A core-pulling structure of a two-color injection mold and a workpiece forming method

Abstract

The application relates to a core-pulling structure of a double-color injection mold and a workpiece forming method, and relates to the technical field of injection molds. The core-pulling structure of the double-color injection mold comprises a ring-shaped core-pulling piece, a first insert and a second insert arranged in the ring-shaped core-pulling piece, and a fixing block arranged outside a back mold. The first insert is detachably connected to the fixing block, and the ring-shaped core-pulling piece is sleeved outside the first insert and is in sliding connection with the first insert. A stepped fixing sleeve is arranged between the first insert and the ring-shaped core-pulling piece. An installation hole matched with the shape of the fixing sleeve is arranged on the inner side of the ring-shaped core-pulling piece. The outer side wall of the fixing sleeve is in abutment with the hole wall of the installation hole, and the inner side wall of the fixing sleeve is in abutment with the outer side wall of the first insert. A plurality of plug blocks are arranged around the outer side of the fixing sleeve. One end of the plug blocks is inserted into the fixing sleeve and is detachably connected with the first insert, and the other end of the plug blocks is in abutment with the inner side wall of the ring-shaped core-pulling piece. The first insert is positioned by the fixing sleeve and the plug blocks, and the effect of reducing flash is achieved.

Description

Technical Field

[0001] This application relates to the field of injection mold technology, and in particular to a core-pulling structure for a two-color injection mold and a workpiece forming method. Background Technology

[0002] Two-color injection molds are used to mold injection-molded parts with a structure that combines hard and soft plastic parts into one piece. The rear mold of a two-color injection mold has two rear mold cavities, and the front mold has two front mold cores. Each of the two rear mold cavities can mate with one of the two front mold cores. The injection molding process is divided into two parts. First, the hard plastic part is injection molded. After mold opening, the hard plastic part remains in the rear mold. The injection molding machine drives the rear mold to rotate 180° and then closes it with the front mold. The rear mold cavity containing the hard plastic part mates with the other front mold core to form a soft injection cavity. After the soft plastic is injected, it combines with the previously molded hard plastic part to form the two-color product part.

[0003] The rear mold cavity has a rear mold core that mates with the front mold core and a core-pulling structure inserted into the rear mold core. When molding soft plastic parts, a part of the soft plastic part is molded on the side of the front mold core, and another part of the soft plastic part is molded on the side of the rear mold core through the hard plastic part. The core-pulling structure mainly includes an insert and a core-pulling component arranged around the insert. The core-pulling component slides relative to the insert, so that the core-pulling component, the insert, and the hard plastic part are combined to form a space for molding the soft plastic part.

[0004] However, when the core-pulling component moves relative to the insert, the insert may move a certain distance along with the core-pulling component, and a gap may even be generated between the core-pulling component and the insert during the movement. This results in more flash when molding hard plastic parts, which puts a greater burden on the subsequent processing of the workpiece. Summary of the Invention

[0005] The purpose of this application is to provide a core-pulling structure and workpiece forming method for two-color injection molds that reduces flash formation.

[0006] Firstly, the core-pulling structure of a two-color injection mold provided in this application adopts the following technical solution:

[0007] A core-pulling structure for a two-color injection mold includes an annular core-pulling component, a first insert and a second insert placed inside the annular core-pulling component, and a fixing block placed outside the rear mold. The first insert is detachably connected to the fixing block, and the annular core-pulling component is sleeved outside the first insert and slidably connected to the first insert.

[0008] A stepped fixing sleeve is provided between the first insert and the annular core-pulling component. The inner side of the annular core-pulling component has an installation hole that matches the shape of the fixing sleeve. The outer side wall of the fixing sleeve abuts against the wall of the installation hole, and the inner side wall of the fixing sleeve abuts against the outer side wall of the first insert.

[0009] The outer side of the fixing sleeve is provided with a plurality of inserts, one end of which is inserted into the fixing sleeve and detachably connected to the first insert, and the other end of which abuts against the inner sidewall of the annular core-pulling component.

