Patent Publication Number: US-2022234142-A1

Title: Laser ablation seal slot machining

Description:
FIELD 
     The present subject matter relates generally to laser ablating features into components, such as components for gas turbine engines. 
     BACKGROUND 
     Some aviation gas turbine engine components include one or more cavities or openings. For example, a turbine nozzle assembly can include a plurality of turbine nozzles. Each turbine nozzle typically includes seal slots. The seal slots hold spline seals between adjacent turbine nozzles. Conventionally, turbine nozzles have been formed of metallic materials. The seal slots of such metallic turbine nozzles have frequently been machined with Electric Discharge Machining (EDM) due to the high aspect ratio and tight tolerance requirements of the seal slots. Turbine nozzles are more commonly being formed of Ceramic Matrix Composite (CMC) materials. Using EDM to machine CMC components has certain challenges due to the nonhomogeneous material of such CMC components. Ultrasonic machining has proven successful in machining seal slots in CMC parts. However, similar to EDM, ultrasonic machining typically requires expensive tooling and has a relatively long cycle time. 
     Accordingly, systems and methods that address one or more of the challenges noted above would be useful. 
     BRIEF DESCRIPTION 
     Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention. 
     In one aspect, a method of laser ablating a component to form a cavity is provided. The method includes (a) laser ablating the component to remove a slice of material therefrom so that at least a portion of a section of the cavity is formed. The method further includes (b) laser ablating the component along an outline of the section to remove excess sidewall material therefrom to form one or more sidewalls of the section. In addition, the method includes (c) iterating (a) and (b) of the method to form one or more subsequent sections of the cavity. Further, the method includes (d) after iterating at (c), laser ablating the component to remove excess end wall material therefrom to form an end wall of the cavity to a predetermined depth. 
     In another aspect, a method of laser ablating a turbine nozzle to form a seal slot is provided. The method includes (a) laser ablating the turbine nozzle to remove a slice of material therefrom so that at least a portion of a section of the seal slot is formed. Further, the method includes (b) laser ablating the turbine nozzle to remove excess sidewall material therefrom to form one or more sidewalls of the section of the seal slot. In addition, the method includes (c) laser ablating the turbine nozzle to remove excess end wall material to form an end wall of the seal slot to a predetermined depth. 
     In another exemplary aspect, a non-transitory computer readable medium is provided. The non-transitory computer readable medium includes computer-executable instructions, which, when executed by one or more processors of a controller of a laser system, cause the controller to: (a) cause the laser system to laser ablate a component to remove a slice of material therefrom so that at least a portion of a section of a cavity is formed; (b) cause the laser system to laser ablate the component along an outline of the section to remove excess sidewall material therefrom to form one or more sidewalls of the section; (c) cause the laser system to iterate (a) and (b) for one or more subsequent sections of the cavity; and (d) after iterating at (c), cause the laser system to laser ablate the component to remove excess end wall material therefrom to form an end wall of the cavity to a predetermined depth. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: 
         FIG. 1  is a schematic cross-sectional view of an exemplary gas turbine engine according to various embodiments of the present subject matter; 
         FIG. 2  provides a schematic view of an example laser system for laser ablating components, such as the component depicted in  FIG. 2 , according to an example embodiment of the present subject matter; 
         FIG. 3  provides a flow diagram of a method of laser ablating a component to form a cavity therein according to one example embodiment of the present subject matter; 
         FIG. 4  provides a schematic cross-sectional view of the component of  FIG. 2  with a first slice of material removed therefrom by laser ablation to form a first section of the cavity; 
         FIG. 5  provides a close-up view of Section  5  of  FIG. 4  and depicts one of the tapered sidewalls of the newly formed first section of the cavity; 
         FIG. 6  provides a schematic top plan view of the component of  FIG. 2  after the first slice of material has been removed by laser ablation; 
         FIG. 7  provides a schematic cross-sectional view of the component of  FIG. 2  after the first slice of material has been removed and excess sidewall material forming the first section of the cavity has been removed by laser ablating along an outline of the first section; 
         FIG. 8  provides a schematic cross-sectional view of the component of  FIG. 2  and depicts the laser system removing a second slice of material therefrom by laser ablation; 
         FIG. 9  provides a schematic cross-sectional view of the component of  FIG. 2  with the second slice of material removed therefrom by laser ablation to form a second section of the cavity; 
         FIG. 10  provides a schematic top plan view of the component of  FIG. 2  after the second slice of material has been removed by laser ablation; 
         FIG. 11  provides a schematic cross-sectional view of the component of  FIG. 2  after the second slice of material has been removed and excess sidewall material forming the second section of the cavity has been removed by laser ablating along an outline of the second section; 
         FIG. 12  provides a schematic cross-sectional view of the component of  FIG. 2  with at least a portion of the cavity formed to a predetermined depth; 
         FIG. 13  provides a schematic cross-sectional view of the component of  FIG. 2  with the cavity formed to specification; and 
         FIG. 14  provides an example computing system in accordance with an example embodiment of the present subject matter. 
