Systems and methods for separating continuous glass tubing into individual lengths of glass tubes

Abstract

A method for separating continuous glass tubing, the method comprising: passing the continuous glass tubing through a laser system operable to produce a laser beam; forming a scribe line in the continuous glass tubing by focusing the laser beam to be incident on a surface of the continuous glass tubing; and separating the continuous glass tubing along the scribe line to produce a glass tube having a fixed length. The laser system is configured to cause the laser beam to be incident on less than half of a circumference of the continuous glass tubing.

Description

SYSTEMS AND METHODS FOR SEPARATING CONTINUOUS GLASS TUBING INTO INDIVIDUAL LENGTHS OF GLASS TUBESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. §119 of U.S. Provisional Application Serial No. 63 / 534,230 filed on August 23, 2023, the content of which is relied upon and incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present specification generally relates to methods, apparatuses, and systems for continuously producing glass tubing, in particular, methods, apparatuses, and systems for separating a continuous glass tube into lengths of glass tubing.BACKGROUND

[0003] Historically, glass has been used to produce a variety of articles. In particular, because of its hermeticity, optical clarity, and excellent chemical durability relative to other materials, glass has been a preferred material for pharmaceutical applications, including, without limitation, vials, syringes, ampoules, cartridges, jars, and other glass articles. Production of these articles from glass starts with providing glass tubing that may subsequently be formed and separated into a plurality of the glass articles. Specifically, the glass used in pharmaceutical packaging must have adequate mechanical and chemical durability so as to not affect the stability of the pharmaceutical formulations contained therein. Glasses having suitable chemical durability include those glass compositions within the ASTM standard ‘Type IA’ and ‘Type IB’ glass compositions, which have a proven history of chemical durability. The glass tubes used as the starting material for producing glass articles are produced from a continuous process, such as a Danner or Velio process, for producing a continuous hollow glass cylinder. The continuous hollow glass cylinder is annealed and cut into sections of glass tubes of roughly the same length by a continuous cutter.SUMMARY

[0004] Accordingly, a need exists for methods, apparatuses, and systems for continuously producing glass tubes or glass rods, in particular, for methods, apparatuses, and systems for separating a continuous glass tube into a plurality of lengths of glass tube.

[0005] According to a first aspect of the present disclosure, a method for separating continuous glass tubing comprises: passing the continuous glass tubing through a laser system operable to produce a laser beam; forming a scribe line in the continuous glass tubing by focusing the laser beam to be incident on a surface of the continuous glass tubing, wherein the laser system is configured to cause the laser beam to be incident on less than half of a circumference of the continuous glass tubing; and separating the continuous glass tubing along the scribe line to produce a glass tube having a fixed length.

[0006] A second aspect may include the first aspect, wherein passing the continuous glass tubing through the laser system comprises moving the continuous glass tubing in a direction parallel to a center axis A of the continuous glass tubing.

[0007] A third aspect may include the second aspect, wherein moving the continuous glass tubing in the direction parallel to the center axis A of the continuous glass tubing comprises pulling the continuous glass tubing from a glass tube forming apparatus through the laser system using a tube puller.

[0008] A fourth aspect may include any one of the first through third aspects, wherein the scribe line is formed over less than 180 degrees of the circumference of the continuous glass tubing.

[0009] A fifth aspect may include any one of the first through fourth aspects, wherein a depth of the scribe line varies with angular position on the surface of the continuous glass tubing.

[0010] A sixth aspect may include any one of the first through fifth aspects, wherein the scribe line comprises a scribe line length Lsgreater than or equal to 0.001 times di and less than or equal to di, where di is an outer diameter of the continuous glass tubing.

[0011] A seventh aspect may include any one of the first through sixth aspects, wherein the laser beam comprises a wavelength from about 2 pm to about 12 pm.

[0012] A eighth aspect may include any one of the first through seventh aspects, wherein the laser beam comprises a wavelength of 1064 nm, 532 nm, 355 nm, or 266 nm.

[0013] A ninth aspect may include any one of the first through eighth aspects, wherein the laser system comprises a pulsed laser assembly and the laser beam is an ultrashort pulsed laser.

[0014] A tenth aspect may include any one of the first through ninth aspects, further comprising transforming the laser beam into a Bessel beam defining a laser beam focal line,wherein the scribe line comprises a plurality of perforations formed in the continuous glass tubing by the laser beam focal line.

[0015] A eleventh aspect may include any one of the first through ninth aspects, further comprising transforming the laser beam into a Gaussian beam defining a laser beam focal point, wherein the scribe line comprises an ablated trench formed by the laser beam focal point.

[0016] A twelfth aspect may include the eleventh aspect, further comprising forming the ablated trench to have a trench width Tw greater than or equal to 20 pm and less than or equal to 50 pm.

[0017] A thirteenth aspect may include any one of the first through seventh, eleventh, or twelfth aspects, wherein the laser system comprises a laser source, and wherein the laser source is a CO2 laser.

[0018] A fourteenth aspect may include any one of the eleventh or thirteenth aspects, further comprising forming the ablated trench to have a trench width Tw greater than or equal to 100 pm and less than or equal to 300 pm.

[0019] A fifteenth aspect may include any one of the first through thirteenth aspects, wherein the laser beam comprises a beam output power greater than or equal to 40 W and less than or equal to 600 W.

[0020] A sixteenth aspect may include any one of the first through seventh or eleventh through fifteenth aspects, wherein the laser beam comprises a wavelength greater than or equal to 9.2 pm and less than or equal to 11.2 pm.

[0021] A seventeenth aspect may include any one of the first through sixteenth aspects, further comprising passing the laser beam through a cylindrical lens that converts the laser beam into a focused line, wherein the laser beam is static.

[0022] A eighteenth aspect may include any one of the first through sixteenth aspects, further comprising scanning the laser beam across the surface of the continuous glass tubing with a laser beam steering device.

[0023] A nineteenth aspect may include the eighteenth aspect, wherein scanning the laser beam across the surface of the continuous glass tubing with the laser beam steering device comprises controlling movement of the laser beam using a mirror galvanometer or a polygon mirror.

[0024] A twentieth aspect may include any one of the eighteenth or nineteenth aspects, wherein scanning the laser beam across the surface of the continuous glass tubing comprises scanning the laser beam at an angle with respect to a center axis A of the continuous glass tubing such that the scribe line is formed perpendicular to the center axis A of the continuous glass tubing.

[0025] A twenty-first aspect may include any one of the first through twentieth aspects, further comprising forming a plurality of scribe lines distributed about the circumference of the continuous glass tubing by focusing each one of a plurality of laser beams to be incident on less than respective halves of the circumference of the continuous glass tubing.

[0026] A twenty-second aspect may include the twenty-first aspect, wherein each one of the plurality of laser beams is positioned at a different angular position about a center axis A of the continuous glass tubing relative to the laser beam.

[0027] A twenty-third aspect may include any one of the first through twenty-second aspects, wherein separating the continuous glass tubing along the scribe line comprises creating a tensile stress in the continuous glass tubing at the scribe line by applying a force to the continuous glass tubing at a position downstream of the laser system.

[0028] A twenty-fourth aspect may include any one of the first through twenty-third aspects, wherein separating the continuous glass tubing along the scribe line comprises thermally shocking the continuous glass tubing at the scribe line.

[0029] A twenty-fifth aspect may include the twenty-fourth aspect, wherein thermally shocking the continuous glass tubing at the scribe line comprises cooling the continuous glass tubing at or near the scribe line.

[0030] A twenty-sixth aspect may include the twenty-fifth aspect, wherein cooling the continuous glass tubing at or near the scribe line comprises spraying the continuous glass tubing with water mist.

[0031] According to a twenty-seventh aspect of the present disclosure, a system comprises: a laser system comprising a laser source and an optical assembly, wherein the laser system is operable to produce a laser beam and configured to form a scribe line in the continuous glass tubing by focusing the laser beam to be incident on a surface of the continuous glass tubing, and wherein the laser system is configured to cause the laser beam to be incident on less than half of a circumference of the continuous glass tubing; a tube puller configured to pass thecontinuous glass tubing through the laser system; and a separating station configured to separate the continuous glass tubing along the scribe line to produce a glass tube having a fixed length.

[0032] A twenty-eighth aspect may include the twenty-seventh aspect, wherein the tube puller is configured to pass the continuous glass tubing through the laser system by moving the continuous glass tubing in a direction parallel to a center axis A of the continuous glass tubing.

[0033] A twenty-ninth aspect may include the twenty-eighth aspect, further comprising a glass tube forming apparatus positioned upstream of the laser system and the tube puller, wherein the tube puller is configured to pull the continuous glass tubing from the glass tube forming apparatus and through the laser system.

[0034] A thirtieth aspect may include any one of the twenty-seventh through twenty-ninth aspects, wherein the laser system is configured to form the scribe line over less than 180 degrees of the circumference of the continuous glass tubing.

[0035] A thirty-first aspect may include any one of the twenty-seventh through thirtieth aspects, wherein the laser system is configured to form the scribe line to have a depth that varies with angular position on the surface of the continuous glass tubing.

[0036] A thirty-second aspect may include any one of the twenty-seventh through thirty-first aspects, wherein the laser system is configured to form the scribe line to have a scribe line length Lsgreater than or equal to 0.001 times di and less than or equal to di, where di is an outer diameter of the continuous glass tubing.

[0037] A thirty-third aspect may include any one of the twenty-seventh through thirty-second aspects, wherein the laser beam comprises a wavelength from about 2 pm to about 12 pm.

[0038] A thirty-fourth aspect may include any one of the twenty-seventh through thirty-third aspects, wherein the laser beam comprises a wavelength of 1064 nm, 532 nm, 355 nm, or 266 nm.

[0039] A thirty-fifth aspect may include any one of the twenty-seventh through thirty-fourth aspects, wherein the laser system comprises a pulsed laser assembly and the laser beam is an ultrashort pulsed laser.

[0040] A thirty-sixth aspect may include any one of the twenty-seventh through thirty-fifth aspects, wherein the optical assembly comprises a collection of optical components configuredto transform the laser beam into a Bessel beam defining a laser beam focal line, and wherein the laser system is configured to focus the Bessel beam to form the scribe line as a plurality of perforations in the continuous glass tubing.

[0041] A thirty-seventh aspect may include any one of the twenty-seventh through thirtyfifth aspects, wherein the optical assembly comprises a collection of optical components configured to transform the laser beam into a Gaussian beam defining a laser beam focal point, and wherein the laser system is configured to focus the Gaussian beam to form the scribe line as an ablated trench.

[0042] A thirty-eighth aspect may include the thirty-seventh aspect, wherein the laser system is configured to form the ablated trench to have a trench width Tw greater than or equal to 20 pm and less than or equal to 50 pm.

[0043] A thirty-ninth aspect may include any one of the twenty-seventh through thirty-third, thirty-seventh, or thirty-eighth aspects, wherein the laser source is a CO2 laser.

[0044] A fortieth aspect may include any one of the thirty-seventh or thirty-ninth aspects, wherein the laser system is configured to form the ablated trench to have a trench width Tw greater than or equal to 100 pm and less than or equal to 300 pm.

[0045] A forty-first aspect may include any one of the twenty-seventh through fortieth aspects, wherein the laser source is configured to produce the laser beam to have a beam output power greater than or equal to 40 W and less than or equal to 600 W.

[0046] A forty-second aspect may include any one of the twenty-seventh through thirty-third or thirty-seventh through forty-first aspects, wherein the laser source is configured to produce the laser beam to have a wavelength greater than or equal to 9.2 pm and less than or equal to 11.2 pm.

[0047] A forty-third aspect may include any one of the twenty-seventh through forty-second aspects, further comprising a cylindrical lens positioned in a path of the laser beam and configured to convert the laser beam into a focused line, wherein the laser beam is static.

[0048] A forty-fourth aspect may include any one of the twenty-seventh through forty-second aspects, further comprising a laser beam steering device configured to scan the laser beam across the surface of the continuous glass tubing.

[0049] A forty-fifth aspect may include the forty-fourth aspect, wherein the laser beam steering device is configured to control movement of the laser beam using a mirror galvanometer or a polygon mirror.

[0050] A forty-sixth aspect may include any one of the forty-fourth or forty-fifth aspects, wherein the laser beam steering device is configured to scan the laser beam across the surface of the continuous glass tubing at an angle with respect to a center axis A of the continuous glass tubing such that the scribe line is formed perpendicular to the center axis A of the continuous glass tubing.

[0051] A forty-seventh aspect may include any one of the twenty-seventh through fortysixth aspects, wherein the separating station comprises a mechanical stressing device configured apply a force to the continuous glass tubing at a position downstream of the laser system to create a tensile stress in the continuous glass tubing at the scribe line and separate the continuous glass tubing along the scribe line.

[0052] A forty-eighth aspect may include any one of the twenty-seventh through fortyseventh aspects, wherein the separating station comprises a thermal shock device configured to thermally shock the continuous glass tubing at the scribe line to separate the continuous glass tubing along the scribe line.

[0053] A forty-ninth aspect may include the forty-eighth aspect, wherein the thermal shock device is configured to thermally shock the continuous glass tubing at the scribe line by cooling the continuous glass tubing at or near the scribe line.

