CN-115815425-B - Open internal extrusion forming die and large-size blind hole shell forming process

CN115815425BCN 115815425 BCN115815425 BCN 115815425BCN-115815425-B

Abstract

The invention provides an open internal extrusion forming die and a large-size blind hole shell forming process, which comprises a female die, a profiling punch and an extrusion punch, wherein an internal female die capable of transversely moving is arranged on the female die, a material ejection rod is arranged on the internal female die, a workpiece cavity with a variable shape is formed by a female die cavity and a cavity of the internal female die, a first cavity and a second cavity which are vertically arranged are arranged on the internal female die, the first cavity and the second cavity can be connected with the female die cavity, the process steps comprise that a pressing block is pulled upwards to enable the distance between two clamping plates to be larger than the outer diameter of a blank, the blank is fed from the top of the female die cavity, the profiling punch is controlled to move downwards until the blank is filled in a first workpiece cavity under the action of the profiling punch, the profiling punch is controlled to return, and the material ejection rod is controlled to move upwards until a convex edge at the top of a preformed piece is positioned above a clamping plate. The invention not only can smoothly and rapidly prepare the large-size blind hole shell, but also can obviously reduce the end allowance of the blank required in the forming process.

Inventors

LIN JUN
HUANG SHUHAI
WU TIANHAO
HU CHUANKAI
KANG FENG
WU YANG
CHEN QIANG
CHEN CHI

Assignees

中国兵器装备集团西南技术工程研究所

Dates

Publication Date: 20260505
Application Date: 20221211

Claims (6)

1. A large-size blind hole shell molding process adopting an open inner extrusion molding die is characterized in that, The open internal extrusion forming die comprises a die (5) and a pressing punch (2) matched with a die cavity (10), wherein an internal die (7) capable of transversely moving is arranged on the die (5) and positioned at the lower part of the die cavity (10), a jacking rod (8) is arranged on the internal die (7), a workpiece cavity with a variable shape is jointly formed by the die cavity (10) and the cavity of the internal die (7), a conical table (15) is arranged at the upper area of the die cavity (10), the diameter of the upper part of the conical table (15) is larger than the diameter of the lower part of the conical table (15), a first cavity (11) and a second cavity (12) which are vertically arranged are arranged on the internal die (7), both the first cavity (11) and the second cavity (12) can be connected with the die cavity (10), when the first cavity (11) is connected with the die cavity (10), a workpiece cavity is jointly formed by the upper area of the die cavity (10) and the first cavity (11), when the second cavity (12) is connected with the die cavity (10), at least two die cavity plates (1) are connected with the die cavity plates (1) at the top of each die cavity group (5), the two clamping plates (3) are rotationally connected to a mounting piece at the top of the female die (5), a supporting piece (4) is arranged at the top of the female die (5) and below the clamping plates (3), when the pressing block (1) is pulled upwards, the clamping plates (3) rotate clockwise, and the clamping plates (3) rotate to a limit position of clockwise rotation when in a horizontal state, the distance between the two clamping plates (3) in the horizontal state is smaller than the inner diameter of the female die cavity (10), and when the pressing block (1) is moved downwards, the clamping plates (3) rotate anticlockwise; the steps of the process include: Step 1, adjusting and fixing the position of an inner female die (7) to enable a first cavity (11) to be connected with a female die cavity (10); Step 2, pressing down the pressing block (1) to a proper position and fixing the pressing block so that the distance between the two clamping plates (3) is larger than the outer diameter of the blank; Step 3, feeding a blank from the top of a die cavity (10), controlling a profiling punch (2) to move downwards until the blank fills a workpiece cavity I under the action of the profiling punch (2), and obtaining a preformed piece (13) at the moment; Controlling the back stroke of the profiling punch (2), and controlling the material ejection rod (8) to move upwards until the convex edge (16) at the top of the preformed piece (13) is positioned above the material clamping plate (3); Step 5, controlling the pressing block (1) to move upwards until the material clamping plate (3) rotates anticlockwise to be in a horizontal state, and then controlling the material ejection rod (8) to reset, wherein at the moment, the convex edge (16) at the top of the preformed piece (13) is hung on the material clamping plate (3); Step 6, the position of the inner die (7) is adjusted again and fixed, so that the second cavity (12) is connected with the die cavity (10); step 7, executing step 2 again; step 8, controlling the extrusion punch (9) to move downwards until the blank fills the second workpiece cavity under the action of the extrusion punch (9), and obtaining a final formed part (14) at the moment; And 9, firstly controlling the material ejection rod (8) to move upwards, then taking out the final forming part (14), and finally cutting off the allowance of the bottom of the final forming part (14).
2. The process for forming a large-sized blind hole housing according to claim 1, wherein the diameter of the upper portion of the taper table (15) is 5-20mm larger than the diameter of the lower portion of the taper table (15).
3. The large-size blind hole shell molding process according to claim 1, wherein the upper diameter of the conical table (15) is 420mm, the lower diameter of the conical table (15) is 400mm, the distance between the two clamping plates (3) in the horizontal state is 398mm, the total length of the die cavity (10) is 2800 mm, the length of the upper area of the die cavity (10) is 2400mm, and the diameter of the upper area of the die cavity (10) is larger than the diameter of the lower area of the die cavity (10).
4. A large-size blind hole housing molding process according to claim 3, wherein the speed of the pressing punch (2) is controlled to be 5-20mm/s in the downward movement process, and the speed of the extruding punch (9) is controlled to be 20-40mm/s in the downward movement process.
5. The process for forming the large-size blind hole shell according to claim 1, wherein the inner die (7) is connected with a hydraulic pushing mechanism, a jacking mechanism or a screw transmission mechanism, and the hydraulic pushing mechanism, the jacking mechanism or the screw transmission mechanism is used for transversely pushing the inner die (7) to a target position.
6. The process for forming the large-size blind hole shell according to claim 1, wherein the inner concave die (7) is connected to a nut seat of a screw rod transmission mechanism, the inner concave die (7) is brought to a target position through horizontal movement of the nut seat, and a driving motor of the screw rod transmission mechanism adopts a servo motor.

