Synventive Molding Solutions Two speeds are better than one for valve-gating system

Editor: Eric Culp

Two-speed sequential valve gating from Synventive Molding Solutions has been gaining in popularity and was introduced to Europe last year. It is said to offer a way to eliminate surface defects on large parts through better flow control.

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The hot runner technology helps eliminate surface irregularities in parts such as this back rest made for German sportscar company Audi.
The hot runner technology helps eliminate surface irregularities in parts such as this back rest made for German sportscar company Audi.
(Source: Synventive)

Syn-Flow two-speed sequential valve-gating hot runner technology, according to supplier Synventive, is a unique technology that provides moulders with optimised plastic flow control and solves common surface defect problems on large parts such as automotive bumpers and instrument panels.

Looking back at 15 years in the die and mould industry

Slowing down the valve pin to avoid a rush

The company said all of its Advanced Flow Control hot runner systems are designed to provide moulders with more control over the molding process to produce parts with higher quality surface finishes. Syn-Flow is a patent-pending, two-speed pin control technology for cascade or sequential valve-gated hot runner systems.

The initial opening speed of the valve pin is reduced to prevent an explosive rush of pressurized plastic. The valve pin then opens for the remainder of its stroke at maximum speed to appropriately fill the part.

Smoother filling results in smoother surfaces

This two-speed process is said to enable a smoother fill, which reduces hesitations and sharp velocity changes. This results in cleaner parts with excellent surface quality, and improved process efficiency, according to the company.

Mark Moss, executive vice-president at Synventive, claimed the system is “the only hot runner technology in the industry that allows moulders this level of control”. He explained the operational advantages: “It allows users to define the opening velocity of the valve pin, thereby regulating the flow of plastic into the mould at this critical stage, before the pin opens for full velocity and maximum plastic flow.”

The two-speed technology is claimed to be an industry first and can be used to eliminate surface defects on large molded parts. The supplier said the system can solve the following common defects:

  • Pressure alteration marks
  • Opposite direct gating marks
  • Sink marks after coating
  • Reduced adhesion of finishes.

The results for moulders are clean parts, reduced rejects, and better overall processing, the company said.

Each Syn-Flow system includes a hydraulic valve-gate hot runner system with 12mm, 16mm, or 22mm diameter nozzles and actuators with position sensors. Furthermore, the system has a Syn-Flow flow control package that contains control valves, signal lines for both valve control and position sensors and a control unit for up to 8 control zones.

Other solutions target different applications

The company also offers its Dynamic Feed system for hydraulic hot runners with a real-time, closed-loop process control at each gate in the mould. This is said to give the same level of control as separate injection units located at each hot runner nozzle in the mould. In the injection and pack pressure stages, the cavity filling is individually adjusted and controlled by intelligent software.

The electronically controlled E-Gate system can reportedly individually regulate up to 64 valves by controlling each pin’s position, speed, acceleration and stroke. It suits multi-shot/multi-material and sequential/cascading moulding applications that require premium cosmetic surfaces, the company said.