Factors that cause leakage of hot runner system (一)

    Today we talk about the leakage problem of hot runner system. There are many factors that may lead hot runners to leak.  We start from leakage of hot runner nozzle thread.


    A more representative case is from customer A(8drops hot runner system) and customer B(single nozzle), both are black PC materials. The hot runner nozzle  structure of customer A is the same as that of B. According to the analysis, the position where the nozzle is pressed against the core of the nozzle is only 0.9MM, and the suspension is 2.2MM. When we tighten the tip of the nozzle, the force is transmitted to the copper tip. Because the pressed place is too small and too much hanging, the copper tip is crushed down, and because the injection pressure is too large, the resin is forced to find the gap drill, and the result is from the collapsed place and then through the thread. Slowly seep out. Increase the 0.9 area to 1.4, and reduce the floating place to 0.5, still leaking. Later, we modified the structure of the hot nozzle slightly, using a steel-clad copper structure to seal the nozzle head and the body in both radial and axial directions. It is guaranteed that the resin will not slowly leak out from the screw. Only when the injection pressure is too large, and the strength of the body is not enough, the partial splitting of the body screw will lead to leakage.


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