PORTABLE LASER SYSTEM.

Abstract

A portable laser system. In certain examples, the portable laser system includes a laser source that emits laser light at a wavelength to perform a material processing operation on a workpiece material with a laser beam of the emitted laser light, a plasma sensor configured to detect plasma emitted from the workpiece material during a material processing operation, and a controller coupled to the plasma sensor and configured to: compare an optical intensity value obtained by the plasma sensor with a threshold value at a time when a predetermined period of time has elapsed after the material processing operation has begun, and produce a control command based on the comparison.

Description

PORTABLE LASER SYSTEM REFERENCE TO PREVIOUS APPLICATIONS This application claims the benefit of United States Provisional Patent Application No. 63 / 069,816 filed on August 25, 2020, and United States Provisional Patent Application No. 63 / 089,113 filed on October 8, 2020, each of which is incorporated herein by reference in its entirety. FIELD OF INVENTION The technical field generally refers to a portable laser device that can be used for material processing operations, and more specifically to a portable laser device configured with a plasma sensor. BACKGROUND OF THE INVENTION The use of lasers in materials processing applications has increased over the past four decades and is becoming increasingly important in modern manufacturing processes. Lasers are used in a variety of applications, including welding, cutting, drilling, surface hardening, and additive manufacturing. Fiber lasers, in particular, offer several advantages over other laser technologies, such as excimer or CO2 systems. For example, fiber laser technology provides lower maintenance costs by eliminating downtime, reducing spare parts inventory, decreasing gas and electricity processing costs, and, in many cases, reducing the labor costs associated with maintaining older types of lasers.In addition to a lower total cost of ownership, fiber laser technology also offers high wall-plug efficiencies, long diode lives, minimal maintenance, and versatility, as the same unit can often cut, weld, or drill. Due to their small size, fiber lasers are also easily portable. Furthermore, they offer low beam divergence and require no preheating since there is no change in spot size with power, and they possess a large dynamic range. Until now, portable laser devices have been used in low-power applications, including medical devices and diagnostic instrumentation. While higher-power lasers (e.g., at least 1 kW) have been conventionally used for industrial cutting and welding, these systems have typically been too expensive for many smaller machine shops or other smaller-scale end users. However, over time, the average power of laser diodes has increased significantly, while their average price per watt has decreased exponentially. Furthermore, technological advancements have been made in higher-power laser systems. These factors make it more feasible to implement higher-power lasers in smaller material processing systems, such as portable laser devices.These systems would not only be desirable for smaller industrial workshops, but these devices would be especially useful in applications where larger systems are impractical or impossible to use. For example, these portable, easily moved devices are useful in small workspaces and can be used in applications with irregular geometries or shapes. At least one of these objectives is hindering the conventional use of large water-based or liquid-coolant-based chillers used to cool lasers. The large size associated with these systems not only makes them more difficult to maneuver, but can also make them unusable in small workspaces. With the increase in laser power, so too are the hazards associated with laser light. Because laser light used in machining operations such as welding and cutting (e.g., infrared) is invisible to the human eye, the hazards may not be readily apparent to a user. If there is a problem with the laser energy emanating from the handheld device, this may not be easily noticeable. For example, if the laser energy is reflected off the workpiece material instead of being absorbed, the reflected energy can potentially harm the user, as they may inadvertently be exposed to prolonged, invisible radiation because they believe the laser is not working. BRIEF DESCRIPTION OF THE INVENTION The non-limiting aspects and examples relate to methods and systems for material processing operations using a portable laser device. According to one aspect of the disclosure, a portable laser system is provided that includes a laser source configured to generate laser radiation at a wavelength to perform a material processing operation on a workpiece material with a laser beam of the generated laser radiation, a plasma sensor configured to detect plasma emitted from the workpiece material during a material processing operation, and a controller coupled to the plasma sensor and configured to: compare an optical intensity value obtained by the plasma sensor with a threshold value at a time when a predetermined period of time has elapsed after the material processing operation has begun, and produce a control command based on the comparison. In some aspects, the control command turns off the power to the laser source when the optical intensity value is less than the threshold value, and maintains the power to the laser source when the optical intensity value is at or greater than the threshold value. In additional aspects, the default time period is at least 100 microseconds (ps). In some respects, the portable laser system also includes at least one optical filter configured to block light at the wavelength of the emitted laser light from reaching the plasma sensor. In some aspects, the portable laser system also includes an air cooling system coupled to the laser source to dissipate heat. In addition, the portable laser system also includes a laser module that houses the laser source, the air cooling system, and the controller. In additional aspects, the laser module is configured to be mounted on a movable cart. In some respects, the portable laser system also includes a housing configured as a portable device that has an output for the laser beam. In additional aspects, the portable laser system also includes at least one movable mirror placed inside the housing, the at least one movable mirror configured to oscillate the laser beam. In additional aspects, the portable device is of one-piece construction. In additional aspects, the portable device is configured with a modular joining system for a nozzle. In additional aspects, the portable device is configured to be cooled by gas. In additional aspects, the portable device is configured to weigh less than approximately 1 kilogram (kg). In additional aspects, the plasma sensor is placed inside the portable device. In addition, the portable laser system also includes an optical fiber that connects the portable device to the laser source. In some aspects, the portable device also includes an activator coupled to at least one of the controller and a shielding gas source that controls the activation of the shielding gas. In additional aspects, the