JP2022504056A - Consumable cartridge for plasma arc cutting system - Google Patents

Abstract

A frame for a single replaceable consumable cartridge configured to be installed on a plasma arc torch. The frame includes a hollow body adapted to receive a translationally movable contact initiation electrode. The body has an inner surface and an outer surface. The body consists of a substantially cylindrical metal core, an electrically insulating overmolded plastic casing that at least substantially surrounds the tip of the substantially cylindrical metal core, and a hollow body. It has a set of flow paths that fluidly connect the outer surface and the inner surface of the hollow body. The flow path is offset to impart a swirling fluid flow pattern to the passing plasma gas.

Description

The present invention generally relates to the fields of plasma arc cutting systems and processes. More specifically, the invention relates to methods and devices for simplifying, optimizing, and reducing cutting time and costs through the use of improved consumable cartridges.

Plasma arc torches are widely used for cutting and marking materials. Plasma torches typically include an arc emitter (eg, an electrode), an arc contractor or contractor (eg, a nozzle) with a central outlet orifice mounted within the torch body, electrical connections, and cooling passages. , Includes passages for arc control fluids (eg, plasma gas). The torch produces a contracted ionized jet of gas at high temperature and high momentum. The gas used in the torch can be a non-reactive gas (eg, argon or nitrogen) or a reactive gas (eg, oxygen or air). During operation, the pilot arc is first generated between the arc emitter (cathode) and the arc contractor (anode). Pilot arc generation can be done using either high frequency, high voltage signals connected to DC power supplies and torches, or various contact starting methods.

Known consumables suffer from many shortcomings both before and during the cutting operation. Before the cutting operation, selecting and installing the correct set of consumables for a particular cutting task can be tedious and time consuming. During operation, current consumables face performance issues such as the inability to effectively dissipate and conduct heat from the torch and the inability to maintain proper consumable alignment and spacing. In addition, existing consumables contain significant amounts of expensive materials such as copper and / or Vespel®, which are costly to manufacture and prevent widespread commercialization, manufacture and adoption. What is needed is to reduce manufacturing costs, increase system performance (eg, component alignment, cutting quality, consumable life, versatility / versatility, etc.) and end-user installation and use of consumables. A new and improved consumable platform that simplifies.

The present invention provides one or more cost-effective cartridge designs that reduce manufacturing costs, simplify commercialization and production of cartridges, improve end-user installation and usability, and improve system performance. .. In some embodiments, a number of conventional consumable parts (eg, swirl rings, nozzles, shields, holding caps, and electrode parts) have been redesigned. In some embodiments, new parts (eg, electrode sleeves, lock rings, and / or interface insulators) are created. In some embodiments, the conventional swirl ring is replaced with a different feature within the torch body that vortexes the gas flow within the torch body (eg, a swirl mechanism with a flow hole built directly into the nozzle body). In some embodiments, the nozzle shield is electrically isolated from the nozzle (eg, by using anodized aluminum and / or plastic).

In some embodiments, each cartridge comprises one or more of the following consumable parts: A frame or body with one or more sections, an arc emitter (eg, an electrode), an arc shrinker or arc shrink member (eg, a nozzle), a mechanism that swirls the gas in a plasma torch (eg, incorporated into a nozzle). A swirl mechanism, a swirl ring, or another swirl mechanism), a shield (eg, a nozzle shield electrically insulated by the use of aluminum, anodized aluminum, and / or plastic material), a radiating element (eg, a hafnium radiator). ), And / or end cap. In some embodiments, the cartridge comprises a substantially copper portion (eg, an inner core of copper) and a substantially non-copper portion (eg, a non-copper portion outside the inner core). In some embodiments, the cartridge can be used in a handheld plasma cutting system and / or a mechanized plasma cutting system.

In some embodiments, the cartridge has an elastic element, such as a spring electrode or a spring start mechanism secured to the electrode, which is designed to be integrated directly into the cartridge and not separate or disassembled from the cartridge. Has been done. The elastic element can be physically communicated with the frame and / or configured to carry a pilot current from the frame to the arc emitter. The elastic element can urge the arc emitter in a direction along the axis of the elastic element, for example, by applying a separating force. In some embodiments, the separating force has a magnitude less than the magnitude of the binding force that holds the cartridge together.

In some embodiments, the cartridge has enhanced cooling and insulation capabilities, reduced manufacturing and material costs, and / or improved recyclability, durability and performance. In some embodiments, the cartridge provides consumable parts in one integrated part. In some embodiments, the cartridge makes it possible to significantly reduce the installation time of the torch (eg, one-fifth to one-tenth), and the fitting part is always available for a given cutting operation. Proper selection, improved heat dissipation and / or heat transfer performance, easy recognition of consumable parts suitable for a particular cutting operation, consumable alignment and / or consumable spacing Allows and / or reduces operator error. In some embodiments, heat is transferred substantially away from the torch, but not enough to heat or melt the plastic part. In some embodiments, the use of metals other than copper (eg, in the outer region of the inner core of the copper component) helps keep heat away from the torch. In some embodiments, the cartridge allows preselection of a particular combination of consumables for a particular cutting operation.

In some embodiments, the cartridge frame comprises a highly thermally conductive material, such as aluminum, copper, or another highly conductive metal. In some embodiments, the cartridge frame is formed by molding. In some embodiments, at least one of the first end of the cartridge frame or the second end of the frame comprises a threaded region formed to engage complementary parts. In some embodiments, the shield, arc contractor, and frame are thermally coupled. In some embodiments, the outer surface of the frame is formed to connect to the retaining cap. In some embodiments, the cartridge comprises a shielded insulator connected to a frame. In some embodiments, the shield insulator is press-fitted into the frame.

