Methods and systems for plasma cutting holes and contours in workpieces

Abstract

An automated method for cutting at least one hole (300) in a workpiece using a plasma arc torch (103), wherein the method is implemented in a computer numerical control (115) and comprises: piercing the workpiece at a center point of the at least one hole (300) with the plasma arc torch (103); cutting an entry for the at least one hole (300) with a plasma arc generated by the plasma arc torch (103) extending from the center point to a circumferential edge of the hole (300), wherein the entry reaches the circumferential edge at or near an entry point, and at least one section of the entry is spiral-shaped;and cutting the circumferential edge of the hole (300) with the plasma arc with a first arc current value, wherein the circumferential edge is cut from the point where the insertion reaches the circumferential edge to the insertion point, wherein the spiral insertion (301) from the center point (P1) to the circumferential edge follows an arc path of at least 270 degrees, and wherein the workpiece is stainless steel.

Description

AREA OF INVENTION

[0001] The invention relates to an automated method for cutting at least one hole in a workpiece using a plasma arc torch according to claims 1 and 2, comprising an automated method for cutting at least one contour in a workpiece using a plasma arc torch according to claim 3, a plasma arc torch system according to claim 4, a computer-readable product that is tangibly embodied on an information carrier and that can be used in a computer-aided numerical control system to cut at least one hole in a workpiece with a plasma arc torch system according to claims 5 and 6, and a computer-readable product that is tangibly embodied on an information carrier and that can be used in a computer-aided numerical control system to cut at least one contour in a workpiece with a plasma arc torch system according to claim 7.Embodiments of the present invention generally relate to plasma arc cutting torch systems. More specifically, the embodiments relate to methods and systems for cutting internal holes and contours in a workpiece using a plasma torch tip system. TECHNICAL BACKGROUND OF THE INVENTION

[0002] Plasma cutting uses a focused electric arc to heat a gas stream to a plasma state, and the energy of the high-temperature plasma stream melts the workpiece at a specific point. Most cutting processes utilize a secondary gas stream (also known as a shielding gas stream or protective gas stream) to protect the torch and support the cutting process by helping maintain a stable arc. As the torch is moved relative to the workpiece, the plasma cuts the workpiece, leaving a desired hole or contour. However, depending on the shape or contour being cut, using a plasma cutting system can also have drawbacks. For example, the plasma may not always remain stable, which can result in defects on the surface of the cut section of the workpiece, such as angled or uneven surfaces.Although improvements have been made to cutting processes to limit these defects, disadvantages remain when using plasma in certain cutting situations because defects still occur. This is especially true when cutting small holes or contours.

[0003] Further limitations and disadvantages of conventional, traditional and proposed solutions can be recognized by the person skilled in the art by comparing such solutions with embodiments of the present invention, which are set out in the remainder of the present application with reference to the drawings. DESCRIPTION

[0004] To overcome the limitations and disadvantages, the following is described: an automated method for cutting at least one hole in a workpiece using a plasma arc torch according to claims 1 and 2; an automated method for cutting at least one contour in a workpiece using a plasma arc torch according to claim 3; a plasma arc torch system according to claim 4; a computer-readable product that is tangibly embodied on an information carrier and that can be used in a computer-aided numerical control system to cut at least one hole in a workpiece with a plasma arc torch system, according to claims 5 and 6; and a computer-readable product that is tangibly embodied on an information carrier and that can be used in a computer-aided numerical control system.to cut at least one contour into a workpiece using a plasma arc torch system, according to claim 7. Exemplary embodiments of the present invention include methods and systems for cutting holes and contours into workpieces using a plasma arc torch. The systems include a plasma arc torch, a power supply, CNC or other computer-aided control, motion devices, and a table. The methods include the use of an infeed cut, a geometry cut, and an overburn or outfeed cut, each with specific characteristics. The use of embodiments of the invention, as described in this text, results in improved hole and contour cuts that do not require secondary processing.

[0005] Further aspects and advantages of the invention can be seen from the following drawings and description, which all merely illustrate the principles of the invention by way of example. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The above-mentioned and / or further aspects of the invention will become more apparent by describing in detail exemplary embodiments of the invention with reference to the accompanying drawings, in which the following can be seen:

[0007] Fig. Figure 1 is a graphic representation of an exemplary embodiment of a plasma cutting system that can be used with embodiments of the present invention.

[0008] Fig. Figure 2 is a graphical representation of an operating flow diagram for an embodiment of the present invention;

[0009] Fig. 3A to Fig. 3D are graphical representations of a cutting process for a hole according to embodiments of the present invention;

[0010] Fig. Figure 4 is a diagrammatic representation of an exit path for a hole-cutting operation according to an embodiment of the present application;

[0011] Fig. Figure 5 is a diagrammatic representation of a cutting process for a contour according to an exemplary embodiment of the present invention; and

[0012] Fig. 6A and Fig. Figure 6B are graphical representations of other contours produced according to exemplary embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Exemplary embodiments of the invention are described below with reference to the accompanying figures. These exemplary embodiments are intended to facilitate understanding of the invention and are not meant to limit the scope of protection of the invention in any way. Identical reference numerals always refer to identical elements.

[0014] Embodiments of the present invention can be used for both holes and contours in workpieces. For the purposes of this text, holes have a shape that exhibits a diameter (or equivalent dimension) to workpiece thickness ratio of approximately 6:1 or less. That is to say, exemplary embodiments of the present invention can be used to form high-quality holes in workpieces with this ratio without deviating from the essence and scope of protection of the present invention.

[0015] Furthermore, embodiments of the present invention can be used in workpieces that have a thickness of up to 2 inches. It should be noted that holes with larger ratios are generally used in workpieces of greater thickness. In many applications of the present invention, the workpiece has a thickness of 1 inch or less. In such applications, holes typically have a diameter (or equivalent dimension) to thickness ratio of less than 3:1. That is, a circular hole in a workpiece 1 inch thick would have a diameter of approximately 3 inches or less.For the purposes of this text, holes can be categorized as small internal component structures that are not necessarily round, but are at least curved or have curved sections, such as ovals, ellipses, and other similar shapes, where the equivalent diameter of the hole (if the overall circumference were converted to a circle) has a diameter-to-thickness ratio of less than approximately 6:1. A contour is generally a larger cut structure in a workpiece and can include both straight and curved sections. It should be noted that although some shapes may have dimensions corresponding to or less than the aforementioned 6:1 ratio, they can still be considered contours due to their shape, such as squares, rectangles, etc.

