Novel optical mold compression structure beneficial to rapid injection molding

Abstract

The invention discloses a novel optical mold compression structure beneficial to rapid injection molding. The core of the novel optical mold compression structure is the design of a movable mold core. The movable mold plate is provided with a first through hole, and a guide sliding block and a movable mold insert are fixed in the first through hole. The guide sliding block is provided with a second through hole, the movable mold insert is provided with a third through hole, the guide sliding block is located below the movable mold insert, and the movable mold core penetrates through the through holes of the guide sliding block and the movable mold insert in a sliding mode. The movable mold core comprises a vertical plane guide section and an inclined plane matching section, the vertical plane guide section is matched with the second through hole, and a lower oil groove is formed in the upper-middle part of the vertical plane guide section; the outer side wall of the slope matching section is a first slope, the top inclines towards the center, and an oiling groove is formed in the middle. The inner side wall of the third through hole is arranged to be a second inclined face matched with the first inclined face, and when the movable mold core moves upwards to the highest position, the two inclined faces are attached to each other. A new compression structure is formed by improving the structure between the movable mold core and the movable mold insert, so that the problems of fit clearance and friction burn are solved, and the D1 can be suitable for producing a thin-wall optical mold for rapid injection molding.

Description

Technical Field

[0001] The present invention relates to the field of injection molding technology, and particularly relates to a novel optical mold compression structure that is beneficial to rapid injection molding. Background Art

[0002] Optical thin sheet molds (hereinafter referred to as optical molds) are a type of optical product. The wall thickness design of optical mold injection molded parts is usually less than 1.0 mm, and the injection time is usually less than 0.5 seconds. Therefore, thin-walled optical molds in injection molding require relatively faster speeds and more precise injection mold fit clearances to overcome macroscopic visible warping, bubbles, and other defects that are likely to occur in thin-walled products, while ensuring that optical properties such as optical surface shape and stress are not affected.

[0003] In the prior art, manufacturing optical molds by adopting an injection compression process is a feasible method. For example, "A Novel Injection Compression Mold for HUD Using Belleville Springs" (hereinafter referred to as D1) disclosed in Chinese patent literature, with a publication number of CN212400193U and an authorization announcement date of January 26, 2021. This patent discloses a novel injection compression mold for HUD using Belleville springs, including a fixed mold assembly, a moving mold assembly, and a gating system connecting the cavity of the moving mold assembly. The fixed mold assembly is installed on the moving mold assembly; the moving mold assembly includes a moving mold base plate, on which a thimble bottom plate is provided, a thimble panel is installed on the thimble bottom plate, a backing plate is provided on the thimble panel, a Belleville spring is installed in the backing plate, a moving template is provided on the backing plate, a moving mold insert is provided in the moving template, a moving mold core is fixed on the backing plate, and the moving mold core passes through the moving template and the moving mold insert from bottom to top in sequence; the fixed mold assembly includes a fixed mold base plate, a fixed template is connected to the fixed mold base plate, and a fixed mold insert is installed at the lower part of the fixed template.

[0004] The moving mold core in D1 is of a cuboid structure, and there is a fit clearance between the moving mold core and the moving mold insert to prevent friction and burn. When using D1 to generate an optical mold, the fit clearance is too large. Under the action of the injection compression structure, during rapid molding (less than 0.5 seconds), the plastic liquid will seep out from the fit clearance, and it will be extremely difficult to control the flash problem of the optical mold. If improvement is simply achieved by reducing the fit clearance, it will inevitably cause burns due to friction between the moving mold core and the moving mold insert.

[0005] In view of this, on the basis of D1, by improving the structure between the moving mold core and the moving mold insert to form a new compression structure, the fit clearance problem and the friction burn problem are solved, so that D1 can be applied to the production of thin-walled optical molds for rapid injection molding. Summary of the Invention

[0006] The object of the present invention is to provide a novel optical mold compression structure that is conducive to rapid injection molding to solve the problems described in the background art.

