System and method for transforming glass tubes using millimeter-wave microwaves

Abstract

A method for producing a glass article from a glass tube is provided. The method includes securing the glass tube in a holder of a converter having multiple processing stations, including a heating station, a forming station, and a separation station. The method includes forming one or more features of the glass article at a working end of the glass tube by indexing the glass tube through the heating station and the forming station, separating the glass article from the working end of the glass tube in the separation station, and indexing the glass tube from the separation station to an auxiliary processing station that includes a heating station or a forming station. The method includes volumetrically heating a targeted heating area on the glass tube and the glass article using an electromagnetic heating device in at least one of the processing stations.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application No. 63 / 428,774, filed November 30, 2022, the contents of which are incorporated herein by reference in their entirety.

[0002] The present specification relates generally to systems and processes for producing glass articles from glass tubes, and specifically to glass tube converting systems and processes that involve using millimeter wave radiation to treat glass tubes in the converting system. [Background technology]

[0003] Historically, glass has been used as a preferred material for packaging pharmaceuticals due to its hermeticity, optical clarity, and superior chemical durability compared to other materials. Specifically, glass used in pharmaceutical packaging must have adequate chemical durability to prevent it from affecting the stability of the pharmaceutical formulations contained therein. Glasses with suitable chemical durability include glass compositions within the ASTM standard "Type IA" and "Type IB" glass compositions, which have a proven history of chemical durability.

[0004] Glass tubing can be converted into other glass articles, such as various glass containers for use in pharmaceutical applications, including, but not limited to, vials, syringes, ampoules, cartridges, and other glass articles. Glass tubing can be converted, for example, in a "converting machine." Converting machines have been in use for over 75 years and are currently made by various commercial and internal equipment suppliers. These converting machines typically use steps including flame processing, rotary and stationary tool forming, heat separation, or scoring and impact cutting steps to reshape long lengths of glass tubing into multiple glass articles. Various burners and forming tools are often used to shape one or more articles from the glass tubing and to separate the articles from the glass tubing. Summary of the Invention

[0005] According to an embodiment of the present disclosure, a method for producing multiple glass articles from a glass tube is provided. The method includes securing the glass tube in a holder of a converter having multiple processing stations, the multiple processing stations including multiple heating stations, at least one forming station, and a separation station, and the converter sequentially indexes the holder and the glass tube through each of the processing stations. The method includes forming one or more features of the glass article at a working end of the glass tube by indexing the glass tube through each of the multiple heating stations and the at least one forming station. The method further includes separating the glass article from the working end of the glass tube in the separation station and indexing the glass tube from the separation station to an auxiliary processing station disposed immediately downstream from the separation station, the auxiliary processing station including one of the multiple heating stations or at least one forming station. The method also includes volumetrically heating a targeted heating area on at least one of the glass tube and the glass article using an electromagnetic heating device in at least one of the processing stations.

[0006] According to an embodiment of the present disclosure, there is provided a converter for producing a plurality of glass articles from a glass tube, the converter including: a plurality of holders, each of the plurality of holders operable to secure a glass tube and rotate the glass tube about a central axis of the glass tube; a plurality of processing stations including a plurality of heating stations, at least one forming station, and a separation station, the converter operable to index the plurality of holders and the glass tube through each of the plurality of processing stations, the separation station operable to separate the glass article from the working end of the glass tube; the converter including an auxiliary processing station disposed immediately downstream from the separation station, the auxiliary processing station including one of the plurality of heating stations or one of the at least one forming station; and an electromagnetic heating device configured to heat the glass tube or glass article in at least one of the plurality of processing stations, the electromagnetic heating device configured to volumetrically heat the glass tube or glass article.

[0007] It is to be understood that both the foregoing general description and the following detailed description are intended to describe various embodiments and provide an overview or framework for understanding the nature and features 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 various embodiments described herein and, together with the description, serve to explain the principles and operation of the claimed subject matter. [Brief explanation of the drawings]

[0008] [Figure 1] 1A and 1B schematically depict a front view of an embodiment of a converter for producing glass articles from glass tubes according to one or more embodiments shown and described herein; [Figure 2]2A and 2B schematically depict a top view of the primary and secondary turrets of the converter of FIG. 1 with an auxiliary processing station immediately downstream from the separation station according to one or more embodiments shown and described herein. [Figure 3A] 2A and 2B schematically depict a heating station of the converter of FIG. 1 according to one or more embodiments shown and described herein. [Figure 3B] 1A and 1B schematically depict a perspective view of a row of glass tubes during a step of conversion according to one or more embodiments shown and described herein. [Figure 4] 2 schematically depicts one embodiment of a forming station of the converter of FIG. 1 according to one or more embodiments shown and described herein. [Figure 5] 2A and 2B schematically depict another embodiment of a forming station of the converter of FIG. 1 according to one or more embodiments shown and described herein. [Figure 6] 2 schematically depicts a separation station of the converter of FIG. 1 according to one or more embodiments shown and described herein. [Figure 7] 2A and 2B schematically depict a perspective view of a section of a glass tube in the converter of FIG. 1 before conversion, according to one or more embodiments shown and described herein; [Figure 8] 1 is a plot of the dielectric loss tangent of borosilicate glass versus microwave frequency according to one or more embodiments shown and described herein. [Figure 9] 10 is a graph of the volume loss density of a microwave source at different frequencies through a glass tube wall thickness according to one or more embodiments shown and described herein. [Figure 10] 10 illustrates numerical modeling results of instantaneous volume loss density due to a 150 GHz microwave source according to one or more embodiments shown and described herein. [Figure 11] 1 shows a modeled temperature distribution across a cross section of a glass tube during heating according to one or more embodiments shown and described herein. [Figure 12]10 illustrates a modeled temperature distribution across three glass tubes as a microwave beam is shaped into a strip, according to one or more embodiments shown and described herein. [Figure 13] 10 shows a modeled temperature distribution of a microwave beam penetrating three glass tubes according to one or more embodiments shown and described herein. DETAILED DESCRIPTION OF THE INVENTION

[0009] Reference will now be made in detail to embodiments of the presently disclosed systems and methods for converting glass tubing into glass articles, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like parts.

[0010] During the conversion of glass tubes into glass articles using a converting machine (i.e., a converter), heating elements such as burners heat the glass in the glass tube in one or more heating stations to a temperature where the viscosity of the glass allows the glass to be shaped into one or more features of the glass article. The shaping station includes shaping tools, such as pin and wheel assemblies, that contact the heated glass tube and shape the internal and external dimensions of the features of the finished glass article. Following the formation of the features in the working end of the glass tube, the glass article containing the shaped features is separated from the working end of the glass tube in a separation station and passed to a bottom forming machine. To heat the glass tube in the converter, gas burners are typically used in steps requiring heating, including preheating, separation, and shaping. Extensive heating is often required. For example, during the preheating stage, depending on the glass composition, the glass tube temperature may need to be increased by 1000°C or more, and further heating may be required in subsequent stations of the converter (e.g., to allow the glass article to be separated from the glass tube).

[0011] One of the challenges in existing conversion processes is manufacturing throughput. This challenge has been exacerbated by the recent increase in global demand for the mass production of vials for medical applications (e.g., vaccine vials), and the productivity of manufacturing equipment, including converters, can become a bottleneck in the production of vials and other glass articles. All known equipment designed for the mass production of vials and similar glass articles uses gas burners as the heat source for glass processing. The productivity, or production rate (parts per minute) of existing equipment, depends on many factors, including machine design details, equipment size, component reliability, material quality, process control, precision, maintenance frequency, production downtime, and other factors. One parameter common to all machines of this type and fundamental to throughput is the maximum glass heating rate, which is determined by the ability of the heat source (e.g., gas burner) to heat the glass parts to the appropriate processing temperature without damaging the parts. The limiting factor is that heat generated by the burner is first highly absorbed in the glass's skin layer and then transferred through the glass volume via thermally conductive mechanisms. All other things being equal, the rate and uniformity of heating of the glass are limiting factors in production throughput and are difficult to radically accelerate or improve.

[0012] In view of the above, embodiments of the present disclosure provide conversion systems and methods that use alternative heat sources for glass, allowing for uniform heating while also enabling higher heating rates. Specifically, embodiments of the present disclosure include heating glass using microwaves in the millimeter wavelength range. Millimeter wavelength radiation allows for high power and effective volumetric glass heating. Therefore, the systems and methods of the present disclosure include the use of a gyrotron microwave heating device to focus the heating to a focal region of the glass and volumetrically heat the glass at a fast rate.

[0013] A gyrotron is a high-power linear-beam vacuum tube that generates millimeter-wave electromagnetic waves through electron cyclotron resonance in a strong magnetic field. Gyrotrons operate at frequencies between 20 and 527 GHz, with output powers ranging from tens of kilowatts to one to two megawatts. Standard heating methods, such as gas burners or infrared heating, have significant limitations in achieving highly controlled, rapid heating. Gyrotron microwave heating, on the other hand, offers numerous advantages over these conventional heating methods. Under millimeter-wave electromagnetic radiation, glass can absorb electrical energy through the dipolar reorientation effect and convert it into internal energy. Unlike infrared heating, millimeter waves can penetrate glass materials to achieve volumetric heating. Therefore, gyrotron microwaves can generate a high-frequency internal energy source that heats glass volumetrically. Therefore, it is a more effective method for heating glass thickness at a higher rate than conventional infrared or convection heating, thereby improving heating efficiency, heating uniformity, and production throughput. While rapid bulk heating is possible and may be desirable for certain applications, millimeter-wave microwaves also allow precision with localized and / or targeted profile heating to a desired thermal state or profile. This capability allows for customized temperature and / or viscosity profiles from the center to the edge of the glass, optimizing the physical, mechanical, and / or optical properties of the glass. Additionally, the energy source can be focused solely on the glass without overheating surrounding materials, such as plastic or metal materials that may be used in production equipment (e.g., converters).

