US20100210186A1

US20100210186A1 - Multi-head fluid jet cutting system

Info

Publication number: US20100210186A1
Application number: US12/388,355
Authority: US
Inventors: Brian R. Panuska; Joseph C. Hammer; Stewart Cramer
Original assignee: LAI International Inc
Current assignee: LAI International Inc
Priority date: 2009-02-18
Filing date: 2009-02-18
Publication date: 2010-08-19

Abstract

Embodiments of the invention provide multi-head fluid jet cutting systems and methods of utilizing such devices. A multi-head fluid jet cutting system includes a body having a plurality of fluid jet cutting heads installed therein. Each cutting head receives pressurized fluid from an intensifier and directs the fluid along a jet axis out of a nozzle of the head to form a cutting stream. In some embodiments, an abrasive material can be mixed with the fluid to form an abrasive fluid cutting stream. The body can be mounted to a motion system which moves the body, and therefore the cutting heads, relative to a work piece mounted upon a work bed. Each of the fluid jet cutting heads is coupled to an actuator which can control an on/off state of the cutting head. In some embodiments, an actuator mounting plate is provided to enable mounting of the actuators off of the jet axes.

Description

TECHNICAL FIELD

The present specification relates to a fluid jet cutting system. In particular, a multi-headed fluid jet cutting system and methods utilizing the same are disclosed.

BACKGROUND

Fluid jet cutting systems utilize high velocity fluid (e.g. water) to cut materials. One type of fluid jet cutting system is an abrasive fluid jet (“AFJ”) cutting system. In AFJ cutting systems, particles of an abrasive material (e.g. garnet) can be introduced into the high velocity fluid jet to provide increased cutting capability. Fluid jet cutting systems can provide clean, burr-free cuts in a wide variety of materials including leather, meat, plastics, metal (e.g. steel), and glass.
Fluid jet cutting systems can be utilized to generate cuts of a wide variety of shapes. In order to make these cuts, many fluid jet cutting systems are connected to a motion system. Motion systems can provide varying levels of control of the cutting heads, from very precise computer controlled motions, to handheld systems incorporating physical templates. In each case, motion systems are often large and expensive, rendering motion system up-time a critical factor in the economics of utilizing such cutting systems.
Many fabrication processes require the cutting of a plurality of identical, uniformly spaced features within or from a work piece. Examples of work pieces having such features include grates, gears, or screens. Fluid jet cutting systems can be utilized to create such features. In such operation, the issue of motion system up-time can be addressed by coupling multiple fluid jet cutting heads to a single motion system. However, the physical size of fluid jet cutting heads and actuators (which are used to selectively activate cutting heads) can prevent the ideal separation distance between cutting heads from being realized.
Fluid jet head spacing issues become a problem at certain feature size and spacing. For small, or closely spaced features, physical limitations of fluid jet cutting heads can make it impossible to pack cutting heads close enough to cut adjacent features. In this case, features must be interleaved or separately created, however, such operation can result in inefficiencies with regard to motion system utilization.

SUMMARY

In a first aspect, the invention features a fluid jet cutting system. The fluid jet cutting system includes a work bed which can receive and fixedly position a work piece. A plurality of fluid jet cutting heads, each adapted to deliver a cutting stream toward the work piece, are installed are installed within a body which is mounted to a motion system. The motion system is configured to move the body relative to the work piece. Actuators in fluid communication with the fluid jet cutting heads, are configured to control delivery of pressurized fluid from an intensifier to each of the cutting heads. An abrasive material source can be provided to deliver abrasive material to each fluid jet cutting head. The system is controlled by a controller which can control the motion of the body relative to the work piece as well as the selective activation of each of the fluid jet cutting heads such that a predetermined pattern can be cut from the work piece.
According to another aspect of the invention, a fluid jet cutting head mount is disclosed.
The fluid jet cutting head mount includes a plurality of individually activated fluid jet cutting heads in a body. Each of the fluid jet cutting heads include a fluid inlet orifice and nozzle. Some fluid jet cutting heads further include a mixing chamber and an abrasive feed inlet. The mixing chamber can be in fluid communication with the fluid inlet and abrasive feed inlet such that abrasive material entering the chamber via the abrasive feed inlet is mixed with fluid from the fluid inlet. The mixed fluid and abrasive material can pass from the mixing chamber out the nozzle to form a cutting stream. In some embodiments, the fluid jet cutting head mount further includes a wear plate mounted to an exposed surface of the body.
According to another aspect of the invention, a method for cutting identical features within a work piece is disclosed. The method includes the step of providing a fluid jet cutting system having a plurality of close-packed fluid jet cutting heads coupled with a motion system. A work piece can be installed within the fluid jet cutting system. And the system can be activated, thereby simultaneously cutting two or more features within the work piece.
Embodiments of systems and methods according to the present invention can provide for the simultaneous cutting or treatment of identical features within a work piece. Moreover, some embodiments allow for efficient motion system utilization while such cutting or treatment is performed. In addition, some embodiments can reduce required interleaving in cutting features having small feature size or spacing. Moreover, such features are accomplished while allowing access to portions of the abrasive fluid jet cutting system that are subject to wear (e.g. the fluid inlet orifice and nozzle), for system maintenance.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings are illustrative of particular embodiments of the invention and therefore do not limit the scope of the invention. The drawings are not to scale (unless so stated) and are intended for use in conjunction with the explanations in the following detailed description. Embodiments of the invention will hereinafter be described in conjunction with the appended drawings, wherein like numerals denote like elements.

