Injection molding equipment for low-stress aspheric optical lens

Abstract

The invention provides injection molding equipment for a low-stress aspheric optical lens, and relates to the field of injection molding machines, the injection molding equipment comprises an injection barrel, a heating seat is fixedly arranged on the outer side of the injection barrel, a plurality of groups of heating pieces are fixedly arranged in the heating seat, and a screw rod is movably inserted into the injection barrel in a penetrating manner; a feeding section, a compression section and a metering section are respectively arranged on the screw rod, a low-stress mechanism is mounted on the outer side of the feeding section, a barrier glue melting mechanism is mounted on the outer side of the compression section, mixing stirring blades are arranged on the outer side of the metering section, and a feeding hole is formed in the end part of the injection barrel. According to the injection molding equipment for the low-stress aspheric optical lens, air in the material injection barrel can enter the negative pressure channel from the one-way hole and the air inlet channel and is discharged from the vacuumizing pipe, so that the interior of the material injection barrel is vacuumized, moisture, air and gas volatile matters in materials can be discharged, and crazing or bubbles of the lens are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of optical lens manufacturing, and specifically to an injection molding device for low-stress aspherical optical lenses. Background Art

[0002] A lens, also known as an optical lens, refers to a transparent material made of optical materials such as glass or resin and having one or more curved surfaces, which can be used in structures such as lighting fixtures and display modules; optical lenses are generally processed by turning, but for some special devices, aspherical lenses need to be used, and the processing of aspherical lenses generally adopts an injection molding method; that is, molten glass or plastic is injected into a mold for cooling and forming; specifically, the heated and melted glass or plastic is injected into the mold cavity by a high-pressure injection molding machine, and after cooling and solidifying, a formed part is obtained; the processing steps of an injection mold are: first, the mold is closed to obtain an injection cavity, then molten plastic or glass is injected into the injection cavity by an injection molding machine, and after cooling and forming, the optical lens is ejected by a thimble; in this way, the lens surface is easily damaged during the process of ejecting the lens, reducing the quality of the lens.

[0003] To solve the above problems, in the prior art, such as a Chinese patent with the publication number CN217573872U, a rapid prototyping device for aspherical optical lenses is disclosed. The device includes a mounting plate for mounting on equipment, and further includes: a base, which is fixedly arranged on the mounting plate and forms an integral structure with the mounting plate; a lower mold, which is fixedly arranged on the base; Although the above device can avoid damaging the lens surface and effectively improve the quality of the lens, and only the edge of the lens needs to be ground later. However, when the optical lens mold is injecting material during actual use, an injection molding device needs to be used. The screw inside the injection molding rotates, so that the discharge port at the end of the barrel on the injection molding device is inserted into the feed port of the mold to complete the injection work. When the screw inside the barrel rotates for injection, the injection efficiency is low, and the plasticizing ability of the injection screw is insufficient. When producing polycarbonate (PC) lenses, insufficient plasticization will cause turbidity spots on the lens surface, affecting the optical performance.

[0004] Therefore, it is necessary to improve the existing equipment for the current technical problems. Summary of the Invention

[0005] The purpose of the present invention is to provide an injection molding device for low-stress aspherical optical lenses to solve the defects mentioned in the above background art.

[0006] [[ID=2,4]]To achieve the above purpose, the following specific technical solutions are adopted: An injection molding device for a low-stress aspherical optical lens, comprising a feeding barrel, a heating base is fixedly arranged on the outer side of the feeding barrel, a plurality of heating sheets are fixedly arranged inside the heating base, a screw rod is movably inserted inside the feeding barrel, a feeding section, a compression section and a metering section are respectively arranged on the screw rod, a low-stress mechanism is installed on the outer side of the feeding section, a barrier melting mechanism is installed on the outer side of the compression section, a mixing stirring blade is arranged on the outer side of the metering section, and a feeding port is opened at the end of the feeding barrel.

