kerf that ranges between 4mm to SOnim; the ceramic log has a moisture content below 1Θ percent; the ceramic log has a moisture content below 0 percent; the ceramic log has a moisture content belo ,5 percent; comprising the steps of removing material by cutting at least the opposing second end with the dual hladed cutting member: the first end and the opposing second end are out concurrently with two dual bladed cutting members; the cutting device comprises a circular saw; the cutting; device comprises a band saw; the cutting device comprises a reciprocating saw; the ceramic log comprises a one or more honeycomb structures encased by any outer skin layer; the one or more defects proximate to the exit edge of the cut comprise an area of honeycomb wall detachment from the outer skin layer and/or other honeycomb structures; the ceramic log comprises green ware; and th ceramic log comprises mullite. oordierlfe, SiC or mixtures therein,

[8023] The present invention relates to an Improved method and apparatus for the preparation of ceramic products (!ogsj at a desired segment length, In a relatively short process cycle time, all while minimizing defects, defects particularly at or proximate to the exit edge of the cut

Ceramic Products

[0024] Ceramic products (and ultimately ceramic foodies or logs) are generally prepared by multi-step process. Generally, the process begins by contacting one or more precursors for the ceramic structure, ceramic precursors, optionally: one or more binders and one or more liquid carriers. The next step generally includes the formation of the desired shape, which can be completed by numerous shaping processes, but most commonly by extrusion, then cut to a nea net dimension (e.g. length, width, thickness) bef ore the next processing step. The product typically is then dried to a point where the moisture content ranges from about 0 to 0 percent. If is at thi point whore the inventive metno apparaius ma be used (although it is contemplated that the inventive method^apparatus can be used on ceramic products that have been further processed). After the product Is cut to a "finished" length, then it may be further processed {e,:g.

S plugged, calcined., muliifeed, etc,}.. Additional details on these steps are disclosed in the following paragraphs,

[O025J The ceramic precursors are generall the reaefants or components which when exposed to certain conditions form a ceramic bod or part, which may include materials such as disclosed in US 7,485,594; US 6,953,554; US 4,948,768 and US 5, 73,349 all incorporated herein by reference, for example a porous rnuiiite composition made by forming a mixture of one or more precursor compounds having the elements present in muH ' ite (e.g.,. clay, alumina, silica) and a property enhancing compound. The property enhancing compound may be a compound having an element selected from the group consisting of Mg, Qa, Fe, Na, , Ce, Pi, Nd ^ /Sm, Eu, Gd, Tb, Dy Mo, Er, Tm, Yb, ty, B, Y, Sc, La and combination thereof. Also a ceramic precursor comprising silicon carbide * eordiente, aluminum fit&nate, alumina, zirconia, silicon nitride, aluminum nitr de^ silicon ©xynifrlde ¾ silicon carbonithde, beta spodumene, strontium aluminum silicates, lithium: aiuminurrv silicates, and the like. Organic binders useful in this invention include any known materials which render the wet ceramic green ware shapeable. Preferably, the binders are organic materials that decompose or burn at temperatures below the temperature wherein the ceramic precursors react to form ceramic bodies or parts. Among preferred binders are those described i introduction to the : Principles, of Ceramic Processing, J. Reed, Wiley interscience, 1988} incorporated herein b reference. A particularly preferred binder is methyl cellulose (such as jETHOCEL A15LV .methyl cellulose, The Dow Chemical Co., Midland, Mich.), Liquid carriers include any liquid that facilitates formation of a shapeabie wet ceramic mixture. Among preferred liquid carriers (dispersanis) are those materials described In introduction to the Principles [ Of Ceramic Processing, J. Reed, Wiley interscience, 1988). A particularly preferred liquid carrier is water. The: mixture useful in preparing wet ceramic green ware bodies may be made by an suitable method such as those known in the art. Examples include bail milling, ribbon blending, vertical screw mixing, V-biending and attrition milling. The mixture may be prepared dr (i.e., in the absence of a liquid carrier) or wet. Where, the mixture ' is prepare in the absence of a liquid carrier, a liquid carrier is added subsequently utilizing any of the methods described in this paragraph,