FIG. 1 is a perspective view of a fluid jet cutting system according to some embodiments.

FIG. 2 is a side cross-sectional view of a body having multiple AFJ cutting heads installed therein, according to some embodiments.

FIG. 3 is a perspective view of a body according to some embodiments.

FIG. 4 is a perspective view of actuators mounted to an actuator mount and connected to a body according to some embodiments.

FIGS. 5A and 5B are top plan views of articles each having a plurality of patterned features.

FIG. 6 is a side cross-sectional view of a body having multiple fluid jet cutting heads installed therein, according to some embodiments.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The following detailed description is exemplary in nature and is not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the following description provides practical illustrations for implementing exemplary embodiments of the present invention. Examples of constructions, materials, dimensions, and manufacturing processes are provided for selected elements, and all other elements employ that which is known to those of skill in the field of the invention. Those skilled in the art will recognize that many of the examples provided have suitable alternatives that can be utilized.
The term “fluid jet” refers to a high velocity fluid stream used for cutting or cleaning purposes. One common type of fluid jet is a water jet, where the fluid used as the jet stream is water. The term “abrasive fluid jet” (“AFJ”) refers to a fluid jet having particles of an abrasive material mixed in with the jet. An abrasive water jet is an abrasive fluid jet wherein the fluid stream in which the abrasive material is mixed comprises water. A variety of abrasive materials can be mixed with fluid in an abrasive water jet, including, for example, garnet, silicon carbide, aluminum oxide, boron nitride, etc. As used herein, unless otherwise noted, the term “fluid jet” should be construed to include both “fluid jets” and “abrasive fluid jets.” In addition, the term “cut” or variants thereof, as used herein, should be read to include other physical processes such as abrading, carving, reaming, stripping, and shaping a work piece or a surface thereof.
FIG. 1 shows a perspective view of a fluid jet cutting system 100 according to some embodiments. The fluid jet cutting system 100 can be used to cut a work piece 125 mounted upon a work bed 130. To do so, a motion system 145 coupled about the work bed 130 can be used to move a body 105 having a plurality of fluid jet cutting heads 110 installed therein relative to the work piece 125. During this movement, actuators 140 mounted to the motion system can selectively permit or deny a flow of pressurized fluid from an intensifier 115 to one or more of the fluid jet cutting heads 110. In some embodiments, an abrasive material source 135 can supply an abrasive material to one or more of the fluid jet cutting heads 110 to allow for abrasive fluid jet cutting. The motion of the motion system 145 and control of the actuators 140 and, in some embodiments, abrasive feed, can be coordinated by a controller 150 which can be manually controlled or pre-programmed to cut a predetermined pattern within the work piece 125.
The fluid jet cutting system 100 comprises a body 105 having a plurality of fluid jet cutting heads 110 installed therein. Each fluid jet cutting head 110 is configured to convert high pressure fluid received from an intensifier 115 into a high velocity fluid flow. The high velocity fluid flow or jet can be ejected from the fluid jet cutting head 110 as a cutting stream 120 which can be used to cut the work piece 125. In some embodiments, the cutting streams 120 comprise abrasive cutting streams wherein an abrasive material delivered to the fluid jet cutting head 110 from an abrasive material source 135 is introduced into the fluid flow. Actuators 140 coupled in fluid communication between the intensifier 115 and each fluid jet cutting head 110 can be used to selectively activate one or more of the heads.
FIG. 2 shows a side cross-sectional view of a multi-head body 200, according to some embodiments, which can be utilized in fluid jet cutting systems such as that of FIG. 1. The multi-head body 200 generally comprises a block 205 having multiple fluid jet cutting heads 210, 210′ installed about jet axes 215, 215′ which pass through the block 205. While the cross section of FIG. 2 shows but two fluid jet cutting heads 210, 210′ it should be understood, and will become apparent, that additional fluid jet cutting heads can be installed within the body 205 about jet axes not visible in the current view, e.g. behind the shown cutting heads 210, 210′.
Because embodiments provide for the mounting of a plurality of fluid jet cutting heads within a single block, head packing efficiency can be increased. In particular, a plurality of fluid jet cutting heads can be positioned with respect to one another such that the distance between two or more of the jet axes are closer than can be achieved with heads having separate bodies. Such systems will be referred to herein as “close-packed” fluid jet cutting heads. As described below, close-packed fluid jet cutting heads can provide for efficient usage of motion system resources, and thus decrease the cost per article associated with fluid jet treated articles.
Each fluid jet cutting head 210 comprises a main bore 220 which provides a fluid flow path, axially aligned with a jet axis 215, through the block 205. Component parts of the head operate to accelerate pressurized fluid entering the main bore at a fluid inlet 225 and exiting via a nozzle 230 to form the cutting stream. In some embodiments, a mixing chamber 235 interposed between the fluid inlet 225 and nozzle 230, can allow for the introduction of an abrasive material into the fluid flow and thus, the cutting stream.
The fluid inlet 225 of the fluid jet cutting head 210 shown in FIG. 2 comprises an inlet cap 226, fluid inlet orifice 227, and orifice-alignment 228. The inlet cap 226 is adapted to receive a connector 240 of a fluid inlet tube which delivers pressurized fluid to the head 210 from an intensifier. In some embodiments, the inlet cap 226 receives the fluid inlet connector 240 such that the fluid inlet tube is axially aligned about the jet axis 215. A forward end of the inlet cap 226 or fluid inlet connector 240 provides a sealing force against a seat assembly 229 which retains fluid inlet orifice 227 in axial alignment with the jet axis 215. In some embodiments, one or more weep holes 245 can be drilled or otherwise formed about the fluid inlet 225 to allow for weeping of excess fluid. The fluid inlet orifice 227 generally comprises a hard material (e.g. diamond, sapphire, or ruby) having an opening on the order of 0.003 inches-0.020 inches. During use, the fluid inlet orifice 227 may require frequent replacement as it erodes under the high pressure of fluid passing through the opening. As such, some embodiments provide ready access to the fluid inlet orifice 227. For example, in the embodiment shown, the inlet cap 226 is connected to the block 205 by a threaded connection allowing for the cap to be unscrewed and removed for access to the fluid inlet orifice 227. Some embodiments further include an orifice-alignment 228, such as the cone-shaped path shown connecting the fluid inlet orifice 227 and mixing chamber 235.