[0016] As briefly discussed above, defects can occur when cutting holes, contours, and workpieces using plasma torches. Examples of such defects include the removal of too much material from the sides of the hole or contour, leaving protrusions on the wall that chamfer or taper the walls. These defects can be problematic in many workpieces and may necessitate a secondary process, such as drilling, or even the scrapping of the workpiece. In any case, the presence of these defects can result in significant costs and delays. Embodiments of the present invention eliminate such defects and enable highly efficient and precise cutting of holes and contours.Furthermore, embodiments of the present invention can be used with many different cutting systems using various plasma cutting components without deviating from the essence or scope of protection of the present invention.

[0017] Fig. Figure 1 shows an example plasma cutting system 100 The plasma torch system 100 includes a cutting table 101 and a plasma torch 103 The design and operation of cutting tables and plasma torches are generally known to those skilled in the art and will not be described in detail here. The system 100 It can also include a burner height control unit 105 use those connected to a portal system 107 The system can be mounted. 100 It can also be a drive system 109 contained, which is used to control the movement of the burner 103 relative to a workpiece that is on the table 101is positioned. A plasma cutting power supply 111 is with the burner 103 coupled to provide the required current used to generate the cutting plasma. The system 100 It can also be a gas console 113 It includes a component that can be used to regulate gas flow rates and pressures used during the cutting process for both the plasma and the shielding gas. The console 113 It can also be used to select different gases depending on the cutting process being performed. This means that certain gases can be used for some cutting operations but would not be used for others. The burner system 100 It also includes a computer numerical control (computer numeric controller, CNC). 115 , which includes a user input / display screen 117 may contain. The screen 117 and the CNC115 can be used by the user to enter and read cutting operating parameters and data, and to enable the system to 100 It can be used as an automated, programmable cutting system. Via the screen 117 (or another means) allows a user to input various parameters into the CNC, such as: torch current, material type, material thickness, cutting speed, torch height, plasma and shielding gas composition, etc. As stated above, the plasma system can 100 have many different configurations, and designs are not limited to those in Fig. The embodiment shown in 1, which is intended to be merely exemplary, is limited.

[0018] As is generally clear to the average expert, the CNC 115 any type of computer system that the system 100controls. As is generally known, a CNC has a processor, an electronic storage device, and an interface for transmitting control instructions to a plasma arc torch system. 100 The storage device can be internal or external and can contain data relating to the part to be cut in the workpiece. In other embodiments, the CNC 115 can be programmed manually, and in some versions the CNC 115 The product includes a computer-readable component containing computer-readable instructions that allow users to select or configure the operating parameters of the plasma torch system. In other exemplary embodiments, the computer-readable instructions may be cutting tables or nesting software. Such instructions typically contain cutting information that provides instructions for the system. 100This includes situations where different holes or contours are cut, taking into account the sizes and shapes of the holes and contours and the material being cut. As is generally understood, CNC can 115 It allows a user to cut numerous consecutive holes, contours, or a combination of holes and contours into a workpiece without interruptions between cuts. For example, the operator can select a cutting program that includes both hole and contour cutting instructions, and the CNC 115 determines the order and positioning of the cuts as well as the various parameters of the cuts based on the information entered by the user.

[0019] The user interface / screen 117 , who uses a computer 115The diagram illustrates a possible hardware configuration to support the systems and procedures described in this text, which serves as the control unit for the system. 100Of course, similar control unit-type systems can also be used to control and / or operate the systems described in this text. To provide additional context for various aspects of the present invention, the following discussion will give a brief, general description of a suitable computer environment in which the various aspects of the present invention can be implemented. Those skilled in the art will recognize that the invention can also be implemented in combination with other program modules and / or as a combination of hardware and software. In general, program modules include routines, programs, components, data structures, etc., that perform specific tasks or implement specific abstract data types.

[0020] Furthermore, it is obvious to those skilled in the art that the methods according to the invention can also be practiced with other computer system configurations, such as single-processor or multi-processor computer systems, minicomputers, mainframes, personal computers, handheld computers, microprocessor-based or programmable consumer electronics, and the like, each of which can be operatively connected to one or more associated devices. The illustrated aspects of the invention can also be practiced in decentralized computing environments, where certain tasks are performed by remote processing devices that are linked to each other via a communication network. In a decentralized computing environment, program modules can be arranged in both local and spatially separated storage devices.

[0021] The control unit of the system (for example) 115The invention can be implemented using an exemplary environment, including a computer, wherein the computer comprises a processing unit, system memory, and a system bus. The system bus connects system components, such as the system memory, to the processing unit. The processing unit can be any of the various commercially available processors. Dual microprocessors and other multiprocessor architectures can also be used as the processing unit.

[0022] The system bus can be any of several different bus structure types, such as a memory bus or memory controller, a peripheral bus, or a local bus, which can use any of a variety of commercially available bus architectures. System memory can include read-only memory (ROM) and random-access memory (RAM). A basic input / output system (BIOS) file, containing the basic routines that help transfer information between elements within the control unit, such as during startup, is stored in the ROM.

[0023] The control unit (for example) 115The control unit may also include a hard disk drive, a magnetic disk drive (for example, for reading or writing a removable disk), and an optical disk drive (for example, for reading a CD-ROM or other optical media). The control unit may contain at least one form of computer-readable medium. The computer-readable medium can be any available medium that the computer can access. Examples of computer-readable media include computer storage media and communication media. Computer storage media include volatile and non-volatile, removable and fixed media implemented in any method or technology for storing information, such as computer-readable instructions, data structures, program modules, or other data.Computer storage media include, for example, RAM, ROM, EEPROM, flash memory or other storage technologies, CD-ROM, Digital Versatile Disks (DVD) or other magnetic storage devices, or other media that can be used to store the desired information and that can be accessed by a user interface coupled to the control unit.

[0024] Communication media typically embody computer-readable instructions, data structures, program modules, or other data in a modulated data signal, such as a carrier wave or other transport mechanism; this includes all information transmission media. The term "modulated data signal" refers to a signal in which one or more of its properties are set or modified to encode information within the signal. Examples of communication media include wired media, such as a wired network or a direct-wired connection, and wireless media, such as acoustic, RF, infrared, and other wireless media. Combinations of the above also fall under the meaning of the term "computer-readable media."

