Patent Application
20120121382
The present invention generally relates to maintenance of devices using borescopes, and more particularly, but not exclusively, to borescope maintenance incorporating lasers.
Performing maintenance using borescopes remains an area of interest. Some existing systems have various shortcomings relative to certain applications. Accordingly, there remains a need for further contributions in this area of technology.
One embodiment of the present invention is a unique repair apparatus and method. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for repair of damaged gas turbine engine components. Further embodiments, forms, features, aspects, benefits, and advantages of the present application shall become apparent from the description and figures provided herewith.
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications in the described embodiments, and any further applications of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the invention relates.
With reference to
The borescope 56 can be used to provide images or other useful information of an area of interest in the workpiece 52, whether or not that area of interest is hidden from convenient view by one or more obstacles. Additionally and/or alternatively the borescope 56 can be coupled with or otherwise include useful devices for delivering material and/or manipulating objects of the workpiece 52 to the area of interest. The images or functions provided by the borescope 56 can occur near or proximate an end of the flexible member 54. In some applications the borescope 56, or portions thereof, can be located internal to the flexible member 54.
The directed energy member 58 is used to operate upon the workpiece 52 and can be coupled internal or external to the flexible member 54. In some applications the directed energy member 58 can be used to cut and/or heat the workpiece 52, join portions of the workpiece 52, or perform other construction processes such as repair and maintenance. Some additional non-limiting processes include welding, brazing, bonding, hole drilling, peening, metal build-up or metal addition, building-up, re-surfacing, surface cleaning, forming, heat treatment, and material removal. In the example of peening, it is possible to produce peened surfaces having no negative surface contour effects and a precise special distribution of residual stress. The energy delivered by the directed energy member 58 can be used for materials and processes requiring production of tailored microstructures, geometric features, surface finishes, and residual stresses.
The flexible member 54 can also be coupled with other devices such as those that enable gas, powder, and/or wire delivery. In some embodiments the maintenance device 50 can include motion, aiming, and locating controls for the borescope 56 and/or directed energy member 58. The maintenance device 50 can also include a material removal channel.
The maintenance device 50 can use the flexible member 54 in conjunction with the directed energy member 58 to perform a variety of tasks. In one non-limiting embodiment the maintenance device 50 can be used to remove material from the workpiece 52 using the directed energy member 58. The device 50 can also be used to build up a material upon the workpiece 52 using directed energy member 58 in conjunction with devices such as those that enable gas, powder, and/or wire delivery. Controls for moving, aiming, and locating the device 50, such as the borescope 56, can be used when removing material or adding material.
The directed energy member 58 can take the form of a laser which can be designed to laser objects in a variety of manners such as, but not limited to, continuous, pulse, or groupings of laser pulses. In one non-limiting form the groupings of pulses are formed as pairs. Each pulse in a pair of pulses can have a duration that may not be the same of the other pulse, although in some applications the pulses can have the same duration. Furthermore, the duration of either or both pulses in one pair can be the same or different than the duration of either or both pulses in another pair. In one embodiment the pulses can have a duration of about 3 nanoseconds (ns). The time interval between the pulses can be about 100 ns, but in some applications the time interval can be in a range of 30 ns to 150 ns. The time between pairs of pulses can be in a range of 100 microseconds (μs) to 100 milliseconds (ms). Similar to the pulse duration described above for individual pulses within a pair, the time interval between pulses and the time between pairs of pulses can vary with time as the laser develops successive pairings of pulses. In short, a great variety of duration, time interval, and time between pairs of pulses can be implemented with the directed energy member 58.