Progressing along the fluid flow path, in this embodiment, the fluid inlet 225 is in fluid communication with mixing chamber 235. The mixing chamber 235 can comprise a cavity within an insert 236 installed in a transverse bore 237 that intersects the main bore 220 of the cutting head 210. An abrasive feed inlet 239 threadably engaged with the block 205 can apply a retention force against the insert 236 to lock the insert 236 within the transverse bore 237. The abrasive feed inlet 239 is connected with an abrasive material source which can deliver abrasive material to the mixing chamber 235. Abrasive material generally comprises an approximately normal distribution of particles of a hard material, such as, for example garnet or milder or more aggressive abrasives. During use, abrasive material delivered to the mixing chamber 235 mixes with the fluid and is driven out of the mixing chamber 235 along the fluid flow path.
Mixed fluid and abrasive material (or just fluid, in some embodiments) exiting the mixing chamber 235 enter a nozzle 230, which is fluidly connected thereto. Within the nozzle 230 the fluid and abrasive material are directed into an outlet channel 231, for example via an inverted conical section, which is axially aligned with the fluid flow channel. The fluid and abrasive material flow through the outlet channel 231 and are ejected out of the nozzle end 232 to form the cutting stream. The nozzle 230 can comprise a tubular section having an outlet channel 231 with a diameter that is larger than the diameter of the fluid inlet orifice to accommodate flow of the abrasive material. Often the size of the outlet channel can be expressed as a ratio compared with the orifice diameter. Such ratios can be, for example, approximately 3:1.
In some embodiments, nozzle 230 is a replaceable nozzle, which is retained within the body 200 by a shaft collar 250. Due to wear, nozzles generally must be replaced relatively rapidly (e.g. after 24-36 hours of use in some cases). Embodiments which include a collar 250, can facilitate simple and rapid swapping out of nozzles. Moreover, in some embodiments, the use of a collar allows for fine adjustment of the nozzle 230 relative to the fluid flow channel. In such embodiments, a nozzle 230 can be slightly angled or shifted side to side so that the outlet channel 231 aligns directly with the jet axis 215 providing extended nozzle life and improved cutting head operation. Some embodiments may further include a seal element 252 which may be positioned about the nozzle 230 at the collar junction.
In some embodiments, fluid jet cutting heads can be depthwise offset within the block 205. For example, in the embodiment of FIG. 2, one of the cutting heads 210 is offset from the other 210′ by a depth of D_offset. As a result, one of the nozzles 230′ protrudes further from the exposed surface of the body 260 than the other nozzle 230. Such an arrangement may be utilized to maintain constant nozzle standoff where the cutting heads are used to cut through or otherwise treat a work piece at an oblique angle relative to, i.e. neither perpendicular nor parallel to, the work piece surface (e.g. 25 degrees). The depth of offset can depend upon several factors including the desired standoff for each nozzle, the cutting stream separation, and the cutting stream angle.
FIG. 6 shows a side cross-sectional view of another embodiment of a multi-head body 600. In this embodiment, the body 600 comprises a block 605 having a plurality of pure (i.e. non-abrasive) fluid jet cutting heads 610, 610′ installed about jet axes 615, 615′. A main bore 620 axially aligned about the jet axis 615 provides a fluid path from a fluid inlet 625 to a nozzle 630. As with the abrasive fluid jet cutting head, the fluid inlet 625 includes an inlet cap 626 and a fluid inlet orifice 627. The inlet cap 626 is adapted to receive a connector 640 of a fluid inlet tube which delivers pressurized fluid to the head 610 from an intensifier. The fluid inlet orifice 627 includes an opening through which the pressurized fluid is directed, forming a high speed fluid flow. This high speed fluid flow can be directed out of the body via an outlet channel 631 of nozzle 630 to form the (fluid only) cutting stream.
While the embodiments disclosed herein have only be described with reference to two specific models of fluid jet cutting heads, it should be understood that numerous fluid jet cutting heads are known in the art, many of which are readily adaptable by one of ordinary skill in the art for use with embodiments of the present invention. In addition, pure fluid jet operation can be achieved from AFJ cutting heads by capping, or otherwise closing the abrasive feed inlet such that no abrasive material is provided to mix with the fluid flow. Thus, the above discussion should not be limited to the particular embodiments of fluid jet cutting heads disclosed.
Referring back to FIG. 2, the body 200, comprises a block 205 to receive each of the fluid jet cutting heads 210, 210′. The block 205 comprises a metal or other rigid material of suitable strength to retain the fluid jet cutting heads 210, 210′. In some embodiments, the block comprises stainless steel, e.g. Grade 316 stainless steel. The block 205 should be capable of sustaining internal pressures of 20,000 p.s.i. to 90,000 p.s.i. or greater as the block 205 must be capable of withstanding the high pressure fluid directed within each fluid jet cutting head 210
Some embodiments can include additional features, such as for example a wear plate 255. At typical cutting head standoff (e.g. ⅛″ between the nozzle end and work piece surface), the exposed surface of the body 260 can experience splash back of fluid and/or abrasive. Over time, this splash back can erode the body 200 at the exposed surface 260. Thus, the body 200 can include a wear plate 255 which can be removably mounted to the exposed surface 260. The wear plate 255 can be mounted to the body 200, for example, by one or more magnets 265 located adjacent the exposed surface 260. Once a wear plate has been worn to a particular degree, it can be removed and replaced with a new plate. Such a feature can increase the lifespan of bodies according to some embodiments.
Moreover, the body 200 should include a mounting mechanism so that it can be connected to the motion system. In some embodiments, the mounting mechanism comprises one or more threaded or through bores within the block 205 such that a bolt or other threaded fastener may be passed through the motion system carriage and received by the body 200.
FIG. 3 shows a perspective view of a body 300 including multiple fluid jet cutting heads 305 according to some embodiments. The body 300 shown herein is generally analogous to that of FIG. 2, with all heads 305 mounted within the body 300 now visible. In this embodiment, the body 300 includes four fluid jet cutting heads 305 aligned in two offset rows 310, 312. Although the invention is not limited to a two-by-two array of cutting heads, some embodiments include such an arrangement because it balances cutting head multiplicity while maintaining access to each head (e.g. for maintenance purposes). In addition, embodiments should not be limited to those providing offset rows. Indeed, a simple rotation of the body 300 of FIG. 3, reveals that by this arrangement, non-offset rows can be attained (resulting in rows 310′, 312′).
