CN110640970B

CN110640970B - Method for processing functional hole of electronic product shell and insert adopted by same

Info

Publication number: CN110640970B
Application number: CN201910791065.5A
Authority: CN
Inventors: 欧阳文兵; 陈景安; 罗伟湛; 李胜; 梅秀前
Original assignee: Guangdong Evenwin Precision Technology Co Ltd
Current assignee: Guangdong Evenwin Precision Technology Co Ltd
Priority date: 2019-08-26
Filing date: 2019-08-26
Publication date: 2022-07-15
Anticipated expiration: 2039-08-26
Also published as: CN110640970A

Abstract

The invention relates to a method for processing a functional hole of an electronic product shell and an insert adopted by the method. The electronic product casing includes relative outside and the inside that sets up, seted up the profile hole on the outside and with the profile hole is located the locating hole with one side, the profile hole with inside intercommunication, this mold insert includes: a body; the material blocking piece is arranged on the body in a protruding mode and can be inserted into the contour hole, the shape of the material blocking piece is the same as that of the contour hole, and gaps with equal intervals are formed between the outer side face of the material blocking piece and the inner side face of the contour hole; and the guide post is arranged on the body in a protruding mode, is positioned on the same side of the body as the material blocking part, and is matched with the positioning hole for guiding when the material blocking part is inserted into the contour hole. The insert can be used for assisting in injection molding in a functional hole of a shell of an electronic product, and can ensure that the thickness of injection-molded plastic is uniform.

Description

Method for processing functional hole of electronic product shell and insert adopted by same

Technical Field

The invention relates to the technical field of electronic product shell processing, in particular to a processing method of a functional hole of an electronic product shell and an adopted insert thereof.

Background

At present, a circle of plastic structure wraps the USB of the mobile phone and the metal contour holes of the earphones. The plastic structure is usually formed by the following steps: firstly, CNC processes out the metal contour hole of USB and earphone on the cell-phone casing, then moulds plastics with the metal contour hole and fill up the plastic, removes the middle part of plastic through CNC processing at last, only remains a round of plastic. According to the forming mode, when CNC machining is used for removing the plastic, dynamic operation is performed, the machining accuracy is difficult to guarantee, and the phenomenon that the reserved plastic is uneven in thickness often occurs.

Disclosure of Invention

Therefore, it is necessary to provide an insert which can be used for assisting injection molding in a functional hole of an electronic product housing and can ensure uniform thickness of injection molded plastic, and a method for processing the functional hole of the electronic product housing by using the insert, aiming at the problem that the effect of the injection molded plastic in the functional hole of the electronic product housing is not good.

An insert for functional hole molding of an electronic product housing, the electronic product housing comprising an exterior and an interior disposed opposite to each other, the exterior having a contour hole and a positioning hole on the same side as the contour hole, the contour hole communicating with the interior, the insert comprising: a body; the material blocking piece is arranged on the body in a protruding mode and can be inserted into the contour hole, the shape of the material blocking piece is the same as that of the contour hole, and gaps with equal intervals are formed between the outer side face of the material blocking piece and the inner side face of the contour hole; and the guide post is arranged on the body in a protruding mode, is positioned on the same side of the body as the material blocking part, and is matched with the positioning hole for guiding when the material blocking part is inserted into the contour hole.

Above-mentioned mold insert can insert through keeping off the material piece and locate the contour hole downtheholely, and when keeping off the material piece and insert the contour hole, inserts the downthehole direction of locating hole through the guide pillar, can guarantee to keep off that the material piece inserts the downthehole position of contour is accurate, keeps off and forms equidistant clearance between the lateral surface of material piece and the medial surface of contour hole, then, pours plastics the plastic into to the clearance, treats to take out the mold insert behind the plastic shaping, can guarantee the downthehole even plastic of thickness that forms of contour. Compared with the conventional operation that the insert is injected into the contour hole to be filled with the plastic and then the plastic in the middle part is removed through CNC machining, the injection molding mode of the insert has higher efficiency, the machining cost of deburring after CNC machining can be eliminated, and meanwhile, the labor cost and the use cost of a machine table and CCD (charge coupled device) image positioning equipment adopted by CNC machining can be saved.