activator is a first activator and the portable device further comprises a second activator coupled to at least one of the controller and the laser source that controls the activation of the laser source. In additional aspects, the first and second activators are configured in a two-stage arrangement such that the second activator will not activate the laser source unless the first activator is activated. In some aspects, the laser beam has a power of at least 1 kW. bcnzzn / cznz / a / viAi In some aspects, the laser beam has a power of approximately 1.5 kW. In some respects, the laser beam has a power within a range of 500 W to 3 kW inclusive. In some respects, the laser source is configured to: generate laser radiation in a continuous wave (CW) mode that has a certain output power, and generate laser radiation in a high peak power (HPP) mode characterized by having a maximum peak power that is less than twice the output power of the CW mode, a maximum duty cycle of approximately 20%, and a maximum pulse repetition frequency of approximately 1500 Hz. In some respects, the wavelength is infrared (IR) light and at least one optical filter is configured as an IR suppression filter. According to another aspect of the disclosure, a method is provided that includes directing a laser beam from a laser source onto a workpiece material, activating a plasma sensor configured to detect plasma emitted from the workpiece material during a material processing operation, comparing an optical intensity value obtained by the plasma sensor with a threshold value at a time when a predetermined period of time has elapsed after the material processing operation has begun, and producing a control command based on the comparison. In some aspects, the control command turns off the laser source when the optical intensity value is less than the threshold value and maintains power to the laser source when the optical intensity value is at or greater than the threshold value. In additional aspects, the method includes placing at least one optical filter configured to block light at a wavelength from the laser source such that light at the wavelength of the laser source does not reach the plasma sensor. In additional aspects, the method includes providing a housing configured as a portable device that has an output for the laser beam. In additional aspects, the method includes providing an optical fiber that couples the portable device to the laser source. In some aspects, the method involves oscillating the laser beam. According to another aspect of the disclosure, a portable laser system is provided that includes a laser source configured to generate laser radiation at a wavelength to perform a material processing operation on a workpiece material with a laser beam of the generated laser radiation, and a housing configured as a portable apparatus having an outlet for the laser beam, the portable apparatus being configured to be gas-cooled. In additional aspects, the portable laser system includes an optical fiber that connects the portable device to the laser source. In some aspects, the portable device is of one-piece construction. In some aspects, the portable device is configured with a modular joining system for a nozzle. In some aspects, the portable laser system also includes an air cooling system coupled to the laser source to dissipate heat. In some aspects, the portable laser system also includes a laser module that houses the laser source, the air cooling system, and the controller. In additional aspects, the laser module is configured to be mounted on a movable cart. In some aspects, the laser beam has a power of at least 1 kW. Still other aspects, modalities, and advantages of these example aspects and modalities are discussed in detail below. Furthermore, it is understood that both the preceding information and the following detailed description are merely illustrative examples of various aspects and modalities, and are intended to provide an overview or framework for understanding the nature and character of the claimed aspects and modalities. The modalities disclosed herein may be combined with other modalities, and references to a modality, an example, some modalities, some examples, an alternative modality, several modalities, a modality, at least one modality, this and other modalities, certain modalities, or the like are not necessarily mutually exclusive and are intended to indicate that a particular feature, structure, or characteristic described may be included in at least one modality.The appearances of these terms in the present do not necessarily refer to the same modality. BRIEF DESCRIPTION OF THE FIGURES Various aspects of one or more embodiments are discussed below, with reference to the accompanying figures, which are not intended to be drawn to scale. The figures are included to provide illustration and further understanding of the various aspects and embodiments, and are incorporated into and form a part of this specification, but are not intended as a definition of the boundaries of any particular embodiment. The figures, together with the rest of the specification, serve to explain the principles and operations of the aspects and embodiments described and claimed. In the figures, each identical or nearly identical component illustrated in several figures is represented by a similar number. For the sake of clarity, not every component can be labeled in every figure. In the figures: FIGURE 1 is a schematic representation of an example of a portable laser system in accordance with aspects of this disclosure; FIGURE 2 is another schematic representation of an example of a portable laser system in accordance with aspects of this disclosure; Figures 3A to 3F illustrate various views of an example of a portable laser apparatus in accordance with aspects of this disclosure; and FIGURE 4 is a schematic diagram of an oscillating laser beam emanating from the tip of a portable device according to aspects of the invention. DETAILED DESCRIPTION OF THE INVENTION As discussed earlier, technical and economic advances are driving demand for portable lasers with power outputs of at least 1 kW. Portable laser devices with these power levels also present a separate set of safety issues. For example, the user of such a portable device might mistakenly believe that no laser energy is being emitted, since there is no evidence of processing taking place in the workpiece material. This could be caused by any number of different things, such as a damaged laser head, the type of workpiece material being processed, or the method or manner in which the user is operating the laser. As a result, instead of being absorbed by the workpiece material, the laser energy is reflected off the material.The user may mistakenly believe that the laser is not working since the radiation is invisible to them, and as a result, they involuntarily undergo prolonged exposure to radiation. This disclosure discloses a portable laser device that addresses the problem described above. The portable laser device is configured with a plasma sensor capable of rapidly detecting non-laser wavelength plasma created during a proper material processing operation. When something prevents normal processing, such as a laser beam incorrectly focused on the workpiece