Patent Application
20150104262
(1) Field of the Invention
This invention relates to devices for mechanically removing material from a workpiece or bulk feedstock, creating chips of removed material while producing a new surface on the workpiece or bulk feedstock.
(2) Description of Related Art
Machining processes are a subset within the broader realm of manufacturing processes where machining processes involve the separation of material from its parent piece. Generally, machining processes fall into classifications of “traditional”/“conventional”, whereby the material is removed through the application of mechanical energy to push one or more cutting teeth through the material to remove a layer of material from the parent piece, and “non-traditional”/“non-conventional”, whereby material is separated from the parent piece with either very limited or usually no mechanical energy, using instead thermal and/or chemical energy. Some examples of non-conventional machining processes include laser cutting/machining, electro-discharge machining (EDM), and electrochemical machining (ECM). Some examples of conventional machining processes, presented based on the types of surfaces they create, include:
Creation of two generally planar surfaces through use of a sawing process, where the saw blade is either translated in a plane that is parallel to the two surfaces being created or rotated about a spindle axis that is normal to the surfaces being created.
Creation of a surface that is externally or internally axisymmetric, through the use of, respectively, a turning or boring process, where the workpiece is rotated about a spindle axis that is coincident with the axis of said axisymmetric surface.
Creation of a surface that is internally cylindrical through the use of a cylinder boring or drilling process where, respectively, the boring bar or drill bit is rotated about a spindle axis that is coincident with the axis of said cylindrical surface.
Creation of a surface that is a substantially flat through the use of a face milling or end milling process where the milling tool is rotated about a spindle axis that is either normal to or parallel to said flat surface.
Creation of a surface that is three-dimensional or sculptured through the use of a milling process where a bull-nosed or ball-end milling tool is rotated about an axis that is either normal to or at a variable angle to said sculptured surface.
Processes such as grinding, lapping, and honing, whereby a relatively small amount of material is removed through mechanically working small grits of abrasive material over a surface, may also fall in the conventional machining processes classification in the sense that a relatively thinner layer of material is removed, though these processes focus on finishing a surface to a desired texture and are not generally used to change the gross shape/geometry of the surface. In other words, a machining process aims to create a new and generally different, more usable surface by removing material. The removed material is generally referred to as a “chip” and, along with worn out cutting tools, is a byproduct of the machining process.
Another set of processes that remove material from a parent piece is referred to as reduction processes. The similarity of reduction processes to conventional machining processes is that material is removed through the application of mechanical energy to push one or more cutting teeth through the material to remove a layer of material from the parent piece. Some terms often used to name specific reduction processes include chipping, chopping, shredding, grinding and milling, grinding and milling here being very different than grinding with abrasive grits and face milling or end milling noted earlier in that in the case of reduction “grinding and milling” generally involve brittle fracture of material through repeatedly smashing, crushing, and/or impacting with a blunt instrument/tool upon larger particles until a desired particle size is reached. The stark contrast is that in reduction processes the “chips” or particles that are formed are the desired product, not the byproduct (however, worn out tools are byproducts in common with machining processes). As such, the focus in reduction processes is on the chip/particle produced and not the surface that remains on the parent piece (bulk feedstock), and furthermore the objective in reduction processes is to fully consume the parent piece by converting it in its entirety into chips/particles, whereas in machining processes the objective is to retain a substantive amount of material in the parent piece, usually called the workpiece, which is ultimately intended to serve a function as part of a manufactured product.
Put another way, in order to focus on the precise purposes and desired products of conventional machining versus reduction processes, conventional machining processes make use of cutting teeth on or affixed to cutter bodies where the primary purpose is the removal of material from a workpiece, being either raw stock or material that has been previously worked into an intermediate surface finish, shape, and size, so that the new surface created on the workpiece is either a final surface having the final desired surface finish, shape, size, and/or position relative to other geometric feature(s) on the workpiece, or is an intermediate surface produced enroute to achieving through subsequent use of this or other manufacturing processes the final surface of desired surface finish, shape, size, and/or position relative to other geometric feature(s) on the workpiece. In conventional machining processes, either the cutter body or the workpiece may provide the cutting motion, usually by way of relatively high speed rotation of the cutter body or the workpiece. In contrast, reduction processes make use of teeth affixed to either a drum or disc that is rotated at relatively high speed to provide a cutting motion where the primary purpose is to reduce feedstock material pieces, in their entirety or to the extent possible given requirements for holding and supporting the feedstock material pieces, from their relatively large size into particles of relatively smaller size either with or without regard to the shape and/or size of the particles.