[0054] A fiftieth aspect may include the forty-ninth aspect, wherein the thermal shock device is configured to cool the continuous glass tubing at or near the scribe line by spraying the continuous glass tubing with water mist.

[0055] A fifty-first aspect may include any one of the twenty-seventh through fiftieth aspects, wherein: the laser system further comprises a plurality of laser sources with corresponding optical assemblies; the laser system is further operable to produce a plurality of laser beams positioned at different angular positions about a center axis A of the continuous glass tubing relative to the laser beam; and the laser system is further configured to: form a plurality of scribe lines distributed about the circumference of the continuous glass tubing by focusing each of the plurality of laser beams to be incident on the surface of the continuous glass tubing; and cause each of the plurality of laser beams to be incident on less than respective halves of the circumference of the continuous glass tubing.

[0056] Additional features and advantages of the systems and methods disclosed herein will be set forth in the detailed description, which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein, including the detailed description, which follows, the claims, and the appended drawings.

[0057] It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various embodiments described herein, and together with the description serve to explain the principles and operations of the claimed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0058] FIG. 1 schematically depicts a side view of a system for separating continuous tubing into a plurality of lengths of glass tube, according to one or more embodiments shown and described herein;

[0059] FIG. 2 schematically depicts a side perspective view of a glass tube, according to one or more embodiments shown and described herein;

[0060] FIG. 3 schematically depicts a top view of a process for continuously producing glass tubes, according to one or more embodiments shown and described herein;

[0061] FIG. 4 schematically depicts a side elevation view of the process of FIG. 3 for continuously producing glass tubes, according to one or more embodiments shown and described herein;

[0062] FIG. 5 schematically depicts a conventional method for scoring glass tubing;

[0063] FIG. 6A schematically depicts a V-shaped groove formed by the conventional method for scoring glass tubing of FIG. 5 when the tube speed Vtube is less than the wedge speed Vwedge;

[0064] FIG. 6B schematically depicts an angled V-shaped groove formed by the conventional method for scoring glass tubing of FIG. 5 when the tube speed Vtube is greater than the wedge speed Vwedge;

[0065] FIG. 7A schematically depicts a side elevation view of the separating station of the system of FIG. 1, according to one or more embodiments shown and described herein;

[0066] FIG. 7B schematically depicts a side elevation view of the separating station of the system of FIG. 1 after a glass tube has been separated from the continuous glass tubing, according to one or more embodiments shown and described herein;

[0067] FIG. 8 schematically depicts the transformation of a laser beam into a Gaussian beam defining a laser beam focal point, according to one or more embodiments shown and described herein;

[0068] FIG. 9 schematically depicts the transformation of a laser beam into a Bessel beam defining a laser beam focal line, according to one or more embodiments shown and described herein;

[0069] FIG. 10A schematically depicts an optical assembly of a laser system of the system of FIG. 1, wherein the optical assembly is configured to transform a laser beam into a Bessel beam defining a laser beam focal line, according to one or more embodiments shown and described herein;

[0070] FIG. 10B schematically depicts a scribe line as a plurality of perforations formed by the system of FIG. 1 with the optical assembly of FIG. 10A, according to one or more embodiments shown and described herein;

[0071] FIG. 11 schematically depicts an optical assembly of a laser system of the system of FIG. 1 , wherein the optical assembly is configured to transform a laser beam into a Gaussian beam defining a laser beam focal point, according to one or more embodiments shown and described herein;

[0072] FIG. 12A schematically depicts a scribe line as an ablated trench formed by the system of FIG. 1 with the optical assembly of FIG. 11 , according to one or more embodiments shown and described herein;

[0073] FIG. 12B schematically depicts another scribe line as an ablated trench formed by the system of FIG. 1 with the optical assembly of FIG. 11, according to one or more embodiments shown and described herein;

[0074] FIG. 13 schematically depicts a laser system of the system of FIG. 1, the laser system including a CO2 laser and a mirror galvanometer, according to one or more embodiments shown and described herein;

[0075] FIG. 14 schematically depicts a laser system of the system of FIG. 1, the laser system including a CO2 laser and a polygon mirror, according to one or more embodiments shown and described herein;

[0076] FIG. 15 schematically depicts a scribe line formed on a glass tube when the line path of the laser is perpendicular to the center axis of the continuous glass tubing and the tube speed is less than the laser scan speed, according to one or more embodiments shown and described herein;

[0077] FIG. 16 schematically depicts a scribe line formed on continuous glass tubing when the line path of the laser beam is perpendicular to the center axis of the continuous glass tubing and the tube speed is greater than the scan speed;

[0078] Fig. 17 schematically depicts a scribe line formed on continuous glass tubing when the line path of the laser beam is at an angle with respect to the center axis of the continuous glass tubing and the tube speed is greater than the scan speed, according to one or more embodiments shown and described herein;

[0079] FIG. 18 schematically depicts an optical assembly of a laser system of the system of FIG. 1, wherein the optical assembly includes a cylindrical lens positioned in the path of the laser beam and configured to convert the laser beam into a focused line, according to one or more embodiments shown and described herein;

[0080] FIG. 19 schematically depicts a laser system of the system of FIG. 1, wherein the laser system comprises a plurality of lasers and is configured to form multiple scribe lines around the circumference of the continuous glass tubing, according to one or more embodiments shown and described herein;

[0081] FIG. 20 is a photograph of a section of continuous glass tubing containing a scribe line formed by an ultrashort pulsed laser passed through Bessel optics, according to one or more embodiments shown and described herein;

[0082] FIG. 21A is a photograph of an end view of a glass tube after being separated from the scribed continuous glass tubing shown in FIG. 20, according to one or more embodiments shown and described herein;

[0083] FIG. 2 IB is a photograph showing a magnified end view of the glass tube shown in FIG. 21 A;

[0084] FIG. 22 is a photograph of a section of continuous glass tubing containing a scribe line formed by an ultrashort pulsed laser passed through Gaussian optics, according to one or more embodiments shown and described herein;

[0085] FIG. 23 A is a photograph of an end view of a glass tube after being separated from the scribed continuous glass tubing shown in FIG. 22, according to one or more embodiments shown and described herein;

[0086] FIG. 23B is a photograph showing a magnified end view of the glass tube shown in FIG. 23A;

[0087] FIG. 24 is a photograph of glass tubes after being separated from continuous glass tubing, according to one or more embodiments shown and described herein;

[0088] FIG. 25 is a photograph of a section of continuous glass tubing containing a scribe line formed by a CO2 laser passed through Gaussian optics, according to one or more embodiments shown and described herein;

[0089] FIG. 26A is a photograph of an end view of a glass tube after being separated from the scribed continuous glass tubing shown in FIG. 25, according to one or more embodiments shown and described herein; and

[0090] FIG. 26B is a photograph showing a magnified end view of the glass tube shown in FIG. 26A.DETAILED DESCRIPTION

[0091] Reference will now be made in detail to embodiments of apparatuses, systems, and methods disclosed herein, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts. Referring now to FIG. 1, separating systems 100 of the present disclosure for separating continuous glass tubing 101 may include a laser system 110 comprising a laser source 112 and an optical assembly 120. The laser system 110 is operable to produce a laser beam 114 and configured to form a scribe line SL in the continuous glass tubing 101 by focusing the laser beam 114 to be incident on an outer surface 103 of the continuous glass tubing 101. The laser system 110 may be configured to cause the laser beam 114 to be incident on less than half of a circumference of the continuous glass tubing 101. The separating systems 100 may further include a tube puller 130 configured to pull the continuous glass tubing 101 through the laser system 110 and a separating station 140 configured toseparate the continuous glass tubing 101 along the scribe line SL to produce a glass tube 102 having a fixed length L.

[0092] The separating systems 100 disclosed herein can be used in methods for separating continuous glass tubing 101. The methods for separating continuous glass tubing 101 include passing the continuous glass tubing 101 through the laser system 110, forming the scribe line SL in the continuous glass tubing 101 by focusing the laser beam 114 to be incident on the outer surface 103 of the continuous glass tubing 101, and separating the continuous glass tubing 101 along the scribe line SL to produce the glass tube 102 having the fixed length L.

[0093] The systems and methods of the present disclosure may improve the repeatability, reliability, yield, and speed of the production of glass tubes. The systems and methods may be used to separate continuous glass tubing into a plurality of glass tubes at production line speeds while providing high quality ends to the separated glass tubes.

[0094] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that specific orientations be required with any apparatus. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation; and the number or type of embodiments described in the specification.

[0095] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom - are made only with reference to the figures as drawn and the coordinate axis provided therewith and are not intended to imply absolute orientation.

[0096] As used herein, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a” component includes aspects having two or more of such components, unless the context clearly indicates otherwise.

[0097] As used herein, “axial” refers to a direction parallel to the center axis A of the glass tube.

[0098] As used herein, the “beam waist” of a laser beam refers to the point along the beam path of the laser beam at which point the power density of the laser beam is greatest.

[0099] As used herein, the terms “upstream” and “downstream” refer to the positions of features of the glass tube manufacturing process relative to a direction of travel of the glass tube through the manufacturing process. For instance, a first feature is “upstream” of a second feature if the glass tube encounters the first feature before encountering the second feature. Conversely, the first feature is “downstream” of the second feature if the glass tube encounters the second feature before encountering the first feature.

[0100] As used herein, the terms “upbeam” and “downbeam” refer to the positioning of two or more features of a system relative to the direction of travel of a laser beam along a beam pathway through the system. A first component may be considered to be upbeam of a second component if the laser beam encounters the first component before encountering the second component. Conversely, a first component may be considered to be downbeam of a second component when the laser beam encounters the second component before encountering the first component.

[0101] As used herein, “laser beam focal line” refers to a pattern of interacting (e.g., crossing) light rays of a laser beam that forms a focal region elongated in the beam propagation direction. In conventional laser processing, a laser beam is tightly focused via Gaussian optics to a focal point. The focal point is the point of maximum intensity of the laser beam and is situated at a focal plane in a substrate, such as the outer surface of the continuous glass tubing. In the elongated focal region of a laser beam focal line, in contrast, the region of maximum intensity of the laser beam extends beyond a point to a line aligned with the beam propagation direction. A laser beam focal line is formed by converging light rays of a laser beam that intersect (e.g., cross) to form a continuous series of focal points aligned with the beam propagation direction.

[0102] As used herein, “squareness,” in the context of a cut edge of a separated glass tube relative to a center axis of the glass tube, refers to the degree of perpendicularity between the center axis of the glass tube and an approximated plane of separation of the cut edge.

[0103] Because of its hermeticity, optical clarity, and excellent chemical durability relative to other materials, glass has been a preferred material for pharmaceutical applications,including, without limitation, vials, syringes, ampoules, cartridges, jars, and other glass articles. These pharmaceutical glass containers, as well as other types of glass articles, can be produced through a process of converting a length of glass tube to one or more of the glass articles through a plurality of heating and forming operations. Referring to FIG. 2, one embodiment of a glass tube 102 for use as the starting point for making a plurality of glass articles is schematically depicted. The glass tube 102 comprises a hollow cylinder of glass having an outer surface 104 and an inner surface 106. The inner surface 106 defines an interior of the glass tube 102. The glass tubes 102 have a first end 107 and a second end 108 opposite the first end. The glass tubes 102 are characterized by a tube length L, an outside diameter di, and a wall thickness T. The tube length L is the distance from the first end 107 to the second end 108, and the wall thickness T refers to the average radial distance between the outer surface 104 and the inner surface 106 of the glass tube 102. The average radial distance is taken as an average around the circumference and along the tube length L of the glass tube 102. The glass tube 102 further comprises a center axis A.

[0104] The subject matter disclosed herein relates to systems, apparatuses, and methods for separating a continuous glass tube into a plurality of glass tubes during the production process for producing the glass tubes. In production of glass tubing, molten glass is first formed into a continuous hollow glass cylinder using a glass tube forming process. Processes for forming molten glass into a continuous hollow glass cylinder can include the Danner process, the Velio process, or other current or future developed processes for producing continuous hollow glass cylinders. The continuous hollow glass cylinder is then pulled through an annealing process and then separated into individual lengths of glass tubes 102, each having the tube length L. In conventional systems for producing the glass tubes 102, after separation, the ends of the glass tubes 102 are finished to both reduce the glass tubes 102 to the final length and provide finished and polished ends of the glass tubes 102.

[0105] Referring now to FIGS. 3 and 4, one embodiment of a system 200 for producing a plurality of glass tubes 102 is schematically depicted. The system 200 may include a melt furnace 210, a glass tube forming apparatus 220 downstream of the melt furnace 210, a muffle furnace 230 downstream of the glass tube forming apparatus 220, an annealing section 240 downstream of the muffle furnace 230, the separating system 100 for separating continuous glass tubing downstream of the annealing section 240, and a horizontal conveyor 111 disposed downstream of the separating system 100.