The embodiments of the laser can take a variety of forms and have a variety of characteristics. The laser can be one of Nd:YAG, CO2, disk, or fiber. In addition, in some non-limiting forms the peak power of each laser pulse, such as the peak power of a 3 ns pulse, could reach 750 kW with a total energy of 2.4 milliJoule (mJ) and an intensity of 4×1010 Watts per square centimeter (W/cm2). In some forms a laser fiber having approximately 1 millimeter (mm) diameter can deliver average output power up to 8 kilowatts (kW). In certain applications, Q-switched fiber lasers can offer up to 2 mJ energy per pulse with peak power of more than 50 kilowatts (kW). Furthermore, any given pulse of the laser can have a unique power, energy, and intensity. It is also possible to have a repeating pattern of power, energy, and intensity. In short, like the variations described above regarding duration, time interval, and time between pairs of pulses, the pulses can also have variation in their power, energy, and intensity.
The directed energy member 58 can be moved at a variety of rates to affect a cut, or other procedure, upon the workpiece 52. The rate at which the directed energy member 58 is moved can be dependent upon thickness and material composition, among other attributes and/or criteria. In some applications the directed energy member 58 can be moved in a range of 0.2 mm per minute to 1.0 mm per minute.
The relative timing and grouping of pulses can be used on a workpiece 52 to discourage the formation of at least one of a material recast, stress concentrators, a heat affected zone, microcracking, re-deposition, and re-solidification. In the groupings of pulses described above the first one of the pulses is capable of producing debris, and in some cases can additionally or alternatively produce fast moving plasma. The plasma can dissipate after application of the first one of the pulses but the other debris can remain over the area of interest during the delay period between the first one of the pulses and the second one of the pulses. The second one of the pulses can be used to dissipate the debris such as through, but not limited to, vaporization. In some forms the second pulse can be used to superheat the debris. In some applications the debris can be completely dissipated, while in other applications the debris may only be partly dissipated.
The application of the directed energy member 58 by the maintenance device 50 of the present application can be performed in the presence of a working fluid which, in one form, is air but other working fluids are also contemplated. In some applications the maintenance device 50 can receive the assistance of an air flush onto the area of interest which can encourage the reduction of debris.
In one embodiment the workpiece 52 is a gas turbine engine 60 that includes a gas turbine engine inspection opening 62. The opening 62 can be a purpose designed access hole or an opening created by removing a panel or door or any other such hole through which the flexible member 54 can pass. In one form the opening 62 is a borescope inspection port. The opening 62 can take on a variety of shapes not limited to square and circle, and in some forms can have a dimension such as a diameter in the range of 4 mm to 10 mm. The flexible member 54 can be inserted into the opening 62 and be directed to an area of the gas turbine engine 60 to be operated upon by the borescope 56, the directed energy member 58, or other device coupled to the flexible member 54 to facilitate processing as described above. The gas turbine engine 60 can include, among other features, a compressor 64, combustor 66, and turbine 68. In one non-limiting example, the directed energy member 58 can be applied to a blade of the compressor 64 to affect a repair from foreign object damage. In some embodiments the workpiece 52 can include an aircraft (not shown) having the gas turbine engine 60 wherein the maintenance device 50 can be positioned relative to either to affect a process such as one described above.
Turning now to
Once an assessment is made in Operation 110, a decision is made whether a repair should be scheduled in Conditional 115. If a repair isn't scheduled, Procedure 100 returns to the start. With a positive response to Conditional 115, Procedure 100 continues with Operation 120 where one embodiment of the maintenance device 50 is transported to where it is required in the repair field. Such an embodiment could be a fully flexible fiber-hosted laser borescope system having any of the variations discussed above. The maintenance device 50 can be mobile to allow the directed energy member 58 to be operated in a repair field to allow repairs to components while the engine is still assembled to a structure of an aircraft.
After the maintenance device 50 is transported in Operation 120 and ready for set up, Operation 130 continues with inserting the flexible member 54 including the directed energy member 58, borescope 56, and any additional process device deemed necessary into an access hole in the workpiece 52 being repaired. Once the flexible member 54 has been inserted, the directed energy member can be flexed and bent around obstacles to reach a desired repair location. The borescope portion of the maintenance device 50 can aid in placement of the directed energy member 58.
