Patent Description:
A cold spray gun can itself be additively manufactured by using a direct metal deposition process to form the intricate internal passages that are used in a cold spray gun, while also having the material properties that enable many operating cycles of use. However, over the operating lifetime of a cold spray gun, cyclic stress loading can degrade the microcrystalline structure of the cold spray gun material, eventually leading to material failure. It is desirable to condemn a cold spray gun prior to it reaching a point of catastrophic material failure during operation. On the other hand, because of the cost of a cold spray gun, it is desirable to extract a maximum useful operating lifetime from it. Therefore, it is desirable to have a means of monitoring the health of an additively manufactured cold spray gun in order to maximize its service life.

A prior art system for estimating remaining operational life of high temperature components is disclosed in <CIT>. Here, alloy-based witness coupons and diffusion couple witness coupons are attached to, or directly applied onto, gas turbine components so that they experience the same high temperature operation and shut down as the components themselves. The witness coupons are later removed from the components and analyzed, or are analyzed on the component, to determine the change to their microstructure, metallurgy, and/or diffusion characteristics.

Further prior art health monitoring systems are disclosed in <CIT>, <CIT> and <CIT>.

A method for monitoring a lifecycle of an additively manufactured cold spray gun is provided, as set forth in claim <NUM>.

A cold spray gun is additively manufactured by using a direct metal deposition (DMD) process, thereby forming the intricate internal passages that are used in a cold spray gun. Laser powder bed fusion can typically be used as the DMD process to fabricate a cold spray gun, with the resulting material being a metal matrix composite (MMC) having a microcrystalline material structure. Non-limiting examples of materials that can be used to form the MMC include metals, metal alloys, and/or mixtures of metals, metal oxides, ceramics, fibers, and other materials.

After being fabricated, the cold spray gun can have material properties that enable many operating cycles of use. However, over the operating lifetime of a cold spray gun, the cyclic stress loading can degrade the microstructure of the cold spray gun material, eventually leading to material failure. It is desirable to condemn a cold spray gun prior to it reaching a point of catastrophic material failure during operation. On the other hand, because of the cost of a cold spray gun, it is desirable to extract a maximum useful operating lifetime from it. Because laser powder bed fusion and other related processes of additive manufacturing are developing technologies, the material properties of the microcrystalline material structure are not well understood. In particular, it is difficult to predict with accuracy the serviceable lifetime of a cold spray gun when subjected to cyclic temperature and pressure stresses over time.

The present disclosure provides a health monitoring method for an additively manufactured cold spray gun having a microcrystalline material structure that is subject to cyclic stress loading.

<FIG> is a perspective view of an additively manufactured cold spray gun showing the health monitoring system. <FIG> is an enlarged perspective view of health monitoring system <NUM> in <FIG> is a perspective view of a removed health monitoring coupon <NUM>' from <FIG>. Shown in <FIG> are cold spray gun <NUM>, gun barrel <NUM>, gun neck <NUM>, nozzle connector <NUM>, mounting flange <NUM>, flange apertures <NUM>, gas inlet port <NUM>, material inlet port <NUM>, health monitoring feature <NUM>, flat base <NUM>, health monitoring coupons <NUM>, and health monitoring coupon <NUM>'. Cold spray gun <NUM> has been additively manufactured by using a DMD process, and includes gun barrel <NUM>, gun neck <NUM>, nozzle connector <NUM>, and mounting flange <NUM>. During the operation of cold spray gun <NUM>, gas inlet port <NUM> receives a hot pressurized working gas (not shown), and material inlet port <NUM> receives a supply of solid powder (not shown). During operation, the temperature and pressure of the hot pressurized working fluid can approach <NUM> deg. C (<NUM> deg. F) and <NUM>,<NUM> KPa (<NUM> psi), respectively. During operation, the solid powder is entrained in the hot pressurized working gas in the interior of gun barrel <NUM> and accelerated to a hypersonic velocity within the interior of gun neck <NUM>. The velocity of accelerated solid powder can reach <NUM>,<NUM>/s (<NUM>,<NUM> miles/hr). When not being operated, cold spray gun <NUM> can cool to ambient temperature. An exemplary ambient temperature is <NUM> deg. C (<NUM> deg. Accordingly, in the illustrated embodiment, the temperature range, which is defined as the difference between the maximum and minimum temperature of cold spray gun <NUM>, can be <NUM> deg. C (<NUM> deg. Similarly, in the illustrated embodiment, the pressure range, which is defined as the difference between the maximum and minimum pressure of cold spray gun <NUM>, can be <NUM>,<NUM> KPa (<NUM> psi). In other embodiments, the temperature range can be between <NUM> deg. C (<NUM> deg. F) - <NUM> deg. C (<NUM> deg. F), and the pressure range can be between <NUM> KPa (<NUM> psi) - <NUM>,<NUM> KPa (<NUM> psi).