material, a controller shuts off the laser. This prevents prolonged exposure to laser light by a user. Furthermore, in some embodiments, the device is air-cooled, which significantly reduces the system size compared to water- or liquid-coolant-based laser cooling systems. As discussed below, in at least one embodiment, the laser module associated with the portable component can be fitted onto a standard welding carriage.This reduced footprint is advantageous in many processing environments where available workspace is minimal and / or a more portable unit is desirable. It should be noted that, although air-cooled laser systems are described herein, the scope of this disclosure also extends to water-cooled systems, particularly in cases where higher power levels (e.g., multiple kW) are employed. Figure 1 illustrates a schematic of an example of a portable laser system 100 for performing a material processing operation on a workpiece 105. Non-limiting examples of material processing operations include cutting, welding, brazing, surface modification (e.g., material removal such as cleaning), drilling, and in some cases, coating. The portable laser system 100 (also referred to herein as the “laser system” or simply the “system”) includes a laser source 115, a plasma sensor 135, and a controller 150. The portable laser system 100 further comprises a housing configured as a portable apparatus 120 (also referred to herein as a handheld device), and an optical fiber 130 that couples the laser source 115 to the portable apparatus 120.According to at least one embodiment, the portable laser system 100 further includes a laser module 110 that houses the laser source 115 and, in some cases, the controller 150. The laser module 110 may also include an air-cooling system 140 that cools the laser source 115. In certain embodiments, the portable laser system 100 also includes at least one optical filter 137. The laser source 115 is configured to generate laser radiation at a wavelength to perform a material processing operation on the workpiece 105 with a laser beam 122 of the generated laser radiation. The laser source 115 may include an ytterbium (Yb) laser capable of generating a laser within the near-infrared spectral range (e.g., a center wavelength ranging from approximately 1030–1080 nm). Other lasers are also within the scope of this disclosure, including Yb lasers in the 978–1020 nm range, erbium lasers, and thulium lasers. As will be seen, the laser radiation generated and emitted by the laser source 115 is propagated through an optical fiber 130 extending from the laser source 115 through the handheld apparatus 120, where the laser radiation in the form of a beam 122 is emitted through the outlet 123.The laser source 115 may comprise one or more laser diodes that generate laser radiation propagating through the optical fiber 130. As such, the assembly may be collectively referred to as a fiber laser. In some configurations, the optical fiber 130 is at least 3 meters (m) long, and may be 5 or even 10 m long. Shorter and longer lengths are also within the scope of this disclosure. Depending on the configuration, different applications may require optical fiber 130 of different sizes (e.g., core diameter). For example, systems that emit single-mode (SM) laser radiation will have fiber core diameters that are smaller than those that generate multimode (MM) laser radiation. The system 100 can be configured to accommodate optical fiber 130 of different sizes depending on the desired output mode. According to at least one configuration, the laser beam 122 generated by the laser source 115 has a power of at least 1 kW, and according to another configuration, the laser beam 122 has a power of at least 1.5 kW. In other configurations, the laser beam 122 has a power of approximately 2 kW. In still other configurations, the laser beam 122 has a power of approximately 3 kW. Lower and higher output powers are also within the scope of this disclosure. For example, in some applications, the laser source 115 is configured to generate a laser beam 122 that has a power of less than 1 kW. According to at least one configuration, the laser source 115 is configured to generate a laser beam 122 that has a power within the range of 500 W to 3 kW inclusive. In another configuration, the laser beam 122 has a power within the range of 1 kW to 3 kW inclusive.In another mode, the laser source 115 is configured to generate a laser beam 122 that has a power within a range of 500 W to 1 kW inclusive. The 115 laser source can be configured to emit or otherwise generate single-mode (SM) or multi-mode (MM) light and can be operated in continuous or driven mode. In some configurations, the 115 laser source is configured to generate driven laser light with a high peak power (HPP). This HPP mode may involve operating a continuous-wave (CW) laser in driven mode with up to a twofold increase in peak power compared to the average CW power for short duty cycles (e.g., 0–20%). In some configurations, the HPP mode has a maximum duty cycle of approximately 20% (inclusive). In certain configurations, the duty cycle for HPP mode is within the range of 0–20% inclusive; in other configurations, the duty cycle is within the range of 0%.In some modes, the duty cycle is between 1 and 20% inclusive, and in others, it is between 10 and 20% inclusive. The HPP mode can also be characterized by having a maximum laser pulse frequency (pulse repetition frequency) of 1500 Hz (inclusive), although higher laser pulse frequencies are within the scope of this disclosure. According to one non-limiting modality, the laser source 115 is configured to generate laser radiation in a CW mode with a certain output power, and to generate laser radiation in an HPP mode characterized by having a maximum peak power that is less than twice the output power of the CW mode, a maximum duty cycle of approximately 20%, and a maximum pulse repetition frequency of approximately 1500 Hz. In one example, the peak power in HPP mode is 900 W.In another example, the peak power is 2500 W. In one example, the average CW power is approximately 1500 W. The HPP mode offers several advantages to the portable laser, as this mode of operation allows for welding thicker workpieces and highly reflective metals such as copper. HPP also enhances cutting operations, as it cuts through thick metals faster and creates a smaller opening, reducing the amount of debris reaching the top and, consequently, the amount of spatter. A non-limiting example of a laser configured as an HPP laser includes the YLS-HPP and YLR-HPP systems available from IPG Photonics (Oxford, Massachusetts). Depending on the mode, the laser source 115 and / or the laser beam 122 can be classified as a high-level Class IV laser (IEC Laser Classification). According to some embodiments, the laser source 115 is configured as a Fabry-Perot MM laser as described in U.S. Patent No. 9,647,410, which is owned by the Applicant and incorporated herein by reference. This system may comprise a fiber oscillator comprising an active MM fiber having a monolithic core doped with light emitters, two passive MM fibers spliced ​​to respective opposite ends of the active MM fiber, and fiber MM Bragg gratings (FBGs) written on the respective cores of the passive