Aluminum-based LED support processing method

Abstract

The invention discloses an aluminum-based LED support machining method. The method comprises the following steps that S1, the surface of an aluminum base material is pretreated; s2, precise punch forming; s3, post-processing treatment is carried out; s4, electroplating pretreatment is carried out; s5, functional area plating layer preparation; and S6, online quality detection. Through the collaborative design of aluminum base material surface pretreatment and punching process optimization (adopting a diamond coating punch, adjusting the gap between the punch and the female die and high-pressure atomization cooling the punch), the formation of built-up edges in the aluminum material machining process is inhibited from the source, the tool sticking rate is reduced to 0.2% or below, the core problem of tool sticking in aluminum material machining is thoroughly solved, and the production efficiency is improved. And the stable and efficient mass production of the aluminum-based LED bracket is realized.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of LED packaging material processing, in particular to an aluminum-based LED support processing method. BACKGROUND

[0002] In the prior art, LED supports are mostly made of copper-based materials, because the copper material has excellent electrical conductivity and stable processing performance. However, the copper material is scarce, resulting in high cost, and the large density increases the overall weight of the LED device, which is not conducive to the lightweight design of the LED device and the terminal product. Compared with the copper-based material, the aluminum-based material has the advantages of small density (only 1 / 3 of that of copper), close electrical conductivity, low cost, and better heat dissipation performance. However, there is a serious technical bottleneck in the processing of the aluminum-based material. Because the aluminum has good ductility and continuous chips are easily generated during cutting, and the aluminum and the tool material are prone to chemical adhesion, the chips are adhered to the cutting edge of the tool to form a built-up edge, that is, the "adhesion" phenomenon. Not only does this increase the roughness of the processed surface and cause the size accuracy to be out of control, but it also causes the tool to wear quickly and even break, which cannot realize mass production, and this technical bottleneck limits the application of the aluminum-based material in the field of LED supports.

[0003] In the prior art, although there are attempts to use aluminum-based LED supports or plates, most of them focus on material formulations or post-film pasting processes. For example, patent CN115413134A discloses a production method for an aluminum-based film-coated plate for an LED, which focuses on the pasting and subsequent processing of the covering film, and does not fundamentally solve the problem of tool adhesion in the early precision forming process of the aluminum-based material. Patent CN209312790U discloses an LED support and an LED packaging structure, which mainly aims at the plating structure of the aluminum-based LED support, but does not involve the processing method of the aluminum-based material. Therefore, it is urgent to develop a processing method specifically for aluminum-based LED supports to solve the tool adhesion problem and realize mass production. SUMMARY

[0004] The purpose of the present application is to provide an aluminum-based LED support processing method to solve the tool adhesion problem in the processing of aluminum-based materials and realize batch and high-precision production of aluminum-based LED supports.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions: An aluminum-based LED support processing method, comprising the following steps: S1: surface pretreatment of the aluminum-based material: sequentially performing cleaning treatment, stress relief annealing, and chemical conversion film preparation on the aluminum alloy strip; S2: Precision stamping: Using a punch with an ultra-hard coating deposited on the cutting edge, the pre-treated aluminum alloy strip is continuously stamped on a high-speed CNC press using a stamping die to form an LED bracket array. During the stamping process, a high-pressure atomization cooling system applies a cooling and lubricating medium to the punch cutting edge. The high-speed CNC press is integrated with an online tool wear monitoring module, which detects the wear of the punch cutting edge in real time through a laser displacement sensor. An early warning is triggered when the wear exceeds 0.001mm. The superhard coating is a diamond coating (TA-C), with a coating thickness of 0.2-1μm, a hardness ≥5000HV, a friction system ≤0.1, a surface roughness Ra ≤0.05μm, and an operating temperature ≤450℃; S3: Post-processing: The processed aluminum substrate is subjected to ultrasonic cleaning, chromium-free passivation treatment and drying in sequence to obtain the aluminum-based LED bracket semi-finished product. S4: Pre-plating treatment: Plasma activation treatment is performed on the semi-finished aluminum-based LED bracket. S5: Functional area plating preparation: Copper plating underlayer, nickel plating transition layer and silver plating layer are sequentially deposited in the functional area of ​​the aluminum-based LED bracket semi-finished product to complete the aluminum-based LED bracket finished product processing; S6: Online quality inspection: A high-speed vision inspection system is used to conduct 100% inspection of the finished LED brackets, and products with excessive dimensional deviations and surface defects are rejected.