During operation, a nozzle (not shown) is attached to cold spray gun <NUM> by means of nozzle connector <NUM>, thereby allowing the accelerated solid powder to be directed at a target (not shown). In the illustrated embodiment, nozzle connector <NUM> is threaded, thereby allowing a nozzle to be threadably connected to cold spray gun <NUM>. A benefit of threadably attaching a nozzle to nozzle connector <NUM> is to allow for the repeated removal and reattachment of the nozzle. Cold spray gun <NUM> is held in position by affixing mounting flange <NUM> to a suitable fixture (not shown). Flange apertures <NUM> allow threaded fasteners (not shown) to be used to affix mounting flange <NUM> to the suitable fixture. A benefit of threadably attaching mounting flange <NUM> to a suitable fixture is to allow for the repeated removal and reattachment of cold spray gun <NUM>. In an embodiment, for example, the suitable fixture can be a robotic arm (not shown) that is used to maneuver cold spray gun <NUM> in the vicinity of the target. In an exemplary embodiment, the hot pressurized working gas can be helium. In other embodiments, the hot pressurized working gas can be any other gas, or a mixture of gasses that can include helium, argon, and/or nitrogen. In an exemplary embodiment, the solid powder can be metals, alloys, polymers, ceramics, composite materials, and nanocrystalline materials.

During operation of cold spray gun <NUM>, the interior of gun barrel <NUM> experiences the temperature and pressure of the hot pressurized working gas. During operation, gun barrel <NUM> functions as a pressure vessel to contain the hot pressurized working gas. In the illustrated embodiment, gun barrel <NUM> has the greatest circumferential dimension of cold spray gun <NUM> and can therefore experience the greatest tensile pressure stress loading from the hot pressurized working gas. Moreover, because gun barrel <NUM> functions as a pressure vessel, it must have a wall thickness that is sufficient to endure the tensile pressure stress loading during operation. Accordingly, during heat-up at the beginning of operation from ambient temperature to that of the hot pressurized working gas, and during cool-down following operation, gun barrel <NUM> can experience thermal stress loading from the heat-up rate and cool-down rate. The thermal stress profile can include regions that are under tensile stress, compressive stress, or both. Therefore, the microcrystalline material structure of gun barrel <NUM> can be susceptible to the greatest stress loading experienced by cold spray gun <NUM>, and it can therefore experience the greatest material degradation over the lifecycle of cold spray gun <NUM>. Over the lifetime of cold spray gun <NUM>, the material degradation can lead to material failure. In an extreme case, catastrophic failure can occur, possibly resulting in damage to other components.

The physical dimensions of cold spray gun <NUM> can vary widely. For example, in a typical embodiment, cold spray gun <NUM> can have a length (not labeled) of approximately <NUM> (<NUM> in), and gun barrel <NUM> can have a diameter (not labeled) of approximately <NUM> (<NUM> in). In other embodiments, cold spray gun <NUM> can have sizes that are greater than or less than the aforementioned exemplary dimensions. Moreover, in other embodiments, cold spray gun <NUM> can have shapes and features that are different from the exemplary shape depicted in <FIG>.

Referring again to <FIG>, health monitoring feature <NUM> is located on the outer surface of gun barrel <NUM>. Health monitoring feature <NUM> is manufactured integrally with cold spray gun <NUM> by means of a DMD process described earlier, and is therefore made of the same material and subject to the same material degradation as gun barrel <NUM> (and accordingly, as cold spray gun <NUM>). In the illustrated embodiment, cold spray gun <NUM> has been additively manufactured using laser powder bed fusion, thereby resulting in a microcrystalline material structure. In other embodiments, cold spray gun <NUM> can be additively manufactured using other DMD processes that result in a microcrystalline material structure.

