System and method for determining spray characteristics

Abstract

A system and method for determining spray characteristics of a powder or liquid spray is provided. The method includes: receiving spray characteristics of a powder or liquid spray; generating a spray map, including associating the received spray characteristics with spray application characteristics, operating parameters of the spray device, or both, the association being determined using calibration of scan measurements; and outputting a spray map. In particular cases, the method further includes adjusting operating parameters of the spray device to achieve particular performance of the spray application using the spray map.

Description

Technical Field

[0001] The following relates generally to powder or liquid spray devices; more particularly, to systems and methods for determining spray characteristics of a powder or liquid spray. Background Art

[0002] Nozzles have a wide range of applications, such as spray cooling systems, coating equipment, irrigation and pesticide applications in agriculture, and fuel injection systems in most engines. The spray formed by the nozzle is characterized by the size and spatial distribution of the droplets, which depends on the nozzle geometry, fluid properties, and operating settings such as fluid flow rate and pressure. For example, in an automotive painting application, the film thickness of the paint sprayed on the surface depends on the droplet size of the spray, the spray pattern or geometry (the number of droplets flying over a unit area per second), the overlap distance, the number of sprays, and the robot speed. The tolerance of the film thickness is very tight, as thick films may cause defects and unnecessary additional costs (due to increased paint usage). Summary of the invention

[0003] In one aspect, a processor-executable method for determining spray characteristics of a powder or liquid spray is provided, the method comprising: receiving spray characteristics of a powder or liquid spray; generating a spray map, comprising correlating the received spray characteristics with spray application characteristics, operating parameters of a spray device, or both, the correlation being determined using calibration of a scanning measurement; and outputting the spray map.

[0004] In certain aspects of the method, the method further comprises adjusting operating parameters of the spray device to achieve specific performance of the spray application using the spray pattern.

[0005] In another aspect of the method, the spray characteristics include one or more of: droplet size, droplet distribution, droplet velocity, and spray pattern or geometry.

[0006] In another aspect of the method, the operating parameters include one or more of: bell speed, flow rate, shaping air flow rate, and static charge.

[0007] In another aspect of the method, scanning measurements are performed at several different locations.

[0008] In another aspect of the method, the spray device moves in a radial direction, wherein generating the spray pattern includes determining a spatial position of each droplet on a spray radius based on a time at which a scan is performed using each capture.

[0009] In another aspect of the method, calibration includes varying one or more operating parameters and determining the effect on the spray characteristics using scanning measurements.

[0010] In another aspect of the method, a spray map is generated using a model to relate spray characteristics to operating parameters.

[0011] In another aspect of the method, generating the spray pattern includes correlating spray characteristics with changes in operating parameters and correlating changes in spray characteristics with spray application characteristics.

[0012] In another aspect of the method, the spray application characteristics include one or more of: color, film build, film appearance and quality, evaporation, powder morphology, and transfer efficiency.

[0013] In another aspect, a system for determining spray characteristics of a powder or liquid spray is provided, the system comprising one or more processors in communication with a data storage device to execute: a scanning module for receiving spray characteristics of a powder or liquid spray; and a mapping module for generating a spray map, including associating the received spray characteristics with spray application characteristics, operating parameters of the spray device, or both, the association being determined using calibration of the scanning measurement, and outputting the spray map.

[0014] In a particular case of the system, the system further comprises a regulating module for adjusting operating parameters of the spray device to achieve a particular performance of the spray application using the spray pattern.

[0015] In another aspect of the system, the spray characteristics include one or more of: droplet size, droplet distribution, droplet velocity, and spray pattern or geometry.

[0016] In another aspect of the system, the operating parameters include one or more of: a bell speed, a flow rate, a shaping air flow rate, and a static charge.

[0017] In another aspect of the system, scanning measurements are performed at several different locations.

[0018] In another aspect of the system, the spray device moves in a radial direction, wherein generating the spray pattern includes determining a spatial position of each droplet on a radius of the spray based on a time at which a scan is performed using each capture.

[0019] In another aspect of the system, calibration involves varying one or more operating parameters and determining the effect on the spray characteristics using scanning measurements.

[0020] In another aspect of the system, a spray map is generated using a model to relate spray characteristics to operating parameters.

[0021] In another aspect of the system, generating the spray map includes correlating spray characteristics with changes in operating parameters and correlating changes in spray characteristics with spray application characteristics.

[0022] In another aspect of the system, the spray application characteristics include one or more of: color, film build, film appearance and quality, evaporation, powder morphology, and transfer efficiency.

[0023] These and other aspects are considered and described herein.It should be understood that the foregoing summary lists representative aspects of the systems and methods to assist the skilled reader in understanding the detailed description that follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0025] Figure 1 is a schematic diagram of a system for determining spray characteristics of a powder or liquid spray according to an embodiment;

[0026] Figure 2 is a flow chart of a method for determining spray characteristics of a powder or liquid spray according to an embodiment;

[0027] Figure 3 is an example simplified path of an atomizer covering a planar surface during a series of spraying processes;

[0028] Figure 4 is a graph showing an example of variation in the liquid volume fraction of a spray captured during an experiment as a function of distance from the central axis;

[0029] Figure 5 is a graph showing examples of theoretical film thickness and experimental film thickness when an atomizer travels on a vertical surface;

[0030] Figure 6 is a graph of microns versus flop and cup speed to illustrate an example of how spray patterns can ensure paint applications meet specifications;

[0031] Figure 7 The relationship between the color vector ΔE and the Sauter mean diameter (D32) of the metallic coating is shown, which is the result of measuring the atomizer at various cup speeds in an example experiment;

[0032] Figure 8 is a schematic diagram of an imaging device for fast-moving particle characterization;

[0033] Fig. 9 is a schematic diagram of a lighting module;

[0034] Fig.10 is a perspective view of the shell;

[0035] Fig.11 yes Fig.10A perspective view of a front end member of a housing;

[0036] Fig.12 is a schematic diagram of the image analysis module;

[0037] Fig.13 is a flow chart of a fast moving particle characterization method according to an embodiment;

[0038] Fig.14 is a schematic diagram of an example optical isolator;

[0039] Fig.15 Various example trigger modes are shown;

[0040] Fig.16 A cross-sectional view showing an example of a camera probe;

[0041] Fig.17 A cross-sectional view showing an example of a laser probe;

[0042] Fig.18 is a graph showing experimental results for a spray consisting of a solid dissolved in a solvent, with normalized volume measured at several axial distances from the nozzle. DETAILED DESCRIPTION

[0043] Embodiments will now be described with reference to the accompanying drawings. For simplicity and clarity of description, reference numerals may be repeated in the figures to indicate corresponding or similar elements where deemed appropriate. In addition, in order to provide a thorough understanding of the embodiments described herein, many specific details are also described. However, it should be understood by those of ordinary skill in the art that the embodiments described herein may be implemented without these specific details. In other examples, in order not to obscure the embodiments described herein, known methods, procedures, and components have not yet been described in detail. In addition, this specific implementation should not be considered to limit the scope of the embodiments described herein.

