How To Deal With The Expansion Of Hot Runner System Parts?
Assuming that the value of A in the plan is much smaller than the lateral thermal expansion of the runner plate, the anti-rotation pin will block the lateral elongation of the runner plate after being heated, forming the warping deformation of the warm runner plate, causing the sealing between the warm runner plate and the nozzle to fail and causing The melt leaks. The axial thermal expansion of the support ring 3, the runner plate 4, and the gate nozzle 5 will eliminate the cold void C. Assuming that the cold space is too large, the axial thermal expansion is much short, and then the lateral thermal expansion of the warm runner plate is restrained, and the melt leakage occurs between the nozzle and the warm runner plate. Therefore, when planning the mold, correctly calculate the thermal expansion of the system, leaving a reasonable thermal expansion space is a condition to avoid melt leakage. The thermal expansion of the parts of the warm runner system causes the relative orientation changes between the mold parts of the equipment at room temperature. In order to compensate for the thermal expansion of the parts, it is necessary to leave a suitable expansion space. The warm runner plate is fixed on the fixed template 8 through the middle positioning pin 2 and stretches adjacently after being heated.
The lateral thermal expansion of the warm runner plate will reduce the space A between the runner plate and the positioning pin 7, and the melt pressure during injection will cause the nozzle 5 and the warm runner plate 4 to cause melt leakage. Assuming that the cold space is too small and the thermal expansion pressure of the system is too large, the system parts will be tortuous. Perhaps the compressive stress exceeds the yield stress of the fixed template parts, and the support ring crushes the fixed template.