MM fibers, functioning to define a resonant cavity between them. The generated laser radiation emits at a desired wavelength and has a spectral linewidth within a range of approximately 0.02 nm to approximately 10 nm. According to a further aspect, a pump that laterally pumps the active fiber may also be included. In some configurations, the laser source can be set to generate SM laser radiation. In these cases, the spot size of the laser beam can be smaller (for example, at least 5 times smaller) than that generated for MM laser radiation, offering the advantage of being useful for copper welding. The housing configured as a portable device 120 has an output 123 or laser beam output 122. Throughout this description, the term “portable” refers to a laser device that is both small and light enough to be easily held and operated by one or both of a user’s hands. Furthermore, the portable laser device must be portable so that it can be easily moved by the user during laser processing. However, although the embodiments of the present invention are termed portable and can be used as stand-alone portable devices, the portable laser device can, in some embodiments, be connected to and used in conjunction with stationary equipment. According to certain configurations, the Portable Device 120 weighs less than 2.26796 kg (5 lb) (without fiber), and in some configurations, the Portable Device 120 weighs less than 1.36078 kg (3 lb). According to one configuration, the Portable Device 120 weighs less than 1 kilogram (kg). Furthermore, the Portable Device 120 has length and width dimensions of less than 30.48 cm (12 in), for example, see the side view of the Portable Device 120 in FIGURE 3F. In one example, the Portable Device 120 has a width dimension of less than 25.4 cm (10 in). The entire System 100, according to some configurations, has a maximum weight of 53 kg (118 lb). bcnzzn / cznz / a / viAi According to at least one design, the Portable Device 120 is of one-piece construction (also known as monolithic or integrated construction). The exterior of the Portable Device 120 is formed from a single, integrated material and is not screwed or otherwise fastened from separate sections. This type of construction offers several advantages. For one, the one-piece construction provides a more sealed internal environment compared to devices configured with a multi-part construction that is mechanically fastened together. This feature enhances the protection of the Portable Device 120's internal components, such as lenses and other optical components, optical fiber, gas lines, etc., and allows for higher power outputs per device. According to some models, the Portable Unit 120 is configured with a modular nozzle attachment system. This allows the Portable Unit 120 to function as a single "base module," thus enabling interchangeability and flexibility by providing different nozzles for various applications (e.g., cleaning, welding, drilling, coating). This is implemented at least in part by the Portable Unit 120 being configured to internally integrate various auxiliary and / or other components, such as shielding gas, a protective window, and safety features such as safety interlock conductors, all integrated within the unit. The handheld device 120 is also configured to provide a clear line of sight (for the operator) to the processing area (i.e., where the material processing operation occurs on the workpiece surface) of the workpiece 105. This is evidenced by the views shown in FIGURES 3C and 3D, where the angled portion 113 (see also FIGURE 3F) of the handheld device 120 is configured not to obstruct the line of sight along the dimension of the device that includes the nozzle 112. No other portion or joint obstructs this line of sight either. This allows the user to have a direct line of sight to the nozzle tip and provides the user with better visibility of the processing area during material processing operations. During a suitable material processing operation, the heat from the laser beam 122 of the laser source 115 causes the workpiece material 105 to generate a plasma 107. This plasma 107 radiates radiation at a wavelength or wavelengths different from those of the laser beam 122. For example, the light from the laser source 115 may emit at a wavelength in the infrared range, while the plasma generated from the processing beam may have wavelengths in the ultraviolet and visible regions of the electromagnetic spectrum. The plasma sensor 135 is configured to detect plasma emitted from the workpiece material 105 during a material processing operation. The plasma sensor 135 can be a photodetector, such as a photodiode. The photodetector converts the received plasma light into electrical energy (e.g., a current signal) that corresponds to optical intensity data.These optical intensity data are analyzed by the controller 150, as discussed in further detail below. As will be seen, the current generated by the photodetector can then be converted into optical intensity data by the controller 150. According to at least one non-limiting example, the photodetector can have a bandwidth of up to or greater than approximately 1 MHz. However, it will be seen that the bandwidth of the photodetector will depend on a particular application, as well as other components, including the length of the optical fiber 130. Unlike some conventional laser systems, the configuration described here does not have to include an additional spectrometer, making the system cheaper and less complicated to operate. As shown in the example in Figures 1 and 2, at least one optical filter 137 is configured to block or otherwise absorb light at the wavelength of the emitted laser light (from the laser source 115) so that it does not reach the plasma sensor 135. One or more optical filters 137 can be placed upstream of the plasma sensor 135 and filter out wavelengths of light associated with the laser source 115, such as laser source light reflected from the workpiece material 105. For example, at least one optical filter 137 can be configured to block approximately 99.9% of the light from the laser source 115, such as 1070 nm (IR) light emitted from a Yb laser source 115. Therefore, the optical filter 137 can be configured as an IR suppression filter. Optical filter 137 is designed to allow light wavelengths associated with plasma to reach and be detected by plasma sensor 135.For example, infrared light wavelengths can be blocked by the optical filter 137, but visible and near-UV light passes through (e.g., 300–750 nm). In one configuration, the optical filter is constructed of KG3 glass (manufactured by Schott Optical Company). In some cases, the optical filters 137 are integrated with the plasma sensor 135. A non-limiting example of this device is the OSD Series E photodetector available from OSI Optoelectronics, Inc. of Hawthorne, California. Although the examples discussed herein include an optical filter to block the wavelengths of light associated with the processing laser, it will be appreciated that in certain cases the plasma sensor can be configured to be insensitive to these wavelengths. The controller 150 is coupled to the plasma sensor 135, as shown in FIGURES 1 and 2, so that it is able to receive optical intensity data from the plasma sensor 