Some examples of reduction processes, presented based on the types of feedstock they reduce, include:
Depending on the industry and/or the type of feedstock and/or the type of removal mechanism (sharp-edged cutting versus tearing apart versus blunt fracture), the processes go by various names such as but not limited to chipping, chopping, grinding, shredding, granulating, and milling. In fact, the use of some of these names at some times is not necessarily a very precise picture of the removal mechanism. For example, machines used to reduce plastics in the process of recycling are often called grinders or granulators, the latter generally producing more consistently and smaller-sized particles, whereas in fact they both work using sharp-edged teeth that cut through the material at high speed without use of crushing as is the case for “grinders” in other industries, and these are in contrast to shredders that operate at low speed and tear apart the plastic into more random sized and shaped particles/pieces of relatively large size (e.g., one or more inch versus fractions of an inch). Examples like chipping of woody biomass and chopping of grassy biomass are well reflective of the reduction mechanism (sharp-edged cutting).
Reduction machines of interest for the present invention generally operate at high speeds and involve the mechanism of sharp-edged cutting rather than tearing apart or blunt fracture. They have an opening to the reduction chamber through or into which feedstock is fed/pushed. The feedstock then encounters a rotating drum or disc to which multiple teeth are affixed. The feedstock is supported on the side opposite the direction of approach of the tooth by an anvil surface. Each tooth, as it rotates past the feedstock, encounters the feedstock making contact with the feedstock to form one or more chips/particles. The machines on which reduction processes take place go by various names. Brush chippers and whole-tree chippers are generally used to chip woody biomass by feeding the wood material horizontally into the machine; the machine uses very wide teeth, typically referred to as knives, affixed to a drum or disc. Other machines, referred to as horizontal grinders or recyclers, are fed horizontally and employ a drum affixed to which are teeth that are generally axially shorter than the aforementioned knives. Another type of machine is a tub grinder which is fed vertically by depositing the feedstock into a large tub in which teeth are affixed to a rotating disc/ring, and generally employ a tearing mechanism; unlike the others of interest these tend to operate at low speeds. The term rotary shredder is used for machines in the paper, plastics and whole-products recycling industry. Then again, what was referred to as horizontal “grinders” are referred to by some companies as “shredders” and “shredders” used for recycling paper, etc. are referred to by others as “grinders” at times.
The subset of reduction processes to which the present invention applies are those where chips/particles are created through a high-speed cutting action using a sharp-edged tooth, as opposed to tearing apart at relatively low speed or inducing fracture through smashing, crushing, and/or impacting with a more blunt implement/tool. However, some of the reduction machines that were originally designed to employ tearing and/or fracture instead of cutting may be outfitted with alternative teeth to result in sharp-edged cutting rather than tearing and fracturing. This is advantageous for many materials, those that are not extremely brittle, in that sharp-edged cutting is more efficient than tearing and blunt-implement fracture by 30% to 60%.
Having differentiated between conventional machining processes and reduction processes that employ a sharp-edged cutting action, prior art in the realm of conventional machining processes is introduced as the foundation of the present innovation. The focus is on the use of round cutting teeth as the present invention explicitly makes use of round cutting teeth, but in a way that is fundamentally different than prior art in both the individual tooth geometry and the way in which the round teeth are oriented relative to the cutting and feeding motions of the process.
In conventional machining processes, a “cutting tooth” is generally defined to have a rake face, a flank face, and a cutting edge defined by the intersection of the rake face and flank face. The rake face is the surface on which the chip is formed and contacts the cutting tooth. The flank face is oriented relative to the cutting motion so as to provide clearance between the cutting tooth and the surface just created by removal of the layer that is converted into chips. In modern conventional machining processes, a cutting tooth is often made up of an indexable “cutting insert” that is affixed to the cutter body so that a worn out cutting edge may be readily and easily replaced with a fresh cutting edge. The term indexable refers to the ability to index the cutting edge to a fresh one, very often to another useable cutting edge on the same cutting insert.