[0007] Further, the feeding barrel comprises a barrier melting mechanism, a deep plasticizing tank, a mixing stirring blade, a low-stress mechanism and a lining barrel, the lining barrel is fixedly arranged on the circumferential inner wall of the feeding barrel, and both ends of the lining barrel are tapered.

[0008] Further, a deep plasticizing tank is opened in the middle of the lining barrel, the deep plasticizing tank is spiral-shaped, the deep plasticizing tank is arranged between the compression section and the metering section, and the pitch of the spiral-shaped deep plasticizing tank is the same as that of the spiral blades on the compression section and the metering section.

[0009] Further, a plurality of mixing stirring blades are uniformly arranged on the metering section, the plurality of mixing stirring blades are uniformly distributed along the circumferential outer wall of the metering section, and the mixing stirring blades are diamond-shaped.

[0010] Further, the barrier melting mechanism comprises a blade and a frame, the frame is annular, the frame is fixedly arranged on the circumferential inner wall of the lining barrel, and a plurality of blades are uniformly and fixedly arranged on the circumferential inner wall of the frame.

[0011] Further, a barrier melting channel is formed between two adjacent blades, and a cutting edge is fixedly arranged at the end of the blade.

[0012] Further, the low-stress mechanism comprises an exhaust cylinder, a one-way hole, a negative pressure channel, an air inlet channel, a communication hole and a vacuum extraction tube, the exhaust cylinder is fixedly connected to the circumferential inner wall of the feeding barrel, a plurality of one-way holes are uniformly opened on the circumferential inner wall of the exhaust cylinder, and the diameter of the one-way hole is 90 microns.

[0013] Further, a negative pressure channel and an air inlet channel are opened on the inner wall of the feeding barrel, both the negative pressure channel and the air inlet channel are spiral-shaped, a communication hole is arranged at the right end of the negative pressure channel, a vacuum extraction tube is inserted and fixed inside the communication hole, and the vacuum extraction tube is "L"-shaped.

[0014] Further, the axial sections of the feeding barrel and the exhaust cylinder are concentric circle structures, an inlet section is arranged inside the exhaust cylinder, and the axial sections of the exhaust cylinder and the inlet section are concentric circle structures.

[0015] Compared with the prior art, the beneficial effects of the present invention are: When the material flows inside the injection barrel in the present invention, under the action of an external negative pressure device, a negative pressure is formed inside the negative pressure channel. The air inside the injection barrel can enter the inside of the negative pressure channel from the one-way holes and the air intake channel, and is discharged from the vacuum extraction tube, completing the vacuum pumping work inside the injection barrel. Moisture, air, and gas volatiles in the material can be discharged, avoiding silver streaks or bubbles in the lens. After the gas in the melt is discharged, its viscosity will be significantly reduced. After its fluidity is improved, the melt is more likely to be evenly distributed during the screw conveying and mold filling processes, reducing the shear stress caused by uneven flow velocity, achieving the purpose of low-stress injection molding of optical lenses, avoiding the oxidation that is likely to occur when the melt contacts air during injection molding, which may lead to the breakage or cross-linking of molecular chains, and improving the injection molding quality of the product; In the present invention, a blocking melt channel is formed between two adjacent groups of blades, and a cutting edge is fixedly arranged at the end of the blade. The molten melt and small particles can pass through the melt channel, and the unmolten large particles are blocked outside the melt channel and continue to be subjected to shear and heat conduction until they are melted and reduce in volume, and then can enter the compression section through the melt channel for treatment. The unmolten large-particle materials are blocked outside the blocking melt channel and are gradually melted through continuous shear force and heat conduction, avoiding the direct entry of unmolten particles into the compression section, ensuring that the temperature and viscosity of the melt entering the subsequent link are more uniform, reducing defects such as bubbles, weld lines, and insufficient strength in the product caused by poor plasticization of the material, improving the plasticization ability of the equipment, and having a high plasticization efficiency; In the present invention, the deep plasticization tank is arranged between the compression section and the metering section. When the molten material transitions from the compression section to the metering section, the spiral trajectory of the deep plasticization tank can guide the material to generate continuous radial disturbance and shunt mixing effects during the axial advancement process, similar to the effect of dynamic stirring. After the material enters the deep plasticization tank, due to the guiding action of the spiral structure, it will experience repeated compression, extension, and shear deformation, promoting full contact between the interface of plastic particles and the melt, accelerating the melting and fragmentation of solid particles. The spiral path extends the movement trajectory of the material in the tank, making the melt viscosity distribution more uniform and the molecular chain orientation more consistent, and can effectively discharge gas and eliminate micro-defects. Finally, the internal structure of the thick product is denser and more transparent after curing, and the processed lens will not have cloudy spots, ensuring its optical performance and naturally improving the light transmittance; After the molten material of the present invention is processed through the compression section, it enters the metering section. A plurality of mixing and stirring blades are arranged on the metering section, and the mixing and stirring blades are arranged in a diamond shape. When the compression section rotates, it can drive a large number of mixing and stirring blades thereon to rotate, completing the stirring work of the material. When the material flows through the metering section, the plurality of mixing and stirring blades divide the material flow, changing the flow direction of the material and rearranging the flow bundles; at the same time, the plurality of mixing and stirring blades will also cause agitation of the material flow, generating local high shear, which helps the melting of solid particles, promotes uniform mixing of the material, and enhances the stirring effect; non-pelletizing additives can effectively achieve uniform stirring and color mixing, thereby meeting the requirements of various grades of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a front view schematic diagram of the structure of the present invention.

