US20150367451A1 - High power fiber laser effusion hole drilling apparatus and method of using same - Google Patents
High power fiber laser effusion hole drilling apparatus and method of using same Download PDFInfo
- Publication number
- US20150367451A1 US20150367451A1 US14/309,348 US201414309348A US2015367451A1 US 20150367451 A1 US20150367451 A1 US 20150367451A1 US 201414309348 A US201414309348 A US 201414309348A US 2015367451 A1 US2015367451 A1 US 2015367451A1
- Authority
- US
- United States
- Prior art keywords
- fiber laser
- substantially uniform
- pulse
- laser
- workpiece
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/38—Removing material by boring or cutting
- B23K26/382—Removing material by boring or cutting by boring
- B23K26/389—Removing material by boring or cutting by boring of fluid openings, e.g. nozzles, jets
-
- B23K26/381—
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2101/00—Articles made by soldering, welding or cutting
- B23K2101/001—Turbines
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/02—Iron or ferrous alloys
- B23K2103/04—Steel or steel alloys
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/02—Iron or ferrous alloys
- B23K2103/04—Steel or steel alloys
- B23K2103/05—Stainless steel
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/08—Non-ferrous metals or alloys
- B23K2103/10—Aluminium or alloys thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/08—Non-ferrous metals or alloys
- B23K2103/14—Titanium or alloys thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/18—Dissimilar materials
- B23K2103/26—Alloys of Nickel and Cobalt and Chromium
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/50—Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
- B23K2103/52—Ceramics
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12361—All metal or with adjacent metals having aperture or cut
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
- Y10T428/24273—Structurally defined web or sheet [e.g., overall dimension, etc.] including aperture
Definitions
- the disclosure relates to high power fiber laser devices used for treating aerospace engine materials.
- the disclosure relates to a high power pulsed fiber laser system for drilling holes/passages in aerospace materials and a method of efficient and repetitive drilling of substantially uniform holes using the high power pulsed fiber laser.
- Laser machining including drilling is a fusion process where the base material that is not vaporized or removed during the liquid state resolidifies and becomes a recast layer.
- a recast layer is usually formed from the resolidified molten material at the side walls of the drilled holes. Recast layers are particularly undesirable where drilled holes/passages are traversed by a cooling medium.
- the industry standard requires a recast layer to be about 0.005′′ thick or less. But even this thin of a recast layer is highly undesirable.
- micro-cracks that often extend into the parent material.
- the acceptable width of micro-cracks in the industry is about 0.0016′′. Yet, as miniscule the acceptable width is, such micro-cracks tend to reduce part life.
- Aerospace gas turbines require a large number of small diameter holes ( ⁇ 1 mm) to provide cooling in the turbine blades, nozzle guide vanes, combustion chambers and afterburner. Many thousands of holes are introduced in the surface of these components to allow a film of cooling air to flow over the components when the turbines are operating. Film cooling both extends the life of the component and enables extra performance to be achieved from the engine.
- a typical modem engine will have—100,000 such holes/passages. Drilling these cooling holes by high peak power pulsed Nd—YAG laser is now well established even though the recast and micro-cracking problems remain largely unresolved.
- the advantages include, among others, good coupling of radiation in a 1 ⁇ m wavelength range into part and high pulse energies and peak powers.
- SM Nd—YAG laser is also known to have limitations that in ay not always render its use in the aerospace industry efficient because its performance drifts.
- the power distribution across the laser beam may not always be homogeneous due to a typically used Gaussian beam having a small radius dome-shaped cross-section.
- a pulse width may fluctuate: Equally troubling is the difficulty of controlling peak-to-peak powers of respective subsequent pulses. Accordingly, drilled holes, in addition to typical recast layers and micro-cracks, may have different roundness, consistency and, therefore, may not be of the desired quality which the industry demands.
- a further limitation may relate to a relatively low frequency of pulsing due to limitations in the flash lamps and power supplies which are typically designed for low repetition rates and high peak powers per pulse. As a general rule, trying to increase the repetition rate results in a sharp decrease in maximum power per pulse. With the current demand for higher power and higher repetition rates, currently used Nd—YAG lasers may not meet these requirements.
- Nd—YAG lasers as one of ordinary skill in the laser art knows, have a complex cavity design typically requiring a directly cooled crystal rod that is sealed with O-rings in an enclosed water jacket.
- this dis-closure teaches a workpiece, a method for laser treating the workpiece and an apparatus for practicing the method.
- the apparatus is so configured and the method is so practiced that the body of the workpiece is provided with a plurality of substantially uniform passages having better quality than that offered by the current Nd:YAG technology in the aerospace industry.
- a laser treated workpiece is provided with a discontinuous body defiling a plurality of drilled passages.