Referring to <FIG>, health monitoring system <NUM> includes flat base <NUM> and one or more health monitoring coupons <NUM>. Flat base <NUM> is a transition region between the curved outer profile of gun barrel <NUM> and health monitoring coupons <NUM>. Accordingly, health monitoring coupons <NUM> are built out as planar elements from flat base <NUM>. In the illustrated embodiment, three health monitoring coupons are included in health monitoring system <NUM>. In some embodiments, fewer than three health monitoring coupons <NUM> can be included in health monitoring system <NUM>. In other embodiments, more than three health monitoring coupons <NUM> can be included in health monitoring system <NUM>. In yet other embodiments, health monitoring system <NUM> can omit flat base <NUM>. In the illustrated embodiment, health monitoring system <NUM> is located on a first region of gun barrel <NUM>. In other embodiments, a second health monitoring system <NUM> can be located on a second region of gun barrel <NUM>. For example, in one of these other embodiments, a second health monitoring system <NUM> can be located on the opposite (or distal) side of gun barrel <NUM> from the first health monitoring system <NUM> shown in <FIG>. In yet other embodiments, a health monitoring system <NUM> can be included on any region of cold spray gun <NUM>. An advantage of including more than three health monitoring coupons <NUM> in health monitoring system <NUM>, and/or of including more than one health monitoring system <NUM> on cold spray gun <NUM>, can be to provide a higher resolution of data in monitoring the lifecycle of cold spray gun <NUM>. That is, by providing a greater total number of health monitoring coupons <NUM> on cold spray gun <NUM>, successive health monitoring coupons <NUM> can be analyzed at a more frequent interval throughout the service life of cold spray gun <NUM>. Accordingly, there is no firm upper limit to the number of health monitoring coupons <NUM> that can be located on an additively manufactured component.

As described above, health monitoring feature <NUM> is subjected to transient and operational pressure and temperature stresses throughout the lifecycle of cold spray gun <NUM>. Therefore, health monitoring system <NUM> can experience the same material degradation of its microcrystalline material structure as cold spray gun <NUM>. Various inspection methods can be used to assess the existence, and if so, the extent of changes in the microcrystalline material structure of health monitoring system <NUM> over the operational lifetime of cold spray gun <NUM>. Inspecting or analyzing microcrystalline material structural changes in health monitoring coupon <NUM> of health monitoring system <NUM> can therefore provide an indication of the health of cold spray gun <NUM>. These inspections can be used to determine when cold spray gun <NUM> should be condemned, thereby removing it from service prior to reaching the point of material failure.

Health monitoring coupon <NUM> is removed from health monitoring system <NUM> for inspection and analysis of its microcrystalline material structural to determine the extent of changes which may have occurred. In the illustrated embodiment, three health monitoring coupons <NUM> are available for removal and analysis during the service life of cold spray gun <NUM>. As will be described in <FIG>, an algorithm can be used to determine when a first health monitoring coupon <NUM> is to be removed, and when subsequent health monitoring coupons <NUM> are to be removed. Several factors can be considered in making this determination, with non-limiting examples of these factors including the operating parameter history of cold spray gun <NUM>. For the sake of the present description, a determination has been made at a particular point in the service life of cold spray gun <NUM> to remove a health monitoring coupon <NUM> for analysis. In the illustrated embodiment, a first (or successive) health monitoring coupon <NUM> is removed from cold spray gun <NUM> by electrical discharge machining (EDM). EDM is a precision machining method that can be used for precisely removing health monitoring coupon <NUM> from health monitoring system <NUM>. In other embodiments, other precision machining methods can be used to remove health monitoring coupon <NUM> from health monitoring system <NUM>. For example, non-limiting examples of other precision machining methods include mechanical cutting with a band saw and laser cutting with a laser beam. As can be seen in <FIG>, flat base <NUM> provides a planar datum that is used for removing health monitoring coupon <NUM>.

Referring to <FIG>, health monitoring coupon <NUM>' is labeled with dimensions of width w, height h, and thickness t. In an exemplary embodiment, health monitoring coupon <NUM>' can have a width w and height h of about <NUM> (<NUM> in) each. In some embodiments, width w and height h can be between <NUM> (<NUM> in) - <NUM> (<NUM> in) each. In other embodiments, width w and height h can be different from each other, and either width w and/or height h can be less than <NUM> (<NUM> in) or greater than <NUM> (<NUM> in). In other embodiments, health monitoring coupons <NUM> can have any geometric shape other than rectangular (and therefore, other than square). Accordingly, health monitoring coupon <NUM>' (after being removed from health monitoring feature <NUM>) can have any geometric shape.

