Layered injection molding lens mold structure

Abstract

According to the layered injection molding lens mold structure, the function of adjusting injection molding balance in the secondary injection molding process is added, meanwhile, excessive structures do not need to be additionally arranged, and use of raw materials is reduced. The secondary injection mold structurally comprises a secondary injection mold body, when a product core is placed in the secondary injection mold body, a certain gap is formed between the upper portion of the product core and the secondary injection mold body, a certain gap is formed between the lower portion of the product core and the secondary injection mold body, an upper-layer cavity and a lower-layer cavity are formed, and pouring gate aggregate of the product core subjected to primary injection molding is reserved; when the product core is placed in the secondary injection mold, the pouring gate aggregate is located in the containing groove, a certain gap is formed between the upper portion and the secondary injection mold, a certain gap is formed between the lower portion of the pouring gate aggregate and the secondary injection mold, an upper-layer overflow cavity and a lower-layer overflow cavity are formed, the upper-layer overflow cavity is communicated with the upper-layer mold cavity, and the lower-layer overflow cavity is communicated with the lower-layer mold cavity.

Description

Technical Field

[0001] The invention relates to the technical field of layered injection molding, in particular to a lens mold structure for layered injection molding. Background Art

[0002] Layered injection molding generally uses the first mold to perform the first injection molding to form a part of the product, and then takes it out and places it into the secondary injection mold for the second injection molding to form the complete product.

[0003] The layered injection molding method used in the past, such as the patent with publication number CN108656446A, discloses a fixed structure and mold for a layered injection molding core, which requires processing the product core (core) and the fixed structure together during the first injection molding. The fixed structure extends outward from the side of the product core and is used to support the product core during the second injection molding so that the product core is suspended in the air.

[0004] Since the existence of the fixed structure will waste a lot of raw materials and increase the mold structure, in order to address this problem, the patent with publication number CN113635519A discloses a mold structure for thick-walled products. During the second injection molding, a circle of positioning ribs at the edge of the product core itself is used for positioning support, so that there is no need to add additional positioning structure for fixation and positioning. At the same time, in the above scheme, the material flow of the upper and lower layers of the product will be completely separated during the second injection molding and will not intersect at the end of the injection molding. This places high demands on the balance of layered injection molding. Once the upper or lower layer is glued too quickly, it will cause pressure imbalance between the upper and lower layers and generate stress on the product core, thereby causing injection molding cracking. Summary of the Invention

[0005] In response to the problem of high balance requirements in layered injection molding, the present invention provides a lens mold structure for layered injection molding, which adds the function of adjusting the injection balance during the secondary injection molding process, while not requiring additional excessive structures and reducing the use of raw materials.

[0006] Its technical solution is as follows: a layered injection lens mold structure, which includes a secondary injection mold, and a secondary injection mold is provided on the secondary injection mold for performing a second injection on the product core obtained by the first injection. When the product core is placed in the secondary injection mold, there is a certain gap between the upper and lower parts of the product core and the secondary injection mold, and an upper cavity and a lower cavity are formed respectively. The upper cavity and the lower cavity are respectively connected to the glue inlet of the secondary injection mold. It is characterized in that: the product core after the first injection retains its gate condensate, and a receiving groove is provided in the secondary injection mold. When the product core is placed in the secondary injection mold, the gate condensate is located in the receiving groove, and there is a certain gap between the upper and lower parts of the gate condensate and the secondary injection mold, and an upper overflow cavity and a lower overflow cavity are formed respectively. The upper overflow cavity is connected to the upper cavity, and the lower overflow cavity is connected to the lower cavity.

[0007] Furthermore, the glue inlet of the secondary injection mold is located on the side opposite to the side where the gate condensate is located.

[0008] Furthermore, gaps are reserved around the secondary injection molding cavity to accommodate the deformation of the product core, so as to facilitate the placement of the product core into the secondary injection molding cavity.

[0009] Furthermore, the reserved gap width is 0.1-2 mm.

[0010] Furthermore, the product core contacts the secondary injection mold through a side edge, and the side edge has a certain draft angle.

[0011] Furthermore, the distance between the gate condensate and the secondary injection mold is 0.1-2 mm.

[0012] Furthermore, the cross-sectional shapes of the upper overflow cavity and the lower overflow cavity are rectangular, trapezoidal or arc-shaped.