[0010] By adopting the above technical solution, during the movement of the annular core-pulling component relative to the first insert, it is constrained by the fixed sleeve and the insert block. The fixed sleeve and the first insert remain stationary, thus positioning the first insert and preventing the possibility of inaccurate positioning or poor sealing of the first insert during the movement of the annular core-pulling component. This reduces the formation of flash and improves the yield of the workpiece.

[0011] Optionally, the annular core-pulling component has a receiving groove for accommodating the second insert. The second insert is placed in the receiving groove and is detachably connected to the annular core-pulling component. The end of the second insert has a protruding bump for forming the workpiece, and the outer end of the protruding bump is surrounded by a protruding edge made of elastic material.

[0012] By adopting the above technical solution, the soft rubber can fit tightly with the protrusions and protruding edges on the second insert to reduce the formation of flash, and it is also easy to disengage from the soft rubber part when pulling the core.

[0013] Optionally, the insert includes a fixing post and a fixing bolt. The fixing post is inserted into the first insert. The mounting hole has an abutment groove that matches the shape of the fixing post. The remaining part of the fixing post extends out of the fixing sleeve and abuts against the groove wall. The fixing bolt passes through the fixing post and is threaded into the first insert.

[0014] By adopting the above technical solution, the first insert is fixed to the fixed sleeve by the fixed post and the fixed bolt. When the insert is inserted into the fixed sleeve, the peripheral side wall of the fixed post abuts against the groove wall of the insertion hole near the guide post, so as to prevent the fixed sleeve or the first insert from moving along with the annular core-pulling part when the annular core-pulling part moves towards the front model core.

[0015] Optionally, an elastic sealing block is provided in the abutment groove, one end of the sealing block abuts against the groove wall of the abutment groove, and the other end of the sealing block abuts against the outer wall of the fixing column.

[0016] By adopting the above technical solution, and by setting an elastic sealing block to seal the abutment groove area, the sealing block will expand in time during the process of the annular core-pulling part moving away from the rear mold relative to the first insert, filling the space formed between the insert block and the groove wall of the abutment groove when the annular core-pulling part moves, so as to further improve the sealing performance between the first insert and the fixed sleeve.

[0017] Optionally, the outer wall of the fixing sleeve is provided with a plurality of oiling grooves for lubrication.

[0018] By adopting the above technical solution, before the annular core-pulling component is fitted onto the fixed sleeve, lubricating oil can be injected into the oiling groove to reduce the friction between the fixed sleeve and the annular core-pulling component, thereby reducing the wear caused by the relative movement between the annular core-pulling component and the fixed sleeve.

[0019] Optionally, the first insert includes a first insert and a second insert, the first insert and the second insert are detachably connected, a limiting groove is formed on one side of the first insert and a limiting block extends on the groove wall of the limiting groove, and a mating hole matching the limiting block is formed on the second insert.

[0020] By adopting the above technical solution, the second insert can be replaced during the molding process, thereby changing the shape formed by the protruding end of the first insert to mold workpieces of different specifications.

[0021] Optionally, multiple guide posts are vertically arranged between the fixing block and the first insert. One end of each guide post is connected to the first insert, and the other end of each guide post has two symmetrically interlocking grooves along its own axis. A stepped hole with a stepped cross-section is provided on one side of the fixing block, and the guide post is inserted into the stepped hole and can move laterally relative to the fixing block.

[0022] By adopting the above technical solution, the wall surface of the stepped hole abuts against the wall surface of the engagement groove, so that the fixing sleeve and the first insert inside the fixing sleeve are fixed on the fixing block. When it is necessary to disengage the guide post from the fixing block, the guide post can be slid out of the stepped hole laterally.

[0023] Optionally, it also includes an ejection mechanism for moving the annular core-pulling component. The ejection mechanism includes a movable plate and multiple movable rods arranged around the movable plate. One end of each movable rod is connected to the movable plate, and the other end of each movable rod passes through the rear mold and the annular core-pulling component in sequence before being connected to the second insert.

[0024] By adopting the above technical solution, the second insert and the annular core-pulling component can be moved through the ejection mechanism, making the operation convenient.

