Patent Application
20250065428
This disclosure relates generally to machining and, more particularly, to electrical discharge machining a workpiece.
A gas turbine engine includes various fluid cooled components such as turbine blades and turbine vanes. Such fluid cooled components may include one or more cooling apertures extending through a sidewall of the respective component. Various methods are known in the art for forming cooling apertures, including methods for electrical discharge machining the cooling apertures. While these known cooling aperture formation methods have various benefits, there is still room in the art form improvement.
According to an aspect of the present disclosure, a manufacturing method is provided during which a workpiece is electrical discharge machined using an electrode to form an aperture in the workpiece. A first voltage is measured indicative of a gap voltage between the electrode and the workpiece using a first measurement device to provide a first measurement signal indicative of the first voltage. Movement of the electrode is controlled using the first measurement signal. A second voltage is measured indicative of the gap voltage using a second measurement device to provide a second measurement signal indicative of the second voltage. A determination is made whether the electrode has broken through the workpiece using the second measurement signal.
According to another aspect of the present disclosure, another manufacturing method is provided during which a workpiece is electrical discharge machined using an electrode to form an aperture in the workpiece. The workpiece extends between a face surface and a back surface. The electrical discharge machining includes plunging the electrode into the workpiece through the face surface. An EDM voltage is measured indicative of a gap voltage between the electrode and the workpiece using a high frequency measurement device to provide an EDM voltage measurement signal indicative of the EDM voltage. The EDM voltage is measured by the high frequency measurement device at a measurement frequency equal to or greater than ten kilohertz. A determination is made whether the electrode has broken through the back surface using the EDM voltage measurement signal.
According to still another aspect of the present disclosure, another manufacturing method is provided during which a workpiece is electrical discharge machined using an electrode to form an aperture in the workpiece. The workpiece extends between a face surface and a back surface. The workpiece is secured to a support by a fixture. The electrical discharge machining includes plunging the electrode into the workpiece through the face surface. The electrode is supported by and electrically coupled to a guide. A measurement voltage is measured between the guide and the fixture indicative of a gap voltage between the electrode and the workpiece using a measurement device to provide a measurement signal indicative of the measurement voltage. The measurement device is electrically coupled to the guide and the fixture. A determination is made whether the electrode has broken through the back surface using the measurement signal.
The manufacturing method may also include: measuring an EDM system voltage indicative of the gap voltage using a low frequency measurement device to provide an EDM system voltage measurement signal indicative of the gap voltage, wherein the EDM system voltage may be measured by the low frequency measurement device at a measurement frequency equal to or less than five-hundred hertz; and controlling movement of the electrode using the EDM system measurement signal.
The determining of whether the electrode has broken through the back surface may be performed during the electrical discharge machining. The electrical discharge machining may be terminated when it is determined that the electrode has completely broken through the back surface.
The first voltage may be measured using the first measurement device at a measurement frequency equal to or less than five-hundred hertz.
The workpiece may be secured to a support by a fixture. A first line may electrically couple a power source to the electrode. A second line may electrically couple the power source to the support. The first measurement device may be electrically coupled to the first line and the second line. The first voltage may be measured between the first line and the second line.
The second voltage may be measured using the second measurement device at a measurement frequency equal to or greater than ten kilohertz.
The electrical discharge machining may use an electrical current with a pulse width equal to or less than twenty microseconds.
The workpiece may be secured to a support by a fixture. The electrode may be supported by a guide. The second measurement device may be electrically coupled to the fixture and the guide. The second voltage may be measured between the fixture and the guide.
A first line may electrically couple a power source to the guide. A second line may electrically couple the power source to the support.
The workpiece may extend between a face surface and a back surface. The electrical discharge machining may include plunging the electrode into the workpiece through the face surface towards the back surface. The electrode may be angularly offset from the back surface by an acute angle.
The manufacturing method may also include detecting an initial breakthrough of a corner of the electrode through the back surface using the second measurement signal.
The manufacturing method may also include detecting a complete breakthrough of a tip of the electrode through the back surface using the second measurement signal.
The determining of whether the electrode has broken through the workpiece may be performed during the electrical discharge machining. The electrical discharge machining may be terminated when it is determined that the electrode has broken through the workpiece.