[0013] Furthermore, the glue inlet is a rectangular notch provided in the middle position of one side of the product core, and the glue inlet is communicated with the glue inlet channel.

[0014] Furthermore, the secondary injection molding cavity is provided with at least two secondary injection molding cavities arranged in a mirror image.

[0015] Beneficial effects: During the secondary injection molding, the glue enters the mold through the glue inlet of the secondary injection mold and enters the upper cavity and lower cavity above and below the product core respectively. Even if the upper or lower layer glue enters too quickly, it can overflow the cavity through the upper overflow cavity or the lower overflow cavity, thereby avoiding the stress on the product core caused by the imbalance of pressure between the upper and lower layers and causing injection molding cracking; at the same time, the above-mentioned balance structure utilizes the gate condensate produced by the first injection molding, and only needs to open a receiving groove on the secondary injection mold, without the need to add too much additional structure, reducing the use of raw materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the structure of the primary injection mold and the secondary injection mold;

[0017] Figure 2 This is a schematic diagram of the product core structure;

[0018] Figure 3 This is a cross-sectional view of the product obtained by secondary injection molding;

[0019] Figure 4 Schematic diagram of the glue feeding distribution during the secondary injection molding process. DETAILED DESCRIPTION

[0020] like Figure 1 The lens mold structure of layered injection molding shown in the figure includes a primary injection mold 1 and a secondary injection mold 2. The secondary injection mold 2 is provided with a secondary injection cavity for performing a second injection molding on the product core 3 obtained by the first injection molding. Preferably, a secondary injection mold 2 is provided with two or more mirror-image-distributed secondary injection cavities, which can realize one-out-two, one-out-four and other production. This arrangement can avoid the problem that the product core 3 cannot be placed in the mold for production due to size differences caused by shrinkage. When the product core 3 is placed in the secondary injection mold 2, there is a certain gap between the upper and lower parts of the product core 3 and the secondary injection mold 2, and an upper cavity and a lower cavity are formed respectively (formed by injecting glue into the upper cavity). Figure 3 、 4 The A shown is formed by injecting glue into the lower cavity Figure 3 、 4 As shown in B), the upper cavity and the lower cavity are respectively connected to the glue inlet 201 of the secondary injection mold. As a preference, the glue inlet 201 is a rectangular notch set in the middle position of one side of the product core 3 and chamfered. The glue inlet 201 is connected to the glue inlet channel and divides the material flow into two and introduces it into the upper and lower cavities. Figure 2The product core 3 after the first injection molding retains its gate condensate 301. Preferably, the gate condensate 301 is located in the middle of one side of the product core 3, so that the product core 3 can avoid warping when cooling. The glue inlet 201 of the secondary injection mold is preferably located on the opposite side of the side where the gate condensate 301 is located, so that when the secondary injection molding is performed, the material flow flows from one side of the product core 3 to the other side. A receiving groove is provided in the secondary injection mold 2. When the product core 3 is placed in the secondary injection mold 2, the gate condensate 301 is located in the receiving groove, and There is a certain gap between the gate condensate 301 and the secondary injection mold 2 at least above and below, and an upper overflow cavity and a lower overflow cavity can be formed. Preferably, the spacing between the gate condensate 301 and the secondary injection mold 2 is 0.1-2 mm, and the cross-sectional shape of the upper overflow cavity and the lower overflow cavity is rectangular, trapezoidal or arc-shaped; the upper overflow cavity is connected to the upper cavity, and the lower overflow cavity is connected to the lower cavity, thereby forming a gap channel for the secondary injection material flow to pass through, so as to reduce the pressure and internal stress in the cavity.

[0021] Through the above structure, the gate condensate 301 obtained by the primary injection molding is used to set a receiving groove corresponding to the gate condensate 301 on the secondary injection mold 2, and the gate condensate 301 is used to separate the receiving groove into an upper overflow cavity located above and a lower overflow cavity located below. In this way, when the secondary injection mold 2 is filled with glue, even if the glue is not fed synchronously into the upper cavity and the lower cavity, the material flow that fills the cavity first can still be as follows. Figure 3 、 Figure 4 As shown, it enters the overflow cavity to form Figure 3 、 Figure 4 The condensate at C or D in the middle will not affect the quality of the product due to unbalanced injection molding, thereby greatly reducing the balance requirement for layered injection molding compared to the existing structure, and is more convenient to use. Finally, after the injection molding is completed, the condensed material flow in the overflow cavity can be removed together with the gate condensate 301.