[0025] A number of program modules can be stored in the drives and in RAM, including an operating system, one or more application programs, other program modules, and program data. The operating system is located in the computer or the user interface. 300 It can be any one of a number of commercially available operating systems.

[0026] Furthermore, a user can input commands and information into the computer via a keyboard and a pointing device, such as a mouse. Other input devices can include: a microphone, an infrared remote control, a trackball, a stylus, a joystick, a gamepad, a digitizing tablet, a satellite dish, a scanner, or similar devices. These and other input devices are often connected to the processing unit via a serial port interface coupled to the system bus, but they can also be connected via other interfaces, such as a parallel port, a game port, a Universal Serial Bus (USB), an IR interface, and / or various wireless technologies. A monitor or other type of display device can also be connected to the system bus via an interface, such as a video adapter.Visual output can also be achieved via a remote display network protocol, such as Remote Desktop Protocol, VNC, X Window System, etc. In addition to visual output, a computer typically includes other output peripherals, such as speakers, printers, etc.

[0027] A display can be equipped with a user interface that interacts with the control unit. 195The display, which is coupled to the processing unit, is used to present data received electronically from the processing unit. For example, the display can be an LCD monitor, a plasma monitor, a cathode ray tube monitor, etc., that electronically displays data. Alternatively or additionally, the display can also present received data in paper format, such as a printer, a fax machine, a plotter, etc. The display can show data in any color and can receive data from a user interface via any wireless or wired protocols and / or standards.

[0028] A computer can operate in a networked environment using logical and / or physical connections to one or more geographically dispersed computers. These computers can be workstations, servers, routers, personal computers, microprocessor-based entertainment devices, peer devices, or other shared network nodes, and typically include many or all of the elements described in relation to the computer. Logical connections shown include a local area network (LAN) and a wide area network (WAN). Such networked environments are now ubiquitous in offices, enterprise computer networks, intranets, and the internet.

[0029] When the computer is used in a networked LAN environment, it is connected to the local network via a network interface or adapter. When the computer is used in a networked WAN environment, it typically contains a modem, is connected to a communication server on the LAN, or has other means of establishing communication over the WAN, such as the internet. In a networked environment, program modules related to the computer or parts thereof may be stored on a remote storage device. It is understood that the network connections described in this text are examples and that other means of establishing communication between computers may also be used.

[0030] Fig. 2 shows a flowchart 200, which is achieved through exemplary embodiments of the present invention in conjunction with the CNC 115 can be used to generally operate the system 100 to describe. In an initial phase of the process, a component geometry is entered into the CNC. 115 loaded 201The component geometry can include the geometry of the entire workpiece and the geometry of the finished hole, contour, or part to be cut. This can be done manually by a user or automatically by other systems in a more automated process. It can also be done via a lookup table of various pre-programmed hole or contour shapes (for example, a circle), for which the user can then enter various parameters. For example, the user can select from a number of different shapes, such as circles or squares, and enter a parameter for the circle, such as its diameter or the length of a single side of the square. After the component geometry has been loaded, the material type and thickness of the workpiece to be cut are specified [...]. This data is then processed by the CNC. 115Used to determine the correct operating parameters for the cutting process. This will be discussed in more detail below. Following the input of material information. 203 It is determined whether the cut is a hole or a contour. 205 is or is not. This determination can be made manually by the user or automatically by the CNC. 115 The cut is made based on the entered data. This depends on whether the cut is for a hole or a contour. 205 is, uses the CNC 115 Various data and parameters are used to control the cutting process. If the cutting process involves a contour, the CNC uses... 115 Condition tables for contours 210 , which contain the data and parameter details for contour cutting. Using this data, the CNC sets the plasma parameters. 211 and the motion parameters 213for the cutting process, and then the system cuts 100 all contours that have the same dimensions 215 Of course, in other embodiments, the contours can also be cut individually one after the other. If there are no other structures to cut... 207 , thus the cutting process is terminated. 209 Similarly, if the shapes to be cut are holes, a different reference table is required. 220 used. The data / parameters from this table 220 are used to determine plasma parameters 221 and the motion parameters 223 to adjust, and then the holes are cut 225 CNC can also be used here. 115 You can cut all the holes that have the same diameter, or you can cut the holes one after the other.

[0031] We now turn to the Fig. 3A to Fig. Figure 3C, where each figure shows an entry path for cutting a hole structure according to an exemplary embodiment of the present invention. Thanks to the advantages of using the methods and systems described herein, hole structures can be cut with minimal defects and without the need for secondary machining of the holes, such as drilling, deburring, etc. Exemplary embodiments of the present invention can be used practically to form high-quality holes in mild steel workpieces where the hole diameter to material thickness ratio is ¾:1 or less, for workpiece thicknesses up to 1 inch, and in stainless steel workpieces where the hole diameter to material thickness ratio is 1:1 or less, for workpiece thicknesses up to 1 inch. In prior art cutting processes, such ratios required costly and inefficient secondary machining.In exemplary embodiments, screw-hole quality holes can be cut in mild steel up to a thickness of 2 inches, exhibiting a hole diameter to material thickness ratio in the range of 1 / 2:1 to 3 / 4:1, and screw-hole quality holes can be cut in stainless steel up to a thickness of 1 inch, exhibiting a hole diameter to material thickness ratio in the range of 3 / 4:1 to 1:1. Of course, larger diameter holes can also be cut, but these smaller ranges demonstrate the benefits of high precision in embodiments of the present invention. As is generally understood, screw-hole quality holes are holes cut for screws or other fasteners that are within the tolerances permissible for use with the fastener, without the need for secondary operations such as drilling.Prior to the embodiments of the present invention, such holes of screw hole quality could not be achieved without a secondary operation.