[0025] Optionally, a slot for inserting the movable rod is provided on the outer side wall of the second insert in the vertical direction. The end of the movable rod is inserted into the slot and kept flush with the end face of the second insert. A forming block made of elastic material for forming the workpiece protrudes from the outer side of the movable rod.

[0026] By adopting the above technical solution, the movable rod can not only push the second insert to move, but the molding block on the movable rod can also cooperate with the second insert to form a molding surface for molding the workpiece. Moreover, the molding block is made of elastic material, which can better fit with the soft rubber part to reduce the formation of flash.

[0027] Secondly, the workpiece forming method provided in this application includes the following steps:

[0028] S1. The mold is closed so that the rear mold cavity fits with a front mold core. Then, hard plastic is injected into the mold cavity. After cooling and molding, a hard plastic part with multiple soft plastic holes is formed.

[0029] S2. Open the mold, leaving the hard plastic part in the rear mold. Then rotate the rear mold along with the hard plastic part 180 degrees so that the rear mold cavity containing the hard plastic part mates with another front mold core.

[0030] S3. Re-close the film and drive the lifting mechanism to make the annular core-pulling part and the second insert slide relative to the first insert to form a cavity for soft glue injection.

[0031] S4. Inject soft rubber into the new mold cavity to form a soft rubber part that is bonded to the hard rubber part;

[0032] S5. After cooling is complete, open the mold again, drive the lifting mechanism to retract the annular core-pulling part and the second insert, so that the molded workpiece is disengaged from the core-pulling mechanism and the workpiece is removed.

[0033] By adopting the above technical solution, the rear mold core cooperates with the front mold core to form multiple soft rubber holes on the hard rubber part during the molding of the hard rubber part. This allows the soft rubber to pass through the hard rubber part and enter evenly into the cavity formed by the annular core puller and the hard rubber part. This prevents the possibility of damage caused by excessive pressure during the soft rubber injection process, which could result in some soft rubber being damaged due to excessive force during molding in the cavity.

[0034] In summary, this application includes at least one of the following beneficial technical effects:

[0035] 1. In this application, a fixing sleeve and an insert block are provided to position the first insert. During the movement of the annular core-pulling component relative to the first insert, it is constrained by the fixing sleeve and the insert block. The fixing sleeve and the first insert remain stationary, thus positioning the first insert. This prevents the possibility of inaccurate positioning or poor sealing of the first insert during the movement of the annular core-pulling component, reduces the formation of flash, and improves the yield of the workpiece.

[0036] 2. By cooperating with the front mold core, multiple soft rubber holes are formed on the hard rubber part during molding, allowing the soft rubber to pass through the hard rubber part and enter the cavity formed by the annular core puller and the hard rubber part evenly. This prevents the possibility of damage caused by excessive pressure during the soft rubber injection process, which could result in some soft rubber being damaged due to excessive force during molding in the cavity.

[0037] 3. The second insert of this application has a raised edge surrounding the protrusion, and a molding block is provided on the end of the movable rod. Both the molding block and the raised edge are made of elastic material. When molding the soft rubber part, the soft rubber can fit tightly with the raised edge part and the molding block part on the second insert to reduce the formation of flash, and it is also easy to disengage from the soft rubber part when pulling the core. Attached Figure Description

[0038] Figure 1 This is a three-dimensional structural diagram of the core-pulling structure and the rear mold in Embodiment 1 of this application;

[0039] Figure 2 This is a three-dimensional structural diagram of the core-pulling structure in Embodiment 1 of this application;

[0040] Figure 3 This is a three-dimensional structural schematic diagram of the workpiece in Embodiment 1 of this application;

[0041] Figure 4 This is a schematic cross-sectional view of the core-pulling structure in Embodiment 1 of this application;

[0042] Figure 5 This is an exploded structural diagram of the first insert in Embodiment 1 of this application;

[0043] Figure 6 This is a cross-sectional view of the first insert and the fixing sleeve in Embodiment 1 of this application;

[0044] Figure 7 This is a three-dimensional structural schematic diagram of the annular core-pulling component in Embodiment 1 of this application;

[0045] Figure 8 This is a three-dimensional structural diagram of the fixing sleeve in Embodiment 1 of this application;

[0046] Figure 9 This is a cross-sectional view of the annular core-pulling component and the fixing sleeve in Embodiment 2 of this application.

