阅读说明：本技术 一种塑料外壳与金属内胆滚塑一体成型工艺 (Rotational molding integrated forming process for plastic shell and metal liner ) 是由 曾德华 郭明辉 于 2020-04-10 设计创作，主要内容包括：本发明涉及制冷箱滚塑工艺技术领域,特指一种塑料外壳与金属内胆滚塑一体成型工艺。在本发明中,通过第一模具、第二模具、第三模具与金属内胆一体成型,避免了对滚塑壳体的二次破坏,保证了产品的完整性,并提高了生产效率,节约了施工成本,解决了现有的滚塑工艺中所存在的工艺复杂,导致生产效率低下,产品拼接处缝隙明显以及生产成本高的问题。(The invention relates to the technical field of rotational molding processes of refrigeration cases, in particular to a rotational molding integrated forming process of a plastic shell and a metal liner. According to the invention, the first die, the second die, the third die and the metal liner are integrally formed, so that secondary damage to the rotational molding shell is avoided, the integrity of a product is ensured, the production efficiency is improved, the construction cost is saved, and the problems of low production efficiency, obvious gaps at the splicing position of the product and high production cost caused by complex process in the existing rotational molding process are solved.)

1. A plastic shell and metal liner rotational molding integrated forming process is characterized by comprising the following steps:

s1, fixing the inner container and the second mold;

s2, combining the first mold and the second mold to form a fourth mold, wherein the inner container is arranged in the first mold, and a closed filling space is formed between the inner container and the first mold;

s3, injecting a first filler into the first mold;

s4, combining the third mold and the fourth mold to form a fifth mold;

s5, performing rotational molding, cooling and die opening on the fifth die;

s6, injecting a second filler into the filling space.

2. The rotational molding integrated forming process of the plastic shell and the metal liner according to claim 1, wherein the first mold is shaped like a hollow cuboid, and a first opening and a second opening are respectively formed on the upper side and the right side of the cuboid;

the third mold is in a hollow cuboid shape, four surfaces of the cuboid are integrally enclosed to form a third cavity communicated from left to right, and an outer edge is arranged on the periphery of the third cavity in a surrounding manner;

the second die comprises a concave part and an extension part which are connected with each other, the concave part is concave towards the bottom surface of the first die, and a second cavity is formed; the extension is disposed at the right side of the recess, and the extension may be disposed on the upper face of the third mold.

3. The rotational molding integrated forming process of the plastic shell and the metal liner as claimed in claim 2, wherein in S1, the liner is fixed below the second mold through a fixing structure;

the fixing structure comprises two ejector rods symmetrically arranged at the upper part of the inner container, two ends of the two ejector rods are respectively fixed on two opposite inner side walls of the inner container, iron plates are arranged on the two ejector rods, screws are arranged on the iron plates, and the iron plates are connected with the second mold through the screws; one end of each of the two ejector rods is provided with an adjusting nut.

4. The rotational molding integrated molding process of the plastic shell and the metal liner as claimed in claim 2, wherein in S2, the second mold is placed on the upper portion of the first mold;

the first mold is internally provided with a first cavity, the inner container is arranged in the first cavity, the height of the first cavity is greater than that of the inner container, and the filling space is formed between the first mold and the inner container.

5. The rotational molding and integrated forming process of the plastic shell and the metal liner according to claim 4, wherein the height of the filling space is 40-100 mm.

6. The rotational molding and integrated forming process of the plastic shell and the metal liner according to claim 4, wherein the left and right surfaces of the lower surface of the second mold are pre-deformed inclined surfaces.

7. The rotational molding process for forming the plastic shell and the metal liner integrally as claimed in claim 2, wherein in S3, the first filler is a mixture of LLDPEM735RUP and LLDPE33804RUP in a ratio of 6:4, and the mixture is stirred for 15 minutes, cooled to normal temperature, and then injected into the first mold.

8. The rotational molding process for integrally molding the plastic shell and the metal liner as claimed in claim 2, wherein in S4, the third mold is placed at the right end of the first mold.

9. The rotational molding integrated forming process of the plastic shell and the metal liner as claimed in claim 2, wherein in S5, the rotational molding temperature is 245-250 ℃ and the duration is 1200S; cooling for 200 and 600 seconds after heating; and taking the mold when the surface temperature of the semi-formed product is reduced to 80-85 ℃.

