Film gate as shown in figure 6-19, also known as flash gate, thin film gate like circular runner, but used in flat edges of plastic parts, it has a flat gate, the gate width can jumper the whole or part of the cavity cavity edge. Film gate is suitable for pressing LiSu pieces, and often used in large, flat plastic parts
Film gate F as shown in figure 6-19, also known as flash gate (flash gate), thin film gate like circular runner, but used in flat edges of plastic parts, it has a flat gate, the gate width can jumper the whole or part of the cavity cavity edge. Film gate is suitable for pressing LiSu pieces, and often used in large, flat plastic parts, in order to keep the minimum of the warp. Film gate size is small, the thickness is about 0.25 ~ 0.63 mm, width is about 0.63 mm
Automatic removal of gate Automatic removal of gate and mold actions, during ejection plastic parts cut gate. They are applied to: y avoid removing gate secondary processing. Y to maintain uniformity of cycle time
Y minimize gate marks. Automatic removal of gate includes the following types: needle gate, the latent type gate and hot runner gate, and the valve gate.
(1) needle gate Pin gate (pin gate) as shown in figure 6-20, usually applied to three board mould, the runner system located in a component model online templates, cavity plastic parts meet the main parting line. The gate with a back taper Angle direction parallel to the template through the middle template. When open cavity of main parting line, the small diameter end of the needle gate from plastics tore off, then open the port can be parting line out port waste. This system can also open port parting line first, then using assistive devices off port waste. Needle gate used most often in a single plastic parts more into the water, in order to ensure symmetrical filling, or shorten the length of flow channel in order to ensure the parts of the holding operation. The typical needle gate 0.25 ~ 1.6 mm in diameter.
(2) submarine gate the latent type gate Latent type gate (submarine gate) or is called the tunnel gate (tunnel gate), chisel gate (chisel gate), as shown in figure 6-21, used in the two plate mold, below the parting line, the end of the passage between the cavity and processing a tilt the cone of the tunnel. Ejection parts and runner, gate will be separated from the plastic parts. Typical latent type gate is 0.25 ~ 2.0 mm in diameter, runner from coarse to fine, until become globular endpoint. If parts of the functional area has the characteristics of large diameter of the needle, it can be connected to the latent type gate, to reduce processing costs. If the needle features occur in the hidden surface, also can not remove him. To multiple submerged in cylinder inside the gate design, can replace the disk gate, and have the function that automatically remove the gate, to the periphery of the molded parts roundness than disk gate parts of roundness is poor, but also can also accept it.
(3) hot runne the hot runner gate The hot runner gate (Hot - runner gate) or is called thermal probe gate (hot - the probe gate), as shown in figure6-22, usually from electrothermal vertical sprue and heat flow transmitted directly melt into the cavity, to produce plastic parts without a runner. Control the pressure maintaining cycle in plastic parts near the gate of solidification. When the template is opened, a fairly high temperature plastic tear from the cavity.
(4) Valve gate valve type gate valve type gate (Valve gate) as shown in figure 6-23
, in the hot runner gate increase a needle bar, in order to close the gate before gate solidification.
It can be applied in larger gate without gate trace. Because of the holding period is controlled by needle bar, valve type gate can get better the holding period and the stable quality of plastic parts.