Case Study Cavity-to-cavity consistency

Author / Editor: Reinhard Kabus / Rosemarie Stahl

US-based Phillips Plastics,a leading injection molding company, requested Incoe Corporation and Beaumont Technologies to assist them in their continual commitment for a 0% PPM reject production goal.

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Melt-Flipper reduces flow imbalence caused my material shear.
Melt-Flipper reduces flow imbalence caused my material shear.
(Source: Incoe)

To achieve the next level of improvement Phillips chose Incoe to manufacture a hot runner system utilizing the Melt-Flipper technology from Beaumont Technologies for the production of a medical device cover using a pc/abs material.

Incoe, which started out in 1958 as Injection Control Engineering, designs and manufactures hot runner systems driven by performance for the processing of all injection moldable plastic materials.

Phillips recognises, that filling inconsistencies caused by shearing of the material during injection molding leads to a poor part quality. The eight drop hot runner system was required to produce less than 5% part weight deviation on a 95% filled part molding pc/abs.

Short shot part weight differences also cause longer start-ups due to the continual “tweaking” of nozzle temperatures until a stable process is established. This process, and the lengthy time period were virtually eliminated.

The Incoe system delivered an average of 0.375% imbalance for all eight cavities at the 95% fill condition. Other than “steel variations” which are inconsistencies in machining that can be identified and corrected; shear induced imbalances have been the root cause for filling imbalances in both cold and hot runner systems but remained a mystery until John Beaumont of Beaumont Technologies discovered the phenomenon and created a method to compensate for the effect.

Also included in the Phillips evaluation of this hot runner system was a deliberate 6 degree Celsius change in the melt temperature setpoint. Still no filling imbalances were detected further demonstrating the robustness of the technology.