The determining of whether the electrode has broken through the workpiece may be performed after the electrical discharge machining. The electrical discharge machining may be repeated when it is determined that the electrode did not break through the workpiece.
The manufacturing method may also include comparing breakthrough information obtained using the second measurement signal to breakthrough information obtained using another breakthrough determination method.
The workpiece may be configured as or otherwise include a turbine engine airfoil.
The manufacturing method may also include forming a component of a turbine engine. The forming of the component may include the electrical discharge machining of the workpiece to form the aperture. A cooling hole in the component may be configured from or otherwise include the aperture.
The cooling hole may include a meter section and a diffuser section. The aperture may form at least the meter section.
The present disclosure may include any one or more of the individual features disclosed above and/or below alone or in any combination thereof.
The foregoing features and the operation of the invention will become more apparent in light of the following description and the accompanying drawings.
The present disclosure includes methods for manufacturing a component such as a fluid cooled component of a gas turbine engine. The term “manufacturing” may describe a process for original manufacturing the component; e.g., creating a brand new component. The term “manufacturing” may also or alternatively describe a process for remanufacturing or otherwise repairing the component; e.g., restoring one or more features of a previously formed component to brand new condition, similar to brand new condition, better than brand new condition, etc. The component, for example, may be repaired to fix one or more defects (e.g., cracks, wear and/or other damage) imparted during previous use of the component. The component may also or alternatively be repaired to fix one or more defects imparted during the initial formation of the component.
For ease of description, the turbine engine may be described below as a turbofan turbine engine. The present disclosure, however, is not limited to such an exemplary gas turbine engine. The turbine engine, for example, may alternatively be configured as a turbojet turbine engine, a turboprop turbine engine, a turboshaft turbine engine, a propfan turbine engine, a pusher fan turbine engine or an auxiliary power unit (APU) turbine engine. The turbine engine may be configured as a geared turbine engine or a direct drive turbine engine. The present disclosure is also not limited to aircraft applications. The turbine engine, for example, may alternatively be configured as a ground-based industrial turbine engine for power generation, or any other type of turbine engine which utilizes fluid cooled components.
The engine sections 28-31B of
Each of the engine sections 28, 29A, 29B, 31A and 31B includes a respective bladed rotor 40-44. Each of these bladed rotors 40-44 includes a plurality of rotor blades arranged circumferentially around and connected to one or more respective rotor disks. The rotor blades, for example, may be formed integral with or mechanically fastened, welded, brazed and/or otherwise attached to the respective rotor disk(s).
The fan rotor 40 is connected to a geartrain 46, for example, through a fan shaft 48. The geartrain 46 and the LPC rotor 41 are connected to and driven by the LPT rotor 44 through a low speed shaft 49. The HPC rotor 42 is connected to and driven by the HPT rotor 43 through a high speed shaft 50. The engine shafts 48-50 are rotatably supported by a plurality of bearings 52; e.g., rolling element and/or thrust bearings. Each of these bearings 52 is connected to the engine housing 34 by at least one stationary structure such as, for example, an annular support frame.
During operation, air enters the turbine engine 20 through the airflow inlet 24. This air is directed through the fan section 28 and into a core flowpath 54 and a bypass flowpath 56. The core flowpath 54 extends sequentially through the engine sections 29A-32; e.g., the engine core. The air within the core flowpath 54 may be referred to as “core air”. The bypass flowpath 56 extends through a bypass duct, which bypasses the engine core. The air within the bypass flowpath 56 may be referred to as “bypass air”.
The core air is compressed by the LPC rotor 41 and the HPC rotor 42 and directed into a combustion chamber 58 of a combustor in the combustor section 30. Fuel is injected into the combustion chamber 58 and mixed with the compressed core air to provide a fuel-air mixture. This fuel air mixture is ignited and combustion products thereof flow through and sequentially cause the HPT rotor 43 and the LPT rotor 44 to rotate. The rotation of the HPT rotor 43 and the LPT rotor 44 respectively drive rotation of the HPC rotor 42 and the LPC rotor 41 and, thus, compression of the air received from a core airflow inlet. The rotation of the LPT rotor 44 also drives rotation of the fan rotor 40, which propels the bypass air through and out of the bypass flowpath 56. The propulsion of the bypass air may account for a majority of thrust generated by the turbine engine 20; e.g., more than seventy-five percent (75%) of engine thrust. The turbine engine 20 of the present disclosure, however, is not limited to the foregoing exemplary thrust ratio.
