Double-color injection molding process for automobile lampshade

Abstract

The invention discloses a double-color injection molding process for an automobile lampshade, and aims to solve the problems of complex process, unstable quality, environmental pollution and the like in the process of realizing a multicolor effect through secondary processing of an existing single-color lampshade. According to the process, a cavity-divided mold design is adopted, a movable mold core is used for switching mold cavities, a primary color material and a cover color material are sequentially injected, and one-time forming of the double-color lampshade is achieved. Transparent polycarbonate is selected as a primary color material, opaque PC or PMMA is selected as a covering color material, and high optical performance and weather resistance are ensured. In the injection molding process, by optimizing process parameters of temperature, pressure, injection molding speed and cooling time, the defects of delamination, flow marks, bubbles and the like among materials are effectively avoided. And a mold runner adopts a balanced hot runner design, so that the material distribution uniformity is improved. The process achieves efficient production of the double-color lampshade, has the remarkable advantages of being excellent in product quality, low in production cost and environmentally friendly, and can be widely applied to the field of manufacturing of automobile lampshades.

Description

Technical Field

[0001] The invention relates to a two-color injection molding process for an automobile lampshade. Background Art

[0002] With the development of the automobile industry and the increasing requirements of consumers for vehicle appearance and functions, the design of automobile lampshades is becoming increasingly complex. They not only need to have excellent optical properties, but also need to meet the design requirements of multi-color splicing or gradient in appearance. At present, the traditional lampshade production method mainly adopts single-color injection molding, and then achieves multi-color effects through spraying, printing or secondary processing. However, this method has the following disadvantages:

[0003] Low production efficiency: multiple processes are required, which increases the production cycle;

[0004] Unstable product quality: secondary processing may result in insufficient color adhesion, easy to fall off or color difference;

[0005] Serious environmental pollution: A large amount of volatile organic compounds will be produced during the spraying process, which will cause harm to the environment and workers' health;

[0006] Higher cost: Additional processing steps increase labor costs and equipment investment.

[0007] Two-color injection molding technology can mold products with different colors or materials in one injection, eliminating the secondary processing step. However, due to the complex shape of automobile lampshades and the large differences in material properties, achieving high-quality two-color injection molding still faces many process challenges, such as: complex mold design, insufficient bonding strength of two-color materials, and flow marks or overflow problems during injection molding. Summary of the invention

[0008] The purpose of the present invention is to solve the above shortcomings of the prior art and provide a two-color injection molding process for an automobile lampshade with convenient connection.

[0009] The two-color injection molding process of the automobile lamp cover includes the following steps:

[0010] Step 1: Injection molding of base color material;

[0011] Injecting a transparent polycarbonate material into the first mold cavity to form a basic transparent part of the automobile lamp cover by injection molding; during the injection molding process, the temperature is controlled to be 180°C-220°C, the injection molding pressure is 80MPa-120MPa, and the injection molding speed is 15-30mm / s to ensure the optical properties and strength of the material;

[0012] Step 2: Mold core switching;

[0013] After the base color injection molding is completed, the mold structure is switched through the movable core or slider in the mold to transfer the lampshade base part to the second mold cavity, while closing the first mold cavity; the switching process uses precise positioning to ensure that all parts of the mold fit completely without gaps or misalignment;

[0014] Step 3: Injection molding of covering color material;

[0015] Inject opaque polycarbonate material or polymethyl methacrylate material into the second mold cavity to cover the designated area of ​​the base color part; during the injection molding process, control the temperature to 200℃-250℃, the injection pressure to 100MPa-140MPa, and the injection speed to 20-40mm / s to ensure close adhesion between the covering color and the base color material, while preventing uneven flow or overflow;

[0016] Step 4: Cooling and demoulding:

[0017] After completing the two-color injection molding, wait for the finished product to fully cool in the mold cavity for 20-40 seconds to ensure the dimensional stability of the product; use the automatic demoulding device to remove the two-color lampshade from the mold cavity; there should be no obvious seams, bubbles, flash or cracks on the product surface.

[0018] As a further improvement, the mold design includes a first mold cavity and a second mold cavity, which are used for molding the base color material and the covering color material respectively;

[0019] The mold core is a movable structure, driven by a hydraulic device or a servo motor to achieve rapid switching between the injection molding of the base color material and the injection molding of the covering color material;

[0020] The runner system adopts hot runner design and has balanced flow diversion function to ensure that the two-color material has no flow marks and stagnation during the injection molding process.

[0021] As a further improvement, the bonding area between the base color material and the covering color material is designed as a mechanical locking structure, and the surface where the materials are bonded has a micron-level roughness to increase the interface bonding strength of the materials; the bonding area is designed with grooves, serrations or interlocking structures to enhance the bonding strength and anti-fall-off performance of the two-color material.

[0022] As a further improvement, the cooling process uses a circulating water system or a coolant system built into the mold to improve cooling efficiency and reduce product cooling time.

