Consumer electronic shell double-color effect preparation process
By spraying colored paint onto the inside of a transparent plastic casing and then curing it, the high cost and complexity of the two-color injection molding process were solved, enabling the production of two-color effect casings for consumer electronics, reducing production costs and improving product qualification rates.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-11
- Publication Date
- 2026-04-03
AI Technical Summary
The existing two-color injection molding process has problems such as complex mold design, high cost, high equipment requirements and high production difficulty, which leads to increased production costs and high product scrap rate.
Using transparent plastic shell material and internal spraying process, colored paint is sprayed on the inside of the transparent shell and cured, replacing the traditional two-color injection molding process, and achieving the two-color effect using existing single-cavity molds and spraying equipment.
It reduces production costs by more than 60%, simplifies operation, and increases product qualification rate to over 98%. It is applicable to a variety of consumer electronics products and has the potential for large-scale application.
Smart Images
Figure CN121776090A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of plastic parts processing technology, and in particular to a process for preparing a two-color effect for consumer electronics casings. Background Technology
[0002] With the rapid development of the consumer electronics market, consumers have increasingly higher requirements for the appearance design of electronic products. Electronic devices with two-color and multi-color appearances are favored by consumers due to their strong visual layering and high aesthetic appeal. Currently, the mainstream process for achieving two-color effects on consumer electronic casings is two-color injection molding. This process requires the design of a dedicated two-color mold and the use of a two-color injection molding machine with rotation or displacement functions. Two different colors or materials of plastic are injected into the same mold cavity through two injection processes, thus forming a two-color effect product.
[0003] However, the existing two-color injection molding process has obvious shortcomings: on the one hand, the structure of two-color molds is complex, requiring precise matching of the size and position of the two cavities, and the mold manufacturing precision requirements are extremely high, which leads to a significant increase in mold development costs, usually 2 to 3 times that of ordinary single-cavity molds; on the other hand, the equipment investment for two-color injection molding machines is large, and the requirements for the production site and the technical level of operators are also high. Moreover, if problems such as cavity matching deviation occur during the production process, it is easy to cause product scrapping, which increases production costs. Summary of the Invention
[0004] To overcome the current market situation and production pain points, the purpose of this invention is to provide a simple and lower-cost manufacturing process for two-color effect on consumer electronic casings. The core of this technology lies in the combination of transparent plastic casing material and internal spraying process, in order to solve the problems of high cost, high production difficulty and complex process, and high equipment requirements of existing two-color injection molding processes, and meet the needs of large-scale market applications.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] This invention provides a process for preparing a two-color effect for consumer electronics casings, comprising the following steps:
[0007] (1) Transparent shell pretreatment: Clean the inner surface of the transparent consumer electronics shell;
[0008] (2) Inner side spraying and coloring: Determine the color of the paint to be sprayed according to the product appearance design, and spray the inner surface of the pre-treated consumer electronic shell to form a colored paint layer with the desired color effect.
[0009] (3) Curing and molding: The finished consumer electronic casing is dried and cured at a temperature of 60℃~80℃ for 15min~20min, and then cooled to room temperature to obtain a consumer electronic casing with a two-color effect.
[0010] This invention uses a finished transparent shell as a base and achieves a two-color effect through precise inner spraying and curing, replacing the traditional two-injection process of two-color mold injection molding. This fundamentally simplifies the process and saves costs. Furthermore, existing single-cavity transparent shell molds and conventional spraying equipment can be directly reused to implement this invention's process, avoiding the high investment in two-color molds and dedicated injection molding machines. There is no need to develop two-color molds; existing equipment is used to achieve the two-color effect, thus providing advantages in cost and yield rate.
[0011] In some specific technical solutions of the present invention, the material of the consumer electronics casing includes any one of polycarbonate (PC), polymethyl methacrylate (PMMA), and PC / ABS alloy.
[0012] As an example, consumer electronics casings can be transparent casings such as PMMA transparent fast charger casings, PC / TPU composite transparent shockproof phone casings, PC transparent wireless charging decorative panels, and PC / ABS alloy transparent power bank casings.
[0013] In some specific technical solutions of the present invention, the cleaning process is as follows: first, use a lint-free cloth soaked in 70%~95% medical alcohol to wipe the inner surface of the consumer electronic casing at a speed of 5cm / s~15cm / s to remove oil stains and surface impurities; then, rinse with deionized water; and finally, perform hot air drying to ensure that there is no moisture residue on the inner surface of the consumer electronic casing.
[0014] Preferably, the water pressure for the spray rinsing is 0.1MPa~0.3MPa, the water temperature is 20℃~30℃, and the spray rinsing time is 5s~15s.