Cutting inserts are generally prismatic having a cross-section of a particular shape, such as but not limited to triangular, square, rhombic, pentagonal, hexagonal, octagonal and circular/round, which is then extruded (not literally, but from the perspective of creating a CAD model where a cross-sectional sketch is drawn and then “extruded” to create the three-dimensional solid) to some thickness of the cutting insert. Using a square cutting insert as an example, the rake face would be the square-shaped surface where each of the four corners would provide a useable cutting edge, allowing the cutting insert to be indexed from one corner to the next until all four corners have been consumed. Some cutting inserts have a clearance face that is not normal to the rake face, that is, the included angle between the rake face and the clearance face at any point on the cutting edge is less than 90°. This provides clearance, relative to the machined surface, that is built into the cutting insert. In this case, the exemplary square cutting insert would have the four useable corners/edges noted. Other cutting inserts have a 90° included angle between the rake face and the clearance face, in which case the cutting insert can generally be flipped over to achieve another four corners (for the exemplary square cutting insert) for a total of eight useable corners. It is noted that a round cutting insert, having a round rake face, has a cylindrical or slightly conical flank surface, thus the use of the term “face” for the flank face may be construed in this instance to be more generally a surface rather than a planar “face”. Furthermore, the corners on polygonal shaped cutting inserts often have a small radius, called the corner radius, that blends the adjacent sides of the polygonal shaped rake face, and in such cases the flank of the tool in the region of the corner radius is not a planar surface as it too is radiused to extend consistently from the corner radiused cutting edge.
It is recognized that many cutting inserts at the current state of the art do not have a planar rake face; rather, they have a rake surface that at a macro scale has a planar reference upon or relative to which bumps, divots, ridges, groves, dishes, and other smaller-scale features are placed and/or superimposed. This can be the case for rake-flank included angles of 90° or less than 90°. These smaller geometric features are generally patterned symmetrically about each corner so that each corner/edge has the same sized, shaped and positioned geometric features as all the other corners/edges. They are often referred to as “chip control” geometry, but their purpose can extend beyond that of controlling chip flow to also permitting more preferential shear conditions for chip formation.
Another class of cutting inserts is generally referred to as “tangential mount”. They too are prismatic having a thickness and a cross-sectional shape. However, it is the surface in the thickness dimension that serves as the rake face and the surface making up the cross-sectional shape that serves as the flank face. These inserts are affixed to the cutter body so that the thickness dimension is presented to the material so that it forms the chip, often being used on rotating cutters (e.g., face mills and cylinder boring tools) and customarily referred to as tangentially-mounted inserts. To achieve favorable shear, chip flow and clearance geometry, tangentially-mounted inserts are generally restricted to triangular, square or rhombic cross-section; that is, not hexagonal, octagonal, round, etc.
In the case of round cutting inserts, the number of useable edges or corners is not defined by their cross-section, as a circle has no corners. That is, a square insert has four corners per side, a triangular insert has three corners per side, a hexagonal insert has six corners per side, and so on. A round insert may be made with faceted or other geometric features on its thickness dimension or on its back side (making it an insert with a single useable side) in a way that promotes easy indexing a pre-set number of times giving a set number of useable edges, or arc segments. Otherwise, it is the responsibility of the tool setter to determine how much the insert should be rotated about its axis to present a new fresh arc segment of cutting edge. However, another unique capability of cutting with round inserts is that the insert may be allowed to rotate while it cuts (U.S. Pat. No. 6,073,524, U.S. Pat. No. 6,135,680, U.S. Ser. No. 12/350,181). With the introduction of the self-propelled rotary tool (SPRT) years ago, a round tooth/insert could now passively rotate as a result of mounting it on a bearing that does not support the rotational degree of freedom. The rotating motion is induced by setting the side rake angle such that the chip flow on the tool rake face induces enough lateral force, call it tangential to the round tooth, so as to rotate the tooth on its bearing; the side rake angle and back rake angle are projections of the rake face into two orthogonal planes as one means of defining the orientation of the rake face relative to the cutting and feeding motions. While the side rake angle is generally set higher than on many other tools, in the range of 10° to 25° (or −10° to β25°), typically, the back rake angle is generally no different than usual cutting teeth, set typically in the range of −5° to +5°. These rotary teeth are then mounted in place of standard fixed teeth on a face mill, at the end of a cylinder boring bar, or on a lathe-turning or facing tool.
Because the round insert in a SPRT is rotating, either continuously or intermittently, while it is cutting material, it is indexing itself to all useable portions of the round cutting edge without human intervention. In addition to reducing the burden of tool change downtime and indexing, every portion of the round cutting edge is used, and equivalently so. Also, when cutting metals, where significantly high temperatures are generated, rotating the tooth spreads the heat source on a continual basis around the entire circumference of the tooth. This allows tools to run faster without unduly compromising tool life, that is, without unduly increasing wear rate, which increases with cutting temperature, which increases with cutting speed. A final advantage of SPRTs is that some of the sliding friction between the chip and the tool is converted into the lower friction (rolling or plain) bearing, hence reducing the frictional component of the cutting power needed, ultimately reducing the specific cutting energy (energy per unit volume removed).
