CN115871163A

CN115871163A - Multi-insert cladding injection molding process

Info

Publication number: CN115871163A
Application number: CN202211581125.9A
Authority: CN
Inventors: 龚红宇; 吴林彬
Original assignee: Longwei Technology Foshan Co ltd
Current assignee: Longwei Technology Foshan Co ltd
Priority date: 2022-12-09
Filing date: 2022-12-09
Publication date: 2023-03-31

Abstract

The invention belongs to the technical field of insert injection molding, and particularly relates to a multi-insert cladding injection molding process which comprises the steps of S1 obtaining insert size data, molding an insert groove matched with an insert through molding, S2 adding hot-melted injection molding raw materials into the insert groove and closing the mold, cooling to obtain an injection bottom layer, S3 preheating the insert to enable the insert to expand, then placing the insert into the insert groove attached with the injection bottom layer, controlling the temperature of the insert groove to be constant, S4 adding the hot-melted injection molding raw materials to perform injection molding, and then sequentially performing pressure maintaining cooling and demolding to obtain an injection insert product.

Description

Multi-insert cladding injection molding process

Technical Field

The invention relates to the technical field of insert injection molding, in particular to a multi-insert cladding injection molding process.

Background

The metal insert injection molding process mainly comprises the steps of placing a metal insert serving as an injection molding insert in a mold in advance, then injecting plastic into the mold, solidifying and cooling, and thus forming the metal insert and the plastic into a whole to obtain a metal insert injection molding product.

The metal insert injection molding product is widely used, for example, the metal insert injection molding process can be applied to the manufacturing of electronic handheld equipment shells, metal resources can be saved, and the strength of plastic parts can be improved. At the same time, they are also used in the automotive field for reducing the weight of automobiles.

The traditional metal insert injection molding process generally adopts a press-in molding method, and when the press-in molding method is used, the gap of each structure on the metal insert is required to meet a certain width, so that the precision of the whole metal insert is reduced, and the strength is also reduced.

Disclosure of Invention

This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.

Therefore, the invention aims to provide a multi-insert cladding injection molding process, which can reduce the probability that an insert and an injection molding layer positioned on the surface of the insert are easy to fall off under stress, and solve the problem that the process of reassembling the insert after injection molding of a plastic part is complicated.

In order to solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

a multi-insert cladding injection molding process comprises the following steps:

s1, obtaining insert size data, and forming an insert groove matched with the insert;

s2, adding the hot-melted injection molding raw material into the insert groove, closing the mold, and cooling to obtain an injection molding bottom layer;

s3, preheating the insert to enable the insert to expand, then placing the insert into an insert groove attached with an injection molding bottom layer, and controlling the temperature of the insert groove to be constant;

s4, adding the hot-melted injection molding raw material for injection molding, and then sequentially performing pressure maintaining, cooling and demolding to obtain an injection molding insert product;

s5, in order to prevent the metal insert from being pulled out, an annular groove can be lathed in the middle of the insert, and when injection molding is carried out, injection molding raw materials enter the annular groove and are matched with the annular groove.

As a preferable scheme of the multi-insert coating injection molding process of the invention, the process comprises the following steps: in the step S4, in order to make the insert and the plastic member tightly combined, the surface of the insert should be knurled or processed with grooves to increase friction force, so that the insert is not easy to be pulled out and rotate during use.

As a preferable scheme of the multi-insert overmolding process of the invention, wherein: in step S4, in order to facilitate the placement and positioning of the insert in the mold, the portion of the mold where the insert is placed should be designed to be cylindrical, so as to facilitate the placement of the insert in the relevant positioning circular hole on the mold.

As a preferable scheme of the multi-insert coating injection molding process of the invention, the process comprises the following steps: if the placing angle of the insert is required, a positioning structure is required to be arranged to ensure that the insert can be quickly and reliably positioned when being placed into the mold.

As a preferable scheme of the multi-insert overmolding process of the invention, wherein: in the step S5, the bottom of the insert may also be lathed into an external thread shape, and when the step S4 is performed, a section of non-threaded area should be set in the injection molding process to prevent the melt from penetrating into the mold.

As a preferable scheme of the multi-insert coating injection molding process of the invention, the process comprises the following steps: the injection molding raw material is selected from one or more of aliphatic nylon, semi-aromatic nylon, wholly aromatic nylon or alicyclic nylon, the nylon is a commonly used material in engineering, the strength meets the requirement, the density is low, and the quality of the integral insert can be reduced.

As a preferable scheme of the multi-insert overmolding process of the invention, wherein: when setting up the inserts in the boss, for guaranteeing that the inserts combines stably to and the intensity of plastic substrate, the inserts should stretch into the bottom of boss, nevertheless need to guarantee minimum end thickness, and the fillet should be made to the inserts head, and to running through the inserts, its height should be less than the high 0.05mm of the shaping of die cavity about to avoid crushing inserts and die cavity slightly.

As a preferable scheme of the multi-insert overmolding process of the invention, wherein: and in the step S2, the mold temperature is controlled to be 65-90 ℃, and in the step S2, the insert can be heated and expanded by an external heating device and then placed into an injection mold and the mold is closed, wherein the heating temperature is controlled to be 65-90 ℃.

Compared with the prior art:

1. compared with a press-in forming method, the injection molding method adopting direct bonding of the hot-melted injection molding raw material and the insert has the advantages that the gap of the metal insert can be designed to be narrower, the forming reliability of a composite product is higher, the probability that the insert and an injection molding layer positioned on the surface of the insert are easy to fall off under stress is reduced, and the problem that the process of assembling the insert again after injection molding of plastic parts is complicated is solved.