In one embodiment, two positioning holes are provided, two positioning blocks are respectively arranged on two sides of the contour hole, two guide posts are respectively arranged on two sides of the material blocking part, and the guide posts are matched with the positioning holes in a one-to-one correspondence manner. Two-point positioning guide can be formed by arranging the two guide columns, so that the material blocking part can be more accurately inserted into the corresponding position of the contour hole, and the position deviation cannot occur.

In one embodiment, the contour hole comprises a peripheral hole and an injection molding hole, the peripheral hole is formed by the outer portion being sunken towards the inner portion, and the injection molding hole is formed in the bottom wall of the peripheral hole and communicated with the inner portion; keep off the material piece and include first bumping post and second bumping post, first bumping post is outstanding to be located on the body, the second bumping post is outstanding to be located first bumping post is kept away from on one side of body, first bumping post is inserted and is located peripheral downthehole, the second bumping post is inserted and is located in the hole of moulding plastics, just the appearance of second bumping post with the appearance in hole of moulding plastics is the same, the lateral surface of second bumping post with equidistant clearance has between the medial surface in hole of moulding plastics. Peg graft in peripheral downthehole by first bumping post to form the plastic between second bumping post and the hole of moulding plastics, then can polish through CNC processing and get rid of peripheral hole, only remain hole and plastic of moulding plastics, can form stable in structure, the better functional pore structure of intensity.

In one embodiment, the first retaining post completely blocks the peripheral hole to prevent plastic from flowing from the injection hole into the peripheral hole. Carry out the shutoff through first bumping post to peripheral hole for the plastic can only be formed in moulding plastics downtheholely, still need get rid of the plastic in the peripheral hole when avoiding processing to form the function hole.

In one embodiment, the inner diameter of the peripheral hole is larger than that of the injection molding hole, the sectional area of the first retaining column is larger than that of the second retaining column, and the first retaining column and the peripheral hole are the same in shape and size. The effect that the first bumping post blocks the peripheral hole to prevent plastic from flowing into the peripheral hole from the injection molding hole is better.

The invention also provides a processing method of the functional hole of the electronic product shell, which comprises the following steps: processing a contour hole and a positioning hole on the outer part of the electronic product shell; the insert is inserted into the contour hole, and the guide post is inserted into the positioning hole for guiding, so that the material blocking piece is inserted into the contour hole, and a gap with equal interval is formed between the material blocking piece and the contour hole; injecting plastic between the material blocking part and the contour hole; extracting the insert from the electronic product shell; and processing and removing part of the outside of the electronic product shell, and exposing the end face of the plastic. According to the processing method, the insert is inserted into the contour hole and guided by the guide pillar and the positioning hole in a matching mode, so that a gap is formed between the insert and the contour hole, then plastic is injected between the insert and the contour hole, the plastic with uniform thickness can be formed quickly and stably, and after part of the outer portion of the shell of the electronic product is processed and removed, the functional hole with stable structure and better strength can be formed.

In one embodiment, in the step of inserting the insert into the contour hole, the electronic product housing is specifically positioned in a mold, and then the insert is driven to be inserted into the contour hole by a driving device. The automatic insert inserting and locating device has the advantages that the automatic insert inserting and locating device can be automatically driven to insert into the contour hole, operation is convenient, and efficiency is higher.

In one embodiment, in the step of inserting the insert into the contour hole, the body completely abuts against the outside of the electronic product housing, and the guide post abuts against the bottom wall of the positioning hole, so that the stopper is completely inserted into the contour hole. Through the body and the outside of electronic product paste tightly to and the diapire butt of guide pillar and locating piece, can guarantee to keep off the material piece and can insert and establish in place in the contour hole on the basis that the direction is stabilized in the formation.

In one embodiment, in the step of injecting plastic, plastic is injected from the inside of the electronic product housing to between the material blocking member and the contour hole, and the gap is filled with the plastic. The injection molding mode is more convenient to operate, and a more stable plastic structure can be formed.