[0015] Preferably, the hot air velocity for the hot air drying process is set to 1.5 m / s to 2.5 m / s, the hot air temperature is set to 40℃ to 50℃, and the drying time is 5 min to 8 min.
[0016] In some specific technical solutions of the present invention, the paint layer covers the entire inner cavity surface of the consumer electronics casing or only covers a portion of the inner cavity surface of the consumer electronics casing.
[0017] Specifically, the pre-treated consumer electronics casing is first fitted into the masking fixture; then, a miniature automatic hanger is used to secure the casing to the masking fixture and attach it to the painting line. The miniature automatic hanger has a single-point connection to the top of the consumer electronics casing, with a contact area ≤0.3cm². 2The inner side of the consumer electronics casing, where the area to be sprayed is distributed upwards and vertically aligned with the spray gun.
[0018] The material of the spray masking clamp can be any one of silicone, ABS, or PP.
[0019] In some specific technical solutions of this invention, the spraying operation employs automated spraying equipment. The pre-drawn three-dimensional model data of the consumer electronics casing is imported into the control system of the automated spraying equipment, and a spraying path is set. This allows the spray gun to perform a uniform spraying operation along the preset path on the inner surface of the consumer electronics casing. This invention controls the automated spraying path based on three-dimensional model data, achieving flexible adaptation to partial / overall spraying and solving the problem of monotonous appearance in traditional processes.
[0020] Preferably, the paint layer is made by mixing acrylic paint and thinner in a mass ratio of (2~4):1, and the viscosity is 14s~18s (Ford cup 4, 25°C).
[0021] As an example, acrylic paint includes any one of blue acrylic paint, gradient purple acrylic paint, gradient blue acrylic paint, and matte gray acrylic paint.
[0022] Preferably, the parameters for spraying the paint layer are set as follows: spraying pressure of 0.2MPa~0.6MPa, spraying distance of 10cm~25cm, moving speed of 2cm / s~10cm / s, and paint layer thickness of 8μm~12μm. This spraying pressure range ensures uniform paint adhesion without generating excessive paint mist; this spraying distance range avoids paint accumulation due to excessively close distance or uneven coating due to excessively long distance.
[0023] In some specific technical solutions of this invention, the drying and curing process involves drying the painted consumer electronics casing in a segmented drying oven at varying temperatures. The temperature of the first segment is 60℃~68℃, and the drying time is 5min~6min. The temperature of the second segment is 65℃~75℃, and the drying time is 7min~8min. The temperature of the third segment is 60℃~68℃, and the drying time is 4min~6min. Using a segmented drying oven for segmented heating and drying facilitates controllable curing. Within this process parameter range, both rapid curing of the paint and prevention of deformation of the transparent casing due to excessively high temperatures are ensured.
[0024] In some improved technical solutions of the present invention, the casing of consumer electronics is first subjected to preheating treatment and gas electrostatic dust removal treatment before spraying to form a paint layer.
[0025] Preferably, the preheating process includes sending the consumer electronics casing into a preheating furnace for preheating for 1 min to 3 min, with the hot air velocity in the preheating furnace set to 1 m / s to 2 m / s and the preheating temperature set to 45℃ to 55℃.
[0026] Preferably, the gas electrostatic dust removal process includes sending the consumer electronics casing into a gas electrostatic dust removal chamber for dust removal. The operating parameters of the gas electrostatic dust removal chamber are set as follows: the compressed air pressure is 0.2MPa~0.5MPa, the nozzle distance from the consumer electronics casing is 10cm~20cm, the spray gun moving speed is 3cm / s~5cm / s, the voltage of the electrostatic eliminator is 6kV~10kV, and the elimination time is 1s~3s.
[0027] In some improved technical solutions of the present invention, a topcoat layer for reinforcement is formed 20s to 25s after the color paint layer is formed by spraying.
[0028] Preferably, the paint in the topcoat layer is a mixture of a translucent topcoat and a thinner in a mass ratio of (2~4):1, with a viscosity of 16s~20s (Ford Cup 4, 25°C).
[0029] As an example, translucent topcoat includes any one of high-transparency acrylic topcoat, anti-fingerprint transparent topcoat, and high-transparency polyurethane paint.
[0030] Preferably, the spraying parameters for the topcoat layer are set as follows: spraying pressure of 0.2MPa~0.4MPa, spraying distance of 15cm~25cm, spray gun moving speed of 2cm / s~8cm / s, and topcoat layer thickness of 2μm~8μm.
[0031] Compared with existing technologies, this invention provides a process for preparing a two-color effect for consumer electronics casings, which has the following advantages:
[0032] (1) Production costs are significantly reduced: This invention directly utilizes existing transparent shell production molds and conventional spraying equipment, eliminating the need to develop complex two-color molds and purchase expensive two-color injection molding machines, thus reducing equipment investment costs by more than 60%; at the same time, the process is simplified, reducing costs for mold debugging, equipment maintenance, and other aspects, resulting in a 40% to 50% reduction in the overall production cost of the product.