- the walls of the drilled passages each are configured so that a recast layer, if formed at all, has a thickness substantially smaller than about 0.005′′ which is the current industry standard.
- the micro-cracks on a resolidified recast layer have a width smaller than 0.0015′′ which is currently the industry standard.
- a high power single mode Yb fiber pulsed laser is utilized to machine a body of workpiece.
- the Yb fiber pulsed laser is configured to laser treat the body so as to drill a plurality of through-going passages such that the wall of each passage may have a recast layer substantially smaller than the current industry standard of about 0.005′′ with at least one microcrack in the recast layer which has a depth of at least about 50% smaller than the current industry standard of about 0.0015′′.
- a method for laser drilling the workpiece is such that the high power single mode Yb fiber pulsed laser is operative to radiate pulses at a pulse repetition rate exceeding 25 Hz, average power of at least 10 kW and peak power exceeding 10 kW.
- the method further enables the Yb fiber pulsed laser to radiate flat-top pulses at a uniform high pulse-to-pulse rate in substantially a fundamental mode.
- the latter is characterized by so selected parameters including, among others, substantially uniform small M 2 value and substantially uniform peak power, that a plurality of uniform passages are of quality superior to that one of passages produced by currently available Nd—YAG lasers.
- FIG. 1 is a diagrammatic view of the disclosed fiber laser system.
- FIG. 2 is a workpiece having a plurality of passages which are provided in accordance with the disclosed method and apparatus practicing the disclosed method.
- FIGS. 3-7 are computer generated shots illustrating respective micro-cracks obtained with differently configured pulses which are emitted by the disclosed apparatus and method.
- FIG. 8 is a chart summarizing the results illustrated in FIGS. 3-7 and comparing these results with industry standard.
- FIGS. 9-13 are respective computer generated shots illustrating recast layers produced under different operating conditions of fiber laser system of FIG. 1 .
- FIG. 14 is a chart illustrating the results shown in. FIGS. 9-13 , respectively, and compared to the industry standard.
- FIG. 1 illustrates a fiber laser drilling system 10 including a high power fiber laser 12 , a beam delivery system 14 typically having beam guiding optics which guides the laser output beam to a laser head 16 .
- the latter is operative to focus the beam on the desired location of a workpiece 18 and typically has up to twelve (12) degrees of freedom so as to allow for convenient displacement of the head and workpiece relative to one another along a predetermined path over a plurality of locations corresponding to respective passages to be drilled as provided by X product available from Y company from (Z address)
- the fiber laser 12 includes a plurality of separate laser modules each provided with an Ytterbium (“Yb”) oscillator operative to output at about 500 W or higher.
- Yb Ytterbium
- MOPA master oscillator and power amplifier
- the laser is a model YLRxxxx available from IPG Photonics Corporation, Oxford, Mass.
- the Yb fiber laser 12 is configured to emit square-shaped pulses at a repetition rate between about 25 Hz and about 50 Hz in low multimode (“MM”) radiation at wavelengths around 1070 nm.
- MM low multimode
- the system light has a stable, low beam product parameter (“BPP”) which ranges from about 3 to about 5 and an M 2 value roughly around 10.
- Yb fiber laser 12 within the above-disclosed ranges are so selected that all of the drilled passages 20 are clean, free of surface splatter and have substantially uniform diameter, taper, passage entrance and clean passage exit.
- the pulses have a stable uniform pulse-to-pulse rate, uniform amplitude or peak power and uniform square pulse shape all leading to the formation of substantially uniform passages.
- FIG. 2 Provides a workpiece 18 with oval passages having a major axis of x and a minor axis of diameter at the top surface with a standard deviation of z. The area of the surface removed by the oval equaling Aoval.
- system 10 which is configured with the above-listed parameters, produces a microcrack 24 on a wall of passage 20 in workpiece 18 .
- the pulse width in this experiment is about 0.5 milliseconds.
- This experiment shown in FIG. 8 as 1 results microcrack 24 having a width of about 0.0004′′.
- system 10 is operative to output pulses each having a pulse width of 1 millisecond.
- microcrack 24 is produced with about 0.0006′′ width.
- FIG. 5 illustrates the results of a pulse width of about 2 milliseconds.
- the result of this experiment is referenced by numeral 3 in FIG. 8 and includes the width of microcrack 24 of about 0.001′′.
- FIG. 6 illustrates the results produced by drilling workpiece 18 with laser system 10 operative to emit square pulses each with pulse width of about 3 milliseconds.
- 1 bis experiment corresponds to reference numeral 4 in FIG. 8 and results in about 0.0008′′ width.
- FIG. 7 illustrates microcrack 24 formed with parameters which are somewhat different from previous four experiments.