[0026] Th mixture of ceramic precursors, optionally binders, and liquid carriers may be shaped by an means known In the art, Examples include ' injection molding, extrusion, rsostatie pressing, slip casting, roll compaction and tape casting. Each of these is described in more detail in introduction to ihe Principles of C&mmic Processing,

8 J. Reed,, Chapters ' ' 20 and .21, . . VVISe infarselenee, 198S, incorporated herein by reference, in a preferred embodiment the mixture is shaped into the near net: shape and size of the ultimate desired ceramic bod < such as a flow through filter. Near net shape and size means the size of the wet ceramic green ware . ody may be within about TO to 15 percent by volume of the size of the final ceramic body; * and preferably the size and shape may be within 5 percent by volume of the size of the final ceramic body. In one preferred embodiment the ceramic structures comprise a -honeycomb structure and an outer skin layer. Preferably the honeycomb structure is disposed In planes perpendicular to the extrusion direction. The outer skin layer and the walls of the honeycomb structure generally have a thickness of between about .250 and 600 microns, although structures with thicknesses of u to about 50 percent larger or smaller are contemplated. In use, each channel formed is plugged at one end or th other. On a face the channels are plugged in an alternating fashion. Preferably the wet ceramic green ware body does not have any of the channels or flow passages blocked or plugged, in practicing: the invention, the porous, ceramic honeycomb as well ' as the plugs (note, the plugs may be the same or a different ceramic than the honeycomb as well as may simply be fhe : partition wails of the honeycomb pinched together to close off a channel) may he any suitable ceramic or combinations of ceramics,

[0027] In a. preferred embodiment the wet ceramic g een ware body is shaped such that st can be utilized as a flow through filter. At this stago in the process the wet ceramic green ware body has tw opposing faces which ar substantially planar. The wet ceramic green ware body exhibits a cross sectional shape which is consistent for all planes parallel to the two opposing faces. The cross-sectional shape can be any shape which Is suitable for the intended use and may be Irregular or may be of an known shape, such as round oval or polygonal. Preferably the cross sectional shape exhibits a flat surface capable of supporting the ceramic body, Preferabl the cross-sectional shape is polygonal * in one preferred embodiment, the shape is rectangular or square. If the shape is i egular, it must have at least one linear path or one surface that is planar such that the wet ceramic bod can be disposed on the carrier ' on the linear path or planar surface. he wet ceramic green ware foody has a plurality of walls formed which extend from one opposing face to the other opposing face. The walls form a plurality of flow passages that extend from one opposing face to the other opposing face. Preferably, at. this stage, all of the flow passages are open to both opposing faces. This allows more efficient removal of liquid carrier. Thereafter the. wet ceramic green ware body is subjected to conditions to remove the liquid carrier, thai is to dry the wet ceramic green ware body, preferably to a point where t e moisture content is about 10 erc nt or less, more preferably about 5 percent or less arid: most preferably about 2.5 percent or less. Preferred drying methods are described In co-owned co-pending application lifted "DRYING: METHOD FOR CERAMIC C3REE WARE" filed June 22, 2011 Serial Number 13 168,298· and filed in the PCT June 22 » 201 1 application number PCT/US/11/41410 both incorporated herein by reference,

[0028 j After removal of the liquid carrier from the wet ceramic green ware body, th ceramic green war body can be prepared fo conversion to a ceramic body* and wherein the present inventive process/apparatus is most likely utilized, by cutting the bod (log) to a desired length- (although present Invention may be equally effective when the ceramic Is furthe cured or mui!itized}. ter utilizing the inventive ' method/apparatus disclosed herein, the ceramic green ware bod is exposed to conditions to burn out the binder and to form the ceramic structure. Processes to achieve this are well known in the art. The dry ceramic green ware parts are calcined by heating the dry ceramic green ware parts to temperatures at which organic additives and binders are-: volatilized- or burned away. The parts are further heated to temperatures at which the ceramic particles fuse or sinter together or create new particulates that subsequently fuse together. Such methods are described by numerous patents and open literature i cludi g * for example, US 4,329,162; 4,471 ,792 4,001 ,028; 4,182,285; 3 S 8$$,326; 4,786,542; 4,837,943 and 5,538,681; all incorporated herein by reference.