In one embodiment, the electronic product housing is a metal housing, and before the step of inserting the insert into the contour hole, the hole wall of the contour hole is laser engraved. The structural stability of metal casing is better, and downthehole radium carving back of metal profile, can be so that the stability that the plastic that produces combines of moulding plastics is better.

Drawings

Fig. 1 is a schematic structural view of an insert of the present invention inserted in a housing of an electronic product;

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

FIG. 3 is a schematic view of a portion of the enlarged structure shown at A in FIG. 1;

FIG. 4 is a schematic view of a portion B shown in FIG. 2;

FIG. 5 is a schematic diagram of an embodiment of the insert shown in FIG. 1;

FIG. 6 is a schematic diagram of a first fitting structure of the insert and the housing of the electronic product after plastic injection;

FIG. 7 is an enlarged partial view of the structure shown at C in FIG. 6;

FIG. 8 is a schematic diagram of a second fitting structure of the insert and the electronic product housing after plastic injection molding;

fig. 9 is a schematic structural diagram of an embodiment of an electronic product housing after a functional hole is finally formed in the electronic product housing.

In the drawings, the components represented by the respective reference numerals are listed below:

1. embedding; 11. a body; 12. a material blocking part; 121. a first bumping post; 122. a second bumping post; 13. a guide post; 2. an electronic product housing; 21. a functional hole; 22. a contour hole; 221. a peripheral hole; 222. injection molding holes; 23. positioning holes; 3. a gap; 4. and (3) plastic cement.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, embodiments accompanying 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. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather should be construed as broadly as the present invention is capable of modification in various respects, all without departing from the spirit and scope of the present invention.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a single embodiment.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

Referring to fig. 1 and 2, in an embodiment, an insert 1 for forming a functional hole 21 of an electronic product housing 2 includes an outer portion and an inner portion, where the outer portion is substantially equal to a periphery of the electronic product housing 2 and is communicated with an external environment, and the inner portion is substantially used for disposing an electronic component. The outline hole 22 and the positioning hole 23 are opened on the outside, the positioning hole 23 and the outline hole 22 are located on the same side of the electronic product housing 2, and the outline hole 22 communicates with the inside. The insert 1 comprises a body 11, a material blocking part 12 and a guide post 13. The body 11 may be configured as a long strip shape, or other shapes that can match the external shape of the electronic product housing 2. The material blocking part 12 and the guide post 13 are protruded on the body 11, and the material blocking part 12 and the guide post 13 are spaced on the same side of the body 11. The material blocking piece 12 can be inserted into the contour hole 22, the shape of the material blocking piece 12 is the same as that of the contour hole 22, and the gaps 3 with equal intervals are formed between the outer side face of the material blocking piece 12 and the inner side face of the contour hole 22; the guide posts 13 can be matingly inserted into the positioning holes 23.

Referring to fig. 3, the insert 1 can be inserted into the contour hole 22 through the material blocking member 12, and when the material blocking member 12 is inserted into the contour hole 22, the material blocking member 12 can be inserted into the positioning hole 23 through the guide post 13 for guiding, so that the position of the material blocking member 12 inserted into the contour hole 22 is accurate, the gap 3 with equal spacing is formed between the outer side surface of the material blocking member 12 and the inner side surface of the contour hole 22, then, the plastic 4 is injected into the gap 3, and after the plastic 4 is molded, the insert 1 is taken out, so that the plastic 4 with uniform thickness can be formed in the contour hole 22. Compared with the conventional operation of injecting plastic into the contour hole 22 to fill the plastic and then removing the plastic at the middle part by CNC (computerized numerical control) machining, the injection molding mode of inserting the insert 1 has higher efficiency, can cancel the machining cost of deburring after CNC machining, and can save the labor cost and the use cost of a machine table and CCD (charge coupled device) image positioning equipment adopted by CNC machining.