The delivery of pressurized fluid to each of the fluid jet cutting heads can be controlled by actuators. Referring back to FIG. 1, actuators 140 are shown coupled in fluid communication between the fluid jet cutting heads 110 and the intensifier 115. Unlike many previously known fluid jet cutting systems, the actuators 140 are coupled off-axis of the jet axis. That is, rather than being coupled directly to the fluid inlet of each of the fluid jet cutting heads 110, the actuators 140 fluidly connect with the cutting heads via a length of tubing 155. The actuators 140 can then be mounted to a mounting plate 160, which is coupled with the motion system 145, e.g. to carriage 146. Providing for mounting of the actuators off-axis of the jet axes can allow for closer packing of the fluid jet cutting heads because the actuators generally have a larger diameter than the cutting heads themselves. Of course, where actuators are used which have a diameter equal to or narrower than the diameter of the cutting heads, off-axis mounting may not be necessary to achieve close-packing.
FIG. 4 shows a perspective view of actuators 410 mounted to a mounting plate 430 and fluidly connected with a body 405 according to some embodiments. The actuators 410 comprise an actuator housing 411 disposed about an actuator axis 412, a fluid inlet 413, and a fluid outlet 414. High pressure fluid from the intensifier enters the actuator via the fluid inlet 413. A length of tubing 420 connects the actuator fluid outlet 414 to a fluid inlet of an associated fluid jet cutting head within the body 405. The tubing 420 can comprise a high pressure, thick-walled tube or whip. A valve, e.g. a pneumatic valve, within the actuator housing 411 selectively permits or denies passage of the high pressure fluid to the fluid outlet 414 based upon a signal received at a control input 415. Thus, each actuator 410 can be used to control an on/off state of the associated fluid jet cutting head.
Actuators can further include an actuator mount 425 about a portion of the actuator housing 411 so that the actuator can be fixedly coupled to the mounting plate 430. In some embodiments, the actuators are mounted such that the actuator axes 412 are not axially aligned about jet axes 407. For example, as shown in FIG. 4, the actuator axes 412 are located within a plane that is generally perpendicular relative to their respective jet axes 407. This can allow for close-packing of the cutting heads. One of ordinary skill will recognize that many different mounting arrangements will provide for mounting of the actuators to allow for close packing of the associated fluid jet cutting heads, each of which should be considered within the scope of the invention.
Referring back to FIG. 1, the body 105 and actuators 140 can be mounted to a motion system 145 which provides positional control of the fluid jet cutting heads 110. In some embodiments, the motion system is adapted to move the body 105 relative to the work piece 125. Motion systems suitable for use with fluid jet cutting systems should be sized based upon the dimensions of the work piece upon which the system will be working. This size can vary greatly, for example, some systems can be 2 feet×4 feet, while others can be 30 feet×100 feet.
Embodiments of the invention can utilize generally any motion system commonly associated with fluid jet cutting systems. For example, the system 100 shown in FIG. 1 comprises a motion system 145 adapted for cutting a two-dimensional work piece. This motion system 145 allows for cutting of a work piece along two axes X, Y, and raising/lowering of the body 105 along a third axis Z to account for cutting head standoff. Here, the body 105 and other fluid jet cutting system components are coupled with a carriage 146 which is slidably mounted to a cross beam 147. The cross beam 147 is slidably coupled at each end to side beams 148. Motion along the y-axis Y can be accomplished by moving the cross beam 147 along the side beams 148. Motion along the x-axis X can be accomplished by moving the carriage 146 along the cross beam 147. And motion along the z-axis Z, corresponding to adjustments of the head height or standoff, can be accomplished by raising or lowering one or both of: (i) the carriage 146, or (ii) the body 105 and/or heads 110 on the carriage 146.
Systems of the type shown in FIG. 1 are commonly referred to as “gantry systems.” In a gantry system, translational motion along three axes (x-axis X, y-axis Y, and z-axis Z) can be facilitated, as described above. Additional axes of motion can be included in some embodiments, for example, a rotor connection between the carriage 146 and body 105 can provide for rotation about the y-axis Y. In all cases, motion can be accomplished by manual crank, motorized screw, or fully programmable servomechanisms. In most cases, servo-motors are utilized to allow for precise computer control.
In addition to gantry systems, embodiments of the invention can be adapted for use with other motion systems known in the art. Such systems can include other two-dimension (XY, or flat stock) motion systems, such as a cantilever system. Two-dimensional motion systems can be used for cutting flat patterns from sheet material such as plastic, rubber, foam, metals, composites, glass, stone, and ceramics. Alternatively, three dimensional (five-axis) cutting systems can be utilized. These systems can include manual motion systems, such as a handheld, counterweighted fluid jet gun utilized in conjunction with a cutting template, or, fully programmable, five-axis motion systems.
It should also be noted that, in light of the above discussion, multiple bodies can be incorporated into a single motion system. The only realistic limit to either the number of cutting heads per body or bodies mounted to the motion system are essentially logistical in nature. Factors to consider, which are usually ones of scale, include: access space for components (e.g. nozzles, orifii, and remote actuators), the required spacing of the cutting heads, sufficient fluid supply (e.g. space for additional intensifiers and whip space and bending loads), sufficient abrasive, programming for individual cutting head states, and electrical control lines for actuator (pneumatic) control.
Referring back to FIG. 1, in many embodiments, the motion system 145 is mounted about a work bed 130 adapted to receive and fixedly position the work piece 125. The work bed 130 can comprise a surface upon which the work piece 125 is mounted. Although much of the momentum of the fluid jet cutting streams 120 is absorbed by the work piece 125 during operation, the cutting streams 120 can retain significant cutting force when exiting a work piece. Thus, a work bed 130, according to some embodiments, can include a fluid filled catch tank 132 to disperse the fluid jet energy after it cuts the part. In addition, the work bed 130 can incorporate grating or slats to support the work piece 125. In some implementations, these supports can be slowly consumed during the cutting process, and can require regular replacement. In some embodiments, the catch tank may further comprise a re-feeder. A re-feeder can allow for the manual or automatic collection of used abrasive material and/or fluid. Once collected, the used abrasive material be filtered, sifted, and delivered back to the abrasive material source 135 for reuse. Likewise, the fluid can be filtered and recycled in some embodiments.