In an exemplary embodiment, health monitoring coupon <NUM>' can have a thickness t between approximately <NUM> (<NUM> in) - <NUM> (<NUM> in). In a particular embodiment, thickness t can be about <NUM> (<NUM> in). In other embodiments, thickness t can be less than <NUM> (<NUM> in) or greater than <NUM> (<NUM> in). In yet other embodiments, health monitoring coupon <NUM>' can have a non-uniform thickness t. In these other embodiments, non-uniform thickness t can result from either intentionally or unintentionally using a precision machining process that results in non-uniform thickness t. For example, it can be possible that during the removal of health monitoring coupon <NUM>' the EDM plane is not parallel to flat base <NUM>. Accordingly, health monitoring coupon <NUM>' can have a non-uniform thickness t.

In an exemplary embodiment, once a triggering event occurs to prompt a user to remove a first health monitoring coupon <NUM>, cold spray gun <NUM> would first be shut down and removed from the fixture as described above in <FIG>. Health monitoring coupon <NUM>' would then be inspected and/or analyzed for indications of change to the microcrystalline material structure. The results of the inspection and/or analysis of health monitoring coupon <NUM>' are used to determine the extent of changes to the microcrystalline material structure of cold spray gun <NUM>, because health monitoring coupon <NUM>' provides a representative sample of the material of cold spray gun <NUM>, as described above in <FIG>. Accordingly, the results of the inspection and/or analysis of health monitoring coupon <NUM>' help a user determine whether cold spray gun <NUM> is in a serviceable condition or should be condemned. If cold spray gun <NUM> is deemed to be in a serviceable condition, cold spray gun <NUM> is returned to operation. The results of the inspection and/or analysis of health monitoring coupon <NUM>' can be included as a factor, in addition to the monitoring of operating parameters, in determining when the next health monitoring coupon <NUM> should be removed. The foregoing description of removing health monitoring coupon <NUM> is predicated on being able to support cold spray gun <NUM> in a suitable machining position for performing a suitable precision machining method for removing health monitoring coupon <NUM>. In the illustrated embodiment, the removal of cold spray gun <NUM> from the cold spray system (not shown) is required in order to remove health monitoring coupon <NUM>. In other embodiments, health monitoring coupon could be removed in situ by bringing the EDM equipment to the operating location of cold spray gun <NUM>.

Various inspection and analysis techniques can be used on health monitoring coupon <NUM>' to determine the extent of changes to the microcrystalline material structure. For example, a visual inspection can be performed to determine if there are any visually observable cracks in health monitoring coupon <NUM>'. A visual inspection can be performed with or without magnification. A liquid dye penetrant test can be performed, which can provide an indication of micro-cracks in health monitoring coupon <NUM>'. Radiologic computed tomographic (CT) imaging, X-ray imaging, and/or X-ray diffraction imaging can be performed to provide an indication of the internal structure of health monitoring coupon <NUM>'. Other nondestructive and/or destructive testing methods can be performed on health monitoring coupon <NUM>', with non-limiting examples including eddy current testing, magnetic particle testing, ultrasonic testing, fracture toughness testing, and yield strength testing. Any form of inspection, analysis, and testing on health monitoring coupon <NUM>' to determine the existence and scope of changes to the microcrystalline material structure is within the scope of the present disclosure.

On the other hand, if the results of the inspection and/or analysis of health monitoring coupon <NUM>' determine that cold spray gun <NUM> should be condemned and removed from service, a new cold spray gun <NUM> can be installed and used. The condemnation of cold spray gun <NUM> therefore allows cold spray gun <NUM> to undergo additional testing, including destructive testing. For example, hydrostatic pressure testing could be performed on cold spray gun <NUM>. Moreover, cold spray gun <NUM>, or particularly, gun barrel <NUM>, could be cross-sectioned thereby allowing for inspection of the interior microcrystalline structure. Collectively, these analysis techniques can be referred to as failure analysis. The results of the failure analysis on cold spray gun <NUM> can be used to determine future inspection intervals for health monitoring coupons <NUM> on subsequently installed cold spray guns <NUM>.