In some embodiments, the cartridge cap defines an opening of the arc emitter and includes a fluid seal surface arranged around the circumference of the arc emitter opening. In some embodiments, the electrodes include springs. In some embodiments, the cartridge cap extends within the base region of the arc shrink member to a position near the set of swirl holes. In some embodiments, the base of the arc shrink member is formed by molding. In some embodiments, a retaining cap is connected to the cartridge body. In some embodiments, the retaining cap comprises plastic. In some embodiments, the arc shrink member and the electrode are connected to the holding cap via the base of the arc shrink member.

In some embodiments, the cartridge comprises a shield connected to the cartridge body. In some embodiments, the shield is connected to the cartridge body via a shield insulator. In some embodiments, the shield insulator is press-fitted into at least one of the shields or the base of an arc shrink member. In some embodiments, the shield insulator is electrically insulating. In some embodiments, the shielded insulator is thermally conductive. In some embodiments, the shielded insulator comprises anodized aluminum. In some embodiments, the sleeve is placed around a portion of the electrode. In some embodiments, the sleeve comprises an anodized layer formed to electrically insulate the electrodes from the base of the arc shrink member. In some embodiments, the sleeve comprises a set of flow surfaces configured to facilitate the flow of fluid within the plasma torch, eg, to improve cooling.

In some embodiments, the cartridge (or consumable assembly) comprises a seal placed within the cap insert. In some embodiments, the cartridge comprises a holding cap directly connected to the gas flow diverter. In some embodiments, the retaining cap is made of plastic. In some embodiments, the arc contractor and radiating member are connected to the holding cap via a swirl ring. In some embodiments, the shield insulator is press-fitted into at least one of the shield and the gas flow divertor. In some embodiments, the shield insulator is electrically insulating. In some embodiments, the shielded insulator is thermally conductive. In some embodiments, the shielded insulator comprises anodized aluminum. In some embodiments, the shield has a heat capacity to current ratio of about 2 to about 4 W / (mKA). In some embodiments, the cartridge or consumable assembly comprises a sleeve placed around a portion of the radiating member. In some embodiments, the sleeve comprises an anodized layer formed to electrically insulate the radiating member from the base of the arc shrinker. In some embodiments, the sleeve comprises a set of flow planes.

In some embodiments, the cartridge is replaced as a unit. In some embodiments, the length of the radiating element can be adjusted to match the life of the nozzle so that multiple cartridge parts reach the end of their useful life at about the same time. In some embodiments, the cutting quality may be similar to that achieved using current consumables. In some embodiments, the cartridge-type consumable assembly comprises a spring electrode located within the nozzle body and a sealing device located within the lock ring. The sealing device can be configured to connect to a plasma arc torch. The spring electrode can include a pushpin or contact element that extends into the electrode body and is connected to a spring located between the contact element and the electrode body. In some embodiments, the electrode sleeve can have a front end shaped (eg, scooped up) to direct the gas flow in the cartridge.

In one aspect, the invention features a replaceable cartridge for a plasma arc torch. The replaceable cartridge includes a cartridge body having a first section and a second section. The first and second sections are connected at boundaries to form a substantially hollow chamber. Boundaries provide a cohesive force that anchors the first and second sections together. The cartridge also includes an arc shrink member located within the second section. The cartridge also includes electrodes contained within a substantially hollow chamber. The cartridge also includes a contact initiation spring element attached to the electrode. The spring element provides a separating force that urges the electrode towards at least one of the first or second sections of the body. The separating force has a magnitude smaller than the magnitude of the binding force.

In some embodiments, the gas input moves the electrodes and overcomes the separation force. In some embodiments, the electrodes and at least a portion of the contact initiation spring element are located in a substantially hollow chamber non-removably. In some embodiments, the base of the arc shrink member is anodized. In some embodiments, the cartridge has a region having a thermal conductivity of about 200-400 watts per meter per Kelvin degree. In some embodiments, the shield has a heat capacity to current ratio of 2-4 W / (mKA). In some embodiments, the cartridge comprises a cap insert connected to a second section of the cartridge body, the cap insert substantially orients the electrode and holds the electrode within the cartridge body.

In another aspect, the invention features a sealed cartridge unit for a plasma arc torch. The cartridge unit comprises a substantially hollow frame comprising a first substantially hollow portion defining a first end and a second substantially hollow portion defining a second end. include. The cartridge unit includes an arc emitter located within the frame. The arc emitter can translate with respect to the frame. The cartridge includes an arc contractor attached to the second end of the frame. The cartridge contains an elastic element that has elasticity to physically communicate with the frame. The elastic element urges the arc emitter toward either the first end or the second end to facilitate ignition at or near the arc emitter.

In some embodiments, the gas input moves the electrodes and overcomes the separation force. In some embodiments, the frame comprises an electrical insulator. In some embodiments, the frame comprises at least one of a metal or a strong thermally conductive material. In some embodiments, the frame is anodized. In some embodiments, the cartridge comprises at least one set of flow holes, with each flow hole in the set of flow holes being offset radially from the other flow holes. In some embodiments, the flow hole has a total cross-sectional area of about 6.5 square centimeters (about 1 square inch). In some embodiments, the first end is configured to connect to the shield via a shield insulator, the shield, arc shrinker, and frame being thermally coupled. In some embodiments, the cartridge unit has a region having a thermal conductivity of about 200 to 400 watts per meter per Kelvin degree. In some embodiments, the cartridge comprises a cartridge cap located at the second end of the frame, the cartridge cap being formed to contact the arc emitter and hold the arc emitter within the frame. ..

In another aspect, the invention features a single replaceable consumable assembly for a plasma arc torch. The consumable assembly consists of a gas flow diverter, an arc contractor physically connected to the gas flow diverter, a gas flow diverter and a radiating member substantially located within the arc diverter, and a radiating member and a gas flow divertor. Alternatively, it includes an elastic arc initiator disposed between the arc contractor and at least one. At least a portion of each of the gas flow diverter, arc contractor, radiating member, and arc initiator is non-removably integrated within the consumable assembly.