[0014] Because the millimeter-wave beam can be collimated, the heating device can focus directly on the target area to be heated within the glass tube and resulting article. Therefore, embodiments enable reduced energy waste compared to conventional heating sources (e.g., gas burners). By precisely controlling the target heating area, millimeter-wave sources can also help achieve highly accurate nominal design shapes that meet strict dimensional specifications. In theory, the control provided could also increase process repeatability and improve production yields. According to embodiments of the present disclosure, systems and methods are provided that enable increased glass tube heating rates compared to gas burners and other conventional methods. Improved heating rates can be achieved through the use of specific microwave frequencies, improved heating uniformity, and potentially simultaneous heating of multiple tubes using the same heating device. The systems and methods can be applied to a variety of glass compositions and geometries, including tubes and rods, to form various glass articles. Embodiments include using millimeter-wave generating devices to heat glass tubes in separating, melting, and forming operations.

[0015] According to an embodiment of the present disclosure, a converter for producing multiple glass articles from a glass tube is provided and may include a plurality of holders. Each of the plurality of holders may be operable to secure a glass tube and rotate the glass tube about a central axis of the glass tube. The converter may further include a plurality of processing stations, which may include a plurality of heating stations, at least one forming station, and a separation station. The converter may be operable to index the plurality of holders and the glass tube through each of the plurality of processing stations. The separation station may be operable to separate the glass article from the working end of the glass tube. The converter may further include an auxiliary processing station disposed immediately downstream from the separation station, which may include one of the plurality of heating stations or one of the at least one forming station. In an aspect of the embodiment, one or more of the plurality of processing stations may include a gyrotron microwave heating device capable of producing a microwave beam, including a millimeter-wavelength beam. Specifically, at least one of the plurality of heating stations, the at least one forming station, and the separation station may include a heating device capable of generating a millimeter-wavelength beam.

[0016] Separating the glass article from the working end of the glass tube may form a glass meniscus at the working end of the glass tube. The converter may further include a perforation device disposed between the separation station and the auxiliary processing station. The perforation device may be positioned to perforate a meniscus at the working end of the glass tube. The perforation device may include at least one perforation heating device for heating the meniscus at the working end of the glass tube. The perforation heating device may include a burner, such as a single or multi-point gas burner, or a plurality of such burners. According to aspects of the embodiment, the perforation heating device may include a gyrotron microwave heating device capable of producing a microwave beam including millimeter-wavelength waves. According to aspects of the embodiment, each of the multiple processing stations may be stationary, and the converter may continuously index the glass tube through each of the multiple processing stations.

[0017] According to an additional embodiment of the present disclosure, a method for producing a plurality of glass articles from a glass tube using a converter is provided. The method includes using a converter according to embodiments disclosed herein. The method may include securing a glass tube in a holder of the converter, indexing the glass tube through each of a plurality of heating stations and at least one forming station to form one or more features of the glass article at a working end of the glass tube, separating the glass article from the working end of the glass tube in a separation station, and indexing the glass tube from the separation station to an auxiliary processing station disposed immediately downstream of the separation station. The method may also include perforating a meniscus of the glass tube.

[0018] According to an additional embodiment of the present disclosure, a method for producing multiple glass articles from a glass tube may include securing the glass tube in a holder of a converter having multiple processing stations. The multiple processing stations may include multiple heating stations, at least one forming station, and a separation station, and the converter may sequentially index the holder and the glass tube through each of the processing stations. The method may further include forming one or more features of the glass article at a working end of the glass tube by indexing the glass tube through each of the multiple heating stations and the at least one forming station. The method may include separating the glass article from the working end of the glass tube in the separation station. Separating the glass article from the working end of the glass tube may form a glass meniscus at the working end of the glass tube. The method may further include indexing the glass tube from the separation station to an auxiliary processing station, which may be disposed immediately downstream of the separation station. The auxiliary processing station may be one of the multiple heating stations or one of the forming stations. The method may further include perforating the meniscus of the glass tube. Perforating the meniscus can open the working end of the glass tube. In an aspect of the embodiment, one or more of the plurality of processing stations can include a gyrotron microwave heating device capable of producing a microwave beam, including a millimeter-wavelength beam. Specifically, at least one of the plurality of heating stations, at least one forming station, the separating station, and the perforation device can include a heating device capable of generating a millimeter-wavelength beam.

[0019] 1 and 2, one embodiment of a converter 100 for producing multiple glass articles from a glass tube 102 is schematically depicted. The converter 100 includes multiple holders 130, each operable to secure a glass tube 102 and rotate the glass tube 102 about its central axis. The converter 100 further includes multiple processing stations 106, including multiple heating stations 202, at least one forming station 204, and a separation station 206, and the converter 100 is operable to index the multiple holders 130 and glass tubes 102 through each of the multiple processing stations 106. The separation station 206 may be operable to separate the glass article 103 from the working end of the glass tube 102, where separating the glass article 103 from the working end of the glass tube 102 forms a glass meniscus at the working end of the glass tube 102. The converter 100 may further include an auxiliary processing station 203 disposed immediately downstream from the separation station 206. The auxiliary processing station 203 may include one of the heating stations 202 or one of the forming stations 204. The converter 100 may further include a piercing station 212 disposed on the main circuit 116 after the separation station 206 in the direction of the index 222 of the main turret 108. At the piercing station 212, the meniscus at the working end of the glass tube 102 is pierced, thereby reopening the working end 150 of the glass tube 102.

[0020] The converter 100 disclosed herein may be used in a method for producing a plurality of glass articles 103 from a glass tube 102. The method may include securing the glass tube 102 in a holder 130 of the converter 100, which includes a plurality of processing stations 106, including a plurality of heating stations 202, at least one forming station 204, and a separation station 206. The converter 100 sequentially indexes the holder 130 and the glass tube 102 through each of the processing stations 106. The method may further include forming one or more features of the glass article 103 at a working end 150 of the glass tube 102 by indexing the glass tube 102 through each of the plurality of heating stations 202 and the at least one forming station 204 and separating the glass article 103 from the working end of the glass tube 102 in the separation station 206, wherein separating the glass article 103 from the working end of the glass tube 102 forms a glass meniscus at the working end of the glass tube 102. The method may further include indexing the glass tube 102 from the separation station 206 to an auxiliary processing station 203 disposed immediately downstream of the separation station 206, the auxiliary processing station 203 including one of the heating stations 202 or one of the forming stations 204. The method may further include perforating the formed meniscus at the working end of the glass tube. Perforating the meniscus opens the working end of the glass tube 102. The auxiliary processing station 203 may be the heating station 202 or the forming station 204.

[0021] Directional terms used herein, e.g., up, down, right, left, front, back, top, bottom, are used only with reference to the depicted figures and the coordinate axes provided therewith, and are not intended to imply absolute orientations.

[0022] Unless otherwise expressly stated, it is never intended that any method described herein be construed as requiring its steps to be performed in a particular order, or that any apparatus require a particular orientation. Thus, where a method claim does not actually recite the order in which its steps are to be followed, or where any apparatus claim does not actually recite an order or orientation for individual components, or where the claim or the specification otherwise specifically states that the steps are to be limited to a particular order, or where no particular order or orientation for the apparatus components is recited, no order or orientation is intended to be inferred in any sense. This applies to all possible implicit bases for interpretation, including logical considerations regarding the arrangement of steps, workflow, component order, or component orientation, the plain meaning derived from grammatical organization or punctuation, and the number or type of embodiments described herein.

[0023] 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" element includes aspects having two or more such elements unless the context clearly dictates otherwise.

[0024] As used herein, the "working end" of the glass tube is the end of the glass tube oriented relative to the holder toward the processing station in the converter's main turret, and the "non-working end" of the glass tube is the end of the glass tube oriented away from the processing station in the main turret.

[0025] As used herein, the "dwell time" of a converter refers to the duration that a glass tube spends in a particular processing station before passing to the next subsequent processing station. For indexing converters, the dwell time is the time that elapses from the first time that the glass tube reaches a rest position in the processing station to the second time that the glass tube begins to move out of the rest position toward the next processing station.

[0026] As used herein, the term "active time" refers to the duration of time that a glass tube is maintained in engagement with at least one heating element or at least one forming tool while in a particular processing station.

[0027] As used herein, the term "index time," when used in reference to an index converter, refers to the duration that a glass tube is translated from one processing station to the next processing station immediately downstream. "Dwell time," "active time," and "index time" are all measured in units of time.

[0028] When used in connection with a heating station, "engaging" a heating device with the glass tube 102 may refer to placing the heating device in a position where a flame and / or electromagnetic radiation from the heating device extends toward or contacts and heats the glass tube 102. Conversely, when the heating device is disengaged from the glass tube 102, the heating device is placed in a position where the flame or electromagnetic radiation from the heating device is directed away from the glass tube 102 or is moved sufficiently far away from the glass tube 102 so that the flame or electromagnetic radiation does not contact or directly heat the glass tube 102.

[0029] When used with respect to the forming tool 324 in the forming station 204, the term "engaged" refers to the forming tool 324 contacting the glass tube 102. When the forming tool 324 is disengaged, the forming tool 324 does not contact the glass tube 102.

[0030] As used herein, the term "part rate" refers to the production or throughput rate of a converter in units of number of glass articles per unit time.

[0031] As used herein, the term "circumference" of a glass tube refers to the set of points on the glass tube 102 at a certain radius r from the central axis D of the glass tube 102 up to 360 degrees from a particular Z position (i.e., a position on the + / -Z axis of the diagram). The circumference of the glass tube 102 may coincide, for example, with the outer surface 140 of the glass tube 102 at a particular Z position or the inner surface 146 of the glass tube 102 at a different Z position.