<FIG> is a front end view of cold spray gun <NUM> of <FIG>. Shown in <FIG> are cold spray gun <NUM>, gun barrel <NUM>, mounting flange <NUM>, health monitoring system <NUM>, flat base <NUM>, and health monitoring coupon <NUM>. The description of cold spray gun <NUM>, gun barrel <NUM>, mounting flange <NUM>, health monitoring system <NUM>, flat base <NUM>, and health monitoring coupon <NUM> are as provided in <FIG>. Health monitoring coupon <NUM> protrudes outward from flat base <NUM> by distance d. In an exemplary embodiment, distance d can be between approximately <NUM> (<NUM> in) - <NUM> (<NUM> in). In a particular embodiment, distance d can be about <NUM> (<NUM> in). In other embodiments, distance d can be less than <NUM> (<NUM> in) or greater than <NUM> (<NUM> in). It is to be appreciated that the precision machining method that was described in <FIG> removes some amount of material in its process. Therefore, distance d will generally be greater than thickness t as described in <FIG>. For example, in an exemplary embodiment, EDM uses a wire that is about <NUM> (<NUM> in) in diameter. Therefore, in this exemplary embodiment, distance d can be about <NUM> (<NUM> in) greater than thickness t as shown in <FIG>.

In the embodiment illustrated in <FIG>, cold spray gun <NUM> includes a single health monitoring feature <NUM>. In other embodiments, cold spray gun <NUM> can include two or more health monitoring features <NUM>. For example, in one of these other embodiments, a second health monitoring feature <NUM> could be located on the side of gun barrel <NUM> that is opposite a first health monitoring system <NUM>. In other embodiments, a second, third, or more health monitoring feature could be located anywhere on cold spray gun <NUM>. In some of these embodiments, all health monitoring features <NUM> could be similar to each other. In other embodiments, at least one health monitoring feature <NUM> could be different from another health monitoring feature <NUM>. These differences could include any of the following: the number of health monitoring coupons <NUM>, the width w, height h, and/or distance d of health monitoring coupons <NUM>, and the geometric shape of health monitoring coupons <NUM>.

<FIG> is a flowchart diagram depicting the health monitoring lifecycle of cold spray (CS) gun <NUM> in <FIG>. Shown in <FIG> are health monitoring lifecycle <NUM>, and the following steps: install new CS gun step <NUM>, monitor operating parameters step <NUM>, generate sample trigger step <NUM>, remove CS gun step <NUM>, remove health monitoring coupon step <NUM>, analyze health monitoring coupon step <NUM>, make CS gun usability decision <NUM>, reinstall CS gun step <NUM>, replace CS gun step <NUM>, and perform failure analysis on CS gun step <NUM>. In the illustrated embodiment, health monitoring lifecycle <NUM> begins with install new CS gun step <NUM>, depicting the installation of a new cold spray gun <NUM> in a cold spray manufacturing, repair, or refinishing system (not shown). As cold spray <NUM> gun operates, various operating parameters are monitored in monitor operating parameters step <NUM>. In the illustrated embodiment, the various operating parameters that are monitored include the number of startup cycles (and accordingly, the number of shutdown cycles), the operating time for each operating cycle, the temperature range for each operating cycle, and the pressure range for each operating cycle. In some embodiments, fewer than these enumerated operating parameters can be monitored. For example, in some embodiments, it can be sufficient to monitor only the cumulative operating time of cold spray gun <NUM>. In other embodiments, additional operating parameters can be monitored. Non-limiting examples of additional operating parameters can include the rate of pressurization and depressurization of cold spray gun <NUM>, the heat-up and cool-down rates of cold spray gun <NUM>, the type of working gas used in cold spray gun <NUM>, and the size and composition of the powder used in cold spray gun <NUM>.

Generate sample trigger step <NUM> receives input from monitor operating parameters step <NUM> to determine when the operator should remove a health monitoring coupon <NUM>. In the illustrated embodiment, monitoring operating parameters step <NUM> receives a continuous input of the various operating parameters, and an algorithm calculates when a sample trigger should be generated. In other embodiments, monitoring operating parameters step <NUM> can intermittently receive inputs of the various operating parameters for calculating when the sample trigger should occur. In some of these other embodiments, some operating parameters can be sampled at frequencies that are different than other operating parameters.