[0106] In operation of the system 200, a glass 202 is introduced to the melt furnace 210, which is operable to melt the glass to form a molten glass 212. The molten glass 212 is then passed to the glass tube forming apparatus 220, which is operable to form the molten glass 212 into the continuous glass tubing 101. As shown in FIG. 4, in embodiments, the glass tube forming apparatus 220 may be a tube forming apparatus used in the Danner process, in which the molten glass 212 runs from a feeder to a rotatable inclined hollow cylinder and is drawn off of the rotatable inclined hollow cylinder into the muffle furnace 230 by the tube puller 130 to produce the continuous glass tubing 101. While drawing the continuous glass tubing 101 off of the glass tube forming apparatus 220, compressed air or other gas supplied to the center of the continuous glass tubing 101 through the glass tube forming apparatus 220 along with the vacuum applied from the outside of the continuous glass tubing 101 may help control the tube diameter and prevent the continuous glass tubing 101 from collapsing before cooling enough to retain its shape. Although shown as a Danner process in FIG. 4, it is understood that the continuous glass tubing 101 may be made using the Velio process or any other current or future process for making continuous hollow glass cylinders.

[0107] Referring again to FIGS. 3 and 4, after being formed, the continuous glass tubing 101 is then pulled through the muffle furnace 230 and the annealing section 240 by the tube puller 130. The annealing section 240 may be operable to anneal the continuous glass tubing 101. The tube puller 130 may include one or more sets of driven rollers 132 operable to exert a pulling force on the annealed continuous glass tubing 101 sufficient to pull it through the muffle furnace 230 and the annealing section 240. After passing the annealing section 240, the annealed continuous glass tubing 101 passes to the separating system 100, where the annealed continuous glass tubing 101 is separated into glass tubes 102 having a fixed length L. This initial separation may often be referred to as a rough cut and typically involves a mechanical score and break process to produce an oversized length of glass tube.

[0108] Conventional manufacturing processes for performing the rough cut of the continuous glass tubing to produce the individual lengths of glass tubes involve using a scoring wedge or wheel to create a score line comprising a V-shaped groove or defect on the outer surface of the continuous glass tubing. In the conventional scoring method shown in FIG. 5, a scoring wedge 12 moving in a direction Mwcontacts the outer surface 13 of the continuous glass tubing 11 moving in a direction Mt to create a V-shaped groove (i.e., a scribe line SL) that may be used as a starting point to produce a fracture that propagates through and around the circumference of the continuous glass tubing 11 to separate individual lengths of glass tubefrom the continuous glass tubing 11. The fracture is propagated through the thickness and around the circumference of the continuous glass tubing 101 by applying a cantilever force on the downstream end of the continuous glass tubing 11, which in turn produces tension at the scribe line SL in the continuous glass tubing 11.

[0109] The depth, width, and angle of the V-shaped groove are highly dependent on the pressure between the wedge 12 and the continuous glass tubing 11, as well as the relative speed between the wedge 12 and the continuous glass tubing 11. As shown in FIG. 6A, if the tube speed Vtube is less than the wedge speed Vwedge, the resulting score line SL will be more perpendicular to the center axis A of the continuous glass tubing 11. However, as shown in FIG. 6B, if the tube speed Vtube is greater than the wedge speed Vwedge, the resulting score line SL will be more angled relative to the center axis A of the continuous glass tubing 11. An angled score line SL relative to the center axis A of the continuous glass tubing 11 may lead to angled ends upon separation, or worse. In some cases, such as with thin-walled glass tubing, an angled score line SL may result in severe cracking or chipping of the ends of the separated glass tubes. The length of the separated glass tube can vary significantly depending on how badly cracked the tube ends are. To compensate for this, conventional mechanical score and break methods are configured to separate the continuous glass tubing 11 into oversized lengths of the glass tube having an initial tube length that is significantly greater (e.g., at least 5% greater) than the final finished length of the glass tubes. The greater length allows for subsequent trimming and finishing of the ends.

[0110] Depending on the characteristics of the score line as well as the diameter and wall thickness of the continuous glass tubing, the separation step may vary in difficulty, and the degree of difficulty may be directly related to the resulting edge quality of the lengths of glass tubes separated from the continuous glass tubing. In some scenarios, the score line may not be deep enough for the tension created by the cantilever force to cause breakage at the score line. Since the drawing process for producing the continuous glass tubing is a continuous process, failure to separate the glass tube from the continuous glass tubing can be very problematic, because the continuous glass tubing continues traveling in the direction of draw and contacts structures in its path, resulting in crushing of the continuous glass tubing. Crushing the continuous glass tubing can result in production upsets, equipment downtime, and production losses.[oni] In an atempt to ensure separation of the oversized lengths of the glass tubes from the continuous glass tubing, some existing methods are directed to tuning the scoring equipment to increase the force applied to the outer surface of the glass tubing by the metal wedge to make a larger and deeper score line. However, this generally results in poor edge quality with extensive cracks and chipping, which requires that the tube length cut at this rough cuting step be greatly oversized to allow enough length for trimming and finishing the ends. This results in considerable glass waste and low production yield. In addition, chipping and glass particles generated during this rough cut result in undesirable debris that can end up in the final product, making the final product unable to meet quality control standards. Further, atempts to ensure separation by increasing the force applied to the outer surface of the glass tubing can lead to catastrophic crushing of the tube resulting in production upsets, equipment downtime, and production losses.

[0112] To avoid some of the above-described problems associated with mechanical score and break processes, alternative technologies have been developed for separating continuous glass tubing, some involving the use of lasers. In general, laser cuting methods offer several improvements over mechanical score and break methods, but improved cut edge quality is likely the most significant improvement. Laser cuting methods tend to generate improved cut edge quality because they are based on energy transfer between a laser and the glass tubing and do not require mechanical scoring of the glass tubing. Moreover, since laser cuting methods do not involve mechanical scoring of the glass tubing, there is no need to replace or re-sharpen tools, e.g., scoring wheels / wedges or circular saws, which is periodically performed with mechanical score and break methods. However, conventional laser cuting methods are not suitable for production line conditions, which can require processing the continuous glass tubing at a rate of 10 linear meters per second or faster. Conventional laser cuting processes cannot keep up with the fast drawing speeds (e.g., draw speeds greater than 10 linear meters per second) of modem draw processes of continuous glass tubing.

[0113] Some conventional laser cutting processes involve ablating a trench around the circumference of the glass tubing, which can take a very long time, on the order of seconds per tube, during which time the continuous glass tube can travel several meters. Others supplement the mechanical score and break method with exposure to a laser that cleaves the glass tubing by thermally stressing it at the score line. However, this laser-based cleaving process is strongly material dependent and can have a narrow process window. Moreover, this laser-based cleaving process is very difficult with thick glass tubing and typically requires the tube to berotating relative to the laser beam, which is difficult in the rough cutting stage of manufacturing processes for separating continuous glass tubing into lengths of glass tubes. Finally, additional laser-based processes for separating glass tubes from continuous glass tubing have been proposed wherein the laser beam forms a focal line that creates interconnected perforations through the wall of the glass tube, thereby providing a break location for the glass tubing when subjected to tensile stress. See United States Patent Application No. 2016 / 0009586, entitled “Systems and Methods of Glass Cutting by Inducing Pulsed Laser Perforations into Glass Articles.” However, current methods using this perforation approach require the laser to accurately rotate relative to the glass tubing, which is difficult during the rough cutting stage of manufacturing processes for separating continuous glass tubing due to the high drawing speed of the continuous glass tubing. Moreover, industry drawing speeds continue to increase, especially for thin-wall glass tubing, making existing laser-based methods for performing the rough cut less and less practical. Accordingly, there is a need for systems and methods that are able to perform the rough cut operation at production line speeds while simultaneously creating high quality cut edges of the separated glass tubes.

[0114] The present application is directed to new laser-based scribing methods for separating continuous glass tubing into individual lengths of glass tubes. The laser-based scribing methods disclosed herein may be compatible with production line speeds up to and greater than 10 linear meters per second and may be capable of providing high quality cut edges without the need to rotate the tube relative to the laser beam, or vice versa. The methods for separating continuous glass tubing of the present disclosure may include passing the continuous glass tubing through the laser system, forming the scribe line in the continuous glass tubing by focusing the laser beam to be incident on the outer surface of the continuous glass tubing, and separating the continuous glass tubing along the scribe line to produce the glass tube having the fixed length.

[0115] The methods disclosed herein may be practiced with the systems of the present disclosure for separating continuous glass tubing into the individual lengths of glass tubes. The systems disclosed herein may include a laser system comprising a laser source and an optical assembly. The laser system is operable to produce a laser beam and configured to form a scribe line in the continuous glass tubing by focusing the laser beam to be incident on the outer surface of the continuous glass tubing. The laser system may be configured to cause the laser beam to be incident on less than half of a circumference of the continuous glass tubing. The systems further include a tube puller configured to pass the continuous glass tubing through the lasersystem and a separating station configured to separate the continuous glass tubing along the scribe line to produce a glass tube having a fixed length.

[0116] The methods disclosed herein may replace conventional methods for separating continuous glass tubing into individual lengths of glass tube with a focused laser capable of creating a defect line on the outside surface of the glass tubing which, upon being subjected to tensile stress, acts as a starting point for a crack to form and propagate around the circumference of the continuous glass tubing, thereby separating the length of glass tube from the continuous glass tubing.

[0117] The new laser-based scribing and separation methods described herein may provide improved quality of the individual lengths of glass tubes with reduced chipping and cracks compared to mechanical score / break methods; improved cut edge attributes, such as squareness relative to the center axis of the glass tubing; reduced glass particle generation; and reduced waste and improved material utilization because the improved rough cut requires less excess tube length to accommodate for the removal of poorly cut ends via trimming. In particular, it is believed the systems and methods disclosed herein for separating continuous glass tubing into individual lengths of glass tubes may result in a 10-15% reduction in excess tubing needed for each glass tube produced. For example, using the conventional mechanical score and break method to produce glass tubes have a final target length of 1500 mm usually requires the designing the rough cut operation to produce an initial tube length of from about 1700 mm to about 1750 mm. The systems and methods disclosed herein may significantly reduce the excess tube length of the glass tubes at the rough cut stage, or even eliminate the need to produce the individual lengths of glass tubes with excess tube length. Moreover, the systems and methods of the present disclosure may reduce or eliminate typical steps involved in trimming and / or finishing the ends of glass tubes after the glass tubes have been separated from the continuous glass tubing.

[0118] Additionally, the laser-based separation methods described herein may offer faster separating speeds because, rather than using an object to mechanically score the outer surface of the glass tubing, the methods proposed herein are based on steering a laser beam. Unlike mechanical score and break methods that rely on heavy and / or sharp metal wheels or tips, the steering of the laser is achieved with very slight scanning mirrors or by fixed lenses. Further, the systems and methods disclosed herein do not require mechanical initiation and quenching to create a thermal shock for crack propagation. Thus, the systems and methods disclosedherein may reduce contamination of the surfaces of the glass tubes with fused glass particles, among other features. These and other benefits will be apparent in view of the present disclosure.

[0119] Referring again to FIG. 1, separating systems 100 of the present disclosure for separating continuous glass tubing 101 into individual lengths of glass tubes 102 may include a laser system 110 comprising a laser source 112 and an optical assembly 120. The laser system 110 is operable to produce a laser beam 114 and configured to form a scribe line SL in the continuous glass tubing 101 by focusing the laser beam 114 to be incident on an outer surface 103 of the continuous glass tubing 101. The laser system 110 may be configured to cause the laser beam 114 to be incident on less than half of a circumference of the continuous glass tubing 101. The separating systems 100 further include a tube puller 130 configured to pass the continuous glass tubing 101 through the laser system 110, and a separating station 140 configured to separate the continuous glass tubing 101 along the scribe line SL to produce a glass tube 102 having a fixed length L.

[0120] As discussed above, the tube puller 130 of the separating system 100 may be positioned downstream of the annealing section 240 and configured to pull the continuous glass tubing 101 from a glass tube forming apparatus 220. The tube puller 130 may be configured to pass the continuous glass tubing 101 through the laser system 110 by moving the continuous glass tubing 101 in a direction parallel to a center axis A of the continuous glass tubing 101, as shown in FIG. 1. The tube puller 130 may include one or more sets of driven rollers 132 operable to exert a pulling force on the continuous glass tubing 101 sufficient to pull it through the muffle furnace 230 and the annealing section 240. Moreover, in embodiments, the separating station 140 may include one or more sets of support rollers 142 for supporting the continuous glass tubing 101 downstream from the laser station 110. The support rollers 142 may function as a fulcrum to aid separation of the glass tube 102 from the continuous glass tubing 101.

[0121] Referring now to FIGS. 7A and 7B, an embodiment of the separating station 140 is described in more detail. FIG. 7A shows the separating station 140 prior to separating the glass tube 102 from the continuous glass tubing 101. FIG. 7B shows the separating station 140 after the continuous glass tubing 101 has fractured at the scribe line SL, thereby producing the glass tube 102. As discussed above, the separating station 140 may be positioned downstream fromthe laser system 110. The separating station 140 may comprise driven rollers 142 configured to pull the continuous glass tubing 101 through the separating system 100.

[0122] In embodiments, the separating station 140 may comprise a mechanical stressing device 144 configured to apply a force to the continuous glass tubing 101 at a position downstream of the laser system 110 to create a tensile stress in the continuous glass tubing 101 at the scribe line SL and separate the continuous glass tubing 101 along the scribe line SL. In embodiments, the mechanical stressing device 144 may be a rotating bar that applies the force to the continuous glass tubing 101 at a position downstream of the laser system 110 to create a tensile stress in the continuous glass tubing 101 at the scribe line SL.