     
    
    
     Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention. As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows and “downstream” refers to the direction to which the fluid flows. 
     Aspects of the present disclosure are directed to systems and methods of laser ablating features into components, such as components for gas turbine engines. In one example aspect, a method of laser ablating a component to form a cavity is provided. The component can be a turbine nozzle of a gas turbine engine and the cavity can be a seal slot thereof, for example. The component can be formed of a Ceramic Matrix Composite (CMC) material or another suitable material. The method includes laser ablating the component to remove a slice of material therefrom so that at least a portion of a section of the cavity is formed. A laser system can be used to laser ablate the component. A controller of the laser system can control various components so that a laser beam scans or shoots along the component in a predefined pattern to remove the slice of material. As the laser beam travels into the cavity proximate the sidewalls of the section being formed, the laser beam can clip the top surface of the component due to the conical shape of the laser beam. This results in less energy at the machining surface, and consequently, the sidewalls of the newly formed section can be tapered. 
     With the slice of material removed, the method includes laser ablating the component along an outline of the section to remove excess sidewall material therefrom to form one or more sidewalls of the section. For instance, the laser beam can be controlled to trace around the outline of the section to remove the excess sidewall material. That is, the laser beam can be specifically shot along the outline to remove tapering of the sidewalls. The controller of the laser system can control various components so that the laser beam scans or shoots along the outline of the section in a predefined pattern to remove the excess sidewall material. With the excess sidewall material removed, the section of the cavity can be fully formed to specification. The process of laser ablating the component to first remove a slice of material and then second to make a pass along the outline can be iterated for one or more subsequent sections of the cavity. Stated another way, the process can be iterated to form the depth of the cavity. 
     In some instances, multiple outline laser shots can be performed to remove the excess sidewall material, particularly for sections at greater depths of the cavity. For instance, for a section at the opening end of the cavity, only one outline shot may need be performed. However, for a subsequent section formed at a greater depth of the cavity than the section at the opening end of the cavity, multiple outline laser shots may need be performed to remove the excess sidewall material. 
     After iterating the two-step process noted above, the method includes laser ablating the component to remove excess end wall material therefrom to form an end wall of the cavity to a predetermined depth. The excess end wall material can have a rounded shape along a cross section thereof. The rounded shape of the excess end wall material can have an outline or perimeter at a greater depth than a remainder portion of the rounded shape. The controller of the laser system can control various components so that the laser beam scans in a predefined pattern to remove the excess end wall material. In this way, the end wall can be formed to specification, e.g., the end wall can be made flat or perpendicular to the depth of the cavity. 
     Advantageously, the systems and methods provided herein can eliminate or reduce the challenges associated with laser ablating cavities in components, particularly cavities with high aspect ratios, such as seal slots of turbine nozzles. For instance, the tapering of sidewalls due to clipping of the laser beam on the top or outer surface of the component can be eliminated or greatly reduced using the systems and methods provided herein. Further, hard tooling is typically not required for laser ablation, unlike conventional machining processes, and the machining cycle time for a given component can also be reduced. Moreover, laser ablation can be used to machine components with a wide variety of materials, including components formed of CMC or metallic materials. The present systems and methods have other advantages and benefits as well. 
       FIG. 1  provides a schematic cross-sectional view of a gas turbine engine in accordance with one example embodiment of the present subject matter. For the depicted embodiment of  FIG. 1 , the gas turbine engine is a high-bypass turbofan jet engine  10 , referred to herein as “turbofan  10 .” The turbofan  10  defines an axial direction A (extending parallel to a longitudinal centerline  12  provided for reference), a radial direction R, and a circumferential direction extending in a plane orthogonal to the axial direction A three hundred sixty degrees (360°) around the longitudinal centerline  12 . 
     The turbofan  10  includes a fan section  14  and a core turbine engine  16  disposed downstream from the fan section  14 . The core turbine engine  16  includes a substantially tubular outer casing  18  that defines an annular core inlet  20 . The outer casing  18  encases, in serial flow relationship, a compressor section including a booster or low pressure (LP) compressor  22  and a high pressure (HP) compressor  24 ; a combustion section  26 ; a turbine section including a high pressure (HP) turbine  28  and a low pressure (LP) turbine  30 ; and a jet exhaust nozzle section  32 . A high pressure (HP) shaft or spool  34  drivingly connects the HP turbine  28  to the HP compressor  24 . A low pressure (LP) shaft or spool  36  drivingly connects the LP turbine  30  to the LP compressor  22 . 