Turning to reduction processes and the cutting elements used in them, “teeth” are often single-edged (e.g., a long/wide wood-chipper/grass/hay-chopper knife) or possibly a two-edged v-shaped protrusion to the drum as is seen in some plastics grinders. Some knives may be flipped around 180° to a second useable edge. Round teeth are not generally used for reduction applications, with the exception of U.S. Pat. No. 5,961,057A and U.S. Pat. No. 6,257,511B1 that make use of a round insert in a way that is similar to one specific embodiment of the present invention.
In reduction processes, it is generally advantageous to use back rake angles of much more positive value, like+30° or greater; this is favorable since it better cuts through the material. This is realizable since many of the materials being reduced (including but not limited to woody and grassy biomass, scrap wood, felt-and-asphalt shingles, gypsum, plastics, cardboard, paper) are of much lower strength, and thus do not need the higher cutting edge strength that comes with back rake angles around −5° to +5° as is required to avoid cutting-edge fracture when cutting higher strength materials (e.g., metals) that are often machined with conventional machining processes. Furthermore, extremely high heat is often not characteristic of reduction processes, given that the materials usually of interest are woody or grassy biomass, construction waste, plastics, cardboard and paper. However, the conversion of friction to (rolling or plain) bearings to achieve more energy efficient cutting is relevant in reduction processes and, at least in the case of woody biomass by the nature of the mechanics associated with forming a wood chip (both slicing through the fibers and the extreme friction due to the wedge indentation that takes place in a way not seen in metal cutting), it is very advantageous showing in lab testing more than 25% reduction in specific energy compared to a stationary knife of equivalent back-rake angle. And, as in conventional machining processes, anything that reduces the need to shut down the equipment for tooth changes is advantageous, even more so in many cases since, unlike in conventional machining processes where a cutting tool may be rather rapidly removed from the machine to index inserts while an alternate tool is installed on the machine allowing it to continue being productive, the drums and discs on reduction machines are very large and not readily removed, resulting in machine down-time equivalent to the time it takes to change all the teeth/knives. The desire to reduce down time for tool changes was also noted in U.S. Pat. No. 5,961,057A and U.S. Pat. No. 6,257,511B1 where the round cutting teeth that are bolted to the chipper disc may be loosened, rotated (i.e., indexed), then retightened. The round tooth and its usage bear similarity to the present invention in a chipper disc embodiment. While the round teeth in U.S. Pat. No. 5,961,057A and U.S. Pat. No. 6,257,511B1 exhibit a positive “reference plane offset” (as defined later as the first of two cutter design variables of the present invention), there is no explicit notation of similar design parameters and as such they differ from the present invention in the following ways:
This invention relates to devices for mechanically removing material from a workpiece or bulk feedstock, creating chips of removed material while producing a new surface on the workpiece or bulk feedstock.
Turning back to the desire to reduce tool-change downtime, embodiments of the present invention allow the round teeth to rotate passively during cutting. There is then no need to loosen a bolt or other fixed clamping/attachment mechanism to manually rotate the round or other shaped cutting insert or knife. The present invention, in its rotating form, does not eliminate tool-change downtime. Because an “equivalent rotary-tooth knife” has approximately (depending on the specific spacing/overlap of adjacent teeth) 4-6 times more cutting edge (the entire circumference of all the adjacent teeth) that is continually active in the process, much more time (4-6 times that of the equivalent standard knife, for example) can elapse between machine shut-downs. In some conventional machining process embodiments, the geometric equivalent number of cutting edges can be as high as 20. And, in prior art SPRT applications, with the additional reduction in wear rate due to spreading heat as noted earlier, for equivalent conditions with a fixed cutting insert, the time between tool changes can be increased by a factor of 30 or more.
a illustrates a three-dimensional view of a single round cutting insert tangentially mounted to a rotating cutter body in the “tangential-mount neutral” state.
b illustrates a side view of a single round cutting insert tangentially mounted to a rotating cutter body in the “tangential-mount neutral” state.
c illustrates a front/end view of a single round cutting insert tangentially mounted to a rotating cutter body in the “tangential-mount neutral” state.
d illustrates a top view of a single round cutting insert tangentially mounted to a rotating cutter body in the “tangential-mount neutral” state.