[0123] In embodiments, the separating station 140 may comprise a thermal shock device 146 configured to thermally shock the continuous glass tubing 101 at the scribe line SL to separate the continuous glass tubing 101 along the scribe line SL. The thermal shock device 146 may be configured to thermally shock the continuous glass tubing 101 at the scribe line SL by cooling, in particular, by quenching, the continuous glass tubing 101 at or near the scribe line SL . The thermal shock device 146 may be able to take advantage of a high tube temperature incident to a tube forming process, such as the Danner or Velio processes discussed above. By cooling the continuous glass tubing 101 at or near the scribe line SL, the induced temperature differential of the continuous glass tubing 101 may cause the cooled region to thermally contract more quickly than the surrounding region. This differential contraction may create a tensile stress in the continuous glass tubing 101 at the scribe line SL helpful for initiating a crack at the scribe line SL and propagating the crack around the circumference of the continuous glass tubing 101, thereby separating the continuous glass tubing 101 along the scribe line SL.

[0124] In the embodiment shown in FIGS. 7A and 7B, the thermal shock device 146 may be configured to cool the continuous glass tubing 101 at or near the scribe line SL by spraying the continuous glass tubing 101 with a cooling fluid 147, such as but not limited to a water mist. However, other cooling fluids 147 could be used by the thermal shock device 146 to cool the continuous glass tubing 101 rapidly enough to thermally shock the continuous glass tubing 101 thereby initiating fracture at the scribe line SL. The temperature differential implemented to initiate fracture at the scribe line SL may depend on characteristics of the continuous glass tubing 101, such as, for example, the outer diameter di of the continuous glass tubing 101, the wall thickness T of the continuous glass tubing 101, and the mechanical properties of the glassmaterial forming the continuous glass tubing 101. For example, thicker tubing may require a larger temperature differential to initiate and drive a crack around the circumference of the continuous glass tubing 101. In embodiments, the thermal shock device 146 may be configured to cause a temperature differential of greater than or equal to 150°C, greater than or equal to 170°C, greater than or equal to 190°C, greater than or equal to 210°C, or greater than or equal to 230°C. In embodiments, the temperature of the continuous glass tubing 101 as it approaches the thermal shock device 146 may be approximately 220°C and the temperature of the cooling fluid 147 may be approximately 30°C, thereby inducing a temperature differential at the scribe line SL of 190°C.

[0125] In the embodiment shown in FIGS. 7A and 7B, the separating station 140 may comprise both the mechanical stressing device 144 and the thermal shock device 146; however, it should be understood that either of the mechanical stressing device 144 or the thermal shock device 146 could be used individually without the other. Further, in embodiments, sufficient tensile stress at the scribe line SL may be induced via a cantilever effect resulting from the weight of the length of glass tubing downstream of the scribe line SL, such that neither the mechanical stressing device 144 nor the thermal shock device 146 is necessary to separate the glass tube 102 from the continuous glass tubing 101.

[0126] As discussed above and shown in FIG. 1, the laser system 110 may be positioned downstream from the tube puller 130. In embodiments, the laser system 110 may be positioned upstream from the mechanical stress device 144, the thermal shock device 146, or both, when present. The laser system 110 may comprise the laser source 112 and the optical assembly 120. In embodiments, the laser system 110 may be configured to form the scribe line SL over less than 180 degrees of the circumference of the continuous glass tubing 101. In embodiments, the laser system 110 may be configured to form the scribe line SL to have a depth that varies with angular position on the outer surface 103 of the continuous glass tubing 101.

[0127] In embodiments, the laser system 110 may be configured to form the scribe line SL to have a scribe line length Lsgreater than or equal to 0.001 times di, greater than or equal to 0.005 times di, greater than or equal to 0.01 times di, greater than or equal to 0.05 times di, greater than or equal to 0.1 times di, greater than or equal to 0.3 times di, greater than or equal to 0.5 times di, greater than or equal to 0.6 times di, greater than or equal to 0.7 times di, greater than or equal to 0.8 times di, or greater than or equal to 0.9 times di, where di is the outer diameter of the continuous glass tubing 101. In embodiments, the laser system 110 maybe configured to form the scribe line SL such that the scribe line length Lsis less than or equal to di. With reference to FIG. 10B, in embodiments wherein the scribe line SL is formed as a plurality of perforations 121 in the continuous glass tubing 101, the scribe line length Lsmay be defined as the distance between the outermost perforations 121 of the plurality of perforations 121 forming the scribe line SL. With reference to FIGS. 12A and 12B, in embodiments wherein the scribe line SL is formed as an ablated trench 123, the scribe line length Ls, i.e. the trench length Lt, may be defined as the largest linear dimension of the ablated trench 123 in a direction parallel to a tangent of the circumference of the continuous glass tubing 101.

[0128] In embodiments, the laser system 110 may be configured to form the scribe line SL such that the scribe line length Lsis greater than or equal to 0.001 times di and less than or equal to di, greater than or equal to 0.001 times di and less than or equal to 0.9 times di, greater than or equal to 0.001 times di and less than or equal to 0.8 times di, greater than or equal to 0.001 times di and less than or equal to 0.7 times di, greater than or equal to 0.001 times di and less than or equal to 0.6 times di, greater than or equal to 0.001 times di and less than or equal to 0.5 times di, greater than or equal to 0.001 times di and less than or equal to 0.4 times di, greater than or equal to 0.001 times di and less than or equal to 0.3 times di, greater than or equal to 0.001 times di and less than or equal to 0.2 times di, or greater than or equal to 0.001 times di and less than or equal to 0. 1 times di.

[0129] In embodiments, the laser system 110 may be configured to form the scribe line SL such that the scribe line length Lsis greater than or equal to 0.01 times di and less than or equal to di, greater than or equal to 0.01 times di and less than or equal to 0.7 times di, greater than or equal to 0.05 times di and less than or equal to 0.7 times di, greater than or equal to 0.1 times di and less than or equal to 0.7 times di, greater than or equal to 0.3 times di and less than or equal to 0.7 times di, greater than or equal to 0.3 times di and less than or equal to 0.5 times di, or greater than or equal to 0.5 times di and less than or equal to 0.7 times di.

[0130] The scribe line length Lsmay be related to the amount of tensile stress required to initiate fracture at the scribe line SL to separate the glass tube 102 from the continuous glass tubing 101. Many factors may influence the level of tensile stress that may be implemented at the scribe line SL. For example, the outer diameter di of the continuous glass tubing 101, the wall thickness T of the continuous glass tubing 101, the fixed length L of the glass tube 102 to be separated from the continuous glass tubing 101, the speed at which the continuous glasstubing 101 is passed through the separating system 100, or combinations of these may influence the level of tensile stress that may be implemented at the scribe line SL to separate the glass tube 102 from the continuous glass tubing 101. As such, in embodiments, to the extent these or other factors limit the amount of tensile stress that may be applied at the scribe line SL, the scribe line length Lsmay be adjusted in view of such factors to promote separation of the glass tube 102 from the continuous glass tubing 101.

[0131] In embodiments, the scribe line length Lsmay be approximately equal to the outer diameter di of the continuous glass tubing 101. By setting the scribe line length Lsto be approximately equal to the outer diameter di of the continuous glass tubing 101 , the amount of stress required to separate the glass tube 102 from the continuous glass tubing 101 may be reduced, and as a result, the cosmetic quality of the ends of the glass tube 102, e.g., the extent of chipping, cracking, etc., may be improved. However, as discussed above, the scribe line length Lsmay alternatively be a fraction of the outer diameter di of the continuous glass tubing 101. In such embodiments, the speed at which the continuous glass tubing 101 is passed through the separating system 100 may be increased while maintaining an acceptable cosmetic quality of the ends of the glass tube 102.

[0132] In embodiments, the outer diameter di of the continuous glass tubing 101 may be from 4.0 mm to 325 mm, from 4.0 mm to 300 mm, from 4.0 mm to 250 mm, from 4.0 mm to 200 mm, from 4.0 mm to 150 mm, from 4.0 mm to 100 mm, from 4.0 mm to 90 mm, from 4.0 mm to 80 mm, from 4.0 mm to 70 mm, from 5.0 mm to 60 mm, from 5.0 mm to 50 mm, from 6.0 mm to 50 mm, from 10 mm to 50 mm, from 10 mm to 40 mm, from 15 mm to 40 mm, or from 20 mm to 40 mm. In embodiments, the outer diameter di of the continuous glass tubing 101 may be about 8.15 mm, about 16 mm, about 24 mm, about 30 mm, or about 47 mm. In embodiments, the outer diameter di of the continuous glass tubing 101 may correspond to standardized outer diameters for glass pharmaceutical vials, such as those provided in ISO 8362-1:2018 or in standards created by the Glass Packaging Institute (GPI). In embodiments, the outer diameter di of the continuous glass tubing 101 may correspond to standardized outer diameters for glass ampoules, such as those provided in ISO 9187-1:2010. In embodiments, the outer diameter di of the continuous glass tubing 101 may correspond to standardized outer diameters for glass syringes, such as those provided in ISO 11040-4. In embodiments, the outer diameter di of the continuous glass tubing 101 may correspond to standardized outer diameters for glass cartridges, such as those provided in ISO 21881:2019.

[0133] The laser source 112 may be operable to produce the laser beam 114. In embodiments, the laser beam 114 may have a wavelength in a wavelength range within which the laser beam 114 is absorbed by the glass of the continuous glass tubing 101, via linear or nonlinear interaction, to heat the glass and does not pass through the glass to a significant extent. Because silicate-based glasses have strong absorption of light having wavelengths greater than or equal to about 4 micrometers (pm), in embodiments where the laser beam 114 is designed to be absorbed at the glass surface, e.g., to form an ablated trench in the outer surface 103 of the continuous glass tubing 101, many different laser sources can be used to produce the laser beam 114. In embodiments, the laser source 112 may be a CO laser (about 4 pm to about 6 pm, typically 5.3 pm), a CO2 laser (about 9.2 pm to about 11.2 pm, typically 10.6 pm), a quantum cascade laser (QCL), an Er:YAG laser (about 3 pm to about 4 pm), an Excimer laser (UV wavelength), or other type of suitable laser source capable of producing the laser beam 114 having a wavelength in one of the ranges described herein.

[0134] The laser source 112 may be operable to produce the laser beam 114 having a wavelength in the infrared wavelength region, such as the far infrared region. The laser source 112 may be operable to produce the laser beam 114 having a wavelength of greater than or equal to about 1 pm, greater than or equal to about 2 pm, greater than or equal to about 3 pm, greater than or equal to about 4 pm, or even greater than or equal to about 8 pm. The laser source 112 may be operable to produce the laser beam 114 having a wavelength of less than or equal to about 12 pm, or even less than or equal to about 11 pm. The laser source 112 may be operable to produce the laser beam 114 having a wavelength of from about 1 pm to about 12 pm, from about 1 pm to about 11 pm, from about 2 pm to about 12 pm, from about 2 pm to about 11 pm, from about 3 pm to about 12 pm, from about 3 pm to about 11 pm, from about 4 pm to about 12 pm, from about 4 pm to about 11 pm, from about 5 pm to about 12 pm, from about 5 pm to about 11 pm, from about 8 pm to about 12 pm, or from about 8 pm to about 11 pm. The specific wavelength range may depend in part on the type of glass composition comprising the glass tubes.

[0135] In embodiments, the wavelength of the laser beam 114 may be selected so that the glass of the continuous glass tubing is transparent to the wavelength of the laser beam 114. Borosilicate or soda-lime glasses without other colorations (in particular with low iron content) are optically transparent from about 350 nm to about 2.5 pm. For example, the wavelength of the laser beam 114 may be less than about 1.8 pm, or between about 900 nm to about 1200 nm. In embodiments, the laser source 112 is operable to produce the laser beam 114 having awavelength of about 1064 nm, about 532 nm, about 355 nm, or about 266 nm. Non-limiting suitable examples of laser sources include Nd:YAG lasers with a wavelength of about 1064 nm and Y :YAG lasers with a wavelength of about 1030 nm.

[0136] The laser source 112 may be operable to produce the laser beam 114 as a continuous or pulsed laser. Continuous lasers generally have lower peak power and raise the glass surface temperature gradually, while pulsed lasers generally have high peak power and raise glass temperature to a greater degree in the shorter period of time compared to continuous lasers. In embodiments in which the laser beam 114 comprises a pulsed laser beam, the pulse duration of the individual pulses is in a range of from about 1 femtosecond to about 200 picoseconds, such as from about 1 picosecond to about 100 picoseconds, 5 picoseconds to about 20 picoseconds, or the like, and the repetition rate of the individual pulses may be in a range from about 1 kHz to 4 MHz, such as in a range from about 10 kHz to about 3 MHz, or from about 10 kHz to about 650 kHz. In embodiments, the laser beam 114 may form the scribe line SL with a single pulse. In embodiments, the laser system 110 may be a pulsed laser assembly and the laser source 112 may be operable to produce the laser beam 114 as an ultrashort (i.e., from 10'10to 10'15second) pulsed laser.