[0007] The technical solution of the present invention is realized as follows:

[0008] A novel optical mold compression structure that is conducive to rapid injection molding, including a moving template. A first through hole that penetrates the moving template up and down is provided in the middle of the moving template. A guide slider and a moving die insert are fixedly arranged in the through hole of the moving template. A second through hole that penetrates the guide slider up and down is provided in the middle of the guide slider. A third through hole that penetrates the moving die insert up and down is provided in the middle of the moving die insert. The guide slider is arranged below the moving die insert. A moving die core is slidably penetrated through the second through hole and the third through hole together. The moving die core includes a vertical surface guiding section with an outer wall of a vertical surface. The vertical surface guiding section protrudes upward to form an inclined surface matching section. The outer wall of the inclined surface matching section is a first inclined surface. The top of the first inclined surface inclines towards the center of the moving die core. A plurality of lower oil grooves are provided on the outer wall of the middle and upper part of the vertical surface guiding section. A plurality of upper oil grooves are provided in the middle of the first inclined surface. The outer wall of the vertical surface guiding section is in sliding fit with the inner wall of the guide slider. The inner wall of the third through hole is set as a second inclined surface that matches the first inclined surface. When the moving die core moves upward to the highest position, the first inclined surface and the second inclined surface are mutually attached. The top of the moving die core is lower than the top of the moving die insert.

[0009] A further technical solution is that the inclination angle of the first inclined surface is 0 - 5°.

[0010] A further technical solution is that the inclination angle of the first inclined surface is 0 - 2°.

[0011] A further technical solution is that the upper oil grooves are cross-shaped oil grooves.

[0012] A further technical solution is that the lower oil grooves are cross-shaped oil grooves.

[0013] A further technical solution is that chamfers are provided at the upper and lower parts of the side edges of the inclined surface matching section, and chamfers are provided at the side edges of the vertical surface guiding section.

[0014] A further technical solution is that the cross-section of the second through hole is rectangular, and the cross-section of the third through hole is rectangular.

[0015] A further technical solution is that it further includes a moving die base plate. A thimble bottom plate is provided on the moving die base plate. A thimble panel is installed on the thimble bottom plate. A backing plate is provided on the thimble panel. A spring is installed in the backing plate. The moving template is slidably installed on the backing plate. The upper end surface of the spring abuts against the lower end surface of the moving template. A compression gap S is left between the bottom of the moving template and the top of the backing plate. The bottom of the moving die core is fixedly arranged on the backing plate.

[0016] A further technical solution is that the range of the compression gap S is 0.5 - 3.0 mm.

[0017] A further technical solution is that the range of the compression gap S is 0.5 - 0.6 mm.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. Good burr prevention effect: The special matching design of the inclined plane matching section and the moving die insert, with reasonable slopes of the first inclined plane and the second inclined plane. When producing an optical thin sheet mold with a thickness less than 0.5 mm, the slope generally does not exceed 5°, and optimally within 2°, which can ensure that the matching gap at the injection cavity before compression is small enough, and the optical mold will not leak from the matching gap during injection compression to generate burrs and flash; the range of the compression gap S is usually 0.5 - 0.6 mm, and it can be close to 0 after injection compression, providing a small enough matching gap. And for optical molds of different thicknesses, the compression gap and slope can be specifically calculated and considered with reference to the flash value of the plastic raw material, with strong adaptability.

[0020] 2. Good lubrication: Multiple cross-shaped lower oil grooves and upper oil grooves are respectively opened on the outer side walls of the vertical plane guiding section and the inclined plane matching section, which can store lubricating oil to form an oil film and reduce sliding friction; chamfers are provided at relevant corners to avoid frictional contact and further reduce the risk of wear and burn.