2. In order to make the insert and the plastic piece combined tightly, the surface of the insert should be knurled or processed with grooves to increase friction force, so that the insert is not easy to be pulled out in use, does not rotate, and the like.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail with reference to the accompanying drawings and detailed embodiments, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise. Wherein:

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described herein, and it will be apparent to those of ordinary skill in the art that the present invention may be practiced without departing from the spirit and scope of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.

Next, the present invention will be described in detail with reference to the drawings, wherein for convenience of illustration, the cross-sectional view of the device structure is not enlarged partially according to the general scale, and the drawings are only examples, which should not limit the scope of the present invention. In addition, the three-dimensional dimensions of length, width and depth should be included in the actual fabrication.

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The invention provides a multi-insert cladding injection molding process, which refers to fig. 1 and comprises the following steps:

in the step S2, the mold temperature is controlled to be 65-90 ℃, and in the step S2, the insert can be heated and expanded by an external heating device and then placed into an injection mold and the mold is closed, wherein the heating temperature is controlled to be 65-90 ℃.

S3, preheating the insert to enable the insert to expand, then placing the insert into the insert groove attached with the injection bottom layer, and controlling the temperature of the insert groove to be constant;

in the step S4, in order to make the insert and the plastic piece combined tightly, knurling or processing a groove on the surface of the insert to increase friction force, so that the insert is not easy to pull out and does not rotate when in use;

in step S4, in order to facilitate the placement and positioning of the insert in the mold, the portion of the insert placed in the mold should be designed to be cylindrical, so that the insert is placed in the related positioning circular hole on the mold, if the placement angle of the insert has a requirement, a positioning structure is further required to ensure that the insert is placed in the mold to be positioned quickly and reliably, and if the placement angle of the insert has a requirement, a positioning structure is further required to ensure that the insert is placed in the mold to be positioned quickly and reliably.

In step S5, the bottom of the insert may also be lathed into an external thread shape, and in step S4, a section of non-threaded area should be set in the injection molding process to prevent the melt from penetrating into the mold.

Wherein: the injection molding raw material is selected from one or more of aliphatic nylon, semi-aromatic nylon, wholly aromatic nylon or alicyclic nylon, the nylon is a commonly used material in engineering, the strength meets the requirement, the density is low, and the quality of the integral insert can be reduced;

when setting up the inserts in the boss, for guaranteeing that the inserts combines stably to and the intensity of plastic substrate, the inserts should stretch into the bottom of boss, nevertheless need to guarantee minimum end thickness, and the fillet should be made to the inserts head, and to running through the inserts, its height should be less than the high 0.05mm of the shaping of die cavity about to avoid crushing inserts and die cavity slightly.

Compared with a press-in forming method, the injection molding process adopts the injection molding method of directly jointing the injection molding raw material and the insert after hot melting, the gap of the metal insert can be designed to be narrower, the forming reliability of a composite product is higher, the probability that the insert and an injection molding layer positioned on the surface of the insert are easy to fall off under stress is reduced, and the problem that the process of assembling the insert again after injection molding of plastic parts is complicated is solved.

In addition, in order to make the insert and the plastic piece combined tightly, the surface of the insert should be knurled or processed with grooves to increase friction force, so that the insert is not easy to be pulled out and does not rotate in use, and in order to facilitate the placement and positioning of the insert in the mold, the part of the insert placed in the mold should be designed into a cylindrical shape, so that the insert is placed in a related positioning round hole on the mold.

While the invention has been described above with reference to an embodiment, various modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In particular, the various features of the disclosed embodiments of this invention can be used in any combination as long as there is no structural conflict, and the combination is not exhaustively described in this specification merely for the sake of brevity and resource savings. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. The multi-insert cladding injection molding process is characterized by comprising the following steps of:

2. The multi-insert-piece cladding injection molding process according to claim 1, wherein in step S4, in order to make the insert piece and the plastic piece tightly combined, the surface of the insert piece should be knurled or grooved to increase friction force, so that the insert piece is not easy to be pulled out, not rotated and the like during use.

3. The multiple-insert overmolding process according to claim 1, wherein in step S4, for facilitating the placement and positioning of the insert in the mold, the portion of the insert placed in the mold is designed to be cylindrical, so as to facilitate the placement of the insert in the associated circular positioning hole of the mold.

4. The multi-insert overmolding process of claim 3, wherein if the angle of placement of the inserts requires, positioning structures are further provided to ensure that the inserts can be positioned quickly and reliably when placed in the mold.

5. The multi-insert overmolding process of claim 1, wherein in step S5, the bottom of the insert is also externally threaded, and in step S4, a non-threaded region is provided to prevent the melt from penetrating into the mold.

6. The multi-insert overmolding process according to claim 5, wherein the molding material is selected from one or more of aliphatic nylon, semi-aromatic nylon, wholly aromatic nylon or alicyclic nylon, which are commonly used in engineering, and the nylon has sufficient strength and low density, which can reduce the quality of the integral insert.

7. The multiple-insert overmolding process according to claim 1, wherein, when the insert is provided in the boss, the insert is inserted into the bottom of the boss to ensure the stability of the insert and the strength of the plastic substrate, but the minimum bottom thickness is ensured, the head of the insert is rounded, and the height of the insert penetrating through the insert is slightly lower than the molding height of the cavity by about 0.05mm so as not to crush the insert and the cavity.

8. The multi-insert-piece cladding injection molding process according to claim 7, wherein the mold temperature in the step S2 is controlled to be 65 ℃ to 90 ℃, and the insert piece in the step S2 can be heated and expanded by an external heating device and then placed into an injection mold and the mold is closed, and the heating temperature is controlled to be 65 ℃ to 90 ℃.