Synventive Molding Solutions, a unit of the Barnes Group, is developing controlled valve pin placement based on cavity sensor feedback in what is believed to be an industry first. A company spokesperson declined to comment on when the technology might be commercialized. A U.S. patent was issued Jan. 23.
Adjustments are carried out automatically by an algorithm executed by a controller receiving melt condition signals from sensors in the mold cavity.
In the Synventive invention, the simultaneous flow through each of multiple nozzles is made uniform by matching as closely as possible the rate of flow or profile of pin feedback that occurred in a test injection cycle.
For example, two sensors are used in the cavity of a 16-cavity mold. A sensor downstream of the gate is a temperature sensor with a user-defined trigger of 250F, with the upstream sensor (located near the entrance of the gate into the cavity) is a pressure sensor with a trigger of 5000 psi. The sensors provide input to a controller using data from the “perfect” test.
The invention addresses one of the key needs of markets such as automotive that require balanced fill for multi-cavity hot runner systems, which dramatically reduce waste and improve productivity.
Synventive describes itself as the leading global supplier of hot runner systems to the global automotive industry. It was founded in 1978 by Richard Devellian, Paul Swenson, Cam Stewart and Bob Eldridge in Gloucester, Massachusetts using technology developed for NASA. Synventive is now located in nearby Peabody.