[0023] As a further improvement, the injection molding machine adopts multiple control systems, which can independently control the temperature, pressure and injection time of the first mold cavity and the second mold cavity to meet the physical property requirements of different materials.

[0024] As a further improvement, the injection molding thickness of the covering color material is controlled between 0.5 mm and 2.0 mm to ensure the uniformity and durability of the covering color while maintaining the overall lightweight design of the lampshade.

[0025] As a further improvement, this process is suitable for complex lampshade designs, including the realization of multi-color gradients, two-color splicing and partial transparency effects.

[0026] As a further improvement, a vacuum assist system can be optionally used during the injection molding process to eliminate bubbles and improve the bonding quality of the two-color materials.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. One-step molding to reduce the number of processes

[0029] The two-color injection molding process enables the manufacture of multi-color lampshades through a set of molds and one-time molding, eliminating the need for secondary processing, significantly simplifying the production process and improving production efficiency.

[0030] 2. Improve product quality

[0031] Optimized mold design and precise process parameter control ensure close bonding between the two-color materials to avoid delamination, flow marks and bubbles;

[0032] The surface of the molded lampshade is smooth and the color is uniform, meeting the high-quality appearance requirements.

[0033] 3. Enhance material performance

[0034] Transparent PC is used as the base material to ensure that the lampshade has high light transmittance and impact resistance;

[0035] The covering color material has excellent weather resistance and wear resistance, ensuring the stable performance of the lampshade in long-term use.

[0036] 4. Environmentally friendly

[0037] The process avoids spraying and other secondary processing steps, reduces VOC emissions, and is environmentally friendly;

[0038] The injection molding material utilization rate is high, reducing waste.

[0039] 5. Adapt to complex design requirements

[0040] The process can meet the needs of complex lampshade design, including multi-color gradients, partial transparent areas and other functions, to meet the customization needs of different models.

[0041] 6. Save production costs

[0042] Reduce equipment investment and labor costs, shorten production cycle, and significantly reduce total production costs.

[0043] 7. Wide applicability

[0044] This process is suitable for lampshade designs with various complex shapes and high functional requirements, and has good market promotion value and industrialization prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is the flow chart of the two-color injection molding process of automobile lampshade; DETAILED DESCRIPTION

[0046] Example 1: Production process of two-color automobile lampshade

[0047] 1. Material Preparation

[0048] Base color material: transparent polycarbonate, its high light transmittance and impact resistance can meet the requirements of the optical and mechanical properties of the lampshade.

[0049] Covering color material: opaque PC or polymethyl methacrylate, with good weather resistance and decorative properties.

[0050] 2. Mold design

[0051] A two-color injection mold is used, which includes a first mold cavity and a second mold cavity. The first mold cavity is used for molding a base color material, and the second mold cavity is used for molding a covering color material.

[0052] The mold core is a movable structure, driven by a hydraulic or servo system, and transfers the base part of the lampshade to the second mold cavity after the base color molding is completed.

[0053] The runner adopts balanced hot runner design to ensure that the two-color material is evenly distributed during the injection molding process to avoid flow marks and stagnation.

[0054] 3. Injection molding process steps

[0055] Base color material injection molding

[0056] The transparent PC material is injected into the first mold cavity to form the basic shape of the lampshade through injection molding.

[0057] Injection molding process parameters:

[0058] Injection temperature: 190℃-220℃;

[0059] Injection pressure: 100MPa;

[0060] Injection speed: 20mm / s;

[0061] Holding time: 5 seconds;

[0062] Cooldown time: 15 seconds.

[0063] Ensure that the base color part has high optical properties, no bubbles, and no weld marks.

[0064] Mold core switching

[0065] After the base color molding is completed, the hydraulic system is started to drive the core to move, and the base body of the lampshade molded in the base color is transferred to the second mold cavity, and the first mold cavity is closed at the same time.

[0066] Ensure that there is no misalignment or offset during the movement of the core to avoid uneven bonding between the two-color materials.

[0067] Cover color material injection molding

[0068] Inject opaque PC or PMMA material into the second mold cavity to cover the designated area of ​​the base color material to form a two-color lampshade appearance.

[0069] Injection molding process parameters:

[0070] Injection temperature: 210℃-250℃;

[0071] Injection pressure: 120MPa;

[0072] Injection speed: 30mm / s;

[0073] Holding time: 10 seconds;

[0074] Cooldown: 20 seconds.

[0075] Ensure close bonding between the covering color material and the base color material, without delamination or cracks.

[0076] Cooling and demoulding

[0077] The molded two-color lampshade is fully cooled in the mold cavity, and the cooling process is accelerated by the built-in cooling water channel system.

[0078] After cooling is completed, start the automatic demoulding device and take out the lampshade.

[0079] 4. Product Inspection

[0080] Appearance inspection: There should be no color difference, flow marks and bubbles on the surface of the two-color lampshade, and there should be no obvious seams or overflow at the junction of the two colors.