     The fan section  14  includes a variable pitch fan  38  having a plurality of fan blades  40  coupled to a disk  42  in a spaced apart manner. As depicted, the fan blades  40  extend outward from the disk  42  generally along the radial direction R. Each fan blade  40  is rotatable relative to the disk  42  about a pitch axis P by virtue of the fan blades  40  being operatively coupled to a suitable actuation member  44  configured to collectively vary the pitch of the fan blades  40  in unison. The fan blades  40 , disk  42 , and actuation member  44  are together rotatable about the longitudinal axis  12  by LP shaft  36 . 
     Referring still to  FIG. 1 , the disk  42  is covered by a rotatable front nacelle  48  aerodynamically contoured to promote an airflow through the plurality of fan blades  40 . Additionally, the fan section  14  includes an annular fan casing or outer nacelle  50  that circumferentially surrounds the fan  38  and/or at least a portion of the core turbine engine  16 . The nacelle  50  may be supported relative to the core turbine engine  16  by a plurality of circumferentially-spaced outlet guide vanes  52 . Moreover, a downstream section  54  of the nacelle  50  may extend over an outer portion of the core turbine engine  16  so as to define a bypass airflow passage  56  therebetween. 
     During operation of the turbofan  10 , a volume of air  58  enters the turbofan  10  through an associated inlet  60  of the nacelle  50  and/or fan section  14 . As the volume of air  58  passes across the fan blades  40 , a first portion of the air  58  as indicated by arrows  62  is directed or routed into the bypass airflow passage  56  and a second portion of the air  58  as indicated by arrow  64  is directed or routed into the annular core inlet  20  and into the LP compressor  22 . The pressure of the second portion of air  64  is then increased as it is routed through the high pressure (HP) compressor  24  and into the combustion section  26 , where it is mixed with fuel and burned to provide combustion gases  66 . 
     The combustion gases  66  are routed through the HP turbine  28  where a portion of thermal and/or kinetic energy from the combustion gases  66  is extracted via sequential stages of HP turbine stator vanes  68  that are coupled to the outer casing  18  and HP turbine rotor blades  70  that are coupled to the HP shaft or spool  34 , thus causing the HP shaft or spool  34  to rotate, thereby supporting operation of the HP compressor  24 . The combustion gases  66  are then routed through the LP turbine  30  where a second portion of thermal and kinetic energy is extracted from the combustion gases  66  via sequential stages of LP turbine stator vanes  72  that are coupled to the outer casing  18  and LP turbine rotor blades  74  that are coupled to the LP shaft or spool  36 , thus causing the LP shaft or spool  36  to rotate, thereby supporting operation of the LP compressor  22  and/or rotation of the fan  38 . 
     The combustion gases  66  are subsequently routed through the jet exhaust nozzle section  32  of the core turbine engine  16  to provide propulsive thrust. Simultaneously, the pressure of the first portion of air  62  is substantially increased as the first portion of air  62  is routed through the bypass airflow passage  56  before it is exhausted from a fan nozzle exhaust section  76  of the turbofan  10 , also providing propulsive thrust. The HP turbine  28 , the LP turbine  30 , and the jet exhaust nozzle section  32  at least partially define a hot gas path  78  for routing the combustion gases  66  through the core turbine engine  16 . 
     It will be appreciated that, although described with respect to turbofan  10  having core turbine engine  16 , the present subject matter may be applicable to other types of turbomachinery. For example, the present subject matter may be suitable for use with or in turboprops, turboshafts, turbojets, industrial and marine gas turbine engines, and/or auxiliary power units. Various features of components of the turbofan  10  can be machined by laser ablation using the systems and methods described herein. However, it will be appreciated that features of components of other gas turbine engines, engines generally, other turbomachinery, and other machines and/or devices generally can be machined by laser ablation using the systems and methods described herein. 
       FIG. 2  provides a schematic view of an example laser system  100  according to an example embodiment of the present subject matter. For this embodiment, the laser system  100  is operatively configured to form a cavity  210  in a component  200 , such as a component for a gas turbine engine. As one example, the component  200  can be a high pressure turbine nozzle and the cavity  210  can be a seal slot thereof. The seal slot can hold one end of a spline seal and a seal slot of an adjacent nozzle can hold the other end of the spline seal. The component  200  can be other suitable components as well, such as a combustor liner, compressor nozzles, etc. In addition to a seal slot, the cavity  210  can be a recess, an indentation, a channel, a slot generally, a chamber, a blind hole, or the like. The cavity  210  can have any suitable shape or geometry. In  FIG. 2 , the cavity  210  is shown in phantom lines as it has not yet been machined. 