[0017] Figure 2 It is a schematic diagram of the barrier melting mechanism of the structure of the present invention.

[0018] Figure 3 It is a cross-sectional view of the barrier melting mechanism of the structure of the present invention.

[0019] Figure 4 It is a schematic diagram of the barrier melting mechanism and the mixing and stirring blade structure in the structure of the present invention.

[0020] Figure 5 It is a schematic diagram of the surface structure of the metering section of the structure of the present invention.

[0021] Figure 6 It is the structure of the present invention Figure 5 bottom view.

[0022] Figure 7 It is a schematic diagram of the low-stress mechanism of the structure of the present invention.

[0023] Figure 8 It is the structure of the present invention Figure 7 explosion diagram.

[0024] In the figure: 1 injection barrel, 11 barrier melting mechanism, 111 blade, 112 frame, 1111 cutting edge, 1112 blocking melting channel, 12 deep plasticizing tank, 13 mixing and stirring blade, 14 low-stress mechanism, 141 exhaust barrel, 142 one-way hole, 143 negative pressure channel, 144 intake channel, 145 communication hole, 146 extraction vacuum tube, 15 inner lining barrel, 2 heating seat, 3 heating sheet, 4 screw, 41 feeding section, 42 compression section, 43 metering section, 44 feeding port. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] In order to further illustrate the technical solution of the present invention, the following specific embodiments are adopted.

[0026] Example: An injection molding device for a low-stress aspherical optical lens developed by our company is as follows Figures 1 - 8 shown

[0027] Specifically, the device includes a feed cylinder 1. A heating base 2 is fixedly arranged on the outer side of the feed cylinder 1. A plurality of heating sheets 3 are fixedly arranged inside the heating base 2. A screw 4 is movably inserted inside the feed cylinder 1. An inlet section 41, a compression section 42 and a metering section 43 are respectively arranged on the screw 4. A low-stress mechanism 14 is installed on the outer side of the inlet section 41. A barrier melting mechanism 11 is installed on the outer side of the compression section 42. A mixing stirring blade 13 is arranged on the outer side of the metering section 43. A feed inlet 44 is opened at the end of the feed cylinder 1