In some embodiments, the radiating member comprises an electrode and the arc starter comprises a spring. In some embodiments, the gas flow diverter is anodized. In some embodiments, the gas flow diverter comprises a cap insert located substantially opposite to the arc contractor, the cap insert substantially orients the radiating member and the radiating member within the gas flow diverter. To hold. In some embodiments, the seal is placed within the cap insert. In some embodiments, the consumable assembly comprises a shield connected to a gas flow diverter. In some embodiments, the shield is connected to the gas flow diverter via a shield insulator.

In another aspect, the invention features a frame for a single replaceable consumable cartridge configured to be installed in a plasma arc torch. The frame includes a hollow body adapted to receive a translationally movable contact initiation electrode. The body has an inner surface and an outer surface. The body contains a substantially cylindrical metal core. The body also includes an electrically insulating overmolded plastic casing that at least substantially surrounds the tip of a substantially cylindrical metal core. The body also includes a set of flow paths that fluidly connect the outer surface of the hollow body and the inner surface of the hollow body. The flow path is offset to impart a swirling fluid flow pattern to the passing plasma gas. In some embodiments, the substantially cylindrical metal core is formed by stamping.

In some embodiments, the substantially cylindrical metal core is formed by stamping. In some embodiments, the substantially cylindrical metal core is made of brass. In some embodiments, the substantially cylindrical metal core comprises anodized moieties. In some embodiments, each channel in a set of channels is radially offset from the other channels. In some embodiments, the flow path has a total cross-sectional area of about 6.5 square centimeters (about 1 square inch). In some embodiments, the first end of the frame is configured to be inseparably connected to the nozzle so that the nozzle, frame, and electrodes are arranged as a single unit. In some embodiments, the first end of the frame is configured to connect to the shield via a shield insulator, the shield being thermally coupled to the frame.

In another aspect, the invention features a method of cooling a plasma arc torch. The method comprises providing a composite consumable with a frame defining a plurality of holes. Parts such as electrodes, nozzles, and shields are incorporated in the composite consumables. The holes fluidly connect the outer surface of the frame to the inner surface of the frame. The holes are offset to impart a swirling fluid flow pattern to the passing plasma gas. The method also involves installing a composite consumable on the plasma arc torch. The method also involves flowing the cooling fluid through a plurality of holes. The cooling fluid forms a fluid flow pattern that cools at least one of the electrodes, nozzles, or shields, thereby removing at least 1 watt of power from the plasma arc torch during operation. The frame is adapted to receive a translationally movable contact initiation electrode. The frame is an electrically insulating overmolded that at least substantially surrounds the tip of (i) a substantially cylindrical metal core and / or (ii) a substantially cylindrical metal core. Includes plastic casing.

In some embodiments, the substantially cylindrical metal core is formed by stamping. In some embodiments, the substantially cylindrical metal core is made of brass. In some embodiments, the substantially cylindrical metal core comprises anodized moieties. In some embodiments, each hole in the plurality of holes is radially offset from the other holes. In some embodiments, the hole has a total cross-sectional area of about 6.5 square centimeters (about 1 square inch). In some embodiments, the first end of the frame is configured to be non-removably connected to the nozzle so that the nozzle, frame, and electrodes are arranged as a single unit. In some embodiments, the first end of the frame is configured to connect to the nozzle and / or shield via a shield insulator, the shield being thermally coupled to the frame. In some embodiments, the set of channels extends into additional components that are non-removably attached to the front of the nozzle. In some embodiments, a substantially cylindrical metal core provides geometric stability, causing the electrodes to stop and not slide, and / or the nozzle to drop off, a deformation of the frame. prevent.

In another aspect, the invention features a method of making a single replaceable consumable cartridge configured to be installed in a plasma arc torch. The method comprises providing a hollow body adapted to receive a translationally movable contact initiation electrode. The body has an inner surface and an outer surface. The body contains a substantially cylindrical metal core. This method involves overmolding an electrically insulating plastic casing onto a hollow body. The electrically insulating plastic casing at least substantially surrounds the tip of the substantially cylindrical metal core. The method also comprises providing a set of flow paths that fluidly connect the outer surface of the hollow body and the inner surface of the hollow body. The flow path is offset to impart a swirling fluid flow pattern to the passing plasma gas.

The above discussion, when construed in conjunction with the accompanying drawings, will be more easily understood from the following detailed description of the invention.

FIG. 1 is a schematic cross-sectional view of a cartridge for a plasma arc cutting system according to an exemplary embodiment of the present invention. FIG. 2A is an isometric view of a single cartridge for a plasma arc cutting system according to an exemplary embodiment of the invention. FIG. 2B is a cross-sectional view of a single cartridge for a plasma arc cutting system according to an exemplary embodiment of the invention. FIG. 2C is a cross-sectional view of a single cartridge for a plasma arc cutting system according to an exemplary embodiment of the invention. FIG. 2D is a cross-sectional view of a plasma arc torch cartridge frame with an overmolded plastic casing according to an exemplary embodiment of the invention. FIG. 3A is an isometric view of an internal cartridge assembly for a plasma arc torch according to an exemplary embodiment of the invention. FIG. 3B is a cross-sectional view of an internal cartridge assembly for a plasma arc torch according to an exemplary embodiment of the invention. FIG. 4A is a cross-sectional view of a consumable cartridge for a plasma arc cutting system according to an exemplary embodiment of the invention, each cartridge having a nozzle, an electrode, a swirl ring, an elastic element, and an end cap. FIG. 4B is a cross-sectional view of a consumable cartridge for a plasma arc cutting system according to an exemplary embodiment of the invention, where each cartridge has a nozzle, electrodes, swirl rings, elastic elements, and an end cap. FIG. 5 is a cross-sectional view of a consumable cartridge for a plasma arc cutting system with nozzles, electrodes, swirl rings, elastic elements, and end caps according to an exemplary embodiment of the invention.