[0032] As used herein, the term "run" refers to the normal steady-state operation of the converter. Therefore, as used herein, "run setting" refers to the setting of the converter for the normal steady-state operation of the converter.

[0033] As used herein, the terms "upstream" and "downstream" refer to the positioning of a converter's processing stations relative to one another. If a glass tube encounters a second processing station before encountering a first processing station, the first processing station is considered "downstream" of the second processing station. Similarly, if a glass tube encounters the first processing station before encountering the second processing station, the first processing station is considered "upstream" of the second processing station.

[0034] Glass tubing can be converted into glass articles, specifically, glass articles for use in pharmaceutical applications, which may include, but are not limited to, vials, syringes, ampoules, cartridges, jars, and other glass articles. Glass tubing can be converted into these glass articles using converters, such as converting machines, that include multiple processing stations. The processing stations may include, but are not limited to, heating stations, forming stations, separating stations, punching stations, cooling stations, polishing stations, measuring stations, or other types of processing stations. Converting machines typically reshape long lengths of glass tubing into multiple glass articles using steps that include, but are not limited to, flame processing, rotary and stationary tool forming, separating (e.g., thermal separating or scoring and impact cutting steps), punching, cooling, measuring, or other processing steps. Thus, glass articles produced through the converting process performed on a converting machine are subjected to a series of flame burners, other heating elements, and forming tools to shape the glass tubing into specific shapes and dimensions and separate the formed glass articles from the working ends of the glass tubing.

[0035] Referring now to FIG. 1 , one embodiment of a converter 100 for producing glass articles from glass tubes 102 is schematically depicted. The converter 100 converts the glass tubes 102 into a plurality of glass articles. The converter 100 may include a base 104 having a plurality of processing stations 106 and a main turret 108 positioned on the base 104 and rotatable about a central axis A relative to the base 104. The converter 100 may further include a glass tube loading turret 110 positioned on the main turret 108 for feeding the glass tubes 102 into the main turret 108. The converter 100 may also include a plurality of secondary processing stations 112 on the base 104 and a secondary turret 114, which may be rotatable relative to the base 104.

[0036] As depicted generally in FIG. 1 , the base 104 of the converter 100 may be stationary, and the processing stations 106 may be coupled to an upper portion 105 of the base 104. The multiple processing stations 106 may be spaced apart from one another and disposed within a main circuit 116. In embodiments, the main circuit 116 may be circular, such that the main turret 108 indexes the glass tubes 102 through the multiple processing stations 106 by rotation of the main turret 108 about a central axis A. Alternatively, in embodiments, the main circuit 116 may be a linear arrangement of processing stations 106. While described herein with reference to a circular arrangement of processing stations 106, it is understood that the subject matter disclosed herein may apply equally well to converters having other arrangements of processing stations 106, such as linear, curved, or irregularly shaped arrangements of processing stations 106.

[0037] The type and / or shape of the glass article to be produced from the glass tube 102 may affect the total number of processing stations 106 in the converter 100. The number of processing stations 106 in the main turret 108 may be between 14 and 32 processing stations 106. While the converter 100 and conversion process are described herein in the context of the converter 100 having 16 processing stations 106 in the main circuit 116, it is understood that the converter 100 may have more or less than 16 processing stations 106 in the main circuit 116. The processing stations 106 of the converter 100 may include, by way of example and without limitation, one or more heating stations, forming stations, polishing stations, cooling stations, separation stations, measuring stations, tube loading stations, ejection stations, other processing stations, or combinations thereof, to produce a glass article from the glass tube 102. The type and / or shape of the article to be produced from the glass tube 102 may also affect the type of processing stations 106 and / or the order of the processing stations 106 of the converter 100 in the main circuit 116.

[0038] The main turret 108 is generally positioned on the base 104 and is rotatable relative to the base 104 about a central axis A. A drive motor (not shown) may be utilized to rotate the main turret 108 relative to the base 104. The main turret 108 includes a plurality of holders 130 configured to removably secure each glass tube 102 to the main turret 108 and rotate the glass tube 102. The holders 130 may include, but are not limited to, clamps, chucks, or other holding devices, or a combination of holding devices. The holders 130 may orient each glass tube 102 so that the glass tube 102 is generally parallel to the central axis A of the main turret 108. While the converter 100 is described herein in the context of a vertically oriented converter 100, it should be understood that the converter 100 may be oriented horizontally or at an angle such that the glass tubes 102 are non-vertical during processing. Each of the holders 130 may extend from the bottom portion 109 of the main turret 108 toward the base 104 (i.e., in the −Z direction relative to the coordinate axes of FIG. 1 ). Each holder 130 may be oriented to position the working end 150 of the glass tube 102 within or adjacent to each of the successive processing stations 106 of the main circuit 116 as the holder 130 is indexed to each of the successive processing stations 106. The vertical orientation of the glass tubes 102 allows the downwardly protruding portion of each glass tube 102 to be indexed sequentially through the processing stations 106.

[0039] The converter 100 of the present disclosure may be an indexing converter 100 in which the converter 100 progressively indexes each of a plurality of holders 130 through a plurality of processing stations 106. Indexing refers to a stepwise process of moving a glass tube 102 into a processing station 106, maintaining the glass tube 102 at a stationary XYZ position within the processing station 106 for a dwell time, and then indexing the glass tube 102 to the next processing station 106. During the dwell time, the glass tube 102 is processed within the processing station 106, such as, but not limited to, being heated, shaped, cooled, measured, separated, etc. During the index time, the holders 130 and glass tube 102 are translated between two immediately adjacent processing stations 106.

[0040] Each holder 130 may be individually rotatable relative to the main turret 108 to rotate the glass tube 102 about its central axis D, which may be generally parallel to the central axis A of the main turret 108. Each of the holders 130 may be operably coupled to a motor (not shown), continuous drive belt, or other drive mechanism for rotation of each of the holders 130 relative to the main turret 108. Rotation of the holders 130 allows rotation of the glass tube 102 about its central axis D relative to a stationary heating element, forming tool, cooling nozzle, or other feature of the processing station 106. In embodiments, the heating element and / or forming tool in the processing station 106 may be maintained in a fixed position relative to the glass tube 102, and rotation of the glass tube 102 about the central axis D may allow the entire circumference of the glass tube 102 to be exposed to the heating element or forming tool.

[0041] 1 and 2, as previously discussed, the converter 100 may include a plurality of spaced-apart secondary processing stations 112 disposed in a secondary circuit 118 (FIG. 2). The converter 100 may include a secondary turret 114 (FIG. 1) for indexing or sequentially moving articles 103 (FIG. 1) separated from the glass tubes 102 through the plurality of secondary processing stations 112. The secondary turret 114 may be rotated relative to the base 104 about a second axis B, which is generally parallel to the central axis A of the main turret 108. The secondary turret 114 may also include a plurality of holders 130 for holding the glass articles 103 and positioning them for sequential engagement with each of the secondary processing stations 112. The secondary turret 114 receives the glass articles 103 from the separation station 206 (FIG. 2) of the main turret 108 and, through rotation of the secondary turret 114, indexes or continuously translates the glass articles 103 through a plurality of secondary processing stations 112, discharging the finished glass articles 103 from the converter 100. While shown in a circular pattern, it will be understood that the secondary processing stations 112 may be arranged in a linear, curvilinear, or irregular configuration. In converters configured to produce glass vials, ampoules, jars, or other single-opening containers, the secondary processing stations 112, often collectively referred to as bottom forming machines, may be operable to form the bottom of the container.

[0042] The glass tube loading turret 110 may be positioned adjacent to the main turret 108 in a position where the glass tube loading turret 110 can load a new length of glass tube 102 into a holder 130 of the main turret 108 in at least one processing station 106. In an embodiment, the processing station 106 aligned with the glass tube loading turret 110 may be a tube loading station 214 ( FIG. 2 ). When the converter 100 has converted all or at least a portion of the glass tube 102 at a particular holder position 136 into one or more glass articles, the glass tube loading turret 110 may feed the new length of glass tube 102 through the top of the main turret 108 to the holder 130 at the holder position 136 when the holder position 136 is indexed to align with the tube loading station 214 ( FIG. 2 ). In an embodiment, the converter 100 may include an arm (not shown) movable between the main turret 108 and the glass tube loading turret 110. When the converter 100 has converted all or a portion of the glass tube 102 at a particular holder position 136, the arm may grab a new length of glass tube 102 from the glass tube loading turret 110 or other glass tube staging device and deliver the new length of glass tube 102 to the main turret 108 at the particular holder position 136. Other methods and apparatus for delivering the new length of glass tube 102 to the main turret 108 are contemplated.

[0043] 2, an example embodiment of a converter 100 of the present disclosure is schematically depicted. As shown in FIG. 2, the multiple processing stations 106 of the converter 100 may include, but are not limited to, one or more of a heating station 202, a forming station 204, a separating station 206, a polishing station 108, a cooling station 210, a drilling station 212, a tube loading station 214, an ejection station 216, a measuring station 218, a tube length drop station 220, other stations, and / or combinations of these stations.

[0044] 2 schematically depicts the arrangement of processing stations 106 of converter 100 having a main circuit 116 of 16 processing stations 106 and a secondary circuit 118 of eight secondary processing stations 112, although more or fewer processing stations 106 and secondary processing stations 112 are contemplated. As previously described, the processing stations 106 of the main circuit 116 may be evenly spaced and evenly distributed about the circular circuit, and the secondary processing stations 112 of the secondary circuit 118 may also be evenly spaced and evenly distributed about the circular circuit.