135. The controller 150 is also in communication with the laser source 115, including its power supply, so that the controller can control the power (i.e., turn the power on and off) to the laser source 115. bcnzzn / cznz / a / viAi As you will see, the 135 plasma sensor can be used in combination with a logarithmic amplifier. Controller 150 is configured to compare an optical intensity value obtained by plasma sensor 135 with a threshold value at a predetermined time after a material processing operation has begun. Once laser source 115 is activated by the user and a material processing operation has started, the clock begins for the predetermined time period. This predetermined time period can be pre-programmed or otherwise determined by the controller. During this predetermined time period, optical intensity data is collected by plasma detector 135 and sent to controller 150. The controller 150 is pre-programmed or otherwise configured to determine a threshold value for the optical intensity data associated with plasma 107. This threshold value represents a normal or otherwise acceptable optical intensity value for the plasma generated during the material processing operation. Therefore, optical intensity can be associated with the brightness or luminance of plasma 107. The predetermined time period can be associated with a typical or otherwise acceptable amount of time for plasma 107 to be generated by the laser beam 122 during normal operation. This will depend on any number of different factors, including the workpiece geometry and material, the laser power, and the laser type and configuration. According to some modalities, the threshold value may also depend on the type of material used as the workpiece and / or the type of application being performed.For example, aluminum and steel may have different threshold values, and a cleaning operation may require a different threshold than welding and / or drilling operations. According to certain modes, the default time period is less than one second, and in some cases, it may range from 10 microseconds (ps) to 100 milliseconds (ms). According to one mode, the default time period is at least 10 ps, ​​and according to another mode, it is at least 100 ps. In still other modes, the default time period is at least one second. The analysis time by the controller 150 can be (at a minimum) as soon as the default time period has elapsed. In some cases, the plasma sensor 135 may collect a series of measured optical intensity values, and the controller 150 then uses an average or maximum to perform the comparison with the threshold value.In other cases, the 150 controller can integrate measured optical intensity data and use this information to perform the comparison. According to some configurations, the default time period can also be a function of the laser power. For example, some applications may require (or the user may desire) that the laser reach full power before performing a material processing operation. In some cases, this may extend the default time period. For example, the default time period may be up to one second. In some cases, the time period for the laser to reach full power may be considered or otherwise accounted for separately from the default time period associated with plasma generation. The 150 controller can be configured to consider both. Controller 150 is also configured to generate a control command based on a comparison between the plasma optical intensity value and the threshold value. For example, Controller 150 will turn off the power to laser source 115 when the optical intensity value is lower than the threshold value. This could mean that a laser beam 122 is indeed being generated, but it is not being absorbed by the workpiece material 105. This presents a potentially hazardous condition for the user. As discussed earlier, other problems can also prevent plasma from being created. Controller 150 will maintain power to laser source 115 when the optical intensity value is at or above the threshold value. This would indicate normal material processing conditions.In other words, a threshold is set for the expected light energy of the material processing operation, and the laser source 115 is switched off by the controller 150 if this expected light energy is not detected within a specified time. The threshold value may depend on the application and other factors, including laser power, beam configuration, and workpiece materials and material geometries. In some cases, the threshold value will be a percentage (%) of an expected value, such as 10–50% of an expected value, for example, an expected value at a particular laser power. It is also worth noting that a noise filter may be included or otherwise implemented by the controller 150 to filter out noise that would impede its ability to process the optical intensity data.The threshold value can also be set to account for or otherwise accommodate applications where the laser is modulated (i.e., the laser power varies, such as in driven mode). For example, the laser power can be modulated when the laser is operating with oscillation capability (described in more detail below). The controller 150 can be any computing device (or devices) that includes at least a processor, memory, input / output components as will be readily apparent to those skilled in the art, and is capable of receiving, transforming, and / or analyzing data from the plasma sensor 135. The controller 150 may include hardware and / or software capable of transforming and / or analyzing information from the plasma sensor 135 and other components of the device or system. The portable laser system 100 also includes an air-cooling system 140 that attaches to the laser source 115 for heat dissipation. As mentioned previously, air cooling of the device greatly reduces the system size compared to laser cooling systems based on water or liquid coolant. According to at least one embodiment, the system 100 may also include a laser module 110 that houses the air-cooling system 140, the laser source 115, and the controller 150. As shown in FIGURE 1, the laser module 110 can be configured to be mounted on a movable cart 160. In one example, the movable cart 160 has the dimensions of a standard welding cart, for example, 91.44 cm (36 in) or less in length and height, and 60.96 cm (24 in.) or less in width, although it should be noted that some welding carriages may have dimensions that differ slightly or otherwise from those listed herein. According to one embodiment, the laser module 110 itself can be sized to be less than 66.04 cm (26 in.) in length, less than 31.75 cm (12.5 in.) in width, and less than or equal to 53.34 cm (21 in.) in height. With reference now to FIGURES 3A-3F, there are several views of a non-limiting example of a portable apparatus 120 that is sized and shaped for user portability for the purpose of performing laser material processing operations such as welding or cutting. In this example embodiment, the portable laser device resembles a pistol shape.According to some configurations, the 100 system may also include a wire feeder module (not shown in the FIGURES) that can be configured as a separate module, or in some cases, integrated with the 110 laser module. The 150 controller can also be configured to