1. Definition: the sprue is also known as inlet or inner runner.It is the narrow part between the shunt and the plastic parts, which is also known as the smallest part of the pouring system.
2. Effect: can make the distributary channel transmission velocity of molten plastic produce acceleration, forming an ideal flow, order, and quickly with cavity, but also plays the role of closed cavity to prevent the reverse liquid, and easy to make the sprue after molding and plastic parts.
3. Form of sprue.
The inside of the sprue
Common side sprue (edge sprue) :
The outer sprue
Fan-shaped sprue is used to form thin sheet plastic parts with larger width.
Flat sprue
Ear protectors.
Gap gate
General point sprue
Latent sprue (most of our company USES this method)
Ring sprue
Wheel sprue.
Claw sprue
Garden sprue
3>. sprue position selection.
(1) sprue selection has the nearest distance.
(2) the size and location of sprue should be avoided to produce spray and creep.
(3) the sprue should be opened at the thickest part of the plastic section.
(4) the selection of sprue position should make the plastic process the shortest and the material flow to the minimum.
(5) the gate position selection should be conducive to the expulsion of gas in the cavity.
(6) the selection of gate position should reduce or avoid the welding fastness of plastic parts.
(7) the selection of gate position should prevent the material flow from forming the shape of the cavity, the type of mold, and the extruding deformation.