Multi-head fluid jet cutting systems 100, according to some embodiments, further include one or more intensifiers 115. The intensifier 115 can comprise any of a variety of high pressure fluid sources known in the art. Generally intensifiers for use with systems according to embodiments of the invention comprise a source of pressurized fluid ranging from 20,000 p.s.i. to 90,000 p.s.i. or greater. Many such intensifiers are commercially available, e.g. the “iP55-200 Intensifier Pump” available from Jet Edge of St. Michael, Minn. Other high pressure pumps may include direct drive, gear or crankshaft pumps that may be electrically or internal combustion engine driven.
Embodiments comprising a fluid jet cutting system 100 can further include an abrasive material source 135. The abrasive material source 135 can comprise a bulk hopper 135 capable of holding the abrasive material. A pressurized line from the bulk hopper 135 can feed abrasive material to mini-hoppers 137, coupled with the carriage 146. Each mini-hopper 137 receives abrasive material from the bulk hopper 135 and feeds an associated fluid jet cutting head 110.
Multi-head fluid jet cutting systems 100 can further comprise a controller 150. The controller 150 can be connected with the motion system 145 and actuators 140 to provide precision control of system operation. The controller can comprise any device capable of controlling the motion of the body 105 as well as the activation of the cutting heads 110 such as a servomechanical computer numerical control (“CNC”) system or computer software interface. In some embodiments, separate controllers may be provided for each function. Where a CNC system is utilized in conjunction with a four-head system (such as that of FIG. 3), programming each of the possible on/off states can require sixteen different command codes to encompass the full suite of active nozzle on/off combinations. An increased number of cutting heads would multiply these command codes geometrically.
Embodiments such as those described above can be utilized in conjunction with methods for creating a plurality of identical features within a work piece. Such methods can include providing a multi-head, close-packed fluid jet cutting system, such as those described above. A work piece can be installed within the fluid jet cutting system, for example, upon a work bed. The system can then be activated. Activation of the system can include directing the motion system to move the body relative to the work piece, tracing out the desired features while two or more of the fluid jet cutting heads are simultaneously activated. The step of activating the system can be accomplished by causing a controller to implement a predetermined pattern, such as a plurality of offset slots. Some methods, allow for the simultaneous creation of adjacent features.
FIGS. 5A and 5B will be discussed to illustrate uses and advantages of systems according to some embodiments. FIG. 5A shows an article 500 comprising a plurality of identical features 510 cut within a sheet 505. The features 510 are cut within offset rows 530, 540. FIG. 5B shows an article 550 comprising a sheet 555 having a plurality of features 560, 570 cut therewithin. Features of a first type 560 are aligned within a first row 580, and features of a second type 570 are aligned within a second row 590.
A fluid jet cutting system including a single cutting head, can be utilized to create the articles 500, 550 of FIGS. 5A and 5B. To do so, the sheet 505, 555 can be installed within the fluid jet cutting system (i.e. as the work piece), and the cutting head can be moved along a path tracing one of the features 510, 560, 570 while the cutting stream is activated. The fluid jet cutting stream can then be deactivated so that the head can move to a starting point of another of the features 510, 560, 570. At this location, the cutting stream can again be activated and the tracing path repeated. This process can be repeated for each of the features 510, 560, 570 of the articles 500, 550. Such a system would require, for example, eight tracings to create the features 531-538 of row 530 of article 500. Accordingly, single-headed fluid jet cutting systems may be capable of creating multiple features, albeit one-at-a-time, within a work piece.
To more efficiently create repeating identical features within a work piece, multiple cutting heads can be used. For example, with reference to the article 500 of FIG. 5A, where two cutting heads linearly separated by a distance of, for example D₃, are separately attached to a single motion system, two features can be cut simultaneously. In such a system, a first of the cutting heads may be positioned to cut feature 531 which would result in the second cutting head being positioned to cut feature 534. Thus, with a single tracing of the feature path by the motion system and simultaneous activation of both cutting heads, two features 531, 534 can be cut. Accordingly, the time required to complete the article, i.e. cut every feature in the work piece, can be significantly reduced.
Article cost is a function of machine up-time and efficiency. Each tracing made by the motion system increases the amount of time required to make the article, and therefore the article cost. In addition, traverse times between feature tracings increase part cost. Thus, it is desirable to minimize the number of tracings and the traverse times required to fabricate a particular article. The following paragraphs illustrate three exemplary fluid jet cutting setups with regard to the fabrication time required for the article 500 shown in FIG. 5A.
With reference to row 530, to cut each feature 531-538 using a cutting system including two cutting heads spaced a distance D₁apart, the feature path must be traced four times with both cutting heads operating during each tracing. That is, during the first tracing, features 531 and 532 are cut. During the second tracing, features 533 and 534 are cut. During the third tracing, features 535 and 536 are cut. And during the fourth tracing, features 537 and 538 are cut. Such a cutting pattern can be referred to as an “adjacent pattern” because during each tracing, adjacent features can be cut.
Using a cutting system that includes two cutting heads spaced a distance of D₂apart, four tracings are likewise necessary. In this case, during the first tracing, features 531 and 533 are cut. During the second tracing, features 532 and 534 are cut. During the third tracing, features 535 and 537 are cut. And during the fourth tracing, features 536 and 538 are cut. Such a cutting pattern can be referred to as an “interleaved pattern” because during each tracing, non-adjacent slots are cut leaving a feature gap. The features within the feature gap must then be cut with an interleaved trace. In this case, the interleaved pattern is a single-gapped interleaved pattern, the feature gap comprising one feature.