a illustrates a three-dimensional view of a single round cutting insert tangentially mounted to a rotating cutter body in one of two “conventional-mount neutral” states.
b illustrates a side view of a single round cutting insert tangentially mounted to a rotating cutter body in one of two “conventional-mount neutral” states.
c illustrates a front/end view of a single round cutting insert tangentially mounted to a rotating cutter body in one of two “-conventional-mount neutral” states.
d illustrates a top view of a single round cutting insert tangentially mounted to a rotating cutter body in one of two “-conventional-mount neutral” states.
a illustrates a top view of a single round cutting insert tangentially mounted to a rotating cutter body in one of two “-conventional-mount neutral” states.
b illustrates a front/end view of a single round cutting insert tangentially mounted to a rotating cutter body in one of two “-conventional-mount neutral” states.
c illustrates a side view of a single round cutting insert tangentially mounted to a rotating cutter body in one of two “-conventional-mount neutral” states.
d illustrates a three-dimensional view of a single round cutting insert tangentially mounted to a rotating cutter body in one of two “conventional-mount neutral” states.
a illustrates a three-dimensional view of a single round cutting insert tangentially mounted to a rotating cutter body with the two cutter design variables—reference plane offset and insert axis angle—both greater than zero.
b illustrates a side view of a single round cutting insert tangentially mounted to a rotating cutter body with the two cutter design variables—reference plane offset and insert axis angle—both greater than zero.
c illustrates a front/end view of a single round cutting insert tangentially mounted to a rotating cutter body with the two cutter design variables—reference plane offset and insert axis angle—both greater than zero.
d illustrates a top view of a single round cutting insert tangentially mounted to a rotating cutter body with the two cutter design variables—reference plane offset and insert axis angle—both greater than zero.
a illustrates a side view of a single round cutting insert tangentially mounted to a rotating cutter body with the reference plane offset set to less than zero (insert axis angle is set to zero).
b illustrates a front/end view of a single round cutting insert tangentially mounted to a rotating cutter body with the reference plane offset set to less than zero (insert axis angle is set to zero).
c illustrates a top view of a single round cutting insert tangentially mounted to a rotating cutter body with the reference plane offset set to less than zero (insert axis angle is set to zero).
a illustrates a top view of a single round cutting insert conventionally mounted to a rotating cutter body with the reference plane offset set to less than zero (insert axis angle is set to zero).
b illustrates a front/end view of a single round cutting insert conventionally mounted to a rotating cutter body with the reference plane offset set to less than zero (insert axis angle is set to zero).
c illustrates a side view of a single round cutting insert conventionally mounted to a rotating cutter body with the reference plane offset set to less than zero (insert axis angle is set to zero).
d illustrates a three-dimensional view of a single round cutting insert conventionally mounted to a rotating cutter body with the reference plane offset set to less than zero (insert axis angle is set to zero).
a illustrates a side view of a single round cutting insert conventionally mounted to a rotating cutter body with the reference plane offset set to greater than zero (insert axis angle is set to zero).
b illustrates a front/end view of a single round cutting insert conventionally mounted to a rotating cutter body with the reference plane offset set to greater than zero (insert axis angle is set to zero).
c illustrates a top view of a single round cutting insert conventionally mounted to a rotating cutter body with the reference plane offset set to greater than zero (insert axis angle is set to zero).
a illustrates a side view of a peripheral end mill, slab mill, or chipper drum having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero (but less than 90°).
b illustrates a front/end view of a peripheral end mill, slab mill, or chipper drum having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero (but less than 90°).
c illustrates a three-dimensional view of a peripheral end mill, slab mill, or chipper drum having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero (but less than 90°).
a illustrates a side view of a peripheral end mill, slab mill, or chipper drum having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero (and greater than 90°).
b illustrates a front/end view of a peripheral end mill, slab mill, or chipper drum having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero (and greater than 90°).
a illustrates a side view of a peripheral end mill, slab mill, or chipper drum having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero (less than 90° for one axial region of the cutter and greater than 90° for the other axial region of the cutter).
b illustrates a front/end view of a peripheral end mill, slab mill, or chipper drum having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero (less than 90° for one axial region of the cutter and greater than 90° for the other axial region of the cutter).
c illustrates a three-dimensional view of a peripheral end mill, slab mill, or chipper drum having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero (less than 90° for one axial region of the cutter and greater than 90° for the other axial region of the cutter).
