Hot runners clear the way for transparent part production

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The company said it has improved the thermal control of nozzles with special brass sleeve heaters. Each heater is dedicated to the thermal control of the gate zone, a step said to ensure more precise and steady process control. The high thermal conductivity of brass also helps standardise the thermal profile, the company noted.

These technical solutions are said to provide a more constant temperature, with a tolerance in the region of 10 C across the entire system. Users receive thermal analysis of the manifolds for each system to demonstrate that temperature uniformity is reliable.

The nozzle is protected by a stainless steel tube that ensures consistent temperature distribution by reducing thermal dissipation. The tube also protects the thermocouple wires. The nozzle design has been modified to minimise cut-out pocket space in the injection area.

All internal hot runner channels have been engineered to avoid stagnation spots that could cause unacceptable defects in crystal clear lenses, the supplier explained. Special shaped plugs have also been installed to further avoid any stagnation close to the valve gate pin.

Attention to detail provides prowess

Tip and end ring geometries, and the material used to produce them, have been selected to optimise gate area temperature, the supplier noted. Special attention has also been paid to the quality of the injection points in the moulded part. Furthermore, the units have been designed to provide optimal performance even for high injection pressure, according to the manufacturer.

The supplier added that the entire hot runner is made of a special steel and coating which prevents polycarbonate degradation and, as a result, the risk of unaesthetic black spots on crystal clear applications such as lenses and window panels. The result is fewer rejects and higher productivity, the company said.