CN116061399A - Hot nozzle assembly of hot runner system - Google Patents

Abstract

The invention provides a hot nozzle assembly of a hot runner system, and belongs to the technical field of injection molds. It solves the problem of poor product quality caused by uneven temperature of melt plastics. The device comprises a long tubular body, a sprue bush fixedly connected to one end of the body and a shunt nozzle core fixed between the sprue bush and the sprue bush, wherein an inlet cavity is formed in one end of the shunt nozzle core, which is far away from the sprue bush, a convex part is arranged in the inlet cavity, a plurality of shunt holes distributed around the convex part are formed in the shunt nozzle core, the shunt nozzle core at the inlet cavity comprises an accelerating section and a retaining section in sequence along the axial direction, the wall of the inlet cavity at the accelerating section is provided with a taper, the maximum inner diameter of the inlet cavity at the accelerating section is the same as the inner diameter of the body, the minimum inner diameter of the inlet cavity at the accelerating section is the same as the inner diameter of the inlet cavity at the retaining section, the convex part is positioned in the inlet cavity at the retaining section and the top of the inlet cavity is provided with a flow disturbing surface, and the cross section of the shunt hole is approximately polygonal. It has the advantages of more uniform temperature of the melt plastic, good product quality, etc.

Description

Hot nozzle assembly of hot runner system

Technical Field

The invention belongs to the technical field of injection molds, relates to a hot runner system, and particularly relates to a hot nozzle assembly of the hot runner system.

Background

At present, an injection mold commonly adopted in the injection molding industry is a hot runner injection mold, and compared with a common mold, the quality of a plastic product injected by a hot runner system is higher. The hot runner system is characterized in that the plastic of a runner and a sprue is kept in a molten state by a heating method, the hot runner system generally comprises a hot nozzle assembly, a flow dividing plate, a temperature control box and other corresponding accessories, and the existing hot runner system is specifically divided into an open hot runner system and a needle valve type hot runner system according to requirements. The open type hot runner system refers to that an outlet of the hot nozzle assembly is normally open, the conventional normally open type hot nozzle assembly generally comprises a tubular body and a sprue bush fixed at one end of the body, the other end of the body is fixedly connected at a split opening of a split plate (the split opening is communicated with a main runner in the split plate), and a sprue is abutted against a cavity of a die. Furthermore, in order to ensure that the melt plastic is not blocked in the pouring gate, a flow dividing nozzle core is generally fixed between the body and the pouring gate sleeve, and a plurality of flow dividing holes are formed in the flow dividing nozzle core, so that the melt plastic is firstly divided by the flow dividing nozzle core and then injected into a cavity of the die.

In the above, it is mentioned that the molten plastic is kept in a molten state in the hot runner system by heating, and as an example, the molten plastic is in a hot nozzle assembly, heat transfer is generally adopted, that is, a heating ring or a winding heating wire is arranged outside the body, and after the heating ring or the heating wire is electrified to generate heat, the heat is transferred to the molten plastic through the body. However, in practice, the temperature of the molten plastic against the inner wall of the body must be higher than the temperature of the molten plastic at the rest of the positions, and the molten plastic at the different positions is mixed only to a small extent when entering each of the distribution holes, so that the temperature of the molten plastic injected into the cavity of the mold is uneven, resulting in poor quality of the produced product.

Disclosure of Invention

The invention aims to solve the problems in the prior art, and provides a hot nozzle assembly of a hot runner system, which solves the problem of poor product quality caused by uneven temperature of melt plastics.

The aim of the invention can be achieved by the following technical scheme:

the hot runner system's hot runner subassembly, including long tubular body, fixed connection in the runner cover of body one end and fix the reposition of redundant personnel mouth core between the two, the one end that the runner core kept away from the runner cover is equipped with the oral cavity and the reposition of redundant personnel mouth core has the bulge in the oral cavity, the reposition of redundant personnel mouth core is equipped with a plurality of reposition of redundant personnel holes that distribute around the bulge, its characterized in that, the oral cavity department reposition of redundant personnel mouth core of import department in proper order along the axial including accelerating section and holding section, the oral cavity chamber wall of accelerating section department has the tapering, the biggest internal diameter of the oral cavity of accelerating section department is the same with the oral cavity internal diameter of holding section department and its minimum internal diameter is the same, the cross section of reposition of redundant personnel hole is the polygon approximately in the oral cavity of holding section department and its top, the bulge has the external appearance, the tapering flow surface is circular plane, the centre of a circle of disturbance surface and the central axis of body is collinearly.