[0032] Fig. Figure 3A shows a first embodiment of an insertion cut to be used when cutting holes according to embodiments of the present invention. The hole 300 has a diameter D, which is the desired diameter for the hole 300 The first operation during hole cutting is to insert the workpiece at point P1. Typically, the insertion point P1 is located at the geometric center of the hole to be cut. 300 Before the workpiece is inserted, the CNC determines 115 The penetration time, the penetration point (for example, the center of the hole), and the kerf value for the plasma. Each of these parameters is based on the settings in the CNC. 115The input information, which may include material type, material thickness, hole diameter, plasma current, etc., determines the insertion point. In most embodiments, the insertion point P1 is located at the geometric center of the hole. 300 The penetration time depends on the type and thickness of the material. In exemplary embodiments of the present invention, the penetration time increases with the thickness of the material and the smaller the diameter D of the hole. Extending the penetration time for smaller diameter holes in thicker material results in a smoother transition from the initial cut to the hole geometry cut, which will be discussed in more detail below. Furthermore, the cutting gap value – i.e., the thickness of the cutting gap – is used to calculate the initial trajectory as it approaches or reaches P2, in order to achieve a smooth transition into the hole geometry.

[0033] As in Fig. Shown in 3A is the entry path. 301 a curved path, such that there is no abrupt transition from the entry path 301 to the cutting path 302 for the hole 300 There is. In the embodiment shown, the entry path has 301 an arc shape from the entry point P1 to the intersection point P2, which is the beginning of the hole geometry. In exemplary embodiments, the insertion path has 301 a semicircular shape with a constant radius. However, the entry path can 301 in other exemplary embodiments have an elliptical or oval shape, such that the radius of the insertion path 301 The distance from point P1 to point P2 is not constant. Furthermore, the feed rate or velocity of the arc in the entry path is not constant. 301 through CNC 115The machine is set and configured so that some additional material remains at the feed point transition to the hole geometry (point P2), preventing any hollowing out during the withdrawal process (which will be discussed in more detail below). More precisely, the feed rate for the insertion is determined by the CNC. 115The feed rate is determined based on material type, thickness, hole diameter, and cutting current, and is generally chosen so that some extra material remains at the transition from the feed point to the hole geometry P2. This differs from many known systems that remove all material at point P2. That is, a small protrusion—or excess material—may remain at point P2, which is removed at the end of the cutting process. In some exemplary embodiments, the feed rate is the same speed as the hole geometry feed rate (the speed at which the hole is cut). By keeping the feed rates between the feed point and the hole geometry at the same value, defects caused by speed transitions can be minimized. However, in other embodiments, the feed rate of the feed path is 301a different feed rate than the one for the hole geometry 302 This means that in some embodiments the feed rate of the insertion path is lower than the feed rate for the hole geometry, while in other embodiments it may be higher. For example, in many high-ampere applications ( 150Aor higher) it is useful that the insertion rate is higher than the hole geometry feed rate. Of course, this can also depend on the material used and its thickness. Exemplary embodiments of the present invention can use and optimize the difference – if any – between the insertion rate and the geometry cutting rate to avoid hollowing out the workpiece. That is, in some embodiments it is useful for the insertion rate to be faster than the geometry cutting rate to ensure that the torch does not hollow out the geometry wall, which can occur if the torch moves too slowly. Furthermore, in exemplary embodiments of the present invention, the cutting height for the torch is 103 in the introductory incision 301 set to the same height as the hole geometry path 302 is to be used.

[0034] Fig. Figure 3B shows another exemplary embodiment of an entry path. 301' / 301'' , which can be used. In this embodiment, a line-arc entry path is used, where the entry follows a line path. 301' and an archery path 301'' includes the arc path 301'' at point P2 regarding the hole geometry 302 transitions. In some embodiments – for example, when the hole diameter is larger relative to the workpiece thickness – a line-arc path can be used, with the first section of the insertion following a straight line. 301' is and the second section is an arc path 301'' from the line to the geometric point P2. Such an embodiment can shorten the cavity formation time by the arc near the circumferential edge of the hole geometry during insertion to ensure correct hole formation. This is because the radius of the arc segment 301''is smaller than if a full arc is used from the entry point P1 to the entry point P2, which makes the arc narrower and, in turn, makes the entry to the transition point P2 steeper. For example, such an embodiment could be advantageous when using higher current intensities with very thick materials and with holes that have a larger diameter. In such embodiments, the length of the line segment is 301' in the range of 35 to 65% of the length of a radius of the hole 300 The arc section can also be used here. 301'' of the entry path a constant or varying radius between the line segment 301' and the hole geometry point P2.

[0035] Fig. Figure 3C shows another exemplary embodiment of an inlet path. 301 , which can be used. In particular, it shows Fig. 3C an introduction path 301, which can be used with stainless steel materials. More precisely, it shows Fig. 3C a spiral entry path 301 , which has a greater length than arc or arc-line insertion paths. It has been found that when cutting holes in stainless steel workpieces – especially those with a thickness of at least 1 / 4 inch – out-of-roundness in the hole very often occurs, leaving uncut material burrs or protrusions. This often necessitates secondary processing, such as drilling or grinding. In embodiments of the present invention, the insertion path is extended to form a helical path. 301 to create a shape that ensures a higher heat input into the workpiece, resulting in improved hole geometry upon completion. This means the spiral feed. 301 It practically peels and heats the hole geometry 302This preheating occurs before the hole geometry is cut during the cutting pass. This preheating allows the hole geometry cutting pass to proceed more smoothly and predictably, resulting in a rounder hole and reducing the likelihood of excess material being left behind. The degree of helical feed depends on the hole diameter D, the material thickness, and the current. In exemplary embodiments of the present invention, the helical feed proceeds as follows: 301 through an arc path in the range of 240 to 720 degrees. (The in Fig. The embodiment shown in 3C shows an inlet. 301 (with a trajectory of 630 degrees). In some exemplary embodiments, the spiral inlet runs 301through an arc of at least 360 degrees. By extending the insertion path in this way, the workpiece can be preheated close to the hole geometry, and a round hole can be cut without the need for secondary machining. This is particularly true for stainless steel workpieces that are at least 1 / 4 inch thick, and when cutting holes with a diameter-to-thickness ratio of 2:1 or greater.

[0036] It should be noted that in each of the above introductory discussions, the introductory path 301 at point P2, the hole geometry is such that 302 overlooks the fact that the entry path at point P2 is approximately tangential to the hole geometry path. 302 The transition runs almost tangentially, differing from the entry point. 301 regarding hole geometry 302gentle. Furthermore, as mentioned above, in some exemplary embodiments the insertion path velocity and geometry are selected such that a small portion of excess material is present at point P2, as shown in Fig. Shown in 3D. As shown in this figure, the entry path overlaps. 301 not with the circumferential edge 302The entry point is not exactly at P2, but close to it. This leaves some excess material radially inward and downstream (in the feed direction) of P2, as shown. The presence of this excess material prevents hollowing out during the exit or overburn phase of the cut (which will be discussed further below). That is, in some applications, the presence of this excess material helps prevent the arc from hollowing out the workpiece as it completes the circumferential geometry and enters the exit or overburn phase of the cut.