[0047] In the diagram, 1. Annular core-pulling component; 11. Mounting hole; 12. Receiving groove; 13. Abutment groove; 2. First insert; 21. First insert block; 211. Limiting groove; 22. Second insert block; 221. Mating hole; 23. Limiting block; 24. Protruding part; 25. Groove; 3. Second insert; 31. Protrusion; 32. Protruding edge; 33. Slot; 4. Fixing block; 41. Stepped hole; 5. Fixing sleeve; 51. First fixing sleeve 511. Insertion hole; 52. Second fixing sleeve; 53. Oiling groove; 6. Insert block; 61. Fixing post; 62. Fixing bolt; 7. Sealing block; 8. Guide post; 81. Engaging groove; 9. Ejection mechanism; 91. Movable plate; 92. Movable rod; 93. Molding block; 10. Rear mold; 101. Rear mold cavity; 20. Rear mold core; 30. Workpiece; 301. Hard plastic part; 302. Soft plastic hole; 303. Soft plastic part. Detailed Implementation

[0048] The following is in conjunction with the appendix Figure 1 -Appendix Figure 9 This application will be described in further detail below.

[0049] Example 1:

[0050] Reference Figure 1 and Figure 2 The system includes a rear mold 10 and a two-color mold core-pulling structure. The rear mold 10 has two rear mold cavities 101, and a rear mold core 20 is provided in each of the two rear mold cavities 101. The core-pulling structure is placed at the rear mold 10 and cooperates with the rear mold core 20. It should be noted that the core-pulling structure and the rear mold core 20 are provided in both rear mold cavities 101. In this embodiment, the core-pulling structure and the rear mold core 20 in one of the rear mold cavities 101 are not shown.

[0051] Reference Figure 1 and Figure 3 When forming workpiece 30, the mold is closed, and then the hard plastic part 301 is formed in the mold. At this time, the mold is opened and the rear mold 10 is rotated 180 degrees so that the thick film cavity after forming the hard plastic part 301 matches another front mold core. Then, plastic is injected to form a soft plastic part 303 that is combined with the hard plastic part 301, and workpiece 30 is formed.

[0052] Furthermore, during the molding of the hard plastic part 301, under the action of the front mold core and the rear mold core 20, multiple soft plastic holes 302 for soft plastic to pass through will be formed on the hard plastic part 301 to prevent the plastic from accumulating excessive pressure during the injection process, so as to prevent the possibility of damage to the weak parts of the soft plastic part 303 when molding the soft plastic part 303 that is combined with the hard plastic part 301.

[0053] Reference Figure 2 and Figure 4The core-pulling structure includes an annular core-pulling component 1, a first insert 2 and a second insert 3 placed inside the annular core-pulling component 1, and a fixing block 4 placed outside the rear mold 10. The first insert 2 is detachably connected to the fixing block 4, the second insert 3 is fixed inside the annular core-pulling component 1, and the annular core-pulling component 1 is sleeved outside the first insert 2 and slidably connected to the first insert 2.

[0054] Furthermore, the annular core-pulling member 1 has a receiving groove 12 for accommodating the second insert 3 on the end away from the thick film. The second insert 3 is placed in the receiving groove 12 and is detachably connected to the annular core-pulling member 1 by bolts, so that the second insert 3 and the annular core-pulling member 1 move synchronously. The end of the second insert 3 is provided with a protrusion 31 for forming the workpiece 30. The outer end of the protrusion 31 is surrounded by a protruding edge 32 made of elastic material.

[0055] In this embodiment, silicone rubber is selected as the elastic material. In other embodiments, an elastic material with similar properties to silicone rubber can also be selected. When molding the soft rubber part 303, the soft rubber can fit tightly with the protrusion 31 and the protruding edge 32 on the second insert 3 to reduce the formation of flash, and it is also easy to disengage from the soft rubber part 303 when pulling the core.