- system 10 fires a single 10 millisecond pulse, which is not available from Nd—YAG lasers.
- the result 0.0002′′ width, is substantially the same as in case of the shortest pulse width of 0.5 milliseconds in experiment 1 .
- the drill time per passage in this experiment is about 0.05 which is substantially shorter than 0.6 milliseconds needed in previous experiments.
- FIG. 8 dearly illustrates the advantages of using system of the present disclosure. Compared to aerospace standard of about 0.014′′ denoted by reference numeral 6 , even the worst result obtained in experiment 3 by disclosed fiber laser system 10 is considerably better than the standard.
- laser system 10 configured with the same parameters as disclosed in reference to FIGS. 3-8 also shows a substantially improved recast layer's thickness compared to the aerospace industry's standard.
- FIG. 14 illustrates the results of five experiments referenced by respective numerals 1 , 2 , 3 , 4 and 5 and reference numeral 6 being the industry standard.
- first three experiments with respective pulse widths 0.5, 1.0 and 2.0 milliseconds produced about 0.0018′′, 0.0022′′ and 0.0025′′ thick recast layers, respectively.
- the fourth setting with a 3.0 millisecond pulse width resulted in a recast layer having a thickness about 0.0022′′. All of the above experiments produced the respective results, recast layer thickness lower than the standard thickness of about 0.005′′ corresponding to the right end column 6 .
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Mechanical Engineering (AREA)
- Laser Beam Processing (AREA)
Abstract
A fiber laser-treated workpiece is configured with a body having a discontinuous surface which defines a plurality of spaced through-going passages so that each passage is delimited by a peripheral layer having a surface characteristic which includes a recast layer or one or more microcracks or a combination thereof. The passages are provided by a high power Yb fiber laser operating in a pulsed regime and configured to output either a single pulse per an entire passage or a train of pulses per the passage. The Yb fiber laser is so configured that, if formed, the recast layer and micro-crack each are smaller than respective standards in an airspace industry.
Description
- 1. Field of the Disclosure
- The disclosure relates to high power fiber laser devices used for treating aerospace engine materials. In particular, the disclosure relates to a high power pulsed fiber laser system for drilling holes/passages in aerospace materials and a method of efficient and repetitive drilling of substantially uniform holes using the high power pulsed fiber laser.
- 2. Prior Art Discussion
- Laser machining including drilling is a fusion process where the base material that is not vaporized or removed during the liquid state resolidifies and becomes a recast layer. In the case of the conventional laser drilling process, a recast layer is usually formed from the resolidified molten material at the side walls of the drilled holes. Recast layers are particularly undesirable where drilled holes/passages are traversed by a cooling medium. The industry standard requires a recast layer to be about 0.005″ thick or less. But even this thin of a recast layer is highly undesirable.
- Rapid solidification of processed metal results in micro-cracks that often extend into the parent material. The acceptable width of micro-cracks in the industry is about 0.0016″. Yet, as miniscule the acceptable width is, such micro-cracks tend to reduce part life.
- Aerospace gas turbines require a large number of small diameter holes (<1 mm) to provide cooling in the turbine blades, nozzle guide vanes, combustion chambers and afterburner. Many thousands of holes are introduced in the surface of these components to allow a film of cooling air to flow over the components when the turbines are operating. Film cooling both extends the life of the component and enables extra performance to be achieved from the engine. A typical modem engine will have—100,000 such holes/passages. Drilling these cooling holes by high peak power pulsed Nd—YAG laser is now well established even though the recast and micro-cracking problems remain largely unresolved.
- As one of ordinary skill in the laser arts knows, every type of laser has its advantages and disadvantages in the context of specific purposes, such as providing aerospace components with a plurality of holes. Referring specifically to Nd—YAG lasers, the advantages include, among others, good coupling of radiation in a 1 μm wavelength range into part and high pulse energies and peak powers.
- However, a single mode (“SM”) Nd—YAG laser is also known to have limitations that in ay not always render its use in the aerospace industry efficient because its performance drifts. For example, the power distribution across the laser beam may not always be homogeneous due to a typically used Gaussian beam having a small radius dome-shaped cross-section. Furthermore, a pulse width may fluctuate: Equally troubling is the difficulty of controlling peak-to-peak powers of respective subsequent pulses. Accordingly, drilled holes, in addition to typical recast layers and micro-cracks, may have different roundness, consistency and, therefore, may not be of the desired quality which the industry demands.
- A further limitation may relate to a relatively low frequency of pulsing due to limitations in the flash lamps and power supplies which are typically designed for low repetition rates and high peak powers per pulse. As a general rule, trying to increase the repetition rate results in a sharp decrease in maximum power per pulse. With the current demand for higher power and higher repetition rates, currently used Nd—YAG lasers may not meet these requirements.