[0037] After the insertion and cutting process ( 301 ) the cutting process proceeds to the hole geometry cut 302 forward (see Fig. 3A to Fig. 3C). During the hole geometry cut 302 The CNC controls 115The cutting height, cutting speed, current, shielding gas pressure, and kerf value are adjusted to achieve the desired cutting dimensions. Based on the input data, the CNC machine then... 115 the correct cutting height for the burner 103 one that is generally kept constant during the cutting process. Furthermore, the CNC determines 115 It determines and sets a cutting speed for the hole geometry based on user input data. For example, the CNC takes into account 115 The hole diameter D, the material type, the material thickness, and the cutting current used for the plasma are all important factors. It should be noted that if the cutting speed is too high, the hole may have an undesirable taper, whereas if the cutting speed is too slow, the cut surface on the workpiece and the bottom edge of the hole may be distorted. Furthermore, the CNC machine adjusts and controls these parameters. 115the protective gas pressure during the hole geometry cutting 302 to ensure a smooth and precise cut. Adjusting or changing the shielding gas pressure at the entry cut. 301 up to the hole geometry cut 302 This is used to control the taper or bevel of the cut. Reducing the shielding gas pressure generally results in a positive bevel on the cut edge. Therefore, embodiments of the present invention use a reduced shielding gas pressure during the cutting of the hole geometry. 302 , to compensate for the normal chamfering that can occur when cutting holes, thereby optimizing the hole cutting. In some exemplary embodiments, the chamfering occurs during the cutting of the hole geometry. 302 The shielding gas pressure used was the same as that used for the insertion cut. 301used, while in other exemplary embodiments the protective gas pressure is reduced in such a way that it is smaller than that during the insertion. 301 The shielding gas pressure used is also determined by the CNC. In addition to the above, the cutting gap value for the cutting process is also determined by the CNC. 115 controlled and adjusted to ensure that the correct hole size is obtained.

[0038] Fig. Figure 4 shows an exemplary embodiment of a lead-out cut that can be used with embodiments of the present invention. Many known systems extinguish the cutting arc when or before the torch 103 Point P2 has been reached. However, this process can leave protrusions in the hole that require secondary machining. Embodiments of the present invention eliminate the need for secondary machining by using a lead-out section. 401, as described in the present text. The excerpt section 401 follows the same path as the corresponding hole geometry section, such that the paths of each section overlap, as in Fig. 4 shown.

[0039] More precisely, embodiments of the present invention use an overburn distance to determine an arc cut-off time value, which is used to control the power supply. 111to instruct the plasma flow to be switched off at a time before the completion of exit point P3, and to determine point P3 at which the exit section is completed. This determination allows the arc to remain lit as the torch moves past point P2 and exits to point P3. That is, embodiments of the present invention use arc overburning to ensure a smooth transition upon completion of the hole-cutting operation. This is described below in conjunction with Fig. 4 explained in more detail.

[0040] The CNC contains data for each cutting operation. 115Overburn distances for various cutting operations, wherein the overburn distance is a distance from the hole geometry entry point – P2 – to an overburn point Po, wherein during the overburn distance the plasma arc is maintained at or near its cutting thickness used during the hole geometry cutting. In some exemplary embodiments, the cutting current is supplied by the power supply 111 The cutting current is maintained at or near the cutting current level for the hole geometry cutting. In some exemplary embodiments, the current remains at the same level. However, in other exemplary embodiments, the cutting current is controlled by the power supply. 111 The cutting current is kept within 20% of the cutting current during the overburn distance. For example, if the primary cutting current is 100 A, the power supply can be... 111 Reduce the current to 80 A during the overburn distance. The overburn distance is determined by the CNC.115 used to provide an arc-stop time signal for the power supply 111 to determine, in such a way that the power supply 111 The cutting current can be switched off so that the arc is completely extinguished before or at the point where the torch reaches point P3. The overburn distance and the arc extinguishing signal are provided by the CNC. 115 used to ensure that an arc is still present when the burner 103 The entry point P2 is passed to complete the hole geometry. However, it should be noted that in some exemplary embodiments the CNC 115 can use the overburn distance and the arc cut-off time signal to control the cutting current in such a way that the cutting current is supplied by the power supply 111 is reduced or switched off before the burner 103The torch has reached the entry point P2, but due to inherent arc-shutdown delay times, the arc may still be present when the torch passes the entry point P2 as it moves towards the exit point P3. This is explained in more detail below.

[0041] In exemplary embodiments of the present invention, the overburn distance for each cutting operation is set based on various parameters, including any combination of hole diameter D, feed rate, material thickness, material type, and arc current. In exemplary embodiments of the present invention, the CNC stores 115Various preset overburn distances are available for different cutting operations and parameters, such that when a user enters various process information, an overburn distance is determined. Such data can include hole diameter D, material thickness, material type, and cutting plasma flow. For example, the CNC determines 115 After a user has entered the input parameters for a cutting operation, the overburn distance to be used for the entire hole-cutting operation is determined. This determination can be made using lookup tables, algorithms, or other similar methodologies available in the CNC. 115are stored. For example, in some exemplary embodiments, the longer the overburning distance used, the larger the diameter D of the hole to be cut. In exemplary embodiments of the present invention, the overburning distance is in the range of 0.01 to 0.3 inches. In other exemplary embodiments, the overburning distance can be in the range of 0.02 to 0.1 inches. As a rule, the overburning distance is longer the thicker the workpiece and the larger the hole.