[0028] Based on the above technical solution, the specific details are as follows The feed cylinder 1 includes a barrier melting mechanism 11, a deep plasticizing groove 12, a mixing stirring blade 13, a low-stress mechanism 14 and a lining cylinder 15. The lining cylinder 15 is fixedly arranged on the circumferential inner wall of the feed cylinder 1. Both ends of the lining cylinder 15 are tapered. A deep plasticizing groove 12 is opened in the middle of the lining cylinder 15. The deep plasticizing groove 12 is arranged in a spiral shape. The deep plasticizing groove 12 arranged in a spiral shape is between the compression section 42 and the metering section 43. The pitch of the spiral deep plasticizing groove 12 is the same as that of the spiral blades on the compression section 42 and the metering section 43. This embodiment is a further limitation of the third specific embodiment. A plurality of mixing stirring blades 13 are evenly arranged on the metering section 43. The plurality of mixing stirring blades 13 are evenly distributed along the circumferential outer wall of the metering section 43. The mixing stirring blade 13 is arranged in a diamond shape

[0029] The barrier melting mechanism 11 includes a blade 111 and a frame 112. The frame 112 is arranged in a ring shape. The frame 112 is fixedly arranged on the circumferential inner wall of the lining cylinder 15. A plurality of blades 111 are evenly and fixedly arranged on the circumferential inner wall of the frame 112. A barrier melting channel 1112 is formed between two adjacent blades 111. A cutting edge 1111 is fixedly arranged at the end of the blade 111

[0030] The low-stress mechanism 14 includes an exhaust cylinder 141, a one-way hole 142, a negative pressure channel 143, an air inlet channel 144, a communication hole 145 and a vacuum extraction pipe 146. The exhaust cylinder 141 is fixedly connected to the circumferential inner wall of the feed cylinder 1. A plurality of one-way holes 142 are evenly opened on the circumferential inner wall of the exhaust cylinder 141. The diameter of the one-way hole 142 is 90 microns

[0031] On the inner wall of the injection barrel 1, a negative pressure channel 143 and an air inlet channel 144 are provided. Both the negative pressure channel 143 and the air inlet channel 144 are arranged in a spiral shape. A communication hole 145 is provided at the right end of the negative pressure channel 143. A vacuum extraction tube 146 is fixedly inserted inside the communication hole 145. The vacuum extraction tube 146 is arranged in an "L" shape. The axial cross-sections of the injection barrel 1 and the exhaust barrel 141 are concentric circle structures. An inlet section 41 is provided inside the exhaust barrel 141. The axial cross-sections of the exhaust barrel 141 and the inlet section 41 are concentric circle structures.

[0032] During actual use, a hopper can be installed at the material inlet 44. The molten material for making lenses can enter the inside of the injection barrel 1 from the material inlet 44. At this time, the screw 4 rotates to convey the material inside the injection barrel 1 and enter the inside of the mold core from the gate of the mold, completing the molding work of the lens. When the material flows inside the injection barrel 1, under the action of an external negative pressure device, a negative pressure is formed inside the negative pressure channel 143. The air inside the injection barrel 1 can enter the inside of the negative pressure channel 143 from the one-way hole 142 and the air inlet channel 144, and is discharged from the vacuum extraction tube 146, completing the vacuum pumping work inside the injection barrel 1. The moisture, air, and gas volatiles in the material can be discharged, avoiding silver streaks or bubbles in the lens. High-transparency materials have extremely high requirements for the integrity of the molecular structure. In traditional injection molding, the melt in contact with air is prone to oxidation, resulting in the breakage or cross-linking of molecular chains and the formation of chemical stress. The vacuum environment can significantly reduce the contact between the melt and oxygen, reduce the probability of oxidation reaction, and at the same time inhibit the generation of low-molecular-weight volatiles, avoiding internal stress caused by uneven composition. In a vacuum environment, the gas in the melt is discharged, and its viscosity will be significantly reduced. After its fluidity is improved, the melt is more likely to be evenly distributed during the screw conveying and mold filling processes, reducing the shear stress caused by uneven flow velocity. In addition, the vacuum helps the melt to form a more stable laminar flow inside the barrel, avoiding inconsistent molecular orientation caused by turbulence in traditional injection molding, thereby reducing the internal stress difference of the finished product; achieving the purpose of low-stress injection molding of optical lenses; the aperture of the one-way hole 142 is 90 microns, which can play a certain blocking role for the material and at the same time may allow gas to pass through; however, in actual applications, it is necessary to adjust and test according to specific material characteristics and injection molding requirements to determine the appropriate aperture of the one-way hole 142.