     The component  200  can be formed of any suitable material. As one example, the component  200  can be formed of a Ceramic Matrix Composite (CMC) material. Exemplary matrix materials for a CMC component can include silicon carbide, silicon, silica, alumina, or combinations thereof. Ceramic fibers can be embedded within the matrix, such as oxidation stable reinforcing fibers including monofilaments like sapphire and silicon carbide (e.g., Textron&#39;s SCS-6), as well as rovings and yarn including silicon carbide (e.g., Nippon Carbon&#39;s NICALON®, Ube Industries&#39; TYRANNO®, and Dow Corning&#39;s SYLRAMIC®), alumina silicates (e.g., Nextel&#39;s 440 and 480), and chopped whiskers and fibers (e.g., Nextel&#39;s 440 and SAFFIL®), and optionally ceramic particles (e.g., oxides of Si, Al, Zr, Y, and combinations thereof) and inorganic fillers (e.g., pyrophyllite, wollastonite, mica, talc, kyanite, and montmorillonite). CMC materials may have coefficients of thermal expansion in the range of about 1.3×10 −6  in/in/° F. to about 3.5×10 −6  in/in/° F. in a temperature range of approximately 1000-1200° F. As another example, the component  200  can be formed of other suitable composite materials, such as a Polymer Matrix Composite (PMC) material. As a further example, the component  200  can be formed of a metallic material. 
     As shown in  FIG. 2 , the laser system  100  defines a vertical direction V, a lateral direction L, and a transverse direction T. Each of the vertical direction V, lateral direction L, and transverse direction T are mutually perpendicular to one another and form an orthogonal direction system. For this embodiment, the laser system  100  includes a laser source  102  and a mirror or adjustable lens  104  for directing or focusing a laser beam  106  emitted from the laser source  102 . As depicted in  FIG. 2 , the laser beam  106  is conically shaped. The adjustable lens  104  is adjustable such that the focal or focus point  108  of the laser beam  106  (i.e., the apex or vertex of the cone shaped laser beam  106 ) can be moved or scanned about such that desirable geometries, such as the cavity  210 , in the component  200  can be laser ablated. 
     The laser system  100  also includes an actuator  110 . The actuator  110  is operatively configured to translate, rotate, pivot, actuate, adjust, or otherwise move the adjustable lens  104  between various positions. For example, the actuator  110  can orient the adjustable lens  104  such that the laser beam  106  can be moved about (as shown by the phantom lines in  FIG. 2 ). In this way, the angle of attack of the laser beam  106  can be modified or adjusted such that the cavity  210  can be formed as described herein. The actuator  110  can be any suitable type of actuator  110  capable of orienting the adjustable lens  104 . 
     As further shown in  FIG. 2 , the laser system  100  further includes a controller  112 . The controller  112  is communicatively coupled with the laser source  102  and the actuator  110 . The controller  112  can be communicatively coupled with the laser source  102  and the actuator  110  via one or more signal lines or shared communication busses, or additionally or alternatively, the controller  112  can be communicatively coupled with the laser source  102  and the actuator  110  via one or more wireless connections. 
     Operation of the laser system  100  is controlled by the controller  112 . In some example embodiments, the controller  112  can be communicatively coupled with a control panel that can represent a general purpose I/O (“GPIO”) device or functional block. In some example embodiments, the control panel can include input components or devices, such as one or more of a variety of electrical, mechanical or electro-mechanical input devices including rotary dials, push buttons, touch pads, and touch screens. The control panel provides selections for user manipulation of the operation of the laser system  100 . In response to user manipulation of the control panel, the controller  112  controls operation of the various components of the laser system  100 . The controller  112  can be configured and function in the same or similar manner as one of the computing devices  402  of the computing system  400  of  FIG. 14 . 
     The laser system  100  can be used to laser ablate the component  200  to form a cavity  210 , such as a seal slot. Particularly, the laser system  100  can be used to form the cavity  210  by laser ablating the component  200  to remove a slice of material to form at least a portion of a section of the cavity  210  and then laser ablating an outline of the newly formed section. That is, the laser can be scanned around the outline of the newly formed section of the cavity  210  to remove sidewall taper. The process of laser ablating the component  200  to remove a slice of material to form at least a portion of a section of the cavity  210  and then laser ablating an outline of the newly formed section of the cavity  210  can be iterated section-by-section of the cavity  210 , e.g., until at least a portion of the cavity  210  reaches a predetermined depth. When a portion of the cavity  210  reaches the predetermined depth, the component  200  can be laser ablated to remove excess end wall material so that an end wall of the cavity  210  is formed to the predetermined depth. An example manner in which this process can be implemented is set forth below. 
       FIG. 3  provides a flow diagram of a method ( 300 ) of laser ablating a component to form a cavity therein according to one example embodiment of the present subject matter. General reference will be made to  FIGS. 2 through 13  to facilitate explanation of the method ( 300 ). 
