Crate and Crate Mold Plastic crate has been widely used in workshops instead of woody crate, it is used for storage and transport of various materials, components, semifinished or finished products, also used in the field of commodity circulation. Such as 24 bottles of beer crate, 12 bottles of beer crate, milk crate and large and small industry crate for workshops. As shown in below figure. These plastic crates have a large quantity demand and big dimensions, and have requires on mechanical property and weather-proof property. Highdensity polyethylene (PE-HD) has good fluidity and low cost, fine mechanical property and weather-proof property, can fully satisfy requires of plastic crate.
In the terms of plastic crate structure, in order to enhance the strength and rigidity, it usually designs crisscrossed Reinforcing outside the crate and bottom; in order to be convenient for pasting up and saving the label which mark the product name or trademark or the manufacturer, recessed blind holes are set outside the plastic crate; in order to be convenient for transportation and handling, it also sets portable through holes outside the crate. Therefore, there are bye holes and side concaves outside the crate, and blind holes or through holes outside the bottom.
Because of these bye holes and side concaves, so crate mold has side parting core pulling mechanism in structure, and single cavity injection mold with multi-gating is usually be used due to the large dimensions and long flow for plastic fondant. If using general runner injection system, it should be feed by pin gate and the mold structure should be 3-plate and double parting line mold. In order to remove condensate in the runner, eject system should be set. But it complicates the mold structure, so hot runner is widely used in the crate mold.
Crate mold with hot runner shows at left. Materials in sprue, runner and gate keep molten by heating. In the process of injection and holding, the runner is unimpeded, and plastic fondant get into cavity under the holding pressure and fill the mold. Because of unimpeded runner, there requires much less injection pressure and holding pressure than general runner injection molding and more materials when packing feeding, the plastic crate is close-grained and has a good quality. In cooling process, materials keep molten in sprue, runner and gate, but cool and curdle in the cavity. (edit by email@example.com ) 1