[0137] In embodiments, pulsed lasers may be well suited for scoring the continuous glass tubing 101 due to the greater peak intensity of the pulsed lasers . The intensity of the laser beam 114 may be chosen on the basis of the pulse duration and the pulse energy. In embodiments discussed in more detail herein, wherein the laser beam 14 is transformed into a quasi-non-diffracting beam defining a laser beam focal line, the focal line diameter may be controlled such that there is no significant ablation or significant melting of the glass, but only the formation of defects, referred to herein as “perforations,” in the microstructure of the glass. The pulse energy of the laser may be selected such that the intensity in the laser beam focal line produces an induced absorption, which may in turn lead to the creation of a highly controlled full line perforation in the area of the glass where the laser beam focal line is present.

[0138] As used herein, the term “quasi-non-diffracting beam” is used to describe a laser beam having low beam divergence as described below. The quasi-non-diffracting laser beam can be formed by impinging a diffracting laser beam (such as a Gaussian beam) into, onto, and / or through a phase-altering optical element, such as an adaptive phase-altering optical element (e.g., a spatial light modulator, an adaptive phase plate, a deformable mirror, or the like) and / or a static phase-altering optical element (e.g., a static phase plate, an aspheric opticalelement, such as an axicon, or the like), to modify the phase of the beam, to reduce beam divergence, and to increase Rayleigh range, as defined in United States Patent Application Publication No. 2023 / 0116816, entitled “Apparatus and Method for Edge-Strength Enhanced Glass.”

[0139] In embodiments wherein a pulsed laser beam is used, the laser beam 114 may have an average pulse laser energy measured at the outer surface 103 of the continuous glass tubing 101 of greater than or equal to about 1 pJ and less than or equal to about 2000 pj, greater than or equal to about 1 pJ and less than or equal to about 1500 pj, greater than or equal to about 1 pj and less than or equal to about 1000 pj, greater than or equal to about 1 pJ and less than or equal to about 700 pj, greater than or equal to about 1 pJ and less than or equal to about 500 pj, or greater than or equal to about 1 pJ and less than or equal to about 250 pj. In embodiments, the laser beam 114 may have an average pulse laser energy measured at the outer surface 103 of the continuous glass tubing 101 of greater than or equal to about 100 pj and less than or equal to about 700 pj, greater than or equal to about 100 pj and less than or equal to about 500 pj, or greater than or equal to about 100 pj and less than or equal to about 250 pj.

[0140] The beam output power of the laser beam 114 may be adjusted in accordance with the desired scribe rate, which may depend on the speed at which the continuous glass tubing 101 is driven by the tube puller 130. In embodiments, the beam output power of the laser beam 114 may be greater than or equal to 10 W (watts) and less than or equal to 2000 W, greater than or equal to 40 W (watts) and less than or equal to 2000 W, greater than or equal to 40 W and less than or equal to 1500 W, greater than or equal to 40 W and less than or equal to 1000 W, greater than or equal to 40 W and less than or equal to 600 W, or greater than or equal to 40 W and less than or equal to 400 W. In embodiments, the beam output power of the laser beam 114 may be greater than 2000 W. In embodiments, the beam output power of the laser beam 114 may be less than or equal to 50 W.

[0141] The optical assembly 120 may be positioned downbeam from the laser source 112 and may comprise a collection of one or more optical components (e.g., lenses, mirrors, filters, etc.) that modify one or more characteristics (e.g., shape, power density, power density distribution, etc.) of the laser beam 114 prior to the incidence of the laser beam 114 on the outer surface 103 of the continuous glass tubing 101.

[0142] In embodiments, the optical assembly 120 may comprise a collection of one or more optical components configured to transform the laser beam 114 into a Gaussian beam defininga laser beam focal point 116, as shown in FIG. 8. The laser beam focal point 116 may correspond to the beam waist of the Gaussian beam. In such embodiments, a spherical lens 122 may be used to transform the laser beam 114 into the Gaussian beam defining the laser beam focal point 116, and the laser system 110 may be configured to focus the Gaussian beam to form the scribe line SL as an ablated trench in the outer surface 103 of the continuous glass tubing 101. The optical assembly 120 may comprise other optic components capable of transforming the laser beam 114 into the Gaussian beam, such as but not limited to those described in United States Patent Application Publication No. 2021 / 0387288, entitled “Method for Laser Processing Coated Substrates Using a Top-Hat Energy Distribution,” the entire contents of which are incorporated herein by reference.

[0143] In embodiments, the optical assembly 120 may comprise a collection of one or more optical components configured to transform the laser beam 114 into a quasi -non-diffracting beam defining a laser beam focal line. Exemplary quasi-non -diffracting beams include Bessel beams, Gauss-Bessel beams, Airy beams, Weber beams, and Mathieu beams, all of which have field profiles typically given by special functions that decay more slowly in the transverse direction (i.e. direction of beam propagation) compared to the Gaussian function.

[0144] In embodiments, the laser system 110 may be configured to focus the laser beam focal line 118 to form the scribe line SL as a plurality of perforations 121 (shown in FIG. 10B) in the continuous glass tubing 101. In embodiments, the optical assembly 120 may comprise a collection of one or more optical components configured to transform the laser beam 114 into a Bessel beam defining the laser beam focal line 118, as shown in FIG. 9. In such embodiments, an axicon 124 may be used to transform the laser beam into the Bessel beam defining the laser beam focal line 118, and the laser system 110 may be configured to focus the Bessel beam towards the continuous glass tubing 101 to form the scribe line SL as the plurality of perforations 121 in the continuous glass tubing 101.

[0145] The optical assembly 120 may comprise other optical components capable of transforming the laser beam 114 into a quasi-non-diffracting beam defining the laser beam focal line, such as but not limited to those described in United States Patent Application Publication No. 2015 / 0165563, entitled “Stacked Transparent Material Cutting with Ultrafast Laser Beam Optics, Disruptive Layers and Other Layers,” United States Patent Application Publication No. 2016 / 0009586, entitled “Systems and Methods of Glass Cutting by Inducing Pulsed Laser Perforations into Glass Articles,” United States Patent Application PublicationNo. 2021 / 0387288, entitled “Method for Laser Processing Coated Substrates Using a Top-Hat Energy Distribution,” United States Patent Application Publication No. 2022 / 0073401, entitled “Methods and Optical Assemblies for High Angle Easer Processing of Transparent Workpieces,” and United States Patent No. 10,047,001, entitled “Glass Cutting Systems and Methods Using Non-Diffracting Laser Beams,” all of which are incorporated herein by reference in their entirety.

[0146] It is also contemplated that the laser beam focal line may be formed using nonlinear fdamentation via the Kerr effect, which produces a self-focusing phenomenon. Additional information via nonlinear fdamentation can be found in United States Patent Application Publication No. 2021 / 0265393, entitled “Glass Cutting Systems And Methods Using Non-Diffracting Laser Beams,” the entire contents of which are incorporated herein by reference.

[0147] Referring now to FIGS. 10A and 10B, embodiments of the optical assembly 120 of the laser system 110 may comprise a collection of one or more optical components configured to transform the laser beam 114 into a Bessel beam defining a laser beam focal line 118, wherein the laser system 110 is configured to focus the Bessel beam through the thickness of the continuous glass tubing 101 to form the scribe line SL as a plurality of perforations 121 in the continuous glass tubing 101. The optical assembly 120 may transform the laser beam 114 into the Bessel beam using optical components, such as but not limited to the axicon 124 depicted in FIG. 10A. While the optical assembly 120 in FIG. 10A is shown as including the axicon 124, it should be understood that other optical components, e.g., mirrors, fdters, lenses, etc., may also be utilized in the optical assembly 120 to transform the laser beam 114 into the Bessel beam. For example, in addition to axicons, various other quasi-non-diffracting beam forming optical elements are contemplated, for example, a spatial light modulator, an elliptical lens, or combinations thereof. Bessel beams may be readily produced by axicons; however, other quasi-non-diffracting beams may be produced with other quasi-non-diffracting beam forming optical elements.

[0148] The plurality of perforations 121 forming the scribe line SL are depicted for illustration in FIG. 10B (not drawn to scale). The spacing between the perforations 121 may be uniform or nonuniform. In embodiments, the perforations 121 are holes having a cross- sectional diameter of from about 200 nm to about 800 nm, or from about 300 nm to about 500 nm. In embodiments, the plurality of perforations 121 forming the scribe line SL may be spacedapart from one another by a distance of from about 1 pm to about 30 pm, from about 1 pm to about 5 pm, or from about 1 pm to about 3 pm. The perforation spacing may be precisely induced by controlling the relative motion of the laser beam 114 and the continuous glass tubing 101.

[0149] The optical components of the optical assembly 120 may be configured such that the laser beam 114 is able to translate relative to the continuous glass tubing 101, as shown by the double-sided arrow 125 in FIG. 10A. In embodiments, the optical assembly 120 may comprise an actuator (not shown) configured to translate the laser beam 114 relative to the continuous glass tubing 101. In this manner, contrary to previously explored methods, the laser beam 114, though possible in embodiments, is not required to rotate relative to the center axis A of the continuous glass tubing 101 (center axis A shown in FIG. 1). The present inventors have found that a laser-based scribe line need not be created around the entire circumference of the continuous glass tubing to adequately promote separation at the scribe line, as is believed to be the case with prior laser-based scribing methods for glass tubing. Creating the scribe line around the entire circumference of the continuous glass tubing is time intensive and limits the rate in which glass tubes can be separated from the continuous glass tubing. The methods for separating a continuous glass tube into a plurality of glass tubes of the present disclosure avoid these limitations by forming the scribe line over just a portion of the circumference of the continuous glass tubing.

[0150] In embodiments, the laser system 110 may be configured to translate the laser beam 114 relative to the continuous glass tubing 101, e.g., in a direction parallel to a tangent of the circumference of the continuous glass tubing 101, such that the scribe line SL is formed through the thickness of the continuous glass tubing 101 along the same direction. As discussed in more detail herein, the laser system 110 may also be configured to translate the laser beam 114 toward and away from the outer surface 103 ofthe continuous glass tubing 101, i.e., in the + / - Z direction of the coordinate axis in FIG. 10A. In embodiments, the laser system 110 may be configured to translate the laser beam 114 in a direction parallel to the center axis A of the continuous glass tubing 101, i.e., in the + / - Y direction ofthe coordinate axis in FIG. 10A.

[0151] FIG. 10B schematically depicts a partial cross section ofthe continuous glass tubing 101 containing the scribe line SL. As shown, the scribe line SL may have a scribe line length Lsand a scribe line depth Ds. The scribe line length Lsmay be defined as the distance between the outermost perforations 121 ofthe plurality of perforations 121 forming the scribe line SL.In embodiments in which the perforations 121 of the plurality of perforations 121 are not parallel, e.g., in embodiments wherein the laser beam 114 is rotated relative to the center axis A of the continuous glass tubing 101, the scribe line length Lsmay be defined as the distance between the outermost points of the outermost perforations 121 of the plurality of perforations 121 forming the scribe line SL, e.g., in the + / - X direction of the coordinate axis in FIG. 10B. The scribe line depth Dsmay be defined as the distance in which the perforations extend into the glass of the continuous glass tubing.

[0152] The laser beam focal line 118 may have a defined focal line length Lf and an intensity sufficient to materially alter the continuous glass tubing 101 through the thickness to form the plurality of perforations 121. Each perforation 121 may comprise a region of the glass wherein the structure of the glass is disrupted so as to constitute a site of mechanical weakness. Structural disruptions may include compaction, melting, dislodging of material, rearrangements, and bond scission. The perforations 121 may have a cross-sectional shape consistent with the cross-sectional shape of the laser beam 114 (generally circular). The average diameter of the perforations 121 may be in the range from 0.1 pm to 50 pm, or in the range from 1 pm to 20 pm, or in the range from 2 pm to 10 pm, or in the range from 0.1 pm to 5 pm. In some embodiments, each perforation 121 may be a “through hole,” which is a hole or an open channel that extends through the thickness of the continuous glass tubing 101. In some embodiments, the perforations 121 may not be continuously open channels and may include sections of solid material dislodged from the glass by the laser beam 114. The dislodged material may block or partially block the space defined by the perforation. One or more open channels (unblocked regions) may be dispersed between sections of dislodged material. The diameter of the open channels may be less than or equal to 1000 nm, or less than or equal to 500 nm, less than or equal to 400 nm, less than or equal to 300 nm, in the range from 10 nm to 750 nm, or in the range from 100 nm to 500 nm. The disrupted or modified area (e.g, compacted, melted, or otherwise changed) of the material surrounding the holes in the embodiments disclosed herein, may have a diameter of less than or equal to 50 pm (e.g, less than or equal to 10 pm).

[0153] The individual perforations 121 can be created at rates of several hundred kilohertz (several hundred thousand perforations per second, for example). Thus, with relative motion between the laser beam 114 and the continuous glass tubing, these perforations can be placed adjacent to one another (spatial separation varying from sub-micron to several or even tens ofmicrons as desired). This spatial separation may selected in order to facilitate separation of the glass tubes 102 from the continuous glass tubing 101.