Referring back to <FIG>, upon receiving the trigger alert from generate sample trigger step <NUM>, remove CS gun step <NUM> directs the operator to shut down and remove cold spray gun <NUM> from the cold spray system. In the illustrated embodiment, remove CS gun step <NUM> can be performed at the next convenient opportunity, for example, at the end of a cold spray cycle or following the completion of a work shift. After completing remove CS gun step <NUM>, remove health monitoring coupon step <NUM> directs the operator to remove a first health monitoring coupon <NUM> from health monitoring system <NUM>. After being removed from health monitoring system <NUM>, health monitoring coupon <NUM>' can be evaluated for indications of change to the microcrystalline material structure. Analyze health monitoring coupon step <NUM> directs the operator to inspect, analyze, and/or evaluate health monitoring coupon <NUM>' as described above in <FIG>. The results of this analysis are used to determine the fate of cold spray gun <NUM>. Make CS gun usability decision <NUM> provides a yes/no decision on whether cold spray gun <NUM> can continue to be used in operation. If cold spray gun <NUM> is deemed to be usable, reinstall CS gun step <NUM> directs the operator to re-install cold spray gun <NUM>. Additionally, the analysis results can be provided as a health assessment input to monitor operating parameters step <NUM>. After completing reinstall CS gun step <NUM>, monitor operating parameters step <NUM> resumes. In some embodiments, health monitoring coupon <NUM> can be removed from cold spray gun <NUM> in situ, without first removing and subsequently reinstalling cold spray gun <NUM> from the cold spray system. In these embodiments, remove CS gun step <NUM> and reinstall CS gun step <NUM> can be omitted.

On the other hand, if cold spray gun <NUM> is not deemed to be usable, then cold spray gun <NUM> must be condemned. Accordingly, replace CS gun step <NUM> directs the operator to install a new cold spray gun <NUM> in the cold spray system. After replace CS gun step <NUM> is performed, monitor operating parameters step <NUM> resumes. Finally, the condemned cold spray gun <NUM> can be subjected to further testing and analysis. Perform failure analysis on CS gun step <NUM> directs the operator to perform additional analysis on cold spray gun <NUM>, as described above in <FIG>. Moreover, the data obtained in health monitoring lifecycle <NUM> can be used to optimize future health monitoring lifecycles <NUM> for subsequent cold spray guns <NUM>, and in particular, to optimize monitor operating parameters step <NUM> for optimally determining when to remove health monitoring coupons <NUM> in generate sample trigger step <NUM>. In the illustrated embodiment, perform failure analysis on CS gun step <NUM> is typically performed at the end of life of cold spray gun <NUM>. In other embodiments, perform failure analysis on CS gun step <NUM> is an optional step that is not necessary to be performed following the condemnation of every cold spray gun <NUM>. For example, perform failure analysis on CS gun step <NUM> can be beneficial when cold spray gun <NUM> has a different size or shape, is manufactured from a different composition, and/or has operated under different operating parameters than previous cold spray guns <NUM>.

In the illustrated embodiment, health monitoring lifecycle <NUM> is unique for each particular embodiment of cold spray gun <NUM>. For example, if health monitoring system <NUM> includes a greater number of health monitoring coupons <NUM> than in the illustrated embodiment, and/or if cold spray gun <NUM> includes more than one health monitoring system <NUM> as in the illustrated embodiment, then generate sample trigger step <NUM> can be programmed to trigger at a greater frequency. Further, health monitoring lifecycle <NUM> can be different for a different design of cold spray gun <NUM>, with differences being determined based of size, shape, style, and/or the type of MMC, and therefore the microcrystalline material structural, that is used in cold spray gun <NUM>. Moreover, as noted earlier, health monitoring system <NUM> of the present disclosure can be used on any additively manufactured component having a microcrystalline material structure that is subject to cyclic stress loading. Accordingly, in these other embodiments, health monitoring lifecycle <NUM> can be adjusted to accommodate the various components on which health monitoring system <NUM> is used.

Referring back to <FIG>, health monitoring lifecycle <NUM> runs in an electronic computing device in the illustrated embodiment. In terms of hardware architecture, such a computing device can include a processor, a memory, and one or more input and/or output (I/O) device interface(s) that are communicatively coupled via a local interface. The local interface can include, for example but not limited to, one or more buses and/or other wired or wireless connections. The local interface may have additional elements, which are omitted for simplicity, such as controllers, buffers (caches), drivers, repeaters, and receivers to enable communications. Further, the local interface may include address, control, and/or data connections to enable appropriate communications among the aforementioned components.