- Furthermore, traditional Nd—YAG lasers, as one of ordinary skill in the laser art knows, have a complex cavity design typically requiring a directly cooled crystal rod that is sealed with O-rings in an enclosed water jacket. There are many extra-cavity optic elements required to correct for thermal distortion in the Nd:YAG rod. All these elements must be properly maintained, which requires a complex controlling means; otherwise, thermal instability inside and outside the cavity may result in noticeable differences in beam output characteristics leading to drilled passages with markedly different recast thicknesses and therefore poor uniformity.
- A need therefore exists for a laser treated workpiece provided with a plurality of uniform passages so that an average recast layer, if formed at all, is substantially thinner than the industry standard.
- Another need exists for a laser treated workpiece provided with a plurality of uniform passages so that base crack depth levels in the components are lower than the industry standard. Another need exists for a fiber laser system configured so that a plurality of uniform passages, laser drilled in a workpiece, have respective peripheries formed with minimal recast layers and microcracks which have respective levels lower than the industry established standards.
- Another need exists for a method of laser drilling a plurality of passages in a workpiece so that recast layer and base micro-crack levels, if formed on peripheries of respective passages, are substantially lower than respective industry standards.
- Another need exists for a method of laser drilling a plurality of passages in a workpiece so that the uniformity of the diameter of the passage diameters are substantially lower than respective industry standards, preferably lower than xxx standard deviation.
- The above and other needs are met by the teaching provided by the present invention. In particular, this dis-closure teaches a workpiece, a method for laser treating the workpiece and an apparatus for practicing the method. The apparatus is so configured and the method is so practiced that the body of the workpiece is provided with a plurality of substantially uniform passages having better quality than that offered by the current Nd:YAG technology in the aerospace industry.
- In accordance with one aspect of the disclosure, a laser treated workpiece is provided with a discontinuous body defiling a plurality of drilled passages. The walls of the drilled passages each are configured so that a recast layer, if formed at all, has a thickness substantially smaller than about 0.005″ which is the current industry standard. The micro-cracks on a resolidified recast layer have a width smaller than 0.0015″ which is currently the industry standard.
- In accordance with a further aspect of the disclosure, a high power single mode Yb fiber pulsed laser is utilized to machine a body of workpiece. The Yb fiber pulsed laser is configured to laser treat the body so as to drill a plurality of through-going passages such that the wall of each passage may have a recast layer substantially smaller than the current industry standard of about 0.005″ with at least one microcrack in the recast layer which has a depth of at least about 50% smaller than the current industry standard of about 0.0015″.
- In accordance with still a further aspect of the disclosure, a method for laser drilling the workpiece is such that the high power single mode Yb fiber pulsed laser is operative to radiate pulses at a pulse repetition rate exceeding 25 Hz, average power of at least 10 kW and peak power exceeding 10 kW. The method further enables the Yb fiber pulsed laser to radiate flat-top pulses at a uniform high pulse-to-pulse rate in substantially a fundamental mode. The latter is characterized by so selected parameters including, among others, substantially uniform small M2 value and substantially uniform peak power, that a plurality of uniform passages are of quality superior to that one of passages produced by currently available Nd—YAG lasers.
- The above and other features and advantages of the disclosed apparatus, method and product will become more readily apparent from the specific description accompanied by the following drawings, in which:
-
FIG. 1 is a diagrammatic view of the disclosed fiber laser system. -
FIG. 2 is a workpiece having a plurality of passages which are provided in accordance with the disclosed method and apparatus practicing the disclosed method. -
FIGS. 3-7 are computer generated shots illustrating respective micro-cracks obtained with differently configured pulses which are emitted by the disclosed apparatus and method. -
FIG. 8 is a chart summarizing the results illustrated inFIGS. 3-7 and comparing these results with industry standard. -
FIGS. 9-13 are respective computer generated shots illustrating recast layers produced under different operating conditions of fiber laser system ofFIG. 1 . -
FIG. 14 is a chart illustrating the results shown in.FIGS. 9-13 , respectively, and compared to the industry standard. - Reference will now be made in detail to several embodiments of the invention that are illustrated in the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps. Certain drawings are in simplified form and are not to precise scale. The word “couple” and similar terms do not necessarily denote direct and immediate connections, but also include connections through intermediate elements or devices.