     At ( 302 ), the method ( 300 ) includes laser ablating the component to remove a slice of material therefrom so that at least a portion of a section of the cavity is formed. For instance, as shown in  FIG. 2 , the cavity  210  to be formed can be incrementally laser ablated slice-by slice. For this embodiment, the cavity  210  to be formed is to be incrementally laser ablated in six slices, including a first slice SL 1 , a second slice SL 2 , a third slice SL 3 , a fourth slice SL 4 , a fifth slice SL 5 , and a sixth slice SL 6 . The cavity  210 , when formed, extends between an opening end  212  and a blind end  214 , e.g., along the vertical direction V. Accordingly, when the first slice SL 1  of material is removed by laser ablation, the opening end  212  of the cavity  210  is formed at least in part. When the sixth slice SL 6  of material is removed by laser ablation, the blind end  214  of the cavity  210  is formed at least in part. 
     To remove the first slice SL 1  of material from the component  200 , the laser system  100  causes the laser beam  106  to scan or shoot in a predefined pattern along a surface of the component  200 , e.g. as shown in  FIG. 2 . Particularly, the controller  112  can cause the laser source  102  to emit laser energy at a predefined intensity or power. The controller  112  can cause the actuator  110  to adjust the orientation of the adjustable lens  104  so that the emitted laser beam  106  moves along the surface of the component  200  in the predefined pattern. For instance, the laser beam  106  can be directed about along the lateral direction L between  106 - 1  and  106 - 2 . The laser beam  106  can also be moved along the transverse direction T to form the 3D geometry of the cavity  210 . In this way, the laser beam  106  can scan about to form the desired geometry of the opening end  212  of the cavity  210 . As will be appreciated, when the laser beam  106  strikes the surface of the component  200 , material is removed from the component  200  at that particular localized location. 
       FIG. 4  provides a schematic view of the component  200  with the first slice SL 1  ( FIG. 2 ) of material removed therefrom. As shown, with a majority of the first slice SL 1  ( FIG. 2 ) of material removed by laser ablation, a part of the first section S 1  of the cavity  210  is formed. The depth of the first section S 1  can be controlled by the intensity of the laser beam  106  emitted, among other factors. Due to the conical shape of the laser beam  106 , a portion of the laser beam  106  may clip the outer surface  216  of the component  200  when the laser beam  106  is moved proximate the sidewalls or edges of the section being formed, which results in less energy at the machining surface. Consequently, as shown in  FIG. 4 , the sidewalls of the newly formed portion of the section, which in this instance is the first section S 1 , are tapered. As shown best in  FIG. 5 , a close-up view of one of the tapered sidewalls  220 -S 1  of the newly formed portion of the first section S 1  is depicted. As shown, the tapered sidewall  220 -S 1  is oriented at an angle with respect to the vertical direction V. 
     At ( 304 ), returning to  FIG. 3 , the method ( 300 ) includes laser ablating the component along an outline of the section to remove excess sidewall material therefrom to form one or more sidewalls of the section. By way of example,  FIG. 6  provides a top plan view of the component  200  after the first slice SL 1  of material has been removed by laser ablating, e.g., at ( 302 ) of method ( 300 ). As shown, as a result of removing the first slice SL 1  of material, the newly formed portion of the first section S 1  has tapered sidewalls  220 -S 1 , which is undesirable in this example. Accordingly, to remove excess sidewall material  222 -S 1  (also depicted in  FIG. 5  within the dashed-line triangle), the component  200  is laser ablated once again. Particularly, an outline OT-S 1  of the first section S 1  is laser ablated to remove the excess sidewall material  222 -S 1 . The controller  112  can cause the laser source  102  to emit laser energy at a predefined intensity or power and can cause the actuator  110  to adjust the orientation of the adjustable lens  104  so that the emitted laser beam  106  scans, traces, or otherwise moves along the outline OT-S 1  of the first section S 1 . In this example embodiment, the outline OT-S 1  of the first section S 1  has a rectangular ring shape; accordingly, the laser beam  106  is controlled to scan or trace along this shape. In this way, the excess sidewall material  222 -S 1  forming the tapered sidewalls  220 -S 1  of the first section S 1  can be removed, rendering sidewalls of the first section S 1  formed to specification, e.g., made parallel with the vertical direction V. In some implementations, multiple shots or passes are made along the outline OT-S 1  of the first section S 1  to remove the excess sidewall material  222 -S 1 . 
       FIG. 7  provides a schematic cross-sectional view of the component  200  after the first slice S 1  ( FIG. 2 ) of material has been removed and after the excess sidewall material  222 -S 1  has been removed by laser ablating along the outline OT-S 1  of the first section S 1 . As a result, sidewalls  228 -S 1  forming the first section S 1  of the cavity  210  are now straight or substantially straight without tapering as depicted in  FIG. 7 . The first section S 1  of the cavity  210  is shown fully formed in  FIG. 7 . The first section S 1  is formed to a desired or preselected depth and the sidewalls  228 -S 1  have no or negligible tapering. 