[0045] 2 may include one or more heating stations 202, one or more forming stations 204, a separation station 206, a piercing station 212, one or more cooling stations 210, a measuring station 218, a tube length drop station 220, a tube loading station 214, or other processing stations 106. With respect to the indexing 222 orientation of the main turret 108, the heating station 202 is generally positioned before each of the forming stations 204 and separation stations 206 to preheat a target area of ​​the glass tube 102 to a viscosity at which the glass becomes deformable and can be shaped or drawn and separated.

[0046] Referring again to FIG. 2 , the shaping station 204 of the main turret 108 may be positioned downstream of the separation station 106, one or more heating stations 202, or both, in the direction of index 222. The shaping station 204 repetitively shapes the glass tube 102 to form one or more features of the finished glass article. Specifically, the shaping station 204 of the main turret 108 may be configured to shape the working end 150 ( FIGS. 4 and 5 ) of the glass tube 102 to form features at one end of the glass article 103. The shaping station 204 or the polishing station 208 of the secondary turret 114 may shape the other end of the glass article 103, for example, the bottom of a vial, after the glass article 103 is separated from the glass tube 102. In an embodiment, the converter 100 may be used to produce vials from glass tubes 102, and the forming stations 204 of the converter 100 may include one or more shoulder forming stations, flange forming stations, flange finishing stations, or combinations thereof, with one or more heating stations 202 positioned before and between each of the forming stations 204.

[0047] The main circuit 116 may further include a measurement station 218, where at least one measurement device may be used to measure one or more attributes of the glass tube 102. The glass tube attributes may include, but are not limited to, one or more dimensions of the glass tube 102, or features of the glass article 103 formed by the forming station 204, one or more cosmetic attributes of the glass tube 102 or the glass article 103, or a combination thereof. The converter 100 may further include a cooling station 210, a tube length drop station 220, a tube loading station 214, or a combination thereof, between the forming station 204 and the separation station 206. At the separation station 206, the partially formed glass article is separated from the glass tube 102 (FIG. 1). In the case of glass vials, ampoules, jars, and other single-opening glass containers, the bottom of the container is simultaneously formed during separation. The separation station 206 may also be a processing station 106 where the partially formed glass articles, once separated, are transferred to a secondary turret 114 (FIG. 1) indexed through a secondary circuit 118 of the secondary processing station 112.

[0048] Referring again to FIG. 2 , the secondary processing stations 112 of the secondary circuit 118 may include one or more heating stations 202, forming stations 204, polishing stations 208, drilling stations 212, cooling stations 210, ejection stations 216, other processing stations, or combinations of secondary processing stations 112. The secondary turret 114 may rotate about axis B in a direction 224 opposite to that of the main turret 108. In embodiments, the secondary turret 114 may rotate in the same direction as the main turret 108. Although FIG. 2 depicts a secondary circuit having a circular arrangement of secondary processing stations 112, as discussed above, the secondary circuit may have secondary processing stations 112 positioned in other non-circular arrangements, such as linear, curved, irregular, or other arrangements. In embodiments, the secondary processing stations 112 of the secondary circuit 118 may be used to form one or more features of the glass article 103, such as a vial, an ampoule, a cartridge, or a syringe, at an end of the glass article 103 opposite the end formed by the main turret 108. For example, in some embodiments, the glass article 103 is a vial, and the forming station 204 of the secondary circuit 118 may form the bottom of the vial. Other features, such as features like ampoules, cartridges, and syringes, are also contemplated. The secondary circuit 118 may include one or more polishing stations 208 to finish the surface of the glass article. The secondary circuit 118 may further include multiple cooling stations 210 and a discharge station 216, at which the finished glass article 103 is discharged from the converter 100.

[0049] The above description of the processing stations 106 in the main circuit 116 and the secondary processing stations 112 in the secondary circuit 118 is in the context of converter 100 having 16 stations in the main circuit 116 and 8 stations in the secondary circuit 118. However, it is understood that more or fewer processing stations 106 and secondary processing stations 112 may be utilized to create other glass articles, such as vials having different shapes or features, or cartridges, syringes, ampoules, or other pharmaceutical glass articles. Additionally, it is understood that the processing stations 106 and secondary processing stations 112 may be arranged in any of several different orders and / or configurations to produce differently shaped or sized glass articles.

[0050] 3A, the heating devices 202 of the converter 100 are schematically depicted. Each of the heating devices 202 includes one or more microwave generating devices 301. A heating station 202 refers to a processing station in which a region of the glass tube 102 is heated by one or more of the microwave generating devices 301 to increase the temperature and / or reduce the viscosity of the glass. The heating devices 202 may be used in processing stations 202 in which the glass is heated without significantly changing the physical shape of the glass tube 102, or in processing stations 202 in which the shape of the glass tube 102 is changed (e.g., by removing a partially formed glass article from the working end of the glass tube 102, by changing the shape of the glass tube 102 by perforating the meniscus of the glass at the working end 150 of the glass tube, by shaping the glass tube 102 to at least partially form the glass article, or by at least partially forming the glass article after separation from the glass tube 102). Thus, the heating device 202 may be used in a variety of processing stations, including a heating station, a forming station, a separating station, a punching station, a cooling station, a polishing station, a measuring station, or other types of processing stations.

[0051] Referring again to FIG. 3A , the heating device 202 includes a beam outlet 302 configured to volumetrically heat the glass tube 102 with electromagnetic radiation. As used herein, "volumetric heating" refers to heating a volume of material (such as the glass tube 102) such that the electromagnetic radiation penetrates uniformly throughout the volume of the material. Volumetric heating therefore delivers energy evenly within the body of the material. In contrast, conventional conductive and convective heating rely on heating the surface temperature of the material. Thus, with conventional conductive and convective heating, the surface temperature of the material (such as the glass tube 102) increases much faster than the interior of the material.

[0052] As discussed above, the heating device 202 is an electromagnetic heating device that uses electromagnetic radiation to volumetrically heat the glass tube 102. In an embodiment, the electromagnetic radiation may be microwave, such that the heating device 202 is a gyrotron microwave heating device. It is also contemplated that the electromagnetic radiation may be visible light, ultraviolet light, infrared light, or any other radiation configured to volumetrically heat the glass tube 102.

[0053] In some embodiments, the heating device 202 comprises a high-power linear beam vacuum tube that generates millimeter-wave electromagnetic waves through cyclotron resonance of electrons in a strong magnetic field. In some embodiments, the electromagnetic radiation generated by the heating device 202 includes a microwave beam 304, which the heating device 202 directs outward from the beam outlet 302 toward a side of the glass tube 102, such as the first side 306 a or the second side 306 b of the glass tube 102. As shown in FIG. 3A, the beam outlet 302 is disposed on the first side of the glass tube 102 such that the beam outlet 302 directs the microwave beam 304 toward the first side 306 a, although it should be understood that the beam outlet 302 may be disposed on the second side of the glass tube 102. As also shown in FIG. 3B, the microwave beam 304′ may be focused into a stripe shape by the heating device 202. In some examples, the cross section of the microwave beam 304 comprises a width equal to or greater than the width of the glass tube 102, or equal to or greater than the width of multiple glass tubes positioned side by side.

[0054] As shown in FIG. 3B , in embodiments, the heating device 202 may be positioned to heat targeted regions of one or more glass tubes 102a-102e. This may be accomplished using a single microwave-generating device 301 configured to direct a microwave beam 304 at multiple glass tubes, or by incorporating multiple microwave-generating devices 301 within the heating device. Example embodiments include multiple microwave-generating devices 301 positioned to heat one or more glass tubes from the same side of the glass tube, or positioned to heat one or more glass tubes from opposite sides of the glass tube. In embodiments, the heating device 202 may include a mixture of different types of heating devices, including a microwave-generating device 301 and one or more gas burners, infrared burners, or other types of heating elements. These other types of burners may be fluidly coupled to a fuel gas supply, an oxygen supply, and optionally an air supply. Examples of fuel gases for the burners may include, but are not limited to, hydrogen, hydrocarbon fuel gases such as methane, propane, and butane, other fuel gases, or combinations thereof.

[0055] The electromagnetic radiation generated by the heating device 202 is approximately 1×10 5 W / m 2 More than 1 × 10 6 W / m 2 More than that, about 2 x 10 6 W / m 2 More than that, about 3 x 10 6 W / m 2 That's about 4 x 10 6 W / m 2 That's about 5 x 10 6 W / m 2 That's about 6 x 10 6 W / m 2 That's about 7 x 10 6 W / m 2 That's about 8 x 10 6 W / m 2 That's about 9 x 10 6 W / m 2 More than 1 × 10 7 W / m 2 More than 1 × 10 8W / m 2 or greater, or any range having any two of these values ​​as endpoints, e.g., about 1×10 5 W / m 2 ~Approx. 1×10 8 W / m 2 , about 2×10 6 W / m 2 ~Approx. 9×10 6 W / m 2 , or approximately 6 × 10 6 W / m 2 ~Approx. 8×10 6 W / m 2 Additionally, the electromagnetic radiation generated by the heating device 202 may include frequencies ranging from about 5 GHz to about 500 GHz, from about 5 GHz to about 400 GHz, from about 5 GHz to about 300 GHz, from about 10 GHz to about 300 GHz, from about 10 GHz to about 200 GHz, from about 25 GHz to about 200 GHz, from about 28 GHz to about 300 GHz, from about 30 GHz to about 150 GHz, from about 50 GHz to about 200 GHz, e.g., about 5 GHz, about 25 GHz, about 50 GHz, about 75 GHz, about 100 GHz, about 150 GHz, about 200 GHz, about 300 GHz, about 400 GHz, about 500 GHz, or any range having any two of these values ​​as endpoints, or any open range having either of these values ​​as a lower or upper limit.

