CN220562236U - Auxiliary tool for spiral extrusion forming die - Google Patents

Abstract

The utility model discloses an auxiliary tool for a screw extrusion forming die, which comprises a positioning ring fixed at the joint of a front cone and a rear cone of an inner cavity of the die, a center baffle ring arranged at the inner side of the positioning ring, and a connecting rib for connecting the positioning ring and the center baffle ring; the outside of center keep off the ring is the axial both ends with the face flush face of retainer both ends, the inboard of center keeps off the ring is the round platform shape through-hole that the front end is little, the rear end is big, the taper ratio of round platform shape through-hole is 1:22 ~ 1:11, the length of round platform shape through-hole is 1.5 ~ 2 times of face of cylinder length, the both ends of round platform shape through-hole with the both ends of face of cylinder are connected through the conical surface respectively, and the tapering of rear side conical surface is greater than the tapering of front side conical surface. The auxiliary tool improves the consistency of the molding quality of the large-diameter solid propellant grains.

Description

Auxiliary tool for spiral extrusion forming die

Technical Field

The utility model relates to an auxiliary tool for a screw extrusion forming die, and belongs to the field of die design.

Background

Screw extrusion forming is one of the important forming processes of solid propellant at home and abroad at present. The structure of the screw extruder mainly comprises a screw, a machine barrel and a die, wherein in the screw extrusion molding process, after the medicine is added into the screw extruder from a hopper, the medicine is snapped by the threads of the rotating screw to forcedly push the medicine to the machine head direction, and then the medicine is extruded into medicine grains with certain density and preset size through the die. The forming die is taken as an important component of the screw extrusion equipment and plays a vital role in forming the solid propellant. The traditional screw forming die is composed of a front cone, a rear cone and a forming body which are sequentially connected from back to front; in order to improve the molding quality of large-diameter solid grains, a mold needle and a needle frame for fixing the mold needle are arranged in a mold cavity; when the medicine is pressed, the medicine in the inner cavity of the front cone of the mould flows into the rear cone through the needle frame, and is axially cut and split into a plurality of strands by the connecting ribs of the needle frame and then enters the rear cone of the mould, the flowing speed of the medicine is gradually accelerated due to the gradual diameter reduction of the rear cone, the speed of each strand of medicine in the same section is higher than that of the mould wall, and when the medicine flows into the forming body, the speed gradient is obviously increased due to the inlet effect, the flowing speed of each strand of medicine is difficult to control, the forming quality consistency of the solid medicine column after extrusion forming is easy to be poor, and the product quality is difficult to ensure.

Disclosure of Invention

The utility model aims to solve the problem that the consistency of molding quality is poor when a traditional screw extrusion molding die is used for pressing a large-diameter solid propellant product, and provides an auxiliary tool for the screw extrusion molding die.

The utility model aims at realizing the following technical scheme:

the utility model relates to an auxiliary tool for a screw extrusion forming die, which comprises a positioning ring fixed at the joint of a front cone and a rear cone of an inner cavity of the die, a center baffle ring arranged at the inner side of the positioning ring, and a connecting rib for connecting the positioning ring and the center baffle ring;

the outside of center keep off the ring is the axial both ends with the face flush face of retainer both ends, the inboard of center keeps off the ring is the round platform shape through-hole that the front end is little, the rear end is big, the taper ratio of round platform shape through-hole is 1:22 ~ 1:11, the length of round platform shape through-hole is 1.5 ~ 2 times of face of cylinder length, the both ends of round platform shape through-hole with the both ends of face of cylinder are connected through the conical surface respectively, and the tapering of rear side conical surface is greater than the tapering of front side conical surface.

Advantageous effects

According to the auxiliary tool disclosed by the utility model, through the design of the central conical hole, the flow speed gradient of the medicine in the rear cone is reduced, the flow speed of each medicine is balanced, and the consistency of the molding quality of the large-diameter solid propellant grains is improved, so that the molding quality of a product is improved.

Drawings

FIG. 1 is a schematic structural view of an auxiliary tool of the present utility model;

FIG. 2 is a cross-sectional view taken along A-A of FIG. 1;

in the figure, a 1-positioning ring, a 2-center baffle ring and 3-connecting ribs.

Detailed Description

The present utility model will be further described with reference to the drawings and examples.

Examples

As shown in FIG. 1, the auxiliary tool for the screw extrusion forming die comprises a positioning ring 1 fixed at the joint of a front cone and a rear cone of an inner cavity of the die, a center baffle ring 2 arranged at the inner side of the positioning ring 1, and a connecting rib 3 for connecting the positioning ring 1 and the center baffle ring 2;

as shown in fig. 2, the outer side of the center baffle ring 2 is a cylindrical surface with two axial ends flush with the end surfaces of the two ends of the positioning ring 1, the inner side of the center baffle ring 2 is a circular truncated cone-shaped through hole with a small front end and a large rear end, the taper ratio of the circular truncated cone-shaped through hole is 1:22-1:11, the length of the circular truncated cone-shaped through hole is 1.5-2 times of the length of the cylindrical surface, the two ends of the circular truncated cone-shaped through hole are respectively connected with the two ends of the cylindrical surface through conical surfaces, and the taper of the rear conical surface is larger than that of the front conical surface;

taking a solid grain with the outer diameter phi of 100mm as an example, a mould provided with the auxiliary tool of the embodiment and a mould provided with a conventional mould needle are adopted for pressing respectively.

Adopting a die provided with the auxiliary tool of the embodiment, wherein the density of the molded grain is 1.69g/cm close to the center ³ Near the outer wall 1.69g/cm ³ . The compressive strength at normal temperature is 30MPa.

The density of the formed grain is 1.67g/cm near the center by adopting a conventional mould with a mould needle ³ 1.68g/cm near the outer wall ³ . The compressive strength at normal temperature is 22MPa.

From the experimental test results: when the mould provided with the auxiliary tool is used for preparing the solid grain, the grain has good compactness and excellent comprehensive performance, and the quality consistency of the center position and the outer wall position of the grain is obviously improved.

Claims (1)

1. An auxiliary fixture for a screw extrusion forming die is characterized in that: the device comprises a positioning ring fixed at the joint of a front cone and a rear cone of an inner cavity of a die, a center baffle ring arranged at the inner side of the positioning ring, and connecting ribs for connecting the positioning ring and the center baffle ring;

the outside of center keep off the ring is the axial both ends with the face flush face of retainer both ends, the inboard of center keeps off the ring is the round platform shape through-hole that the front end is little, the rear end is big, the taper ratio of round platform shape through-hole is 1:22 ~ 1:11, the length of round platform shape through-hole is 1.5 ~ 2 times of face of cylinder length, the both ends of round platform shape through-hole with the both ends of face of cylinder are connected through the conical surface respectively, and the tapering of rear side conical surface is greater than the tapering of front side conical surface.