FIG. 1 is a schematic cross-sectional view of a cartridge 100 for a plasma arc cutting system according to an exemplary embodiment of the present invention. Cartridge 100 has substantially a first section 112A towards a first end 104, a second end 108, and a first end 104 and a second section 112B towards a second end 108. Has a hollow frame 112. The cartridge 100 also includes an arc emitter 120, an arc contractor 124, and an elastic element 128. The arc emitter 120 is arranged in the frame 112 and can be translated with respect to the frame 112. As shown, the arc contractor 124 forms part of the frame 112 (eg, at the second end 108, in some embodiments it can be attached to the frame 112). The elastic element 128 is physically connected to the frame 112, for example, directly to the first section 112A. In some embodiments, the elastic member 128 is a contact initiation spring element attached to the arc emitter 120. The elastic element 128 can be configured to carry a pilot current from the frame 112 to the arc emitter 120. The elastic element 128 may urge the arc emitter 120 towards either the first end 104 or the second end 108 to facilitate ignition in or near the arc emitter 120. The arc emitter 120 may be an electrode and may include a highly radioactive element 122 such as a hafnium insert.

The first section 112A and the second section 112B are connected at a boundary 132 to form a substantially hollow chamber. The boundary 132 provides a _coupling force that anchors the first section 112A and the second section 112B together. The elastic member 128 can provide a separating force (F _separation ) that urges the arc emitter 120 toward at least one of the first section 112A or the second section 112B. The separating force may have a magnitude smaller than the magnitude of the binding force. In some embodiments, the coupling force is bounded by at least one of the static frictional forces, adhesive forces, or normal forces (eg, forces against downward gravity) provided by the notch 136 at the boundary 132. Provided at 132. In some embodiments, the cohesive force is stronger than the force that a person can overcome by hand, either intentionally or carelessly.

In some embodiments, the frame 112 comprises at least one of a metal (eg, aluminum) or other thermally conductive material. In some embodiments, the frame 112 is formed by molding. In some embodiments, the frame 112 is anodized (eg, including aluminum anodized, as fully described below). In some embodiments, the frame 112 comprises an electrical insulator, such as aluminum anodic oxide and / or a thermoplastic (eg, PEEK, Torlon®, Vespel®, etc.). In some embodiments, at least one of the first end 104 or the second end 108 of the frame 112 comprises a threaded region formed to engage complementary parts. In some embodiments, the electrode 120 comprises an elastic element 128 such as a spring.

In some embodiments, the outer surface of the cartridge 100 is formed to connect to or fit into a holding cap or cartridge cap (not shown). In some embodiments, the retaining cap is replaceable, threaded, and / or snap-on. The cartridge cap can be placed (eg, can be surrounded) around the second end 108 of the frame 112. The cartridge cap can be formed so as to contact the arc emitter 120 and hold the arc emitter 120 within the frame 112. The cartridge cap can define the opening of the arc emitter 120. The cartridge cap can include a fluid sealing surface located around the opening of the arc emitter 120. In some embodiments, the cartridge cap substantially orients the electrode 120 and holds the electrode 120 within the cartridge 100. In some embodiments, the cartridge cap comprises a seal.

The cartridge 100 can be a "consumable" cartridge or a collection of consumable parts, for example, the cartridge 100 can be replaced as a unit after reaching the end of its useful life. The cartridge 100 can be a sealed unit that is not intended to replace individual components. In some embodiments, the individual components are non-removably located within the cartridge 100 or integrated into the cartridge 100. For example, at least a portion of the electrode 120 and the contact initiation spring element 128 can be non-removably placed within the frame 112 and, for example, can be sealed within the frame 112 and / or removed or replaced by an operator. Not intended to be. In some embodiments, the cartridge 100 is a consumable part. In some embodiments, the components (eg, frame 112 and arc contractor 124) may be connected via press fit or other similar means with tight tolerances and will deteriorate, break or fail when separated. ..

FIG. 2A is an isometric view of a single cartridge 200 for a plasma arc cutting system according to an exemplary embodiment of the invention. Visible from the outside are a plastic outer section 204, a metal outer section 208, and a copper outer section 212 (eg, a nozzle shield). The plastic outer section 204 and the metal outer section 208 are joined at a joint 206. In some embodiments, the junction 206 is included in or near the tapered region. In some embodiments, the outer section 204 of the plastic is a retaining cap. In some embodiments, the metal outer section 208 is a shielded insulator. In some embodiments, the metal outer section 208 is made of a material other than copper substantially. In some embodiments, the copper outer section 212 is made of pure or substantially pure copper or a copper alloy. The parts of the cartridge 200 are shown in more detail in FIG. 2B described below.

FIG. 2B is a cross-sectional view of a single cartridge 200 for a plasma arc cutting system according to an exemplary embodiment of the invention. In this figure, a nozzle body 216, a nozzle orifice 218, an electrode 220 having a radiating element 222, an insulator sleeve 224 having an elongated portion 224A, an elastic element 226, and an electrode contact button 236 (eg, made of brass). Additional elements of the cartridge 200 are shown, including. In the present invention, one or more of these elements can be redesigned to achieve one or more of the above objects.