The molten plastic flows from the main flow channel of the hot runner system into the body and along the body. The flow dividing nozzle core at the inlet cavity sequentially comprises an accelerating section and a holding section along the axial direction of the flow dividing nozzle core, the wall of the inlet cavity at the accelerating section is provided with a taper, the maximum inner diameter of the inlet cavity at the accelerating section is the same as the inner diameter of the body, the minimum inner diameter of the inlet cavity at the accelerating section is the same as the inner diameter of the inlet cavity at the holding section, and the through-flow sectional area at the maximum inner diameter of the inlet cavity at the accelerating section is larger than the through-flow sectional area at the minimum inner diameter of the inlet cavity at the accelerating section, so that melt plastic can enter the holding section at a larger flow velocity after passing through the accelerating section. Meanwhile, the protruding part is positioned in the inlet cavity at the retaining section, the top of the protruding part is provided with a flow disturbing surface, a part of the accelerated melt plastic directly impacts on the flow disturbing surface after entering the retaining section, the accelerated melt plastic has larger kinetic energy, so that the accelerated melt plastic can be sputtered widely around and impact other melt plastics after impacting on the flow disturbing surface, and the flow disturbing surface is perpendicular to the central axis of the body, the center of the flow disturbing surface is collinear with the central axis of the body, so that the melt plastic farthest from the inner wall of the body (farthest from the inner wall of the body, the temperature is correspondingly lowest) can be impacted on the flow disturbing surface more and sputtered around to be fully mixed with the melt plastic with higher temperature, and the flow of the melt plastic is disturbed to a certain extent and is similar to a stirred state, so that the melt plastic can be mixed once before being shunted by each shunt hole. After that, the molten plastic enters into each flow dividing hole, the cross section of the flow dividing hole is approximately polygonal (the cross section refers to the cross section along the direction vertical to the center line of the flow dividing hole), and when the molten plastic passes through the flow dividing hole, each inner side wall of the flow dividing hole forms resistance to the corrugation of the molten plastic which expands outwards along the radial direction and thereby generates a reaction force to the molten plastic, so that the action of turbulent stirring, namely secondary mixing, is formed for the molten plastic in the flow dividing hole. By combining the two mixing steps, the temperature of the melt plastic entering the mold is more uniform, and the quality of the product is improved.

Conventionally, for the purpose of enabling the melt plastics to be thoroughly mixed before being split to make the temperature more uniform, it is generally not conceivable to provide an acceleration section in the inlet chamber, because the melt plastics simply accelerated only pass through the split holes and into the mold more quickly, which not only does not make the temperature of the melt plastics more uniform, but rather may make the temperature of the melt plastics less likely to become uniform because it enters the mold more quickly.

In the hot nozzle assembly of the hot runner system, the split nozzle core part is positioned in the sprue bush, a heat insulation gap is arranged between the outer peripheral wall of the split nozzle core positioned in the sprue bush and the inner wall of the sprue bush, the end part of the split nozzle core positioned in the sprue bush is provided with an annular convex edge, and the outlet of each split flow hole is positioned at the inner side of the annular convex edge.

The body, the split nozzle core and the sprue bush are all made of metal materials, so that the temperature of melt plastics changes greatly for reducing heat transfer, and a heat insulation gap is arranged between the outer peripheral wall of the split nozzle core positioned in the sprue bush and the inner wall of the sprue bush. However, in actual production, since the melt plastic is in a flowing state, the melt plastic inevitably flows to the outer peripheral wall of the split nozzle core when flowing out from the outlet of the split hole, so that the melt plastic is easy to be extruded into the heat insulation gap, the melt plastic extruded into the heat insulation gap is solidified to a certain extent when the die is not used, and a new melt plastic inevitably contacts with an old melt plastic positioned in the heat insulation gap when the die is used again, so that the temperature at which the new melt plastic is uniformly mixed is sucked away by the part of melt plastic, and the product quality is affected.