a illustrates a side view (and entering the workpiece) of a right-handed cylinder boring tool having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
b illustrates a front/end view of a right-handed cylinder boring tool having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
a illustrates a front/end view of a left-handed cylinder boring tool having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
b illustrates a side view (and entering the workpiece) of a left-handed cylinder boring tool having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
a illustrates a three-dimensional view (and feeding across the workpiece) of a right-handed face milling tool having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
b illustrates a side view of a right-handed face milling tool having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
c illustrates a front/end view of a right-handed face milling tool having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
d illustrates a top view of a right-handed face milling tool having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
a illustrates a top view of a left-handed face milling tool having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
b illustrates a front/end view of a left-handed face milling tool having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
c illustrates a side view of a left-handed face milling tool having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
d, 16e and 16f illustrate respectively a three-dimensional side and end view of a right-handed face milling tool having multiple tooth sets each having multiple round cutting inserts tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
a illustrates a top view of a right-handed face milling tool having multiple round cutting inserts conventionally mounted to a rotating cutter body and one round wiper tooth insert tangentially mounted with the reference plane offset set to less than zero and the insert axis angle set to slightly less than zero.
b illustrates a front/end view of a right-handed face milling tool having multiple round cutting inserts conventionally mounted to a rotating cutter body and one round wiper tooth insert tangentially mounted with the reference plane offset set to less than zero and the insert axis angle set to slightly less than zero.
c illustrates a side view of a right-handed face milling tool having multiple round cutting inserts conventionally mounted to a rotating cutter body and one round wiper tooth insert tangentially mounted with the reference plane offset set to less than zero and the insert axis angle set to slightly less than zero.
a illustrates a top view of a right-handed face milling tool having multiple round cutting inserts conventionally mounted to a rotating cutter body and one round wiper tooth insert tangentially mounted with the reference plane offset set to greater than zero and the insert axis angle set to slightly greater than zero.
b illustrates a side view of a right-handed face milling tool having multiple round cutting inserts conventionally mounted to a rotating cutter body and one round wiper tooth insert tangentially mounted with the reference plane offset set to greater than zero and the insert axis angle set to slightly greater than zero.
c illustrates a front/end view of a right-handed face milling tool having multiple round cutting inserts conventionally mounted to a rotating cutter body and one round wiper tooth insert tangentially mounted with the reference plane offset set to greater than zero and the insert axis angle set to slightly greater than zero.
a illustrates a top view of a right-handed chipper disc having a single representative round cutting insert tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
b illustrates a side view of a right-handed chipper disc having a single representative round cutting insert tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
c illustrates a front/end view of a right-handed chipper disc having a single representative round cutting insert tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
a illustrates a top view of a right-handed chipper disc having two tooth sets of multiple round cutting inserts each that are tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
b illustrates a side view of a right-handed chipper disc having two tooth sets of multiple round cutting inserts each that are tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
c illustrates a front/end view of a right-handed chipper disc having two tooth sets of multiple round cutting inserts each that are tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angle set to greater than zero.
a illustrates a top view of a right-handed chipper disc having two tooth sets of multiple round cutting inserts each that are tangentially mounted to a rotating cutter body with the reference plane offset set to less than zero and the insert axis angle set to less than zero.
b illustrates a front/end view of a right-handed chipper disc having two tooth sets of multiple round cutting inserts each that are tangentially mounted to a rotating cutter body with the reference plane offset set to less than zero and the insert axis angle set to less than zero.
c illustrates a side view of a right-handed chipper disc having two tooth sets of multiple round cutting inserts each that are tangentially mounted to a rotating cutter body with the reference plane offset set to less than zero and the insert axis angle set to less than zero.
a illustrates a top view of a right-handed abstract extension to a lathe turning tool having a single round cutting insert that is tangentially mounted to a rotating cutter body with the reference plane offset set to less than zero and the insert axis angle set to less than zero.
b illustrates a front/end view of a right-handed abstract extension to a lathe turning tool having a single round cutting insert that is tangentially mounted to a rotating cutter body with the reference plane offset set to less than zero and the insert axis angle set to less than zero.
c illustrates a side view of a right-handed abstract extension to a lathe turning tool having a single round cutting insert that is tangentially mounted to a rotating cutter body with the reference plane offset set to less than zero and the insert axis angle set to less than zero.
a illustrates a side view of a right-handed circular saw having multiple sets of multiple round cutting inserts that are tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angles set to greater than zero.
b illustrates a front/end view of a right-handed circular saw having multiple sets of multiple round cutting inserts that are tangentially mounted to a rotating cutter body with the reference plane offset set to greater than zero and the insert axis angles set to greater than zero.