An image of the repair location is taken in Operation 140. The image is then analyzed to determine a repair schedule in Operation 150. The repair schedule can include the selection of laser type, laser power, or laser speed to name just a few. The repair schedule can also determine the location and path of the laser and any other factors necessary to operate the desired repair.
Operation 160 starts the laser process by emitting the first laser pulse of a grouping of pulses at particular strength for a particular duration. Operation 162 follows Operation 160 with a dwell time between pulses, also referred to as an inter-pulse interval. The inter-pulse interval is followed by Operation 164 which emits the second laser pulse at a strength and duration for the second pulse. Operation 164 is followed by Operation 166 with a dwell time between groupings of pulses, also referred to as an inter-pair interval. During Operation 166, Operation 170 can be initiated to assess the progress of the repair. Conditional 180 decides whether the laser process should continue by repeating Operations 160 thru 170 or should stop thus signifying that the repair is complete.
To demonstrate the laser for potential repair applications such as in-situ, on-wing repairs of a gas turbine engine, laser cutting trials were performed on Ti and Ni alloy HPC blades. In one embodiment technical requirements for potential on-wing applications included no recast layer and no metal splatter from the laser-cutting process.
A Double-Nanosecond-Pulse Laser process using a flexible fiber-hosting laser boroscope system was used to cut a high pressure compressor (HPC) Ti 679 blades and HPC Inco 718 blades representative of potential on-wing care/repair applications. This embodiment used a prototype Nd:YAG laser system with Double-Nanosecond-Pulse settings. The laser cutting rates for the HPC blades were in a range of 0.2 mm/minute to 1.0 mm/minute depending on the thickness and material.
During the laser cutting process, material is heated to temperatures far beyond the boiling point, therefore metal droplet transfer was very limited and no re-depositions or splatters were produced. Some discoloration was observed on the laser cut edges of both the Inco 718 and the Ti 679 blade.
Metallographic evaluation of the cut edges for the previously presented sample was performed. Results indicated that no continuous recast layers exist at the laser cut edges of both the Inco 718 and Ti 679 blades. There may be some isolated recast spots with a dimension of about 0.5 μm (0.02 mil) for the Ti 679 blades and about 1.0 μm (0.04 mil) for the Inco 718 blades, respectively, shown in
The recast layer for the dual-pulse laser technique is significantly less than the one resulting from conventional laser cutting processes.
One aspect of the present application is an apparatus including a borescope inspection device having a flexible tube that includes an inspection end sized to be inserted through a borescope inspection port of a gas turbine engine which may be positioned on a structure of an aircraft and a coherent electromagnetic energy device including a double pulse laser operable to emit a pair of limited duration laser pulses and possibly at least one fully flexible fiber-hosted laser. The coherent electromagnetic energy device is coupled with the borescope inspection device and is operable to be inserted through the borescope inspection port in proximity with the flexible tube of the borescope inspection device.
A further feature includes the double pulse laser operable to emit a pair of limited duration laser pulses being further capable of affecting a repair at a repair location on the gas turbine engine. The double pulse laser can be operated with an inter-pulse interval time between a first pulse and a second pulse greater than a pulse duration of either the first pulse or the second pulse. In operation the laser can produce a quantity of debris from the repair location of the gas turbine engine which is then superheated to reduce and/or eliminate a recast layer in the repair location of the gas turbine engine. This can also include providing no continuous recast layer and providing a surface finish that meets a surface finish threshold on the repair location of the gas turbine engine.
The inter-pulse interval time may be within a range of 30 ns and 150 ns and an inter-pair interval time is in a range between 100 μs and 100 ms. A process device may also be included which is capable of aiding the coherent electromagnetic energy device to affect a repair at a repair location on the gas turbine engine where the coherent electromagnetic energy device and the process device are coupled with the borescope inspection device and operable to be inserted through the borescope inspection port in proximity with the flexible tube of the borescope inspection device. The coherent electromagnetic energy device may include a laser delivery fiber with a 1.0 mm diameter providing an average output power up to 8 kilowatts.