The annular convex edge is arranged at the end part of the split nozzle core positioned in the sprue bush, and the outlet of each split hole is positioned at the inner side of the annular convex edge, so that the melt plastics can be prevented from being extruded into the heat insulation gap as much as possible, and the temperature at which the melt plastics are uniformly mixed can be basically maintained stable, and the product quality can be ensured.

In the hot nozzle assembly of the hot runner system, the gate is arranged in the gate sleeve, the gate sleeve at the gate comprises a straight Duan Yi, a first contraction section, a straight Duan Er and a second contraction section in sequence along the axial direction, the inner wall of the gate at the first contraction section has a taper, the maximum inner diameter of the gate at the first contraction section is the same as the inner diameter of the gate at the first straight section, the minimum inner diameter of the gate at the first contraction section is the same as the inner diameter of the gate at the second straight section, the inner wall of the gate at the second contraction section has a taper, the maximum inner diameter of the gate at the second contraction section is the same as the inner diameter of the gate at the second straight section, the annular flange is positioned in the first contraction section, the heat insulation gap is positioned between the outer peripheral wall of the split nozzle core and the inner wall of the gate at the first straight section, and the inner diameter of the annular flange is positioned between the maximum inner diameter and the minimum inner diameter of the gate at the first contraction section.

The annular flange is located in the first constriction so that the molten plastic, after flowing out of the flow dividing opening, drops down the inner wall of the annular flange onto the first constriction. Because the inner wall of the pouring gate at the first part of the contraction section has taper, when the melt plastic falls on the inner wall of the pouring gate at the first part of the contraction section, the melt plastic can directly slide down by means of the acceleration of taper, so that the melt plastic is more difficult to squeeze into the heat insulation gap.

Further, the sprue bush at the sprue comprises a straight Duan Yi, a first shrinkage section, a straight Duan Er and a second shrinkage section along the axial direction, the inner wall of the sprue at the first shrinkage section is provided with taper, the maximum inner diameter of the sprue at the first shrinkage section is the same as the inner diameter of the sprue at the first shrinkage section, the minimum inner diameter of the sprue at the first shrinkage section is the same as the inner diameter of the sprue at the second shrinkage section, the inner wall of the sprue at the second shrinkage section is provided with taper, the maximum inner diameter of the sprue at the second shrinkage section is the same as the inner diameter of the sprue at the second shrinkage section, and the molten plastic can be accelerated twice in the sprue, wherein the first acceleration is mainly for avoiding the molten plastic from being difficult to squeeze into a heat insulation gap, and the second acceleration is for improving the injection speed of the molten plastic into the cavity of the die.

In the hot nozzle assembly of the hot runner system, the cross section of the flow dividing hole is approximately regular hexagon.

The distances from the six inner side walls of the flow dividing hole to the central axis of the flow dividing hole are not identical, so that the actually obtained turbulence effect is better.

Compared with the prior art, the hot nozzle component of the hot runner system comprises the accelerating section and the retaining section along the axial direction by arranging the inlet cavity of the flow dividing nozzle core, and the flow disturbing surface is arranged on the top surface of the protruding part positioned on the retaining section, the accelerating section can accelerate the melt plastic and has larger kinetic energy, after the accelerated melt plastic enters the retaining section, a part of the accelerated melt plastic directly impacts the flow disturbing surface and is sputtered in a wider range around, and the splashed melt plastic can impact the rest melt plastic, so that the flow of the melt plastic is disturbed to a certain extent and is similar to the stirring state, and the melt plastic can be fully mixed before being divided by each flow dividing hole, so that the temperature of the melt plastic entering the die can be more uniform, and the quality of products is improved.