[0033] (2) The production process is simple and easy to operate: Based on the finished transparent shell, the core process only includes three steps: pretreatment, spray painting and curing. The operation is simple and ordinary operators can be trained and start working. This solves the problem that the existing two-color mold process requires high technical personnel.
[0034] (3) High product qualification rate: The present invention achieves precise positioning of the transparent shell through special fixtures, and controls the spraying path and thickness by combining automated spraying equipment, which effectively avoids the product scrapping problem caused by cavity matching deviation in the existing two-color mold process, and the product qualification rate can be increased to more than 98%.
[0035] (4) Wide range of applications: This invention can be applied to the processing of various consumer electronic casings such as mobile phones, tablets, smartwatches, and headphones. The spraying color and coverage area can be flexibly adjusted according to design requirements, which can meet diverse market demands and has the prospect of large-scale promotion and application. Attached Figure Description
[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0037] Figure 1 Before and after photos of products with a dual-color visual effect prepared using the process of this invention. Detailed Implementation
[0038] The technical solution of the present invention will be clearly and completely described below through detailed embodiments and in conjunction with the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0039] Unless otherwise specified, the experimental methods used in the examples and comparative examples are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.
[0040] Example 1
[0041] This embodiment provides a process for preparing a two-tone effect for consumer electronics casings. Using a PC / ABS alloy transparent power bank casing as the processing object, a power bank casing with a matte gray inner side and a transparent outer side is prepared.
[0042] Material Selection Specifications: The consumer electronics casing is made of PC / ABS alloy transparent power bank casing (model: CAB-300, dimensions: 100mm long, 60mm wide, 20mm high, wall thickness 1.8mm, light transmittance 87%, impact resistance 15kJ / m²). 2The acrylic paint used is matte gray acrylic paint (model: AC-M201, solid content 43%, gloss ≤10°, adhesion grade 1); the thinner used is PC / ABS special environmentally friendly thinner (model: XC-301, evaporation rate 1.1cm / s); the masking clamp is a custom-made PP clamp with a positioning accuracy of ±0.02mm, avoiding the charging interface and indicator light hole on the outer shell.
[0043] The specific steps are as follows:
[0044] Step S1, Pre-treatment of the power bank casing:
[0045] A transparent power bank casing (made of PC / ABS alloy) of matching size for a 10000mAh capacity was selected, and the inner surface of the power bank casing was cleaned. The cleaning process was as follows: First, a lint-free cloth soaked in 75% medical alcohol was used to wipe the inner surface along the texture at a speed of 12cm / s in one direction, focusing on cleaning the area reserved inside the charging port; then, it was sprayed and rinsed with high-pressure deionized water (water pressure 0.22MPa, water temperature 25℃, spray rinsing time 10s); after that, it was sent to a hot air drying device for hot air drying (hot air speed set to 2m / s, hot air temperature set to 43℃, drying time 6min) to ensure that there was no moisture residue on the inner surface of the power bank casing.
[0046] Step S2, Inner side spraying and coloring:
[0047] Determine the color of the paint to be sprayed according to the product appearance design. Mix the matte gray acrylic paint and thinner at a mass ratio of 5:2. Stir with an electric mixer at a speed of 350r / min for 3min. Let stand for 8min to defoam. Measure the viscosity with a Forte 4 cup viscometer (25℃) and adjust it to 16s to obtain the paint used to form the paint layer for spraying.
[0048] The spraying operation uses automated spraying equipment. First, the pre-treated power bank shell is fitted into a PP material masking clamp. The positioning protrusion of the masking clamp is precisely fitted with the heat dissipation holes on the outside of the power bank shell to achieve precise positioning and ensure that the inner surface remains horizontal. The masking area includes the inner area corresponding to the charging port and indicator light. Then, a miniature automatic hanger is used to fix the power bank shell fitted with the masking clamp and hang the spraying line. The inner area of the power bank shell to be sprayed is horizontally distributed with the spray gun facing upwards.
[0049] The pre-drawn 3D model data of the power bank shell is imported into the control system of the automated spray painting equipment. The spraying path is set to cover the entire surface except for the inner area corresponding to the charging interface and indicator light hole. The equipment is started to perform uniform spraying operation (spraying pressure is 0.45MPa, spraying distance is 19cm, and spray gun moving speed is 9cm / s) to form a 11μm thick paint layer with a matte gray effect.