[0056] Referring again to FIG. 3A , the converter 100 may further include a control structure 356 that includes an absorbing device 357, a shielding device 358, or both. For example, in the embodiment shown in FIG. 3A , the control structure 356 comprises an absorbing device 357 surrounded by a shielding device 358. In some embodiments, the shielding device 358 includes a metallic material, such as stainless steel, to reduce and / or prevent any electromagnetic leakage, such as microwave leakage. The absorbing device 357 may include, for example, a carbon-based foam absorber, a water jacket, or a combination thereof, to absorb electromagnetic radiation and thereby reduce and / or prevent any electromagnetic leakage, such as microwave leakage. Additionally, the beam outlet 302 of the heating device 202 may extend into the control structure 356, for example, such that the microwave beam 304 is contained within the control structure 356, which helps to direct the microwave beam 304 toward a target area of ​​the glass tube 102 and minimize electromagnetic wave propagation away from the target area and outside of the control structure 356. For example, the control structure 356 may include a hole into (or through) which the beam outlet 302 extends or is otherwise coupled.

[0057] As discussed above, some embodiments of the converter 100 include one or more secondary heating devices that can assist in the heating step in any one of the processing stations. The secondary heating devices can be disposed before or after the beam outlet 302 along the path traveled by the glass tube 102. The multiple secondary heating devices can include one or more conduction heaters, convection heaters, infrared heaters, resistance heaters, induction heaters, flame heaters, or the like. The secondary heating devices can be configured to simultaneously heat the glass tube 102 during volumetric heating by the heating device 202. As an aspect of an embodiment of the present disclosure, the heating step performed in one or more processing stations of the converter 100 can include volumetric heating of the glass tube 102 using the heating device 202. In some embodiments, the heating step includes volumetric heating of the glass tube 102 using the heating device 202 and heating of the glass tube 102 using one or more secondary heaters.

[0058] Because volumetric heating increases the temperature of the glass at a faster rate than traditional conduction and convection heating techniques, volumetric heating, as disclosed herein, may require a reduced heating period to reach the desired temperature and viscosity. For example, during volumetric heating using the heating device 202, the temperature of the glass tube 102 in the target heating area can increase at an average heating rate of about 5°C / sec or more, about 10°C / sec or more, about 15°C / sec or more, about 20°C / sec or more, about 30°C / sec or more, about 40°C / sec or more, about 50°C / sec or more, about 60°C / sec or more, about 70°C / sec or more, about 80°C / sec or more, about 90°C / sec or more, about 100°C / sec or more, for example, about 5°C / sec to about 100°C / sec, about 10°C / sec to about 90°C / sec, about 20°C / sec to about 80°C / sec, about 30°C / sec to about 80°C / sec, about 40°C / sec to about 80°C / sec, about 50°C / sec to about 80°C / sec, or any range having any two of these values ​​as endpoints. During volumetric heating, the temperature of the glass tube 102 in areas other than the target heating area may increase at an average heating rate that is lower than the heating rate of the target heating area. For example, the average heating rate may be about 0.3, or about 0.4, or about 0.5, or about 0.6, or about 0.7, or about 0.8, or about 0.9 times lower than the average heating rate of the target heating area. The rapid heating provided by embodiments herein may enable a target heated area of ​​a glass tube to be heated to a desired temperature in about 0.1 seconds to about 30 seconds, about 0.1 seconds to about 20 seconds, about 0.1 seconds to about 10 seconds, about 0.1 seconds to about 7.5 seconds, about 0.5 seconds to about 7.5 seconds, about 1 second to about 7.5 seconds, about 1.5 seconds to about 6 seconds, about 1.5 seconds to about 5 seconds, about 0.5 seconds to about 5 seconds, or any range having any two of these values ​​as endpoints, or any open range having either of these values ​​as a lower or upper limit.

[0059] It is also contemplated that the frequency of the electromagnetic radiation generated from the heating device 202 can be correlated to the thickness and / or shape of the target glass to provide optimal energy absorption in the glass. More specifically, the frequency of the electromagnetic radiation can be selected to substantially match or be the same as the thickness of the selected portion of the glass. When the frequency matches the thickness of the selected portion of the glass, the glass absorbs the electromagnetic radiation at an optimal absorption rate across that thickness. When the frequency of the electromagnetic radiation is higher or lower than the thickness of the selected portion of the glass, the glass absorbs the electromagnetic radiation at an absorption rate below optimal absorption. For example, if the target heating area of ​​the glass is a portion of the glass having a thickness of approximately 2 mm, the frequency of the electromagnetic radiation can be selected to be approximately 2 mm or less (which is equivalent to approximately 56 GHz or greater) to provide optimal energy absorption in the glass. Additionally, embodiments include selecting a frequency that evenly heats opposing sides of a hollow glass tube or evenly heats the glass tube around its entire circumference.

[0060] Embodiments of the present disclosure include directing or shaping a millimeter-wavelength beam to a target area of ​​a glass tube to heat. Because a millimeter microwave beam can be collimated, it can be focused directly onto the target area to be heated. This not only improves the precision of heating, but also wastes less energy in the process compared to, for example, a gas burner. By precisely controlling the target heating area, a microwave heat source can achieve a highly accurate nominal design shape for the finished glass article that meets strict dimensional specifications. This precision of the microwave beam can also increase process repeatability and improve production yields.

[0061] Embodiments of the systems and methods disclosed herein include using microwave-generating devices to heat glass tubes or articles in different configurations. For example, a microwave-generating device can heat a single glass tube or article, or a group of glass tubes or articles, where the group includes one or more rows of tubes, columns, or clusters of glass tubes. Designing the glass tube configuration involves choosing an optimized frequency selection, calculating the absorption rate of each tube, and designing the beam-shaping optics. The ability to heat multiple tubes allows for increased processing throughput due to higher energy utilization.

[0062] 4 and 5, an example of a forming station 204 of the converter 100 is schematically depicted. The forming station 204 refers to a processing station where one or more features of a glass article are formed proximate the working end 150 of the glass tube 102 through contact of the glass tube 102 with one or more forming tools 324. The forming station 204 does not include the separation station 206 or the punching station 212. Each forming station 204 includes one or more forming tools 324 that are rotatable about a tool axis E relative to the base 104 (FIG. 1). As the glass tube 102 passes through the forming station 204, the glass tube 102, which was heated in the previous heating station 202 or separation station 206, is rotated by the holder 130. The forming tools 324 engage with the glass tube 102 as it rotates. Once engaged, contact between the forming tools 324 and the heated glass tube 102 can form the glass tube 102 into a desired shape. The forming tool 324 may contact the glass tube 102 during the forming tool's 324 active time. At the end of the active time, the forming tool actuator 326 may remove the forming tool 324 from engagement with the glass tube 102. FIG. 4 schematically illustrates an embodiment of a forming station 204 for forming the shoulder 142 of a glass vial. FIG. 5 schematically depicts an exemplary embodiment of a forming station 204' for forming the flange 144 of a glass vial. The forming station 204' for forming the flange 144 comprises three forming tools 324a, 324b, and 324c. Other types of forming tools 324 may be employed within the forming station 204 depending on the desired features of the glass article 103.

[0063] 4 , the forming tool actuator 326 may be operable to move the forming tools 324 into and out of engagement with the glass tube 102. Moving the forming tools 324 into and out of engagement with the glass tube 102 may control the timing of contact between the forming tools 324 and the glass tube 102. The timing of contact between the forming tools 324 and the glass tube 102 refers to the timing of engagement and disengagement of each of the forming tools 324 in the forming station 204 with the glass tube 102. Adjusting the contact timing of the forming tools 324 may adjust the total active time of each of the forming tools 324 in contact with the glass tube 102, the contact sequence of the forming tools 324 with the glass tube 102, or both. As previously discussed, active time refers to the duration of time that at least one of the forming tools 324 is engaged with or in contact with the glass tube 102. The contact sequence between the shaping tools 324 and the glass tube 102 refers to the timing of engagement and disengagement between each individual shaping tool 324 in the shaping station 204 and the glass tube 102. Referring to FIG. 5 , in some cases, the contact sequence may be adjusted so that each of the shaping tools 324 a, 324 b, and 324 c initially contacts the glass tube 102 at the same instant. In other examples, the contact sequence may be adjusted so that the shaping tool 324 c (pin) contacts the inner surface of the glass tube 102 before or after the shaping tools 324 a and 324 b (wheels) contact the outer surface of the glass tube 102 at the beginning of the active time. The contact sequence may also include the order in which each of the shaping tools 324 a, 324 b, and 324 c disengages from the glass tube 102 at the end of the active time. The term “contact timing” is intended to include both the total active time and / or the contact sequence of the shaping tools 324 and the glass tube 102.

[0064] The forming tool actuators 326 may be operable to change the forming position of the forming tool 324 vertically (e.g., in the + / −Z direction of the coordinate axes in FIG. 3A ), horizontally (e.g., in the XY plane identified by the coordinate axes in FIG. 4 ), or a combination of these directions relative to the glass tube 102 in the forming station 204. The forming position of the forming tool 324 refers to the position of the forming tool 324 when it engages with the glass tube 102. In embodiments, each forming tool actuator 326 may include one or more servo motors operable to automatically and / or incrementally adjust the position of the forming tool 324 in one or more directions of the coordinate axes in FIG. 4 . Any other type of positioning device that is commercially available or to be commercially available may be used as at least a portion of the forming tool actuators 326.

