Forming mold and injection molding method of thin-shell plastic part

Abstract

The forming mold comprises an upper mold body and a lower mold body, an injection molding opening is formed in the top of the upper mold body, a mold cavity is formed in the top of the lower mold body, and an injection opening mounting assembly is arranged above the injection molding opening and used for connecting the injection molding opening with an injection opening of an injection molding machine. And a cooling mechanism is arranged in the lower mold and comprises a detachable cooling assembly, a left hose connecting assembly and a right hose connecting assembly, and the detachable cooling assembly can be detached from the lower mold. According to the forming mold of the thin-shell plastic part and the injection molding method, an injection port pipe on an injection molding machine can be rapidly connected with an injection port in an upper mold through the injection port mounting assembly, operation is convenient and rapid, the injection port and the injection port can be better attached after mounting, the influence of vibration generated by mold opening and mold closing is reduced, and the production efficiency is improved. The leakage condition is effectively avoided, and the reliability of the device in use is improved.

Description

Technical Field

[0001] The invention relates to the technical field of injection molds, in particular to a molding mold for a thin-shell plastic part and an injection molding method. Background Art

[0002] Plastic is a polymer organic material with resin as the main component, which is molded into a certain shape under a certain temperature and pressure and can maintain the given shape at room temperature. It is called a plastic part. Injection molds generally refer to injection molding. Injection molding is also called injection molding. It is a molding method that combines injection and molding. The advantages of the injection molding method are fast production speed, high efficiency, automated operation, a wide variety of colors, and shapes from simple to complex. Plastic parts need to be molded using injection molding molds.

[0003] Reference patent announcement number "CN221161405U" discloses an injection molding mold for plastic parts, wherein hydraulic rods are installed on the surface of the mold, a top mold is installed on the top of the two hydraulic rods, a convex rod is installed on the bottom of the top mold, a mold cavity is opened inside the bottom mold, a fixing groove is opened inside the water tank, a mounting door panel is installed inside the fixing groove, and a fan is installed inside the mounting door panel.

[0004] As shown in the above technology, a molding mold is used when making thin-shell plastic parts. The molding mold is usually composed of an upper mold and a lower mold. The upper mold is connected to the injection port of an injection molding machine. Most of the existing connection methods are to press the injection port against the injection port of the upper mold. However, when injecting thin-shell plastic parts, it is necessary to strictly control the pressure and injection speed, which will generate certain vibrations, and vibrations will also occur when opening and closing the mold, thereby reducing the degree of tightness between the injection port and the injection port, and then leakage occurs. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a molding die and an injection molding method for thin-shell plastic parts, which solve the problem of leakage caused by the low tightness between the upper mold and the injection port of the injection molding machine in the existing molding die for thin-shell plastic parts.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions: a molding die for a thin-shell plastic part comprises an upper die and a lower die, the top of the upper die is provided with an injection port, the top of the lower die is provided with a mold cavity, an injection port mounting assembly is provided above the injection port, and is used to connect the injection port with the injection port of an injection molding machine, a cooling mechanism is provided inside the lower die, the cooling mechanism comprises a detachable cooling assembly and left and right hose connection assemblies, the detachable cooling assembly can be removed from the lower die, the two hose connection assemblies are respectively installed at the water inlet and the water outlet of the detachable cooling assembly, and the hose connection assembly is used to connect an external cooling hose;

[0007] The injection port installation assembly includes an injection tube and a rotating ring. The injection tube is fixedly connected to the discharge port of the injection molding machine. The rotating ring is rotatably connected to the top of the upper mold. An L-shaped groove is provided inside the rotating ring. The surface of the injection tube is slidably connected to an injection port tube. The left and right sides of the injection port tube are fixedly connected to mounting blocks. The mounting blocks enter the L-shaped groove and rotate to fix the injection port tube so that the injection port is pressed tightly against the injection molding port.

[0008] Preferably, a fixing ring is fixedly connected to the surface of the injection tube, and a return spring is sleeved on the surface of the injection tube located between the fixing ring and the injection port tube, one end of the return spring is fixedly connected to the bottom of the fixing ring, and the other end of the return spring is fixedly connected to the top of the injection port tube.

[0009] Preferably, a circular groove is provided on the top of the upper mold, and a driving motor is fixedly connected to the bottom of the inner wall of the circular groove, a driving gear is fixedly connected to the output end of the driving motor, a section of gear teeth is fixedly connected to the surface of the rotating ring, and the driving gear meshes with the section of gear teeth for transmission.

