Methods to control shape uniformity in glass tube converting processes

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.