control this wire feeder module. According to another aspect, the portable device 120 is configured for gas cooling. For example, the portable device 120 may have one or more inlets for a gas, such as a shielding gas (or air in certain applications), which is directed through one or more conduits inside the portable device 120. This means that no cooling water (or other liquid cooling fluid) passes through the portable device 120. In one embodiment, the shielding gas is directed to two (or more) conduits or channels located at an inlet or otherwise internally within the portable device (generally shown as 124 in FIGURE 3A), and the conduits pass through the interior and exit at a gas outlet located in the vicinity of the laser beam outlet 123. In some cases, the gas is shielding gas that may exit through the nozzle (for example, the nozzle 112 in FIGURES 3A-3C).As the gas passes through the interior of the portable unit 120, it cools various heated components, such as optical components (e.g., lenses, mirrors) and / or electronic components such as motors. Supplying or otherwise directing a gas such as shielding gas through the housing / portable unit 120 not only cools the heated internal components but also adds to the nozzle core concept discussed earlier, since no external piping or wiring is required. According to the example shown in FIGURES 3A-3F and according to at least one modality, the plasma sensor 135 can be placed inside an interior of the portable apparatus 120. This is shown more clearly in FIGURE 3E, which includes a cutaway view of a portion of the interior of the portable apparatus 120. In alternative modality, the plasma sensor 135 can be placed on an exterior of the portable apparatus 120. According to at least one embodiment, the portable apparatus 120 includes an actuator, button, or switch 125 (and may be referred to herein simply as an actuator) that couples to at least one of the controller 150 and a shielding gas source 145 that controls the activation of the shielding gas. For example, as shown in FIGURES 3A and 3B, the shielding gas 145 can be guided through a tube within a flexible conduit 117 that also houses the optical fiber 130 and then through a nozzle 112 and a removable processing tip 126 where it can be dispensed onto the workpiece material. As will be seen, the shielding gas prevents the workpiece material from overheating during processing and / or prevents residues from contaminating the components of the portable apparatus 120. The portable apparatus 120 also includes an actuator, button, or switch 121 (also referred to herein simply as an actuator) that is coupled to at least one of the controller 150 and the laser source 115 and controls the activation of the laser source 115. As shown in FIGURES 3A and 3B, the electrical wiring 119 placed inside the flexible conduit 117 may include wiring such that the actuator 121 is in communication with at least one of the controller 150 or the laser source 115 to control the activation of the laser source 115. According to at least one embodiment, activator 125 is a first activator and activator 121 is a second activator configured in a two-stage arrangement such that the second activator 121 will not activate the laser source 115 unless the first activator 125 is already activated. For example, during operation, a user will first press activator 125 to activate the shielding gas. The user can then press activator 121. The second activator 121 will only activate the laser source 115 if the first activator 125 is pressed. This prevents damage to the workpiece material 105 and / or the portable device 120. One or both of the first actuator 125 and the second actuator 121 can also be configured to have independent functionality. For example, the second actuator 121 can be released without releasing the first actuator 125 to turn off the laser, and then pressed again to turn the laser on if the first actuator 125 is still pressed. Additionally, the first actuator 125 can be released independently of the state of the second actuator 121 to turn off the laser. As can be seen, the actuator buttons can be part of a general safety interlock system that includes several interlock loops. For example, the first actuator 125 can be coupled to an interlock loop that closes when the first actuator 125 is pressed. The second actuator 121 can be a start button and an additional interlock loop that closes when pressed. Furthermore, pressing the first actuator 125 will ignite the shielding gas if one or more interlock loops are active, for example, a key switch interlock loop coupled to the controller (processor) and laser, an emergency stop loop, a fiber interlock loop, and an external interlock loop. When the first actuator is released, the shielding gas can be kept igniten for a predetermined duration (for example, set by a user).The second trigger 121 can act as a start button for the laser. If the switch is open for more than a predetermined amount of time (e.g., 300 ms) and then trigger 121 is pressed, the laser will fire provided that the safety conditions have been met and the shielding gas has been on for a predetermined period of time (and in some cases, as mentioned above, the laser has reached a desired output power level). As mentioned previously, the portable laser may include several safety interlock loops that prevent laser operation if a fault is detected. Non-limiting examples of such interlock loops include a key switch / electronic stop interlock loop, an external interlock loop (e.g., an interlock loop that couples with the laser system and a user's external safety mechanism), a fiber interlock loop, a head nozzle and safety clamp interlock loop, a two-level trigger interlock loop, a safety interlock loop, and a current source interlock loop.Other non-limiting examples of safety interlock loops that may be included in the device include those associated with temperature (e.g., device temperature and / or air sensors), gas pressure, and / or additional photodetectors (e.g., for back reflection, dirty window, fiber fuse, etc.). To assist the user, the handheld device 120 can also be configured with one or more status lights 127 (for example, see FIGURE 3D) that inform the user of the device's operating status. When the status lights 127 are not illuminated, this indicates a default state (i.e., no shielding gas or laser light energy is being emitted from the handheld device). When the user presses trigger 125, this activates the shielding gas, which in turn activates status light 127a (or alternatively, 127b). This signifies to the user that shielding gas is being emitted. Once the user presses trigger 121 (while still pressing trigger 125), this activates the laser source 115, which in turn activates status light 127b (or alternatively, 127a).When both status lights 127a and 127b are illuminated, this means to the user that shielding gas and laser light are being emitted from the handheld device 120. In some cases, this may signify to the controller 150 the start of the predetermined time period discussed earlier. The portable device 120 can also be configured with one or more optical components, such as a replaceable window (indicated as 128 in FIGURE 3C, but located internally) used to protect the internal components of the