[0065] Referring now to FIG. 6, an embodiment of the separation station 206 of the converter 100 is schematically depicted. The separation station 206 depicted in FIG. 6 is a thermal separation station and may be positioned behind one or more heating stations 202 in the direction of the index 222 of the main turret 108. The heating station 202 positioned before the separation station 206 heats the glass tube 102 in the separation region of the glass tube to make the glass viscous. The separation station 206 may include a separation heating device 340. The separation heating device 340 may have any of the features previously described for the heating device 302, including, but not limited to, a microwave generating device 301 or a gas burner, including associated valves and controls. While the glass tube 102 is rotated about central axis D by holder 130 while rendered viscous and deformable by the previous heating station 202, a separation heating device 340 may engage the glass tube 102 in a separation region to heat the glass tube 102 to a temperature at which the viscosity of the glass causes the partially formed glass article to separate from the glass tube 102. Once separated from the glass tube 102, the partially formed article may be transferred to secondary turret 114 (FIG. 1) or ejected from converter 100. In an embodiment, the partially formed glass article may be transferred to secondary holder 342 for further processing on secondary circuit 118.

[0066] 3-6 include schematic illustrations of several different example processing stations 106 that may be utilized in converter 100. However, it should be understood that other processing stations 106 having different structures, combinations of structures, or functions, such as cooling stations, measuring stations, polishing stations, or other processing stations 106, may be utilized to achieve the desired conversion of glass tube 102 into one or more glass articles.

[0067] Referring now to FIG. 7 , the glass tube 102 comprises a long, hollow, cylindrical tube made of glass. The glass tube 102 has a circular cross-sectional shape and comprises an outer surface 140, an inner surface 146, and a thickness t. The thickness t of the glass tube 102 refers to the radial distance between the inner surface 146 and the outer surface 140 of the glass tube 102. The glass tube 102 may have a length L measured in the + / −Z direction of the coordinate axes of FIG. 7 . The length L of the glass tube 102 decreases as the glass article 103 is gradually removed from the working end 150 of the glass tube 102 during the converting process. The glass tube 102 may have an outer diameter OD, as shown in FIG. 7 . As discussed above, the glass tube 102 is rotated about its central axis D throughout the converting process. The working end 150 of the glass tube 102 is the end of the glass tube 102 that is oriented in the −Z direction of the coordinate axes in FIG. 7 when the glass tube 102 is secured to the holder 130 of the converter 100. The non-working end of the glass tube 102 is the end opposite the working end 150 (i.e., the end of the glass tube 102 in the +Z direction of the coordinate axes in FIG. 2). Although the working end 150 is shown as the lowermost end of the glass tube 102, it will be understood that the converter 100 may be configured to orient the working end 150 of the glass tube 102 in an upward, horizontal, or other direction.

[0068] 1 and 2, the converter 100 may be an indexing converter in which each of a plurality of processing stations 106 is stationary and the converter 100 sequentially indexes the glass tube 102 through each of the plurality of processing stations 106. During operation, the converter 100 indexes the glass tube 102, which is secured in the holder 130, into the processing stations 106. At each processing station 106, a specific operation, such as heating, forming, separating, cooling, polishing, dropping, loading, measuring, etc., may be performed on the glass tube 102. The converter 100 may be timed so that all of the processing stations 106 complete their operations within a dwell time. At the end of the dwell time, the converter 100 indexes the glass tube 102 to the next processing station 106 in the main circuit 116. For an indexing converter, the total time per part per station, as used in this disclosure, is the sum of the dwell time and the index time. At separation station 206 , the partially finished glass article 103 is separated from the working end 150 of the glass tube 102 and transferred to a secondary processing station 112 in the secondary circuit 118 .

[0069] An example of a converter 100 for converting glass tubes 102 into glass vials includes a Vial Forming Machine Models RP16 or RP18 with an Automatic Tube Feeder manufactured by AMBEG Dr. J. Dichter GmbH, which includes 16 processing stations 106 in a main circuit 116 and eight secondary processing stations 112. Other examples include a Vial Forming Machine Model RP32 manufactured by AMBEG Dr. J. Dichter GmbH, which includes 32 processing stations 106 in a main circuit 116 and two secondary circuits 118 with eight secondary processing stations 112 in each secondary circuit 118, and a Zeta 098 Vial Forming Machine manufactured by Euromatic SRL, which includes 36 processing stations. Another example may include a Zeta 103 Cartridge Forming Machine manufactured by Euromatic SRL, which is a converter for converting glass tubes into glass cartridges. The cartridge converter has similar properties to the previously described vial converter 100, however, the cartridge converter is utilized to produce glass articles having a glass cartridge configuration rather than a glass vial.

[0070] Although described in the context of a converter 100 for producing glass vials from glass tubes 102, it should be understood that the converter 100 described herein may be configured to produce one or more other articles, such as other types of pharmaceutical containers or articles, by modifying the forming tools 324 and / or the order or configuration of the processing stations 106 in the main circuit 116 or the secondary processing stations 112 in one or more secondary circuits 118. The pharmaceutical articles may include, but are not limited to, vials, cartridges, syringes, ampoules, jars, or other glass pharmaceutical articles. In embodiments, the converter 100 disclosed herein may be configured to produce single-opening glass containers, such as, but not limited to, vials, ampoules, jars, or other glass containers, where the bottom of the glass container is formed through thermal separation of the glass article from the working end 150 of the glass tube 102.

[0071] 6 , during thermal separation of the partially formed glass article 103 from the working end 150 of the glass tube 102 in the separation station 206, the glass is heated by the separation heating device 340 until the glass becomes sufficiently viscous for the glass to separate from the working end 150 of the glass tube 102. In embodiments, the viscosity of the glass may be such that gravity alone may be sufficient to separate the partially formed glass article from the working end 150 of the glass tube 102. In embodiments, the partially finished glass article 103 may be pulled downward to separate the partially finished glass article 103 from the glass tube 102. The thermal separation in the separation station 206 results in forming a glass film over the upwardly facing end of the partially formed glass article 103 and on the new working end 150 of the glass tube 102. The glass film on the upwardly facing end of the partially formed glass article 103 forms the bottom of glass articles, including vials, ampoules, jars, and other single-opening containers. On the working end 150 of the glass tube 102, a glass film closes the working end 150 of the glass tube 102. As used throughout this disclosure, the term "meniscus" is used to refer to a glass film formed horizontally (e.g., perpendicular to the central axis D of the glass tube 102) across the working end 150 of the glass tube 102. Before further heating and forming the next glass article 103 at the working end 150 of the glass tube 102, the glass meniscus must be perforated at the working end 150 to reopen the working end 150 of the glass tube 102.

[0072] As used herein, a "piercing station" refers to a processing station 106 where the glass meniscus 350 at the working end 150 of the glass tube 102 is pierced. According to an embodiment, the piercing may be performed at the piercing station during the dwell time of the converter 100. According to another embodiment, the piercing may be performed at least partially during the index time of the converter 100 as the glass tube 102 is indexed from one processing station to the next. The piercing station 212 may include a piercing heating device positioned to heat the glass meniscus at the working end 150 of the glass tube 102. During operation, the converter 100 indexes the glass tube 102 directly from the separation station 206 to the piercing station 212. In the piercing station 212, the meniscus of the glass tube 102, previously formed in the separation station 206, is pierced by heating the meniscus in the piercing station 212, thereby reopening the working end 150 of the glass tube 102. Alternatively, the perforation of the meniscus can be performed while indexing the glass tube 102 from one processing station to the next.

[0073] According to an embodiment, the perforation may be formed by the heating device 202 disclosed herein. For example, the perforation may be performed by a burner oriented to direct a flame to contact the meniscus of the glass at the working end 150 of the glass tube 102. In an embodiment, a microwave generating device 301 is used to heat the working end 150 of the glass tube 102, thereby perforating the meniscus. The microwave generating device may direct a beam from below the working end (i.e., the -Z direction in FIG. 3A ) to above (the +Z direction) the meniscus. In another embodiment, the microwave generating device 301 may be positioned on the side of the glass tube (as shown in FIG. 3A ) and direct a beam of appropriate frequency and energy to perforate the meniscus at the working end 150 of the glass tube. For example, the microwave generating device 301 may direct the beam substantially horizontally (in the XY plane of FIG. 3A) to heat the center of the meniscus, or the microwave generating device 301 may be oriented at an angle to heat the meniscus at the working end 150 of the glass tube 102. As described herein, the frequency and energy of the microwave beam 304 may be selected to preferentially heat the meniscus rather than the sidewalls of the glass tube, or to specifically target the center of the meniscus.

[0074] The perforation device can be any device capable of perforating the meniscus formed at the working end 150 of the glass tube 102. Perforation devices suitable for perforating the meniscus can include, but are not limited to, a perforation burner, a laser, a suction device, a positive pressure airflow device, a mechanical device, a gyrotron microwave generator, or a combination thereof.

[0075] In embodiments, the meniscus may be perforated by directing a flow of gas, such as compressed air, nitrogen, argon, or other gas, at or across the meniscus. In embodiments, a suction device may be used to create a negative pressure large enough to perforate the meniscus. In embodiments, mechanical means or other methods may be used to perforate the meniscus instead of using a perforation heating device. Various methods of perforating the meniscus are described in U.S. Patent No. 10,968,133, entitled "METHODS FOR MINIMIZING SHR IN GLASS ARTICLES BY PRODUCING A GAS FLOW DURING PHARMACEUTICAL PART CONVERTING," which granted on April 6, 2021; co-pending U.S. application Ser. No. 16 / 197,187, entitled "SYSTEMS AND METHODS FOR MINIMIZING SHR FROM PIERCING DURING PHARMACEUTICAL PART CONVERTING USING A GAS FLOW," which filed on November 20, 2018; and co-pending U.S. application Ser. No. 16 / 197,187, entitled "SYSTEMS AND METHODS FOR MINIMIZING SHR FROM PIERCING DURING PHARMACEUTICAL PART CONVERTING USING NEGATIVE PRESSURE," which filed on November 21, 2018. No. 16 / 197,971, filed November 21, 2018, entitled "SYSTEMS AND METHODS FOR MINIMIZING SHR FROM PIERCING FROM PHARMACEUTICAL PART CONVERTING USING PULSED EJECTION," the entire contents of all of which are incorporated herein by reference.