[0044] Unless the context indicates otherwise, the various terms used in this specification can be read and understood as follows: "or" used in this specification is inclusive, just like "and / or"; singular articles and pronouns used in this specification include their plural forms and vice versa; similarly, gender pronouns include their counterparts, so the pronouns should not be understood as limiting anything described herein to use, implementation, performance, etc. by a single gender; "exemplary" should be understood as "illustrative" or "illustrative", not necessarily "preferred" over other embodiments. Further definitions of terms may be listed here; these may apply to previous and subsequent instances of these terms, which can be understood from reading this specification.

[0045] Any module, unit, component, server, computer, terminal, engine or device that executes instructions illustrated herein may include or otherwise access computer-readable media, such as storage media, computer storage media or data storage devices (removable and / or non-removable), such as disks, optical disks or tapes. Computer storage media may include volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information, such as computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include RAM, ROM, EEPROM, flash memory or other storage technology, CD-ROM, digital versatile disk (DVD) or other optical storage, cassettes, tapes, disk storage or other magnetic storage devices, or any other medium that can be used to store the required information and can be accessed by applications, modules or both. Any such computer storage medium may be part of a device, or may be accessed or connected to a device. In addition, unless the context clearly indicates otherwise, any processor or controller listed herein may be implemented as a single processor or multiple processors. Multiple processors may be arrayed or distributed, and any processing function mentioned herein may be performed by one or more processors, even if a single processor may be illustrated. Any methods, applications, or modules described herein may be implemented using computer-readable / executable instructions, which may be stored or otherwise maintained by such computer-readable media and executed by one or more processors.

[0046] The following relates generally to powder or liquid spray devices; more particularly, to systems and methods for determining spray characteristics of a powder or liquid spray.

[0047] While the present disclosure generally refers to the application of spraying coatings with a spray applicator, it will be appreciated that the present embodiments may be used with any suitable powder or liquid spray application, such as paint, evaporative cooling, combustion, and the like.

[0048] In an example application, a pharmaceutical spray consists of a liquid consisting of a solvent and dissolved solids. Ideally, the solvent evaporates during the spray drying process, leaving only spherical, monodisperse, hollow, porous particles. Particles form when the solid concentration at the surface of the droplets reaches a predetermined critical level. It is best for the solids to form a spherical shell that can maintain its structure, because the size and morphology of the particles will directly affect the performance of the spray-dried product. Current methods for predicting droplet size generally fail to capture the viscoelastic behavior of polymer spray solutions used in pharmaceutical applications. Advantageously, using the embodiments described herein, producing a droplet size distribution that results in optimal particle size and morphology can significantly improve production capacity and compound performance.

[0049] In a specific example, automotive paint is applied using an electrostatic rotary bell atomizer, which works by using centrifugal force to push a thin film of paint along the inner surface of a bell cup toward the rim, where it breaks up into a cloud of droplets as it is thrown out. Air jets and electrostatic forces are used to direct the paint onto the target surface. A robotic arm is used to position the paint atomizer. It can take three to five months of trial and error to determine which robotic path minimizes paint usage, cycle time, and material waste while depositing a thin film with acceptable uniformity. Some conventional efforts have been made to automate robotic paths by simulating the spray process to reduce the cost and time of bringing new cars to market.

[0050] Paint shops are perhaps the largest source of emissions of regulated chemicals (including about 35 g / m2 of volatile organic compounds, VOCs) and other air pollutants (about 0.5 tons of CO2 equivalent / unit) on the surface of the vehicle body; more than 80% of environmental issues in automotive assembly are related to the painting process. The cost of emission reduction equipment to capture these emissions and treat hazardous waste materials is very high. Despite this, the painting process is very inefficient. The transfer efficiency (i.e., the proportion of paint sprayed onto the surface) for car bodies is only about 40%, while small parts are as low as 10%. Improvements in transfer efficiency can significantly reduce emissions and energy use. Given these challenges, embodiments of the present disclosure can be advantageously used to reduce VOC emissions, improve transfer efficiency, and minimize rework of painted parts.

[0051] In some approaches, to determine the film thickness of paint sprayed by a nozzle, a regression model can be used to relate a test matrix of operating parameters to measured film builds; however, this is time consuming and expensive. In this case, the atomizer sprays on a "scanner" to measure the resulting film build. The limitation of this technique is that it cannot directly measure the spray in real time, so it may not capture the spray characteristics on a production line, etc.

[0052] In another common method, the transfer efficiency of the sprayed paint onto the surface being painted is determined by weighing the sample after spraying to calculate the amount of paint on the surface relative to the amount sprayed. In some cases, while adding static charge is intended to address this problem, this can cause the robot to short out and further atomize the liquid (very small droplets lack the momentum required to impact the surface).

[0053] The size of a paint droplet that strikes a surface affects the color and flip-flop (a measure of how brightness changes at different viewing angles) of the film. In some approaches, droplet size can be measured using laser-based devices that rely on reflection. However, metal flakes within a spinning paint droplet can interfere with this signal, making it difficult to accurately measure droplet size from a paint spray.

[0054] Many process inputs can cause variations in spray characteristics and damage the sprayed paint film. Attempting to control multiple process inputs (e.g., humidity, paint composition, temperature, downdraft velocity, etc.) is prone to error due to the compounding uncertainty of each parameter. In this embodiment, by determining the spray characteristics, e.g., droplet size and spray pattern or geometry, precise control parameters of the spray can be used.

[0055] In some current approaches, a trial-and-error process on the production line is used to determine whether a particular coating is sprayed wet (higher solvent content in the impinging droplets) or dry (lower solvent content).

[0056] There are multiple ways to measure particle size distribution using a variety of techniques. For example, there are diffraction-based methods, phase Doppler methods, and direct imaging methods. However, in general, previous direct imaging methods have only been able to operate in R&D environments and do not meet the full requirements for operating in hazardous locations. Due to the size of the laser system, high-speed camera, and optics, each of these components must be placed individually in the work environment. The camera and laser must then be aligned. Alignment is often a lengthy process that must be re-performed frequently because components can drift slightly over time, the location of the work being completed can move, or other equipment in the work environment can accidentally bump into the equipment.

[0057] Furthermore, other particle size determination methods often do not meet the minimum requirements for operation in hazardous locations and therefore cannot be operated in many industrial environments where sprays are used.

[0058] Additionally, current droplet measurement technology typically does not instruct users on how to relate droplet measurements to final color or paint quality (for example, in the automotive painting industry); this is often left to the user to discover. Furthermore, users do not have a framework or process for applying measurement data to solve their painting problems.

[0059] Other spray pattern or geometry measurement methods have instrumentation that provides information about the distribution of the spray in space. These methods do not typically provide droplet size information. While these methods may be helpful in estimating film thickness, they do not measure droplet size; therefore, they do not provide the user with any information about evaporation, color, or potential surface defects.

