Design ring gate of injection mold is special of disk gate. It is used for cylindrical or round parts in a multi cavity mold or when a diaphragm gate is not practical. Melt materials enter the mold by by ring gate can improve weld line defect.
There are 2 main types of ring gate: inside and outside.
You can read all the content about gate design at here.
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1. Advantages and disadvantages of ring gate.
A. Advantages.
+ To prevent weld line of product.
+ Resin fill in molding cavity easily and have good quality.
+
B. Disadvantages.
+ Gate cutting is difficult.
+ Mold making is more expensive.
+ We lose many resins for a runner and gate.
2. How to design ring gate?
2.1. Dimension of ring gate with circular cross-section.
D: Thickness of feed runner. D=(s + 1.5) mm ~ (4/3 s + k) mm
L: Length of ring gate, L= 0.1~1.5 mm.
s: Thickness of cylindrical or round parts.
H: Thickness of ring gate, H= 2s/3 ~ 2 mm.
r= 0.2*s.
k = 2 mm for short flow lengths and thick sections.
k = 4 mm for long flow lengths and thick sections.
2.2. Dimension of internal ring gate.
D: Thickness of feed runner, D= s+1.5 mm
s: Thickness of cylindrical or round parts.
Length of gate: 0.5~1.5 mm. Width of gate 1~2 mm.
You can read runner design at https://mechanicalengblog.com/plastic-injection-molding-runner-system/
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