[0021] 3. High product quality: By improving the matching method of the moving die core, theoretically, a gapless fit can be achieved in the mold closing state. When opening the mold, the first inclined plane of the moving die core is separated from the second inclined plane of the moving die insert, and the gap gradually increases to G, effectively avoiding the burn problem of the compression mold, ensuring that the injection optical mold has no burr problem, and can continuously and stably output optical products with qualified surface type indicators and stress indicators. Description of the Drawings

[0022] Figure 1 It is a schematic diagram of the cooperation between this compression structure and the moving die assembly;

[0023] Figure 2 is Figure 1 a schematic diagram from another perspective;

[0024] Figure 3 is Figure 2 a schematic diagram with the moving die insert hidden;

[0025] Figure 4 It is a cross-sectional view of the cooperation between this compression structure and the moving die assembly;

[0026] Figure 5 is Figure 4 the front view of

[0027] Figure 6Isometric view of this compression structure;

[0028] Figure 7 Is Figure 6 Partial sectional view of;

[0029] Figure 8 Isometric view of the moving mold core;

[0030] Figure 9 Front view of the moving mold core;

[0031] Figure 10 Side view of the moving mold core;

[0032] Figure 11 Moving mold assembly mating diagram before compression of this compression structure;

[0033] Figure 12 Moving mold assembly mating diagram after compression of this compression structure.

[0034] In the figure, 1. Moving mold core, 2. Moving mold insert, 3. Moving mold plate, 4. Backing plate, 5. Guide slider, 6. Vertical surface guiding section, 7. Inclined surface mating section, 8. Upper oil groove, 9. Lower oil groove, 10. Chamfer, 11. Moving mold bottom plate, 12. Ejector pin bottom plate, 13. Ejector pin panel, 14. Spring. Detailed implementation manners

[0035] In order to better understand the technical content of the present invention, specific embodiments are provided below, and the present invention will be further described in conjunction with the accompanying drawings.

[0036] It should be particularly noted that other mating parts of this compression structure are conventional compression mold designs, and the moving mold assembly shown in D1 can be borrowed completely. Except for the moving mold insert 2 and the moving mold core 1, the components and structures of other moving mold assemblies can be borrowed. Naturally, after using the moving mold insert 2 and the moving mold core 1 of this compression structure, corresponding adjustments can be made to some opening parts and hole diameters. These adjustments can be easily achieved by those skilled in the art based on existing design experience and should not pose technical problems.

[0037] The key point of the present invention lies in the slope of the first inclined surface of the inclined surface mating section 7. Taking the mold for producing optical thin sheets with a thickness less than 0.5 mm as an example, the slope of the first inclined surface generally does not exceed 5°, and it is preferably within 2°. The purpose is to ensure a sufficiently small mating gap before compression and prevent flash from occurring during the injection molding process of the product. In principle, when dealing with optical molds of different thicknesses, it is necessary to specifically calculate the compression gap and the slope of the first inclined surface, and consider it with reference to the flash value of the plastic raw material.

[0038] Referring to the structure of the moving die assembly in D1, the moving die assembly includes a moving die base plate. A ejector pin base plate 12 is arranged on the moving die base plate. An ejector pin panel 13 is installed on the ejector pin base plate 12. A backing plate 4 is arranged on the ejector pin panel 13. A spring 14 is installed in the backing plate 4. By squeezing the moving die plate 3 to drive the moving die insert 2, the parting surface is tightened, providing sufficient supporting force to maintain the injection pressure during the injection molding and compression processes. The moving die plate 3 is arranged on the backing plate 4. The upper end surface of the spring 14 abuts against the lower end surface of the moving die plate 3.