p32SJ It is contemplated that the present invention may be applicable to any porous particulate bodies, Most prefereabSy to green ware, debindered greenware, and even calcined where particulates are fused but later fused or reacted to form stronger body,

[0030] It is contemplated that a "defect" as If relates to the present invention may be broadly defined as a surface irregularity on: or near the end surface of the cut log. This surface irregularity may be in the wails of honeycomb structure, in the outer skin layer, or both. Illustrative examples are show in Figs. 2A-F, where "chips" of the outer skin layer are missing ami/or where parts of the honeycomb wail are absent. In one embodiment, a defect may fee defined as surface irregularity that causes problems with the downstream processing of the part, for example preventing the honeycomb, channel from being plugged. In a preferred embodiment, the defect may be defined as at least, one chip with a depth of at least 1mm (dept -from the finished surface) at or near (e.g. -with about 25mm) the exit edge of the cut.

Qjttjng Device

0031] A cutting device and method is provided that Is capable of cutting ceramic bodies:, and more preferably wet (e.g, containing less than about 10% liquid by weight) ceramic green ware bodies, to a desired dimension (e.g. length), while maintaining o creating an acceptable surface -finish ' on the part. It is also contemplated that the cuffing process should be relatively quick " , for example it should be able to cut the ceramic body to a desired length in less than about 2 minutes, and preferably less than about 20 seconds, and preferably greater than about 5 seconds (too fast may damage the body), ft is also preferred that it should only take one cutting pass (per end) to achieve the desired length and surface finish. In one preferred embodiment, the scrap materia! removed from the end being cut is sufficient to prevent one or more defects proximate to an exit edge of the cut in the ceramic log.

[0032] It is contemplated that the: travel across the body being cut at a preferred range of speeds from about 10 to 40cm/minute, In the case of a circular saw configuration, the rotation of the blade may vary from as low as about 500 rpm to as high as about 3000 rpm or higher. I a preferred embodiment, the rotation is about 750 to 2500 rpm, and mora preferably about l OQQ to 2000 rpm. In the case of a band or reciprocating saw, the linear movement of the blade Is in terms of meters per minute (m/min). It is contemplated that this could range from as low as about 900m/min to as hig as about i*000m/min. Preferably, the linear movement of the blade Is about 1 SOOm/min to about 17£K5m min s and more preferably from about " 600m7min to 1700m min>

IS033J The cutting device may be included: ' in a ceramic log cutting apparatus. The: apparatus may include a nesting fixture that functions to hold the ceramic part. It may also -include a power source (e.g. motor) thai functions to move the cutting devloe(s).. It may also include one or more cutting devices, for example cutting devices disposed a distance apart from each ether such that each device can cut opposing edges of the ceramic part either simultaneousl or in close temporal proximity.

[0034] The cuffing device may fee configured in many different forms. Functionally, the device both removes an amount of the log (e.g. scrap) and provides a relatively defect free end surface (e.g. one: or less chips). The device may be In the form of a circular saw, a band saw, or a reciprocating saw. No matter the form of the cutting device;, the device should be configured to have two or more cutting surfaces that are. immediately adjacent (e.g. with about 10mm) to one another or are in- contact.

[003S] The cutting: de ic preferably consists of a. dual bSaded cutting member, where one blade functions to directl cut the finished surface of the log and a second blade that functions to aid in the removal of the scrap material. These two blades may abut one another along one plane (or ma be spaced apart as much as about iOrrsm) and are preferably off-set along the cutting surface, it is preferred that a leading edge of a- cutting surface of the second blade may be off-set inside that of a leading edge of a cutting surface of the first blade a sufficient distance: such that a sufficient amount of scrap is removed to prevent one or more defects proximate to an exit edge of the cut in the ceramic log. in one preferred embodiment, the second blade is oft-set about 2.0mm or mo ,, more preferably about 5.0mm or more, most preferably about 12.5mm or more, and off-set about SO.O im of less, more preferably about 45mm or less, most preferably about 40,0mm or less, all inside the leading edge of the cutting surface of the first blade.

