Macro Engineering introduces an updated design for its most sophisticated member of the D10 air ring family, the D10 PRO Automatic Air Ring. The D10 PRO dual lip air ring was developed for use with an advanced thickness control system that incorporates intelligent control software, a thickness sensor on an oscillating ring and a touch screen interface.
Based on Macro’s signature D10 dual lip air ring, the patented design of the D10 PRO guarantees excellent gauge control without negatively affecting bubble stability and cooling performance.
The initial setup of the air ratio between the primary and secondary lips is simple and done in the same way as the conventional D10 dual lip air ring. This feature makes the patented design of the D10 PRO air ring stand out from other designs for its simplicity and operational efficiency. No additional blower or compressed air is needed, no excess air is blown away, and no heating of previously cooled air is required.
The air for the primary lip is taken directly from the mixing chamber and split into independent vanes that extend from the chamber directly to the exit of the primary lip. Thickness correction is achieved by precisely adjusting the airflow on each of the vanes using a valve activated by a stepper motor. The air flow through the vanes is laminar, preventing any significant mixing of the air streams as they exit the primary lip. This feature assures precise localized thickness corrections.
Altering the volume of air flow through the vanes has two effects on the bubble: Firstly, a change in the air flow acts to change how quickly the film is cooled, which in turn affects it’s thickness. Secondly, and more importantly, the change in air flow influences the geometry of the bubble. By reducing the volume of air, the melt is drawn out over the deflector lip thereby stretching the film and thinning the gauge. Conversely, when the air volume is increased, the melt is forced away from the deflector lip, thus preventing it from being drawn out and thinned.
These changes in bubble shape are minute - they cannot be perceived by observing the bubble yet they have a significant effect on the film gauge. The end result is a rounder bubble due to the improved gauge uniformity.
In Europe, Macro Engineering has teamed up with DOTECO s.r.l. (Italy) to market the control system under the name PROFIX, Air Ring with Integrated Auto Profile Control.