[0056] Reference Figure 1 and Figure 2 It also includes an ejection mechanism 9 for pushing the annular core-pulling component 1 to move. The ejection mechanism 9 includes a movable plate 91 and multiple movable rods 92 arranged around the movable plate 91. In this embodiment, four movable rods 92 are provided. One end of each of the four movable rods 92 is detachably connected to the movable plate 91 by screws. The other end of the movable rods 92 passes through the rear mold 10 and the annular core-pulling component 1 in sequence and is detachably connected to the second insert 3 by bolts.

[0057] Specifically, in combination Figure 4 The outer side wall of the second insert 22 is provided with a slot 33 for inserting the movable rod 92 in the vertical direction. The end of the movable rod 92 is inserted into the slot 33 and is flush with the end face of the second insert 22 to form a forming surface for forming the workpiece 30. In addition, a forming block 93 made of elastic material for forming the workpiece 30 is provided on the outer side of the movable rod 92. In this embodiment, the forming block 93 is made of the same material as the protruding edge 32.

[0058] When it is necessary to move the annular core-pulling component 1 and the second insert 3 relative to the first insert 2, the movable plate 91 is pushed and pulled, causing the movable rod 92 to drive the second insert 3 to move. Since the second insert 3 is fixed inside the annular core-pulling component 1, the annular core-pulling component 1 and the second insert 3 move synchronously. It should be noted that in this embodiment, the power to push and pull the movable plate 91 is provided by a motor.

[0059] Reference Figure 4 and Figure 5 The first insert 2 has a protruding portion 24 at its end. The protruding portion 24 is specifically configured according to the shape of the workpiece 30 to be formed. In this embodiment, multiple protruding portions 24 are provided. Adjacent protruding portions 24 form a groove 25 with corners, which is used to form the reinforcing rib portion of the workpiece 30.

[0060] Furthermore, the first insert 2 includes a first insert 21 and a second insert 22. The first insert 21 and the second insert 22 are detachably connected. A limiting groove 211 is provided on one side of the first insert 21, and a limiting block 23 extends from the groove wall of the limiting groove 211. A mating hole 221 matching the limiting block 23 is provided on the second insert 22.

[0061] When the second insert 22 is installed on the first insert 21, the mating hole 221 on the second insert 22 is aligned with the limiting block 23 on the first insert 21. Then, the first insert 21 and the second insert 22 are detachably connected by bolts. The ends of the first insert 21 and the second insert 22 both have protruding portions 24, and the two sets of protruding portions 24 are smoothly transitioned. When forming the workpiece 30, the second insert 22 can also be replaced to change the shape formed by the protruding end of the first insert 2, so as to form workpieces 30 of different specifications.

[0062] Reference Figure 4 and Figure 6 In order to secure the first insert 2, a fixing sleeve 5 is provided around the outer periphery of the first insert 2. The fixing sleeve 5 is stepped and is placed between the first insert 2 and the annular core puller 1. The outer side wall of the fixing sleeve 5 abuts against the inner side wall of the annular core puller 1, and the inner side wall of the fixing sleeve 5 abuts against the outer side wall of the first insert 2.

[0063] When the annular core puller 1 slides relative to the first insert 2, the inner peripheral sidewall of the annular core puller 1 abuts against the outer peripheral sidewall of the fixing sleeve 5, preventing the plastic from entering the gap between the annular core puller 1 and the first insert 2 after being injected into the mold, thus preventing flash from forming.

[0064] Furthermore, combined Figure 7 and Figure 8 When the annular core puller 1 slides, in order to prevent the fixing sleeve 5 from sliding relative to the first insert 2, a plurality of insert blocks 6 are arranged around the outer side of the fixing sleeve 5. Specifically, the fixing sleeve 5 mainly includes a first fixing sleeve 51 and a second fixing sleeve 52. The first fixing sleeve 51 and the second fixing sleeve 52 are integrally formed. The size of the first fixing sleeve 51 is smaller than that of the second fixing sleeve 52, so that the outer surfaces of the first fixing sleeve 51 and the second fixing sleeve 52 are combined to form a stepped shape.