[0033] When the molten material flows inside the injection barrel 1, the material impacts on the barrier melting mechanism 11 at this time. The barrier melting mechanism 11 is provided with an annular frame 112. On its circumferential inner wall, multiple groups of blades 111 are evenly and fixedly arranged. Between two adjacent groups of blades 111, a barrier melting channel 1112 is formed. At the end of the blade 111, a cutting edge 1111 is fixedly arranged. The molten melt and small particles can pass through the barrier melting channel 1112, while the unmolten large particles are blocked outside the barrier melting channel 1112 and continue to be subjected to shearing and heat conduction until they are melted and their volume is reduced, and then they can enter the compression section 42 through the barrier melting channel 1112 for processing. The unmolten large particle materials are blocked outside the barrier melting channel 1112 and are gradually melted through the continuous shearing force and heat conduction, avoiding the direct entry of unmolten particles into the compression section 42, ensuring that the temperature and viscosity of the melt entering the subsequent process are more uniform, and reducing defects such as bubbles, weld lines, and insufficient strength caused by poor plasticization of the material; The barrier melting mechanism 11 is linearly arranged in two groups, which can perform secondary treatment on the molten material to ensure that there are no large particle materials in the molten material, improving the plasticization ability and injection molding efficiency; The material entering the inside of the compression section 42 can enter the inside of the deep plasticization tank 12. The deep plasticization tank 12 is arranged between the compression section 42 and the metering section 43. When the molten material transitions from the compression section 42 to the metering section 43, the spiral trajectory of the deep plasticization tank 12 can guide the material to generate a continuous radial disturbance and shunt mixing effect during the axial advancement process, similar to the effect of dynamic stirring. After the material enters the deep plasticization tank 12, due to the guiding action of the spiral structure, it will experience repeated compression, extension, and shear deformation, promoting the full contact between the interface of the plastic particles and the melt, accelerating the melting and fragmentation of the solid particles, and at the same time dispersing components such as additives and pigments more evenly into the melt, fundamentally reducing plasticization blind spots, such as problems of unmolten particles and uneven local temperature, so as to achieve the improvement of plasticization integrity; When the material is not sufficiently plasticized, unmolten particles, bubbles or phase separation regions are easily left inside. These defects will become light scattering centers, resulting in a decrease in light transmittance; The spiral deep plasticization tank 12 enhances the shearing and mixing of the material and the residence time. The spiral path prolongs the movement trajectory of the material in the tank, making the melt viscosity distribution more uniform and the molecular chain orientation more consistent, and can effectively discharge gases and eliminate microscopic defects. Finally, the internal structure of the thick product after curing is denser and more transparent, and the light transmittance is naturally improved.

[0034] After the molten material is processed through the compression section 42, it enters the metering section 43. Multiple groups of mixing stirring blades 13 are arranged on the metering section 43. The mixing stirring blades 13 are arranged in a diamond shape. When the compression section 42 rotates, it can drive a large number of the mixing stirring blades 13 thereon to rotate, completing the stirring work of the material. When the material flows through the metering section 43, the multiple groups of mixing stirring blades 13 divide the material flow, changing the flow direction of the material and rearranging the flow bundles. At the same time, the multiple groups of mixing stirring blades 13 will also cause agitation of the material flow, generating local high shear, which helps to melt solid particles, promotes uniform mixing of the material, and enhances the stirring effect. The unmelted material is melted more fully, and the melted material can also be further mixed, thus achieving better stirring and homogenization effects in the metering section. This enables non-pelletized additives to be effectively and evenly stirred and color-mixed, thereby meeting the various grade requirements of the product.

[0035] It is obvious to those skilled in the art that based on the above teaching content, certain modifications, combinations, and variations can also be made.