The aforementioned processor can be a hardware device for executing software, particularly software stored in memory. The processor can be a custom made or commercially available processor, a central processing unit (CPU), an auxiliary processor among several processors associated with the computing device, a semiconductor based microprocessor (in the form of a microchip or chip set) or generally any device for executing software instructions. The memory can include any one or combination of volatile memory elements, e.g., random access memory (RAM, such as DRAM, SRAM, SDRAM, VRAM, etc.) and/or nonvolatile memory elements, e.g., ROM, hard drive, tape, CD-ROM, etc. Moreover, the memory may incorporate electronic, magnetic, optical, and/or other types of storage media. Note that the memory can also have a distributed architecture, where various components are situated remotely from one another, but can be accessed by the processor. The software in the memory may include one or more separate programs, each of which includes an ordered listing of executable instructions for implementing logical functions. A system component embodied as software may also be construed as a source program, executable program (object code), script, or any other entity comprising a set of instructions to be performed. When constructed as a source program, the program is translated via a compiler, assembler, interpreter, or the like, which may or may not be included within the memory.

The aforementioned I/O devices that may be coupled to system I/O Interface(s) may include input devices, for example but not limited to, a keyboard, mouse, scanner, microphone, camera, proximity device, etc. Further, the I/O devices may also include output devices, for example but not limited to, a printer, display, etc. Finally, the I/O devices may further include devices that communicate both as inputs and outputs, for instance but not limited to, a modulator/demodulator (modem) for accessing another device, system, or network; a radio frequency (RF) or other transceiver; or a telephonic interface, bridge, router, etc. When the computing device is in operation, the processor can be configured to execute software stored within the memory, to communicate data to and from the memory, and to generally control operations of the computing device pursuant to the software. Software in memory, in whole or in part, is read by the processor, perhaps buffered within the processor, and then executed.

The afore described implementation of health monitoring lifecycle <NUM> is predicated on the accurate and continuous monitoring of many complex operating parameters for cold spray gun <NUM>. In other embodiments, a reduced set of operating parameters can be monitored. For example, in some embodiments, the monitoring of only the operating time and/or the number of start-up cycles of cold spray gun <NUM> can provide sufficiently accurate information from generate sample trigger step <NUM>.

Claim 1:
A method for monitoring a lifecycle of an additively manufactured cold spray gun (<NUM>), the additively manufactured cold spray gun (<NUM>) having a microcrystalline structure that can be subjected to a cyclic operational stress, using a health monitoring system (<NUM>) comprising a plurality of additively manufactured health monitoring coupons (<NUM>;<NUM>') disposed on the cold spray gun (<NUM>) in a representative position that is subjected to the cyclic operational stress, wherein the plurality of additively manufactured health monitoring coupons (<NUM>;<NUM>') are integrally manufactured with the cold spray gun (<NUM>) by means of a direct metal deposition DMD process such that the health monitoring coupons (<NUM>;<NUM>') are made of the same material and subject to the same material degradation as the cold spray gun (<NUM>), the method comprising:
monitoring one or more operational parameters of the additively manufactured cold spray gun (<NUM>),
wherein the one or more operational parameters of the additively manufactured cold spray gun (<NUM>) is selected from the group consisting of: number of startup cycles, operational time, operational temperature range, and operational pressure range;
calculating, based on the monitoring, a sample trigger;
removing, by a precision machining process, one of the additively manufactured health monitoring coupons (<NUM>;<NUM>') in response to the sample trigger;
analyzing, by an inspection process, the one of the additively manufactured health monitoring coupons (<NUM>;<NUM>');
determining whether the additively manufactured cold spray gun (<NUM>) is usable based on the analysis of the one of the additively manufactured health monitoring coupons (<NUM>;<NUM>');
resuming operating the additively manufactured cold spray gun (<NUM>) and continuing monitoring the one or more operational parameters if the additively manufactured cold spray gun (<NUM>) is usable; and
replacing the additively manufactured cold spray gun (<NUM>) if the additively manufactured cold spray gun (<NUM>) is not usable.