[0065] The outer side of the first fixing sleeve 51 is provided with a plurality of insertion holes 511 for inserting the insert 6. The insert 6 is inserted into the first fixing sleeve 51 through the insertion holes 511 and is detachably connected to the first insert 21. Specifically, the insert 6 includes a fixing post 61 and a fixing bolt 62. Part of the fixing post 61 extends into the first insert 21, and the remaining part of the fixing post 61 extends out of the first fixing sleeve 51 and cooperates with the annular core puller 1. Correspondingly, the inner sidewall of the annular core puller 1 is provided with an abutment groove 13 that matches the shape of the fixing post 61. The end of the fixing post 61 abuts against the groove wall of the abutment groove 13, while the fixing bolt 62 passes through the fixing post 61 and is threadedly engaged with the first insert 21.

[0066] In addition, the diameter of the insertion hole 511 is larger than the outer diameter of the fixing post 61 so that the insertion block 6 can be inserted from the insertion hole 511. When the insertion block 6 is inserted into the first fixing sleeve 51, the peripheral sidewall of the fixing post 61 abuts against the groove wall of the insertion hole 511 near the guide post 8 to prevent the fixing sleeve 5 or the first insert 2 from moving along with the annular core puller 1 when it moves toward the front model core.

[0067] Furthermore, referring to Figure 2 and Figure 4 To prevent the annular core puller 1 from moving the fixing sleeve 5 when it retracts to the initial position, in this embodiment, multiple guide posts 8 are vertically arranged between the fixing block 4 and the first insert 21. In this embodiment, there are two guide posts 8, one end of which is connected to the first insert 21, and the other end of which is symmetrically provided with two engagement grooves 81 along its own axis. A stepped hole 41 with a stepped cross-section is provided on one side of the fixing block 4. When the guide post 8 is inserted into the fixing block 4, the wall surface of the stepped hole 41 abuts against the wall surface of the engagement groove 81. When it is necessary to disengage the guide post 8 from the fixing block 4, the guide post 8 can be slid laterally out of the stepped hole 41.

[0068] Reference Figure 6 The guide post 8 is connected to the first insert 21 at one end, and a meshing groove 81 is also provided. Correspondingly, the second fixing sleeve 52 is provided with a stepped hole 41 that matches the meshing groove 81. The guide post 8 is inserted into the stepped hole 41 and is detachably connected to the second fixing sleeve 52 by bolts, so that the position of the second fixing sleeve 52 is fixed by the fixing block 4. The bolt passes through the second fixing sleeve 52 and its end abuts against the side wall of the first insert 21 to further constrain the first insert 21.

[0069] In addition, combined Figure 8The outer wall of the second fixed sleeve 52 is provided with a plurality of oiling grooves 53 for lubrication. Before the annular core puller 1 is fitted onto the fixed sleeve 5, lubricating oil can be injected into the oiling grooves 53 to reduce the friction between the fixed sleeve 5 and the annular core puller 1 and reduce the wear caused by the relative movement between the annular core puller 1 and the fixed sleeve 5.

[0070] The implementation principle of Embodiment 1 of this application is as follows: After the hard plastic part 301 is molded, the mold is opened, and the rear mold 10 and the hard plastic part 301 in the mold cavity are rotated together, so that the mold cavity is engaged with another front mold core. After the mold is closed, the ejector mechanism is pushed, and the ejector mechanism pushes the second insert 3, so that the second insert 3 and the annular core-pulling part 1 move together in a direction away from the rear mold 10 relative to the first insert 2. A cavity is formed between the annular core-pulling part 1 and the first insert 2 for the soft plastic part 303 to enter, so that the soft plastic can be injected.

[0071] During the movement of the annular core-pulling component 1 relative to the first insert 2, it is constrained by the fixed sleeve 5 and the insert block 6. The fixed sleeve 5 and the first insert 2 remain stationary, forming a positioning of the first insert 2. This prevents the possibility of the first insert 2 being inaccurate in position or not being properly sealed during the movement of the annular core-pulling component 1, reduces the formation of flash, and improves the yield of the workpiece 30.