Claims

1. An injection molding device for a low-stress aspherical optical lens, comprising a charging barrel (1), characterized in that: A heating base (2) is fixedly arranged on the outer side of the charging cylinder (1). A plurality of heating sheets (3) are fixedly arranged inside the heating base (2). A screw rod (4) is movably inserted into the charging cylinder (1). An inlet section (41), a compression section (42) and a metering section (43) are respectively arranged on the screw rod (4). A low-stress mechanism (14) is installed on the outer side of the inlet section (41). A barrier melting mechanism (11) is installed on the outer side of the compression section (42). A mixing and stirring blade (13) is arranged on the outer side of the metering section (43). A material inlet (44) is opened at the end of the charging cylinder (1).

2. The injection molding equipment for a low-stress aspherical optical lens according to claim 1, characterized in that: The charging cylinder (1) includes a barrier melting mechanism (11), a deep plasticizing groove (12), a mixing and stirring blade (13), a low-stress mechanism (14) and a lining cylinder (15). The lining cylinder (15) is fixedly arranged on the circumferential inner wall of the charging cylinder (1). Both ends of the lining cylinder (15) are tapered.

3. The injection molding device for a low-stress aspherical optical lens according to claim 2, wherein: A deep plasticizing groove (12) is opened in the middle of the lining cylinder (15). The deep plasticizing groove (12) is spiral-shaped. The deep plasticizing groove (12) is arranged between the compression section (42) and the metering section (43). The pitch of the spiral-shaped deep plasticizing groove (12) is the same as that of the spiral blades on the compression section (42) and the metering section (43).

4. The injection molding device for a low-stress aspherical optical lens according to claim 3, characterized in that: A plurality of mixing and stirring blades (13) are evenly arranged on the metering section (43). The plurality of mixing and stirring blades (13) are evenly distributed along the circumferential outer wall of the metering section (43). The mixing and stirring blade (13) is diamond-shaped.

5. The injection molding equipment for a low-stress aspherical optical lens according to claim 2, characterized in that: The barrier melting mechanism (11) includes blades (111) and a frame (112). The frame (112) is annular. The frame (112) is fixedly arranged on the circumferential inner wall of the lining cylinder (15). A plurality of blades (111) are evenly and fixedly arranged on the circumferential inner wall of the frame (112).

6. The injection molding equipment for a low-stress aspherical optical lens according to claim 5, characterized in that: A blocking melting channel (1112) is formed between two adjacent blades (111). A cutting edge (1111) is fixedly arranged at the end of the blade (111).

7. The injection molding equipment for a low-stress aspherical optical lens according to claim 1, characterized in that: The low-stress mechanism (14) includes an exhaust cylinder (141), one-way holes (142), a negative pressure channel (143), an air inlet channel (144), a communication hole (145) and a vacuum extraction pipe (146). The exhaust cylinder (141) is fixedly connected to the circumferential inner wall of the charging cylinder (1). A plurality of one-way holes (142) are evenly opened on the circumferential inner wall of the exhaust cylinder (141). The diameter of the one-way hole (142) is 90 microns.

8. An injection molding device for a low-stress aspherical optical lens according to claim 7, characterized in that: A negative pressure channel (143) and an air inlet channel (144) are opened on the inner wall of the charging cylinder (1). Both the negative pressure channel (143) and the air inlet channel (144) are spiral-shaped. A communication hole (145) is arranged at the right end of the negative pressure channel (143). A vacuum extraction pipe (146) is inserted and fixed inside the communication hole (145). The vacuum extraction pipe (146) is in an "L" shape.

9. The injection molding equipment for a low-stress aspherical optical lens according to claim 7, characterized in that: The axial cross-sections of the charging cylinder (1) and the exhaust cylinder (141) are concentric structures. The inlet section (41) is arranged inside the exhaust cylinder (141). The axial cross-sections of the exhaust cylinder (141) and the inlet section (41) are concentric structures.

Images