[0060] In general, current methods suffer from at least the following issues: inconsistent film thickness, low transfer efficiency, inconsistent color matching between parts, surface defects due to poor spray quality, and higher overall volatile organic compound and greenhouse gas emissions due to errors.

[0061] In some cases, an image of the liquid spraying from the rim of a cup can be used to qualitatively determine the quality of the spray (e.g., dirty cup, clogged saw teeth, etc.). While this can be a good estimate of the droplet size distribution, it is usually not a perfect representation of the actual droplet sizes that will impact the surface, nor is it a perfect representation of the spray pattern or geometry (which is important for industrial applications); there may be some spatial variation that affects film build. Additionally, this approach may have to contend with issues such as dirty cups, clogged saw teeth, etc.

[0062] This embodiment can advantageously use images captured radially at the tip-to-part distance to extract the spray pattern or geometry from the captured image. The relative frequency of droplets at different radial positions in the image can be used to obtain the spray pattern or geometry and generate a flux spray map of the spray; this can be done in real time on the production line.

[0063] In some cases, for each coating, a spray map can be determined that relates spray characteristics (such as droplet size and spray pattern or geometry) to color and film build layer and can be used to predict whether the paint finish and color are within the tolerance range specified by the manufacturer. In addition, if the quality of the spray is not enough, the present embodiment can be used to recommend corrective actions to the painter. Advantageously, these corrective actions can save a lot of time required for paint testing and reduce paint waste and emissions. Being able to continuously monitor spray characteristics such as droplet size and spray pattern or geometry on the assembly line enables the painter to ensure that the spray is in compliance with specifications; if the spray is not in compliance with specifications, they can perform preventive maintenance before defects occur.

[0064] The inventors have experimentally determined that spray characteristics, such as droplet size and spray pattern or geometry, provide accurate characterization of powder or liquid spray applications, such as film appearance and quality. Using the spray diagram and predictive model of the present embodiment to build a film means that the paint operator does not need to spend too much time trying to find the best operating parameters that can provide the color match required by the OEM or the speed and overlap required to match the film thickness. In general, even if the paint manufacturer provides recommended settings for the operating parameters of the atomizer, environmental factors (such as humidity and temperature) can also affect the coating, thereby deviating from the expected results. Advantageously, if the spray characteristics do not match the recommended specifications on the spray diagram, the spray operator can be notified. This can ensure that the coating (such as color) will not continue to be sprayed when it exceeds the specifications.

[0065] Although the present disclosure generally refers to spray applications, it will be appreciated by those skilled in the art that the determination of spray characteristics can be applied to any suitable application. In a non-limiting example, the system can also be applied to pharmaceutical applications where the spray characteristics (e.g., droplet size) directly affect the particle size; and particle size can be a critical process parameter.

[0066] In the case of automotive coatings applications, such coatings are solvent-based and consist primarily of solvents that evaporate during the spraying and film formation process. The rheology of the impacting droplet will determine how the paint film forms on the surface and, therefore, the color. However, understanding the rheology of the droplet at impact is not straightforward because the droplet evaporates during the transfer process and electrostatic charge accelerates this evaporation. An advantage of the system described so far is that it measures this evaporation rate (which is unique to each coating and is affected by environmental conditions). Feedback is provided to the spray operator if the droplet size is not within a given specification. By continuously understanding the droplet rheology, the paint operator will not have to use trial and error to determine whether a particular coating should be sprayed wet (higher film solvent content) or dry (lower solvent content). In addition, by ensuring that the droplet rheology at impact is within specification while maintaining film quality, solvent-based coatings with lower solvent content can be manufactured. This will reduce VOC emissions; a limiting parameter in automotive production.

[0067] Additionally, measuring the velocity of the droplets, which is a characteristic of the spray, provides the operator with the average time scale required for the droplets to reach the workpiece; therefore, the time scale required for evaporation. Fig.18 A graph showing the experimental results of the cumulative relative volumes of the spray consisting of solids dissolved in the solvent at several axial distances from the nozzle. The volumes are normalized by the volume at a distance of 50 mm. Fig.18 In the figure, it can be clearly seen that evaporation causes the relative volume of the spray to decrease gradually with increasing distance from the nozzle.

[0068] In various current methods, in order to determine the film thickness of a sprayed coating, an operator is required to spray a sample surface and then use appropriate equipment to measure the film build. This is time consuming, expensive, and only generates a single data point. In other current methods, an atomizer sprays the sample onto a "scanner" to measure the resulting film build. The present embodiment provides a fairly fast method of predicting the film thickness on a surface from a captured spray image without the need to spray onto a sample panel or surface; thereby avoiding waste. In addition, other information about the spray (e.g., film appearance and quality, color, degree of turnover, transfer efficiency, evaporation, film thickness) can be obtained from these images.

[0069] Figure 1Various physical and logical components of an embodiment of a system for determining spray characteristics of a powder or liquid spray 100 are shown. As shown, the system 100 has multiple physical and logical components, including a processing unit 102 (including one or more processors), a random access memory ("RAM") 104, a device interface 106, a user interface 108, a network interface 110, a non-volatile memory 112, and a local bus 114 for enabling the processing unit 102 to communicate with other components. The processing unit 102 can execute or instruct the execution of various modules, as described in more detail below. The RAM 104 provides relatively responsive volatile storage for the processing unit 102. The user interface 108 enables an administrator or user to provide input through an input device (e.g., a keyboard and a mouse) and provide information to an output device (e.g., a display). The device interface 106 can be used to communicate data with other devices (e.g., an imaging device 140 and / or an application device 142). The network interface 110 allows communication with other systems, such as other computing devices and servers that are remote from the system 100, such as a typical cloud-based access model. The non-volatile memory 112 stores the operating system and programs, including computer executable instructions for implementing the operating system and modules, and any data used by these services. As described below, additional stored data may be stored in the database 116. During operation of the system 100, the operating system, modules, and related data may be retrieved from the non-volatile memory 112 and loaded into the RAM 104 for execution.

[0070] System 100 includes one or more conceptual modules configured to be executed by processing unit 102. In one embodiment, the modules include scanning module 122, mapping module 124, adjustment module 126, and output module 128. In some cases, some modules may run at least in part on dedicated or separate hardware, while in other cases, at least some functionality of some modules is performed on processing unit 102.

[0071] The system 100 may be run on the computing device 26 and access content stored on the server through a network such as the Internet via the network interface 110. In further embodiments, the system 100 may be run only on the computing device or only on the server, or may be run and / or distributed on any other computing device; for example, a desktop computer, a laptop computer, a smartphone, a tablet computer, a server, a smart watch, a distributed or cloud computing device, etc. In some embodiments, the components of the system 100 are stored and executed on a single computer system. In other embodiments, the components of the system 100 are distributed between two or more computer systems that may be locally or remotely distributed.