[0072] Example 2:

[0073] Reference Figure 9 The difference between this embodiment 2 and embodiment 1 is that an elastic sealing block 7 is provided in the abutment groove 13. The sealing block 7 is detachably connected to the side wall of the fixing column 61 by bolts. One end of the sealing block 7 abuts against the groove wall of the abutment groove 13, and the other end of the sealing block 7 extends into the insertion groove and abuts against the outer side wall of the first insert 21 and the fixing column 61 respectively.

[0074] The implementation principle of Embodiment 2 of this application is as follows: by setting an elastic sealing block 7 to block the area of ​​the abutment groove 13, during the process of the annular core puller 1 moving away from the rear mold 10 relative to the first insert 2, the sealing block 7 will stretch in time to fill the space formed between the insert block 6 and the groove wall of the abutment groove 13 when the annular core puller 1 moves, so as to further improve the sealing between the first insert 2 and the fixed sleeve 5.

[0075] Example 3:

[0076] The difference between this embodiment 3 and embodiment 2 is that it also discloses a molding process for workpiece 30 based on the above-mentioned injection-molded annular soft rubber core-pulling structure, including the following steps:

[0077] S1. The mold is closed so that the rear mold cavity 101 fits with a front mold core. Then, hard plastic is injected into the mold cavity. After cooling and molding, a hard plastic part 301 with multiple soft plastic holes 302 is formed.

[0078] S2. Open the mold, leaving the hard plastic part 301 inside the rear mold 10. Then rotate the rear mold 10 together with the hard plastic part 301 by 180 degrees, so that the rear mold cavity 101 containing the hard plastic part 301 mates with another front mold core.

[0079] S3. Re-close the film and drive the lifting mechanism to make the annular core-pulling part 1 and the second insert 3 slide relative to the first insert 2 to form a cavity for soft glue injection.

[0080] S4. Inject soft rubber into the new mold cavity to form a soft rubber part 303 that is bonded to the hard rubber part 301;

[0081] S5. After cooling is complete, open the mold again and drive the lifting mechanism to retract the annular core-pulling part 1 and the second insert 3, so that the formed workpiece 30 is disengaged from the core-pulling mechanism and the workpiece 30 is removed.

[0082] The implementation principle of Embodiment 3 of this application is as follows: by cooperating with the front mold core through the rear mold core 20, multiple soft rubber holes 302 for soft rubber flow are formed on the hard rubber part 301 when molding the hard rubber part 301, so that the soft rubber can pass through the hard rubber part 30 and enter the cavity formed by the annular core puller 1 and the hard rubber part 301 evenly, preventing the possibility that the pressure is too large during the soft rubber injection process, which may cause some soft rubber to be damaged due to excessive force when molding in the cavity.

[0083] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A core-pulling structure for a two-color injection mold, characterized in that, It includes an annular core-pulling component (1), a first insert (2) and a second insert (3) placed inside the annular core-pulling component (1), and a fixing block (4) placed outside the rear mold (10). The first insert (2) is detachably connected to the fixing block (4), and the annular core-pulling component (1) is sleeved on the outside of the first insert (2) and slidably connected to the first insert (2). A stepped fixing sleeve (5) is provided between the first insert (2) and the annular core puller (1). The inner side of the annular core puller (1) is provided with an installation hole (11) that matches the shape of the fixing sleeve (5). The outer side wall of the fixing sleeve (5) abuts against the hole wall of the installation hole (11), and the inner side wall of the fixing sleeve (5) abuts against the outer side wall of the first insert (2). The outer side of the fixing sleeve (5) is provided with a plurality of inserts (6). One end of the insert (6) is inserted into the fixing sleeve (5) and detachably connected to the first insert (2). The other end of the insert (6) abuts against the inner sidewall of the annular core puller (1).