Multiple-gapped interleaved patterns can increase the number of required tracings leading to sub-optimal performance. An example of a multiple-gapped interleaved pattern is apparent for a cutting head separation distance of D₃. At this separation distance, during the first tracing, features 531 and 534 can be cut, leaving a two feature gap. During a second tracing, interleaved feature 532 and feature 535 can be cut. And during a third tracing, interleaved feature 533 and feature 536 can be cut. At this point, features 537 and 538 remain to be cut. Because these remaining features are separated by a distance less than the head separation distance D₃, two tracings (with only one head activated during each cut) are needed. Thus, at this separation distance, five tracings are required to cut the eight features 531-538, rather than the four tracings required at shorter head separation distances. As the head separation distance increases (or feature size/spacing decreases), more tracings where only one of the heads can be activated are required producing inefficiencies in fluid jet cutting head usage.
With any multi-headed fluid jet cutting system, there are physical limitations on the minimum separation distance achievable between the cutting heads. These physical limitations generally include the physical components of each cutting head, e.g. the cutting head body, connectors, nozzle, and actuators. Close-packed systems, such as those described herein, can include a single body in which the heads can be mounted, thus eliminating the need for multiple bodies and other cutting head parts. Thus, close-packed systems can provide for cutting head separation distances that are smaller than those which can be achieved with separately-mounted cutting heads.
Accordingly, close-packed fluid jet cutting heads are more likely to provide for adjacent pattern operation, or at least, reduced interleave gap sizes. FIG. 5B is illustrative of this concept. Assume, for example, that D₂is the minimum separation distance achievable utilizing separately-mounted fluid jet cutting heads, and D₁is the separation distance achievable utilizing close-packed cutting heads, e.g. according to embodiments of the invention. As is apparent from row 580, at separation distance D₁, features 581, 582 can be simultaneously traced resulting in adjacent pattern operation. At separation distance D₂, features 581, 583 can be simultaneously traced resulting in single-gapped interleaved pattern operation.
However, the article 550 of FIG. 5B further comprises features of a second type 570 as shown in row 590. These features 570 are smaller than the features of the first type 560. When it comes to cutting the features of the second type 570, the system having minimum separation distance D₁, can achieve single-gapped interleaved pattern operation, i.e. simultaneously cutting features 591, 593 and leaving one interleaved feature 592. Meanwhile, the system having minimum separation distance D₂, can achieve only three-gapped interleaved pattern operation, i.e. simultaneously cutting features 591, 595 and leaving three interleaved features 592, 593, 594. As described above, although not as desirable as adjacent pattern operation, the single-gapped interleaved pattern operation achievable by the close-packed system can result in more efficient operation than the three-gapped interleaved pattern operation achievable by the separately mounted cutting heads. Thus, while adjacent pattern operation in one application (e.g. cutting row 580) does not necessarily result in adjacent pattern operation in every other application (e.g. cutting row 590), close-packing of fluid jet cutting heads can allow for reduced interleaved gap sizes.
The above described example, illustrates the efficiencies that can be gained from close-packing two fluid jet cutting heads. By reducing the head separation distance, i.e. such that adjacent pattern operation or reduced interleaved gap sizes can be achieved, the required number of tracings can be reduced. In addition, fluid jet cutting head utilization, i.e. the amount of time during which multiple (ideally all) cutting heads are activated, can be increased. Thus, embodiments including close-packed fluid jet cutting heads can increase fabrication efficiency and thereby reduce article cost.
The desire to close-pack fluid jet cutting heads can also apply to systems using more than two cutting heads. For example, with reference to FIG. 5A, a system utilizing three fluid jet cutting heads having a separation distance D₁(i.e. the first head positioned to cut feature 531, the second head positioned to cut feature 532, and the third head positioned to cut feature 533) can cut each of the features 531-538 of row 530 in three tracings. In the first tracing, features 531, 532, 533 can be cut. In the second tracing, features 534, 535, 536 can be cut. And in the third tracing, with only two of the three cutting heads activated, features 537, 538 can be cut.
In comparison, a system including three fluid jet cutting heads having a separation distance of D₂(i.e. the first head positioned to cut feature 531, the second head positioned to cut feature 533, and the third head positioned to cut feature 535) requires four tracings to cut each of the features 531-538 of row 530. In the first tracing, features 531, 533, 535 can be cut. In the second tracing, features 532, 534, 536 can be cut. At this point, features 537 and 538 remain to be cut. Because these remaining features are separated by a distance less than the head separation distance D₂, two tracings (with only one head activated during each cut) are needed, for a total of four tracings.
As should be apparent to one of ordinary skill in the art, the efficiencies described above can be extended by some embodiments of the present invention. For example, motion system utilization can be extended by providing close-packed rows of close-packed fluid jet cutting heads. For example, the embodiment of FIG. 3, including two rows of two close-packed fluid jet cutting heads can be utilized to simultaneously cut features 531, 532, 541, 542 in the article 500 of FIG. 5A. Of course, embodiments are not limited to the two-by-two arrangement shown, as larger and more varied arrangements can be utilized. At an extreme, an embodiment can include one cutting head for each feature to be cut within the work piece (e.g. sixty fluid jet cutting heads arranged in eight offset rows for the embodiment of FIG. 5A), thus allowing for all features to be simultaneously cut. However, decisions regarding size and arrangement of cutting heads should be weighed against other considerations such as, for example, fluid and/or abrasive material supply, reliability constraints, accessibility to each cutting head for maintenance, and motion system constraints.
Although the present invention has been described in considerable detail with reference to certain disclosed embodiments, the disclosed embodiments have been presented for purposes of illustration and not limitation and other embodiments of the invention are possible. One skilled in the art will appreciate that various changes, adaptations, and modifications may be made without departing from the spirit of the invention and the scope of the appended claims.