[0072] For solvent-based coating applications, film thickness is tightly controlled because excessively thick film layers can cause surface tension-driven flow, which can lead to coating defects such as orange peel. Maintaining proper thickness requires balancing several parameters, such as:

[0073] The local droplet flow rate of the atomizer;

[0074] The speed of the atomizer;

[0075] the distance between each pass (overlap); and

[0076] The number of overlaps.

[0077] Figure 3 The schematic diagram shown illustrates an example simplified path of an ESRB atomizer covering a planar surface during a series of spraying passes.

[0078] The film profile on the surface is determined by the spray characteristics. Images can be continuously captured using imaging device 140 to capture the spray pattern or geometry; for example, from the central axis of the spray to its periphery. For this example, the relative abundance of droplets in the image is then used to determine the volume fraction as a function of radial position. Figure 4 An example of the relationship between the spray center axis distance and the liquid volume fraction captured in the experiment is shown.

[0079] In certain cases, assuming that the spray is isotropic, the system 100 can interpolate the pattern based on the atomizer tip speed and the liquid flow rate to generate a film thickness distribution.

[0080] Figure 5 An example of theoretical film thickness and experimental film thickness for an ESRB atomizer moving on a vertical surface at a speed (u) of 700 mm / s is shown. Experiments have shown that the model is in good agreement with the experimental results. System 100 is able to identify areas where the film thickness varies significantly and make recommendations when the overlap distance is too large. In some cases, a larger overlap distance typically results in an uneven film layer. In certain cases, the optimal overlap distance can be determined by drawing a horizontal regression line of the maximum value of the film thickness distribution. In general, if the standard deviation of the maximum value relative to the regression line is large, it indicates that the film is wavy and uneven.

[0081] Generally speaking, not all droplets have the momentum required to impact a surface. Droplets with diameters below the penetration threshold will not penetrate the boundary layer and will not contribute to film formation. The ratio of droplet volume that impacts the surface to the total volume of droplets is defined as transfer efficiency. The transfer efficiency of a spray is often varied based on specific operating parameter values ​​while also ensuring color matching. Improving transfer efficiency can reduce the amount of paint used, thereby reducing costs and reducing VOC emissions.

[0082] In some cases, the theoretical film build can be determined by assuming that droplets with diameters smaller than a predetermined critical diameter lack sufficient momentum to reach the surface. If the diameter threshold is low (i.e., only droplets smaller than, for example, 5 microns fail to impact), the film will be thicker as more droplets reach the surface, whereas if the diameter threshold is high (i.e., droplets smaller than, for example, 20 microns fail to impact), the film will be thinner and smaller droplets will eventually enter the overspray. By definition, the ratio of the volume of droplets above the critical diameter to the total number of droplets is the transfer efficiency.

[0083] The appearance of the sprayed coating film, including its color, depends not only on the pigment of the coating, but also on the spray characteristics and film buildability. Unfortunately, many factors may affect the final color of the coating; for example, the rotating speed of the bell, the static charge of the bell, temperature, humidity, etc. By determining the selected process parameters, the system 100 can determine the control parameters of the spray system, and in certain cases, the system 100 determines the spray characteristics of the droplet size and spray pattern or geometry.

[0084] The color of a paint film is often directly related to the spray characteristics, such as droplet size. One particular metric that needs to be monitored is flop, which is the change in brightness of a paint film when viewed from different angles. In one example, the color on a painted panel can be measured and then the system can receive these measurements. The received measurements can be combined with measurements of the spray characteristics to generate a spray map, as described in this article. The spray map models the flop based on the spray characteristics. The equation for flop is based on brightness values ​​measured at a specific angle relative to specular reflection, for example:

[0085]

[0086] The aluminum flakes contained in many metallic paints act as tiny mirrors, reflecting light back. The brightness caused by this reflection is greatest when viewed at the reflected angle (based on the angle of incidence). However, the orientation of the flakes in a thick film may not always be the same in several coats of paint.

[0087] In an example, regression analysis can be used to correlate droplet size with color. Figure 6 An example of how spray mapping can ensure that paint applications are within specifications is illustrated. For this example, a single independent variable is considered (the cup speed is set to 46RPM) and the degree of overturn is specified to be greater than 12. The average droplet size is represented by D32, but paint mapping is not limited to the use of this statistic. In an application environment (such as a production line), rather than spraying a part to check that the spray produces the desired color (which is typical practice today), the operator can measure the spray and analyze the results using the present system. Using such measurements, a spray pattern can be determined to recommend changes to operating parameters in order to, for example, stay within specifications. In Figure 6 In the example of , it is recommended to increase the cup speed by 5% to reduce D32 from 20.6μm to 20.3μm to ensure that the rollover is within tolerance (i.e. greater than 12).

[0088] Another metric to monitor is the color vector (ΔE) based on the brightness, hue, and chromaticity measurements received by the system. The equation for the color vector is:

[0089]

[0090] Figure 7 ΔE versus Sauter mean diameter (D32) for metallic paint measured in example experiments with an atomizer operating at various cup speeds is shown. The shaded background covers ΔE values ​​greater than 1.5, as this is close to the level discernible by the human eye. There is a clear correlation between ΔE and Sauter mean diameter. Increasing or decreasing the droplet size from 20.2 μm results in a change in color. This color change is observable to a human observer when the Sauter mean diameter changes slightly below about 0.4 μm.

[0091] Figure 2 A flow chart of a method for determining spray characteristics of a powder or liquid spray according to an embodiment is shown. For ease of illustration, method 200 is described for determining film thickness on a simple plane; however, those skilled in the art will appreciate that method 200 can be applied to more complex surfaces.

[0092] At block 202, the scanning module 122 performs a scan through the imaging device 140 to determine the measured values ​​of the spray characteristics under various operating parameters of a given paint and spraying equipment combination, such as droplet size, droplet distribution, droplet velocity and / or spray pattern or geometry. In other cases, the scanning module 122 can receive scanning measurements from the database 116, the network interface 110, or the user interface 108. The operating parameters may include, for example, a rotating cup speed, a liquid or powder flow rate, a forming airflow rate, and static charge. The scanning measurement may refer to measurements taken at several positions, for example, at several radial positions at a certain axial distance from the application device 142 (e.g., a rotating cup or nozzle or nozzle sprayer of an ESRB atomizer). In the example of a rotating cup, the rotating cup can move radially at a certain speed, and the imaging device 140 captures images at a certain frame rate to generate scanning measurements.

[0093] At block 204, the scanning module 122 can process the captured image / scan so that each measured droplet diameter can be associated with a spatial location. In some cases, this can be performed on the production line to ensure that the spray meets specifications in real time.

[0094] In order to obtain the spatial position of each droplet in the spray, a scanning measurement can be performed. In a specific method, the atomizer can be moved towards the device; wherein the first image is the periphery of the spray and the last image is the center of the spray. In this case, the atomizer is located at a certain axial distance above the device (upstream). The scanning width can be received, i.e. the distance from the initial position at the periphery to the center, and since the time of each captured image is known, the position of each droplet can be determined based on the spray radius.