     At ( 306 ), with reference to  FIG. 3 , in some implementations, the method ( 300 ) can include iterating ( 302 ) and ( 304 ) to form subsequent sections of the cavity. For instance, with the first section Si of the cavity  210  fully formed as shown in  FIG. 7 , subsequent sections of the cavity  210  can be formed in the same manner as the first section S 1  was formed. In some implementations, in forming subsequent sections of the cavity  210 , the slice of material removed by laser ablation at ( 302 ) is done so prior to the excess sidewall material being removed by laser ablation at ( 304 ). 
     By way of example, a second section of the cavity  210  can be formed in the same manner as the first section S 1 . As shown in  FIG. 8 , with the first section Si of the cavity  210  formed, the laser ablating action of ( 302 ) can commence once again. Specifically, the controller  112  can cause the laser source  102  to emit laser energy at a predefined intensity or power and can cause the actuator  110  to adjust the orientation of the adjustable lens  104  so that the emitted laser beam  106  moves in a predefined pattern. In this manner, the component  200  can be laser ablated so that the second slice SL 2  of material is removed. 
       FIG. 9  shows the second slice of material SL 2  ( FIG. 8 ) removed so that at least a portion of the second section S 2  of the cavity  210  is formed. As noted above, due to the conical shape of the laser beam  106 , a portion of the laser beam  106  may clip the outer surface  216  and/or the sidewalls  228 -S 1  of the first section S 1  when the laser beam  106  is moved about to remove the second slice of material SL 2 , which results in less energy at the machining surface. Consequently, tapered sidewalls  220 -S 2  result as shown in  FIG. 9 . The tapered sidewalls  220 -S 2  are oriented at an angle with respect to the vertical direction V. 
     With reference to  FIGS. 8, 9, and 10 , after the second slice SL 2  of material has been removed by laser ablating, excess sidewall material  222 -S 2  is removed from the component  200 . The excess sidewall material  222 -S 2  can be removed by laser ablating an outline OT-S 2  of the second section S 2 . Particularly, the controller  112  can cause the laser source  102  to emit laser energy at a predefined intensity or power and can cause the actuator  110  to adjust the orientation of the adjustable lens  104  so that the emitted laser beam  106  moves or scans along the outline OT-S 2  of the second section S 2 . In this way, the excess sidewall material  222 -S 2  forming the tapered sidewalls  220 -S 2  of the second section S 2  can be removed, rendering sidewalls of the second section S 2  formed to specification, e.g., made parallel with the vertical direction V. In some implementations, multiple shots or passes are made along the outline OT-S 2  of the second section S 2  to remove the excess sidewall material  222 -S 2 . 
       FIG. 11  provides a schematic cross-sectional view of the component  200  after the second slice S 2  ( FIG. 8 ) of material has been removed and after the excess sidewall material  222 -S 2  has been removed by laser ablating along the outline OT-S 2  of the second section S 2 . As a result, sidewalls  228 -S 2  forming the second section S 2  of the cavity  210  are now straight or substantially straight without tapering as depicted in  FIG. 11 . The second section S 2  of the cavity  210  is shown fully formed in  FIG. 11 . The second section S 2  is formed to a desired or preselected depth and the sidewalls  228 -S 2  have no or negligible tapering. 
     As noted, ( 302 ) and ( 304 ) of the method ( 300 ) can be iterated to form a number of sections of the cavity. In this example, the process is iterated six times. Accordingly, after the second section S 2  is formed, a third section can be formed, a fourth section can be formed, a fifth section can be formed, and a sixth section can be formed. As will be appreciated, ( 302 ) and ( 304 ) of the method ( 300 ) can be repeated any suitable number of times to achieve the desired geometry of the cavity  210 . In some implementations, ( 302 ) and ( 304 ) can be iterated until at least a portion of the cavity reaches a predetermined depth. In other implementations, ( 302 ) and ( 304 ) can be iterated a predetermined number of times to reach the predetermined depth. The predetermined number of iterations required to achieve the predetermined depth may depend on the intensity of the laser beam during the removal of a given slice and/or during an outline pass, the scan speed, and the predefined pattern used to remove material. In some implementations, all of the formed sections of the cavity have the same thickness or vertical height. In other implementations, the sections need not have the same thickness. For instance, in forming the last section of the cavity  210 , the power or intensity of the laser beam can be adjusted (e.g., reduced), and consequently, the thickness of the last section can be less thick than the other formed sections of the cavity  210 . 