The turbine engine 20 includes a plurality of fluid cooled components (e.g., 60A-H; generally referred to as “60”) arranged within, for example, the combustor section 30, the turbine section 31 and/or the exhaust section 32. Examples of these fluid cooled components 60 include airfoils such as, but not limited to, a rotor blade airfoil (e.g., 60A, 60D) and a stator vane airfoil (e.g., 60B, 60C, 60H). Other examples of the fluid cooled components 60 include flowpath walls such as, but not limited to, a combustor liner (e.g., 60F), an exhaust duct liner (e.g., 60E), a shroud or other flowpath wall (e.g., 60G), a rotor blade platform, a stator vane platform, and the like. Of course, various other fluid cooled components may be included in the turbine engine 20, and the present disclosure is not limited to any particular types or configurations thereof.
Referring to
The component wall 62 of
The component substrate 74 at least partially or completely forms and carries the component first surface 68. The component substrate 74 has a thickness 82 that extends vertically (e.g., along the z-axis) between and to the component first surface 68 and a second surface 84 of the component substrate 74. The substrate second surface 84 may be configured as an exterior surface of the component substrate 74 prior to being (e.g., partially or completely) covered by the coating system 76 and its one or more component coatings 78 and 80. The substrate thickness 82 may be greater than one-half (½) of the wall thickness 66. The substrate thickness 82, for example, may be between two-third (⅔) and four-fifths (⅘) of the wall thickness 66. In other embodiments, however, it is contemplated the substrate thickness 82 may be greater than four-fifths (⅘) of the wall thickness 66 or less than one-half (½) of the wall thickness 66.
The component substrate 74 is constructed from substrate material. This substrate material may be an electrically conductive material. The substrate material, for example, may be or otherwise include metal. Examples of the metal include, but are not limited to, nickel (Ni), titanium (Ti), aluminum (Al), chromium (Cr), cobalt (Co), and alloys thereof. The metal, for example, may be a nickel or cobalt based superalloy such as, but not limited to, PWA 1484 or PWA 1429.
The inner coating 78 may be configured as a bond coating between the component substrate 74 and the outer coating 80. The inner coating 78 of
The inner coating 78 is constructed from inner coating material. This inner coating material may be an electrically conductive material. The inner coating material, for example, may be or otherwise include metal. Examples of the metal include, but are not limited to, MCrAlY and MAlCrX, where “M” is nickel (Ni), cobalt (Co), iron (Fe) or any combination thereof, and where “Y” or “X” is hafnium (Hf), yttrium (Y), silicon (Si) or any combination thereof. The MCrAlY and MAlCrX may be further modified with strengthening elements such as, but not limited to, tantalum (Ta), rhenium (Re), tungsten (W), molybdenum (Mo) or any combination thereof. An example of the MCrAlY is PWA 286.
The inner coating 78 may be formed from a single layer of the inner coating material. The inner coating 78 may alternatively be formed from a plurality of layers of the inner coating material, where the inner coating material within each of those inner coating layers may be the same as one another or different from one another.
The outer coating 80 may be configured as a protective coating for the component substrate 74 and, more generally, the fluid cooled component 60. The outer coating 80, for example, may be configured as a thermal barrier layer and/or an environmental layer. The outer coating 80 at least partially or completely forms and carries the component second surface 70. The outer coating 80 of
The outer coating 80 is constructed from outer coating material. This outer coating material may be a non-electrically conductive material. The outer coating material, for example, may be or otherwise include ceramic. Examples of the ceramic include, but are not limited to, yttria stabilized zirconia (YSZ) and gadolinium zirconate (GdZ). The outer coating material of the present disclosure, however, is not limited to non-electrically conductive materials. In other embodiments, for example, the outer coating material may be an electrically conductive material; e.g., metal.