[0095] At block 206, the mapping module 124 generates a spray map using the scan measurements. The spray map includes a set of data sets including correlations between measured droplet size and spray pattern or geometry and spray application characteristics (e.g., color, dynamics, film buildability, film appearance and quality, evaporation, powder morphology, and transfer efficiency). The spray map can be used to ensure that each sprayed paint spray meets given specifications. For example, before a large amount of paint is used on a production line, a spray map can be determined. The spray map is typically unique for each coating and associates droplet size and spray pattern or geometry with color information for different operating parameters of the spray device 142. Operating parameters can include, for example, cup speed, liquid flow rate, forming air flow rate, and static charge.

[0096] The correlation of the spray pattern can be determined by calibration; for example, using a half-factor experiment. During such a calibration process, one or more operating parameters can be varied, and the relevant effects (i.e., correlations) on droplet size and spray pattern or geometry can be determined using the received scanning measurements. In this way, scanning measurements of droplet size and / or spray pattern or geometry are obtained, allowing the system 100 to determine the flux of the spray, and then store a correlation mapping of the scanning measurements to the characteristics of the spray applied to the surface (such as film thickness and coverage). In addition, knowing the correlation between the scanning measurements and the operating parameters allows the system 100 to map how changes in the operating parameters affect droplet size and spray pattern or geometry, thereby making a very accurate interpolation of the effects of these parameters on the ultimate spray deposition on the surface.

[0097] Spray maps can be calibrated using experiments (e.g., box-behnken) to capture changes in key process parameters that occur when operating parameters are changed. Color, film build, film appearance and quality, evaporation, powder morphology, and / or transfer efficiency are often related to droplet size and spray pattern or geometry; which in turn are often related to operating parameters. An example method to relate all of these parameters is to use multivariate analysis, where a new coating map can be created for each coating.

[0098] In certain cases, the data structure for each spray map will consist of coefficients relating the effects of operating parameters to spray characteristics (droplet size, droplet distribution, droplet velocity, and spray pattern or geometry). One way to model the effects of operating parameters is to use a regression model:

[0099]

[0100] Where Y represents an output, such as D32; β0 and β i are regression coefficients; X are the manipulated parameters. This system of linear equations can be solved based on the number of trials used in the experiment. While the above is a regression model, other models can be used to capture interactions or higher-order trends between manipulated parameters; for example, other machine learning or artificial intelligence models.

[0101] In some cases, spray application characteristics (e.g., color, film build, film appearance and quality, evaporation, powder morphology, and / or transfer efficiency) can be identified and correlated to the spray characteristics (rather than to the corresponding operating parameters). This can be done to avoid being affected by changes in process parameters; such as differences in environmental factors (e.g., humidity, temperature, etc.) between a coating manufacturer's facility and the coating application environment (e.g., an automotive production line). In this case, the operating parameters (e.g., cup speed, fluid flow rate, etc.) will be directly related to the spray characteristics; the spray characteristics can then be correlated to the application characteristics (e.g., color, film build, evaporation, transfer efficiency, etc.). For example, the impact on paint color can be correlated to changes in spray characteristics (e.g., droplet size, droplet distribution, droplet velocity, and spray pattern or geometry). In the application environment, a calibration procedure can be used to generate the optimal spray characteristics to inform the user how to adjust the spray to stay within specifications.

[0102] In the example, an operator can indicate the spray characteristics that result in optimal color and film build when creating a paint map. Because the spray map captures the effects of each operating parameter in the experiment specified by the experimental design, the system can recommend corrective actions if external parameters affect spray characteristics (such as temperature, an important concern between warm and cold seasons). For example, higher temperatures will result in greater evaporation and smaller than optimal droplet size. Back Figure 6 Using the example of cup speed, the system can use the spray map to, for example, suggest reducing the cup speed by a specific percentage to increase the droplet size.

[0103] Advantageously, the present embodiment provides a method in which color, film build, and transfer efficiency are functions of spray characteristics (e.g., droplet size, droplet distribution, droplet velocity, and / or spray pattern or geometry). When developing a spray map, correlations can be determined for how droplet size changes as a result of changes in specific operating parameters, and then correlations can be determined for how these changing parameters affect color, film build, and transfer efficiency.

[0104] The spray pattern data may be compiled into database 116, and system 100 may use such spray patterns during production.

[0105] In some cases, at block 208, the adjustment module 126 may reference the spray map to determine various adjustments to operating parameters by comparing the paint film application to a given specification. For example, if the droplet size is smaller than the size recommended by the specification, the paint color will be lighter than expected, suggesting that the droplet size can be increased by reducing the cup speed. Advantageously, because the system 100 can use the precise correlations stored in the spray map, changes in environmental conditions, such as temperature and humidity (which can greatly affect spray characteristics) can be taken into account and quickly corrected using live scan measurements of the spray.

[0106] Generally speaking, the specifications for color and film build are set by the respective paint manufacturers. During the creation of a spray map, the operator can enter the specifications and tolerances. The spray map relates the specifications and tolerances (e.g., color, film build, and transfer efficiency) to the spray characteristics.

[0107] In some cases, spray mapping can include multiple levels of optimization based on user input. For example, if the operator specifies certain tolerances for film thickness and color, the spray mapping can be used to determine the best parameters to maximize transfer efficiency while ensuring that color and film thickness are within specification tolerances.

[0108] At block 210, the output module 128 may output the spray pattern and / or recommendations to the user interface 108, the network interface 110, and / or the database 116. In some cases, the output module 128 may output recommendations to the device interface 106 to instruct the application device to modify one or more operating parameters as determined in block 208.

[0109] Advantageously, the inventors have determined that droplet size and spray pattern or geometry can be accurately correlated to spray deposition; rather than trying to roughly estimate spray deposition based on application parameters (e.g., from the cup speed). This increased accuracy can save significant costs and increase efficiency when implemented in practice.

[0110] In the example of this embodiment for pharmaceutical applications, the spray characteristics can be controlled by adjusting specific operating parameters; for example, liquid feed rate, concentration, or viscosity. By monitoring the effect of different combinations of these process parameters on the spray characteristics, a response graph can be generated using methods such as regression analysis. The spray graph can take each operating parameter into account and be used to recommend to the operator or automatic controller how to adjust the parameters to keep the particle size, which is a key process parameter, within the specification range.

[0111] An example of mapping operating parameters is to relate the distance from the nozzle to the spray pattern or geometry (i.e., the relative volume of the spray); thereby determining the evaporation rate. The evaporation rate is the rate at which the volume is reduced due to the formation of a shell of solids on the surface of the droplets, which hinders the diffusion of solvent to the outer surface. After creating a spray map using the system 100, for example, regression analysis can be used to recommend an optimal distance from the nozzle at which the droplet size does not change, indicating the completion of particle formation.