Drawings

FIG. 1 is a cross-sectional view of a hot nozzle assembly of the present hot runner system.

Fig. 2 is an enlarged partial cross-sectional view of the diverter nozzle core of fig. 1.

Fig. 3 is a schematic perspective view of a tap core.

Fig. 4 is another angular perspective view of a tap core.

FIG. 5 is a schematic view of the hot nozzle assembly attached to a manifold.

FIG. 6 is a schematic flow diagram of molten plastic within an inlet chamber.

In the figure, 1, a body; 2. a sprue bush; 2a, pouring gate; 2b, straight section one; 2c, shrinking section one; 2d, straight Duan Er; 2e, contracting section II; 2f, a discharging channel; 3. a shunt nozzle core; 3a, an inlet chamber; 3b, a protruding part; 3b1, a turbulence surface; 3c, a shunt hole; 3d, a drainage part; 3e, an acceleration section; 3f, a holding section; 3g, annular convex edges; 4. a thermal insulation gap; 5. a diverter plate; 6. and a heating ring.

Detailed Description

The following are specific embodiments of the present invention and the technical solutions of the present invention will be further described with reference to the accompanying drawings, but the present invention is not limited to these embodiments.

As shown in fig. 1, 2 and 3, the hot nozzle assembly of the hot runner system comprises a long tubular body 1, a sprue bush 2 fixedly connected to one end of the body 1, and a split nozzle core 3 fixed therebetween, wherein the body 1, the sprue bush 2 and the split nozzle core 3 are all made of metal materials. The flow dividing nozzle core 3 is columnar, an inlet cavity 3a is arranged at one end of the flow dividing nozzle core 3 far away from the sprue bush 2, a protruding part 3b is arranged in the inlet cavity 3a of the flow dividing nozzle core 3, a plurality of flow dividing holes 3c with inlets uniformly distributed around the protruding part 3b are arranged on the flow dividing nozzle core 3, the protruding part 3b is provided with an outer peripheral surface and taper on the outer peripheral surface, the outer diameter of the protruding part 3b is gradually increased along the direction close to the sprue bush 2, the inlets of the flow dividing holes 3c are communicated with the inlet cavity 3a, the outlets of the flow dividing holes 3c penetrate through the other end of the flow dividing nozzle core 3, the cross section of each flow dividing hole 3c is approximately polygonal, in the embodiment, approximately regular hexagon, and the cross section of the flow dividing hole refers to the cross section along the direction perpendicular to the center line of the flow dividing hole 3 c. The shunt nozzle core 3 at the inlet cavity 3a sequentially comprises an accelerating section 3e and a holding section 3f along the axial direction, the cavity wall of the inlet cavity 3a at the accelerating section 3e is provided with taper, the maximum inner diameter of the inlet cavity 3a at the accelerating section 3e is the same as the inner diameter of the body 1, and the minimum inner diameter of the inlet cavity is the same as the inner diameter of the inlet cavity 3a at the holding section 3 f. The bulge 3b is positioned in the inlet cavity 3a at the position of the holding section 3a2, the top of the bulge 3b is provided with a disturbing flow surface 3b1, the disturbing flow surface 3b1 is a circular plane, the disturbing flow surface 3b1 is perpendicular to the central axis of the body 1, and the center of the disturbing flow surface 3b1 is collinear with the central axis of the body 1.

