Gap and surface difference control method for super-long vehicle lamp

Abstract

The invention relates to a clearance and surface difference control method for an overlength car lamp, which comprises the following steps of: optimizing a mold structure to improve the size of a lens, adjusting the injection molding process of the lens to control the weight of the lens, increasing the spraying annealing temperature of the lens, improving a buckling tool of a lamp shell and the lens and the like. And the problems of large gap, low surface difference, high customer complaint and the like frequently encountered in the production of the automobile lamp are successfully solved. Compared with other improvement modes, the method has the advantages of being simple, easy to implement, low in cost, good in effect and the like, the yield of defective products is greatly reduced, and meanwhile the economic benefits of enterprises are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle lamps, and in particular to a method for controlling the gap and flushness of an extra-long vehicle lamp. Background Art

[0002] With the advancement of technology and changes in consumer aesthetics, car light design is gradually developing towards multifunctionality and large-scale, and through-type lights are becoming more and more common. Compared with traditional car lights, through-type lights are longer in size, usually extending from one side of the car body to the other side.

[0003] Our company has specially developed and designed a front decorative lamp for a certain OEM. Its structure is as follows: Figure 1 As shown. The maximum horizontal length of the front decorative lamp is 986mm. Due to the long parts, the light distribution mirror, lamp housing, etc. are prone to quality problems. On the one hand, the front decorative lamp often has problems such as large gaps between the whole lamps and low surface difference during assembly, causing the finished lamps to be returned for repair, which not only affects the normal assembly production, but also causes complaints from production line operators and inspectors. Even if the qualified front decorative lamps are sent to the main engine factory for installation, they will still cause problems with the appearance of the installation due to large gaps between the whole lamps and low surface difference, causing customer complaints. How to solve these problems is imminent. Summary of the invention

[0004] The main purpose of the present invention is to solve the above-mentioned problems faced by this type of vehicle lamp and to provide a method for controlling the gap and flushness of an extra-long vehicle lamp, including: (a) optimizing the mold structure and improving the size of the light distribution mirror; (b) optimizing the injection molding process of the light distribution mirror; (c) optimizing the spraying and annealing process of the light distribution mirror; and (d) improving the fastening tooling between the lamp housing and the light distribution mirror.

[0005] Furthermore, the length of the extra-long headlight in the horizontal direction is ≥900 mm, and the aspect ratio is >6:1.

[0006] Furthermore, in step (a), the size of the lens is lengthened by modifying the mold, and the specific lengthening parts are the left and right sides of the lens in the length direction, and the lengthening range of one side does not exceed 1 mm.

[0007] Furthermore, in step (b), various injection molding parameters are adjusted to ensure that the weight of the lens is stable near the target value. By controlling the weight of the product, the size of the product is indirectly controlled.

[0008] Furthermore, in step (c), the spray annealing temperature of the photometric mirror is increased, and the placement of the photometric mirror in the annealing furnace is changed.

[0009] Furthermore, in step (c), the spray annealing temperature of the photometric mirror is increased to 120°C-130°C, preferably 123°C-125°C.

[0010] Furthermore, the placement of the light distribution mirror in the annealing furnace is changed from vertical free hanging to horizontal side placement with support at both ends.

[0011] Furthermore, in step (d), when the lamp housing and the light distribution lens are buckled together, positioning blocks are provided on the left and right sides of the length direction of the light distribution lens and at the middle logo position. Through these three positioning blocks, the light distribution lens and the lamp housing can be buckled together quickly and accurately, ensuring that the gap after the whole lamp is buckled is greatly reduced.

[0012] Compared with the prior art, the improved effects of the present invention are mainly reflected in the following aspects:

[0013] (1) Through in-depth analysis, it was determined that the light distribution mirror was the root cause of quality problems such as large gaps and low surface difference in the extra-long front decorative lights. Targeted improvements were made from multiple aspects, including the mold structure, injection molding process, spray annealing, and fastening tooling of the light distribution mirror. Each link was supported by corresponding data analysis, which promoted the optimization of product parts from the design stage. This was completely different from the traditional idea of ​​simply relying on adjusting injection molding process parameters for improvement;

[0014] (2) Compared with other improvement methods that have long cycles, high R&D costs, and uncontrollable risks, the present invention can solve the quality problem of ultra-long through-type headlights at a relatively low cost by simply making a series of relatively simple and easy-to-implement improvements and optimizations on the existing basis, greatly reducing the yield of defective products and improving the economic benefits of the enterprise;