[00361 The blades may comprise the same or different blade types, so long as they provide the functionaliti? discussed within this disclosure. In one embodiment the blades consist of the same type of blade. In another embodiment, the blades ana two different types. The type of blades useful include for example, abrasive saw blades and serrated saw blades. An abrasive saw b!ade is similar to a thi grinding, wheel, and a serrated saw blade is a blade with a cutting edge that has many small points of contact with the material being cut.

10037] in a preferred embodiment, the blades are different types, wherein the first blade is an abrasive blade and the second blade is a serrate blade, !vsore particularly, the abrasive blade comprises a diamond grit blade and the serrated blade: is a carbide tipped blade, and more particularly a blade with a single sided set.

00381 In one preferred diamond grit blade embodiment, the blade ma comprise a grit rating that ma range from as iow as 40/80 to as high as 200/220 and: stiSi may perform as required. Functionally, the grit value should be appropriate to cut the tog without creating excessive defects, If is believed- that the highe the grit value: (e.g. the finer the abrasive), the better the chance to have a defect free cut, but the higher the chance that the blade will become clogged soone and would have to be cleaned ("dressed") more often than would be desired, particularly in a production environment It is believed that there is a relationship between the: moisture content of the log and: the limit on how high a grit value that can be used. In one preferred embodiment, a grit value of about BO/80 or less may be used ©n logs with a moisture content below about 10 percent: by weight or less,, more preferably a grit value f about 100/120 or less on logs with a moisture content below about $ percent by weight or less, and most preferably a grit value of about 200/220 or less on logs with moisture content below about 2.5 percent by weight or less.

[0030] In one preferred serrated blade embodiment, the cutting member has a kerf that is about 2mm or more, more preferably about 4mm or more and roost preferabl about 7mm or more, It is also preferred that the kerf Is about 50mm or less . ,, more preferably about 40mm or less, and most preferably about 30mm or less.

fCH O] Preferably the blades provide complementary structural reinforcement o increased structural rigidity, particularly in the case where the two blades abut one another along one plane. The blades in combination provide sufficient stillness to reduce or eliminate any deflectio that may induce defects. In a preferred embodiment, the two blades together are at least 100% more-stiff than if the blades were not together. This ma function to allow the blades to be run while preventing excessive movement or flexing that could cause surface defects onlhe ceramic part,

£00 11 in one preferred embodiment, the device is a circular saw, where the device includes dual blades that rotate irV the same direction about a central axis. It is preferred that the dual blades abut one another in one plane and have cuffing surfaces that are radially off-set (a first larger and a second sfnat!e blade), it is contemplated: that the diameter of the blades should be larger than the cross length of the ceramic body to be cut. In one preferred embodiment the blades diameter is sufficientl large such that it cuts the: log in one pass. Preferably, the blade diameter Is at least about 240 percent or more larger than the cross length: of the ceramic body (e.g. area to be cut),, more preferably about 300: or more, and most preferably about 385 or more;: and at most about 600 percent: larger, more preferably at most about 500 larger, and most preferably: at most about 420 larger.

[0042] it is also preferable that all of the cross length of the ' ceramic body be positioned ' well inside the blade diameter. In other words, the center of the ceramic body should be proximate to the axis of rotation: of the circular blade. Preferably,, the center axis of the ceramic body be the same as that of the axis of rotation of the circular blade or laterally off-set at most about ½ the radius of the larger first blade, more preferably no more than about 1/3, and most preferably no more than about ,14, - An: llustrative ' example (Example No. 3) is provided below. Figure: 3Ά shows the axis of rotation 400 (center of blade in the cutting direction) with respect to two orientations of the ceramic body with respect to the blade.

pH 3]j Preferably a method of cutting,, given the above details and the examples below, includes at least the steps of: providing a ceramic log with a first end and an opposing second end; providing one -or more cutting devices comprised of a dual bladed cutting member; and removing material by cutting at least the first end with the dual biaded cutting member, wherein a first blade of the dual bladed cutting member provides a finished surface and a second blade removes a percentage of scrap above the finished surface.