[0076] The converter 100 may be used in a method for producing multiple glass articles from a glass tube. The method for producing multiple glass articles from a glass tube 102 may include securing the glass tube 102 in a holder 130 of the converter 100. The converter 100 may include any of the features of the converter 100 previously described herein. The converter 100 may include multiple processing stations 106, which may include multiple heating stations 202, at least one of a forming station 204, and a separation station 206. The converter 100 sequentially indexes the holder 130 and the glass tube 102 through each of the processing stations 106. The method may further include indexing the glass tube 102 through each of the multiple heating stations 202 and at least one forming station 204, and then separating the glass article from the working end 105 of the glass tube 102 in a separation station 206, thereby forming one or more features of the glass article at the working end 150 of the glass tube 102. Separating the glass article from the working end 150 of the glass tube 102 forms a glass meniscus at the working end 150 of the glass tube 102. The method may further include indexing the glass tube 102 from the separation station 206 to an auxiliary processing station 203 disposed immediately downstream of the separation station 206, and perforating the meniscus. The auxiliary processing station 203 may be one of the multiple heating stations 202 or one of the forming stations 204. Perforating the meniscus opens the working end 150 of the glass tube 102.

[0077] Separating the glass article from the working end 150 of the glass tube 102 may include thermally separating the partially formed glass article from the working end 150 of the glass tube 102. With reference to FIG. 6 , thermally separating the partially formed glass article from the glass tube 102 may include heating a separation region of the glass tube 102 using a separation cheering device 340 in the separation station 206, where the heating increases the viscosity of the glass in the separation region of the glass tube 102 to a point where gravity causes the partially formed glass article to separate from the working end 150 of the glass tube 102. In some embodiments, the partially formed glass article may be pulled gradually away from the working end 150 of the glass tube 102 during heating by the separation heating device 340. The thermal separation in the separation station 206 forms a meniscus of glass on the working end 150 of the glass tube 102. [Example]

[0078] The following examples illustrate the operation of the disclosed converter and method for producing multiple glass articles from a glass tube. The following examples are not intended to limit the scope of the present disclosure.

[0079] The glass tubes in these examples were borosilicate glass manufactured by Corning Incorporated. However, embodiments are not intended to be limited to borosilicate glass and may include, for example, aluminosilicate glass tubes, such as VALOR® glass manufactured and sold by Corning Incorporated. Aluminosilicate glass tubes may be further processed after conversion by annealing and / or ion-exchanging the glass tube. The effectiveness of the systems and methods disclosed herein does not depend on the type or composition of the glass. Thus, embodiments of the present disclosure may use borosilicate glass, aluminoborosilicate glass, aluminosilicate glass, fluorosilicate glass, phosphosilicate glass, fluorophosphate glass, sulfosulfate glass, germanate glass, vanadate glass, borate glass, phosphate glass, or titanium-doped silica glass, etc.

[0080] Microwaves are electromagnetic (EM) waves in the frequency range of 0.3 GHz to 300 GHz. The mechanism of microwave heating is the effect of microwave absorption due to dielectric loss. Under a microwave field, the inherent dipole moments or generated induced dipole moments in dielectric materials interact with the alternating EM field and reorient themselves to align with the high-frequency EM field, resulting in the energy conversion from electrical energy to heat. EM waves consist of oscillating electric field components (E) and magnetic field components (H). The governing equations for the EM field are based on Maxwell's equations, shown in Equations (1) and (2).

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[0081] Glass is non-magnetic and its magnetic permeability is negligibly small. In a uniform EM field, the power dissipated in glass per unit volume, P(r), is given by the following equation (Equation (4)):

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[0082] The heat transfer equation describes the spatial and temporal behavior of the temperature field in a medium exposed to microwave radiation (Equation (5)).

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[0083] Microwaves are v =3×10 8 m / s travels at the speed of light in a vacuum. Considering a glass medium with a refractive index of n = 2.62, the dielectric constant is ε = n 2 = 6.85. The speed of light in glass is

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[0084] Because the electrical conductivity of dielectric materials is typically much smaller than the dipole reorientation effect, the relative electrical loss factor becomes the primary material attribute for microwave absorption. For most dielectric materials, the dielectric constant (or relative permittivity) is close to a constant in the gyrotron frequency range. The loss tangent (tan δ) of a material then determines its ability to absorb microwaves. Figure 8 plots the frequency-dependent loss tangent of borosilicate glass based on experimental data. Data below 60 GHz were measured in experiments conducted for this disclosure, while data above 100 GHz are from the reference "Miscellaneous data on materials for millimeter and submillimeter optics." The existing measurement data was based on room temperature conditions. Borosilicate has relatively low microwave absorption compared to soda-lime glass and Corning® Gorilla® glass, but higher absorption than silica. For higher energy utilization and heating efficiency, it is ideal to employ higher frequency gyrotrons (100 GHz to 300 GHz). Typically, glasses exhibit higher absorption at elevated temperatures. As frequency increases, the loss tangent increases. This means that the material has higher absorption at the higher frequency end, from 90-150 GHz.

[0085] The volume loss density through the thickness of the glass can be calculated based on Mawell's equation. At a given frequency and wall thickness, a sinusoidal energy profile can be generated. Figure 9 shows the volume loss density distributions of different microwave sources across a 1.3 mm-walled borosilicate tube for frequencies of 30 GHz, 60 GHz, 90 GHz, and 150 GHz. A higher conversion rate of microwave energy into internal energy in the glass can be achieved through higher-frequency microwave sources. The plot in Figure 9 also demonstrates excellent energy penetration through the glass thickness, demonstrating that volumetric heating of the tube with high thermal uniformity is possible. For example, for a 1.3 mm-walled borosilicate tube, as shown in Figure 9, more than two cycles are generated through the wall thickness at frequencies higher than 60 GHz, but less than one cycle is generated at 30 GHz. Given low attenuation, a profile with more oscillations and less attenuation helps achieve better thermal uniformity. Higher frequencies also lead to higher energy absorption rates. In practice, a balance between absorption rate and uniformity must be maintained. A higher absorption rate is not always beneficial because it may cause overheating of the skin layer of the glass tube, resulting in poor thermal uniformity.

[0086] Borosilicate glass has a dielectric constant of 4.45 and a loss tangent of 0.01-0.02 in the 30-150 GHz range, with a corresponding power penetration depth of 80-8 mm. Because of the slow power decay in this frequency range, microwave energy can be uniformly converted within the glass tube wall thickness (submillimeter to millimeter) when the beam is incident perpendicularly to the side wall, and the transmitted energy can also simultaneously heat the far wall of the glass tube. Higher volume loss densities can be achieved by using high-frequency microwaves for wall thicknesses on the order of 1-2 mm. The improved relative loss factor above 100 GHz allows for a high rate of conversion of electromagnetic energy into internal energy in the glass.

[0087] The borosilicate glass was modeled using COMSOL Multiphysics® software (from COMSOL, Inc.). The modeled glass tube had an outer diameter of 29.5 mm and a wall thickness of 1.3 mm. Using a 150 GHz and 40 kW millimeter-wave source, a radiation intensity of 1.5E9 W / m 3 A volumetric loss density (VLD) exceeding 1000°C can be generated in both walls. Figure 10 shows the results of numerical modeling of the instantaneous volumetric loss density using this 150 GHz source. The results demonstrate that microwaves can penetrate and convert heat from both the near and far sides of the tube. It took only 14 seconds to raise the tube temperature from room conditions to over 1,000°C. While rotating the tube, a millimeter-wave beam was applied to confirm that the entire periphery was heated uniformly with a temperature gradient of less than 10°C (see Figure 11). Figure 11 shows the tube temperature distribution during heating while the tube was rotating. Depending on the gyrotron power, a temperature increase from room temperature to over 1,000°C can be achieved in a few seconds to a few tens of seconds. Thermal uniformity around the glass periphery is within 10°C.

[0088] As discussed herein, alternative configurations can be designed to improve production throughput, such as stripe beam heating of a single row of tubes, as modeled in FIG. 12. FIG. 12 shows that embodiments of the present disclosure can be expanded to process multiple tubes simultaneously when the beam is shaped into a stripe. The results in FIG. 12 were from modeling illustrating the electric field and corresponding tube temperature when heating three rows of tubes. Because only 26% of the energy is absorbed when EM transmits through each wall in a 150 GHz gyrotron, a two-row configuration can be designed to fully utilize the energy. In FIG. 13, an example three-row configuration was modeled using the same frequency and power source. The modeling results in FIG. 13 show that at least two rows of tubes can be heated simultaneously with greater thermal uniformity. Because power decay occurs beyond three rows, the outer layer tubes will not heat as much in this example. Here, FIG. 13 shows that similar heating temperatures can be achieved in the first two rows, but the temperature drops in the third row due to energy decay. If a lower frequency is chosen, for example 90 GHz, the absorption is reduced (about 11%) and it may be possible to heat four or five rows simultaneously.

[0089] While various embodiments of the converter 100 and systems and methods for producing multiple glass articles 103 from a glass tube 102 are described herein, it is understood that each of these embodiments and techniques may be used separately or in conjunction with one or more other embodiments and techniques.

[0090] It will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments described herein without departing from the spirit or scope of the claimed subject matter. Thus, it is intended that the present specification cover modifications and variations of the various embodiments described herein, provided that such modifications and variations come within the scope of the appended claims and their equivalents.