[0081] Performance testing: Testing the light transmittance, impact resistance and weather resistance of the lampshade to ensure that it meets the quality standards of the automotive industry.

[0082] Embodiment 2: Production process of gradient two-color lampshade

[0083] This embodiment is improved on the basis of the embodiment 1, and is used to produce a two-color lampshade with a gradient effect.

[0084] Mold design

[0085] The second mold cavity is designed as a multi-section flow channel. During the injection molding process, the injection speed and pressure are dynamically controlled to achieve a gradient effect of the covering color material.

[0086] Process Control

[0087] The injection molding process of the base color material is the same as that of Example 1.

[0088] During the injection molding process of the covering color material, the injection speed (gradually increasing from 10 mm / s to 30 mm / s) and pressure (gradually increasing from 80 MPa to 120 MPa) are dynamically adjusted to achieve a gradual distribution of the material color.

[0089] Cooling and demoulding

[0090] The cooling time is appropriately extended to 25 seconds to ensure smooth material transition in the gradient area before demolding.

[0091] Precautions

[0092] The selection of two-color materials needs to consider the matching of thermoplasticity and adhesion to ensure the bonding strength of the two-color interface.

[0093] The moving speed and accuracy of the mold core must meet the product design requirements to avoid scrap caused by misalignment.

[0094] The flow channel design should ensure uniform material flow to avoid flow marks or bubbles affecting the appearance quality.

[0095] Through the above implementation methods, the present invention successfully solves the technical problems of complex mold design, insufficient bonding strength of two-color materials and appearance defects in the two-color lampshade molding process.

[0096] 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.

[0097] 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. The two-color injection molding process of automobile lampshade is characterized by: The following steps are involved: Step 1: Injection molding of base color material; Injecting a transparent polycarbonate material into the first mold cavity to form a basic transparent part of the automobile lamp cover by injection molding; during the injection molding process, the temperature is controlled to be 180°C-220°C, the injection molding pressure is 80MPa-120MPa, and the injection molding speed is 15-30mm / s to ensure the optical properties and strength of the material; Step 2: Mold core switching; After the base color injection molding is completed, the mold structure is switched through the movable core or slider in the mold to transfer the lampshade base part to the second mold cavity, while closing the first mold cavity; the switching process uses precise positioning to ensure that all parts of the mold fit completely without gaps or misalignment; Step 3: Injection molding of covering color material; Inject opaque polycarbonate material or polymethyl methacrylate material into the second mold cavity to cover the designated area of ​​the base color part; during the injection molding process, control the temperature to 200℃-250℃, the injection pressure to 100MPa-140MPa, and the injection speed to 20-40mm / s to ensure close adhesion between the covering color and the base color material, while preventing uneven flow or overflow; Step 4: Cooling and demoulding: After completing the two-color injection molding, wait for the finished product to fully cool in the mold cavity for 20-40 seconds to ensure the dimensional stability of the product; use the automatic demoulding device to remove the two-color lampshade from the mold cavity; there should be no obvious seams, bubbles, flash or cracks on the product surface.

2. The two-color injection molding process for automobile lampshade according to claim 1 is characterized in that: The mold design includes a first mold cavity and a second mold cavity, which are used for molding the base color material and the covering color material respectively; The mold core is a movable structure, driven by a hydraulic device or a servo motor to achieve rapid switching between the injection molding of the base color material and the injection molding of the covering color material; The runner system adopts hot runner design with balanced flow diversion function to ensure that the two-color material has no flow marks and stagnation during the injection molding process.

3. The two-color injection molding process for automobile lampshade according to claim 1 or 2, characterized in that: The bonding area between the base color material and the covering color material is designed as a mechanical locking structure, and the surface of the material bonding point has a micron-level roughness to increase the material interface bonding force; the bonding area is designed with grooves, serrations or interlocking structures to enhance the bonding strength and anti-shedding performance of the two-color material.

4. The two-color injection molding process for automobile lampshade according to claim 1 is characterized in that: The cooling process uses a circulating water system or a coolant system built into the mold to improve cooling efficiency and reduce product cooling time.

5. The two-color injection molding process for automobile lampshade according to claim 1 is characterized in that: The injection molding machine adopts multiple control systems, which can independently control the temperature, pressure and injection time of the first mold cavity and the second mold cavity to meet the physical property requirements of different materials.

6. The two-color injection molding process for automobile lampshade according to claim 1, characterized in that: The injection molding thickness of the covering color material is controlled between 0.5 mm and 2.0 mm to ensure the uniformity and durability of the covering color while maintaining the overall lightweight design of the lampshade.

7. The two-color injection molding process for automobile lampshade according to claim 1, characterized in that: This process is suitable for complex lampshade designs, including the realization of multi-color gradients, two-color splicing and partial transparent effects.

8. The two-color injection molding process for automobile lampshade according to claim 1, characterized in that: An optional vacuum assist system is available during the injection molding process to eliminate air bubbles and improve the bonding quality of the two-color materials.

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