2. The core-pulling structure of a two-color injection mold according to claim 1, characterized in that, The annular core-pulling component (1) has a receiving groove (12) for accommodating the second insert (3). The second insert (3) is placed in the receiving groove (12) and is detachably connected to the annular core-pulling component (1). The end of the second insert (3) is provided with a protrusion (31) for forming a workpiece (30). The outer end of the protrusion (31) is surrounded by a protruding edge (32) made of elastic material.

3. The core-pulling structure of a two-color injection mold according to claim 1, characterized in that, The insert (6) includes a fixing post (61) and a fixing bolt (62). The fixing post (61) is partially inserted into the first insert (2). The mounting hole (11) has an abutment groove (13) that matches the shape of the fixing post (61) on its wall. The remaining part of the fixing post (61) extends out of the fixing sleeve (5) and abuts against the groove wall of the abutment groove (13). The fixing bolt (62) passes through the fixing post (61) and is threadedly engaged with the first insert (2).

4. The core-pulling structure of a two-color injection mold according to claim 3, characterized in that, An elastic sealing block (7) is provided in the abutment groove (13). One end of the sealing block (7) abuts against the groove wall of the abutment groove (13), and the other end of the sealing block (7) abuts against the outer wall of the fixing column (61).

5. The core-pulling structure of a two-color injection mold according to claim 1, characterized in that, The outer wall of the fixed sleeve (5) is provided with a plurality of oiling grooves (53) for lubrication.

6. The core-pulling structure of a two-color injection mold according to claim 1, characterized in that, The first insert (2) includes a first insert (21) and a second insert (22). The first insert (21) and the second insert (22) are detachably connected. A limiting groove (211) is provided on one side of the first insert (21), and a limiting block (23) extends on the groove wall of the limiting groove (211). A mating hole (221) matching the limiting block (23) is provided on the second insert (22).

7. The core-pulling structure of a two-color injection mold according to claim 6, characterized in that, Multiple guide posts (8) are vertically arranged between the fixing block (4) and the first insert (21). One end of the guide post (8) is connected to the first insert (21), and the other end of the guide post (8) is symmetrically provided with two interlocking grooves (81) along its own axis. A stepped hole (41) with a stepped cross-section is provided on one side of the fixing block (4). The guide post (8) is inserted into the stepped hole (41) and can move laterally relative to the fixing block (4).

8. The core-pulling structure of a two-color injection mold according to claim 1, characterized in that, It also includes an ejection mechanism (9) for pushing the annular core-pulling component (1) to move. The ejection mechanism (9) includes a movable plate (91) and multiple movable rods (92) arranged around the movable plate (91). One end of the movable rod (92) is connected to the movable plate (91), and the other end of the movable rod (92) passes through the rear mold (10) and the annular core-pulling component (1) in sequence and is connected to the second insert (3).

9. The core-pulling structure of a two-color injection mold according to claim 8, characterized in that, The second insert (3) has a slot (33) for inserting the movable rod (92) in the vertical direction on the outer side wall. The end of the movable rod (92) is inserted into the slot (33) and is flush with the end face of the second insert (3). A forming block (93) made of elastic material for forming the workpiece (30) is protruding from the outer side of the movable rod (92).

10. A workpiece-type process based on the core-pulling structure of claim 8, characterized in that, Includes the following steps: S1. The mold is closed so that the rear mold cavity (101) fits with a front mold core. Then, hard plastic is injected into the mold cavity. After cooling and molding, a hard plastic part (301) with multiple soft plastic holes (302) is formed. S2. Open the mold, leaving the hard plastic part (301) inside the rear mold (10). Then rotate the rear mold (10) together with the hard plastic part (301) 180 degrees so that the rear mold cavity (101) containing the hard plastic part (301) can mate with another front mold core. S3. Close the mold again and drive the ejection mechanism to make the annular core puller (1) and the second insert (3) slide relative to the first insert (2) to form a cavity for soft glue injection. S4. Inject soft rubber into the new mold cavity to form a soft rubber part (303) that is bonded to the hard rubber part (301). S5. After cooling is complete, open the mold again and drive the ejection mechanism to retract the annular core puller (1) and the second insert (3) so that the molded workpiece (30) is disengaged from the core puller structure and the workpiece (30) is removed.

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