[0044]: Preferably, the percentage of the scrap removed by the second blade is sufficient to prevent the defects discussed in this application. A the blades move across the log, making the cut, the second blade removes, a percentage the scrap from above the first blade. This should help reduce the occurrences of defects by removing the mass of the scrap and the potential deleterious effects the presence of the scrap may have on the log walls (internal, ψ external -wails) before fhe : first blade nears (or reaches) the exit edge of the cut. in a preferred embodiment the second biade removes at least about 50 percent of the scrap, more preferably at least about 80 percent, most preferably at least about 70 percent of the total scrap, and at most about 95 percent, more preferably at most about 90 percent, and most preferably at most 85 of the total scrap before the first blade nears (or reaches) the exit edge of the cut.

JQ045J There Is a relationship between the kerf of the serrated biad and the position of the cut being made below the end of the log. The distance 'TF, is the distance from the end of the uncut log to " the finished cut surface. It is preferred that "D" b small enough so the cutting member can effectively remove the scrap and prevent defects in the log from the cutting, but large enough allow for the process to require only one cot per side. Preferably, "D" is about 0.5 times to about 3.0 times the kerf of the second blade, more preferably about 0.75 times to 2,0 tiroes and most - preferably about 1.0 to 1.5 times the kerf.

illustrative Emb©fillr«ertt¾ &f t e Invention

[0046] The following examples are provided to illustrate the invention, but are not intended to limit th scope thereof. Any dimensional information used in these exam pies should not be considered limiting and it is contemplated that the ceramic parts and cutting devices could be significantly smaller or larger. Example : Circular Saw 2 O

{0047} As an illustrative example, as shown in Figures 1 s 4A and 48, a circular saw style ceramic log cutting apparatus 100 is presented. The apparatus 1.00 includes a dual bladed cutting member 2O0 f a ceramic log 30O, : a nesting fixture 110, and motors (not shown) that drive the member 200.

£0048] The dual bladed ■■ cutting member 200 In this example consists of a first blade 210 and a second blade 220 abutting one another, as illustrated in Figure 1. In this example, the first blade 2 0 is circular ' blade with a diameter of about 16 n (408mm) and the second blade with a diameter of about 15.0in. (381 mm). Both blades rotate about a common axis 9in the same direction) and a leading edge 222 of the cutting surface of the second blade 220 is off-set inside that of a leading edge 212 of the cutting surface of the first: blade 210 by about O.Sin, (12.5mm). Blade 210 is. an abrasive saw, in this example a .diamond grit blade (O.OSOin, (1 ,3mm}:) core thickness and an 80/100 diamond grit) and blade 220 is a serrated blade with a single sided set, more specifically a carbide tipped blade (0,12Sln. kerf (3,2mm)},

00493 The member 200 is rotated at a rate of about 500rpm and feed into the log 300 at a rate ranging from about 10 to 40cm/minute to perform the cutting of the log 300, The cut is made below the end of the log: a distance that Is equal to or as much as 1.5 times the kerf of blade 220.

Example 2; Band Saw/Reciprocatina Saw 500

[0050] As another illustrative example, a band saw/reeiproeating saw style ceramic log cutting apparatus 100 is presented. The cutting member 600 is similar to thai presented In the circular saw example above in that leading edge 522 of the cutting surface of the second blade 520 is off-set inside that of a leading edge S12 of the cutting surface of the first blade 510 by about O.Sin, ( i.2..5mm). Blade 510 is an abrasive saw, in this exampie a diamond grit blade (O.OSOin, (1 ,3mm)) core thickness and an 80/100 diamond grit) and blade 620 is a serrated blade with a single sided set, more specifically a carbide tipped blade (0.125in, kerf (3.2mm)), The member doe not rotate, but has a linear motion (one direction for th band saw and two fo the reciprocating saw of about 1 OOm/minute and feed into the log 300 at a rate: ranging from about 10 to 40cm/minute to perform the cutting of the log 300. |0051j In an illustrative example two circular saw style ceramic log cutting methods are presented, in a first set-up (YL1 1), a log 300 is placed such that the bottom of fee log 300 is -disposed nearer the bottom of the circular saw 600. I a second set-up (YI14),. the log 300 is placed such that it is nearer the axis of rotation of the saw 600, both setups as shown in Figure 3A, Two group of seven logs 300 each are processed as described in example 1 above, with the location of the log 300 relative to the axis of rotation of the saw 600 being different for each group. Table 1 shows the result and illustrates thai the average yield of "defect tree" parts is significantly higher when the log is: nearer to the axis of rotation of the saw 600, Figure 38 is a bar chart of the results from Table 1.