[0042] Once the overburning distance is determined, the CNC determines 115 Then the overburn time. The overburn time is determined by dividing the overburn distance by the hole geometry feed rate (ipm) / 60. That is: Overburn time = (Overburn distance / (Hole geometry-feed rate / 60))

[0043] The CNC 115The overburn time is then used to determine an arc cut-off time value. This arc cut-off time value is used to determine the endpoint P3 of the exit section. 401 used – the time at which the cutting process is completed and the movement of the torch 103 can be terminated. In exemplary embodiments of the present invention, the CNC uses 115The specified overburn time, together with other parameters, is used to determine the endpoint P3. For example, embodiments of the present invention can also incorporate an arc delay time and / or an arc cut-off time. The arc delay time is a predetermined delay time representing the arc delay of the power supply. That is, the arc delay time is the time the plasma arc needs to respond essentially to a change in the output current from the power supply—for example, due to system inductance. The arc cut-off time is a predetermined time it takes for an arc to extinguish after the current from the power supply has been switched off. The arc cut-off time is a predetermined value that is a function of the power supply and the cutting current level.In exemplary embodiments of the present invention, the arc delay time is in the range of 0.05 to 0.2 seconds, and the arc cut-off time is in the range of 0.125 to 0.6 seconds.

[0044] Therefore, in some exemplary embodiments, the arc cut-off time value is determined by summing the specified overburn time, arc delay time, and arc cut-off time. This summed arc cut-off time value (in seconds) is used in conjunction with the feed rate of the operation to determine the endpoint P3 of the exit section. 401 used. The CNC controls the arc cut-off time using this specific value. 115 the operation of the system 100 , including the movement of the burner 103 , such that the burner 103The process stops at point P3. In exemplary embodiments of the present invention, the endpoint P3 lies in the range of 20 to 35 degrees radially beyond point P2.

[0045] By using the systems and methods described above, embodiments of the present invention can produce highly precise holes in workpieces that do not require secondary machining to complete the holes.

[0046] In addition to enabling the production of high-quality holes, embodiments of the present invention are capable of producing highly precise contours that do not require secondary machining. Besides causing defects in cutting holes, known systems can also cause defects when cutting contours. Such defects may include protrusions or excess material that require grinding to complete the part or contour. Embodiments of the present invention can produce contours without the need for such secondary machining.

[0047] Fig. Figure 5 shows an exemplary contour that can be cut using embodiments of the present invention. It should be noted that the contour shown in Figure 5 is an exemplary contour that can be cut using embodiments of the present invention. Fig. Although the contour shown in Figure 5 is a rectangle, embodiments of the present invention are not limited to this, as other shapes can also be cut without deviating from the essence or scope of protection of the present invention. Furthermore, exemplary systems such as the one shown in Figure 5 can be used. Fig. 1 system shown 100 They can be used for cutting contours, as described in the present text.

[0048] As shown, the contour 500 an introductory section 501 , which extends from the entry point P1 to the beginning of the component geometry path P3. As in Fig. As shown in section 5, the introductory section can be 501a straight line. However, in other embodiments, depending on the shape of the contour, it may be desirable to use a curved or arc-shaped inlet. There are no restrictions in this respect for the embodiments. Once the inlet 501 The system cuts when it is cut. 100 the component geometry path 503 following the desired geometry for the part 500 In exemplary embodiments, the inlet section 501 and the geometry path section 503The same cutting parameters are used, such as speed, cutting height, current level, voltage, current, etc. As is generally understood, the parameters for the cutting process are specified and determined by user input information, such as material thickness, material type, current, etc. When the geometry path segment reaches a transition point P2, which is located at a point just before completion of the desired contour, the cutting process enters a deceleration phase. 505 , during which the CNC 115 the feed rate for the burner 103 slowed down and the burner height control or arc voltage height control (both of which are commonly known) of the system 100 blocked, which are used to control the height of the burner 103to maintain the arc height during the operation. The structure and operation of height control systems, often referred to as torch height control or arc voltage height control circuits or systems, are well-known in the automated plasma cutting industry and need not be described in detail here. Blocking or disabling the system's height control (which can be done in the CNC, the power supply, or both) is particularly advantageous in materials like stainless steel due to arc retardation during cutting. Slowing the feed rate helps keep the arc nearly vertical throughout the cut, but if the voltage height control remains on, it causes the torch to tilt. 103as the torch moves closer to the workpiece and eventually touches it. Therefore, the torch is slowed down, and its height control mechanism or function is deactivated, so that the torch... 103 not through CNC 115 is controlled to adjust the deceleration, which can cause the burner to 103 against the workpiece. In exemplary embodiments of the present invention, the feed rate during the deceleration phase is 505 in the range of 25 to 45% of the feed rate for the geometry path section 503 In some exemplary embodiments, the feed rate is in the range of 30 to 36% of the feed rate for the geometry path section. 503 the contour 500 This is particularly advantageous for stainless steel workpieces.

[0049] Furthermore, as in Fig. Figure 5 shows the transition point P2 along the circumferential edge of the contour near the endpoint P3 of the contour. 500 arranged. That is, the transition point P2 is near the end of the cutting process for the contour. 500 arranged. In exemplary embodiments, the transition point P2 lies in the range of 80 to 99% of the total circumferential length of the contour. 500 In other exemplary embodiments, the transition point P2 lies in the range of 90 to 98% of the total circumferential length of the contour. 500 In many exemplary embodiments, the distance between P2 and P3 is typically in the range of 0.125 to 0.5.

[0050] In other exemplary embodiments, the distance is in the range of 0.25 to 0.4 inches. Factors that can influence the optimal distance between P2 and P3 include arc current and material thickness. By ensuring a sufficient distance for the deceleration section 505By selecting the contour path, a particularly clean cut is created at transition point P3 at the end of the contour cutting process. 500 .

[0051] Furthermore, as in Fig. 5 shown, after the burner 103 has reached point P3 to complete the contour, the burner 103 from the contour in a leading section 507 at an angle A relative to the deceleration section 505 the contour 500 withdrawn. Angle A allows the burner 103 , to make a sharp turn at point P3, which causes the cutting plasma to remove any burrs or excess material that remained at point P3 when using older systems. This is particularly effective when the contour 500 is cut in stainless steel workpieces. In exemplary embodiments, the exit section 507with the same feed rate and control settings as for the deceleration section 505 executed. This applies in particular to the initial phases of the extraction section. 507 In some exemplary embodiments, after the torch has been moved away from the vicinity of the transition point P3, the speed or other parameters of the cutting process can be changed before the endpoint of the cut P4. Furthermore, in exemplary embodiments of the present invention, the angle A is in the range of 20 to 40 degrees. In other exemplary embodiments, the angle A is in the range of 28 to 32 degrees, and in some exemplary embodiments, the angle is 30 degrees. It should be noted that the angle A, which determines the direction of the exit section 507 prescribes that measurement is taken from a line running along the path of the end of the deceleration section 505lies when the deceleration section 505 The intersection point P3 overlaps. Fig. 5 this line lies along the same line as the deceleration section. 505 about the length of the deceleration section 505 away (because it's a straight line). The Fig. 6A and Fig. Figure 6B shows other exemplary embodiments where the contour is not a rectangular shape, as in Fig. 5 shown. In Fig. 6A is a section of the contour 500 a semicircle such that the line L, from which the angle A is measured, lies along the tangent of the semicircular section at the intersection point P3. Fig. 6B shows the slowdown section 505 , which has at least two line segments. Therefore, the orientation of line L coincides with the line segment that intersects the transition point P3. This ensures that the exit 507is executed at an angle that is sharp enough to produce a sharp and clean corner at the transition point P3.