[0112] In particularly favorable circumstances, such as Figure 8 As shown, the imaging device 140 may include a device for fast moving particle characterization so that droplet size and spray pattern or geometry can be characterized in real time. The device 140 may include an illumination module 402, a camera module 404, and an image analysis module 406. These modules may be interconnected or communicated in any suitable manner. In some cases, the device 140 also includes a housing 408 for accommodating the camera module 404 and the illumination module 402, and in some cases, the image analysis module 406. In other cases, the image analysis module 406 may be remote from the housing 408.

[0113] Although the following disclosure describes the functions and operations of illumination module 402 , camera module 404 , and image analysis module 406 as being performed on device 140 , it will be appreciated that one or more of these operations and functions may be performed by system 100 .

[0114] Fig. 9An example embodiment of an illumination module 402 is shown, which includes a light source 410 (e.g., a stacked semiconductor laser diode array, a light emitting diode (LED), a near infrared (NIR) semiconductor laser diode, etc.), a pulse generator 412 (also known as a current amplifier or function generator), a synchronization board 418, and optical elements 420 for adjusting the light beam. In one embodiment, a semiconductor laser diode array can be used as the light source 410 because it is bright and compact. In some cases, the light source 410 will include an appropriate driver, such as a laser driver for a laser diode array. In most cases, since a short nanosecond flash is required to freeze the motion of the particle, the light intensity must be increased to a high enough position to properly illuminate the particle. If the nominal light intensity value of a typical laser diode is used, it may not provide enough light energy to capture an image on a camera sensor due to its short duration. Therefore, for these short duration flashes, the light power must be very high. To achieve this, the illumination module 402 includes a pulse generator 412, which can provide current to achieve a high intensity nanosecond flash. For example, the laser pulse energy can be on the order of 65uJ, while the flash can be on the order of 10ns-100ns.

[0115] Advantageously, illumination module 402 can use a high-powered near-infrared laser diode or LED, rather than a low-powered visible wavelength laser. Advantageously, near-infrared lasers can be more compact than visible spectrum lasers of the same power. There is an inverse relationship between laser power and wavelength. While most other methods use visible wavelengths, illumination module 402 can use near-infrared laser diodes to achieve similar brightness on the captured image, whose light can better penetrate the spray.

[0116] The light produced by the light source 410 may be a combination of beams from individual diodes or LEDs. For imaging, the beam may be adjusted to a uniform flat top profile of incoherent or semi-coherent light by using an optical element 420. In most cases, the beam should be flat top so that certain parts of the image are not magnified, allowing for more accurate image analysis. A uniform flat top profile generally means that all areas of the laser have the same brightness. Most lasers are naturally brighter at the center of the beam and then get dimmer as the distance from the center increases. This characteristic is disadvantageous for imaging because uniform illumination is required in every part of the image. If some part is illuminated brighter, then it may be overexposed, causing that part to be overexposed and data to be lost; or if the magnified part is at the correct exposure level, then other parts of the image may be underexposed and data may be lost. Optical elements may be used to produce a laser beam that has the same or similar brightness throughout the laser beam; that is, the profile of the laser is said to be "flat."

[0117] The light beam is typically formed from incoherent or semi-coherent light because coherent light typically forms a distinct diffraction pattern around objects in the image plane, making image analysis more difficult. In the example of optical element 420, the light beam can be homogenized and decohered by first passing through a homogenizing light rod. The light beam can then pass through a diffuser to further decoherent the light. The light beam can then pass through a device to collimate the light, such as an aspheric double lens. In other cases, microlens arrays, liquid light guides, and fiber optic cables can be used. It will be appreciated that any suitable method can be used to reduce the coherence of the light.

[0118] The light source 410 can be driven by a pulse generator 412, which receives a trigger signal from a synchronization board 418. The pulse generator 412 can generate a high voltage and / or high current pulse of a specific duration; for example, as low as one nanosecond. The duration of the light pulse and the parameters of the voltage and current can be controlled using the pulse generator 412, which can receive a trigger signal from the synchronization board 418. The trigger signal is typically generated by the camera module 404 and then passed to the synchronization board 418 to compensate for any noise between the camera module 404 output and the lighting module 402. The trigger signal can be an electrical pulse emitted by the camera to trigger the light source 410 to operate and illuminate the field of view. In most cases, the trigger signal can be automatically generated by the camera immediately before the camera is set to capture an image.

[0119] The camera of the camera module 404 outputs a synchronization signal, which may be noisy. In some cases, due to this noise, if the synchronization signal is sent directly to the pulse generator 412, it may cause the light source 410 to trigger erroneously. To avoid this problem, a synchronization board 418 may be used between the camera module 404 and the pulse generator 412. In some cases, the synchronization board 412 can accurately detect the camera signal from the background noise and output a noise-reduced signal to the pulse generator 412. The synchronization board 418 may use any suitable noise reduction algorithm.

[0120] Once the pulse generator 412 receives the trigger signal from the synchronization board 418, the pulse generator 412 then sends a pulse (in most cases, a high voltage, high current pulse) to the light source 410, which is then converted into light. The connection from the pulse generator 412 to the light source 410 is typically of very low inductance. In many cases, in order to transfer maximum energy to the light source 410, the pulse generator 412 can be located close to the light source 410.

[0121] Generally, for other methods, the magnification of the objective lens varies with the distance of the captured object. This makes it difficult for the user to calibrate particles and droplets that are randomly distributed in space. To eliminate the need for this focus and calibration, the camera module 404 can use a telecentric lens. A telecentric lens only accepts light perpendicular to the lens surface, so any object in the field of view remains the same size at any distance within the depth of field. The inventors conducted example tests to determine the appropriate combination of (i) camera resolution and pixel size and (ii) a telecentric lens with appropriate magnification, focal length, and depth of field to capture particles as small as 5μm. This is capable of measuring particles below 5 microns required for use in hazardous locations. In the test, the resolution ranged from 6 to 18MPix, the pixel size ranged from 0.9um to 3um, the magnification ranged from 0.5x to 3x, and the focal plane distance (working distance) ranged from 100mm to 400mm.

[0122] In some cases, the optical power output can be limited to meet hazardous location (HazLoc) requirements. In this case, the optical power can be reduced to less than 85uJ per pulse to ensure the intrinsic safety of the light source 410. Advantageously, the camera and lens combination of the camera module 404 can still have high sensitivity to low light / power when using a high transmittance, low magnification telecentric lens; and using a camera with physically small pixels to compensate for the low magnification lens. This arrangement of the camera module 404 allows the lighting module 402 to use a small, low-power laser. Advantageously, lenses of different magnifications can be used at the same working distance without changing the measurement position. Lenses with lower magnifications are typically physically smaller, making such lenses more compact than other options.

[0123] The housing 408 can advantageously house all optical and electronic components. In this way, the user generally does not need to worry about finding the correct settings, as the position of the lighting module 402 and the camera module 404 is fixed, thereby simplifying the measurement process. The housing 408 can also effectively protect the components from the mist or any other environmental conditions in the spray environment. This feature is particularly important because the housing will usually be placed on the production line and sometimes even in the spray or particle flow. In this environment, the housing 408 can effectively protect the components from moisture. The housing 408 also isolates the components inside the housing 408 from the external environment. In some cases, it can be operated in a spray environment, such as a hazardous location or an industrial location, where there may be a very high risk of explosion due to the chemical composition of the particles. If a spark or a small explosion occurs inside the housing, it must be ensured that it will not cause further ignition or explosion in the spray environment.