[0015] (3) It provided experience for the company's later mold design and product design of whole lamp products above 900mm, and established a relevant database to ensure that the gap and surface difference of newly developed lamp products meet customer requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the front decorative lamp of the present invention;

[0017] Figure 2 This is the mold flow analysis result diagram of the light distribution mirror;

[0018] Figure 3 This is a schematic diagram of the left side extension of the photometric mirror;

[0019] Figure 4 This is the result of the injection weight analysis of the photometric mirror;

[0020] Figure 5 This is the placement diagram of the light distribution mirror in the annealing furnace;

[0021] Figure 6 This is the front view of the light distribution mirror and the lamp housing when they are buckled together;

[0022] Figure 7It is a side view of the light distribution mirror and the lamp housing when they are buckled together.

[0023] Description of the drawings: 1-light distribution mirror, 2-lamp housing, 3-left side of light distribution mirror, 4-right side of light distribution mirror, 5-logo base. DETAILED DESCRIPTION

[0024] In order to enable ordinary technicians in the field to fully understand the technical solutions and beneficial effects of the present invention, further description is given below in conjunction with specific embodiments and drawings.

[0025] like Figure 1 The front decorative lamp shown in the figure has a light distribution lens 1 on the front and a lamp housing 2 of similar shape on the back. The two are fixedly assembled together, and a logo base 5 is convexly provided in the middle of the light distribution lens. The lamp housing 2 is hidden inside the vehicle body and is an invisible part, while the light distribution lens 1 is exposed outside and is a visible part. Therefore, the appearance and assembly quality of the entire lamp is mainly determined by the light distribution lens 1.

[0026] The front decorative lamp is a through-type lamp with a maximum length of 986mm, a maximum width of 177mm, and an aspect ratio of about 6:1. Due to the long parts, the light distribution mirror obtained by injection molding according to the designed size often has gaps and surface differences during assembly. For this reason, we have made all-round improvements to the design and production of light distribution mirrors from multiple aspects, starting from mold structure, injection molding process, spray annealing, and fastening tooling, as follows:

[0027] (1) Analyze and improve the deformation of the photometric lens through mold flow analysis.

[0028] The mold flow analysis results of the light distribution mirror are as follows: Figure 2 As shown. Through mold flow analysis of the G6 point size, it is known that the deformation of the photometric lens G6 point is 0.7713. After analysis and discussion, it was decided to lengthen the left and right sides of the photometric lens. After mold flow analysis, it was finally found that the product size can meet the requirements. In order to reduce costs, it was decided to modify the original mold and lengthen the left and right sides of the photometric lens (i.e. Figure 1 The left side 3 of the photometric mirror and the right side 4 of the photometric mirror are lengthened by 0.7 mm respectively to meet the gap and face difference detection requirements of the whole lamp.

[0029] (2) Injection molding process optimization.

[0030] The original photometric lens injection molding process parameters (including barrel temperature, hot runner temperature, mold temperature, injection pressure, injection speed, injection position, holding pressure, holding speed, holding time, storage pressure, storage back pressure, storage speed, storage position, cycle time, and cooling time) are optimized.

[0031] Table 1 Comparison table of injection molding process parameters for photometric mirrors

[0032] project Optimization of the old injection molding process New injection molding process after optimization Barrel temperature, °C 295 295 Hot runner temperature, °C 305 305 Mold temperature, °C 90 90 Injection pressure, MPa 125，125，125 140，140，140，140 Injection speed, m / s 50，35，25 45，40，30，25 Injection position, mm 85，55，25 90，60，40，25 Holding pressure, MPa 20，20 20，20 Holding speed, m / s 70，65 70，65 Holding time, s 1.5，1.0 2.0，1.0 Storage pressure, MPa 150，150，150 150，150，150 Storage back pressure, MPa 10，10，10 10，10，10 Storage speed, m / s 25，30，25 25，30，20 Storage location, mm 40，70，110 40，70，110 Cycle time, s 85 85 Cooling time, s 33 35

[0033] In the later stage of mass production, the injection molding technicians adopted the optimized process parameters and tested the weight of the lens products to ensure the consistency of their dimensions. The weight of the lens products in different batches was weighed, and 125 groups (5 pieces / time) were selected each time for process capability analysis. The results are as follows: Figure 4 As shown in the figure, it can be seen that the weight of the photometric lens is controlled at 860±3g, PPK=1.44, and the process capability meets the requirements.