-
FIG. 1 illustrates a fiberlaser drilling system 10 including a highpower fiber laser 12, abeam delivery system 14 typically having beam guiding optics which guides the laser output beam to alaser head 16. The latter is operative to focus the beam on the desired location of aworkpiece 18 and typically has up to twelve (12) degrees of freedom so as to allow for convenient displacement of the head and workpiece relative to one another along a predetermined path over a plurality of locations corresponding to respective passages to be drilled as provided by X product available from Y company from (Z address) - The
fiber laser 12 includes a plurality of separate laser modules each provided with an Ytterbium (“Yb”) oscillator operative to output at about 500 W or higher. The configuration may be altered by utilizing known to one of ordinary skill in the laser art master oscillator and power amplifier (“MOPA”) schematics. Preferably, the laser is a model YLRxxxx available from IPG Photonics Corporation, Oxford, Mass. - The cumulative output of the modules—system light—can easily reach a multi-kW level ranging between about 10 kW and about 20 kW and higher. The
Yb fiber laser 12 is configured to emit square-shaped pulses at a repetition rate between about 25 Hz and about 50 Hz in low multimode (“MM”) radiation at wavelengths around 1070 nm. The system light has a stable, low beam product parameter (“BPP”) which ranges from about 3 to about 5 and an M2 value roughly around 10. - Referring to
FIG. 2 , specific parameters ofYb fiber laser 12 within the above-disclosed ranges are so selected that all of the drilledpassages 20 are clean, free of surface splatter and have substantially uniform diameter, taper, passage entrance and clean passage exit. In other words, the pulses have a stable uniform pulse-to-pulse rate, uniform amplitude or peak power and uniform square pulse shape all leading to the formation of substantially uniform passages. -
FIG. 2 . Provides aworkpiece 18 with oval passages having a major axis of x and a minor axis of diameter at the top surface with a standard deviation of z. The area of the surface removed by the oval equaling Aoval. - The foregoing results required by many industries including the aerospace industry have been achieved with the above-disclosed laser
system treating workpiece 18 which is made from aluminum, ceramic, metallo ceramics, nickel and nickel alloys including but not limited to Hastelloy® variants, Inconel® variants including Inconel® 625, Inconel® 718, Mar-M variants, Single Crystal, carbon steels, stainless steels, Titanium and/or Waspalloy® variants and various oxides, alloys and combinations of these. - Referring to
FIGS. 3-7 , the importance of disclosedsystem 10 ofFIG. 1 becomes readily apparent from experimental results including the formations and dimensions of recast layers and micro cracks inworkpiece 18 which may be configured, without any limitation, as turbine blades, nozzle, guide vanes, combustion chambers and afterburner and others. The following parameters are common to all of the experiments shown in respectiveFIGS. 3-6 and includelaser system 10 outputting fifteen (15) square pulses at a repetition rate 25 Hz and with at 15 kW peak power per each pulse. - Despite different pulse with, as disclosed below, an average time necessary for drilling the passage is about 6 seconds. What were the materials?
- Referring specifically to
FIGS. 3 and 8 ,system 10, which is configured with the above-listed parameters, produces amicrocrack 24 on a wall ofpassage 20 inworkpiece 18. The pulse width in this experiment is about 0.5 milliseconds. This experiment shown inFIG. 8 as 1 results microcrack 24 having a width of about 0.0004″. - Referring specifically to
FIGS. 4 and 8 ,system 10 is operative to output pulses each having a pulse width of 1 millisecond. Denoted bynumeral reference 2 inFIG. 8 ,microcrack 24 is produced with about 0.0006″ width. -
FIG. 5 illustrates the results of a pulse width of about 2 milliseconds. The result of this experiment is referenced bynumeral 3 inFIG. 8 and includes the width ofmicrocrack 24 of about 0.001″. -
FIG. 6 illustrates the results produced by drillingworkpiece 18 withlaser system 10 operative to emit square pulses each with pulse width of about 3 milliseconds. 1 bis experiment corresponds to reference numeral 4 inFIG. 8 and results in about 0.0008″ width. -
FIG. 7 illustratesmicrocrack 24 formed with parameters which are somewhat different from previous four experiments. In particular, instead of a pulse train,system 10 fires a single 10 millisecond pulse, which is not available from Nd—YAG lasers. As can be seen inFIG. 8 , underreference numeral 5, the result, 0.0002″ width, is substantially the same as in case of the shortest pulse width of 0.5 milliseconds inexperiment 1. However, in contrast to all previous settings, the drill time per passage in this experiment is about 0.05 which is substantially shorter than 0.6 milliseconds needed in previous experiments. -
FIG. 8 dearly illustrates the advantages of using system of the present disclosure. Compared to aerospace standard of about 0.014″ denoted byreference numeral 6, even the worst result obtained inexperiment 3 by disclosedfiber laser system 10 is considerably better than the standard. - Referring now to
