Efficient injection molding process for automotive lamp lens based on multi-cavity mold

Abstract

The invention discloses an efficient injection molding process for a vehicle lamp lens based on a multi-cavity mold. The efficient injection molding process comprises the following steps: S1, mold design; an injection mold with a plurality of cavities is designed, and molten plastic can be independently injected into each cavity; s2, designing a cooling system; in the mold design, a multi-point cooling water channel is arranged; S3, materials are selected and matched; the preparation method comprises the following steps: selecting a plastic base material with optical transparency and impact resistance, adding 97-99 parts by mass of the plastic base material, 1-3 parts by mass of a UV stabilizer and 0.1-0.3 part by mass of an antioxidant in proportion, and fully mixing; s4, optimization of injection molding parameters including injection pressure, injection speed, cooling time and dwell time; s5, quality monitoring; optical performance detection: monitoring the light transmittance and chromatic aberration of the lens by adopting optical detection equipment, and ensuring that the light transmittance of the lens is greater than or equal to 90% and the chromatic aberration is delta Elt; 1; and physical property detection: according to the ASTM D256 standard and the ASTM D1525 standard, regularly sampling and detecting the physical properties of the lens, including the impact strength and the vicat softening point, so as to ensure that the finished product meets the industrial standard.

Description

Technical Field

[0001] The invention relates to a high-efficiency injection molding process for a vehicle lamp lens based on a multi-cavity mold. Background Art

[0002] In the automotive lighting system, the quality of the headlight lens directly affects the lighting effect and driving safety. With the rapid development of the automotive industry, the production efficiency and quality requirements for headlight lenses are constantly increasing. The traditional single-cavity mold injection molding process has the following shortcomings:

[0003] Low production efficiency: A single-cavity mold can only produce one lens at a time, resulting in a long production cycle.

[0004] Large material waste: Due to uneven filling during the injection molding process, material waste is caused.

[0005] Poor product consistency: There are differences in the optical performance and physical properties of different batches of products.

[0006] Therefore, it is particularly important to develop an efficient injection molding process based on multi-cavity molds. Summary of the invention

[0007] The purpose of the present invention is to solve the above deficiencies in the prior art and provide an efficient injection molding process for a headlight lens based on a multi-cavity mold.

[0008] The efficient injection molding process of the headlight lens based on a multi-cavity mold includes the following steps:

[0009] S1: mold design;

[0010] Design an injection mold with multiple cavities, each of which can be independently injected with molten plastic, with 4-12 cavities;

[0011] S2: Cooling system design;

[0012] Multi-point cooling design: In the mold design, multiple cooling water channels are set up, and 2-4 cooling water channels are arranged around each cavity to ensure uniform cooling effect. The cooling water temperature is controlled between 10-15℃ to shorten the cooling cycle;

[0013] Temperature monitoring system: Introduce temperature sensors to monitor mold temperature in real time, and set the temperature range to 60-80°C to ensure stability during the injection molding process;

[0014] S3: Material selection and proportion;

[0015] Select a plastic substrate with optical transparency and impact resistance, add 97-99 parts by mass of the plastic substrate, 1-3 parts by mass of a UV stabilizer and 0.1-0.3 parts by mass of an antioxidant in proportion, and mix thoroughly;

[0016] S4: Injection molding parameters optimization;

[0017] Injection pressure: Set the injection pressure in the range of 800-1200 bar to ensure that the molten plastic can fully fill the mold;

[0018] Injection speed: Using variable speed injection technology, the initial injection speed is set at 50cm / s, and then gradually accelerated to reduce the shear stress of the melt and ensure uniform filling;

[0019] Cooling time: The cooling time of the mold is optimized according to the thickness and size of the lens and is set to 40-60 seconds to ensure that the lens can cool quickly and maintain its shape after molding;

[0020] Holding time: Set the holding time to 8-12 seconds to ensure that the product does not shrink or warp during the cooling process;

[0021] S5: Quality monitoring;

[0022] Optical performance testing: During the production process, optical testing equipment is used to monitor the transmittance and color difference of the lens to ensure that the lens transmittance is ≥90% and the color difference ΔE<1;

[0023] Physical property testing: Regular sampling and testing of the physical properties of lenses, including impact strength and Vicat softening point, is performed according to ASTM D256 and ASTM D1525 standards to ensure that finished products meet industry standards.

[0024] As a further improvement, the mold material described in S1 is selected from alloy steel H13 or P20 to ensure the durability and long-term stability of the mold.

[0025] As a further improvement, the inner surface of the mold described in S1 is mirror polished, and the Ra value is controlled within 0.2 μm to improve the optical performance and reduce the demoulding resistance.

[0026] As a further improvement, the temperature sensor described in S2 is a thermocouple.

[0027] As a further improvement, the plastic substrate described in S3 is polycarbonate or polymethyl methacrylate.

[0028] As a further improvement, the UV stabilizer described in S3 is UV-328, and the antioxidant is BHT.

[0029] Beneficial effects:

[0030] 1. Improve production efficiency

[0031] Multi-cavity mold design: By producing multiple lenses at one time, the production time of each lens is significantly reduced, and the overall output is increased.

[0032] Fast cycle time: Optimized cooling and holding time enable the mold to complete an injection cycle in a shorter time, speeding up the production process.

[0033] 2. Reduce production costs

[0034] High material utilization: Multi-cavity molds can make full use of raw materials and reduce waste, thereby reducing the production cost of each lens.

[0035] Reduce labor and equipment costs: Improved production efficiency means that more products can be produced in the same amount of time, reducing the frequency of use of manpower and equipment.

[0036] 3. Improve product quality

[0037] Consistency and stability: The design of multi-cavity molds ensures that the molding conditions of each lens are the same, reducing quality fluctuations between batches and improving product consistency.

