Tunnel Gate Injection Molding

If a material is too flexible a proper shearing action isn t achievable.

Tunnel gate injection molding.

Assuming you haven t. These gates tunnel under the tool steel into a wall section. If the injection molding requirements meet the smaller the number of gates are the better it is it would reduce the weld marks. Clearly when designing for injection molding gate selection may require some deliberation.

Effectively it was a tunnel gate jumping into another tunnel gate. Tunnel gates also get a bad reputation for leaving a high gate vestige especially when the size of the gate is large. Compatible materials for tunnel gates. The final part as seen at right shows the post from the pin or tunnel gate that was removed in a manual process.

Injection molding gate types edge gates. From there the material would flow up the tunnel gate and into a short cold runner with an edge gate feeding the top inside edge of the gauge cutout. As the part ejects the tunnel gate is sheared off as the ejector pin pushes up on the runner causing the gate to rip at the opening of the gate orifice. Tunnel gate diameters vary from 0 5 0 8 mm for unreinforced plastics to larger diameters of 2 mm plus for reinforced materials.

Plastic molding tutorial 112 varieties of tunnel gates. Pin gates are sometimes called post or tunnel gates and are commonly used on gears as shown here at left. The tunnel gate submarine gate is used very frequently as a type of gate having a structure that automatically cuts the molded item and gate at the time of opening and closing the parting surface. That s because a tunnel gate relies on the ability of the material to shear on the tunnel gate edge as the part is ejected.

Tunnel gates can t be used with every material available for injection molding. The tunnel gate could then feed into another tunnel gate coming in from the opposite direction.