As shown in fig. 1, 2 and 4, the other end of the split nozzle core 3 is located in the sprue bush 2, and this end of the split nozzle core 3 is provided with a drainage portion 3d in a protruding manner, and the outlets of the respective split holes 3c are uniformly distributed around the drainage portion 3 d. The sprue bush 2 is internally provided with a sprue 2a, one end of the sprue bush 2 far away from the body 1 is provided with a discharge channel 2f, the discharge channel 2f is communicated with the sprue 2a, and the end part of the drainage part 3d is pointed and is positioned at a communication position in the sprue 2a, which is close to the sprue 2a and the discharge channel 2 f. A heat insulation gap 4 is arranged between the outer peripheral wall of the split nozzle core 3 positioned in the sprue bush 2 and the inner wall of the sprue bush 2, an annular convex edge 3g is further arranged at the end part of the split nozzle core 3 positioned in the sprue bush 2, and the outlets of the split holes 3c are all positioned at the inner side of the annular convex edge 3 g. Specifically, the sprue bush 2 at the gate 2a includes, in order along the axial direction, a straight section 1 b, a shrinkage section 2c, a straight Duan Er d, and a shrinkage section 2e, the inner wall of the gate 2a at the shrinkage section 2c has a taper, the maximum inner diameter of the gate 2a at the shrinkage section 2c is the same as the inner diameter of the gate 2a at the straight section 2b, the minimum inner diameter at the shrinkage section 2c is the same as the inner diameter of the gate 2a at the straight section 2d, the inner wall of the gate 2a at the shrinkage section 2e has a taper, the maximum inner diameter of the gate 2a at the shrinkage section 2e is the same as the inner diameter of the gate 2a at the straight section 2d, the annular flange 3g is located in the shrinkage section 2c, the inner diameter of the annular flange 3g is located between the maximum inner diameter and the minimum inner diameter of the gate 2a at the shrinkage section 2c, the thermal insulation gap 4 is located between the outer peripheral wall of the nozzle core 3 and the inner peripheral wall of the gate 2a at the straight section 2b, and the discharge channel 2f is communicated with the gate 2 e.

When in use, as shown in fig. 5, the other end of the body 1 is connected to the splitter plate 5 of the hot runner system, specifically, the splitter plate 5 is internally provided with a main runner and a splitter opening communicated with the main runner, the other end of the body 1 is fixedly connected to the position of the splitter opening and is in butt joint with the splitter opening, the discharging channel 2f of the sprue bush 2 is in butt joint with a cavity on a die, and a heating ring 6 is fixed outside the body 1. The melt plastic sequentially enters the body 1 through the main runner and the shunt port, and is injected into the cavity of the die through the sprue bush 2. As shown in fig. 6, when the melt plastic enters the inlet cavity 3a from the inside of the body 1, since the split nozzle core 3 at the inlet cavity 3a sequentially includes acceleration sections 3e and 3f in the axial direction, the cavity wall of the inlet cavity 3a at the acceleration section 3e has a taper, the maximum inner diameter of the inlet cavity 3a at the acceleration section 3e is the same as the inner diameter of the body 1, and the minimum inner diameter of the inlet cavity 3a at the acceleration section 3e is the same as the inner diameter of the inlet cavity 3a at the holding section 3f, which causes the flow velocity of the melt plastic to increase when passing through the acceleration section 3e (since the through-flow cross-sectional area at the maximum inner diameter of the inlet cavity 3a at the acceleration section 3e is larger than that at the minimum inner diameter, the flow velocity increases accordingly when the passing amount is unchanged), that is, the melt plastic enters the inlet cavity 3a at the holding section 3f at a larger flow velocity after passing through the acceleration section 3 e. Meanwhile, the protruding part 3b is positioned in the inlet cavity 3a at the position of the holding section 3f, the top of the protruding part is provided with the flow disturbing surface 3b1, and a part of the accelerated melt plastic directly impacts on the flow disturbing surface 3b1 after entering the inlet cavity 3a at the position of the holding section 3f, and the accelerated melt plastic has larger kinetic energy, so that the impact on the flow disturbing surface 3b1 can sputter the rest melt plastic in a wider range around and impact the rest melt plastic, thus the flow of the melt plastic is disturbed to a certain extent and is in a state similar to that of being stirred, and the melt plastic can be fully mixed before being shunted by each flow dividing hole 3c, and the temperature of the melt plastic is ensured to be uniform.

