CN-122008471-A - Double-injection molding system

Abstract

The invention discloses a double injection molding system, which is mainly characterized in that a material quantity control device is arranged between each injection device and a feeding device, the injection device is provided with an injection pipe provided with an injection port and a needle valve unit arranged in the injection pipe, the material quantity control device is provided with a control unit and a stop unit, the needle valve unit and the stop unit are respectively controlled by the control unit, after a screw of the feeding device mixes materials and supercritical fluid into a mixture, the stop unit and the needle valve unit are linked through the control unit so as to control the communication state between the feeding device and the injection pipe and the blocking degree of the injection port, thereby controlling the feeding quantity and the injection quantity of the mixture, avoiding the defect of incomplete filling caused by uneven discharge, and effectively improving the subsequent molding quality and yield.

Inventors

• HUANG FENGWU

Assignees

• 天岗精机科技股份有限公司

Dates

Publication Date

20260512

Application Date

20241111

Claims (3)

1. 1. A dual injection molding system comprises a feeding device, two injection devices respectively connected with the feeding device, and a clamping die device connected with a plurality of injection devices, wherein the feeding device is provided with a hopper for storing materials, a feeding pipe connected with the hopper, a feeding unit connected with the feeding pipe, and a screw rod arranged in the feeding pipe, each injection device is provided with an injection pipe, a feeding hole and an injection hole respectively arranged on the injection pipe, the clamping die device is provided with an upper die connected with the injection hole of each injection device, a lower die opposite to the upper die, a top die unit connected with the lower die, and a molding space enclosed when the upper die and the lower die are closed, and the dual injection molding system is characterized in that: The feeding unit is used for inputting a supercritical fluid to be used as a physical foaming agent, so that the supercritical fluid and the materials are mixed in the feeding pipe by the screw to form a mixture, in addition, each injection pipe is arranged in a straight line, a needle valve unit is arranged in the injection pipe, so that the injection amount of the mixture which is conveyed into the forming space in a straight line is controlled by the needle valve unit, a material amount control device is arranged between each injection device and the feeding device, and the material amount control device is provided with a control unit connected with the needle valve unit, and a stop unit which is linked by the control unit so as to control the feeding operation and the injection operation of the mixture.
2. 2. The dual injection molding system of claim 1, wherein each of said dose control devices has a metering unit coupled to said control unit.
3. 3. The dual injection molding system of claim 1, wherein the mold clamping device is connected to an air intake and exhaust device to maintain a constant pressure and stable foaming in the molding space.

Description

Double-injection molding system Technical Field The invention relates to an injection molding system, in particular to a double-injection molding system. Background The dual injection molding technology is a common and very mature technology, which can perform injection molding on two different materials into a single object, so as to produce plastic products with different colors, materials or textures, and can be used for injection molding of individual objects besides relatively complex products with more diversified functions, thereby improving the processing efficiency, reducing the processing procedures, saving the time and cost consumed by subsequent assembly, reducing the waste rate in the production process, and further improving the production efficiency and economic benefit. The existing double-injection molding system comprises two injection devices, a feeding device and a clamping die device, wherein the feeding device and the clamping die device are respectively connected with the injection devices, the feeding device is provided with a feeding pipe, a hopper and a feeding unit which are respectively connected with the feeding pipe, and a screw rod which is arranged in the feeding pipe, in addition, each injection device is provided with an injection pipe with a feeding hole and an injection hole, a pushing unit which is arranged in the injection pipe, in addition, the clamping die device is provided with an upper die and a lower die which are correspondingly arranged, and a top die unit which is connected with the lower die, the upper die is connected with the injection hole of each injection device, and when the top die unit pushes the lower die towards the upper die, the upper die and the lower die are mutually tightly closed to form a molding space. When the double injection molding system is used, firstly, the materials stored in the hopper are guided into the feeding pipe, meanwhile, a foaming agent is input into the feeding pipe through the feeding unit, in the process of rotating the screw rod, the materials and the foaming agent are fully mixed into a mixture, the mixture is pushed by the screw rod to enter the injection pipes of the injection devices, meanwhile, the top mold unit pushes the lower mold towards the upper mold, so that the upper mold and the lower mold are mutually closed to form the molding space, and then the mixture is extruded by the pushing unit to be injected into the molding space, so that an object is molded. However, after practical use, it is found that the screw has a plurality of threads on its surface to push the mixture to advance through rotation of the plurality of threads, so that the plurality of threads must continuously extend along the surface of the screw in a spiral inclined manner, so that the left and right sides of the same thread are not located at the same position as viewed from the end face, that is, the front and rear differences occur, and therefore, the feeding amount of the screw on the left and right sides is different, the feeding amount of the mixture on the front side is smaller than the feeding amount of the mixture on the rear side, so that the feeding amount of the mixture received by the plurality of injection devices is different, and uneven discharge, incomplete filling and other phenomena occur, thereby resulting in poor rate of subsequent injection molding. Disclosure of Invention Therefore, the present invention is directed to a dual injection molding system, which can precisely control the feeding and subsequent injection amount of a mixture, effectively avoid the defects of uneven discharge, incomplete filling, etc., and further improve the subsequent molding quality and yield. The invention comprises two independent injection devices, a feeding device connected with the injection devices, a clamping device connected with the injection devices, and a material quantity control device arranged between each injection device and the feeding device, wherein the feeding device is provided with a hopper for storing materials, a feeding unit for supplying supercritical fluid, a feeding pipe connected with the hopper and the feeding unit respectively, and a screw arranged in the feeding pipe, in addition, each injection device is provided with an injection pipe provided with a feeding hole and an injection outlet, and a needle valve unit capable of moving in the injection pipe, the injection pipe is arranged in a straight line, each material quantity control device is provided with a control unit and a stop unit, so that the materials and the supercritical fluid are uniformly mixed into a mixture after being rotated by the screw, the stop unit drives the stop unit in linkage by the control unit of each material quantity control device, so that the stop unit controls the mixture to be respectively guided into the plurality of injection pipes through the feeding pipe, and the mixture is enough to be injected by the injection pipe af