[0039] Specifically, a support post is fixed on the right part of the moving die base plate to support the backing plate 4 and prevent the backing plate 4 from deforming due to excessive pressure. The support post sequentially passes through the ejector pin panel 13 and contacts the lower surface of the backing plate 4; a limit block is installed on the ejector pin panel 13 to limit the ejection distance of the ejector pin panel 13, thereby limiting the ejection stroke of the ejector pin; an urethane rubber is installed on the ejector pin base plate 12 to ensure that when the mold is in the closed and uncompressed state, the ejector pin base plate 12 drives the ejector pin to fully return by the elastic force of the urethane rubber; a reset rod is arranged on the urethane rubber. The reset rod sequentially passes through the ejector pin panel 13, the backing plate 4, the moving die plate 3 and contacts the lower surface of the fixed die plate; a rectangular spring is sleeved on the reset rod. The lower surface of the rectangular spring contacts the ejector pin panel 13, and the upper part of the rectangular spring contacts the backing plate 4. After the product is ejected, the ejector pin is driven to automatically return by squeezing the ejector pin panel 13. An ejector pin is fixed on the ejector pin base plate 12 to eject the product and complete the demolding of the product. The ejector pin sequentially passes through the ejector pin panel 13, the backing plate 4, the moving die plate 3 and the moving die insert 2. A thimble hole is formed in the middle of the moving die base plate. The ejector pin and the reset rod are fixed by locking with the ejector pin panel 13, realizing the ejection function and the reset function.

[0040] A moving die insert 2 is arranged in the moving die plate 3. A moving die core 1 is fixed on the backing plate 4. The moving die core 1 sequentially passes through the moving die plate 3 and the moving die insert 2 from bottom to top.

[0041] Contour screws installation holes are formed in the moving die plate 3. The contour screws penetrate into the contour screws installation holes to limit the distance that the moving die plate 3 is expanded by the spring 14, that is, to limit the compression clearance S of the compression space. The lower part of the contour screws is fixedly connected with the backing plate 4; the moving die insert 2 is fixed on the moving die plate 3; the moving die core 1 is locked on the backing plate 4. A guide slider 5 is sleeved on the moving die core 1. The guide slider 5 is installed under the moving die insert 2 on the moving die plate 3 and cooperates with the moving die core 1 to guide and position the moving die core 1, protecting the moving die core 1 from friction and burning with the moving die insert 2 during the compression process.

[0042] A first guiding shaft penetrates through the backing plate 4, upwardly passes through the moving template 3, and penetrates into the fixed template. The first guiding shaft is respectively provided with a first guiding sleeve and a second guiding sleeve from bottom to top. The first guiding sleeve is fixed within the moving template 3, and the second guiding sleeve is fixed within the fixed template, guiding the movement of the moving template 3 and the fixed template; a total of four first guiding shafts are installed on the moving die assembly.

[0043] The moving die base plate is penetrated by a second guiding shaft, and a bushing is sleeved on the second guiding shaft. The bushing is installed within the ejector pin bottom plate 12 and the ejector pin face plate 13. The head of the second guiding shaft penetrates into the backing plate 4, guiding the movement of the ejector pin bottom plate 12 and the ejector pin face plate 13, making the movement more precise. A total of four second guiding shafts 24 are installed on the moving die assembly.

[0044] See Figures 1 to 12 , a novel optical mold compression structure beneficial to rapid injection molding, including the moving template 3 as described in D1. A first through hole penetrating through the moving template 3 vertically is formed in the middle of the moving template 3. A guide slider 5 as described in D1 and a moving die insert 2 with a special design are fixedly arranged in the through hole of the moving template 3. A second through hole penetrating through the guide slider 5 vertically is formed in the middle of the guide slider 5. A third through hole penetrating through the moving die insert 2 vertically is formed in the middle of the moving die insert 2. The guide slider 5 is arranged below the moving die insert 2 as shown in D1. A moving die core 1 is slidably penetrated through the second through hole and the third through hole together. The moving die core 1 includes a vertical surface guiding section 6 with a vertical surface outer wall. The vertical surface guiding section 6 protrudes upward to form an inclined surface matching section 7. The outer wall of the inclined surface matching section 7 is a first inclined surface. The top of the first inclined surface inclines towards the center of the moving die core 1. A plurality of lower oil grooves 9 are formed in the outer wall of the middle and upper part of the vertical surface guiding section 6. A plurality of upper oil grooves 8 are formed in the middle of the first inclined surface. The outer wall of the vertical surface guiding section 6 is in sliding fit with the inner wall of the guide slider 5. The inner wall of the third through hole is set as a second inclined surface matching the first inclined surface. When the moving die core 1 moves upward to the highest position, the first inclined surface and the second inclined surface are mutually attached. The top of the moving die core 1 is lower than the top of the moving die insert 2.