Claims

1. A fluid jet cutting system comprising:

a work bed adapted to receive and fixedly position a work piece;

a body having a plurality of fluid jet cutting heads installed therein, each fluid jet cutting head axially aligned with a jet axis and comprising a nozzle protruding from an exposed surface of the body, each fluid jet cutting head adapted to deliver a cutting stream from the nozzle toward the work piece;

a motion system, coupled about the work bed and adapted to move the body relative to the work piece;

a plurality of actuators coupled to the motion system and in fluid communication with the fluid jet cutting heads, each actuator configured to control delivery of pressurized fluid to one of the fluid jet cutting heads;

an intensifier configured to deliver the pressurized fluid to each actuator; and

a controller configured to control (i) the motion of the body relative to the work piece, and (ii) the delivery of the pressurized fluid to, and thereby an on/off state of, each of the fluid jet cutting heads such that a predetermined pattern can be cut from the work piece.

2. The fluid jet cutting system of claim 1, wherein the fluid jet cutting heads comprise abrasive fluid jet cutting heads, the fluid jet cutting system further comprising:

an abrasive material source adapted to deliver an abrasive material to the abrasive fluid jet cutting heads to be mixed with the pressurized fluid to form the cutting stream,

wherein the controller is further configured to control the delivery of abrasive material to the abrasive fluid jet cutting heads.

3. The fluid jet cutting system of claim 1, wherein each actuator comprises an actuator housing and is fluidly coupled with the fluid jet cutting heads via a length of tubing such that the actuator housing can be mounted so that it is not axially aligned with a jet axis defined by the cutting stream of the cutting head with which the actuator is associated.