[0010] Preferably, the detachable cooling assembly includes an annular groove opened on the top of the lower mold, and the annular groove surrounds the outside of the mold cavity, an upper protective frame and a lower protective frame are inserted in the annular groove, and the upper protective frame and the lower protective frame are snap-fitted and fastened by bolts, the dimensions of the upper protective frame, the lower protective frame and the annular groove are interference fit, cooling channels are opened inside the upper protective frame and the lower protective frame, and matching serrated grooves are opened on the inner side of the annular groove surface and the inner sides of the upper protective frame and the lower protective frame surfaces to increase the contact area.

[0011] Preferably, the hose connecting assembly includes a mounting tube, the surface of which is provided with threads, the mounting tube is threadedly connected to the opening after the upper protective frame and the lower protective frame are buckled through the threads, the other end of the mounting tube is fixedly connected to a round head tube, the surface of the mounting tube is slidably connected to a pressing sleeve, the inner surface of the pressing sleeve is fixedly connected to a pressing ring, and is used to press it to the outside of the cooling hose.

[0012] Preferably, the threaded part is threadedly connected to an adjusting bolt, and a surface sleeve of the mounting tube between the adjusting bolt and the pressing sleeve is provided with a limit spring, and the compression degree of the limit spring is changed by rotating the adjusting bolt to adjust the tightness of the fixing of the cold hose.

[0013] The present invention also discloses a method for injection molding of a thin shell plastic part, which specifically comprises the following steps:

[0014] Step 1: Mold installation: Use a crane to hoist the mold into the injection molding machine, connect the injection port in the upper mold with the injection port of the injection molding machine through the injection port fixing assembly, and fix the upper and lower molds;

[0015] Step 2: Raw material pretreatment: Select plastic particles and dry them at 100-120℃ for 4-6 hours to remove moisture to avoid bubbles or silver streaks during molding. Then heat the material to make it molten;

[0016] Step 3: Mold preparation: The surface roughness of the mold needs to be ≤0.1μm to ensure a smooth surface of the product. Mold temperature control is the key parameter: a cooling channel is formed through the channel in the detachable cooling component to achieve uniform heat dissipation, and the temperature difference is controlled within ±3℃ to reduce deformation.

[0017] Step 4: Injection and filling Multi-stage injection: First stage: set the pressure to 50-80MPa, set the injection speed to 200-300mm / s, fill 80%-90% of the cavity, second stage: set the pressure to 20-30MPa, injection speed to 50-100mm / s, complete the remaining filling to reduce internal stress.

[0018] Step 5: Pressure holding and cooling. The pressure holding is divided into three levels: 15MPa at level one, 10MPa at level two, and 5MPa at level three to compensate for shrinkage.

[0019] Step 6: Demolding: Use the demoulding mechanism to eject the formed thin shell plastic part from the mold.

[0020] Preferably, the cooling in step five is divided into two stages: firstly, rapid cooling to below the glass transition temperature at 15-20°C / s, and then natural cooling to the demoulding temperature.

[0021] Beneficial Effects

[0022] The present invention provides a molding die and injection molding method for a thin-shell plastic part. Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The molding mold and injection molding method of the thin-shell plastic part can quickly connect the injection port tube on the injection molding machine with the injection port in the upper mold through the injection port installation component. The operation is convenient and quick. After installation, the injection port and the injection port can be better fitted, reducing the influence of vibration generated by mold opening and closing, effectively avoiding leakage, and improving the reliability of the device during use.

[0024] 2. The molding mold and injection molding method of the thin-shell plastic part are provided with a detachable cooling component in the lower mold, and the cooling component can be opened, so that the cooling channel inside it can be easily inspected and repaired, thereby improving the convenience of the device when used.

[0025] 3. The molding mold and injection molding method of the thin-shell plastic part connect the external cooling water hose with the detachable cooling component through a hose connecting component. The hose connecting component is simple and quick to operate. When connecting the hose, only the compression sleeve needs to be pushed, and the cooling hose is stable after installation and is not easy to fall off. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the appearance of the present invention;

[0027] Figure 2 An exploded view of the present invention;

[0028] Figure 3 An exploded view of the lower mold and the detachable cooling assembly of the present invention;

[0029] Figure 4 It is a schematic diagram of the upper mold and injection port installation assembly of the present invention;

[0030] Figure 5 is a schematic diagram of a hose connection assembly of the present invention;

[0031] Figure 6 It is an exploded view of the hose connection assembly of the present invention.