The outer coating 80 may be formed from a single layer of the outer coating material. The outer coating 80 may alternatively be formed from a plurality of layers of the outer coating material, where the outer coating material within each of those outer coating layers may be the same as one another or different from one another. For example, the outer coating 80 may include a thin interior layer of the YSZ and a thicker exterior later of the GdZ.
Each of the cooling apertures 64 extends along a longitudinal centerline 92 of the respective cooling aperture 64 between and to an inlet 94 into the respective cooling aperture 64 and an outlet 96 from the respective cooling aperture 64. This aperture centerline 92 may have a straight line geometry (e.g., in the x-y plane, in an x-z plane and/or in a y-z plane) from the cooling aperture inlet 94, through the component wall 62, to the cooling aperture outlet 96. The aperture centerline 92 of
The cooling aperture inlet 94 of
The cooling aperture outlet 96 of
The outlet geometry may be exactly or substantially the same as the inlet geometry. For example, the shape of the cooling aperture outlet 96 may be exactly or substantially the same as the shape of the cooling aperture inlet 94. Dimensions (e.g., a width) of the cooling aperture outlet 96 may also be exactly or substantially equal to dimensions (e.g., a width) of the cooling aperture inlet 94. Alternatively, referring to
Referring to
The EDM system 108 includes an electrical discharge machining (EDM) electrode 120, an electrode guide 122, an electrode actuator 124 (e.g., an electric servo motor) and an electrical power source 126 (e.g., a generator, a battery, an amplifier, the electrical grid, etc.). The electrode guide 122 is configured to support the EDM electrode 120 during electrical discharge machining. The electrode guide 122 is also electrically coupled to the EDM electrode 120. The electrode actuator 124 is configured to move (e.g., translate) the EDM electrode 120 through the electrode guide 122 and along a centerline 128 of the EDM electrode 120 (e.g., see
The EDM system 108 of
The EDM system 108 may be configured for high speed electrical discharge machining (HSEDM), hollow spindle electrical discharge machining (HSEDM), or sinker electrical discharge machining. The EDM system 108 may include a single EDM electrode 120, or multiple EDM electrodes 120 for forming multiple features (e.g., apertures) simultaneously as discussed below in further detail. The present disclosure, however, is not limited to such exemplary electrical discharge machining processes or electrode arrangements.
The monitoring system 110 includes a breakthrough monitoring voltage measurement device 144 (“breakthrough measurement device”); e.g., a high frequency measurement device, a high speed oscilloscope, etc. A first terminal 146 (e.g., a positive terminal) of the breakthrough measurement device 144 is electrically coupled to the electrode guide 122, for example independent of the first line 132. A second terminal 148 (e.g., a negative terminal) of the breakthrough measurement device 144 is electrically coupled to the workpiece fixture 116 (or the workpiece support 114), for example independent of the second line 136. With this arrangement, the breakthrough measurement device 144 is configured to measure an (e.g., focused) electrical discharge machining (EDM) voltage between the electrode guide 122 and the workpiece fixture 116 (or the electrode guide 122). This EDM voltage is also indicative of the gap voltage between the EDM electrode 120 and the workpiece 118 during the electrical discharge machining. However, whereas the EDM system voltage is also influenced by noise, resistance, etc. along the first line 132, the workpiece support 114 and the second line 136, the EDM voltage measured by the breakthrough measurement device 144 is closer to an actual value of the gap voltage. Moreover, the breakthrough measurement device 144 may be configured to measure the EDM voltage at a (e.g., high frequency) measurement frequency equal to or greater than ten kilohertz (10 kHz); e.g., between ten kilohertz (10 kHz) and fifteen kilohertz (15 kHz), between fifteen kilohertz (15 kHz) and twenty kilohertz (20 kHz), or between twenty kilohertz (20 kHz) and twenty-five kilohertz (25 kHz). Of course, it is contemplated the measurement frequency may be greater than twenty-five kilohertz (25 kHz).
The controller 112 is in signal communication with (e.g., hardwired and/or wirelessly coupled to) the EDM system 108 and the monitoring system 110. More particularly, the controller 112 is in signal communication with the electrode actuator 124, the power source 126, the EDM measurement device 138 and the breakthrough measurement device 144. The controller 112 may be implemented with a combination of hardware and software. The hardware may include a memory 150 and at least one processing device 152, which processing device 152 may include one or more single-core and/or multi-core processors. The hardware may also or alternatively include analog and/or digital circuitry other than that described above.