     At ( 308 ), with reference to  FIG. 3 , the method ( 300 ) includes laser ablating the component to remove excess end wall material therefrom to form an end wall of the cavity to a predetermined depth. Notably, the laser ablation of the component at ( 304 ) to remove excess sidewall material section-by-section results in a hump or rounded shape at the blind end  214  of the cavity  210  as shown in  FIG. 12 . Particularly, the laser energy shot along the outline of each section causes more material to be removed around the outline or sidewalls of the cavity  210  than other areas, and as a result, excess end wall material  224  having a rounded shape remains at the blind end  214  of the cavity  210 . Accordingly, a cleanup laser ablation shot or pass is performed to remove the excess end wall material  224  to form an end wall  226  of the cavity  210  to a predetermined depth D 1  as shown in  FIG. 13 . 
     Specifically, the controller  112  can cause the laser source  102  to emit laser energy at a predefined intensity or power and can cause the actuator  110  to adjust the orientation of the adjustable lens  104  so that the emitted laser beam  106  moves or scans along the excess end wall material  224  in a predefined pattern. The laser beam  106  strikes the excess end wall material  224  and removes it from the component  200 . In this way, the end wall  226  of the cavity  210  can be formed to specification, e.g., to the predetermined depth D 1 . As depicted, the sidewalls and the end wall  226  of the resultant cavity  210  are formed to specification with high precision. In some implementations, in laser ablating the component to remove the excess end wall material  224  to form the end wall  226  of the cavity  210  at ( 308 ), an entirety of the end wall  226  is formed to the predetermined depth D 1 , e.g., so that the end wall  226  is flat or substantially flat (e.g., within five degrees (5°) of being perpendicular to the longitudinal length of the cavity  210 ). 
     The predefined pattern used to laser ablate the excess end wall material  224  can be determined based at least in part on the predicted shape of the excess end wall material  224 . The intensity or power of the laser beam  106 , the laser scan speed, and the number of outline laser shots made along the outlines of the sections can be considered in predicting the shape of the excess end wall material  224 . The predefined pattern selected for laser ablating the excess end wall material  224  can be adjusted based at least in part on the predicted shape of the excess end wall material  224 . 
       FIG. 14  provides an example computing system  400  in accordance with an example embodiment of the present subject matter. The controller  112  described herein can include various components and perform various functions of the one or more computing devices  402  of the computing system  400  described below. 
     As shown in  FIG. 14 , the computing system  400  can include one or more computing device(s)  402 . The computing device(s)  402  can include one or more processor(s)  404  and one or more memory device(s)  406 . The one or more processor(s)  404  can include any suitable processing device, such as a microprocessor, microcontroller, integrated circuit, logic device, and/or other suitable processing device. The one or more memory device(s)  406  can include one or more computer-readable media, including, but not limited to, non-transitory computer-readable media, RAM, ROM, hard drives, flash drives, and/or other memory devices. 
     The one or more memory device(s)  406  can store information accessible by the one or more processor(s)  404 , including computer-readable instructions  408  that can be executed by the one or more processor(s)  404 . The instructions  408  can be any set of instructions that when executed by the one or more processor(s)  404 , cause the one or more processor(s)  404  to perform operations, such as any of the operations described herein. For instance, the methods provided herein can be implemented in whole or in part by the computing system  400 . The instructions  408  can be software written in any suitable programming language or can be implemented in hardware. Additionally, and/or alternatively, the instructions  408  can be executed in logically and/or virtually separate threads on processor(s)  404 . The memory device(s)  406  can further store data  410  that can be accessed by the processor(s)  404 . For example, the data  410  can include models, databases, etc. 
     The computing device(s)  402  can also include a network interface  412  used to communicate, for example, with the other components of the laser system  100  (e.g., via a network). The network interface  412  can include any suitable components for interfacing with one or more network(s), including for example, transmitters, receivers, ports, antennas, and/or other suitable components. 
     The technology discussed herein makes reference to computer-based systems and actions taken by and information sent to and from computer-based systems. One of ordinary skill in the art will recognize that the inherent flexibility of computer-based systems allows for a great variety of possible configurations, combinations, and divisions of tasks and functionality between and among components. For instance, processes discussed herein can be implemented using a single computing device or multiple computing devices working in combination. Databases, memory, instructions, and applications can be implemented on a single system or distributed across multiple systems. Distributed components can operate sequentially or in parallel. 
     Although specific features of various embodiments may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the present disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. 
     Further aspects of the invention are provided by the subject matter of the following clauses: 
     A method of laser ablating a component to form a cavity, the method comprising: (a) laser ablating the component to remove a slice of material therefrom so that at least a portion of a section of the cavity is formed; (b) laser ablating the component along an outline of the section to remove excess sidewall material therefrom to form one or more sidewalls of the section; (c) iterating (a) and (b) of the method to form one or more subsequent sections of the cavity; and (d) after iterating at (c), laser ablating the component to remove excess end wall material therefrom to form an end wall of the cavity to a predetermined depth. 