10. The rotational molding and integral forming process of the plastic shell and the metal liner according to claim 2, wherein in S6, the second filler is a polyurethane thermal insulation material.

Technical Field

The invention relates to the technical field of rotational molding processes of refrigeration cases, in particular to a rotational molding integrated forming process of a plastic shell and a metal liner.

Background

Disclosure of Invention

The invention aims to: the invention provides a rotational molding integrated forming process of a plastic shell and a metal liner, and aims to solve the problems that the production efficiency is low, gaps at splicing positions of products are obvious and the production cost is high due to the complex process in the existing rotational molding process.

In order to solve the problems in the prior art, the invention adopts the following technical scheme:

a plastic shell and metal liner rotational molding integrated forming process comprises the following steps:

s1, fixing the inner container and the second mold;

s2, combining the first mold and the second mold to form a fourth mold, wherein the inner container is arranged in the first mold, and a closed filling space is formed between the inner container and the first mold;

s3, injecting a first filler into the first mold;

s4, combining the third mold and the fourth mold to form a fifth mold;

s5, performing rotational molding, cooling and die opening on the fifth die;

s6, injecting a second filler into the filling space.

As an improvement of the technical scheme of the rotational molding integrated forming process of the plastic shell and the metal liner, the first mold is in the shape of a hollow cuboid, and a first opening and a second opening are respectively formed on the upper side and the right side of the cuboid;

the third mold is in a hollow cuboid shape, four surfaces of the cuboid are integrally enclosed to form a third cavity communicated from left to right, and an outer edge is arranged on the periphery of the third cavity in a surrounding manner;

the second die comprises a concave part and an extension part which are connected with each other, the concave part is concave towards the bottom surface of the first die, and a second cavity is formed; the extension is disposed at the right side of the recess, and the extension may be disposed on the upper face of the third mold.

As an improvement of the technical scheme of the rotational molding integrated forming process of the plastic shell and the metal liner, in S1, the liner is fixed below the second mold through a fixing structure;

the fixing structure comprises two ejector rods symmetrically arranged at the upper part of the inner container, two ends of the two ejector rods are respectively fixed on two opposite inner side walls of the inner container, iron plates are arranged on the two ejector rods, screws are arranged on the iron plates, and the iron plates are connected with the second mold through the screws; one end of each of the two ejector rods is provided with an adjusting nut.

As an improvement of the technical solution of the rotational molding integrated process of the plastic housing and the metal liner of the present invention, in S2, the second mold is placed on the upper portion of the first mold;

the first mold is internally provided with a first cavity, the inner container is arranged in the first cavity, the height of the first cavity is greater than that of the inner container, and the filling space is formed between the first mold and the inner container.

As an improvement of the technical scheme of the rotational molding integrated forming process of the plastic shell and the metal liner, the height of the filling space is 40-100 mm.

As an improvement of the technical scheme of the rotational molding integrated forming process of the plastic shell and the metal liner, the left surface and the right surface of the lower surface of the second die are pre-deformed inclined planes.

As an improvement of the technical scheme of the rotational molding and integral forming process of the plastic shell and the metal liner, in S3, the first filler is a mixture of LLDPEM735RUP and LLDPE33804RUP in a ratio of 6:4, the first filler is stirred for 15 minutes and cooled to normal temperature, and then the mixture is injected into a first mold.

As an improvement of the technical solution of the rotational molding integrated process of the plastic housing and the metal liner, in S4, the third mold is placed at the right end of the first mold.

As an improvement of the technical scheme of the rotational molding integrated forming process of the plastic shell and the metal liner, in S5, the rotational molding temperature is 245-250 ℃, and the duration time is 1200S; cooling for 200 and 600 seconds after heating; and taking the mold when the surface temperature of the semi-formed product is reduced to 80-85 ℃.

As an improvement of the technical scheme of the rotational molding integrated forming process of the plastic shell and the metal liner, in S6, the second filler is a polyurethane thermal insulation material.

The invention has the beneficial effects that:

1. in the rotational molding process, the first mold, the second mold, the third mold and the metal liner are integrally molded, so that secondary damage to the rotational molding shell is avoided, the integrity of a product is ensured, the production efficiency is improved, and the construction cost is saved.