FIGS. 9-14 ,laser system 10 configured with the same parameters as disclosed in reference toFIGS. 3-8 also shows a substantially improved recast layer's thickness compared to the aerospace industry's standard. - In particular, the same five experiments corresponding to respective pulse widths 0.5, 1.0, 2.0, 3.0 and single pulse of 10 milliseconds have been conducted and resulted in a recast
layer 26 clearly seen in respectiveFIGS. 9-13 .FIG. 14 illustrates the results of five experiments referenced byrespective numerals reference numeral 6 being the industry standard. - As can be seen from
FIG. 14 , first three experiments with respective pulse widths 0.5, 1.0 and 2.0 milliseconds produced about 0.0018″, 0.0022″ and 0.0025″ thick recast layers, respectively. The fourth setting with a 3.0 millisecond pulse width resulted in a recast layer having a thickness about 0.0022″. All of the above experiments produced the respective results, recast layer thickness lower than the standard thickness of about 0.005″ corresponding to theright end column 6. - The last experiment,
number 5, with a single 10 millisecond pulse width again showed to be advantages in many respects and had substantially the same result, 0.0018″, asexperiment 1 with the shortest pulse width. - All the results were obtained in a certified Metallurgical laboratory and are correlated to the configuration and use of a high power MM Yb fiber laser of the present disclosure. Having described at least one of the preferred embodiments of the present disclosure with reference to the accompanying drawings, it will be apparent to those skills that the invention is not limited to those precise embodiments, and that various modifications and variations can be made in the presently disclosed workpiece, method and system for laser drilling of aerospace material. It is believed that with higher powers soon to be available, various pulse widths, shot counts and maybe even modified pulse shapes, the results may be even more encouraging Thus, it is intended that the present disclosure cover the modifications and variations of this disclosure provided they come within the scope of the appended claims.
Claims (21)
1. A fiber laser-treated workpiece comprising a discontinued body defining a plurality of spaced through-going passages, each passage being delimited by a peripheral layer having a surface characteristic which includes a recast layer and one or more micro cracks, wherein, if formed, the recast layer depth and micro crack width each are smaller than respective standards in an airspace industry.
2. The fiber laser-treated workpiece of claim 1 , wherein the industry standards for a recast layer thickness and a micro-crack width are respectively 0.005″ and 0.0015″.
3. The fiber laser-treated workpiece of claim 1 , wherein the thickness of the recast layer varies between about 0.0015″ and about 0.0025″ and a micro-crack width varies between about 0.0002″ and about 0.001″.
4. The fiber laser-treated workpiece of claim 1 , wherein the body made from material selected from the group consisting of aluminum, ceramics, metallo-ceramics, nickel alloys, stainless steels, titanium and a combination thereof.
5. The fiber laser-treated workpiece of claim 1 , wherein the body has a configuration selected from the group consisting of turbine blades, nozzle, guide vanes, combustion chambers and afterburner.
6. The fiber laser-treated workpiece of claim 1 , wherein the spaced passages have respective substantially uniform diameters and tapers, the peripheral layers each being free from splatter and having clean and substantially uniform exit and an entrance free from irregularities.
7. The fiber laser-treated workpiece of claim 6 , the spaced passages having substantially uniform openings having a standard deviation less than x.
8. A method of drilling a workpiece, comprising:
controllably displacing the workpiece and single mode high power fiber laser relative to one another among a plurality of predetermined locations along a path; and
periodically firing the fiber laser at each of the locations, thereby outputting at least one pulse incident on the location so as to drill a plurality of through-going spaced passages in the workpiece, the at least one pulse having optical characteristics selected so that a recast layer, if formed on a periphery defining a passage, and one or more micro cracks, if formed in the recast layer, have a thickness and a width, respectively, smaller than respective standards for an aerospace industry.
9. The method of claim 8 , wherein the periodic :firing of the fiber laser includes outputting single one pulse per each location, the one pulse being shaped and configured to drill an entire passage.
10. The method of claim 9 , wherein one pulse at each location has a pulse width of about 10 milliseconds, a square shape, a peak power varying between 6 kW and about 20 kW.
11. The method of claim 8 , wherein the periodic firing of the fiber laser includes outputting a plurality of pulses per each location at a repetition rate varying between about 25 Hz and about 50 Hz.
12. The method of claim 11 , wherein the outputting of the pulses includes configuring uniform square pulses each having a pulse width between 0.5 to about 3 milliseconds.
13. The method of claim 12 , wherein the outputting of the uniform pulses occurs in substantially a fundamental mode having substantially uniform parameters which include an M2 value, focal point, spot size, and peak power ranging between about 6 kW and about 20 kW.
14. The method of claim 8 , wherein the standards for the thickness and width are about 0.0015″ and about 0.0005″, respectively.