[0045] It should be specifically noted that the sliding fit between the outer wall of the vertical guiding section and the inner wall of the guide slider 5 mentioned above means that there is an extremely thin oil film between them to provide lubrication for the contact surface between the two. The mutual attachment between the first inclined surface and the second inclined surface mentioned above means that there is an extremely thin oil film between them to provide buffering and lubrication when they are in contact.

[0046] Specifically, the cross-section of the second through hole is rectangular, and the cross-section of the third through hole is rectangular, that is, the cross-section of the vertical surface guiding section 6 cooperating with the second through hole has a rectangular basic contour, and the cross-section of the inclined surface matching section 7 cooperating with the third through hole has a rectangular basic contour.

[0047] Specifically, the inclination angle of the first inclined surface is 0 to 5°.

[0048] Preferably, the inclination angle of the first inclined surface is 0 to 2°.

[0049] Specifically, the oil groove 8 is a cross-shaped oil groove.

[0050] When using the above solution, the lubricating oil stored in the oil groove 8 can provide lubricating oil during sliding friction to form an oil film.

[0051] Specifically, the lower oil groove 9 is a cross-shaped oil groove.

[0052] When using the above solution, the lubricating oil stored in the lower oil groove 9 can provide lubricating oil during sliding friction to form an oil film.

[0053] Specifically, chamfers 10 are provided at the upper, middle and lower parts of the side edges of the inclined surface mating section 7, and chamfers 10 are provided at the side edges of the vertical surface guiding section 6.

[0054] When using the above solution, the chamfers 10 can avoid frictional contact between the corners of the vertical surface guiding section 6 and the inclined surface mating section 7 and the corners of the second through hole and the third through hole, and the upper part of the side edge of the inclined surface mating section 7 is reserved to provide the necessary mating clearance.

[0055] Preferably, the range of the compression clearance S is 0.5 - 0.6 mm. As Figure 11 shown, the compression clearance S and the mating clearance G are very small. The compression spacing S is usually between 0.5 - 0.6 mm according to the debugging requirements of the injection molding process, and the compression clearance S will be close to 0 during mold matching.

[0056] The working principle of the present invention:

[0057] When this compression structure is used, the top of the moving mold core 1 is the optical product surface. Before mold opening, under the action of the spring 14, the backing plate 4 moves upward, the backing plate 4 drives the moving mold insert 2 to move upward, and the moving mold insert 2 and the moving mold core 1 are separated and do not contact along the first inclined surface and the second inclined surface. Because the first inclined surface and the second inclined surface do not contact during separation and there is enough clearance, there will be no friction during the separation process, avoiding burns during the separation process.

[0058] The drop space between the top of the moving mold core 1 and the top of the moving mold insert 2 forms the injection cavity of the optical mold. Due to the cooperative design of the first inclined surface and the second inclined surface, the fitting clearance formed between the top edge of the moving mold core 1 at the injection cavity and the third through hole can be small enough so that the optical mold will not leak from the fitting clearance during injection compression to generate flash and burrs. After injection molding is completed, the moving template 3 moves towards the direction of the moving mold bottom plate 11 under the extrusion action, and the moving template 3 drives the moving mold insert 2 to move. Since the first inclined surface at the upper end of the moving mold core 1 and the second inclined surface of the moving mold insert 2 are in inclined surface cooperation, the first inclined surface and the second inclined surface are only in contact and cooperation at the moment when the compression action is completed. No friction and wear will occur during this process, reducing the risk of burning while providing a small enough fitting clearance.

[0059] Among them, by setting the guide slider 5 to limit the vertical surface guiding section 6, the movement accuracy during compression can be further ensured.