[0154] In embodiments, the focal line length Lf may be between about 0.1 mm and about 4 mm. The scribe line depth Dsmay correspond to the region of overlap between the focal line length Lf of the laser beam focal line 118 and the continuous glass tubing 101. In embodiments, the perforations 121 forming the scribe line SL do not extend through the entire wall thickness T of the continuous glass tubing 101, i.e., the scribe line depth Dsmay be less than the wall thickness T of the continuous glass tubing 101. In embodiments, the perforations 121 forming the scribe line SL may extend to different depths in the continuous glass tubing 101. When the perforations 121 extend to different depths into the continuous glass tubing 101, the scribe line depth Dsmay be defined as the depth of the largest perforation 121 (e.g., the perforation penetrating to the greatest depth in the continuous glass tubing 101).

[0155] The plurality of perforations 121 forming the scribe line SL provides a controlled region of mechanical weakness within the continuous glass tubing 101 that allows the continuous glass tubing 101 to be precisely fractured or separated (mechanically or thermally) along the path defined by the series of laser-induced defects. In other words, the plurality of perforations defines a path of least resistance for fracture propagation through the thickness of the continuous glass tubing 101 and around the circumference of the continuous glass tubing 101.

[0156] Referring now to FIG. 11, embodiments of the optical assembly 120 of the laser system 110 may comprise a collection of one or more optical components configured to transform the laser beam 114 into a Gaussian beam defining a laser beam focal point 116. The laser system 110 may be configured to focus the Gaussian beam to form the scribe line SL as an ablated trench 123 in the outer surface 103 of the continuous glass tubing 101. The optical assembly 120 may transform the laser beam 114 into the Gaussian beam using any of the optical components discussed herein. In embodiments, the optical assembly 120 may comprise a laser beam steering device 126 configured to scan the laser beam 114 across the outer surface 103 of the continuous glass tubing 101. In the embodiment shown in FIG. 11, the laser beam steering device 126 is a scanning mirror that directs the laser beam 114 through a spherical lens 122 and towards the continuous glass tubing 101. In embodiments, the laser beam steering device 126 may be a mirror galvanometer 126A or a polygon mirror 126B (e.g., see FIGS. 13 and 14). While the optical assembly 120 in FIG. 11 is shown as only including the laser beamsteering device 126 and the spherical lens 122, it should be understood that other optical components, e.g., mirrors, filters, lenses, etc., may also be included in the optical assembly 120. The spherical lens 122 may transform the laser beam 114 into the Gaussian beam defining the laser beam focal point 116. The optical assembly 120 may position the laser beam focal point 116 on the outer surface 103 of the continuous glass tubing 101, and the laser beam steering device 126 of the optical assembly 120 may be operable to scan the laser beam focal point 116 along the outer surface 103 of the continuous glass tubing 101, as shown in FIG. 11, to form the scribe line SL comprising the ablated trench 123.

[0157] The ablated trench 123 may comprise a trench length Lt, a trench width Wt, and a trench depth Dt. The trench length Lt may be defined as the largest linear dimension of the ablated trench 123 in a direction parallel to a tangent of the circumference of the continuous glass tubing 101, e.g., in the + / - X direction of the coordinate axis in FIG. 11. The trench depth Dt may be defined as the peak depth in which the ablated trench 123 extends into the continuous glass tubing 101 from the outer surface 103 of the continuous glass tubing 101. The trench width Wt may be defined as the distance between the edges of the ablated trench 123 in a direction perpendicular to the trench length Lt., e.g., in the + / - Y direction of the coordinate axis in FIG. 11. The trench length Lt, trench depth Dt, and trench width Wt correspond to the scribe line length Ls, scribe line depth Ds, and scribe line width Ws, respectively, with respect to the scribe line SL formed as the ablated trench 123.

[0158] As shown in FIGS. 12A and 12B, the dimensions of the ablated trench 123 may be adjusted depending on the production demands and the difficulty of separation based on tube diameter, wall thickness, and / or glass composition. For example, thicker walled tubing may require longer, deeper, or wider (or a combination of these) ablated trenches 123 to adequately promote separation of the glass tube 102 from the continuous glass tubing 101. The trench width Wt and depth Dt may be controlled by adjusting the wavelength, beam output power, and scan speed of the laser beam 114. In embodiments, the trench width Wt may be greater than or equal to 20 pm and less than or equal to 1000 pm, greater than or equal to 20 pm and less than or equal to 500 pm, greater than or equal to 20 pm and less than or equal to 300 pm, greater than or equal to 20 pm and less than or equal to 100 pm, greater than or equal to 30 pm and less than or equal to 500 pm, greater than or equal to 40 pm and less than or equal to 500 pm, greater than or equal to 50 pm and less than or equal to 500 pm, greater than or equal to 50 pm and less than or equal to 300 pm, greater than or equal to 100 pm and less than or equal to 300 pm, greater than or equal to 20 pm and less than or equal to 100 pm, greater than orequal to 20 pm and less than or equal to 80 pm, or greater than or equal to 20 pm and less than or equal to 50 pm.

[0159] In embodiments, the parameters of the laser beam 114 may be set such that the ablated trench 123 extends through the entire wall thickness T of the continuous glass tubing 101, which may make it easier to separate the glass tube 102 from the continuous glass tubing 101. In embodiments, the ablated trench 123 may extend through just a portion of the wall thickness T of the continuous glass tubing 101. The trench depth Dt may be from 10% to 100% of the wall thickness T of the continuous glass tubing 101, from 20% to 100% of the wall thickness T of the continuous glass tubing 101, from 30% to 100% of the wall thickness T of the continuous glass tubing 101, from 40% to 100% of the wall thickness T of the continuous glass tubing 101, from 50% to 100% of the wall thickness T of the continuous glass tubing 101, from 60% to 100% of the wall thickness T of the continuous glass tubing 101, from 70% to 100% of the wall thickness T of the continuous glass tubing 101, from 80% to 100% of the wall thickness T of the continuous glass tubing 101, from 90% to 100% of the wall thickness T of the continuous glass tubing 101, from 25% to 75% of the wall thickness T of the continuous glass tubing 101, or from 50% to 75% of the wall thickness T of the continuous glass tubing 101. As discussed above with respect to the scribe line length Ls, the trench depth Dt may be adjusted to control the amount of stress needed to initiate fracture at the scribe line SL to separate the glass tube 102 from the continuous glass tubing 101, while taking into account other factors such as the speed at which the continuous glass tubing 101 is passed through the separating system 100 and the cosmetic quality of the ends of the separated glass tube 102.

[0160] The trench length Lt may also be controlled by adjusting the settings of the laser beam steering device 126. In embodiments, the trench length Lt may be greater than or equal to 0.001 times di, greater than or equal to 0.005 times di, greater than or equal to 0.01 times di, greater than or equal to 0.05 times di, greater than or equal to 0.1 times di, greater than or equal to 0.3 times di, greater than or equal to 0.5 times di, greater than or equal to 0.6 times di, greater than or equal to 0.7 times di, greater than or equal to 0.8 times di, or greater than or equal to 0.9 times di, where di is the outer diameter of the continuous glass tubing 101. In embodiments, the trench length Lt may be less than or equal to di.

[0161] In embodiments, the trench length Lt may be greater than or equal to 0.001 times di and less than or equal to di, greater than or equal to 0.001 times di and less than or equal to0.9 times di, greater than or equal to 0.001 times di and less than or equal to 0.8 times di, greater than or equal to 0.001 times di and less than or equal to 0.7 times di, greater than or equal to 0.001 times di and less than or equal to 0.6 times di, greater than or equal to 0.001 times di and less than or equal to 0.5 times di, greater than or equal to 0.001 times di and less than or equal to 0.4 times di, greater than or equal to 0.001 times di and less than or equal to 0.3 times di, greater than or equal to 0.001 times di and less than or equal to 0.2 times di, or greater than or equal to 0.001 times di and less than or equal to 0.1 times di.

[0162] In embodiments, the trench length Lt may be greater than or equal to 0.01 times di and less than or equal to di, greater than or equal to 0.01 times di and less than or equal to 0.7 times di, greater than or equal to 0.05 times di and less than or equal to 0.7 times di, greater than or equal to 0. 1 times di and less than or equal to 0.7 times di, greater than or equal to 0.3 times di and less than or equal to 0.7 times di, greater than or equal to 0.3 times di and less than or equal to 0.5 times di, or greater than or equal to 0.5 times di and less than or equal to 0.7 times di.

[0163] Referring now to FIGS. 13 and 14, in embodiments, the laser system 110 may comprise a CO2 laser as the laser source 112, in combination with a laser beam steering device 126 configured to move the laser beam 114 with a pre-set scan speed on a pre-set line path (straight or angled with respect to the center axis A of the continuous glass tubing 101 ) to create the scribe line SL as an ablated trench 123. While not shown in FIGS. 13 and 14, Gaussian optics such as those discussed above and shown in FIG. 11 may be used to focus the laser beam 114 from the CO2 laser to produce a laser beam focal point 116. The optical assembly 120 may be configured to position the laser beam focal point 116 on the outer surface 103 of the continuous glass tubing 101. Referring to FIG. 13, in embodiments, the laser beam steering device 126 may comprise a mirror galvanometer 126A which uses a pair of mirrors to steer the laser beam 114. Referring now to FIG. 14, in embodiments, the laser beam steering device 126 may comprise a polygon mirror 126B comprising faceted surfaces such that, as the polygon mirror 126B is rotated and the laser beam 114 contacts the facets at different points between the vertices connecting the facets, the angle in which the laser beam 114 reflects off of the polygon mirror 126B is changed between extremes defining the scanning field of the laser beam 114.

[0164] Referring now to FIGS. 15-17, to promote squareness of the cleaved tube end after separation, the optical assembly 120 of the laser system 110 may be configured to scan thelaser beam 114 at an angle a with respect to the center axis A of the continuous glass tubing 101. In this manner, the laser system 110 is able to create the scribe line SL such that the scribe line SL is perpendicular to the center axis A of the continuous glass tubing 101 while accounting for differences between the scan speed Viaser of the laser beam 114 and the tube speed Vtube at which the continuous glass tubing 101 is drawn through the system by the tube puller 130 (e.g., in units of linear meters per second). In embodiments, the tube speed Vtube at which the continuous glass tubing 101 is drawn through the system by the tube puller 130 may be greater than or equal to about 1.0 m / s (meters / second) and less than or equal to about 13 m / s. The scan speed Viaser of the laser beam 114 may correspond to the rate in which the laser beam 114 travels along the line path LP of the laser beam 114 (i.e., in units of linear distance traveled per time increment). In embodiments, the scan speed Viaser of the laser beam 114 may be greater than or equal to about 1.0 m / s and less than or equal to about 10 m / s. In embodiments, the scan speed Viaser of the laser beam 114 may be up to about 14 m / s. FIG. 15 schematically depicts how the laser beam steering device 126 may set the line path LP of the laser beam 114 when tube speed Vtube is less than the scan speed Viaser of the laser beam 114. As shown in FIG. 15, when tube speed Vtube is less than the scan speed Viaser of the laser beam 114, the line path LP of the laser beam 114 may be approximately perpendicular to the center axis A of the continuous glass tubing 101 for creating the scribe line SL such that the scribe line SL is perpendicular to the center axis A of the continuous glass tubing 101.

[0165] Referring now to FIG. 16, when tube speed Vtube is greater than the scan speed Viaser of the laser beam 114, scanning the laser beam 114 in a direction perpendicular to the center axis A may result in the scribe line SL being formed at an angle with respect to the center axis A, which upon separation, may lead to a jagged tube end for the separated glass tube 102. To reduce or prevent producing an angled scribe line SL, the line path LP of the laser beam 114 may be set at the angle a with respect to the center axis A of the continuous glass tubing 101, as shown in FIG. 17. The angle a may be calculated based on the scan speed Viaser of the laser beam 114 and the tube speed Vtube such that the scribe line SL is perpendicular to the center axis A of the continuous glass tubing 101. The angle a may be set my adjusting settings of the laser beam steering device 126. For example, in embodiments wherein the laser beam steering device 126 comprises a mirror galvanometer 126A, the settings of the mirror galvanometer 126A may be set to produce a line path LP of the laser beam 114 at the desired angle a with respect to the center axis A of the continuous glass tubing 101. In embodiments wherein the laser beam steering device 126 comprises a polygon mirror 126B, the orientation of the polygonmirror 126B may be adjusted to produce a line path LP of the laser beam 114 at the desired angle a with respect to the center axis A of the continuous glass tubing 101.

[0166] Referring now to FIG. 18, in embodiments, the optical assembly 120 may comprise a cylindrical lens 128 positioned in the path of the laser beam 114 and configured to convert the laser beam 114 into a focused line 129. In such embodiments, the laser beam 114 may be static, thereby avoiding the need for moving parts in the optical assembly 120. Relative to embodiments discussed herein utilizing Gaussian optics to transform the laser beam 114 into a Gaussian beam having a laser beam focal point, embodiments utilizing a cylindrical lens 128 to convert the laser beam 114 into the focused line 129 may require a greater beam output power due to the cylindrical lens 128 spreading the laser energy over a larger area. However, if the beam output power is appropriately selected, the focused line 129 may be used to form the scribe line SL as an ablated trench in the continuous glass tubing 101 in just a single exposure of the laser, without moving the laser system 110 or changing the beam path during operation. The laser source 112 may be any of the laser sources previously discussed herein, and the laser beam may have any of the features or characteristics previously discussed herein. In embodiments, the laser beam 114 may have a wavelength in a wavelength range within which the laser beam 114 is absorbed by the glass of the continuous glass tubing 101, via linear or nonlinear interaction, to heat the glass and does not pass through the glass to a significant extent. In embodiments, the laser source 112 may be a CO2 laser having a beam output power of 40 W to 600 W, and the wavelength of the laser beam 114 may be greater than or equal to 9.2 pm and less than or equal to 11.2 pm. However, it is contemplated that the beam output power and wavelength could be adjusted depending on parameters of the continuous glass tubing 101 and the tube speed Vtube in which the continuous glass tubing 101 i s drawn through the system by the tube puller 130.