[0034] (3) Optimization of the spray annealing process of the light distribution mirror.

[0035] Through analysis and verification, it is determined that the spray annealing temperature of the photometric lens needs to be increased, as shown in Table 2. Based on this, the annealing furnace temperature is increased from the original 120℃ to between 123℃-125℃ to ensure that the annealing is sufficient and that there is no cracking or deformation of the parts after annealing.

[0036] Table 2 Test results of annealing process of light distribution mirror

[0037] time Annealing furnace conditions result August 23 120℃ / 120℃ / 120℃ / 120℃, 24HZ Microcracks September 3 123℃ / 123℃ / 123℃ / 123℃, 24HZ normal September 19 125℃ / 120℃ / 115℃ / 115℃, 35HZ Three pieces completely cracked September 19 125℃ / 125℃ / 120℃ / 120℃, 24HZ Two pieces without cracks September 20 130℃ / 125℃ / 120℃ / 120℃, 24HZ No cracks, 30 sets delivered without cracks October 9 130℃ / 130℃ / 125℃ / 125℃, 24HZ Five sets without cracks October 10 130℃ / 130℃ / 125℃ / 125℃, 24HZ No crack October 21 155℃ / 152℃ / 142℃ / 142℃, 24HZ Some small cracks October 22 157℃ / 154℃ / 144℃ / 144℃, 24HZ Slight deformation December 2 125℃ / 125℃ / 125℃ / 125℃, 20HZ Five sets without cracks December 2 125℃ / 125℃ / 125℃ / 125℃, 20HZ Four sets without cracks December 5 125℃ / 125℃ / 125℃ / 125℃, 20HZ Six sets without cracks December 6 125℃ / 125℃ / 125℃ / 125℃, 20HZ Fifty sets without cracks

[0038] The placement of the light distribution mirror in the annealing furnace was adjusted simultaneously, as follows: Figure 5 The photometric mirror was originally placed vertically on the conveyor chain of the annealing furnace. After optimization, it was changed to be placed horizontally in the annealing furnace, and the left and right sides of the photometric mirror were supported to ensure that it can be fully annealed in the annealing furnace to avoid cracking and deformation.

[0039] (4) Improve the fastening fixture between the lamp housing and the light distribution mirror.

[0040] The assembly process of the front decorative lamp also has a great impact on the gap and surface difference of the whole lamp. For this reason, we conducted a temporary verification on site. Add temporary positioning blocks ( Figure 6-7 The three positioning blocks are used to reduce the gap after the whole lamp is fastened together, thus improving the assembly quality of the product.

[0041] Through the above measures, the production, assembly and loading quality of front decorative lamp products were ultimately improved, which not only won the recognition of customers but also improved production efficiency.

Claims

1. A method for controlling the gap and flushness of an extra-long headlight. Features The method comprises: (a) optimizing the mold structure and improving the size of the photometric lens; (b) optimizing the injection molding process of the photometric lens; (c) optimizing the spraying annealing process of the photometric lens; and (d) improving the fastening tooling of the lamp housing and the photometric lens.

2. The method according to claim 1, Features: The length of the super-long headlight in the horizontal direction is ≥900mm, and the aspect ratio is >6:

1.

3. The method according to claim 1, Features: Step (a) lengthens the size of the lens by modifying the mold, and the specific lengthening parts are the left and right sides of the lens in the length direction, and the lengthening range of one side does not exceed 1mm.

4. The method according to claim 1, Features: In step (b), the weight of the photometric lens is controlled to remain stable by adjusting various injection molding parameters.

5. The method according to claim 1, Features: In step (c), the spray annealing temperature of the photometric mirror is increased, and the placement of the photometric mirror in the annealing furnace is changed.

6. The method according to claim 5, Features: In step (c), the spray annealing temperature of the photometric mirror is increased to 120°C-130°C.

7. The method according to claim 5, Features: The light distribution mirror is placed horizontally on its side in the annealing furnace and supported at both ends.

8. The method according to claim 1, Features: When the lamp housing and the photometric lens are buckled in step (d), positioning blocks are provided on both sides and in the middle of the length direction of the photometric lens.

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