For example, the nozzle body 216 can be formed from a conductive material (eg, a highly conductive material such as aluminum) and can be attached to other parts of the cartridge 200 (eg, in direct physical contact). can). In some embodiments, the nozzle body 216 is in thermal communication with a particular part of the cartridge 200 (eg, via heat conduction), but is electrically isolated from the other parts. For example, the nozzle body 216 can function as a heat sink for the nozzle orifice 218 while remaining electrically isolated from the nozzle shield 212. Such configurations can enhance cooling performance (eg, nozzles and electrodes) and reduce manufacturing costs compared to previously used materials (eg, Vespel®). In some embodiments, the cartridge has a region having a thermal conductivity of about 200-400 watts per meter per Kelvin degree (eg, aluminum has a thermal conductivity of 200-250 W / (mK)). Whereas copper can have a thermal conductivity of 350-400 W / (m · K)). In some embodiments, the consumable cartridge has a heat capacity to current ratio of 2-4 W / (mKA).

Further, the nozzle body 216 includes a set of inlet swirl holes 228 (eg, swirl holes 228A and 228B). In some embodiments, the set of inlet swirl holes 228 comprises 5 swirl holes, or optionally between 3 and 10. The swirl hole 228 is offset radially to provide a swirl flow (eg, radial and tangential velocity components) to the gas flowing through the swirl hole 228 (eg, shield gas, plasma gas, and / or plenum gas). be able to. In this configuration, the nozzle body 216 eliminates the need for a conventional swirl ring in order to provide the swirl functionality previously provided by the swirl ring. Further, in some embodiments, the nozzle body 216 is formed via a forming process, eliminating the need for expensive and time-consuming drilling procedures for forming swirl holes. In some embodiments, the nozzle shield 212 includes an angle 232 that encourages the flow of fluid away from the plasma arc during operation.

FIG. 2C is a cross-sectional view of a single cartridge 240 for a plasma arc cutting system according to an exemplary embodiment of the invention. The single cartridge 240 may be similar in many respects to the cartridge 200 shown in FIG. 2B, but may differ in certain other respects. For example, the cartridge 240 utilizes a punched torch interface 250 (eg, punched copper pieces) having a "T" cross section. The interface 250 allows the electrodes to slide more freely than in the FIG. 2B configuration, which uses electrodes with a nipple function to form an engagement surface with the spring. In FIG. 2C, the cap and nozzle body are open for ease of manufacture and for the electrodes to freely slide into the nozzle body during assembly of the cartridge. The spring can then be placed on the electrode and the punched torch interface 250 can easily snap to the nozzle body and secure the electrode in it using the small tab feature 252. .. Such a configuration avoids the need to press in multiple parts together (and then avoids the need to achieve tight tolerances between the parts) and / or different parts of the torch in different directions. Avoid the need to assemble from. Using the cartridge 240, the manufacturer can simply slide the electrode into place in one step.

Further, the cartridge 240 achieves a swirl function by using a molded slotted swirl feature 266 instead of using a hole drilled in the nozzle body. In this configuration, during operation, the gas flows from slot 266 into the plasma chamber, forming a swirl gas around the plasma arc. Also, during operation, the gas can flow through the molded gas shield channel 254 to further cool the nozzle body. The slot 266 forms a set of swirl holes when the nozzle body, nozzle orifice, and / or nozzle liner are connected. The gas supplied to the slot is carried from the torch through a chamber formed by the inner surface of the nozzle body and the outer surface of the nozzle liner (combined to form a swirl hole). Such a configuration eliminates the need for post-processing machining steps and associated costs. Further, the cartridge 240 includes a radial swage connection 258 between the nozzle orifice and the nozzle body. The radial swage connection 258 provides a robust connection interface that allows maintenance of contact between the nozzle orifice and the nozzle body, but also exposes a significant surface area for the heat transferred from the nozzle orifice to the nozzle body. .. Finally, in this embodiment, the electrode sleeve is removed and replaced with a more traditional heat exchanger.

FIG. 2D is a cross-sectional view of a plasma arc torch cartridge frame 280 with an overmolded plastic casing 282 according to an exemplary embodiment of the invention. The frame 280 includes a hollow body 284 adapted to receive a translationally movable contact initiation electrode. The body 284 has an inner surface 286 and an outer surface 288. The body 284 contains a substantially cylindrical metal core 290 that can be formed by stamping. Also, the body 284 is an electrically insulating overmolded plastic (thermosetting or thermoplastic) casing that at least substantially surrounds the tip of the substantially cylindrical metal core 290. Includes 282. In some embodiments, the body 284 comprises a set of flow paths 292 that fluidly connect the outer surface 288 and the inner surface 286 (eg, at the tip of the cartridge frame 280 as shown). The flow path 292 may be offset to impart a swirling fluid flow pattern to the passing plasma gas. In one embodiment, the hole imparts a swirling flow to the plasma gas that enters the plasma chamber and enters the cartridge, some of the plasma moves towards the tip to generate a plasma arc, and some of the gas is on the proximal side. To cool the electrodes. The flow path 292 can be formed entirely within the plastic, for example by molding, and can be crimped to another cartridge or torch component, such as the base end of a nozzle or shield (not shown). The crimped component may form part of the swirl flow path 292.

In some embodiments, the cylindrical metal core 290 helps to overcome certain thermal cycle and overheating problems due to the use of molded plastic in the swirl ring. For example, the plastics used in this context can exhibit local melting of the inner diameter, for example when the electrode is near the end of its life. At this point, the temperature of the electrodes can be higher than the melting point of the plastic used, causing the plastic to melt and deform. Under these circumstances, the electrodes can be prevented from moving freely within the swirl ring. In extreme cases, this malfunction can damage the torch (if the arc can be started but the electrodes cannot move). In other failure modes, the nozzle may separate from the frame. As a solution, the thermoplastic can be overmolded into stamped brass to provide geometric stability without the aforementioned melting and warping. The material of the sleeve can be a metal alloy and can be used with or without a second metal coating. In some embodiments, brass is used. Other metals that can be used include nickel-plated brass, copper, aluminum, steel, or other metals. Another advantage of plastic overmolded into a brass sleeve is that it can reduce costs (for example, $ 1.30 compared to about $ 5 for Vespel®). Such embodiments can reduce or eliminate local melting of the inner diameter, providing reliable starting performance and a sturdy torch.