[0060] In the present disclosure, the original vertical surface fitting method (completely relying on the fitting clearance to control flash) of the moving mold core 1 in D1 is improved to inclined surface fitting, so that in theory, a gapless fit can be achieved in the closed mold state.

[0061] At the same time, the present disclosure provides actual cases to show the inclined angle of the inclined surface and solve the problem of inclined surface lubrication, providing a reliable technical solution for the actual production of optical thin sheet molds, which can effectively avoid the burning problem of compression molds, and ensure that the injection-molded optical molds have no flash problem, and can continuously and stably output optical products with qualified surface type indicators and stress indicators.

[0062] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A novel optical mold compression structure that is conducive to rapid injection molding, comprising a movable mold plate, a first through hole is provided in the middle of the movable mold plate and penetrates the movable mold plate vertically, a guide slider and a movable mold insert are fixedly arranged in the through hole of the movable mold plate, a second through hole is provided in the middle of the guide slider and penetrates the guide slider vertically, a third through hole is provided in the middle of the movable mold insert and penetrates the movable mold insert vertically, the guide slider is arranged below the movable mold insert, and a movable mold core is slidably penetrated in the second through hole and the third through hole, characterized in that: The dynamic model core includes a vertical surface guide section with an outer wall of a vertical surface, the vertical surface guide section protrudes upward to form a sloped surface matching section, the outer wall of the sloped surface matching section is a first slope, the top of the first slope is inclined toward the center of the dynamic model core, a plurality of lower oil grooves are provided on the outer wall of the upper and middle parts of the vertical surface guide section, a plurality of upper oil grooves are provided in the middle part of the first slope, the outer wall of the vertical surface guide section is slidably connected with the inner wall of the guide sliding block, the inner wall of the third through hole is set to be a second slope matched with the first slope, when the dynamic model core moves upward to the highest point, the first slope and the second slope are fitted with each other, and the top of the dynamic model core is lower than the top of the dynamic mold insert.

2. According to claim 1, a novel optical mold compression structure that is conducive to rapid injection molding is characterized in that: The inclination angle of the first inclined surface is 0-5°.

3. According to claim 2, a novel optical mold compression structure that is conducive to rapid injection molding is characterized in that: The inclination angle of the first inclined surface is 0-2°.

4. According to claim 1, a novel optical mold compression structure that is conducive to rapid injection molding is characterized in that: The upper oil groove is a cross-shaped oil groove.

5. According to claim 1, a novel optical mold compression structure that is conducive to rapid injection molding is characterized in that: The lower oil groove is a cross-shaped oil groove.

6. According to claim 1, a novel optical mold compression structure that is conducive to rapid injection molding is characterized in that: The middle and upper parts of the side edges of the inclined surface matching section are provided with chamfers, and the side edges of the vertical surface guiding section are provided with chamfers.

7. According to claim 3, a novel optical mold compression structure that is conducive to rapid injection molding is characterized in that: The cross section of the second through hole is rectangular, and the cross section of the third through hole is rectangular.

8. A novel optical mold compression structure that is advantageous for rapid injection molding according to any one of claims 1 to 7, characterized in that: It also includes a movable mold base plate, which is provided with an ejector base plate, an ejector panel is installed on the ejector base plate, a pad is provided on the ejector panel, a spring is installed in the pad, the movable mold plate is slidably installed on the pad, a spring hole is opened in the pad, the lower end surface of the spring is located in the spring hole, the upper end surface of the spring is against the lower end surface of the movable mold, a compression gap S is left between the bottom of the movable mold and the top of the pad, and the bottom of the movable mold core is fixed on the pad.

9. The novel optical mold compression structure that is advantageous for rapid injection molding according to claim 8 is characterized in that: The range of the compression gap S is 0.5-3.0 mm.

10. The novel optical mold compression structure that is advantageous for rapid injection molding according to claim 9 is characterized in that: The range of the compression gap S is 0.5-0.6 mm.

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