a illustrates a round cutting insert of the present invention with material removed from the cylindrical rake surface creating a conical rake surface.
b illustrates a round cutting insert of the present invention with material removed from the cylindrical rake surface in the form of a groove on the cylindrical surface adjacent the cutting edge.
a illustrates a round cutting insert of the present invention with material added to one of the two planar surfaces in a way that creates a curved (non-conical) flank surface.
b illustrates a round cutting insert of the present invention with material removed from one of the two planar surfaces creating an inwardly conical flank surface.
a illustrates a round cutting insert of the present invention with material removed from the cylindrical rake surface creating a conical rake surface and with this applied to both axial ends of the insert resulting in two cutting edges.
b illustrates a round cutting insert of the present invention with material removed from the cylindrical rake surface creating a conical rake surface and with this applied to both axial ends of the insert resulting in two cutting edges, the two conical rake surfaces being blended at their intersection, and material added to both planar surfaces to create conical flank surfaces.
a illustrates a round cutting insert of the present invention with material removed from the cylindrical rake surface as a groove adjacent the cutting edge and with this applied to both axial ends of the insert resulting in two cutting edges with a groove adjacent to each.
b illustrates a round cutting insert of the present invention with material removed from the cylindrical rake surface as a groove adjacent the cutting edge and with this applied to both axial ends of the insert resulting in two cutting edges with a groove adjacent to each and material added to both planar surfaces to create conical flank surfaces.
a illustrates a round cutting insert of the present invention with a counter-bore recess on both planar surfaces to receive a mounting element.
b illustrates a round cutting insert of the present invention with a countersink recess on both planar surfaces to receive a mounting element.
a illustrates a round cutting insert of the present invention with one or more small grooves in each of the two flank surfaces and extending from a countersink recess and stopping radially just short of the two cutting edges.
b further illustrates a round cutting insert of the present invention with one or more small grooves in each of the two flank surfaces and extending from a countersink recess and stopping radially just short of the two cutting edges.
a illustrates a mounting element and how it attaches the round cutting insert of the present invention to a cutter body while allowing rotation about the insert axis.
b illustrates a mounting element that attaches the round cutting insert of the present invention to a cutter body while allowing rotation about the insert axis and provides grooves continuous from one end to the other in its outer diameter surface for retention or transmission of grease or cutting fluid.
c illustrates a mounting element that attaches the round cutting insert of the present invention to a cutter body while allowing rotation about the insert axis.
d illustrates a mounting element that attaches the round cutting insert of the present invention to a cutter body while allowing rotation about the insert axis and provides grooves that are not continuous from one end to the other in its outer diameter surface for retention of grease.
e illustrates a mounting element that attaches the round cutting insert of the present invention to a cutter body while allowing rotation about the insert axis and provides grooves continuous from one end to the other in its outer diameter surface for retention or transmission of grease or cutting fluid where the mounting element has an outer sleeve with the grooves and an inner mounting pin.
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
The present invention makes use of one or more round cutting inserts attached to a cutter body. It is best described initially by referring to
Continuing with the most basic initial description of the present invention, the case of a rotating Cutter Body 8 cutting on its periphery is considered as shown in
Referring to
a, 10b and 10c illustrate a peripheral end mill, slab mill, or chipper drum embodiment. The X-Y-Z axes shown correspond to Cutting Insert 1 that is labeled; each cutting insert would have its own X-Y-Z coordinate frame relative to and in which it is located and oriented. Here, Insert Axis Angle 22 has been set to +75° and the cutter Feeding Motion 25 relative to Workpiece 26 is as shown.
If the present invention were applied to a right-handed cylinder boring tool, Insert Axis Angle 22 would likely, without limitation, fall in the range of +30° to +75°.
If the present invention were applied to right-handed face milling tool, Insert Axis Angle 22 would likely, without limitation, fall in the range of +15° to +60°.
Another embodiment of the present invention as applied to a face milling tool is to use a round cutting insert as a wiper. A wiper is used to remove the small cusps that remain on the machined surface from the primary cutting teeth of a face milling tool. U.S. Ser. No. 14/242,680 describes a “round wiper tooth and face mill incorporating the same.” In the context of the present invention and its two cutter design variables—Reference Plane Offset 21 and Insert Axis Angle 22—the wiper tooth described in U.S. Ser. No. 14/242,680 has a negative Reference Plane Offset 21 and a negative Insert Axis Angle 22. Insert Axis Angle 22 would generally be small, say in the range of −2° to −5°, typically.