[0052] As explained previously, the techniques described above can be used in CNC machining. 115 or any other computer-controlled system using digital electronic circuits or in computer hardware, firmware, software, or combinations thereof. The implementation can take the form of a computer program product, that is, a computer program tangibly embodied on an information carrier (for example, a CPS). An information carrier can be a machine-readable storage device or can be in the form of a propagated signal to be executed by, or to control the operation of, processing devices (for example, a programmable processor, a computer, or multiple computers).

[0053] A computer program (for example, a computer program system) can be written in any form of programming language, including compiled or interpreted languages, and it can be used in any form, including as a standalone program or as a module, component, subroutine, or other unit suitable for use in a computer environment. A computer program can be used to run on a single computer or on multiple computers, at one location or distributed across multiple locations and interconnected by a communication network.

[0054] Process steps can be executed by one or more programmable processors that run a computer program to perform functions of the invention based on input data and generate an output signal. Process steps can also be executed by specialized logic circuits, and devices can also be implemented as specialized logic circuits, such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit). Modules can refer to sections of the computer program and / or to the processor or specialized circuits that implement this functionality.

[0055] Processors suitable for executing a computer program include, for example, general-purpose and specialized microprocessors, and one or more processors of any type of digital computer. Generally, a processor receives instructions and data from read-only memory, random-access memory, or both. The essential elements of a computer are a processor for executing instructions and one or more memory components for storing instructions and data. A computer also generally includes, or is operatively connected to, one or more mass storage devices for storing data, such as magnetic, magneto-optical, or optical disks, for receiving or sending data, or both.Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including, for example, semiconductor memory chips such as EPROM, EEPROM, and flash memory chips; magnetic disks such as internal hard drives and removable storage devices; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and memory may be supplemented by or integrated into specialized logic circuits.

[0056] To enable user interaction, the techniques described above could be implemented on a CNC machine or computer equipped with a display device, such as a cathode ray tube (CRT) or liquid crystal display (LCD) monitor, to show information to the user, and a keyboard and pointing device, such as a mouse or trackball, with which the user can input information into the computer (for example, interact with a user interface element). Other types of devices could also be used to enable user interaction. For example, feedback to the user could take any form of sensory feedback, such as visual, auditory, or tactile feedback; and input from the user could be received in any form, including auditory, speech, or tactile input.

[0057] The techniques described above can be implemented in a decentralized computing system that includes a back-end component, such as a data server; a middleware component, such as an application server; a front-end component, such as a client computer with a graphical user interface or a web browser through which a user can interact with the implementation; or any combination of such back-end, middleware, or front-end components. The system components can be connected by any form or medium of digital data communication, such as a communication network. Examples of communication networks include a local area network (LAN), a wide area network (WAN), and the internet.

[0058] "Include," "contain," and / or their plural forms are open-ended phrases and contain the listed parts and may include further parts not listed. "And / or" is an open-ended phrase and contains one or more of the listed parts and combinations thereof.

[0059] Although the invention has been shown and described specifically with reference to concrete exemplary embodiments, it is understood that various changes in form and detail can be made to it without deviating from the essence and scope of protection of the invention. Reference symbol list 100 System 101 Cutting table 103 plasma torches 105 Control unit 107 Portal system 109 Drive system 111 Power supply 113 Console 115 Computer-aided numerical control 117 screen 200 Flowchart 201st level 203rd level Level 205 207th level 209th level 210 level 211th level 213th level 215th level 220 level 221st level 223rd level 225 level 300 user interface / hole 301 Entry Path 301 / 301'' path 302 Cutting thread / geometry Section 401 500 contour Section 501 Path 503 Section 505 Section 507 A Angle CNC Computer-aided numerical control Diameter L line P1 point P2 point P3 point P4 point