Referring to fig. 4, in an embodiment, the contour hole 22 includes a peripheral hole 221 and an injection hole 222, the peripheral hole 221 is formed by an outer portion of the electronic product casing 2 being recessed inward, the injection hole 222 is opened on a bottom wall of the peripheral hole 221, an inner diameter of the peripheral hole 221 is larger than an inner diameter of the injection hole 222, and the injection hole 222 is communicated with an inner portion of the electronic product casing 2. Referring to fig. 5, the material blocking member 12 includes a first blocking pillar 121 and a second blocking pillar 122, the first blocking pillar 121 protrudes from a side surface of the body 11, the second blocking pillar 122 protrudes from a side surface of the first blocking pillar 121 away from the body 11, the shape of the second blocking pillar 122 is the same as that of the injection molding hole 222, and the size of the second blocking pillar 122 is slightly smaller than that of the injection molding hole 222. Referring to fig. 6 and 7, when the material blocking member 12 is inserted into the contour hole 22, the first blocking pillar 121 is inserted into the peripheral hole 221, the second blocking pillar 122 is inserted into the injection hole 222, and the gap 3 is formed between the outer side surface of the second blocking pillar 122 and the inner side surface of the injection hole 222, the plastic 4 is specifically injection molded in the gap 3 between the second blocking pillar 122 and the injection hole 222, and the semi-finished product of the functional hole 21 shown in fig. 8 is obtained, and then the peripheral hole 221 is removed by CNC, and only the injection hole 222 and the plastic 4 are remained, so that the functional hole 21 with stable structure and better strength can be formed.

In another embodiment, the cross-sectional area of the first retaining post 121 is greater than the cross-sectional area of the second retaining post 122, and the first retaining post 121 is the same size as the peripheral hole 221. When the material blocking part 12 is inserted into the contour hole 22, the peripheral hole 221 is completely blocked by the first blocking column 121, so that the plastic 4 can only be formed in the injection molding hole 222, and the plastic 4 in the peripheral hole 221 is prevented from being removed when the functional hole 21 is machined and molded.

Referring to fig. 5 and 6, in an embodiment, in order to ensure that the material blocking member 12 is inserted into the contour hole 22 and guided more accurately, two positioning holes 23 are formed on the exterior of the electronic product housing 2, and the two positioning blocks are respectively disposed on two sides of the contour hole 22. Two guide posts 13 are also arranged, the two guide posts 13 are respectively arranged at two sides of the material blocking part 12, and the guide posts 13 are matched with the positioning holes 23 in a one-to-one correspondence manner. Two-point positioning guide can be formed by arranging the two guide pillars 13, so that the material blocking part 12 can be more accurately inserted into the corresponding position of the contour hole 22 without position deviation, and the distance between the second material blocking pillar 122 and the injection hole 222 is equal, so that the thickness of the injection molded plastic 4 is uniform.

It can be understood that, in order to enable the insert 1 to be inserted into the contour hole 22 and the positioning hole 23 more smoothly, a chamfer, specifically a rounded corner, is provided on one end of the guide pillar 13 away from the body 11, so as to facilitate the rapid matching and insertion of the guide pillar 13 and the positioning hole 23; a chamfer, specifically a fillet, is also arranged at one end of the first bumping post 121 far away from the body 11; a chamfer or a fillet is also provided at an end of the second bumping post 122 far from the first bumping post 121, so that the first bumping post 121 and the peripheral hole 221 are inserted more smoothly, and the second bumping post 122 and the injection molding hole 222 are inserted more smoothly.

The invention also discloses a method for processing the functional hole 21 of the electronic product shell 2,

in one embodiment, the processing method comprises the following steps:

CNC machining a contour hole 22 and a positioning hole 23 on the outer part of the electronic product shell 2;

the insert 1 is inserted into the contour hole 22, the guide post 13 is inserted into the positioning hole 23 for guiding, the material blocking part 12 is inserted into the contour hole 22, and the gaps 3 with equal intervals are kept between the material blocking part 12 and the contour hole 22;

injecting plastic 4 between the material blocking part 12 and the contour hole 22, and drawing out the insert 1 from the electronic product shell 2 after the plastic 4 is molded;

and (3) machining and removing part of the outer part of the electronic product shell 2, polishing the positioning hole 23 and part of the contour hole 22, and exposing the end face of the plastic 4 to finally obtain the functional hole 21 shown in fig. 9.