[0032] In the figure: 1. upper mold; 2. lower mold; 3. injection port; 4. mold cavity; 5. injection port installation assembly; 51. injection tube; 52. rotating ring; 53. L-shaped groove; 54. injection port tube; 55. fixing ring; 56. reset spring; 57. mounting block; 58. gear teeth; 59. drive motor; 510. driving gear; 6. detachable cooling assembly; 61. annular groove; 62. upper protective frame; 63. lower protective frame; 64. cooling channel; 65. serrated groove; 7. hose connection assembly; 71. mounting tube; 72. thread; 73. round head tube; 74. pressing sleeve; 75. pressing ring; 76. adjusting bolt; 77. limit spring. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] See also Figure 1-Figure 6 The molding die of the thin shell plastic part provides three technical solutions:

[0035] The first embodiment comprises an upper mold 1 and a lower mold 2, an injection port 3 is provided on the top of the upper mold 1, a mold cavity 4 is provided on the top of the lower mold 2, an injection port mounting assembly 5 is provided above the injection port 3, and is used to connect the injection port 3 with the injection port of the injection molding machine, a cooling mechanism is provided inside the lower mold 2, and the cooling mechanism comprises a detachable cooling assembly 6 and two left and right hose connection assemblies 7, the detachable cooling assembly 6 can be removed from the lower mold 2, the two hose connection assemblies 7 are respectively installed at the water inlet and the water outlet of the detachable cooling assembly 6, and the hose connection assembly 7 is used to connect the external cooling hose;

[0036] The injection port installation assembly 5 includes an injection tube 51 and a rotating ring 52. The injection tube 51 is fixedly connected to the discharge port of the injection molding machine. The rotating ring 52 is rotatably connected to the top of the upper mold 1. An L-shaped groove 53 is provided inside the rotating ring 52. An injection port tube 54 is slidably connected to the surface of the injection tube 51. The left and right sides of the injection port tube 54 are fixedly connected to mounting blocks 57. The mounting blocks 57 enter the L-shaped groove 53 and rotate to fix the injection port tube 54 so that the injection port is tightly pressed against the injection port 3. The surface of the injection tube 51 is fixedly connected to the fixing ring 55 A return spring 56 is sleeved on the surface of the injection tube 51 between the fixed ring 55 and the injection port tube 54, one end of the return spring 56 is fixedly connected to the bottom of the fixed ring 55, and the other end of the return spring 56 is fixedly connected to the top of the injection port tube 54. A circular groove is opened on the top of the upper mold 1, and a driving motor 59 is fixedly connected to the bottom of the inner wall of the circular groove. A driving gear 510 is fixedly connected to the output end of the driving motor 59, and a section of gear teeth 58 is fixedly connected to the surface of the rotating ring 52, and the driving gear 510 is meshed with the section of gear teeth 58 for transmission.

[0037] The injection port installation assembly 5 can quickly connect the injection port tube on the injection molding machine with the injection port 3 in the upper mold. The operation is convenient and quick. After installation, the injection port and the injection port 3 can fit better, reducing the impact of vibration caused by mold opening and closing, effectively avoiding leakage, and improving the reliability of the device during use.

[0038] The second embodiment is mainly different from the first embodiment in that the detachable cooling assembly 6 includes an annular groove 61 opened on the top of the lower mold 2, and the annular groove 61 surrounds the outside of the mold cavity 4, an upper protective frame 62 and a lower protective frame 63 are inserted in the annular groove 61, and the upper protective frame 62 and the lower protective frame 63 are buckled and fastened by bolts, the dimensions of the upper protective frame 62 and the lower protective frame 63 and the annular groove 61 are interference fit, and cooling channels 64 are opened inside the upper protective frame 62 and the lower protective frame 63, and matching serrated grooves 65 are opened on the inner side of the surface of the annular groove 61 and the inner sides of the surfaces of the upper protective frame 62 and the lower protective frame 63 to increase the contact area.

[0039] By providing a detachable cooling assembly in the lower mold 2, the cooling assembly can be opened, thereby facilitating the inspection and maintenance of the cooling channel 64 inside the cooling assembly, thereby improving the convenience of the device when in use.