2. The invention is an integrally formed product of a plastic inner container of a shell and metal, and the rotationally molded shell can provide design diversity, and has good ultraviolet-proof and ageing-resistant performances, impact resistance and strong collision resistance. The heat conduction and cold conduction performance of the metal inner container is good, the hollow layer is filled with PU heat insulation materials, and the strong functions of the heating insulation box and the refrigerating insulation box can be realized in the box body with the built-in heating or refrigerating equipment.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic view of the split structure of the present invention;

FIG. 3 is a schematic longitudinal cross-sectional structure of the present invention;

FIG. 4 is a schematic structural view of a second mold and an inner container according to the present invention;

FIG. 5 is a perspective view of the present invention;

FIG. 6 is a schematic structural view of a fixing structure according to the present invention;

description of reference numerals: 1-forming a finished product 1; 2-a first mould; 3-a second mold; 4-a third mold; 5-a second cavity; 6-filling the space; 7-a mandril; 8-iron plate; 9-a screw; 10-adjusting the nut; 11-a pre-deformation bevel; 12-a first cavity; 13-inner container; a-height of the filled space.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of embodiments of the present invention, and not all embodiments.

As shown in fig. 1 to 6, a rotational molding and integral forming process of a plastic shell and a metal liner comprises the following steps:

s1, fixing the inner container 13 and the second mold 3;

at S1, the inner container 13 is fixed to the lower surface of the second mold 3 by a fixing structure.

The fixing structure comprises two ejector rods 7 symmetrically arranged on the upper part of the inner container 13, two ends of each ejector rod 7 are respectively fixed on two opposite inner side walls of the inner container 13, iron plates 8 are arranged on the two ejector rods 7, screws 9 are arranged on the iron plates 8, and the iron plates 8 are fixed below the second die 3 through the screws 9. Furthermore, one end of each of the two top rods 7 is provided with an adjusting nut 10.

In detail, taking a single push rod 7 as an example, the push rod 7 is fastened on two opposite inner side walls of the inner container 13 through an adjusting nut 10, the iron plate 8 can be fixedly connected on the two push rods 7 through welding and the like, and then the inner container 13 is fixed below the second mold 3 through a screw 9 on the iron plate 8. Preferably, the inner container 13 is made of metal, but not limited to metal.

Further, the first mold 2 is shaped like a hollow cuboid, and a first opening and a second opening are respectively formed on the upper side and the right side of the cuboid; the third mold 4 is in a hollow cuboid shape, four surfaces of the cuboid are integrally enclosed to form a third cavity communicated from left to right, and an outer edge is arranged around the periphery of the third cavity; the second die 3 comprises a concave part and an extension part which are connected with each other, the concave part is concave towards the bottom surface of the first die 2, and a second cavity 5 is formed; the extension is placed on the right side of the recess, and the extension may be placed on the upper face of the third mold 4.

When the first mold 2 and the second mold 3 are combined, the second mold 3 is arranged at the first opening, the concave part of the second mold 3 is concave towards the bottom surface of the first mold 2, the second mold 3 can be fixed on the first mold 2 through the concave part, and a fourth mold is formed; when the third mold 4 and the fourth mold are combined, the third mold 4 is placed at the right end of the fourth mold from the second opening, the third cavity is communicated with the fourth mold and the outside left and right, the position of the third mold 4 placed in the fourth mold is limited by the outer edge, and a fifth mold is formed.

S2, combining the first mold 2 and the second mold 3 to form a fourth mold, placing the inner container 13 in the first mold 2, and forming a closed filling space 6 between the inner container 13 and the first mold 2;

the second mold 3 is placed on the first mold 2 from above with the first mold 2 as a bottom. The first mold 2 is provided with a first cavity 12, the inner container 13 is arranged in the first cavity 12, and the closed filling space 6 is formed between the inner container 13 and the first mold 2.

In detail, since the inner container 13 is fixed below the second mold 3, the inner container 13 is gradually placed into the first mold 2 in the process of placing the second mold 3 into the upper portion of the first mold 2 from above; when the second mold 3 is fixed on the first mold 2, the inner container 13 is placed in the first mold 2. And as the first cavity 12 is arranged in the first mould 2, the height of the first cavity 12 is greater than that of the inner container 13, and a filling space 6 is formed between the inner container 13 and the first cavity 12. Preferably, the height A of the filling space is 40-100mm, so that the capacity of the inner container can be maximized, and the filling space can be ensured to have enough filling positions.