FIG. 3A is an isometric view of the internal cartridge assembly 300 for a plasma arc torch according to an exemplary embodiment of the invention. What is visible from the outside is a shield 304 with vent holes 306 (eg, holes 306A-306D as shown in FIG. 3A), flow holes or inlet swivel holes 312 (eg, holes 312A, 312B as shown in FIG. 3A). ) The nozzle body 308, the front insulator (or shield insulator) 314, and the rear insulator (or lock ring) 316. These elements and additional elements are described more fully in conjunction with the cross-sectional views shown in FIG. 3B below.

FIG. 3B is a cross-sectional view of the internal cartridge assembly 300 of FIG. 3A according to an exemplary embodiment of the invention. In this figure, some additional parts of the internal cartridge assembly 300 are shown, which are the electrodes 320 with the radiating element 322, the arc contractor, ie the nozzle orifice 324, the shield directed to the nozzle orifice 324. It includes a flow hole 328 (eg, flow holes 328A to 328B), an insulator sleeve 332, and a cooling gas flow path 336. In this embodiment, the nozzle body 308 functions as a cartridge frame to which other components are attached.

Many features of the internal cartridge assembly 300 can enhance its cooling capacity. First, the nozzle body 308 can be made of aluminum, which can enhance heat conduction over conventional materials and configurations as described above. Second, the nozzle orifice 324 can be made of copper and can be pressed against the nozzle body 308. In such an embodiment, the nozzle body 308 can function as a heat sink for the copper nozzle orifice 324. Third, the improved gas flow surface can be assisted in cooling, for example with a shielded gas flowing forward through holes 328A, 328B just outside the press area. Also, the press-fitting arrangement can provide an improved heat transfer path between the torch components as a result of tight tolerances between the surfaces of the components. In some embodiments, the press-fitting arrangement comprises a tight fit and / or a tabbed or interlocking fit with one or more stepped features. In addition, the small size of the press-fit design has the added benefit of reducing manufacturing and / or material costs and simplifying the manufacture and assembly of parts (eg, by reducing the number of parts).

Also, the nozzle shield 304 can be made of copper and can be pressed against the anodized aluminum insulator 314 at the surface 305A. The assembly can then be pressed against the nozzle body 308 at the press fit surface 305B. In such an embodiment, the shield insulator 314 connects the nozzle body 308 to the shield 304. In some embodiments, the shield insulator 314 is press-fitted into the nozzle body 308. In some embodiments, the shield insulator 314 is an electrically insulating ring and / or includes a set of press-fit surfaces 305A, 305B connecting the shield 304 and the nozzle body 308. The shield insulator 314 can connect the nozzle body 308 to the shield 304 so that the nozzle body 308 and the shield 304 are electrically isolated from each other while transmitting thermal energy to each other. In some embodiments, the use of two-piece shielded insulators can increase the electrical insulation capacity (eg, double) as a result of the increased contact surface.

The nozzle shield 304 can be significantly smaller than a conventional shield, allowing for efficient manufacturing and assembly of parts, improved durability, and greater assurance of proper orientation of cartridge parts with respect to each other. As an example, for a 45 amp system, a prior art stock shield can have a diameter of about 2.54 centimeters (about 1 inch) and a mass of about 18.1 grams (about 0.04 pounds). Cartridge shields according to the invention have a diameter of about 1.27 centimeters (about 0.5 inches) and less than 4.5 grams (less than 0.01 pounds) (eg, about 3.2 grams (about 0.007 pounds)). ) May have a mass. For a 105 amp system, prior art stock shields can have a diameter of about 2.54 centimeters (about 1 inch) and a mass of about 22.3 grams (about 0.05 pounds), according to the invention. The cartridge shield has a diameter of about 1.27 centimeters and a mass of about 4.5 grams (eg, about 5.9 grams). May have.

The small size configuration has great advantages. First, because the mass-reduced component has a reduced heat capacity, the component is rapidly cooled during postflow and / or more heat is transferred to the cooling gas during operation. Second, the smaller the shield, the higher the temperature can reach during operation and the more heat can be transferred to the cooling gas. In some embodiments, the nozzle shield 304 is exposed to cold gas entering the shield region, for example, through the shield flow hole 328, which can further reduce the temperature. Each flow hole 328 may have a total cross-sectional area of at least about 6.5 square centimeters (about 1 square inch).

In some embodiments, the electrode 320 comprises a copper base. In some embodiments, the base of the electrode 320 has a small diameter with an pressed insulator sleeve 332 made of anodized aluminum and / or plastic used for electrical insulation. In some embodiments, a cooling gas flow path or gap 336 is present between the insulator sleeve 332 and the nozzle body 308. In some embodiments, the cooling gas flows through the gap 336. In some embodiments, a "dumbbell" configuration 340 defined by two end contacts 340A, 340B is used, which reduces or minimizes the contact area between the nozzle body 308 and the insulator sleeve 332. can do. With such a configuration, friction between parts can be reduced.

In some embodiments, the sleeve 332 contacts the electrode 320, which may be part of a separate current path from the nozzle body 308 and / or a different part of the current path from the nozzle body 308. In some embodiments, the electrode 320 and the nozzle body 308 may be electrically separated by a gap to generate an arc and / or to ensure proper orientation of the components within the torch. In such an embodiment, the nozzle 308 and the electrode 320 may be in physical contact between the sleeve 332 and the nozzle body 308. In such an embodiment, an insulating layer is required in this region so that the current can pass through the radiating element 322.