4. The fluid jet cutting system of claim 1, wherein the body can be mounted to the motion system such that the cutting streams are delivered at an oblique angle relative to the work piece.

5. The fluid jet cutting system of claim 1, wherein the predetermined pattern comprises a plurality of identical, repeating features, spaced less than approximately 3.375 inches apart.

6. The fluid jet cutting system of claim 1, wherein the controller controls the on/off state of the fluid jet cutting heads such that adjacent features of the predetermined pattern are simultaneously cut by adjacent cutting streams.

7. A fluid jet cutting head mount comprising:

a body having a plurality of individually-actuated fluid jet cutting heads, each fluid jet cutting head configured, upon actuation, to deliver a cutting stream axially aligned with a jet axis of the fluid jet cutting head and oriented such that the cutting stream is delivered from an exposed surface of the body, wherein each fluid jet cutting head comprises:

a fluid inlet orifice axially aligned with the jet axis and in fluid communication with an intensifier configured to provide pressurized fluid to the fluid jet cutting head; and

a nozzle having an outlet channel axially aligned with the jet axis and terminating at a nozzle end from which the cutting stream is delivered.

8. The fluid jet cutting head mount of claim 7, wherein each fluid jet cutting head is individually-actuated by an actuator interposed between the fluid inlet orifice and the intensifier, each actuator being off-axis of the jet axis.

9. The fluid jet cutting head mount of claim 7, wherein the fluid jet cutting heads comprise abrasive fluid jet cutting heads, each fluid jet cutting head further comprising:

an abrasive feed inlet coupled with an abrasive source configured to provide abrasive material to the fluid jet cutting head; and

a mixing chamber aligned about the jet axis, interposed between the fluid inlet orifice and nozzle, and in fluid communication with the fluid inlet orifice, the abrasive feed inlet, and the outlet channel, wherein when actuated, the pressurized fluid from the fluid inlet orifice and the abrasive material from the abrasive feed inlet mix in the mixing chamber and are ejected from the fluid jet cutting head via the nozzle outlet channel thereby forming the cutting stream.

10. The fluid jet cutting head mount of claim 7, wherein the pressurized fluid comprises water.

11. The fluid jet cutting head mount of claim 7, further comprising a wear plate removably attached to the exposed surface of the body.

12. The fluid jet cutting head mount of claim 11, wherein the wear plate is magnetically mounted to the body.

13. The fluid jet cutting head mount of claim 9, wherein one or more of the abrasive feed inlets comprises an actuated abrasive feed inlet to selectively permit or deny communication of the abrasive feed inlet with the abrasive source.

14. The fluid jet cutting head mount of claim 7, wherein the body is configured to be mounted to a motion system.

15. The fluid jet cutting head mount of claim 14, wherein the body is configured to be mounted to the motion system such that one or more of the cutting streams is at an oblique angle relative to a surface a the work piece.

16. The fluid jet cutting head mount of claim 15, wherein the body is configured to be mounted such that one or more of the cutting streams is at an angle of approximately 25 degrees relative to the surface of the work piece.

17. The fluid jet cutting head mount of claim 14, wherein the nozzles protrude from the exposed surface of the body such that the distance between each nozzle end and the work piece is approximately the same.

18. The fluid jet cutting head mount of claim 7, comprising four fluid jet cutting heads.

19. The fluid jet cutting head mount of claim 18, wherein the fluid jet cutting heads are arranged in two rows and two columns within the body.

20. The fluid jet cutting head mount of claim 7, wherein one or more of the nozzles of the fluid jet cutting heads are depthwise offset within the body relative to one or more of the nozzles of the other fluid jet cutting heads.

21. The fluid jet cutting head mount of claim 7, wherein the jet axes are substantially parallel with one another.

22. The fluid jet cutting head mount of claim 7, wherein the plurality of fluid jet cutting heads are arranged in rows and columns generally perpendicular with the jet axes, adjacent cutting streams in each row being spaced less than 3.375 inches apart.

23. A method of cutting a plurality of identical features within a work piece comprising:

providing a fluid jet cutting system comprising:

a plurality of close-packed fluid jet cutting heads, each fluid jet cutting head delivering a cutting stream along a jet axis;

one or more intensifiers, for supplying pressurized fluid to the fluid jet cutting heads;

a plurality of actuators, each actuator in fluid communication with the one or more intensifiers and an associated fluid jet cutting head, each actuator configured to control an on/off state of the associated fluid jet cutting head and positioned such that it is not axially aligned with the jet axis of the associated fluid jet cutting head; and

a motion system, coupled to the fluid jet cutting heads, and configured to move the close-packed fluid jet cutting heads relative to the work piece;

installing the work piece within the fluid jet cutting system; and

activating the fluid jet cutting system thereby simultaneously cutting two or more features within the work piece.

24. The method of claim 23, wherein the work piece comprises a material sheet.

25. The method of claim 24, wherein the material sheet comprises a steel sheet.

26. The method of claim 23, wherein the step of activating the fluid jet cutting system comprises:

moving the fluid jet cutting heads relative to the work piece in a predetermined pattern while selectively activating two or more of the cutting heads.

27. The method of claim 23, wherein the close-packed fluid jet cutting heads are disposed within a body.