[0038] Excellent optical performance: By selecting high-quality raw materials and optimizing the injection molding process, the transmittance, chromatic aberration and impact resistance of the lens are ensured to meet industry standards.

[0039] 4. Optimize material properties

[0040] Enhanced weather resistance: Adding UV stabilizers and antioxidants improves the durability of the lens material in different environments and extends its service life.

[0041] Strong adaptability: By adjusting the material formula, lenses with different performances can be produced according to different market demands to meet diverse applications.

[0042] 5. Environmental benefits

[0043] Reduce resource waste: Efficient material utilization and production process reduce the consumption of raw materials and have less impact on the environment.

[0044] Reduce energy consumption: Optimized injection molding process and equipment utilization efficiency help reduce energy consumption and comply with the concept of sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a flow chart of the efficient injection molding process of headlight lenses based on multi-cavity molds. DETAILED DESCRIPTION

[0046] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with embodiments and drawings. The embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0047] Example 1: Polycarbonate headlight lens production

[0048] 1. Process parameters

[0049] Mould design: A 6-cavity mould was used, with the dimensions of each cavity being 150 mm in diameter and 3 mm in thickness.

[0050] Materials: 97.8% polycarbonate, containing 2% UV stabilizer and 0.2% antioxidant.

[0051] Injection pressure: 1000bar.

[0052] Injection speed: 60cm / s.

[0053] Cooldown time: 50 seconds.

[0054] Holding time: 10 seconds.

[0055] 2. Production process

[0056] The polycarbonate pellets were mixed with the additives and heated to 230°C in an injection molding machine.

[0057] The molten plastic is injected into the mold at the set injection pressure and speed.

[0058] After the mold has cooled, the mold is opened and the finished lens is taken out.

[0059] Optical performance testing showed that the transmittance reached 92%, the color difference ΔE was 0.4, and the impact strength was 15kJ / m 2 .

[0060] Example 2: Production of polymethyl methacrylate headlight lens

[0061] 1. Process parameters

[0062] Mould design: An 8-cavity mould was used, with each cavity measuring 130 mm in diameter and 4 mm in thickness.

[0063] Materials: 98.2 parts by weight of polymethyl methacrylate, 1.5 parts by weight of UV stabilizer and 0.3 parts by weight of antioxidant.

[0064] Injection pressure: 900bar.

[0065] Injection speed: 50cm / s.

[0066] Cooldown: 40 seconds.

[0067] Holding time: 8 seconds.

[0068] 2. Production process

[0069] The PMMA particles were uniformly mixed with the additives and heated to 230 °C in an injection molding machine.

[0070] Under the set injection parameters, the molten material is injected into the mold.

[0071] After cooling, the mold is opened and the lens is taken out.

[0072] After testing the finished product, the transmittance reached 90%, the color difference ΔE was 0.5, and the impact strength was 12kJ / m 2 .

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An efficient injection molding process for headlight lenses based on a multi-cavity mold, characterized in that: The following steps are involved: S1: mold design; Design an injection mold with multiple cavities, each of which can be independently injected with molten plastic, with 4-12 cavities; S2: Cooling system design; Multi-point cooling design: In the mold design, multiple cooling water channels are set up, and 2-4 cooling water channels are arranged around each cavity to ensure uniform cooling effect. The cooling water temperature is controlled between 10-15℃ to shorten the cooling cycle; Temperature monitoring system: Introduce temperature sensors to monitor mold temperature in real time, and set the temperature range to 60-80°C to ensure stability during the injection molding process; S3: Material selection and proportion; Select a plastic substrate with optical transparency and impact resistance, add 97-99 parts by mass of the plastic substrate, 1-3 parts by mass of a UV stabilizer and 0.1-0.3 parts by mass of an antioxidant in proportion, and mix thoroughly; S4: Injection molding parameters optimization; Injection pressure: Set the injection pressure in the range of 800-1200 bar to ensure that the molten plastic can fully fill the mold; Injection speed: Using variable speed injection technology, the initial injection speed is set at 50cm / s, and then gradually accelerated to reduce the shear stress of the melt and ensure uniform filling; Cooling time: The cooling time of the mold is optimized according to the thickness and size of the lens and is set to 40-60 seconds to ensure that the lens can cool quickly and maintain its shape after molding; Holding time: Set the holding time to 8-12 seconds to ensure that the product does not shrink or warp during the cooling process; S5: Quality monitoring; Optical performance testing: During the production process, optical testing equipment is used to monitor the transmittance and color difference of the lens to ensure that the lens transmittance is ≥90% and the color difference ΔE<1; Physical property testing: Regular sampling and testing of the physical properties of lenses, including impact strength and Vicat softening point, is performed according to ASTM D256 and ASTM D1525 standards to ensure that finished products meet industry standards.

2. The high-efficiency injection molding process for vehicle lamp lenses based on multi-cavity molds according to claim 1 is characterized in that: The mold material described in S1 is alloy steel H13 or P20.

3. The high-efficiency injection molding process for vehicle lamp lenses based on multi-cavity molds according to claim 1 is characterized in that: The inner surface of the mold described in S1 is mirror-polished, and the Ra value is controlled within 0.2 μm.

4. The high-efficiency injection molding process for vehicle lamp lenses based on multi-cavity molds according to claim 1 is characterized in that: The temperature sensor described in S2 is a thermocouple.

5. The high-efficiency injection molding process for vehicle lamp lenses based on multi-cavity molds according to claim 1 is characterized in that: The plastic substrate described in S3 is polycarbonate or polymethyl methacrylate.

6. The high-efficiency injection molding process for vehicle lamp lenses based on multi-cavity molds according to claim 1 is characterized in that: The UV stabilizer described in S3 is UV-328, and the antioxidant is BHT.

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