Turning to an application for reduction of feedstock such as woody biomass, a chipper drum was already noted with similarity to a peripheral end mill or slab mill, embodiments of which were shown in
Returning to a conventional machining process, a lathe turning process may employ the present invention.
Another conventional machining process of interest with the present invention is drilling. Drills are used to create a hole where a hole did not previously exist. Under the present invention, a drill (or drill bit) may be outfitted with tangentially-mounted round cutting inserts to perform the majority of the cutting, but would require a central cutting element that is seen in current products in order to provide cutting in the central region of the hole.
A final process/cutter embodiment of the present invention can provide a circular saw with tangentially-mounted round inserts. This is shown in
Thus far the round cutting inserts have been shown as simple discs for the purpose of illustration. All embodiments would make use of specific round insert geometry features that are part of the present invention. These geometry features of the present invention allow the round cutting inserts, when mounted tangentially, to perform with the greatest strength and utility. Each of the following figures include both a three-dimensional and cross-section view to best illustrate the various embodiments of the tangentially-mounted round Cutting Insert 1.
First, for mounting purposes, Cutting Insert 1 of the present invention would have a Central Hole 51 as shown in
Next, since the tangential mounting of a round cutting insert requires in many embodiments that Reference Plane Offset 21 be positive, the normal rake angle associated with a round cutting insert as shown in
When ample flank clearance is available, the insert may be strengthened by adding material on Planar Surface 3 on the flank side of circular Cutting Edge 7 resulting in Flank Surface 5 being conical. The included angle between Insert Axis 4 and the plane that is tangent to Flank Surface 5 is greater than 90° as shown in
To summarize, a neutral insert of the present invention as shown in
In many cases it is more economical to configure a cutting insert so that it may be flipped over, meaning in this case it has a second circular Cutting Edge 7 where the second Planar Surface 3 intersects Cylindrical Surface 2.
Shown in
Building on
As noted in the background section, some applications may benefit from allowing the tangentially-mounted round Cutting Insert 1 to rotate about its Insert Axis 4. Due to the level of immersion of a Cutting Tooth 1 of the present invention into the material being machined (see
To allow rotation about Insert Axis 4, something is needed other than a threaded fastener or the like that axially clamps Cutting Insert 1 to Cutter Body 8. A threaded fastener may be used, but in such a way that it does not axially clamp Cutting Insert 1, that is, it does not apply significant axial force that results in significant friction that would resist the desired rotational motion about Insert Axis 4.
a shows how Cutting Insert 1 is mounted to Cutter Body 8 with Mounting Element 61. In this case of allowing Cutting Insert 1 to rotate, Mounting Element 61 serves as the “stator” (stationary) or axle and Cutting Insert 1 is the “rotor” (rotating).
The embodiment of Mounting Element 61 in
c shows an embodiment of Mounting Element 61 that has no Passages 64.
As shown in
The final aspect of the present invention is the method of designing tools for tangentially-mounted round cutting inserts.
where Dc is Cut Diameter 14, Di is the diameter of the circular Cutting Edge 7, and Ti is Insert Thickness 52, all three of which are in the same units as Reference Plane Offset 21 in the numerator. In
Chipper Drum/Peripheral End Mill/Slab Mill: 102
Cylinder-Boring Tool: 103
Face Milling Tool/Canting Mill: 104
Chipper Disc (Inward Cutting): 105
Chipper Disc (Outward Cutting): 106
Face Milling Tool/Canting Mill Wiper (Inward Cutting): 107
Face Milling Tool/Canting Mill Wiper (Outward Cutting): 108
Lathe Turning Tool: 109
Lathe Facing Tool: 110
Those of conventional mounting of inserts include, for relative comparison:
Conventional Cylinder-Boring Tool: 111
Face Milling Tool: 112
Frusto-conical Insert Face Milling Tool (using insert of U.S. Pat. No. 4,621,195): 113
The present invention includes the general method that is used to design any cutting tool using tangentially-mounted round cutting inserts. The steps and their relationships are shown in
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.
This application is a continuation in part of U.S. Ser. No. 14/242,680 filed Apr. 1, 2014 which claims the benefit of U.S. provisional application Ser. Nos. 61/807,285 and 61/807,225 both filed Apr. 1, 2013, the disclosures of which are hereby incorporated in their entirety by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 61807285 | Apr 2013 | US | |
| 61807225 | Apr 2013 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14242680 | Apr 2014 | US |
| Child | 14502035 | US |
