Methods to control shape uniformity in glass tube converting processes

Patent metadata

Field	Value
Publication number	US-11970418-B2
Application number	US-202117398058-A
Country	US
Kind code	B2
Filing date	Aug 10, 2021
Priority date	Aug 12, 2020
Publication date	Apr 30, 2024
Grant date	Apr 30, 2024

Abstract

Methods for producing glass articles from glass tube includes securing a glass tube in a holder of a converter; rotating the glass tube; and passing the glass tube through processing stations, which include at least a heating station and a forming station, to form one or more features at a working end of the glass tube. An active time is an amount of time the glass tube is engaged with a heating element or a forming tool while in a processing station, and an exposure index for the processing station is the rotational speed of the glass tube multiplied by a number of heating elements or forming tools in the processing station multiplied by the active time. An absolute difference between the exposure index and a nearest integer is less than or equal to 0.30, which reduces temperature and dimensional inhomogeneity around a circumference of the glass tube.

First claim

What is claimed is:

1. A method for producing a plurality of glass articles from glass tube, the method comprising:
securing a glass tube in a holder of a converter comprising a plurality of processing stations, the processing stations comprising at least one heating station and at least one forming station;
rotating the glass tube about a center axis of the glass tube in the holder;
passing the glass tube through each of the plurality of processing stations to form one or more features at a working end of the glass tube, wherein, for any one of the plurality of processing stations:
an active time of the processing station is an amount of time the glass tube is maintained in engagement with at least one heating element or at least one forming tool while in the processing station;
an exposure index for the processing station is equal to a rotational speed of the glass tube within the holder multiplied by a number of heating elements or a number of forming tools in the processing station and multiplied by the active time of the glass tube in the processing station; and
an absolute difference between the exposure index and a nearest integer is less than or equal to 0.30; and

controlling the converter with a system controller communicatively coupled to the converter, the system controller comprising at least one processor and at least one non-transitory storage medium containing computer readable and executable instructions which, when executed by the processor, cause the system controller to automatically perform the following steps:
identifying one or more temperature or dimensional inhomogeneity in the glass tube around a circumference of the glass tube;
determining the exposure index of the glass tube for one or more of the plurality of processing stations;
comparing the exposure index for each of the one or more processing stations to the nearest integer; and
adjusting the rotational speed of the glass tube, the active time of the glass tube in the processing stations, or both to maintain the absolute difference between the exposure index and the nearest integer less than or equal to 0.30.

2. The method of claim 1 , comprising maintaining the exposure index within +/−0.30 of the nearest integer, wherein maintaining the exposure index within +/−0.30 of the nearest integer reduces instability in rotation of the glass tube and variations in temperature circumferentially around the glass tube.

3. The method of claim 1 , comprising maintaining the active time constant for each of the plurality of glass tubes in each of the plurality of processing stations and adjusting a rotational speed of each of the plurality of glass tubes to maintain the absolute difference between the exposure index and the nearest integer less than or equal to 0.30 for each of the plurality of glass tubes in each of the plurality of processing stations to reduce temperature and dimensional inhomogeneity in the glass tube around a circumference of the glass tube.

4. The method of claim 1 , comprising changing an active time for each of the plurality of glass tubes in one or more of the plurality of processing stations to maintain the absolute difference between the exposure index and the nearest integer less than or equal to 0.30 for each of the plurality of glass tubes in each of the plurality of processing stations to reduce temperature and dimensional inhomogeneity in the glass tube around a circumference of the glass tube.

5. A system for producing a plurality of glass articles from glass tube, the system comprising:
a converter having a plurality of processing stations comprising at least one heating station, at least one forming station, and a separating station;
a plurality of holders, each of the plurality of holders operable to secure a glass tube and rotate the glass tube about a center axis of the glass tube; and
a system controller communicatively coupled to the converter;
wherein the converter is operable to move the plurality of holders and glass tubes through the plurality of processing stations;
wherein each of the plurality of processing stations has an exposure index defined as a rotational speed of the glass tube within the holder in units of rotations per time multiplied by a number of heating elements or a number of forming tools contacting an outer surface of the glass tube in the processing station and multiplied by the active time of the glass tube in the processing station;
wherein an absolute difference between the exposure index and a nearest integer is less than or equal to 0.30 for each of the plurality of processing stations; and
wherein the system controller comprising at least one processor and at least one non-transitory storage medium containing computer readable and executable instructions which, when executed by the processor, cause the system controller to automatically:
identify one or more temperature or dimensional inhomogeneity in the glass tube around a circumference of the glass tube;
determine an exposure index of the glass tube for one or more of the plurality of processing stations;
compare the exposure index for each of the one or more processing stations to a nearest integer; and
adjust a rotational speed of the glass tube, an active time of the glass tube in the processing stations, or both to maintain an absolute difference between the exposure index and the nearest integer less than or equal to 0.30.

6. The system of claim 5 , wherein the at least one heating station of the converter comprises at least one swivel burner operatively coupled to a swivel burner actuator operable to pivot the swivel burner into and out of engagement with the glass tube in the at least one heating station to change the active time of the glass tube in the at least one heating station.

7. The system of claim 5 , wherein the at least one heating station of the converter comprises a burner translation system operable to translate at least one burner horizontally or vertically into and out of engagement with the glass tube to change the active time of the glass tube in the at least one heating station.

8. The system of claim 5 , wherein the at least one forming station of the converter comprises at least one forming tool operatively coupled to a forming tool actuator operable to translate the forming tool into and out of engagement with the glass tube to change the active time of the glass tube in the at least one forming station.

9. The system of claim 5 , wherein the converter comprises a measuring system operable to determine at least a temperature of the glass tube, at least a dimension of the glass tube, or combinations of these around a circumference of the glass tube.

10. The system of claim 5 , wherein the computer readable and executable instructions, when executed by the processor, cause the system to adjust the rotational speed of the glass tube to adjust the exposure index for one or a plurality of the processing stations.

11. The system of claim 5 , wherein the computer readable and executable instructions, when executed by the processor, cause the system to adjust the active time in one or more processing stations to adjust the exposure index.

12. The system of claim 5 , wherein the computer readable and executable instructions, when executed by the processor, cause the system to automatically adjust the active time of the at least one heating station by modifying the timing of moving the heating elements into and out of engagement with the glass tube.

13. The system of claim 5 , wherein the at least one heating station comprises a swivel burner operatively coupled to a swivel burner actuator, wherein the swivel burner actuator is co

Assignees

• Corning Inc

Inventors

• Fournel Olivier
• Mcnelis Kevin Patrick

Classifications

• C03B23/08 Primary

  to exact dimensions, e.g. calibrating · CPC title

• C03B23/043

  Heating devices specially adapted for re-forming tubes or rods in general, e.g. burners · CPC title

• C03B23/094

  by centrifuging · CPC title

• C03B23/04 Primary

  Re-forming tubes or rods · CPC title

• C03B23/045

  Tools or apparatus specially adapted for re-forming tubes or rods in general, e.g. glass lathes, chucks (C03B23/043 takes precedence) · CPC title