[0050] Step S3, Curing and Molding:
[0051] The painted power bank casing, along with its fixture, is fed into a segmented drying oven for segmented heating and drying (oven pressure 5 kPa). The first segment is at 65°C and dries for 5 minutes; the second segment is at 75°C and dries for 7 minutes; and the third segment is at 68°C and dries for 4 minutes, ensuring a strong bond between the paint layer and the power bank casing. After curing, the casing is removed and allowed to cool naturally to room temperature (12 minutes, 25°C), resulting in a power bank casing with a two-tone effect.
[0052] Step S4, Offline Inspection:
[0053] The appearance inspection showed no drips or color differences in the matte gray area, and the edges of the charging port reserved position were neat; the performance inspection showed that the adhesion reached GB / T 9286-1998 level 1, the paint layer did not peel off after the impact resistance test, the clarity of the light-transmitting outer indicator area was ≥90%, and the pass rate was 99.1%.
[0054] Example 2
[0055] This embodiment provides a process for preparing a two-color effect for consumer electronics casings. Using a transparent PC wireless charging decorative panel as the processing object, a wireless charging decorative panel with a gradient blue inner side and a transparent outer side with a two-color effect is prepared.
[0056] Material Selection Notes: The consumer electronics casing uses a transparent PC wireless charging decorative panel, model PC-110R, with dimensions of 90mm (length) x 90mm (width) x 3mm (height), a light transmittance of 90%, and a dielectric constant of 3.2, which does not affect wireless charging efficiency; the acrylic paint used is gradient blue acrylic paint (model: AC-G603, gradient transition width 30mm); the translucent topcoat uses high-transmittance polyurethane paint (model: PU-400, light transmittance 94%); the thinner used is PC / TPU dedicated thinner, model XC-205, with a moderate evaporation rate and no risk of material corrosion; the spray masking clamp is made of silicone material and avoids the area corresponding to the wireless charging coil.
[0057] The specific steps are as follows:
[0058] Step S1, Pre-processing of the wireless charging decorative panel:
[0059] Select a wireless charging decorative panel (made of PC) and clean its surface. The cleaning process is as follows: First, wipe the inner surface with a lint-free cloth soaked in 75% medical alcohol at a speed of 8 cm / s; then, spray and rinse with high-pressure deionized water (water pressure 0.15 MPa, water temperature 23℃, spray and rinse time 8s); finally, place it in a hot air drying device for hot air drying (hot air velocity set to 1.8 m / s, hot air temperature set to 42℃, drying time 5 min) to ensure that the surface of the wireless charging decorative panel is free of moisture.
[0060] Step S2, Inner side spraying and coloring:
[0061] Determine the color of the paint to be sprayed according to the product appearance design. Mix the gradient blue acrylic paint and thinner at a mass ratio of 5:2. Stir with an electric mixer at a speed of 300r / min for 2 minutes. Let stand for 5 minutes to defoam. Measure the viscosity with a Forte 4 cup viscometer (25℃) and adjust it to 18s to obtain the paint used to form the color paint layer for spraying.
[0062] The spraying operation uses automated spraying equipment. First, the pre-treated wireless charging decorative panel is put into a silicone masking clamp, and the masking area includes the wireless charging coil area. Then, a miniature automatic hanger is used to fix the wireless charging decorative panel with the masking clamp in place and hang the spraying line to ensure that the inner side of the wireless charging decorative panel to be sprayed is facing upwards, horizontally distributed, and vertically aligned with the spray gun.
[0063] The pre-drawn 3D model data of the wireless charging decorative panel is imported into the control system of the automated spray painting equipment. The gradient spraying path is set from the center to the edge (the color changes from light blue to dark blue). The equipment is started to carry out a dual-spray gun coordinated uniform speed spraying operation (the spraying pressure of the main spray gun is 0.4MPa, the spraying pressure of the auxiliary spray gun is 0.35MPa, the spraying distance is 20cm, and the spray gun moving speed is 7cm / s). The main spray gun is responsible for laying the base color, and the auxiliary spray gun is responsible for the gradient transition, forming a 12μm thick paint layer with a gradient blue effect.
[0064] Step S3, Topcoat reinforcement:
[0065] After the colored paint layer is formed for 25 seconds, the topcoat spraying process is started to form a topcoat layer for reinforcement.
[0066] The topcoat layer consists of a mixture of high-transmittance polyurethane paint and thinner at a mass ratio of 3:1, with the viscosity adjusted to 19s (Ford cup 4, 25℃). The spraying parameters for the topcoat layer are set as follows: spraying pressure of 0.36MPa, spraying distance of 23cm, spray gun movement speed of 6cm / s, one coat to fully cover the inner color paint layer, and a topcoat layer thickness of 5μm.