[0040] The third embodiment is mainly different from the second embodiment in that: the hose connecting assembly 7 includes a mounting tube 71, the surface of the mounting tube 71 is provided with a thread 72, the mounting tube 71 is threadedly connected to the opening after the upper protective frame 62 and the lower protective frame 63 are buckled through the thread 72, the other end of the mounting tube 71 is fixedly connected to a round head tube 73, the surface of the mounting tube 71 is slidably connected to a pressing sleeve 74, the inner surface of the pressing sleeve 74 is fixedly connected to a pressing ring 75 and is used to press it to the outside of the cooling hose, the thread 72 is threadedly connected to an adjusting bolt 76, and the surface of the mounting tube 71 between the adjusting bolt 76 and the pressing sleeve 74 is provided with a limit spring 77, and the adjusting bolt 76 is rotated to change the compression degree of the limit spring 77 to adjust the tightness of the cooling hose.

[0041] The external cooling water hose is connected to the detachable cooling assembly 6 through the hose connecting assembly 7. The hose connecting assembly 7 is simple and quick to operate. When connecting the hose, it is only necessary to push the pressing sleeve 74. In addition, the cooling hose is stable and not easy to fall off after installation.

[0042] The injection port 3 on the upper mold 1 is aligned with the injection port of the injection port tube 54. At this time, the injection port tube 54 is inserted into the interior of the rotating ring 52, and the mounting block 57 is in the vertical part of the L-shaped groove 53. The driving motor 59 is started to rotate the active gear 510. The active gear 510 rotates and matches with the gear 58 to rotate the rotating ring 52. The rotating ring 52 rotates and the mounting block 57 enters the horizontal arc part of the L-shaped groove 53. At this time, the installation of the injection port and the injection port is completed. Then, the pressing sleeve 74 is pushed to expose the round head tube 73, and the cooling hose is sleeved on the outside of the round head tube 73. The pressing sleeve 74 is loosened, and the pressing sleeve 74 is folded and reset under the action of the limit spring 77 to press the pressing ring 75 on the outside of the cooling hose. In addition, when the compression degree is low, the adjusting bolt 76 can be rotated to increase the compression degree of the limit spring 77.

[0043] The present invention also discloses a method for injection molding of a thin shell plastic part, which specifically comprises the following steps:

[0044] Step 1: Mold installation: Use a crane to hoist the mold into the injection molding machine, connect the injection port in the upper mold with the injection port of the injection molding machine through the injection port fixing assembly, and fix the upper and lower molds;

[0045] Step 2: Raw material pretreatment: Select plastic particles and dry them at 100-120℃ for 4-6 hours to remove moisture to avoid bubbles or silver streaks during molding. Then heat the material to make it molten;

[0046] Step 3: Mold preparation: The surface roughness of the mold needs to be ≤0.1μm to ensure a smooth surface of the product. Mold temperature control is the key parameter: a cooling channel is formed through the channel in the detachable cooling component to achieve uniform heat dissipation, and the temperature difference is controlled within ±3℃ to reduce deformation.

[0047] Step 4: Injection and filling Multi-stage injection: First stage: set the pressure to 50-80MPa, set the injection speed to 200-300mm / s, fill 80%-90% of the cavity, second stage: set the pressure to 20-30MPa, injection speed to 50-100mm / s, complete the remaining filling to reduce internal stress.

[0048] Step 5: Pressure holding and cooling. The pressure holding is divided into three levels: 15MPa at level one, 10MPa at level two, and 5MPa at level three to compensate for shrinkage.

[0049] Step 6: Demolding: Use the demoulding mechanism to eject the formed thin shell plastic part from the mold.

[0050] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0051] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A molding die for a thin-shell plastic part, comprising an upper mold (1) and a lower mold (2), characterized in that: The top of the upper mold (1) is provided with an injection port (3), the top of the lower mold (2) is provided with a mold cavity (4), an injection port mounting assembly (5) is arranged above the injection port (3) for connecting the injection port (3) with the injection port of an injection molding machine, a cooling mechanism is arranged inside the lower mold (2), the cooling mechanism comprises a detachable cooling assembly (6) and two left and right hose connection assemblies (7), the detachable cooling assembly (6) can be removed from the lower mold (2), the two hose connection assemblies (7) are respectively installed at the water inlet and water outlet of the detachable cooling assembly (6), and the hose connection assembly (7) is used to connect an external cooling hose; The injection port installation assembly (5) comprises an injection tube (51) and a rotating ring (52), wherein the injection tube (51) is fixedly connected to the discharge port of the injection molding machine, and the rotating ring (52) is rotatably connected to the top of the upper mold (1), and an L-shaped groove (53) is provided inside the rotating ring (52). An injection port tube (54) is slidably connected to the surface of the injection tube (51), and mounting blocks (57) are fixedly connected to the left and right sides of the injection port tube (54), and the mounting blocks (57) enter the L-shaped groove (53) and rotate so that the injection port tube (54) is fixed so that the injection port is pressed tightly against the injection molding port (3).