portable device 120, as well as a replaceable focusing lens (indicated as 129 in FIGURE 3C, but located internally), which is used to focus the laser beam 122 onto the workpiece surface. Other lenses (e.g., a collimating lens) or optical components (e.g., beam splitters, mirrors) can also be implemented within the portable device 120. In some cases, the portable device 120 may include a coupler or other waveguide component for connection to the optical fiber 130.The portable apparatus 120 may also include other components, such as a removable or sliding sleeve or collar 141 (for example, see FIGURES 3B and 3C) that covers connections to components that are inside a flexible conduit 117 that extends between the portable apparatus 120 and the laser module 110, such as optical fiber 130, shielding gas 145, and / or electrical wiring 119. The 100 handheld laser system can also include or otherwise implement one or more additional safety features. For example, in one configuration, the 120 handheld unit is equipped with a position sensor to ensure that the nozzle or tip makes contact with a workpiece surface. For instance, a safety interlock implemented by the 150 controller can be incorporated with the 126 removable processing tip and a power supply for the 115 laser source. During operation, the 150 controller will only activate power to the 115 laser source if the safety interlock is engaged—that is, if the nozzle or tip of the 120 handheld unit makes contact with the workpiece. For example, this can be implemented by electrically connecting the workpiece and the nozzle to the laser system when cutting the workpiece, for instance, via a terminal on a system panel. According to at least one embodiment, the portable device 120 is also configured with beam oscillation capability. For example, at least one movable mirror can be placed within the housing 120, which is configured to oscillate the laser beam 122. The oscillation motion oscillates the laser beam 122 back and forth at a desired frequency (for example, up to and including 300 Hz, minimum of 50 Hz, but it should be noted that other values ​​are within the scope of this disclosure). The movable mirror reflects and moves the laser beam—that is, oscillates—the laser beam on an axis. In some embodiments, the at least one movable mirror is configured to oscillate the laser beam 122 within a field of view defined by a scanning angle within a range of 0.1° to and including 3°. According to other modalities, the scanning angle is within a range of 0.Γ to 7° inclusive, and in other modalities, the scanning angle is within a range of 0.1° to 12° inclusive. Larger scan angle ranges are also within the scope of this disclosure. Different scan angle ranges may be associated with different types of applications. For example, in welding applications, the desired scan angle may be smaller than for cleaning operations. The oscillation capability is possible because the movable mirror pivots around an axis and is driven by a galvanometer motor, which is capable of rapidly reversing direction. For example, controller 150 controls the movable mirror such that the mirror pivots the beam 122 within a scan angle alpha (a), as shown in FIGURE 4, thereby allowing the beam to oscillate. Depending on the focal length (non-limiting examples of which may be 80 mm, 100 mm, 120 mm), a scan angle of 3° represents up to approximately 50 mrad of oscillation.In some cases, the oscillation length (oscillation amplitude) has a minimum value of approximately 0.5 mm and a maximum value of approximately 5 mm, and in some cases, a maximum value of approximately 4 mm. As mentioned above, larger scanning angles are also within the scope of this disclosure, including 80 mrad of oscillation, or 4.5°, and even larger oscillation amplitudes are also feasible, especially for cleaning operations where the amplitude may be greater than 5 mm, such as 0–15 mm. According to at least one aspect, a focusing lens is positioned upstream of the mirror. The oscillation motion can be one-dimensional or two-dimensional if the device is equipped with two movable mirrors. Aspects of the oscillation capability are described in U.S. Patent Application No.15 / 187,235, which is the property of the Applicant and is fully incorporated herein by reference. According to some embodiments, the portable device 120 may also include a fixed mirror. In addition to material processing operations such as welding, as mentioned above, the systems and methods described herein can also be applied to surface modification applications, such as material removal (laser ablation). In these cases, the device can be equipped with a wider nozzle than that used for welding, and the oscillation scan angle can also be increased. Furthermore, the laser source can be operated in driven mode or other modes, including HPP mode. The aspects disclosed herein in accordance with the present invention are not limited in their application to the construction details and component arrangement described below or illustrated in the accompanying figures. These aspects are capable of assuming other forms and of being implemented or carried out in various ways. Examples of specific implementations are provided herein for illustrative purposes only and are not intended to be limiting. In particular, the acts, components, elements, and characteristics discussed in relation to any one or more of these forms are not intended to be excluded from a similar function in any other form. Furthermore, the phraseology and terminology used herein is for descriptive purposes and should not be considered limiting. Any reference to examples, modalities, components, elements, or acts of the systems and methods referred to herein in the singular may also encompass modalities that include a plurality, and any reference in the plural to any modality, component, element, or act herein may also encompass modalities that include only a singularity. It is not intended that references in the singular or plural form limit the systems or methods disclosed herein, their components, acts, or elements. The use herein of "includes," "comprises," "has," "contains," "implies," and variations thereof, is intended to encompass the items listed below and their equivalents, as well as additional items.References using "ao" may be interpreted as inclusive, such that any term described using "ao" may indicate any one, more than one, or all of the terms described. Furthermore, in the case of inconsistent uses of terms between this document and documents incorporated herein by reference, the term "use" in the incorporated reference is complementary to that in this document; for irreconcilable inconsistencies, the term "use" in this document controls. Having described several aspects of at least one example in this way, it should be appreciated that various alterations, modifications, and improvements will readily be presented to those skilled in the technique. For example, the examples disclosed herein can also be used in other contexts. It is proposed that these alterations, modifications, and improvements be included in this disclosure and that they fall within the scope of the examples analyzed herein. Consequently, the preceding description and figures are provided for illustrative purposes only.

