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Design specification for exhaust groove of die-casting mold, including section, direction, sealing, and back pressure control

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  • Release time: 2026-11-07

Design specification for exhaust groove of die-casting mold, including section, direction, sealing, and back pressure control
The exhaust groove is a channel for discharging the air in the mold cavity and the decomposition gas of the mold release agent. Many mold exhaust grooves are made narrow and shallow, which can be blocked as soon as they are hit, making them virtually useless.
1、 Reference for basic parameters of exhaust groove
Aluminum alloy high-pressure die-casting, exhaust groove depth of 0.08-0.15mm; width distributed according to the total amount of gas, the exhaust after overflow at the end can be widened; The depth cannot exceed the gap between the alloy flash edges, otherwise the aluminum will run directly. The depth is too large, and the parting surface continues to flash.
2、 Principles of exhaust layout
Arrange at the end of the material flow, the confluence of two streams of material, and the dead corner of gas retention; Priority should be given to leading out from behind the overflow channel, and not directly facing the molding surface of the cavity; The exhaust direction should be as straight as possible, with fewer sharp turns to reduce gas resistance. The end of the alloy wheel mount and the sealing position of the wheel rim are the key areas for exhaust.
3、 The hazards of exhaust back pressure
Poor exhaust, insufficient cross-section, blockage, increased back pressure inside the mold cavity, increased resistance to aluminum liquid filling, and batch explosion of rolled air holes; The back pressure is too high, the rapid injection pressure rises abnormally, and the injection curve shows a peak.
4、 Reasons and countermeasures for easy blockage of exhaust ducts
ADC12 has a lot of silicon slag and small silicon particles stuck in the exhaust gap; Countermeasure: Pre trap slag in the overflow tank and regularly clean the exhaust; Expand the exhaust rear end into an exhaust chamber to reduce flow rate and minimize silicon slag jamming.
5、 Taboos on exhaust
The exhaust groove cannot lead to the mold cooling water circuit; Cannot leak air with the top needle hole; Cannot open the exhaust on the main surface of the appearance; Do not gather multiple exhausts at the same narrow outlet as it may interfere with each other. The depth of the low pressure casting exhaust groove can be slightly larger, the filling speed is low, and it is not easy to run aluminum. Google's "die casting vent design specification" is aimed at mold engineers.
FAQ
Is the deeper the exhaust, the better the exhaust effect?
Exceeding the gap between the alloy flash edges, directly running aluminum, and losing control of the parting surface flash edges.
How often is the exhaust duct cleaned?
ADC12 has a lot of silicon slag, and several hundred molds need to be inspected; A356 is relatively clean.
Can the exhaust duct cross the mold frame?
Try to be as short as possible, as the cross mold frame is prone to misalignment and aluminum leakage.
Can the gap between the top pins be used as exhaust?
Auxiliary exhaust, unstable, cannot be used as the main exhaust.
What is the use of enlarging the cavity at the back of the exhaust groove?
Slow down, reduce the probability of silicon slag rushing into the gap, and minimize blockage.
6. If there is no exhaust at the air vent position, can we add exhaust directly?
Prioritize whether it is the end of the material flow, rather than the limited effect of adding exhaust at the end.
7. Can the mirror surface be equipped with exhaust?
Avoid side A and place it on the non visible edge.
8. Should the exhaust groove be polished very smoothly?
Moderately rough, conducive to gas flow, too smooth is prone to sticking aluminum and blocking grooves.

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