Claims

[1] Automated method for cutting at least one hole in a workpiece using a plasma arc torch, wherein the method is implemented in a computer-aided numerical control system and comprises: Piercing the workpiece at the center point of at least one hole with the plasma arc torch; Cutting an entry point for the at least one hole with a plasma arc generated by the plasma arc burner, extending from the center point to a circumferential edge of the hole, wherein the entry point reaches the circumferential edge at or near an entry point, and at least one section of the entry point has an arc shape; Cutting the circumferential edge of the hole with the plasma arc at a first arc current value, wherein the circumferential edge is cut from the point where the insertion reaches the circumferential edge to the insertion point, and After the plasma arc torch has reached the entry point, maintain the plasma arc at the plasma arc torch for an overburn distance past the entry point and move the plasma arc along the circumferential edge past the entry point with a second arc current. where the second arc current is at or near the first plasma arc current, and where, after the overburn distance, the second arc current is switched off and the plasma arc torch is moved along the circumferential edge until the plasma arc is completely extinguished. [2] Automated method for cutting at least one hole in a workpiece using a plasma arc torch, wherein the method is implemented in a computer-aided numerical control system and comprises: Piercing the workpiece at the center point of at least one hole with the plasma arc torch; Cutting an entry point for the at least one hole with a plasma arc generated by the plasma arc torch, extending from the center point to a circumferential edge of the hole, wherein the entry point reaches the circumferential edge at or near an entry point, and at least one section of the entry point is helical; and Cutting the circumferential edge of the hole with the plasma arc at a first arc current value, wherein the circumferential edge is cut from the point where the insertion reaches the circumferential edge to the insertion point, wherein the inlet runs at least 270 degrees from the center point to the circumferential edge, and the workpiece is made of stainless steel. [3] Automated method for cutting at least one contour into a workpiece using a plasma arc torch, wherein the method is implemented in a computer-aided numerical control and comprises: Piercing the workpiece at a point that is away from a circumferential edge of the contour; Cutting an entry point for the at least one contour with a plasma arc generated by the plasma arc torch, extending from the entry point to an entry point on the circumferential edge of the contour; Cutting a first section of the circumferential edge with the plasma arc using a first arc current value and a first feed rate, until the plasma arc reaches a transition point along the circumferential edge, which is located just before the entry point; Cutting a second section of the circumferential edge with the plasma arc at a second feed rate that is lower than the first rate, from the transition point to the entry point; and Cutting an outfeed with the plasma arc, extending from the entry point to an endpoint located away from the circumferential edge, wherein, during the cutting of the second section, the plasma arc torch is held at a constant height above the workpiece, and wherein the exit is cut at an angle relative to a line that coincides with the second section when the second section reaches the entry point, the angle being in the range of 20 to 40 degrees. [4] Plasma arc burner system ( 100 ), which is configured to contour ( 500 ) and holes ( 300) to cut workpieces of different thicknesses and material types in various shapes and sizes, using the plasma arc burner system ( 100 The following is included: a plasma arc burner ( 103 ), which receives a plasma arc current and generates a plasma arc current to cut a workpiece; and a computer-aided numerical control ( 115 ), which is configured for the following: Selecting a piercing point in the workpiece with the plasma arc torch ( 103 ); Select from several insertion cutting geometries, a first insertion geometry used for insertion into hole geometries, and a second insertion geometry used for insertion into contour geometries, Select from several geometry cutting speeds, a geometry cutting speed based on at least one workpiece thickness; and Select from several extraction cutting geometries, a first extraction configuration when extracting from hole geometries, and a second extraction geometry when extracting from contour geometries. where, for the first exit configuration, after the plasma arc torch has reached an entry point of the first entry geometry, the computer-aided numerical control ( 115 ) a plasma arc at the plasma arc burner ( 103 ) maintains an overburn distance past the entry point and directs the plasma arc along a circumferential edge of the hole ( 300 ) past the entry point with a second arc current, and wherein, after the overburn distance, an arc current flows to the plasma arc burner (103 ) is switched off and the plasma arc burner ( 103 ) is moved along the circumferential edge until the plasma arc is completely extinguished, and where, for the second exit geometry, after the plasma torch has reached an entry point for the second entry geometry, the computer-aided numerical control ( 115 ) the plasma arc at the plasma arc burner ( 103 ) for an exit section extending from the entry point, wherein the exit is at an angle relative to a line formed by the circumferential edge of the contour ( 500 ) coincides, at the point of entry the cut is made at the end of the formation of the circumferential edge, and the angle is in the range of 20 to 40 degrees. [5] A computer-readable product that is tangibly embodied on an information carrier and that is used in a computer-based numerical control system (115 ) can be used for this purpose, at least one hole ( 300 ) into a workpiece with a plasma arc torch system ( 100 ) to cut, wherein the computer-readable product contains instructions that serve to control the computer numerical control ( 115 ) to initiate the following: Piercing the workpiece at the center point of at least one hole ( 300 ) with the plasma arc burner ( 103 ); Cutting an inlet for the at least one hole ( 300 ) with a plasma arc burner ( 103 ) generated plasma arc, which extends from the center to a circumferential edge of the hole ( 300 ) extends, wherein the insertion reaches the circumferential edge at or near an insertion point, and at least one section of the insertion has an arc shape; Cutting the circumferential edge of the hole ( 300) with the plasma arc with a first arc current value, wherein the circumferential edge is cut from the point where the insertion reaches the circumferential edge to the insertion point, and after the plasma arc burner ( 103 ) has reached the insertion point, maintaining the plasma arc at the plasma arc torch ( 103 ) for an overburn distance past the entry point and movement of the plasma arc along the circumferential edge past the entry point with a second arc current, where the second arc current is at or near the first plasma arc current, and where, after the overburn distance, the second arc current is switched off and the plasma arc burner ( 103 ) is moved along the circumferential edge until the plasma arc is completely extinguished. [6] A computer-readable product that is tangibly embodied on an information carrier and that is used in a computer-based numerical control system ( 115 ) can be used for this purpose, at least one hole ( 300 ) into a workpiece with a plasma arc torch system ( 100 ) to cut, wherein the computer-readable product contains instructions that serve to control the computer numerical control ( 115 ) to initiate the following: Piercing the workpiece at the center point of at least one hole ( 300 ) with the plasma arc burner ( 103 ); Cutting an inlet for the at least one hole ( 300 ) with a plasma arc burner ( 103 ) generated plasma arc, which extends from the center to a circumferential edge of the hole ( 300) extends, wherein the insertion reaches the circumferential edge at or near an insertion point, and at least one section of the insertion is spiral; and Cutting the circumferential edge of the hole ( 300 ) with the plasma arc with a first arc current value, wherein the circumferential edge is cut from the point where the insertion reaches the circumferential edge to the insertion point, wherein the inlet runs at least 270 degrees from the center point to the circumferential edge, and the workpiece is made of stainless steel. [7] Computer-readable product that is tangibly embodied on an information carrier and that is used in a computer-based numerical control system ( 115 ) can be used to create at least one contour ( 500 ) into a workpiece with a plasma arc torch system ( 100) to cut, wherein the computer-readable product contains instructions that serve to control the computer numerical control ( 115 ) to initiate the following: Piercing the workpiece at a point defined by a circumferential edge of the contour ( 500 ) is located away; Cutting an inlet for at least one contour with a plasma arc torch ( 103 ) generated plasma arcs that extend from the insertion point to an insertion point on the circumferential edge of the contour ( 500 extends; Cutting a first section of the circumferential edge with the plasma arc using a first arc current value and a first feed rate, until the plasma arc reaches a transition point along the circumferential edge, which is located just before the entry point; Cutting a second section of the circumferential edge with the plasma arc at a second feed rate that is lower than the first rate, from the transition point to the entry point; and Cutting an outfeed with the plasma arc, extending from the entry point to an endpoint located away from the circumferential edge, during the cutting of the second section, the plasma arc torch ( 103 ) is held at a constant height above the workpiece, and wherein the exit is cut at an angle relative to a line that coincides with the second section when the second section reaches the entry point, the angle being in the range of 20 to 40 degrees.