[0067] Step S4, Curing and Molding:
[0068] The painted wireless charging decorative panel, along with its fixture, is fed into a segmented drying oven for segmented heating and drying (air velocity 1.5 m / s, pressure 4 kPa). The first segment is dried at 68℃ for 5 minutes, the second segment at 72℃ for 8 minutes, and the third segment at 65℃ for 4 minutes. This process ensures a strong bond between the paint layer, the topcoat layer, and the wireless charging decorative panel itself. After curing, the panel is removed and allowed to cool naturally to room temperature (15 minutes, 25℃) to obtain a wireless charging decorative panel with a two-tone effect.
[0069] Step S5, Offline Inspection:
[0070] After removing the fixture, a full range of tests were conducted. The gradient blue on the inner side was natural, the light transmittance of the wireless charging area was ≥88%, the charging efficiency decay was ≤2%, the adhesion met GB / T 9286-1998 Grade 1, and the pass rate was 99.2%.
[0071] Example 3
[0072] This embodiment provides a process for preparing a dual-color effect for consumer electronic casings. Using a PC / TPU composite transparent shockproof phone case as the processing object, a shockproof phone case with a gradient purple inner side and a transparent outer side is prepared.
[0073] Material Selection Specifications: The consumer electronics casing uses a transparent, shockproof PC / TPU composite material, model CP-500. The PC hard shell layer is 1.2mm thick, and the TPU soft edge shockproof layer is 2mm thick. The overall dimensions are 162mm long, 78mm wide, and 11mm high, with a light transmittance of 89%. The acrylic paint used is gradient purple acrylic paint (model: AC-G601, solid content 46%, color difference ΔE≤0.6, natural gradient transition). The translucent topcoat uses anti-fingerprint transparent paint (model: AF-700, contact angle ≥110°, fingerprint resistance level 1). The thinner used is a PC / TPU-specific thinner, model XC-205, with a moderate evaporation rate and no risk of material corrosion. The spray masking clamp is made of ABS material.
[0074] The specific steps are as follows:
[0075] Step S1, Pre-treatment of the shockproof phone case:
[0076] A shockproof phone case (made of PC / TPU composite material) matching the size of a mainstream phone model was selected, and its surface was cleaned. The cleaning process involved: first, wiping the inner surface with a lint-free cloth soaked in 75% medical alcohol at a speed of 8 cm / s (focusing on cleaning the seams between the TPU soft edges and the PC hard shell) to remove residual mold release agent; then, spraying and rinsing with high-pressure deionized water (water pressure 0.18 MPa, water temperature 24℃, spraying and rinsing time 12s); finally, placing it in a hot air drying device for hot air drying (hot air velocity set to 1.8 m / s, hot air temperature set to 42℃, drying time 7 min) to ensure the inner surface of the shockproof phone case was free of moisture and impurities, and that the seams were thoroughly dry.
[0077] Step S2, Inner side spraying and coloring:
[0078] Determine the color of the paint to be sprayed according to the product appearance design. Mix the gradient purple acrylic paint and thinner at a mass ratio of 5:2. Stir with an electric mixer at a speed of 300r / min for 2 minutes. Let stand for 5 minutes to defoam. Measure the viscosity with a Forte 4 cup viscometer (25℃) and adjust it to 17s to obtain the paint used to form the colored paint layer for spraying.
[0079] The spraying operation uses automated spraying equipment. First, the pre-treated shockproof phone case is put into an ABS material masking clamp. The positioning protrusion of the masking clamp is precisely matched with the camera hole and button position on the outside of the shockproof phone case, with a positioning deviation of ≤0.03mm. The masking area includes the inner area corresponding to the camera hole and button position. Then, a miniature automatic hanger is used to fix the shockproof phone case with the masking clamp in place and hang the spraying line to ensure that the inner area to be sprayed on the shockproof phone case is facing upward, horizontally distributed, and vertically aligned with the spray gun.
[0080] The pre-drawn 3D model data of the shockproof phone case is imported into the control system of the automated spray painting equipment. The gradient spraying path is set from the bottom to the top of the phone case (the color gradually changes from dark purple to light purple, with a transition area width of 40mm). The equipment is started to perform a dual-spray gun coordinated uniform speed spraying operation (the spraying pressure of the main spray gun is 0.42MPa, the spraying pressure of the auxiliary spray gun is 0.38MPa, the spraying distance is 21cm, and the spray gun moving speed is 7cm / s). The main spray gun is responsible for laying the base color, and the auxiliary spray gun is responsible for the gradient transition, forming a 12μm thick paint layer with a gradient purple effect.
[0081] Step S3, Topcoat reinforcement:
[0082] After the colored paint layer is formed for 25 seconds, the topcoat spraying process is started to form a topcoat layer for reinforcement.