[0124] Advantageously, lighting module 402 allows for a smaller housing 408 and minimizes the overall size of device 140 . Fig.10 An example embodiment of a housing 408 is shown. In this example, the illumination probe 454 of the housing 408 (including the illumination module 402) can be a cylinder. In this example, the camera probe 452 of the housing 408 (including the camera module 404) can also be a cylinder. The imaging portion 456 of the housing 408 includes at least the image analysis module 406, which can be connected to the camera probe 452 and the illumination probe 454. The housing 408 can include a conduit for accommodating a communication channel for communication between the components. It will be appreciated that in other examples, any suitable housing and probe arrangement can be used. In this example, the housing 408 is made of stainless steel; however, in further examples, it can be any other suitable material, such as aluminum.

[0125] Fig.16 A cross-sectional view of an example of a camera probe 452 is shown, Fig.17 A cross-sectional view of an example of a laser probe 454 is shown. In some cases, the illumination probe 454 and the camera probe 452 can each have a front window that forms a dust and liquid proof housing. In some cases, a purge plate can be placed in front of the camera probe 452 window to prevent particles and debris from accumulating on the window.

[0126] In this example, the camera probe 452 includes a front cover 602 with a purge inlet 604, a lens assembly 606, and a camera 608. In this example, the laser probe 454 includes a front cover 702 with a purge inlet 704, a collimating optic 706, a homogenizing optic 708, a laser 710, a synchronization board 712, and a pulse generator 714.

[0127] The probe can be made of any suitable material; for example, aluminum, and a quartz disk for the window. The glass of the window can be compressed between the internal retaining ring and the probe body. Two O-rings can be used to seal each window. One is placed in a groove and compressed on the probe body, and the other is placed in a groove in the window and compressed around the quartz glass. The threaded holes in the window body and the clearing holes in the probe body can be used; for example, one of the holes delivers compressed air to the window piece, thereby forming an air curtain to prevent droplets from the glass surface and keep the viewing area clear.

[0128] Fig.12A schematic diagram of an example embodiment of an image analysis module 406 is shown. In this embodiment, the image analysis module 406 may include a number of physical and logical components, including a processing unit ("PU") 460, a random access memory ("RAM") 464, an input / output (I / O) interface 472, a data store 480, and a local bus 484 that enables the PU 460 to communicate with other components. The PU 460 may include one or more processors; for example, in a central processing unit or a graphics processing unit. The RAM 464 provides relatively responsive volatile storage for the PU 460. The I / O interface 472 enables a user to provide input through, for example, a keyboard and mouse. The I / O interface 472 can also output information to an output device, such as a display or speaker. The I / O interface 472 can also allow communication with other modules and / or other systems or computing devices. The data store 480 stores an operating system and programs, including computer executable instructions for image analysis, and any derivative or related processes. During operation, the operating system, programs, and data can be retrieved from the data store 480 and loaded into the RAM 464 for execution. In an embodiment, the PU 460 may be configured to execute various conceptual submodules, such as a triggering submodule 490 and an analysis submodule 492. In further embodiments, the functionality of the image analysis module 406 may be executed on dedicated hardware or a specific microprocessor, as appropriate. In some cases, the I / O interface 472 may include a user interface; for example, through a web browser or cloud computing interface, which may allow for easier integration with existing systems.

[0129] The image analysis module 106 may perform a variety of operations; for example, for paint sprays:

[0130] Perform statistics and visualize results to compare various nozzles by:

[0131] Bring the nozzle into the camera's field of view,

[0132] Capturing images of droplets from a spray,

[0133] Determine statistics about droplet size distribution in real time,

[0134] Collect more data from as many different nozzles or sprays as needed, and

[0135] Store data for comparison in post-processing.

[0136] Make sure the nozzle is not damaged,

[0137] Verify spray between cleaning cycles and / or paint color changes to ensure spray characteristics remain constant compared to paint / nozzle manufacturer’s recommendations or facility specifications,

[0138] Prevent improper spraying by ensuring spray consistency before spraying, and

[0139] Ensure spray characteristics remain constant compared to paint / nozzle manufacturer recommendations or facility specifications by measuring droplet size characteristics and statistics as described above, ensuring these statistics do not exceed a certain tolerance range over time.

[0140] Reference now Fig.13 , which shows a method 500 for fast moving particle characterization according to an embodiment. The method 500 can be performed when at least a portion of the spray is located between the illumination probe 454 and the camera probe 452.

[0141] At block 502 , the trigger submodule 490 or the camera module 404 sends a trigger to the lighting module 402 using, for example, a time-to-live (TTL) trigger output signal.

[0142] At block 504 , the illumination module 402 generates a pulsed output, such as laser pulses.

[0143] At block 506, the camera module 404 captures an image on the image sensor. In some cases, such an image may be a shadow map image of particles located between the illumination module 402 and the camera module 404.

[0144] At block 508 , the analysis submodule 492 receives the captured image from the camera module 404 .

[0145] At block 510, the analysis submodule 492 determines properties of the particles detected in the captured images, such as size and / or morphology, and in some cases, determines statistics based on these properties. Various suitable statistics can be determined from the particle characteristics, such as mean, standard deviation, Sauter mean diameter, minimum size, maximum size, numerical percentile, volume percentile, span, etc.

[0146] At block 512, the analysis submodule 492 outputs the analysis. For example, the features, size distribution, and statistics of the shadow map image are output to the data store 480 or to a display or other computing device via the I / O interface 472.

[0147] In an exemplary embodiment, the camera module 504 includes an image sensor, an optocoupler trigger, a flash as a light source, and two general purpose input / output (GPIO) ports. Fig.14The schematic diagram in shows how an opto-isolator can be used to electrically isolate the flash output to protect the camera module 104 and the image analysis module 406 from electrical surges. The output of the opto-isolator can be used as an open collector or open emitter output; this means that the output signal can be connected to ground or a supply voltage. The camera exposure can be synchronized with the light source 410 so that the image sensor can record an image. The image formed can be a shadow map of the particles in the field of view of the image sensor. The shadows produced by the shadow map are used to identify the morphology of the particles. The morphology can be any geometric information about the particle; including diameter, circumference, area, aspect ratio, eccentricity, etc.

[0148] Shadowgraphy is a technique that generates and analyzes the shadow of an object rather than the object itself. In shadowgraphy, the light source 410 is located behind the object being imaged, so the object blocks light from entering the camera and produces a shadow (a darker area) on the camera sensor. The geometry of the shadow is exactly the same as the object itself, so the shape of the object can be determined by detecting and analyzing the shadow in the image.