In some embodiments, the wall of the nozzle body 342 in which the electrode 320 moves close to it is compared during operation when the gas flow passes directly both inside the nozzle body 308 and on the outer surface 344 of the nozzle 324. It can stay at a low temperature. The choice of material for the design of the nozzle body 342 (eg, aluminum or other metal) provides better conduction paths and heat dissipation performance compared to conventional materials such as Vespel®. Such factors assist in cooling the electrode insulating component and allow the electrode to function even after deep pits have been formed in the radiating element by the use of the electrode.

In some embodiments, the lock ring 316 (or separation ring) forms an interface 346 between the cartridge 300 and the torch. In some embodiments, the lock ring 316 may be made of anodized aluminum. The lock ring 316 can be pushed into the nozzle body to "trap" the movable electrode 320. The lock ring 316 can accommodate the components in the cartridge 300 and electrically insulate the torch. In some embodiments, the lock ring 316 is replaced by heat shrinkage or adhesion. In some embodiments, the lock ring 316 orients the cartridge 300 (eg, axially), optimizes gas flow, allows electrical connection to the cathode, and / or provides electrical insulation. Is formed like this.

In the various embodiments described herein, the cartridge or consumable assembly is approximately 8.9 centimeters (approximately 3.5 inches) long and 2.8 centimeters (1.1 inches) in diameter. be. In some embodiments, the retaining cap is considered, for example, as part of the torch rather than a consumable part. Such a configuration eliminates the need for post-assembly machining (compared to some torch assemblies that require the final machining step to achieve the functional axiality of the cartridge) and the machine. The machining step can be minimized. In some embodiments, the reduction of swirl holes can minimize drilling operations as compared to prior art swirl rings. In some embodiments, replacing Vespel® with aluminum can significantly reduce the cost of manufacturing the cartridge. In some embodiments, copper is used only in specific locations within electrodes, nozzles, and / or orifices, and manufacturing costs can be reduced by reducing the use of this expensive material. For example, copper can be concentrated primarily in the inner core or region. Copper may be desirable due to its thermal and electrical properties, but it is more expensive than other materials, so a design that minimizes its use is sought.

4A, 4B and 5 are cross-sectional views of consumable cartridges for a plasma arc cutting system according to an exemplary embodiment of the invention, where each cartridge has a nozzle, electrodes, swirl rings, elastic elements, and ends. Has a cap. FIG. 4A shows an exemplary cartridge design 400. As shown, the cartridge 400 includes a swirl ring 402, an end cap 406, a nozzle 408, and an electrode 404. The electrode 404 can be a spring anterior electrode for the contact initiation plasma arc torch. Here, the elastic element 412 (for example, a spring) applies a separating force to the tip of the electrode 404 to urge the electrode 404 toward the cap 406 and the nozzle 408 so as to move away from the end. The elastic element 412 can also be part of the cartridge 400. The cartridge 400 may include a starting mechanism for contact to start the plasma arc torch during assembly into the torch.

The swirl ring 402 can substantially extend along the longitudinal axis 410 of the electrode 404 over the length of the electrode 404. In some embodiments, the swirl ring 402 is manufactured by injection molding of a high temperature thermoplastic (eg, PAI, PEI, PTFE, PEEK, PEKPEKK, etc.). Manufacturing swirl rings using thermoplastics can reduce the cost of cartridges compared to Vespel®, a relatively expensive material that has been used to manufacture swirl rings. Thermoplastics are known to have a lower operating temperature than Vespel® (thermosetting resin) and can affect swirl ring completeness and electrode life. However, the cartridge design of the present technology provides various reinforced additives that provide the desired thermal resistance and / or thermal conductivity (eg, glass fiber, minerals, boron nitride (BN), and / or cubic boron nitride). A swirl ring made from a thermoplastic resin having can be incorporated. The cartridge design of this technology solves the problem of high temperature performance and allows the effective use of thermoplastics in these cartridges. This is because (1) the thermoplastic has sufficient heat resistance and (2) the cartridge design with proper incorporation of the thermoplastic prevents the thermoplastic from being exposed to excessive temperature during operation. Because it can be done. Moreover, if the electrodes experience end-of-life events (which are also the life of the cartridge), simultaneous melting of the plastic material is not an issue.

The end cap 406 can be made of a conductive material such as copper. The end cap 406 can be inexpensively formed via stamping from a material blank and can be non-removably inserted, press fit or overmolded onto the cartridge 400. The end cap 406 includes an elastic element 412 in the cartridge 400 so that the elastic element 412 applies a separating force to the tip of the electrode 404 to urge the electrode 404 toward the nozzle 408. The 406 is configured to compress the elastic element 412 against the tip of the electrode 404. In some embodiments, the end cap 406 may be formed to fit and engage with a patterned torch head and / or may include a set of fluid flow holes formed through it.

In some embodiments, a non-releaseable snap-fit interface 414 is formed between the swirl ring 402 and the nozzle 408 to connect the two consumable parts together as part of the cartridge 400. In addition, a second snap-fit interface 416 can be formed between the swirl ring 402 and the end cap 406 to connect the two consumable parts together as part of the cartridge 400. Other manufacturing and assembly options are available and feasible. For example, the swirl ring 402 can be overmolded onto the end cap 406. Also, the end cap 406 can be encapsulated by a swirl ring 402 and an elastic element 412 (eg, a spring), and the end cap 406 can be moved within the cartridge 400.