[0083] The topcoat layer consists of an anti-fingerprint transparent topcoat and a thinner mixed at a mass ratio of 3:1, with the viscosity adjusted to 19s (Ford Cup 4, 25℃). The spraying parameters for the topcoat layer are set as follows: spraying pressure of 0.36MPa, spraying distance of 23cm, spray gun movement speed of 6cm / s, one coat to fully cover the inner color paint layer, and a topcoat layer thickness of 5μm.
[0084] Step S4, Curing and Molding:
[0085] The coated and colored shockproof phone case, along with its fixture, is fed into a segmented drying oven for segmented heating and drying (air velocity 1.5 m / s, pressure 4 kPa). The first segment is at 68℃ and takes 5 minutes to dry; the second segment is at 72℃ and takes 8 minutes to dry; and the third segment is at 65℃ and takes 4 minutes to dry. This process ensures a strong bond between the paint layer, the topcoat layer, and the phone case itself. After curing, the case is removed and allowed to cool naturally to room temperature (15 minutes, 25℃). The TPU soft edge performance remains unchanged, resulting in a shockproof phone case with a two-tone effect.
[0086] Step S5, Offline Inspection:
[0087] After removing the fixtures, a full range of tests were conducted.
[0088] In terms of appearance: the gradient purple on the inside is natural and there are no obvious color gradations. The edges of the button reservation positions are neat and the deviation is ≤0.1mm.
[0089] In terms of performance: the adhesion test using the cross-cut test method meets the GB / T 9286-1998 Class 1 standard; the abrasion resistance test (load 500g, cotton cloth rubbing 500 times) shows no paint peeling or fading; the anti-fingerprint test shows no residue after water droplets roll off; the TPU soft edge shows no change in drop resistance.
[0090] It meets the requirements for use as a shockproof phone case.
[0091] Example 4
[0092] refer to Figure 1 This embodiment provides a process for preparing a dual-color effect for consumer electronic casings. Using a PMMA transparent fast charger casing as the processing object, a fast charger casing with a dual-color effect is prepared, featuring a partially blue inner side and a transparent outer side.
[0093] Material Selection Specifications: The consumer electronics casing uses a PMMA transparent fast charger casing, model PMMA-8N, with a light transmittance of 93% and dimensions of 42mm (L) x 42mm (W) x 30mm (H); the acrylic paint used is blue acrylic paint (model: AC-8802, solid content 42%, color difference ΔE ≤ 0.5); the translucent topcoat uses high-transmittance acrylic topcoat (model: AC-990, light transmittance 95%, weather resistance up to UV3000h); the thinner used is PMMA-specific thinner, model TH-103, with an evaporation rate of 1.2cm / s; the masking clamp is made of silicone (Shore hardness 50A, temperature resistance 120℃), and the masking area is the inner non-display area of the fast charger casing (area 200mm²). 2 ).
[0094] The specific steps are as follows:
[0095] Step S1, Pre-processing of the fast charger casing:
[0096] A fast charger shell (made of PMMA) was selected, and its surface was cleaned. The cleaning process involved: first, wiping the inner surface with a lint-free cloth soaked in 75% medical alcohol at a speed of 8 cm / s; then, rinsing with high-pressure deionized water (water pressure 0.15 MPa, water temperature 23℃, rinsing time 8 seconds); followed by hot air drying (hot air velocity set to 1.8 m / s, hot air temperature set to 40℃, drying time 8 minutes) to ensure the inner surface of the fast charger shell was free of moisture. The dried fast charger shell was then fitted into a silicone spray masking clamp, ensuring a 99% fit between the masked area and the fast charger shell without gaps.
[0097] Step S2, Installation of the spray painting line:
[0098] The fast charger casing, secured with a miniature automatic mounting bracket and spray masking clamp, is connected to the top of the fast charger casing at a single point (contact area ≤ 0.3cm²). 2 The inner side of the fast charger casing has a horizontally distributed area facing upwards and is vertically aligned with the spray gun.
[0099] Step S3, Preheating treatment:
[0100] The fast charger casing was placed into the preheating oven for 2 minutes. The hot air velocity in the preheating oven was set to 1.2 m / s, the preheating temperature was set to 55℃, and the surface temperature of the fast charger casing was stabilized at 45℃.
[0101] Step S4: Electrostatic dust removal treatment of gas:
[0102] The fast charger casing is sent into the gas electrostatic dust removal chamber for dust removal. The working parameters of the gas electrostatic dust removal chamber are set as follows: the compressed air pressure is 0.35MPa, the nozzle distance from the fast charger casing is 15cm, the moving speed is 4cm / s, the voltage of the electrostatic eliminator is 8kV, the elimination time is 1.5s, and the static electricity value on the surface of the fast charger casing is ≤80V.
