Laminar flow plays a big role in extruded tubing whether it’s used for balloons or not.  With balloon tubing, precise concentricity is critical to blowing quality parts and laminar flow is a dynamic in the extrusion process that also needs to be precisely uniform. Uniform flow of the polymer through the die and extrusion tip is adversely affected by a variety factors in the process such as uneven surface finish of the die and tip, a non-uniformly heated die and head, inconsistent backpressure, unevenly melted polymer and extrudate not drawn evenly from the die to the coolant. The angles used in the die and tip probably vary from one extruder to another. At MicroSpec and other extruders I know, that information is treated as proprietary knowledge.