According to the processing method, the insert 1 is inserted into the contour hole 22 and is guided by the guide pillar 13 and the positioning hole 23 in a matching manner, so that a gap 3 is formed between the insert 1 and the contour hole 22, then the plastic 4 is injected between the insert 1 and the contour hole 22, the plastic 4 with uniform thickness can be quickly and stably formed, and after part of the outer part of the electronic product shell 2 is processed and removed, the functional hole 21 with stable structure and better strength can be formed.

In one embodiment, the processing method comprises the steps of:

a peripheral hole 221, an injection molding hole 222 and a positioning hole 23 are CNC-machined on the electronic product shell 2, wherein the peripheral hole 221 is close to the outside of the electronic product shell 2, the inner diameter of the peripheral hole 221 is larger than that of the injection molding hole 222, the injection molding hole 222 is arranged on the bottom wall of the peripheral hole 221, the injection molding hole 222 extends into the electronic product shell 2, the positioning hole 23 is close to the peripheral hole 221, and the positioning hole 23 and the peripheral hole 221 are located on the same side face of the electronic product shell 2;

the material blocking part 12 comprises a first material blocking column 121 and a second material blocking column 122, the material blocking part 12 is inserted into the contour hole 22 and is inserted into the positioning hole 23 through the guide column 13 for guiding, so that the second material blocking column 122 is inserted into the injection molding hole 222, the first material blocking column 121 is inserted into the peripheral hole 221, and the second material blocking column 122 and the injection molding hole 222 keep an equidistant gap 3;

injecting the plastic 4 between the second retaining post 122 and the injection molding hole 222, and after the plastic 4 is molded, extracting the insert 1 from the electronic product housing 2;

and (3) processing and removing part of the outer part of the electronic product shell 2, polishing and removing the positioning hole 23 and the peripheral hole 221, and exposing the injection molding hole 222 and the plastic 4 to finally obtain the functional hole 21 shown in fig. 9.

This kind of processing method can make the fashioned thickness of plastic 4 even, and efficiency is higher, can guarantee that electronic product casing 2 structure is more stable after polishing and getting rid of locating hole 23 and peripheral hole 221, and intensity is better. The processed functional hole 21 may be an earphone hole or a USB hole, and the electronic product housing 2 may specifically be a mobile phone housing.

In one embodiment, the processing method comprises the following steps:

positioning and installing the electronic product shell 2 with the contour hole 22 and the positioning hole 23 in a mold, then driving the insert 1 to be inserted into the contour hole 22 through a lead screw or an air cylinder, inserting the insert into the positioning hole 23 through the guide post 13 for guiding, inserting the material blocking part 12 into the contour hole 22, and keeping the gap 3 with equal spacing between the material blocking part 12 and the contour hole 22;

injecting plastic 4 between the material blocking part 12 and the contour hole 22 from the inside of the electronic product shell 2, filling the gap 3 with the plastic 4, and drawing out the insert 1 from the electronic product shell 2 after the plastic 4 is molded;

part of the exterior of the electronic product housing 2 is machined and removed, so that the positioning holes 23 and part of the contour holes 22 are polished, and the end surfaces of the plastic 4 are exposed, and finally the functional holes 21 shown in fig. 9 are obtained.

The automatic insert 1 can be driven to be inserted into the contour hole 22 automatically by arranging the driving device, so that the operation is convenient, and the efficiency is higher. It should be noted that, when the plastic 4 is injected between the material blocking member 12 and the contour hole 22, plastic members at other positions inside the electronic product housing 2 can be injection molded at the same time, so as to save the processing cost. It should be noted that the plastic parts at other positions inside the electronic product housing 2 are provided with a first concave surface and a second concave surface along the thickness direction of the electronic product housing 2. The electronic product shell 2 can be a middle frame of a mobile phone and a tablet personal computer, a display screen can be arranged on the first concave surface, a shell rear cover can be arranged on the second concave surface, and other electronic components such as a camera, a circuit board and the like are also arranged on the first concave surface or the second concave surface, so that the mobile phone or the tablet personal computer can be assembled. The functional hole 21 on the electronic product shell 2 specifically comprises a USB hole and an earphone hole, a plug connector is arranged in the electronic product shell 2 in an extending way from the inside of the electronic product shell to the USB hole and the earphone hole, the plug connector is electrically connected with a circuit board and is inserted into the earphone hole through an earphone plug, and the earphone plug is inserted into and electrically connected with the plug connector, so that the function of externally connecting an earphone is realized; the power line plug is inserted into the USB hole and is plugged and electrically connected with the plug connector, so that the power charging or data transmission function is realized.