[0103] Step S5: Inner side spraying and coloring:
[0104] Determine the color of the paint to be sprayed according to the product appearance design. Mix blue acrylic paint and thinner at a mass ratio of 3:1. Stir with an electric mixer at a speed of 300r / min for 2 minutes. Let stand for 5 minutes to defoam. Measure the viscosity with a Forte 4 cup viscometer (25℃). Adjust to 15s to obtain the paint used to form the paint layer for spraying.
[0105] The spraying operation uses a small automated spray gun (nozzle diameter 0.8mm). The equipment is started to carry out uniform spraying operation (spraying pressure is 0.3MPa, spraying distance is 15cm, and spray gun moving speed is 5cm / s). One spraying is used to cover only the inner non-masked area, forming a paint layer with a blue effect with a thickness of 8μm.
[0106] Step S6, Apply topcoat for reinforcement:
[0107] After the colored paint layer is formed for 20 seconds, the topcoat spraying process is started to form a topcoat layer for reinforcement.
[0108] The topcoat layer consists of a high-transmittance acrylic topcoat and a thinner mixed at a mass ratio of 2:1, with the viscosity adjusted to 18s (Ford Cup 4, 25℃). The spraying parameters for the topcoat layer are set as follows: spraying pressure of 0.28MPa, spraying distance of 16cm, spray gun movement speed of 4cm / s, one coat to fully cover the inner color paint layer, and a topcoat layer thickness of 5μm.
[0109] Step S7, Curing and Molding:
[0110] The painted fast charger casing, along with its fixture, is fed into a segmented drying oven for segmented heating and drying (air velocity 1.5 m / s, pressure 3 kPa). The first segment is dried at 60°C for 6 minutes, the second segment at 65°C for 8 minutes, and the third segment at 60°C for 6 minutes, ensuring a strong bond between the paint layer, topcoat layer, and the fast charger casing. After curing, the casing is removed and allowed to cool naturally to room temperature (12 minutes, 25°C), resulting in a fast charger casing with a two-tone effect.
[0111] Step S8, Offline Inspection:
[0112] After removing the fixture, the boundary deviation of the blue area was found to be ≤0.1mm, the coating adhesion reached GB / T 9286-1998 Grade 1, there was no haze in the light-transmitting area, the pass rate reached 99.5%, and the production cost of a single product was only about 1 yuan.
[0113] Comparative Example 1
[0114] This comparative example provides a process for manufacturing a two-color effect for consumer electronics casings, enabling the injection molding of two-color fast charger casings using traditional two-color molds.
[0115] Materials and Equipment Specifications: PC / ABS alloy (model: C1200HF) and blue PC material (model: PC-8002B) are selected; a two-color sliding mold is used (2 cavities, dimensional accuracy ±0.04mm, mold weight 3.2 tons); a two-color sliding injection molding machine is used (model: CJ200M3V, clamping force 2000kN, sliding distance 300mm).
[0116] The specific steps are as follows:
[0117] Step S1, Mold Preparation: Set the temperature of the first cavity (PC / ABS cavity) of the mold to 270℃, the temperature of the second cavity (blue PC cavity) to 265℃, the preheating time to 30min, and the mold closing pressure to 1800kN.
[0118] Step S2, First Injection Molding: Inject PC / ABS molten material into the first cavity. The injection temperature is 280℃, the injection pressure is 100MPa, the holding pressure is 80MPa, the holding time is 20s, and the cooling time is 25s to form a transparent base (dimensions: length 75mm, width 50mm, height 30mm).
[0119] Step S3, Cavity Translation: The transparent base along with the moving mold is translated to the second cavity by the translation mechanism of the injection molding machine. The translation speed is 50mm / s and the positioning deviation is ≤0.04mm.
[0120] Step S4, Second Injection Molding: Inject blue PC melt into the second cavity. The injection temperature is 275℃, the injection pressure is 90MPa, the holding pressure is 70MPa, the holding time is 18s, and the cooling time is 22s, forming a blue heat dissipation fin structure.
[0121] Step S5, Demolding and Inspection: Open the mold and remove the part, remove the main channel residue, and calibrate the dimensions of the heat dissipation fin area.
[0122] Effect and cost analysis: Local shrinkage marks (0.08mm depth) were found in the blue heat dissipation fin area, and the insulation resistance at the junction of the transparent substrate and the blue PC was 10MΩ (lower than 100MΩ in Example 4). The production cost of a single shell was about 2 yuan, the development cost of the two-color mold was about 100,000 yuan, the product qualification rate was 91.8%, the production efficiency was 35% lower than that of Example 4, and the production cost was twice as high.
[0123] The tests for Example 4 and Comparative Example 1 were performed, and the data were recorded as shown in Table 1.
[0124] Table 1, Test Results of Example 4 and Comparative Example 1
[0125] As shown in Table 1, the test results indicate that compared with the traditional two-color mold injection molding process, the process of this invention not only significantly reduces production costs and simplifies the production process, but also further improves product performance.