15. A laser system for drilling a body of a workpiece, the laser system comprising a high power Yb fiber laser operative to emit a plurality of discreet pulses incident on selected locations on the body and configured to provide a plurality of through-going and substantially uniform spaced passages at respective locations, the passage each being defined by a periphery, the pulses each having parameters selected so that a recast layer, if formed on the periphery, and one or more microcracks, if formed in the recast layer, have a thickness and a width, respectively, smaller than respective standards for an aerospace industry.
16. The laser system of claim 15 , wherein the standards for a recast layer thickness and a micro-crack width are respectively 0.005″ and 0.0015″.
17. The laser system of claim 15 , wherein the fiber laser is so configured that a single discreet pulse has parameters sufficient to drill an entire passage.
18. The laser system of claim 17 , wherein the single discreet pulse has the parameters including a square shape, pulse width of at least 10 milliseconds, and a peak power of at least . . . , the parameters are so selected that the peripheries of the respective passages are tapered at a substantially uniform angle, have a substantially uniform diameter, free form splatter and have a clean and substantially uniform exit and an entrance free from irregularities.
19. The laser system of claim 15 , wherein the fiber laser is configured to emit a train of the discreet pulses for a single passage, the pulses each having substantially uniform parameters including a square shape and a pulse width varying between about 0.5 to about 3 milliseconds, the parameters being so selected that the peripheries of the respective passages are tapered at a substantially uniform angle, have a substantially uniform diameter, free from splatter and have a clean and substantially uniform exit and an entrance free from irregularities.
20. The laser system of claim 15 , wherein the fiber laser is operative to output the discreet pulses at a repetition rate between about 25 and about 50 Hz and a peak power varying between about 6 kW and 20 kW.
21. The laser system of claim 15 , wherein the high power single mode Yb fiber laser is configured with a plurality of modules optically coupled to one another and each having an Yb doped oscillator output radiation with a substantially uniform M2 value, substantially uniform focal point and spot size, and substantially uniform peak power ranging between about 6 kW and about 20 kW.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/309,348 US20150367451A1 (en) | 2014-06-19 | 2014-06-19 | High power fiber laser effusion hole drilling apparatus and method of using same |
US15/865,370 US10857627B2 (en) | 2011-12-20 | 2018-01-09 | High power fiber laser effusion hole drilling apparatus and method of using same |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/309,348 US20150367451A1 (en) | 2014-06-19 | 2014-06-19 | High power fiber laser effusion hole drilling apparatus and method of using same |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/865,370 Division US10857627B2 (en) | 2011-12-20 | 2018-01-09 | High power fiber laser effusion hole drilling apparatus and method of using same |
Publications (1)
Publication Number | Publication Date |
---|---|
US20150367451A1 true US20150367451A1 (en) | 2015-12-24 |
Family
ID=54868835
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/309,348 Abandoned US20150367451A1 (en) | 2011-12-20 | 2014-06-19 | High power fiber laser effusion hole drilling apparatus and method of using same |
US15/865,370 Active 2035-03-17 US10857627B2 (en) | 2011-12-20 | 2018-01-09 | High power fiber laser effusion hole drilling apparatus and method of using same |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/865,370 Active 2035-03-17 US10857627B2 (en) | 2011-12-20 | 2018-01-09 | High power fiber laser effusion hole drilling apparatus and method of using same |
Country Status (1)
Country | Link |
---|---|
US (2) | US20150367451A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170129050A1 (en) * | 2015-11-06 | 2017-05-11 | The Boeing Company | Edge preparation for laser welding |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11254171A (en) * | 1998-03-13 | 1999-09-21 | Mitsubishi Electric Corp | Laser beam machining device for wiring board |
US6229113B1 (en) * | 1999-07-19 | 2001-05-08 | United Technologies Corporation | Method and apparatus for producing a laser drilled hole in a structure |
US20100098112A1 (en) * | 2008-10-21 | 2010-04-22 | Gapontsev Valentin P | Method and apparatus for preventing distortion of powerful fiber-laser systems by backreflected signals |
US20100102045A1 (en) * | 2007-02-13 | 2010-04-29 | Lasag Ag | Method of cutting parts to be machined using a pulsed laser |
US20150190882A1 (en) * | 2012-08-09 | 2015-07-09 | Rofin-Lasag Ag | Assembly for processing work pieces with a laser beam |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2241594B (en) * | 1990-03-02 | 1993-09-01 | Rolls Royce Plc | Improvements in or relating to laser drilling of components |