In another embodiment, the electronic product housing 2 is a metal housing, and the processing method includes the following steps:

carrying out laser etching on the hole wall of the contour hole 22;

the insert 1 is inserted into the contour hole 22, the body 11 is completely attached to the outside of the electronic product shell 2, the guide post 13 is abutted to the bottom wall of the positioning hole 23, so that the material blocking part 12 is completely inserted into the contour hole 22, and the equally spaced gaps 3 are kept between the material blocking part 12 and the contour hole 22;

Through the body 11 clinging to the outer side of the electronic product and the abutting of the guide pillar 13 and the bottom wall of the positioning block, the material blocking part 12 can be ensured to be inserted in the contour hole 22 to be in place on the basis of forming stable guiding. Moreover, after laser etching is performed in the metal contour holes 22, the stability of the combination of the plastic 4 generated by injection molding can be better.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent should be subject to the appended claims.

Claims

1. A processing method of a functional hole of an electronic product shell is characterized in that the processing method comprises the following steps:

processing a contour hole and a positioning hole on the outer part of the electronic product shell;

the guide post is inserted into the positioning hole for guiding, so that the material blocking piece is inserted into the contour hole, and a gap with equal interval is formed between the material blocking piece and the contour hole;

injecting plastic between the material blocking part and the contour hole;

extracting the insert from the electronic product shell;

and processing and removing part of the outside of the electronic product shell, and exposing the end face of the plastic.

2. The machining method according to claim 1, wherein in the step of inserting the insert into the contour hole, the electronic product housing is first positioned in a mold, and then the insert is driven to be inserted into the contour hole by a driving device.

3. The machining method according to claim 1, wherein in the step of inserting the insert into the contour hole, the body completely abuts against the outside of the electronic product housing, and the guide pillar abuts against a bottom wall of the positioning hole, so that the stopper is completely inserted into the contour hole.

4. The method as claimed in claim 1, wherein in the step of injecting plastic, the plastic is injected from the inside of the housing of the electronic product to between the material blocking member and the contour hole, and the plastic fills the gap.

5. The manufacturing method of claim 1, wherein the electronic housing is a metal housing, and the hole wall of the contour hole is laser engraved before the step of inserting the insert into the contour hole.

6. The machining method according to claim 1, wherein there are two positioning holes, two positioning holes are respectively formed on both sides of the contour hole, two guide posts are respectively formed on both sides of the material blocking member, and the guide posts are matched with the positioning holes in a one-to-one correspondence.

7. The machining method according to claim 1, wherein the contour hole includes a peripheral hole formed by the outer portion being recessed inward, and an injection hole opened in a bottom wall of the peripheral hole and communicating with the inner portion; the material blocking piece comprises a first blocking column and a second blocking column, the first blocking column is arranged on the body in a protruding mode, the second blocking column is arranged on one side, away from the body, of the first blocking column in a protruding mode, the first blocking column is inserted into the peripheral hole, the second blocking column is inserted into the injection hole, the second blocking column is identical in appearance to the injection hole, and equidistant gaps are formed between the outer side face of the second blocking column and the inner side face of the injection hole.

8. The method of manufacturing of claim 7 wherein said first abutment completely blocks said peripheral hole to prevent plastic from flowing from said injection hole into said peripheral hole.

9. The manufacturing method as claimed in claim 8, wherein an inner diameter of the peripheral hole is larger than an inner diameter of the injection hole, a sectional area of the first retaining pillar is larger than a sectional area of the second retaining pillar, and the first retaining pillar and the peripheral hole have the same shape and size.

10. The method as claimed in claim 1, wherein the end of the guide post remote from the body is provided with a chamfer.