household products gas assisted injection mold design rules
When designing, first consider which wall thickness needs to be hollowed out, which surface sink marks need to be eliminated, and then consider how to connect these parts to become air channels.
Large structural parts: Full thinning, partial thickening into airways.
The airway should be evenly distributed along the main material flow direction to the entire cavity, and closed-circuit airways should be avoided.
The cross-section of the airway should be close to a circle for smooth gas flow; the size of the cross-section of the airway should be appropriate; too small an airway can cause gas penetration; too large an airway can cause weld marks or cavitation.
The airway should extend to the final filling area (usually on the non-exterior surface) but does not need to extend to the edge of the cavity.
The main airway should be as simple as possible, the length of the branch airways should be as equal as possible, and the distal end of the branch airways can be gradually reduced to prevent gas acceleration.
The airway can be straight without bending (as little as possible bend), the corner radius of the airway should be larger.
For multi-cavity molds, each cavity must be supplied with a separate gas nozzle.
If possible, there is a second option for not advancing the gas.
The gas should be confined within the airway and penetrate into the end of the airway.
The exact size of the cavity is very important.
The symmetrical cooling of all parts of the product is very important.
With gated inlets, the balance of the flow is very important for uniform gas penetration.
The accurate amount of melt injection is very important. The error of each shot should not exceed 0.5%.