JPH10242617A (en) * | 1997-02-28 | 1998-09-11 | Murata Mfg Co Ltd | Method and apparatus for processing ceramic green sheet |
JP4784406B2 (en) * | 2006-06-13 | 2011-10-05 | 住友電気工業株式会社 | Fiber laser apparatus and laser processing method |
CN104039496B (en) * | 2011-12-20 | 2017-03-08 | Ipg光子公司 | High power fibre laser cascading water hole drill aperture apparatus and the method using this device |
KR102176312B1 (en) * | 2012-06-22 | 2020-11-09 | 아이피지 포토닉스 코포레이션 | Laser drilling method and system for producing shaped holes |
-
2014
- 2014-06-19 US US14/309,348 patent/US20150367451A1/en not_active Abandoned
-
2018
- 2018-01-09 US US15/865,370 patent/US10857627B2/en active Active
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH11254171A (en) * | 1998-03-13 | 1999-09-21 | Mitsubishi Electric Corp | Laser beam machining device for wiring board |
US6229113B1 (en) * | 1999-07-19 | 2001-05-08 | United Technologies Corporation | Method and apparatus for producing a laser drilled hole in a structure |
US20100102045A1 (en) * | 2007-02-13 | 2010-04-29 | Lasag Ag | Method of cutting parts to be machined using a pulsed laser |
US20100098112A1 (en) * | 2008-10-21 | 2010-04-22 | Gapontsev Valentin P | Method and apparatus for preventing distortion of powerful fiber-laser systems by backreflected signals |
US20150190882A1 (en) * | 2012-08-09 | 2015-07-09 | Rofin-Lasag Ag | Assembly for processing work pieces with a laser beam |
Non-Patent Citations (4)
Title |
---|
Aragaw, "Application of Optical Emission Spectroscopy Method for Characterization of Laser Micro Drilling", 12/2010, Master of Science thesis of Polo Regionale di Lecco (Matr. N, 737578). * |
Biffi et al., "Spatter Reduction in nanosecond fibre laser drilling using an innovative nozzle", 07/2012, Int. Journal Advanced Manufacturing Technology, Volume 66, pages 1231-1245. * |
machine translation of Japan Patent document No. 11-254,171, 10/2017. * |
Waurzyniak, "Lasers drill Precision Holes Quickly", 11/2013, ManufacturingEngineeringMedia.com, pages 69-77. * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20170129050A1 (en) * | 2015-11-06 | 2017-05-11 | The Boeing Company | Edge preparation for laser welding |
US11311969B2 (en) * | 2015-11-06 | 2022-04-26 | The Boeing Company | Edge preparation for laser welding |
Also Published As
Publication number | Publication date |
---|---|
US10857627B2 (en) | 2020-12-08 |
US20180141165A1 (en) | 2018-05-24 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7324571B2 (en) | Methods and systems for laser processing a workpiece and methods and apparatus for controlling beam quality therein | |
US9956646B2 (en) | Multiple-beam laser processing using multiple laser beams with distinct wavelengths and/or pulse durations | |
JP5535423B2 (en) | How to cut stainless steel with fiber laser | |
JP6698701B2 (en) | Laser processing apparatus and method and optical parts thereof | |
US20180126488A1 (en) | Fibre optic laser machining equipment for etching grooves forming incipient cracks | |
US7671296B2 (en) | Nose-piece for a laser-beam drilling or machining head | |
JP2009525189A (en) | A cutting method using a laser having at least one ytterbium-based fiber, wherein at least the power of the laser source, the focused beam diameter and the Q value of the beam are controlled | |
EP2956270A1 (en) | Laser-induced gas plasma machining | |
US10857627B2 (en) | High power fiber laser effusion hole drilling apparatus and method of using same | |
US6642476B2 (en) | Apparatus and method of forming orifices and chamfers for uniform orifice coefficient and surface properties by laser | |
EP3307473B1 (en) | Laser drilling method and system with laser beam energy modification to reduce back-wall strikes during laser drilling | |
EP2794179B1 (en) | High power fiber laser effusion hole drilling apparatus and method of using same | |
Westphäling | Pulsed Fiber Lasers from ns to ms range and their applications | |
US6600132B2 (en) | Method and apparatus to generate orifice disk entry geometry | |
Dausinger | Drilling of high quality micro holes | |
Shiner | Fiber lasers for material processing | |
US6603095B2 (en) | Apparatus and method of overlapping formation of chamfers and orifices by laser light | |
US6635847B2 (en) | Method of forming orifices and chamfers by collimated and non-collimated light | |
EP2864077B1 (en) | Laser drilling method and system for producing shaped holes | |
JP2021159929A (en) | Concrete surface treatment method and laser-treated concrete surface | |
Woratz et al. | Drilling of high-aspect holes with microsecond pulsed high-power Nd: YAG and long-pulse single mode lasers | |
Graham et al. | Technical advantages of disk laser technology in short and ultrashort pulse processes | |
WO2023172533A1 (en) | Dynamically controlled laser drilling system and method for producing circular holes | |
Harris et al. | Laser cutting of thick steel plate | |
Washko et al. | Laser drilling with gated high power fiber lasers |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |