Independent Zone Control for Uniform Heating
The Blockwise Model FF Balloon Former has achieved a new level of mold temperature uniformity and repeatability in the balloon forming process with the implementation of independent control of each heating zone. Each stack in the induction heating module measures the temperature and controls its heat output.
The heating power of each stack is modulated by an independent controller that communicates and coordinates with the other stack controllers. All these controllers communicate with the main heater controller, which sets the total power to send to the entire induction module. Each stack in an induction module is outfitted with two precision temperature sensors for redundant measurement.
While other systems measure the surrounding heating jacket, the Blockwise sensors are designed to measure the mold directly, resulting in an accurate, repeatable, and real-time temperature measurement.
Axial Uniformity
To test the uniformity of the mold temperature, four thermocouples were placed inside a mold at separate locations along the length. Measurements were taken at each location to plot the overall internal temperature profile of the mold.
This test confirms that the Blockwise system yields impressive levels of temperature uniformity. The following graph shows a test of a 397mm long mold with a 20mm outer diameter. After reaching the temperature setpoint, the temperature spread (ΔT) is uniform within 2°C across the measured points. It achieves this uniformity nearly instantaneously after reaching the setpoint temperature.
Circumferential Uniformity
Mold circumferential temperature distribution is extremely uniform on the FF balloon former. The architecture of Blockwise’s induction heating system produces heat by inducing eddy currents that circle around the mold. These circling currents, combined with the mold geometry, produce near perfect temperature uniformity.
To show circumferential temperature uniformity, thermocouples were inserted at consistent depths inside a mold at 12:00, 3:00, 6:00, and 9:00 positions. Measurements were taken at each location to plot the temperature uniformity around the mold.
The following graph shows a test of a 77mm long mold with a 20mm outer diameter. The temperature spread (ΔT) is less than 0.5°C during steady state, with a max spread of ~1°C during transient.
Temperature uniformity across the balloon forming mold is critical to producing quality balloons with ideal properties such as consistent wall thickness, compliance, and straightness. Blockwise’s induction heating system with independent zone control sets a new standard for rapid heating and uniform temperature.
Blockwise is dedicated to delivering the highest quality manufacturing equipment available. We offer attentive service and reasonable prices. Please contact the factory for additional info, or to start working on your project today.