[0126] The above embodiments are merely illustrative of the concept and technical solution of the present invention and are not intended to limit the present invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.
[0127] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A process for fabricating a two-color effect on the casing of consumer electronics, characterized in that, Includes the following steps: (1) Transparent shell pretreatment: Clean the inner surface of the transparent consumer electronics shell; (2) Inner side spraying and coloring: Determine the color of the paint to be sprayed according to the product appearance design, and spray the inner surface of the pre-treated consumer electronic shell to form a colored paint layer with the desired color effect. (3) Curing and molding: The finished consumer electronic casing is dried and cured at a temperature of 60℃~80℃ for 15min~20min, and then cooled to room temperature to obtain a consumer electronic casing with a two-color effect.
2. The process for preparing a dual-color effect for consumer electronics casings according to claim 1, characterized in that, The material of the consumer electronics casing includes any one of polycarbonate, polymethyl methacrylate, and PC / ABS alloy.
3. The process for preparing a dual-color effect for consumer electronics casings according to claim 1, characterized in that, The cleaning process is as follows: First, use a lint-free cloth soaked in 70%~95% medical alcohol to wipe the inner surface of the consumer electronics casing at a speed of 5cm / s~15cm / s, then rinse with deionized water, and finally dry with hot air.
4. The process for preparing a dual-color effect for consumer electronics casings according to claim 3, characterized in that, The water pressure for the spray rinsing is 0.1MPa~0.3MPa, the water temperature is 20℃~30℃, and the spray rinsing time is 5s~15s; The hot air velocity for the hot air drying process is set to 1.5 m / s to 2.5 m / s, the hot air temperature is set to 40℃ to 50℃, and the drying time is 5 min to 8 min.
5. The process for preparing a dual-color effect for consumer electronics casings according to claim 1, characterized in that, The paint layer may cover the entire inner surface of the consumer electronics casing or only a portion of the inner surface of the consumer electronics casing.
6. The process for preparing a dual-color effect for consumer electronics casings according to claim 1, characterized in that, The spraying operation uses automated spraying equipment. The three-dimensional model data of the pre-drawn consumer electronics casing is imported into the control system of the automated spraying equipment, and the spraying path is set so that the spray gun performs uniform spraying operation on the inner surface of the consumer electronics casing along the preset spraying path. The paint layer is made by mixing acrylic paint and thinner in a mass ratio of (2~4):1, with a viscosity of 14s~18s. The parameters for the paint layer spraying operation are set as follows: spraying pressure is 0.2MPa~0.6MPa, spraying distance is 10cm~25cm, spray gun moving speed is 2cm / s~10cm / s, and paint layer thickness is 8μm~12μm.
7. The process for preparing a dual-color effect for consumer electronics casings according to claim 1, characterized in that, The drying and curing process involves drying the coated consumer electronics casing in a segmented drying oven at varying temperatures. The temperature of the first segment is 60℃~68℃, and the drying time is 5min~6min. The temperature of the second segment is 65℃~75℃, and the drying time is 7min~8min. The temperature of the third segment is 60℃~68℃, and the drying time is 4min~6min.
8. The process for preparing a dual-color effect for a consumer electronics casing according to any one of claims 1 to 7, characterized in that, Consumer electronics casings undergo preheating and electrostatic dust removal before being sprayed to form a paint layer. The preheating process includes sending the consumer electronics casing into a preheating furnace for 1 min to 3 min, with the hot air velocity in the preheating furnace set to 1 m / s to 2 m / s and the preheating temperature set to 45℃ to 55℃. The gas electrostatic dust removal process includes sending the consumer electronics casing into a gas electrostatic dust removal chamber for dust removal. The operating parameters of the gas electrostatic dust removal chamber are set as follows: the compressed air pressure is 0.2MPa~0.5MPa, the nozzle distance from the consumer electronics casing is 10cm~20cm, the moving speed is 3cm / s~5cm / s, the voltage of the electrostatic eliminator is 6kV~10kV, and the elimination time is 1s~3s.
9. The manufacturing process for a dual-color effect on a consumer electronics casing according to any one of claims 1 to 7, characterized in that, After the colored paint layer is formed by spraying for 20 to 25 seconds, a topcoat layer for reinforcement is sprayed.
10. The process for preparing a dual-color effect for consumer electronics casings according to claim 9, characterized in that, The paint in the topcoat layer is made by mixing a translucent topcoat and a thinner in a mass ratio of (2~4):1, with a viscosity of 16s~20s. The spraying parameters for the topcoat layer are set as follows: spraying pressure is 0.2MPa~0.4MPa, spraying distance is 15cm~25cm, spray gun moving speed is 2cm / s~8cm / s, and topcoat layer thickness is 2μm~8μm.