FlowControl
Valve Gate and Cavity Pressure Sensor Technologies
FlowControl and PressureSense technology offer material savings and process control beyond the capabilities of a standard cold runner. This technology provides waste reductions, scrap elimination, improved automation, and management, giving customer production an advantage. The strong links between the FlowControl cold runner, PressureSense system, and DRC2030 TMB controls mean optimal results can be achieved even when molding very challenging elastomer articles.
Traditionally, the most common CRB system is a solid, drilled block with open, cooled nozzles. To improve the process control, the standard nozzle towers are replaced with a specially designed tower that is hydraulically or electrically controlled to open and close. Towers may be sequenced independently of one and other from the DESMA machine control panel. This is a FlowControl cold runner.
The ability to start and stop the material flow into a mold opens up many processing advantages including:
- The ability to produce articles of differing geometries with a family mold
- Increased flexibility with gate locations because a naturally balanced manifold is no longer required
- Elimination of engineered waste thanks to direct injection without runners
- Simplified tooling designs
PressureSense technology ensures repeatable optimal mold filing accuracy
DESMA Engineering is a leader in pressure sensor technology for elastomer injection molding. Our team has experience with the integration of cavity pressure sensors in our mold and CRB systems, which, in conjunction with our DRC control system, ensure optimal mold filling.
The next level of technology from a FlowControl cold runner is the integration of pressure sensors directly in the mold cavity. These sensors read the actual internal cavity pressure generated by the material. DESMA has developed software within the machine control that will interpret actual cavity pressure readings and close the FlowControl needles based on those readings – we term this PressureSense. PressureSense requires the tool to be fitted with pressure sensors to provide an actual internal cavity pressure reading back to the machine control. The Process Engineer determines a set pressure value for each cavity through injection trials. Once this pressure value is established the machine will close FlowControl needles when the pressure setting is achieved. The advantage of this system is that it is closed loop and takes much of the process variation seen in daily production out of the equation because the injection process is governed by the actual cavity pressure.