Table 1

[0052] Examples are run between a dual blade member 200 and three single blade configurations, in set-up number one, a single blade with a 0,055" core thickness and an 80/100 diamond grit is used, set-u numbe two-, a single blade with a 0.040 * core thickness aa a 80/80 diamond grit is used, set-up number three, a single blade with a 0.040" core thickness and an 80/100 diamond grit is used, and in the fourth set-up, a dual blade as described in Example 1 is used). The various blade configurations are defined in labia 2 belo The blades are rotated at a rata of about ISOQrpm and feed into the logs 300 at a rata ranging from about 10 to 40cm/rrnnute to perform the cutting of the log 300> At feast 2000 logs 300 are cut in each set-up and the resulting percent of defect free logs is presented in Fig * 8. A defect being defined: as at: least two chips with a depth of at least im at or near (e.g. with about 25m m) the exit edge of the cut. Using Tukey- ranier method (Tuiie -Kraraer method is a single-step multiple comparison procedure and statistical test gen ally used in conjunction with an AN OVA to find which means are significantly different from one another) it s shown that the inventive dual blade approach produces a significantly larger percentage of acceptable ("prime") parts or segments. The results are shown in the chart of Figure 5. The circles on the right of the chart show the range of results for each blade configuration.

Tabie S

|0053] Unless stated otherwise, dimensions and geometries of the various structures depicted herein are not intended to be restrictive of the invention, and other dimensions or geometries are possible. Plural structural components can be provided by a single integrated structure. Alternatively, a single integrated structure might be divided into separate plural components. In addition, while a feature of the present invention may have been described in the context of only one of the illustrated embodiments, such feature may be combined with one or more other features of other embodiments, for an given application.. It will also be appreciated from the above that the fabrication ¥ the unique structures herei and the operation thereof also constitute methods in accordance with the present invention. 0QS4J Any numerical values recited in the above application include ail values- from the lower value to the upper value in Increments of one unit provided tha there is a separation of at least 2 units between an lower value and any higher value:. As an example, if it is stated that the amount of a com onent or a value of a process variable: such as, for example, temperature,, pressure, time and the like is, for example, from 1 to SO. preferably: from 20 to 80, more preferably from 30 to 70, it is intended that values such as 16 to 85, 22 to 68, 4-3 to 6i , 30 to 32 etc, are expressly enumerated in this specification. For values which are less than, one, one unit is considered to be : 0.0001 , 0.001, 0.01 or 0,1 as appropriate. These are oniy examples of what Is specifically intended and all possible combinations of numerical values between the lowest valu and the highest vaiue enumerated are to be considered to be expressly stated i this application in a simila manner. The term "consisting essentially of to describe a combination shall Include the elements, Ingredients, components or steps identified:, and such other elements ingredients, components or steps that do not materially affect the baste and novel characteristics of the combination. The use o the terms "comprising" or including" to describe combination of elements, ingredients, components or steps herei also contemplates embodiments that consist essentially of th elements, ingredients, components or steps. Plural elements, ingredients,: components or steps can be provided b a single integrated element, ingredient, component or step. Alternativel , ¾ single integrated element, ingredient, component or step mig t be divided info separate plural elements, Ingredients, components or steps, Th disclosure of or "one" to describe an element, ingredient, component or step is not intended to foreclose additional elements, ingredients, components or steps, Uniess otherwis stated, ail ranges include both endpoints and all numbers between the endpoints. The use of "about" or "approximately" in connection with a range: applies to both ends of the range. Thus, "about 20 to 30" is intended: to cover "about 20 to about 30", inclusive of at least the specified endpoints.

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