Further, the left and right surfaces of the lower surface of the second mold 3 are pre-deformed inclined surfaces 11. When placing second mould 3 to the upper portion of first mould 2, not only can make second mould 3 fix on first mould 2 through predeformation inclined plane 11, avoid second mould 3 to take place the position relative to first mould 2 and remove, can also make second mould 3 press close to first mould 2 better through predeformation inclined plane 11.

In detail, because the left and right sides of the lower surface of the second mold 3 are the pre-deformation inclined planes 11, the two pre-deformation inclined planes 11 are inclined from the second mold 3 to the first plastic part, and the two pre-deformation inclined planes 11 are inclined towards the middle part of the first plastic part, the problem of deformation caused by inconsistency of the rotational molding shell and the inner container 13 during cooling shrinkage in the prior art is solved through the two pre-deformation inclined planes 11.

More specifically, as shown in the figure, taking the metal inner container 13 as an example, the length and width dimensions of the lower end of the inclined plane are a and B, wherein 1.035 is the shrinkage coefficient of metal, and the length and width dimensions of the upper end of the inclined plane are a × 1.035 and B × 1.035. The combination part of the metal liner 13 at the lower end of the inclined surface and the plastic can not shrink after the product is demoulded, and the size is unchanged; the plastic at the upper end of the inclined plane is cooled and contracted to change the size into A and B; and the lower end of the inclined plane forms a straight body, so that the problem of deformation caused by inconsistency of the rotational molding shell and the inner container 13 in cooling shrinkage in the prior art is solved.

S3, injecting the first filler into the first mold 2;

the first filler was LLDPEM735RUP and LLDPE33804RUP mixed in a 6:4 ratio, and the mixed first filler was stirred for 15 minutes, cooled to room temperature, and injected into the first mold 2. Based on the characteristics of LLDPEM735RUP and LLDPE33804RUP, after injecting the first filler into the first mold 2, a first plastic part with high surface finish and toughness is obtained, and the first plastic part and the inner container 13 are fixedly connected with each other under the action of the first filler.

S4, combining the third mold 4 and the fourth mold to form a fifth mold;

since the first mold 2 and the second mold 3 are combined to form the fourth mold, the third mold 4 and the fourth mold are combined to form the fifth mold, and the fifth mold is locked and closed. The third die 4 is combined with the fourth die from the right end of the fourth die, and the combined third die 4 is arranged at the right end of the first die 2.

S5, performing rotational molding, cooling and die opening on the fifth die to form a semi-formed finished product;

performing rotational molding on the fifth mold, wherein the temperature of the cavity of the rotational molding machine is kept between 245 ℃ and 250 ℃ for 1200 seconds, so that the plastic can be kept in a molten state, and the rotational molding effect on the fifth mold can also be ensured; and after the rotational molding of the fifth mold is finished, cooling the fifth mold in natural cooling air for 200-600 seconds, gradually cooling and solidifying the plastic in the fifth mold, and opening the mold to take out the semi-formed finished product when the surface temperature of the fifth mold is reduced to 80-85 ℃.

Furthermore, after the formed finished product 1 is taken out, the formed finished product 1 can be shaped and cooled in a cooling clamp, burrs of the cooled formed finished product 1 are removed, burrs are repaired, and the smoothness of the product is kept.

S6, injecting a second filler into the filling space 6 to obtain a molded finished product 1;

in detail, the second mold 3 is provided with a second cavity 5, and the second cavity 5 is disposed above the inner container 13. When injecting the second filler into the filling space 6, the opening of the second cavity 5 is downward, the fifth mold is placed on the special foaming jig for the second filler, and the second filler is injected into the filling space 6, so that the molded product 1 is obtained.

Preferably, the second filler is a polyurethane thermal insulation material, and the polyurethane thermal insulation material is a synthetic material with excellent performance, has the advantages of high specific strength, small thermal conductivity coefficient and the like, and can be used as a thermal insulation material and a structural material.

The special foaming fixture can be customized according to the size of the rotationally molded finished product 1 after cooling and shaping, and the customization requirements are as follows: the mould comprises an upper mould body, a lower mould base, a side mould plate and a locking piece arranged on the side mould plate, wherein the side mould plate is formed by folding a side mould plate and an end mould plate, and the side mould plate and the end mould plate are respectively hinged with the lower mould base, namely the structure for folding the multi-mould plate.

In the invention, the finished product 1 is formed by fastening the metal liner 13 and the rotational molding die together, and the effect of integrally forming the rotational molding shell and the metal liner 13 is realized through the arrangement.

All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.