Claims

1. A portable laser system, characterized in that it comprises: a laser source configured to generate laser radiation at a wavelength to perform a material processing operation on a workpiece material with a laser beam of the generated laser radiation; a plasma sensor configured to detect plasma emitted from the workpiece material during a material processing operation; and a controller coupled to the plasma sensor and configured to: compare an optical intensity value obtained by the plasma sensor with a threshold value at a time when a predetermined period of time has elapsed after the material processing operation has begun; and produce a control command based on the comparison.

2. The portable laser system according to claim 1, characterized in that the control command turns off the power to the laser source when the optical intensity value is lower than the threshold value, and maintains the power to the laser source when the optical intensity value is at or greater than the threshold value.

3. The portable laser system according to claim 2, characterized in that the predetermined time period is at least 100 microseconds (ps).

4. The portable laser system according to claim 1, characterized in that it further comprises at least one optical filter configured to block light at the wavelength of the emitted laser light from reaching the plasma sensor.

5. The portable laser system according to claim 1, characterized in that it further comprises an air cooling system coupled to the laser source for heat dissipation.

6. The portable laser system according to claim 5, characterized in that it further comprises a laser module housing the laser source, the air cooling system, and the controller.

7. The portable laser system according to claim 6, characterized in that the laser module is configured to be mounted on a movable cart.

8. The portable laser system according to claim 1, characterized in that it further comprises a housing configured as a portable device having an output for the laser beam.

9. The portable laser system according to claim 8, characterized in that the portable apparatus is of one-piece construction.

10. The portable laser system according to claim 8, characterized in that the portable apparatus is configured with a modular joining system for a nozzle.

11. The portable laser system according to claim 8, characterized in that the portable apparatus is configured to be gas-cooled.

12. The portable laser system according to claim 8, characterized in that the portable apparatus is configured to weigh less than approximately 1 kilogram (kg).

13. The portable laser system according to claim 8, characterized in that the plasma sensor is placed inside an interior of the portable apparatus.

14. The portable laser system according to claim 8, characterized in that it further comprises an optical fiber that couples the portable apparatus to the laser source.

15. The portable laser system according to claim 8, characterized in that the portable apparatus comprises an activator coupled to at least one of the controller and a shielding gas source that controls the activation of the shielding gas.

16. The portable laser system according to claim 15, characterized in that the activator is a first activator and the portable apparatus further comprises a second activator coupled to at least one of the controller and the laser source that controls the activation of the laser source.

17. The portable laser system according to claim 16, characterized in that the first and second activators are configured in a two-stage arrangement such that the second activator will not activate the laser source unless the first activator is activated.

18. The portable laser system according to claim 8, characterized in that it further comprises at least one movable mirror placed within the housing, the at least one movable mirror being configured to oscillate the laser beam.

19. The portable laser system according to claim 1, characterized in that the laser beam has a power of at least 1 kW.

20. The portable laser system according to claim 19, characterized in that the laser beam has a power of approximately 1.5 kW.

21. The portable laser system according to claim 1, characterized in that the laser beam has a power within a range of 500 W to 3 kW inclusive.

22. The portable laser system according to claim 1, characterized in that the laser source is configured to: generate laser radiation in a continuous wave (CW) mode having an output power; and generate laser radiation in a high peak power (HPP) mode characterized by having a maximum peak power that is less than twice the output power of the CW mode, a maximum duty cycle of approximately 20%, and a maximum pulse repetition frequency of approximately 1500 Hz.

23. The portable laser system according to claim 1, characterized in that the wavelength is infrared (IR) light and the at least one optical filter is configured as an IR suppression filter.

24. A method, characterized in that it comprises: directing a laser beam from a laser source onto a workpiece material; activating a plasma sensor configured to detect plasma emitted from the workpiece material during a material processing operation; comparing an optical intensity value obtained by the plasma sensor with a threshold value at a time when a predetermined period of time has elapsed after the material processing operation has begun; and producing a control command based on the comparison.

25. The method according to claim 24, characterized in that the control command turns off the laser source when the optical intensity value is less than the threshold value and maintains power to the laser source when the optical intensity value is at or greater than the threshold value.

26. The method according to claim 24, characterized in that it further comprises placing at least one optical filter configured to block light at a wavelength from the laser source such that light at the wavelength from the laser source does not reach the plasma sensor.

27. The method according to claim 24, characterized in that it further comprises providing a housing configured as a portable apparatus having an output for the laser beam.

28. The method according to claim 24, characterized in that it further comprises providing an optical fiber that couples the portable apparatus to the laser source.

29. The method according to claim 24, characterized in that it further comprises oscillating the laser beam.

30. A portable laser system, characterized in that it comprises: a laser source configured to generate laser radiation at a wavelength for performing a material processing operation on a workpiece material with a laser beam of the generated laser radiation; and a housing configured as a portable apparatus having an outlet for the laser beam, the portable apparatus being configured to be gas-cooled.

31. The portable laser system according to claim 30, characterized in that it further comprises an optical fiber that couples the portable apparatus to the laser source.

32. The portable laser system according to claim 30, characterized 23 in that the portable apparatus is of one-piece construction.

33. The portable laser system according to claim 30, characterized in that the portable apparatus is configured with a modular joining system for a nozzle.

34. The portable laser system according to claim 30, characterized in that it further comprises an air cooling system coupled to the laser source for heat dissipation.

35. The portable laser system according to claim 34, characterized in that it further comprises a laser module housing the laser source, the air cooling system, and the controller.

36. The portable laser system according to claim 35, characterized in that the laser module is configured to be mounted on a movable cart.

37. The portable laser system according to claim 30, characterized in that the laser beam has a power of at least 1 kW.

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