     The method of any preceding clause, wherein laser ablating the component along the outline of the section to remove excess sidewall material therefrom at (b) comprises laser ablating the component along the outline of the section multiple times. 
     The method of any preceding clause, wherein the component is laser ablated along the outline of the section multiple times at (b) prior to the method iterating to (a) to laser ablate the component to remove a subsequent slice of material so that at least a portion of a given one of the one or more subsequent sections of the cavity is formed. 
     The method of any preceding clause, wherein the slice of material is removed by the laser ablating in (a) prior to the excess sidewall material being removed by the laser ablating in (b). 
     The method of any preceding clause, wherein the component is laser ablated along the outline of the section or a given one of the one or more subsequent sections of the cavity at (b) prior to the method iterating to (a) to laser ablate the component to remove a subsequent slice of material so that at least a portion of a next one of the one or more subsequent sections of the cavity is formed. 
     The method of any preceding clause, wherein laser ablating the component along the outline of the section at (b) removes the excess sidewall material therefrom such that the one or more sidewalls forming the section are not tapered. 
     The method of any preceding clause, wherein the excess end wall material, prior to removal by laser ablation at (d), has a rounded shape along a cross section thereof, the rounded shape having a perimeter at a greater depth than a remainder portion of the rounded shape. 
     The method of any preceding clause, wherein (a) and (b) of the method ( 300 ) are iterated at (c) until at least a portion of the cavity reaches a predetermined depth. 
     The method of any preceding clause, wherein (a) and (b) of the method ( 300 ) are iterated at (c) until a predetermined number of iterations have occurred. 
     The method of any preceding clause, wherein the component is a ceramic matrix composite component. 
     The method of any preceding clause, wherein the component is a turbine nozzle for a gas turbine engine and the cavity is a seal slot thereof. 
     The method of any preceding clause, wherein in laser ablating the component to remove the excess end wall material so as to form the end wall of the cavity at (d), an entirety of the end wall is formed to the predetermined depth. 
     A method of laser ablating a turbine nozzle to form a seal slot, the method comprising: (a) laser ablating the turbine nozzle to remove a slice of material therefrom so that at least a portion of a section of the seal slot is formed; (b) laser ablating the turbine nozzle to remove excess sidewall material therefrom to form one or more sidewalls of the section of the seal slot; and (c) laser ablating the turbine nozzle to remove excess end wall material to form an end wall of the seal slot to a predetermined depth. 
     The method of any preceding clause, further comprising: prior to (c), iterating (a) and (b) of the method for one or more subsequent sections of the seal slot. 
     The method of any preceding clause, wherein laser ablating the turbine nozzle at (b) comprises scanning a laser along an outline of the section multiple times. 
     The method of any preceding clause, wherein the turbine nozzle is formed of a ceramic matrix composite material. 
     A non-transitory computer readable medium comprising computer-executable instructions, which, when executed by one or more processors of a controller of a laser system, cause the controller to: (a) cause the laser system to laser ablate a component to remove a slice of material therefrom so that at least a portion of a section of a cavity is formed; (b) cause the laser system to laser ablate the component along an outline of the section to remove excess sidewall material therefrom to form one or more sidewalls of the section; (c) cause the laser system to iterate (a) and (b) for one or more subsequent sections of the cavity; and (d) after iterating at (c), cause the laser system to laser ablate the component to remove excess end wall material therefrom to form an end wall of the cavity to a predetermined depth. 
     The non-transitory computer readable medium of any preceding clause, wherein the slice of material is removed by laser ablation in (a) prior to the excess sidewall material being removed by laser ablation in (b). 
     The non-transitory computer readable medium of any preceding clause, wherein the component is laser ablated along the outline of the section multiple times at (b) prior to iterating to (a) to laser ablate the component to remove a subsequent slice of material so that at least a portion of a given one of the one or more subsequent sections of the cavity is formed. 
     The non-transitory computer readable medium of any preceding clause, wherein the component is a turbine nozzle for a gas turbine engine and the cavity is a seal slot thereof. 
     A system, comprising: a laser source for emitting a laser beam; an adjustable lens for directing the laser beam; an actuator operatively coupled with the adjustable lens; and a controller having one or more processors and one or more memory devices, the controller communicatively coupled with the laser source and the actuator, the one or more processors being configured to: (a) collectively control the laser source and the actuator to laser ablate the component such that a slice of material is removed therefrom thereby forming at least a portion of a section of a cavity; (b) collectively control the laser source and the actuator to laser ablate the component along an outline of the section to remove excess sidewall material therefrom to form one or more sidewalls of the section; (c) cause the laser system to iterate (a) and (b) for one or more subsequent sections of the cavity; and (d) after iterating at (c), collectively control the laser source and the actuator to laser ablate the component to remove excess end wall material to form an end wall of the cavity to a predetermined depth.