Description

Open internal extrusion forming die and large-size blind hole shell forming process Technical Field The invention relates to the technical field of elastomer molding, in particular to an open internal extrusion molding die and a large-size blind hole shell molding process. The large-size blind hole shell refers to a formed part with an inner hole length-diameter ratio not smaller than 5 and an outer shape length-diameter ratio not smaller than 6. Background In the hot stamping technology of the elastomer, a molding process of performing extrusion molding under the action of a fixed die cavity to obtain a blind hole component is generally adopted. Because the extrusion punch used is slender, the extrusion punch is easy to be unstable under the action of vertical pressure, so that the aspect ratio of the inner hole of the blind hole shell obtained by fixing the die cavity is usually not more than 3, and the aspect ratio of the outer hole is usually not more than 4.5. More importantly, when the existing technology is adopted to form a large-size blind hole shell, the allowance of the end part is required to be enough for 200-300mm, and a large amount of excess materials are cut after the forming is finished. Obviously, this wastes very much molding material. Disclosure of Invention The invention aims to provide an open internal extrusion forming die and a large-size blind hole shell forming process, which can at least obviously reduce the end allowance of a blank required in the forming process. In order to achieve the above object, the present invention adopts the following technical scheme. The open inner extrusion forming die comprises a female die, a compression punch matched with a female die cavity, an extrusion punch, an inner female die, a jacking rod, a conical table and a first cavity and a second cavity, wherein the inner female die is arranged on the female die and positioned at the lower part of the female die cavity, the inner female die is provided with the transversely movable inner female die, the female die cavity and the cavity of the inner female die jointly form a workpiece cavity with a variable shape, the upper area of the female die cavity is provided with the conical table, the diameter of the upper part of the conical table is larger than that of the lower part of the conical table, the first cavity and the second cavity are vertically arranged on the inner female die, and the first cavity and the second cavity can be connected with the female die cavity. When the second cavity is connected with the female die cavity, the upper area of the female die cavity, the lower area of the female die cavity and the second cavity jointly form a second workpiece cavity. The pressing block is characterized in that the pressing block is arranged on the top of the female die, the lower end of each pressing block is hinged with a clamping plate, the two clamping plates are rotatably connected to a mounting piece on the top of the female die, a supporting piece is arranged below the clamping plates, when the pressing block is pulled upwards, the clamping plates rotate clockwise, the clamping plates rotate to the limit position of rotating clockwise when in a horizontal state, the distance between the two clamping plates in the horizontal state is smaller than the inner diameter of a cavity of the female die, and when the pressing block is moved downwards, the clamping plates rotate anticlockwise. By adopting the structure, the molding efficiency of molding the large-size blind hole shell can be greatly improved. Further, the inner female die is connected with a hydraulic pushing mechanism, a jacking mechanism or a screw transmission mechanism, and the hydraulic pushing mechanism, the jacking mechanism or the screw transmission mechanism is used for transversely pushing the inner female die to a target position. As a preferable scheme, the inner female die is connected to a nut seat of the screw rod transmission mechanism, the inner female die is brought to a target position through horizontal movement of the nut seat, and a driving motor of the screw rod transmission mechanism adopts a servo motor. By adopting the scheme, the workpiece can be smoothly molded, and the phenomenon of clamping and stopping in the extrusion process can be prevented. A large-size blind hole shell molding process adopting the open internal extrusion molding die comprises the following steps: step 1, adjusting and fixing the position of an inner female die, so that a first cavity is connected with a female die cavity; step 2, pressing down the pressing block to a proper position and fixing the pressing block so that the distance between the two clamping plates is larger than the outer diameter of the blank; Step 3, feeding a blank from the top of the die cavity, controlling the profiling punch to move downwards until the blank fills the first workpiece cavity under the action of the profiling punch, and obtaining a preformed