2. A forming mold for a thin shell plastic part according to claim 1, characterized in that: A fixing ring (55) is fixedly connected to the surface of the injection tube (51), and a return spring (56) is sleeved on the surface of the injection tube (51) located between the fixing ring (55) and the injection port tube (54), one end of the return spring (56) is fixedly connected to the bottom of the fixing ring (55), and the other end of the return spring (56) is fixedly connected to the top of the injection port tube (54).

3. The forming mold for a thin shell plastic part according to claim 1, characterized in that: A circular groove is formed on the top of the upper mold (1), and a driving motor (59) is fixedly connected to the bottom of the inner wall of the circular groove. A driving gear (510) is fixedly connected to the output end of the driving motor (59). A section of gear teeth (58) is fixedly connected to the surface of the rotating ring (52), and the driving gear (510) meshes with the section of gear teeth (58) for transmission.

4. The forming mold for a thin shell plastic part according to claim 1, characterized in that: The detachable cooling assembly (6) includes an annular groove (61) provided on the top of the lower mold (2), and the annular groove (61) surrounds the outside of the mold cavity (4), an upper protective frame (62) and a lower protective frame (63) are inserted in the middle of the annular groove (61), and the upper protective frame (62) and the lower protective frame (63) are buckled and fastened by bolts, and the dimensions of the upper protective frame (62) and the lower protective frame (63) and the annular groove (61) are interference fit, and cooling channels (64) are provided inside the upper protective frame (62) and the lower protective frame (63), and matching serrated grooves (65) are provided on the inner side of the surface of the annular groove (61) and the inner sides of the surfaces of the upper protective frame (62) and the lower protective frame (63) to increase the contact area.

5. The forming mold for a thin shell plastic part according to claim 1, characterized in that: The hose connection assembly (7) includes a mounting tube (71), the surface of which is provided with a thread (72), the mounting tube (71) is threadedly connected to the opening of the upper protective frame (62) and the lower protective frame (63) after being buckled together through the thread (72), the other end of the mounting tube (71) is fixedly connected to a round-headed tube (73), the surface of the mounting tube (71) is slidably connected to a pressing sleeve (74), the inner surface of the pressing sleeve (74) is fixedly connected to a pressing ring (75) for pressing onto the outside of the cooling hose.

6. The forming mold for a thin shell plastic part according to claim 5, characterized in that: The thread (72) is threadedly connected to an adjusting bolt (76); a limit spring (77) is sleeved on the surface of the mounting tube (71) between the adjusting bolt (76) and the pressing sleeve (74); the adjusting bolt (76) is rotated to change the compression degree of the limit spring (77) so as to adjust the tightness of the fixing of the cold hose.

7. The injection molding method of a thin shell plastic part according to claim 1, characterized in that: The specific steps include: Step 1: Mold installation: Use a crane to hoist the mold into the injection molding machine, connect the injection port in the upper mold with the injection port of the injection molding machine through the injection port fixing assembly, and fix the upper and lower molds; Step 2: Raw material pretreatment: Select plastic particles and dry them at 100-120℃ for 4-6 hours to remove moisture to avoid bubbles or silver streaks during molding. Then heat the material to make it molten; Step 3: Mold preparation: The surface roughness of the mold needs to be ≤0.1μm to ensure a smooth surface of the product. Mold temperature control is the key parameter: a cooling channel is formed through the channel in the detachable cooling component to achieve uniform heat dissipation, and the temperature difference is controlled within ±3℃ to reduce deformation. Step 4: Injection and filling Multi-stage injection: First stage: set the pressure to 50-80MPa, set the injection speed to 200-300mm / s, fill 80%-90% of the cavity, second stage: set the pressure to 20-30MPa, injection speed to 50-100mm / s, complete the remaining filling to reduce internal stress. Step 5: Pressure holding and cooling. The pressure holding is divided into three levels: 15MPa at level one, 10MPa at level two, and 5MPa at level three to compensate for shrinkage. Step 6: Demolding: Use the demoulding mechanism to eject the formed thin shell plastic part from the mold.

8. The injection molding method of a thin shell plastic part according to claim 7, characterized in that: The cooling in step 5 is divided into two stages: first, rapid cooling at 15-20° C. / s to below the glass transition temperature, and then natural cooling to the demoulding temperature.

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