[0167] In embodiments of the separating systems 100, the laser system 110 may further comprise a plurality of laser sources with corresponding optical assemblies, wherein the plurality of laser sources and optical assemblies may be operable to produce a plurality of laser beams and direct each of the plurality of laser beams to the outer surface 103 of the continuous glass tubing 101 to produce a plurality of scribe lines. In embodiments, the laser system 110 may be operable to produce a plurality of laser beams positioned at different angular positions about the center axis A of the continuous glass tubing 101 relative to the laser beam 114. The plurality of laser sources and corresponding optical assemblies may be distributed angularly around the circumference of the continuous glass tubing 101.

[0168] Referring now to FIG. 19, the laser system 110 may comprise the laser sources 112, 112a, and 112b, which produce laser beams 114, 114a, and 114b, respectively. The laser system 110 may comprise optical assemblies 120, 120a, and 120b associated with respective laser sources 112, 112a, and 112b, each of optical assemblies 120, 120a, and 120b comprising a collection of one or more optical components (e.g., lenses, mirrors, fdters, etc.) that modify one or more characteristics (e.g., shape, power density, power density distribution, etc.) of the respective laser beams 114, 114a, or 114b prior to the incidence of these laser beams on the outer surface 103 of the continuous glass tubing 101. Each of the optical assemblies in these embodiments may be configured according to any of the optical assemblies disclosed herein, and each of the laser sources in these embodiments may comprise the properties of any of the laser sources disclosed herein.

[0169] The laser sources 112, 112a, and 112b and corresponding optical assemblies 120, 120a, and 120b may be distributed around the circumference C of the continuous glass tubing 101. The laser system 110 may, therefore, be further configured to form a plurality of scribe lines SL distributed about the circumference C of the continuous glass tubing 101 by focusing each laser beam of the plurality of laser beams 114, 114a, 114b to be incident on the outer surface 103 of the continuous glass tubing 101. Each laser beam 114, 114a, 114b of the plurality of laser beams may be configured to be incident on less than respective halves of the circumference C of the continuous glass tubing 101.

[0170] In embodiments, the total number of laser beams incident on the outer surface 103 of the continuous glass tubing 101 may be 2, 3, 4, 5, 6, or more than 6 laser beams. In embodiments, the laser beams of the plurality of laser beams may be evenly spaced about the circumference C of the continuous glass tubing 101, for example, depending on the number of laser beams in the plurality of laser beams, at an angular spacing of 180°, 120°, 90°, 72°, or 60°. In embodiments, the laser beams of the plurality of laser beams may be irregularly spaced about the circumference C of the continuous glass tubing 101.

[0171] Referring again to FIG. 19, the optical assemblies 120, 120a, and 120b may comprise cylindrical lenses 128, 128a, and 128b, respectively. The cylindrical lens 128 may positioned in the path of the laser beam 114 and configured to convert the laser beam 114 into a focused line 129. The cylindrical lens 128a may positioned in the path of the laser beam 114a and configured to convert the laser beam 114a into a focused line 129a. The cylindrical lens 128b may positioned in the path of the laser beam 114b and configured to convert the laserbeam 114b into a focused line 129b. The optical assemblies 120, 120a, and 120b may cause the focused lines 129, 129a, and 129b to be incident on the outer surface 103 of the continuous glass tubing 101. With a synchronized single shots of each of the three laser sources 112, 112a, 112b, three scribe lines SL may be formed as ablated trenches on the outer surface 103 of the continuous glass tubing 101. Without wishing to be bound by theory, it is believed that in these multi-side scribing embodiments, the formation of multiple scribe lines around the circumference of the continuous glass tubing may make it easier to separate the glass tube from the continuous glass tubing and improve the tube end quality glass tubes produced therefrom.

[0172] Methods for separating continuous glass tubing 101 into individual lengths of the glass tubes 102 using the separating systems 100 disclosed herein will now be described in further detail. Referring again to FIG. 1, the methods for separating continuous glass tubing 101 disclosed herein may comprise passing the continuous glass tubing 101 through a laser system 110 operable to produce a laser beam 114. The methods may further comprises forming a scribe line SL in the continuous glass tubing 101 by focusing the laser beam 114 to be incident on an outer surface 103 of the continuous glass tubing 101. The laser system 110 may be configured to cause the laser beam 114 to be incident on less than half of a circumference of the continuous glass tubing 101. The methods may further comprises separating the continuous glass tubing 101 along the scribe line SL to produce a glass tube 102 having a fixed length L. The continuous glass tubing 101 may be passed through the laser system 110 by moving the continuous glass tubing 101 in a direction parallel to a center axis A of the continuous glass tubing 101. With reference to FIGS. 1, 3, and 4, moving the continuous glass tubing 101 in the direction parallel to the center axis A of the continuous glass tubing 101 may comprise pulling the continuous glass tubing 101 from a glass tube forming apparatus 220 through the laser system 110 using a tube puller 130.

[0173] The methods disclosed herein for separating continuous glass tubing 101 may comprise forming the scribe line SL over less than 180 degrees of the continuous glass tubing 101. The depth Dsof the scribe line SL may vary with angular position on the outer surface 103 of the continuous glass tubing 101. In embodiments, the scribe line SL formed by the methods disclosed herein may comprise a scribe line length Lsgreater than or equal to 0.001 times di, where di is an outer diameter of the continuous glass tubing 101. In embodiments, the scribe line SL formed by the methods disclosed herein may comprise a scribe line length Lsless than or equal to di.

[0174] The laser system 110 can include any of the components, features, or characteristics previously described herein for the laser system 110. In embodiments, the laser system 110 utilized in the methods disclosed herein may comprise a pulsed laser assembly and the laser beam 114 may be an ultrashort pulsed laser. The laser beam 114 may have any of the features and / or characteristics previously described for laser beam 114. In embodiments, the laser beam 114 produced by the laser system 110 may have a wavelength of from about 200 nm to about 1200 nm, such as about 1064 nm, about 532 nm, about 355 nm, or about 266 nm. Referring again to FIGS. 13 and 14, the laser system 110 utilized in the methods disclosed herein may comprise a laser source that is a CO2 laser. In embodiments, the wavelength of the CO2 laser may be greater than or equal to 9.2 pm and less than or equal to 11.2 pm. In embodiments, the CO2 laser may comprise a beam output power greater than or equal to 40 W and less than or equal to 600 W.

[0175] With reference still to FIGS. 13 and 14, the methods disclosed herein for separating continuous glass tubing 101 may comprise scanning the laser beam 114 across the outer surface 103 of the continuous glass tubing 101 with a laser beam steering device 126. In embodiments, scanning the laser beam 114 across the outer surface 103 of the continuous glass tubing 101 with the laser beam steering device 126 may comprise controlling movement of the laser beam 114 using a mirror galvanometer 126A or a polygon mirror 126B. Referring again to FIGS. 15- 17, scanning the laser beam 114 across the outer surface 103 of the continuous glass tubing 101 may comprise seaming the laser beam 114 at an angle a with respect to a center axis A of the continuous glass tubing 101 such that the scribe line SL is formed perpendicular to the center axis A of the continuous glass tubing 101.

[0176] Referring again to FIGS. 10A and 10B, the methods disclosed herein for separating continuous glass tubing 101 may comprise transforming the laser beam 114 into a Bessel beam defining a laser beam focal line 118, wherein the scribe line SL comprises a plurality of perforations 121 formed in the continuous glass tubing 101 by the laser beam focal line 118.

[0177] Referring again to FIGS. 11, 12A, and 12B, the methods disclosed herein for separating continuous glass tubing 101 may comprise transforming the laser beam 114 into a Gaussian beam defining a laser beam focal point 116, wherein the scribe line SL comprises an ablated trench 123 formed by the laser beam focal point 116. In embodiments, the methods disclosed herein may comprise forming the ablated trench 123 to have a trench width Tw greater than or equal to 20 pm and less than or equal to 50 pm. In embodiments, the methodsdisclosed herein may comprise forming the ablated trench 123 to have a trench width Tw greater than or equal to 100 pm and less than or equal to 300 pm.

[0178] Referring again to FIG. 18, the methods disclosed herein for separating continuous glass tubing 101 may comprise passing the laser beam through a cylindrical lens 128 that converts the laser beam 114 into a focused line 129, wherein the laser beam 114 is static.

[0179] Referring again to FIG. 19, the methods disclosed herein for separating continuous glass tubing 101 may comprise forming a plurality of scribe lines distributed about the circumference C of the continuous glass tubing 101 by focusing the laser beam 114 and each one of a plurality of laser beams 114a and 114b to be incident on less than respective halves of the circumference C of the continuous glass tubing 101. Each of the plurality of laser beams 114a and 114b may be positioned at a different angular position about a center axis A of the continuous glass tubing 101 relative to the laser beam 114.

[0180] Referring again to FIGS. 7A and 7B, the methods disclosed herein for separating continuous glass tubing 101 may comprise separating the continuous glass tubing 101 along the scribe line SL may comprise creating a tensile stress in the continuous glass tubing at the scribe line SL by applying a force to the continuous glass tubing 101 at a position downstream of the laser system 110. In embodiments, separating the continuous glass tubing 101 along the scribe line SL may comprise thermally shocking the continuous glass tubing 101 at the scribe line SL using thermal shock device 146. In embodiments, thermally shocking the continuous glass tubing 101 at the scribe line SL may comprise cooling the continuous glass tubing 101 at or near the scribe line SL. In embodiments, cooling the continuous glass tubing 101 at or near the scribe line SL may comprise spraying the continuous glass tubing 101 with the cooling fluid 147.EXAMPLES

[0181] The embodiments described herein will be further clarified by the following examples.EXAMPLE 1

[0182] In Example 1, a glass tube 102 was separated from continuous glass tubing 101 by using a Bessel beam to produce a scribe line SL in the outer surface 103 of the continuous glass tubing 101 and then allowing the cantilever effect caused by the weight of the unsupportedglass tubing downstream of the scribe line SL to induce a tensile stress at the scribe line SL causing fracture at the scribe line SL and separation of the glass tube 102 from the continuous glass tubing 101. In Example 1, the Bessel beam was an ultrashort pulsed laser having a wavelength of 1064 nm, a pulse duration of 10 picoseconds, a repetition rate of 100 kHz, and a scan speed of 1.0 meter per second.

[0183] A photograph of a section of continuous glass tubing 101 containing the scribe line SL formed in Example 1 is shown in FIG. 20. The scribe line length Lsfor the scribe line SL shown in FIG. 20 is 5.5 mm. The inset in FIG. 20 shows a magnified view of the scribe line SL in the continuous glass tubing 101 and reveals the plurality of perforations 121 forming the scribe line SL as a series of holes or channels through the glass of the continuous glass tubing 101. FIG. 21 A shows a photograph of an end view of the glass tube 102 after being separated from the continuous glass tubing 101 at the scribe line SL in FIG. 20. FIG. 21 A reveals a clean separation and demonstrates that the glass tube 102 can be separated in a controlled manner from the continuous glass tubing 101 despite the laser-induced scribe line SL being formed over just a portion of the circumference of the continuous glass tubing 101. FIG. 2 IB is a photograph showing a magnified end view of the glass tube 102 shown in FIG. 21 A, in the region corresponding with the dashed ellipse 152. It is evident from FIG. 21B that the perforations 121 in this example extend through the wall thickness T of the continuous glass tubing 101.EXAMPLE 2

[0184] In Example 2, a glass tube 102 was separated from continuous glass tubing 101 by using a Gaussian beam to produce a scribe line SL as an ablated trench 123 in the outer surface 103 of the continuous glass tubing 101 and then allowing the cantilever effect caused by the weight of the unsupported glass tubing downstream of the scribe line SL to induce a tensile stress at the scribe line SL causing fracture at the scribe line SL and separation of the glass tube 102 from the continuous glass tubing 101. In Example 2, the Gaussian beam was an ultrashort pulsed laser having a wavelength of 532 nm, a pulse duration of 10 picoseconds, and a repetition rate of 20 kHz. The Gaussian beam in Example 2 was scanned across the outer surface 103 of the continuous glass tubing 101 using a galvanometer. The ultrashort pulsed laser was sourced from an ultrafast diode-pumped solid state laser provided with a frequency doubler to generate the 532 nm wavelength.