FIG. 4B shows another exemplary cartridge design 450. As shown, the cartridge 450 includes a swirl ring 452, an end cap 456, a nozzle 458, and an electrode 454. In some embodiments, the cartridge 450 comprises an elastic element 462 that functions similarly to the elastic element 412 of FIG. 4A. The cartridges of FIGS. 4A and 4B have different electrodes (eg, heat exchanger flanges of different sizes, circumferential flanges for uniform flow), different nozzles (eg, different swirl ring attachments), and different swirl rings (eg, different swirl rings). Has different swirl holes and attachments). In the cartridge design 450 of FIG. 4B, the interface 464 is formed when the swirl ring 452 is inserted in place with respect to the nozzle 458. Another interface 466 may be formed between the swirl ring 452 and the end cap 456.

FIG. 5 shows another exemplary cartridge design 500. As shown, the cartridge 500 includes a swirl ring 502, a sleeve 514, an end cap 506, a nozzle 508, and an electrode 504. In some embodiments, the cartridge 500 comprises an elastic element 512 that functions similarly to the elastic element 512 of FIG. 4A. The sleeve 514 and / or the end cap 506 can be made from a conductive material (eg, copper) using a stamping method. The sleeve 514 can be press fit or overmolded into the cartridge 500. The end cap 506 can be part of the sleeve 514. Therefore, the sleeve 514 and the end cap 506 can be configured as a single component.

As shown, the swirl ring 502 can be relatively short compared to the swirl ring 402 so that the swirl ring 502 extends only along a portion of the length of the electrode 504 at the longitudinal axis 510. .. Like the swirl ring 402, the swirl ring 502 can be manufactured by injection molding of a high temperature thermoplastic (eg, Torlon®). A snap-fit interface 520 can be formed between the swirl ring 502 and the nozzle 508 to connect the two consumable parts together as part of the cartridge 500. Another snap-fit interface 518 can be formed between the swirl ring 502 and the sleeve 514 to connect the two consumable parts together as part of the cartridge 500. Alternatively, the swirl ring 502 can be overmolded onto the sleeve 514.

There are many advantages associated with using cartridges in plasma arc torches. First, such a design improves usability through rapid change capabilities, short setup times, and end-user consumable selection. In addition, since a series of consumables are replaced at once when the cartridge is replaced, consistent cutting performance can be obtained. In contrast, performance fluctuations occur when multiple parts are individually modified at different times. For example, long-term reuse of the same swirl ring can change dimensions with each blowout, so regular replacement of all other parts will change the quality of performance. In addition, the cost of manufacturing and / or installing the cartridge is lower than the total cost of the consumable set, so the cost of changing the cartridge is lower than the cost of changing the consumable set. In addition, various cartridges can be designed to optimize torch operation for various applications such as marking, cutting and maintaining long life.

Although the invention has been specifically shown and described with reference to certain preferred embodiments, those skilled in the art will not deviate from the spirit and scope of the invention as defined by the following claims. It should be understood that various changes in form and detail can be made within.

Claims (16)

A frame for a single replaceable consumable cartridge configured to be installed on a plasma arc torch.
It comprises a hollow body adapted to receive a translationally movable contact initiation electrode, the body having an inner surface and an outer surface, which body is:
With a substantially cylindrical metal core,
An electrically insulating overmolded plastic casing that at least substantially surrounds the tip of the substantially cylindrical metal core.
It has a set of flow paths that fluidly connect the outer surface of the hollow body and the inner surface of the hollow body, and the flow paths are offset to impart a swirling fluid flow pattern to the passing plasma gas. The frame that has been. The frame of claim 1, wherein the substantially cylindrical metal core is formed by stamping. The frame of claim 1, wherein the substantially cylindrical metal core is made of brass. The frame of claim 1, wherein the substantially cylindrical metal core comprises an anodized portion. The frame according to claim 1, wherein each flow path in the set of flow paths is offset in the radial direction from the other flow paths. The frame of claim 1, wherein the flow path has a total cross-sectional area of about 6.5 square centimeters. The frame according to claim 1, wherein the first end of the frame is configured to connect to a nozzle. 7. The frame of claim 7, wherein the set of channels extends into an additional component that is non-removably attached to the front of the nozzle. A method of cooling a plasma arc torch,
To provide a composite consumable with a frame defining a plurality of holes, the composite consumable has an integrated component including electrodes, nozzles and shields, wherein the holes are the outer surface of the frame and said. Fluidly connected to the inner surface of the frame, the holes are offset to impart a swirling fluid flow pattern to the passing plasma gas, providing.
Installing the compound consumables on the plasma arc torch and
A cooling fluid forming a fluid flow pattern that cools at least one of the electrode, the nozzle, or the shield is flowed through the plurality of holes.
The frame is adapted to receive a collimable contact initiation electrode and is (i) around a substantially cylindrical metal core and (ii) around the tip of the substantially cylindrical metal core. A method that includes an electrically insulating overmolded plastic casing that surrounds at least substantially. 9. The method of claim 9, wherein the substantially cylindrical metal core is formed by stamping. 9. The method of claim 9, wherein the substantially cylindrical metal core is made of brass. 9. The method of claim 9, wherein the substantially cylindrical metal core comprises an anodized portion. The method of claim 9, wherein each of the plurality of holes is offset radially from the other holes. The method of claim 9, wherein the hole has a total cross-sectional area of about 6.5 square centimeters. 9. The method of claim 9, wherein the first end of the frame is configured to connect to the shield via a shield insulator, the shield being thermally coupled to the frame. A method of manufacturing a single replaceable consumable cartridge configured to be installed in a plasma arc torch.
To provide a hollow body adapted to receive a translationally movable contact initiation electrode, the body having an inner surface and an outer surface, the body comprising a substantially cylindrical metal core. To provide and
By overmolding an electrically insulating plastic casing, the electrically insulating plastic casing at least substantially surrounds the tip of the substantially cylindrical metal core. To do and
To provide a set of flow paths that fluidly connect the outer surface of the hollow body to the inner surface of the hollow body, the flow path imparting a swirling fluid flow pattern to the passing plasma gas. How to provide and provide, which is offset so that.

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