[0022] At the same time, in order to further facilitate use, the existing mold structure needs to rely on a circle of positioning ribs on the edge of the product core 3 for positioning support, which requires its size to correspond to the mold size of the second injection. In addition, the deformation of the product core 3 during the process of being taken out of the primary injection mold 1 and then placed in the secondary injection mold 2 after the first injection makes it inconvenient to place the product core into the mold of the second injection. For this reason, in this solution, a gap is reserved around the secondary injection cavity to accommodate the deformation of the product core 3, which is used to ensure that the product core 3 is smoothly placed into the secondary injection cavity when the product core 3 is placed into the secondary injection cavity. Preferably, the reserved gap width is 0.1-2mm. At the same time, the glue inlet 201 and the gate condensate 301 are respectively located on both sides of the product core, and can be arranged in a centrally symmetrical or axially symmetrical arrangement. The other two sides of the product core 3 serve as the force-bearing surfaces of the upper and lower clamping molds of the secondary injection mold, for example. Figure 2As shown, the two short sides of the product core 3 in the thickness direction serve as the force-bearing surfaces of the product core 3 in the upper and lower molds in the secondary injection mold 2. Through the force on the short sides, the product is pre-pressed in the cavity. After being subjected to the injection pressure, the product core can remain stable in the thickness direction. Since it only relies on the two short sides to bear the force, it is easy to place the product core 3 into the secondary injection mold 2.

[0023] In addition, the product core 3 contacts the secondary injection mold through the side and the side has a certain draft angle, preferably 5 degrees, so that the product core 3 can be placed more smoothly into the cavity of the secondary injection mold 2 and can be decomposed to the side after being subjected to the clamping force, making the product core more stable in the mold cavity.

[0024] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by anyone familiar with the art within the technical scope disclosed by the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A layered injection molding lens mold structure, comprising a secondary injection mold, the secondary injection mold having a secondary injection cavity for performing a second injection molding on a product core obtained by the first injection molding process. When the product core is placed in the secondary injection mold, a certain gap is formed between the upper and lower parts of the product core and the secondary injection mold, respectively, forming an upper cavity and a lower cavity. The upper cavity and the lower cavity are respectively connected to the glue inlet of the secondary injection mold. The structure is characterized by: The product core that completes the first injection molding retains its gate condensate, and a receiving groove is provided in the secondary injection mold. When the product core is placed in the secondary injection mold, the gate condensate is located in the receiving groove, and there is a certain gap between the upper and lower parts of the gate condensate and the secondary injection mold, respectively, and an upper overflow cavity and a lower overflow cavity are formed respectively, the upper overflow cavity is connected to the upper cavity, and the lower overflow cavity is connected to the lower cavity.

2. The lens mold structure for layered injection molding according to claim 1, characterized in that: The glue inlet of the secondary injection mold is located on the side opposite to the side where the gate condensate is located.

3. The layered injection molded lens mold structure according to claim 1, characterized in that: A gap is reserved around the secondary injection molding cavity to accommodate the deformation of the product core, so as to facilitate the placement of the product core into the secondary injection molding cavity.

4. The layered injection molding lens mold structure according to claim 3, characterized in that: The reserved gap width is 0.1-2mm.

5. A layered injection molded lens mold structure according to any one of claims 1, 3, and 4, characterized in that: The product core contacts the secondary injection mold through a side edge and the side edge has a certain draft angle.

6. The layered injection molding lens mold structure according to claim 1, characterized in that: The distance between the gate solid and the secondary injection mold is 0.1-2 mm.

7. A layered injection molded lens mold structure according to claim 1 or 6, characterized in that: The cross-sectional shapes of the upper overflow cavity and the lower overflow cavity are rectangular, trapezoidal or arc-shaped.

8. A layered injection molded lens mold structure according to any one of claims 1 to 3, characterized in that: The glue inlet is a rectangular notch arranged in the middle position of one side of the product core, and the glue inlet is communicated with the glue inlet channel.

9. The layered injection molding lens mold structure according to claim 1, characterized in that: The secondary injection molding cavity is provided with at least two secondary injection molding cavities arranged in a mirror image.

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