[0185] A photograph of a section of continuous glass tubing 101 containing the scribe line SL formed as an ablated trench 123 in Example 2 is shown in FIG. 22. The ablated trench 123 in FIG. 22 has a trench length Lt of 5.4 mm and, as can be seen in the inset, a trench width Wt of 35 pm. FIG. 23A shows a photograph of an end view of the glass tube 102 after being separated from the continuous glass tubing 101 at the ablated trench 123 in FIG. 22. FIG. 23A reveals a clean separation and demonstrates that the glass tube 102 can be separated in a controlled manner from the continuous glass tubing 101 by forming a laser-induced scribe line SL as an ablated trench 123 over just a portion of the circumference of the continuous glass tubing 101. FIG. 23B is a photograph showing a magnified end view of the glass tube 102 shown in FIG. 23A, in the region corresponding with the dashed ellipse 154. FIG. 23B reveals a smooth cross-sectional plane of separation in regions of the continuous glass tubing 101 where the ablated trench 123 is not present.

[0186] FIG. 24 shows a photograph of glass tubes 102 after being separated from the continuous glass tubing 101 wherein the high-quality cleaved ends of the glass tubes 102 can be seen. The glass tubes 102 in FIG. 24 are separated by a broken tube fragment to provide a clearer view of the high-quality cleaved ends. As can be seen from FIGS. 23A, 23B, and 24, the cleaved tube ends of the present disclosure show little to no cracks, reduced chipping, and good squareness with respect to the center axis A of the continuous glass tubing 101.EXAMPLE 3

[0187] In Example 3, a glass tube 102 was separated from continuous glass tubing 101 by using a Gaussian beam to produce a scribe line SL as an ablated trench 123 in the outer surface 103 of the continuous glass tubing 101 and then allowing the cantilever effect caused by the weight of the unsupported glass tubing downstream of the scribe line SL to induce a tensile stress at the scribe line SL causing fracture at the scribe line SL and separation of the glass tube 102 from the continuous glass tubing 101. In Example 3 , the Gaussian beam was a pulsed CO2 laser modulated by a TTL square wave and having a wavelength of 10.6 pm, a repetition rate of 60 kHz, and a maximum beam output power of 400 W. As discussed above, using a laser having a wavelength that is absorbed by the glass of the continuous glass tubing 101, e.g., a CO2 laser having a wavelength of 10.6 pm, may allow the continuous glass tubing 101 to absorb most of the laser energy at the outer surface 103 (down to a few hundred micrometers) and the energy transfer can be very efficient. Due to the strong glass absorption at this wavelength, the glass temperature quickly rises and reaches the melting point of the glassthereby allowing the laser beam 114 to melt and evaporate the glass material in the scanned path to create the ablated trench 123. The Gaussian beam in Example 3 was scanned across the outer surface 103 of the continuous glass tubing 101 using a galvanometer.

[0188] A photograph of a section of continuous glass tubing 101 containing the scribe line SL formed as an ablated trench 123 in Example 3 is shown in FIG. 25. The ablated trench 123 in FIG. 25 has a trench length Lt of 7.2 mm, which corresponds to the diameter of the continuous glass tubing 101. As can be seen in the inset of FIG. 25, the ablated trench 123 formed by the CO2 laser in Example 3 has a trench width Wt of 190 pm. As discussed previously herein, the trench width Wt and trench depth Dt may be controlled by adjusting the wavelength, beam output power, and scan speed of the laser beam 114. FIG. 26A shows a photograph of an end view of the glass tube 102 after being separated from the continuous glass tubing 101 at the scribe line SL in FIG. 25. FIG. 26A reveals a clean separation and demonstrates that the glass tube 102 can be separated in a controlled maimer from the continuous glass tubing 101 by forming a CO2 laser-induced scribe line SL as an ablated trench 123 over just a portion of the circumference of the continuous glass tubing 101. FIG. 26B is a photograph showing a magnified end view of the glass tube 102 shown in FIG. 26A, in the region corresponding with the dashed ellipse 156, showing the cross-sectional plane of separation in more detail.

[0189] It should be understood that while the systems and methods of the present disclosure are discussed with respect to single-wall glass tubing, the systems and methods may also be used to separate laminated continuous glass tubing.

[0190] While various embodiments of the separating systems and methods for separating continuous glass tubing have been described herein, it should be understood that it is contemplated that each of these embodiments and techniques may be used separately or in conjunction with one or more embodiments and techniques.

[0191] It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modification and variations come within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A method for separating continuous glass tubing, the method comprising: passing the continuous glass tubing through a laser system operable to produce a laser beam; forming a scribe line in the continuous glass tubing by focusing the laser beam to be incident on a surface of the continuous glass tubing, wherein the laser system is configured to cause the laser beam to be incident on less than half of a circumference of the continuous glass tubing; and separating the continuous glass tubing along the scribe line to produce a glass tube having a fixed length.

2. The method of claim 1, wherein passing the continuous glass tubing through the laser system comprises moving the continuous glass tubing in a direction parallel to a center axis A of the continuous glass tubing.

3. The method of claim 2, wherein moving the continuous glass tubing in the direction parallel to the center axis A of the continuous glass tubing comprises pulling the continuous glass tubing from a glass tube forming apparatus through the laser system using a tube puller.

4. The method of claim 1, wherein the scribe line is formed over less than 180 degrees of the circumference of the continuous glass tubing.

5. The method of claim 1, wherein a depth of the scribe line varies with angular position on the surface of the continuous glass tubing.

6. The method of claim 1, wherein the scribe line comprises a scribe line length Lsgreater than or equal to 0.001 times di and less than or equal to di, where di is an outer diameter of the continuous glass tubing.

7. The method of claim 1, wherein the laser beam comprises a wavelength from about 2 pm to about 12 pm.

8. The method of claim 1, wherein the laser beam comprises a wavelength of 1064 nm, 532 nm, 355 nm, or 266 nm.

9. The method of claim 1, wherein the laser system comprises a pulsed laser assembly and the laser beam is an ultrashort pulsed laser.

10. The method of claim 9, further comprising transforming the laser beam into a Bessel beam defining a laser beam focal line, wherein the scribe line comprises a plurality of perforations formed in the continuous glass tubing by the laser beam focal line.

11. The method of claim 9, further comprising transforming the laser beam into a Gaussian beam defining a laser beam focal point, wherein the scribe line comprises an ablated trench formed by the laser beam focal point.

12. The method of claim 11, further comprising forming the ablated trench to have a trench width Tw greater than or equal to 20 pm and less than or equal to 50 pm.

13. The method of claim 11, wherein the laser system comprises a laser source, and wherein the laser source is a CO2 laser.

14. The method of claim 13, further comprising forming the ablated trench to have a trench width Tw greater than or equal to 100 pm and less than or equal to 300 pm.

15. The method of claim 13, wherein the laser beam comprises a beam output power greater than or equal to 40 W and less than or equal to 600 W.

16. The method of claim 13, wherein the laser beam comprises a wavelength greater than or equal to 9.2 pm and less than or equal to 11.2 pm.

17. The method of claim 13, further comprising passing the laser beam through a cylindrical lens that converts the laser beam into a focused line, wherein the laser beam is static.

18. The method of claim 1, further comprising scanning the laser beam across the surface of the continuous glass tubing with a laser beam steering device.

19. The method of claim 18, wherein scanning the laser beam across the surface of the continuous glass tubing with the laser beam steering device comprises controlling movement of the laser beam using a mirror galvanometer or a polygon mirror.

20. The method of claim 18, wherein scanning the laser beam across the surface of the continuous glass tubing comprises scanning the laser beam at an angle with respect to a center axis A of the continuous glass tubing such that the scribe line is formed perpendicular to the center axis A of the continuous glass tubing.

21. The method of claim 1, further comprising forming a plurality of scribe lines distributed about the circumference of the continuous glass tubing by focusing each one of a plurality of laser beams to be incident on less than respective halves of the circumference of the continuous glass tubing.

22. The method of claim 21, wherein each one of the plurality of laser beams is positioned at a different angular position about a center axis A of the continuous glass tubing relative to the laser beam.

23. The method of claim 1, wherein separating the continuous glass tubing along the scribe line comprises creating a tensile stress in the continuous glass tubing at the scribe line by applying a force to the continuous glass tubing at a position downstream of the laser system.

24. The method of claim 1, wherein separating the continuous glass tubing along the scribe line comprises thermally shocking the continuous glass tubing at the scribe line.

25. The method of claim 24, wherein thermally shocking the continuous glass tubing at the scribe line comprises cooling the continuous glass tubing at or near the scribe line.

26. The method of claim 25, wherein cooling the continuous glass tubing at or near the scribe line comprises spraying the continuous glass tubing with water mist.

27. A system for separating continuous glass tubing, the system comprising: a laser system comprising a laser source and an optical assembly, wherein the laser system is operable to produce a laser beam and configured to form a scribe line in the continuous glass tubing by focusing the laser beam to be incident on a surface of the continuous glass tubing, and wherein the laser system is configured to cause the laser beam to be incident on less than half of a circumference of the continuous glass tubing; a tube puller configured to pass the continuous glass tubing through the laser system; and a separating station configured to separate the continuous glass tubing along the scribe line to produce a glass tube having a fixed length.

28. The system of claim 27, wherein the tube puller is configured to pass the continuous glass tubing through the laser system by moving the continuous glass tubing in a direction parallel to a center axis A of the continuous glass tubing.

29. The system of claim 28, further comprising a glass tube forming apparatus positioned upstream of the laser system and the tube puller, wherein the tube puller is configured to pull the continuous glass tubing from the glass tube forming apparatus and through the laser system.

30. The system of claim 27, wherein the laser system is configured to form the scribe line over less than 180 degrees of the circumference of the continuous glass tubing.

31. The system of claim 27, wherein the laser system is configured to form the scribe line to have a depth that varies with angular position on the surface of the continuous glass tubing.

32. The system of claim 27, wherein the laser system is configured to form the scribe line to have a scribe line length Lsgreater than or equal to 0.001 times di and less than or equal to di, where di is an outer diameter of the continuous glass tubing.

33. The system of claim 27, wherein the laser beam comprises a wavelength from about 2 pm to about 12 pm.

34. The system of claim 27, wherein the laser beam comprises a wavelength of 1064 nm, 532 nm, 355 nm, or 266 nm.

35. The system of claim 27, wherein the laser system comprises a pulsed laser assembly and the laser beam is an ultrashort pulsed laser.

36. The system of claim 35, wherein the optical assembly comprises a collection of optical components configured to transform the laser beam into a Bessel beam defining a laser beam focal line, and wherein the laser system is configured to focus the Bessel beam to form the scribe line as a plurality of perforations in the continuous glass tubing.

37. The system of claim 35, wherein the optical assembly comprises a collection of optical components configured to transform the laser beam into a Gaussian beam defining a laser beam focal point, and wherein the laser system is configured to focus the Gaussian beam to form the scribe line as an ablated trench.

38. The system of claim 37, wherein the laser system is configured to form the ablated trench to have a trench width Tw greater than or equal to 20 pm and less than or equal to 50 pm.

39. The system of claim 37, wherein the laser source is a CO2 laser.

40. The system of claim 39, wherein the laser system is configured to form the ablated trench to have a trench width Tw greater than or equal to 100 pm and less than or equal to 300 pm.

41. The system of claim 39, wherein the laser source is configured to produce the laser beam to have a beam output power greater than or equal to 40 W and less than or equal to 600 W.

42. The system of claim 39, wherein the laser source is configured to produce the laser beam to have a wavelength greater than or equal to 9.2 pm and less than or equal to 11.2 pm.

43. The system of claim 39, further comprising a cylindrical lens positioned in a path of the laser beam and configured to convert the laser beam into a focused line, wherein the laser beam is static.

44. The system of claim 27, further comprising a laser beam steering device configured to scan the laser beam across the surface of the continuous glass tubing.

45. The system of claim 44, wherein the laser beam steering device is configured to control movement of the laser beam using a mirror galvanometer or a polygon mirror.

46. The system of claim 44, wherein the laser beam steering device is configured to scan the laser beam across the surface of the continuous glass tubing at an angle with respect to a center axis A of the continuous glass tubing such that the scribe line is formed perpendicular to the center axis A of the continuous glass tubing.

47. The system of claim 27, wherein the separating station comprises a mechanical stressing device configured apply a force to the continuous glass tubing at a position downstream of the laser system to create a tensile stress in the continuous glass tubing at the scribe line and separate the continuous glass tubing along the scribe line.

48. The system of claim 27, wherein the separating station comprises a thermal shock device configured to thermally shock the continuous glass tubing at the scribe line to separate the continuous glass tubing along the scribe line.

49. The system of claim 48, wherein the thermal shock device is configured to thermally shock the continuous glass tubing at the scribe line by cooling the continuous glass tubing at or near the scribe line.

50. The system of claim 49, wherein the thermal shock device is configured to cool the continuous glass tubing at or near the scribe line by spraying the continuous glass tubing with water mist.

51. The system of claim 27, wherein: the laser system further comprises a plurality of laser sources with corresponding optical assemblies; the laser system is further operable to produce a plurality of laser beams positioned at different angular positions about a center axis A of the continuous glass tubing relative to the laser beam; and the laser system is further configured to: form a plurality of scribe lines distributed about the circumference of the continuous glass tubing by focusing each of the plurality of laser beams to be incident on the surface of the continuous glass tubing; and cause each of the plurality of laser beams to be incident on less than respective halves of the circumference of the continuous glass tubing.

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