Another embodiment of the present application is an apparatus including a borescope inspection device having a flexible tube that includes an inspection end sized to be inserted through a borescope inspection port of a gas turbine engine which may be positioned on a structure of an aircraft and a coherent electromagnetic energy device including a double pulse laser which may include at least one fully flexible fiber-hosted laser with a 1.0 mm diameter providing an average output power up to 8 kilowatts. The coherent electromagnetic energy device is coupled with the borescope inspection device and is operable to insert the flexible tube of the borescope inspection device through the inspection port of the gas turbine engine. The borescope inspection device can image a repair location of a gas turbine engine component and the coherent electromagnetic energy device can emit a pair of limited duration laser pulses to affect a repair at the repair location. The double pulse laser system can include an interval time between a first pulse and a second pulse greater than a duration time of either the first pulse or the second pulse and can produce a quantity of debris from the repair location of the gas turbine engine component. The debris can be superheated to eliminate a recast layer in the gas turbine engine component.
Yet another embodiment is for a method including inserting a flexible tube of a borescope inspection device through an inspection port of a gas turbine engine, the flexible tube having an end compatible with a coherent electromagnetic energy device including a double pulse laser; imaging a repair location of a gas turbine engine component with the borescope inspection device; emitting a pair of limited duration laser pulses from the coherent electromagnetic energy device to affect a repair at the repair location, the double pulse laser having an interval time between a first pulse and a second pulse greater than a pulse duration of either the first pulse or the second pulse; producing a quantity of debris from the repair location of the gas turbine engine component; and superheating the quantity of debris to eliminate a recast layer in the gas turbine engine component. The inspection port can further include an opening for a first engine stage and inserting the flexible tube further includes accessing a second engine stage through the inspection port of the first stage. Elimination of the recast layer may further include providing the formation of no continuous recast layer and providing a surface finish on the repair location of the gas turbine engine. The emission of the pair of limited duration laser pulses may be performed in air or with an air flush.
In another aspect the present application provides an apparatus for emitting electromagnetic energy via an emitting end for repairing a component, the apparatus comprising an inspection device having a flexible extension that includes an inspection end sized to be inserted through an inspection opening of an assembly to be repaired, and a coherent electromagnetic energy device including a double pulse laser configured to emit successive pairings of limited duration laser pulses, the coherent electromagnetic energy device coupled with the flexible extension of the inspection device and operable to be inserted through the inspection port of the assembly.
In still a further aspect the present application provides an apparatus comprising a gas turbine engine construction device having a flexible borescope capable of capturing an image of a component to be operated upon and a laser positioned proximate an end of the flexible borescope to emit successive pairings of laser energy pulses, a first pulse of a pairing operable to produce an ejecta from the component and a second pulse of the pairing operable to disperse the ejecta to improve material processing properties.
In yet still a further aspect the present application provides an apparatus comprising an inspection and repair device having a flexible portion configured to convey a borescope and a laser, the laser including means to discourage a recast layer when a laser energy is irradiated upon a repair component.
In still another aspect the present application provides a method comprising inserting a flexible portion of a borescope inspection device through an inspection port of a gas turbine engine, the flexible portion having an end coupled with a coherent electromagnetic energy device including a double pulse laser, emitting a pair of limited duration laser pulses from the coherent electromagnetic energy device to affect a change in physical state of a portion of the gas turbine engine, producing a quantity of debris from a location of the gas turbine engine component as a result of a first pulse of the double pulse laser irradiating the gas turbine engine, and heating the quantity of debris with a second pulse of the double pulse laser.
While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the inventions are desired to be protected. It should be understood that while the use of words such as preferable, preferably, preferred or more preferred utilized in the description above indicate that the feature so described may be more desirable, it nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, the scope being defined by the claims that follow. In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and/or “a portion” is used the item can include a portion and/or the entire item unless specifically stated to the contrary.