The memory 150 is configured to store software (e.g., program instructions) for execution by the processing device 152, which software execution may control and/or facilitate performance of the manufacturing method 500. The memory 150 may be a non-transitory computer readable medium. For example, the memory 150 may be configured as or include a volatile memory and/or a nonvolatile memory. Examples of a volatile memory may include a random access memory (RAM) such as a dynamic random access memory (DRAM), a static random access memory (SRAM), a synchronous dynamic random access memory (SDRAM), a video random access memory (VRAM), etc. Examples of a nonvolatile memory may include a read only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a computer hard drive, etc.
In step 502, referring to
In step 504, referring to
The aperture 154 formed during the electrical discharge machining step 504 may form at least a portion or an entirety of the respective cooling aperture 64 extending in the component substrate 74 of
In step 506, one or more parameters of the electrical discharge machining of the workpiece 118 are controlled based on the EDM system voltage. The EDM measurement device 138 of
In step 508, EDM electrode breakthrough is monitored for based on the EDM voltage. The breakthrough measurement device 144 of
In some embodiments, the controller 112 may determine the EDM electrode 120 has broken through the workpiece 118 during the electrical discharge machining of the workpiece 118. The controller 112 may then signal the EDM system 108 to terminate (end) the electrical discharge machining. For example, the controller 112 may signal the power source 126 to depower and the controller 112 may signal the electrode actuator 124 to retract the EDM electrode 120 from the now (e.g., fully) formed aperture 154 in the workpiece 118. Thus, the monitoring for the EDM electrode 120 breakthrough may be integrated into the electrical discharge machining process.
In some embodiments, the controller 112 (or another controller) may determine the EDM electrode 120 has broken through the workpiece 118 after the electrical discharge machining of the workpiece 118. For example, the electrical discharge machining of the workpiece 118 may be terminated using other parameters such as, but not limited to, length of travel of the EDM electrode 120 into the workpiece 118. Following the termination of the electrical discharge machining process, the controller 112 may process information associated with the monitored EDM voltage to verify whether or not the EDM electrode 120 broke through the workpiece 118 to completely form the aperture 154. Where the controller 112 determines breakthrough has occurred, the controller 112 may advance the manufacturing method to form one or more additional apertures in the workpiece 118. Where the controller 112 determines breakthrough has not occurred, the controller 112 may signal/control the EDM system 108 to reform (e.g., redrill) the aperture 154. Alternatively, another method may be utilized to determine EDM electrode breakthrough, and the determination of EDM electrode breakthrough utilizing the monitored EDM voltage may be used as a backstop (e.g., a double check) for the other breakthrough determination method. For example, following the electrical discharge machining, flow through the aperture 154 may be tested by pumping a fluid (e.g., a liquid or a gas) through the aperture 154 (or multiple apertures). Where the fluid flow through the aperture 154 (or multiple apertures) is different than expected, the controller 112 may process the monitored EDM voltage for the aperture 154 (or monitored EDM voltages for multiple apertures) to double check findings of the fluid flow breakthrough determination method. Here, the fluid flow may be inspected visually (e.g., where the fluid is the liquid) and/or using a thermal image (e.g., where the fluid is hot air). The present disclosure, however, is not limited to the foregoing exemplary other breakthrough determination methods.
In some embodiments, referring to
In some embodiments, each aperture 154 in the workpiece 118 may be individually and separately formed. In other embodiments, multiple apertures may be formed in the workpiece 118 simultaneously. In such embodiments, the EDM voltage may be measured and monitored for each of the EDM electrodes 120. Alternatively, the EDM voltage may be measured and monitored collectively for all (or a subset) of the EDM electrodes 120.
While various embodiments of the present disclosure have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the disclosure. For example, the present disclosure as described herein includes several aspects and embodiments that include particular features. Although these features may be described individually, it is within the scope of the present disclosure that some or all of these features may be combined with any one of the aspects and remain within the scope of the disclosure. Accordingly, the present disclosure is not to be restricted except in light of the attached claims and their equivalents.
