Type 1: Open nozzle for direct gating
- Open nozzle without plastic insulating cap
Not very common for processing TPU, because of poor thermal separation, resulting in "shiners", haloing, sticking and material drooling. (Fig. 8)
-Open nozzle with plastic insulating cap
The insulating cap and cooling system lead to better thermal separation (Fig. 9).
-Open nozzle with torpedo
The narrow annular slit leads to excessive shear. Normally unsuitable for TPU (Fig. 10).
Type 2: Open nozzle with sprue
This system is used primarily for large molds
Type 3: Nozzle with needle valve
A clean gating point can be placed directly on
The flow behavior of Desmopan® and Texin™ is
basically the same as that of other thermoplastics. The length of
the flow path is dependent on the melt temperature, the wall
thickness of the part to be filled, the injection speed and the
rheological properties of the material.