[0149] In most cases, the image analysis module 406 can take into account various factors; for example, (i) whether the droplets and particles are in focus or out of focus, and how to identify and correct such effects; (ii) how the droplet or particle motion affects the image quality and measurement; and (iii) the accuracy of the particle edge definition. In addition, the image analysis module 406 can automatically perform image acquisition, image processing, and user interface and data logging. The images captured by the camera module 404 can be processed in real time by the image analysis module 406, or stored in the data storage 480 and processed later.

[0150] The parameters of the flash output of the camera module 104 can be set by the user. In some cases, the flash output can have two modes, high active and low active. In the high active mode, the digital output is set to "High" during the exposure; in the low active mode, the digital output is set to "Low" during the exposure. Flash delay sets the delay of the digital output. After the exposure starts, the digital output will be activated according to the time delay set by the flash delay. Duration sets the triggering time of the digital output. The digital output remains active for the time set in the duration.

[0151] To capture high contrast images of particle ejection, in one example, a flash lamp (e.g., an array of light emitting diodes (LEDs)) can be triggered for a few hundred nanoseconds. Due to the short exposure time, very high illumination intensity is usually required. For example, the flash lamp can contain a high power green LED (PT-120LED, operating current of 30A, voltage of 5.9V, and maximum drivable flux of 5200). For example, an LED driver module can be used that allows high current (up to 240A) and voltage (up to 100V) pulses to be applied to the LED. The LED driver produces pulse widths of 60ns to 1μs. The pulse width can be determined by the trigger input signal.

[0152] In some cases, the input signal of the LED driver may not be triggered by the flash output signal of the camera module 404, because the maximum pulse width that the camera module 404 can generate is usually only 40 μs. To achieve short control pulses, a programmable version of the pulse generator 412 can be used.

[0153] For example, the pulse generator 412 may have four trigger modes, such as Fig.15 as shown; however, any suitable number or suitable trigger type may be used. The correct position of the flash can be determined by selecting the appropriate trigger mode. Trigger modes 1 and 4 (Trgmode 1 and Trgmode 4) can be used when the camera module 104 flash output signal is set to a high level. Trigger modes 0 and 5 (Trgmode 0 and Trgmode 5) can be used when the camera module 404 flash output signal is set to a low level. The number of pulses generated can be determined by the user through the shots syntax.

[0154] When the pulse generator 412 is connected to the LED driver, the voltage mode can be activated by default and used for calibration to change the mode to current mode. Umin is the minimum value of the voltage (slightly above the threshold voltage of the diode, for example 12V), and overcurrent is the maximum diode current used for calibration. If an error occurs during the calibration process, it indicates that Umin needs to be increased. When the LED is replaced, calibration can be performed again because the pulse generator cannot detect this change. When the calibration is completed, the mode can be automatically changed to current mode. After adjusting the current, voltage, repetition rate, trigger mode, and number of pulses (shots) using the appropriate syntax, the laser diode 110 can be turned on in current mode.

[0155] Advantageously, the device 140 can measure particle sizes as small as, for example, 5 microns. In an example, a pulse duration of 10-100 nanoseconds can be generated. For example, the light wavelength is 532nm or 905nm, but can be changed according to each specific application. Depending on the optical elements, for example, the depth of field can range from 50μm to 1mm.

[0156] Advantageously, the device 140 may provide a modular design that allows it to be used in a variety of environments and industries. The system 100 allows certain components to be easily interchanged for different applications without changing the functionality or operating principles of the device 140. For example, the camera may be changed to obtain a higher or lower resolution or a higher or lower pixel size, or the lens may be changed to obtain a higher or lower magnification.

[0157] Although the present invention has been described with reference to certain specific embodiments, it will be apparent to those skilled in the art that various modifications may be made without departing from the spirit and scope of the present invention as defined in the appended claims. The entire disclosures of all the above references are incorporated herein by reference.

Claims

1. A processor-executable method for determining spray characteristics of a powder or liquid spray, the method comprising: receiving spray characteristics of powder or liquid spray; generating a spray map, including correlating the received spray characteristics with spray application characteristics, operating parameters of the spray device, or both, the correlation being determined using calibration of the scan measurements; and Output the spray map.

2. The method of claim 1, further comprising adjusting operating parameters of a spray device to achieve specific performance of a spray application using the spray pattern.

3. The method of claim 1, wherein the spray characteristics include one or more of: droplet size, droplet distribution, droplet velocity, and spray pattern or geometry. 4 . The method of claim 1 , wherein the operating parameters include one or more of: bell speed, flow rate, shaping airflow rate, and static charge. The method according to claim 1 , wherein the scanning measurement is performed at several different locations.

6. The method of claim 5, wherein the spray device moves in a radial direction, and wherein generating the spray pattern comprises determining the spatial position of each droplet on the spray radius based on the time at which a scan is performed using each capture.

7. The method of claim 1, wherein the calibration comprises varying one or more operating parameters and determining the effect on the spray characteristics using scanning measurements.

8. The method of claim 1, wherein the spray map is generated using a model to relate spray characteristics to operating parameters.

9. The method of claim 1, wherein generating the spray pattern comprises correlating spray characteristics with changes in operating parameters and correlating changes in spray characteristics with spray application characteristics.

10. The method of claim 1, wherein the spray application characteristics include one or more of: color, film build, film appearance and quality, evaporation, powder morphology, and transfer efficiency.

11. A system for determining spray characteristics of a powder or liquid spray, the system comprising one or more processors in communication with a data store to perform: a scanning module for receiving spray characteristics of a powder or liquid spray; and A mapping module for generating a spray pattern includes correlating received spray characteristics with spray application characteristics, operating parameters of the spray device, or both, the correlation being determined using calibration of the scan measurements, and outputting the spray pattern.

12. The system of claim 11, further comprising an adjustment module for adjusting operating parameters of the spray device to achieve specific performance of the spray application using the spray pattern.

13. The system of claim 11, wherein the spray characteristics include one or more of: droplet size, droplet distribution, droplet velocity, and spray pattern or geometry.

14. The system of claim 11, wherein the operating parameters include one or more of: bell speed, flow rate, shaping air flow rate, and static charge.

15. The system of claim 11, wherein the scanning measurements are performed at several different locations.

16. The system of claim 15, wherein the spray device moves in a radial direction, and wherein generating the spray pattern includes determining the spatial position of each droplet on the spray radius based on the time at which the scan is performed using each capture.

17. The system of claim 11, wherein the calibration includes varying one or more operating parameters and determining the effect on spray characteristics using scanning measurements.

18. The system of claim 11, wherein the spray map is generated using a model to relate spray characteristics to operating parameters.

19. The system of claim 11, wherein generating the spray map comprises correlating spray characteristics with changes in operating parameters and correlating changes in spray characteristics with spray application characteristics.

20. The system of claim 11, wherein the spray application characteristics include one or more of: color, film build, film appearance and quality, evaporation, powder morphology, and transfer efficiency.

Images