After that, the melt plastic enters each of the flow dividing holes 3c to be divided, and as the cross section of the flow dividing hole 3c is approximately regular hexagon, when the melt plastic passes through the flow dividing hole 3c, six inner side walls of the flow dividing hole 3c form resistance to the radially outward expanding waves of the melt plastic and generate reaction force to the melt plastic, so that a turbulent stirring effect on the melt plastic is formed in the flow dividing hole 3c, and the temperature of the melt plastic is further and more uniform. Moreover, the distances from the six inner side walls of the flow dividing hole 3c to the central axis thereof are not exactly the same, so that the turbulence effect on the molten plastic is more obvious. After flowing out from each of the tap holes 3c, the molten plastic flows into the gate 2a and finally is injected into the cavity of the mold from the discharge passage 2 f.

The specific embodiments described herein are offered by way of example only to illustrate the spirit of the invention. Those skilled in the art may make various modifications or additions to the described embodiments or substitutions thereof without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.

Claims (4)

1. The hot nozzle component of the hot runner system comprises a long tubular body (1), a sprue bush (2) fixedly connected with one end of the body (1) and a flow dividing nozzle core (3) fixed between the sprue bush and the sprue bush, wherein one end of the flow dividing nozzle core (3) far away from the sprue bush (2) is provided with an inlet cavity (3 a) and the flow dividing nozzle core (3) is provided with a bulge (3 b) in the inlet cavity (3 a), the flow dividing nozzle core (3) is provided with a plurality of flow dividing holes (3 c) distributed around the bulge (3 b), the hot runner system is characterized in that the flow dividing nozzle core (3) at the inlet cavity (3 a) sequentially comprises an accelerating section (3 e) and a holding section (3 f) along the axial direction, the cavity wall of the inlet cavity (3 a) at the accelerating section (3 e) is provided with taper, the maximum inner diameter of the inlet cavity (3 a) at the accelerating section (3 e) is the same as the inner diameter of the body (1) and the minimum inner diameter thereof is the same as the inner diameter of the inlet cavity (3 a) at the holding section (3 f), the bulge (3 b) is positioned in the inlet cavity (3 a) at the holding section (3 f) and the top thereof is provided with a flow disturbing surface (3 b 1), the cross section of the flow distributing hole (3 c) is approximately polygonal, the bulge (3 b) is provided with external taper, the flow disturbing surface (3 b 1) is a circular plane, the turbulence surface (3 b 1) is perpendicular to the central axis of the body (1), and the center of the turbulence surface (3 b 1) is collinear with the central axis of the body (1).

2. The hot nozzle assembly of the hot runner system according to claim 1, wherein the split nozzle core (3) is partially located in the sprue bush (2), a heat insulation gap (4) is formed between the outer peripheral wall of the split nozzle core (3) located in the sprue bush (2) and the inner wall of the sprue bush (2), an annular convex edge (3 g) is formed at the end part of the split nozzle core (3) located in the sprue bush (2), and the outlet of each split hole (3 c) is located inside the annular convex edge (3 g).

3. The hot nozzle assembly of claim 2, wherein the sprue bush (2) is provided with a sprue (2 a), the sprue bush (2) at the sprue (2 a) comprises a straight section one (2 b), a shrinkage section one (2 c), a straight section Duan Er (2 d) and a shrinkage section two (2 e) in sequence along the axial direction, the inner wall of the sprue (2 a) at the shrinkage section one (2 c) is provided with a taper, the maximum inner diameter of the sprue (2 a) at the shrinkage section one (2 c) is the same as the inner diameter of the sprue (2 a) at the straight section one (2 b), the minimum inner diameter of the sprue (2 a) at the shrinkage section one (2 c) is the same as the inner diameter of the sprue (2 a) at the straight section Duan Er (2 d), the maximum inner diameter of the sprue (2 a) at the shrinkage section two (2 e) is the same as the inner diameter of the sprue (2 a) at the straight section one (2 d), the annular flange (3 g) is located between the inner diameter of the sprue (2 a) at the shrinkage section one (2 c) and the maximum inner diameter of the sprue (2 g) at the annular flange (2 c) along the inner diameter of the first end (2 c).

4. A hot nozzle assembly of a hot runner system according to claim 1, characterized in that the cross-section of the diverting aperture (3 c) is substantially regular hexagonal.

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