[0091] Exemplary Implementations Below are descriptions of various embodiments of the disclosed subject matter. Each embodiment may include one or more of various features, characteristics, or advantages of the disclosed subject matter. The embodiments are intended to illustrate some aspects of the disclosed subject matter and should not be considered a comprehensive or exhaustive description of all possible embodiments.

[0092] Aspect 1 relates to a method for producing a plurality of glass articles from a glass tube, the method including: securing the glass tube in a holder of a converter having a plurality of processing stations, the plurality of processing stations including a plurality of heating stations, at least one forming station, and a separation station; the converter sequentially indexing and securing the holder and glass tube through each of the processing stations; forming one or more features of the glass article at a working end of the glass tube by indexing the glass tube through each of the plurality of heating stations and the at least one forming station; separating the glass article from the working end of the glass tube in the separation station; indexing the glass tube from the separation station to an auxiliary processing station disposed immediately downstream of the separation station, the auxiliary processing station including one of the plurality of heating stations or at least one forming station; and volumetrically heating a targeted heating area on at least one of the glass tube and the glass article using an electromagnetic heating device in at least one of the processing stations.

[0093] Aspect 2 relates to the method of aspect 1, further comprising heating the glass tube or glass article such that during volumetric heating, the average temperature of the targeted heated area increases at a heating rate of about 15°C / sec or greater.

[0094] Aspect 3 relates to the method of aspect 1 or aspect 2, wherein the electromagnetic heating device is a gyrotron microwave heating device.

[0095] Example 4 relates to a method according to Example 3, wherein during volumetric heating, the gyrotron microwave heating device generates electromagnetic radiation having a frequency between about 28 GHz and about 300 GHz.

[0096] Aspect 5 relates to the method of any one of Aspects 1-4, wherein the wall thickness of the glass tube or glass article is about equal to or greater than the wavelength of the electromagnetic radiation generated from the electromagnetic heating device.

[0097] A sixth aspect relates to the method of any one of the first to fifth aspects, wherein the glass article comprises a pharmaceutical packaging container.

[0098] Aspect 7 relates to the method of aspect 6, wherein the glass article comprises a vial, a cartridge, a syringe, an ampoule, or a jar.

[0099] Example 8 relates to the method of any one of Examples 1 to 7, wherein during volumetric heating, the temperature of the glass tube or glass article is increased from room temperature to greater than 1000°C in less than 2 minutes, less than 1 minute, less than 30 seconds, or less than 15 seconds.

[0100] Aspect 9 relates to the method of any one of aspects 1-8, wherein during volumetric heating, the surroundings of the glass tube or glass article within the targeted heating area have a temperature variation of about 10° C. or less.

[0101] Aspect 10 relates to the method of any one of aspects 1-9, wherein the volumetric heating comprises simultaneously heating multiple glass tubes or multiple glass articles using a beam from an electromagnetic heating device.

[0102] Example 11 relates to the method of Example 10, further comprising shaping the beam from the electromagnetic heating device into a strip to heat multiple glass tubes or multiple glass articles simultaneously.

[0103] Example 12 relates to a method according to any one of Examples 1 to 11, wherein separating the glass article from the working end of the glass tube forms a glass meniscus at the working end of the glass tube, and the method further includes perforating the meniscus, wherein perforating the meniscus opens the working end of the glass tube.

[0104] Aspect 13 relates to the method of any one of aspects 1-12, wherein the electromagnetic heating device is used in at least one of the forming station, the separating station, the heating station, and the punching station.

[0105] Aspect 14 relates to a converter for producing a plurality of glass articles from a glass tube, the converter comprising: a plurality of holders, each of the plurality of holders operable to secure a glass tube and rotate the glass tube about a central axis of the glass tube; a plurality of processing stations including a plurality of heating stations, at least one forming station, and a separation station, wherein the converter is operable to index the plurality of holders and the glass tube through each of the plurality of processing stations, the separation station being operable to separate the glass article from the working end of the glass tube; the converter comprising an auxiliary processing station disposed immediately downstream from the separation station, the auxiliary processing station including one of the plurality of heating stations or one of the at least one forming station; and an electromagnetic heating device configured to heat the glass tube or glass article within at least one of the plurality of processing stations, wherein the electromagnetic heating device is configured to volumetrically heat the glass tube or glass article.

[0106] Example 15 relates to the converter of Example 14, further comprising one or more secondary heating devices configured to simultaneously heat the glass tube or glass article with the electromagnetic heating device.

[0107] Aspect 16 relates to the converter of aspect 15, wherein the one or more secondary heating devices include at least one of a conduction heater, a convection heater, an infrared heater, a resistance heater, an induction heater, and a flame heater.

[0108] Example 17 relates to the converter of any one of Examples 14 to 16, wherein the electromagnetic heating device is configured to generate electromagnetic radiation having a frequency between about 5 GHz and about 500 GHz.

[0109] An eighteenth embodiment relates to the converter of any one of the fourteenth to seventeenth embodiments, wherein the electromagnetic heating device is a gyrotron microwave heating device.

[0110] A nineteenth aspect relates to the converter of any one of the fourteenth to eighteenth aspects, wherein the beam from the electromagnetic heating device is configured to heat multiple glass tubes or multiple glass articles simultaneously.

[0111] Aspect 20 relates to the converter of aspect 19, further comprising beam shaping optics for shaping the beam from the electromagnetic heating device into a stripe for heating a plurality of glass tubes or a plurality of glass articles.

Claims

1. 1. A method for producing a plurality of glass articles from a glass tube, the method comprising: Fixing the glass tube in a holder of a converter having a plurality of processing stations, the plurality of processing stations including a plurality of heating stations, at least one forming station, and a separation station, the converter sequentially indexing the holder and the glass tube through each of the processing stations; forming one or more features of a glass article at a working end of the glass tube by indexing the glass tube through each of the plurality of heating stations and the at least one forming station; Separating the glass article from the working end of the glass tube in the separation station; indexing the glass tube from the separation station to an auxiliary processing station disposed immediately downstream of the separation station, the auxiliary processing station including one of the plurality of heating stations or one of the at least one forming station; and volumetrically heating a targeted heating area on at least one of the glass tube and the glass article using an electromagnetic heating device in at least one of the processing stations.

2. 10. The method of claim 1, further comprising heating the glass tube or glass article such that during the volumetric heating, the average temperature of the target heating area increases at a heating rate of about 15°C / sec or greater.

3. The method of claim 1 or 2, wherein the electromagnetic heating device is a gyrotron microwave heating device.

4. The method of claim 3 , wherein during the volumetric heating, the gyrotron microwave heating device generates electromagnetic radiation having a frequency between about 28 GHz and about 300 GHz.

5. The method of any one of claims 1 to 4, wherein the wall thickness of the glass tube or glass article is approximately equal to or greater than the wavelength of the electromagnetic radiation generated from the electromagnetic heating device.

6. The method of any one of claims 1 to 5, wherein the glass article comprises a pharmaceutical packaging container.

7. The method of claim 6 , wherein the glass article comprises a vial, cartridge, syringe, ampoule, or jar.

8. 8. The method of any one of claims 1 to 7, wherein during the volumetric heating, the temperature of the glass tube or the glass article is increased from room temperature to above 1000°C in less than 2 minutes, less than 1 minute, less than 30 seconds, or less than 15 seconds.

9. 9. The method of claim 1, wherein during the volumetric heating, the surroundings of the glass tube or glass article in the target heating area have a temperature fluctuation of about 10° C. or less.

10. The method of any one of claims 1 to 9, wherein the volumetric heating comprises simultaneously heating multiple glass tubes or multiple glass articles using a beam from the electromagnetic heating device.

11. 11. The method of claim 10, further comprising shaping the beam from the electromagnetic heating device into a strip to heat the plurality of glass tubes or the plurality of glass articles simultaneously.

12. 12. The method of claim 1, wherein separating the glass article from the working end of the glass tube forms a glass meniscus at the working end of the glass tube, and the method further comprises perforating the meniscus, wherein perforating the meniscus opens the working end of the glass tube.

13. The method according to any one of claims 1 to 12, wherein the electromagnetic heating device is used in at least one of a forming station, a separating station, a heating station and a perforation station.

14. 1. A converter for producing a plurality of glass articles from a glass tube, said converter comprising: a plurality of holders, each of the plurality of holders operable to secure a glass tube and rotate the glass tube about a central axis of the glass tube; a plurality of processing stations including a plurality of heating stations, at least one forming station, and a separation station; the converter is operable to index the plurality of holders and glass tubes through each of the plurality of processing stations; the separation station is operable to separate the glass article from the working end of the glass tube; the converter includes a plurality of auxiliary processing stations disposed immediately downstream from the separation station, the auxiliary processing station including one of the plurality of heating stations or one of the at least one forming station; an electromagnetic heating device configured to heat the glass tube or the glass article in at least one of the plurality of processing stations, the electromagnetic heating device configured to volumetrically heat the glass tube or the glass article.

15. 15. The converter of claim 14, further comprising one or more secondary heating devices configured to simultaneously heat the glass tube or the glass article with the electromagnetic heating device.

16. The converter of claim 15 , wherein the one or more secondary heating devices include at least one of a conduction heater, a convection heater, an infrared heater, a resistance heater, an induction heater, and a flame heater.

17. A converter according to any one of claims 14 to 16, wherein the electromagnetic heating device is configured to generate electromagnetic radiation having a frequency of between about 5 GHz and about 500 GHz.

18. Converter according to any one of claims 14 to 17, wherein the electromagnetic heating device is a gyrotron microwave heating device.

19. A converter according to any one of claims 14 to 18, wherein the beam from the electromagnetic heating device is configured to heat multiple glass tubes or multiple glass articles simultaneously.

20. 20. The converter of claim 19, further comprising beam shaping optics for shaping the beam from the electromagnetic heating device into a stripe for heating the glass tubes or glass articles.

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