[0006] Furthermore, in step S1, the aluminum alloy strip is 6063 aluminum alloy, and the stress-relief annealing process is as follows: heating temperature 300-350℃, holding time 20-30min, and furnace cooling to room temperature; the chemical conversion film is a titanate film layer with a thickness of 0.5-1.5μm, treated by immersion in titanate conversion solution at a treatment temperature of 40-50℃ for 5-8min, with film adhesion ≥4B grade, and the pH value of the titanate conversion solution is 8.0-9.0, free of chloride and fluoride ion corrosive components.

[0007] Furthermore, in step S2, the single-sided gap between the punch and the die is 0.002-0.004 mm, and the stamping speed is controlled at 200-500 times / min; Furthermore, in step S2, the cooling and lubricating medium is an emulsion with a pH value of 8.5-9.5. The process parameters of the high-pressure atomization cooling system are: atomization injection pressure of 12-18MPa, atomization droplet size of 5-20μm, injection flow rate of 80-120ml / min, and equipped with a 5μm precision filtration circulation device to maintain the emulsion concentration of 5-8% in real time.

[0008] Further, in step S3, the ultrasonic cleaning process parameters are: frequency 40 kHz, cleaning liquid is deionized water solution containing 1-2 wt% neutral detergent, cleaning time 5-8 min, the chromium-free passivation treatment uses zirconium-titanium passivation solution, soaking temperature 25-35 DEG C, time 4-6 min, forming a thickness of 0.5-1 mu m dense passivation film, the drying process parameters are: temperature 80-100 DEG C, time 10-15 min.

[0009] Further, in step S4, the process parameters of the plasma activation treatment are: using mixed gas of argon and hydrogen, the volume ratio of argon and hydrogen is 9:1, the plasma power is 80-120 W, and the treatment time is 30-60 seconds.

[0010] Further, in step S5, the thickness of the copper plating bottom layer is 1-3 mu m, using acid sulfate copper plating process; the thickness of the nickel plating transition layer is 2-5 mu m, using semi-bright nickel plating process; the thickness of the silver plating layer is 0.5-2 mu m, using cyanide-free silver plating process.

[0011] Compared with the prior art, the beneficial effects of the present application are: 1. The present application cooperatively designs the surface pretreatment of the aluminum base material and optimizes the stamping process (uses diamond-coated punch, adjusts the gap between the punch and the concave die, and high-pressure atomization cooling punch), which inhibits the formation of burrs in the aluminum material processing process from the root, reduces the sticking rate to below 0.2%, and completely solves the core problem of aluminum material processing sticking, making the stable and efficient mass production of aluminum-based LED brackets a reality.

[0012] 2. The aluminum-based LED bracket produced by the present application has better product performance than traditional copper-based brackets and lower cost, has significant technical advantages, cost advantages and market application value. DETAILED DESCRIPTION

[0013] An embodiment provided by the present application: An aluminum-based LED bracket processing method, comprising the following steps: S1: surface pretreatment of aluminum base material: sequentially cleaning treatment, stress relief annealing and chemical conversion film preparation are performed on the aluminum alloy strip; S2: precision stamping forming: using a punch with superhard coating deposited on the cutting edge, the pretreated aluminum alloy strip is continuously stamped on a high-speed CNC punch using a stamping die, forming an LED bracket array, and a high-pressure atomization cooling system is used to apply cooling and lubricating medium to the cutting edge of the punch during the stamping process, the high-speed CNC punch is integrated with an online tool wear monitoring module, and the wear amount of the punch cutting edge is detected in real time by a laser displacement sensor, and a warning is triggered when the wear amount exceeds 0.001 mm. The superhard coating is a diamond coating (TA-C) with a thickness of 0.2-1 μm, a hardness of ≥5000 HV, a friction system of ≤0.1, a surface roughness Ra of ≤0.05 μm, and a working temperature of ≤450℃; By utilizing the high hardness and low friction coefficient of the diamond coating, the core pain point of "tool sticking" in the processing of aluminum base materials is directly solved, i.e., the chemical adhesion and mechanical engagement of aluminum chips and the cutting edge are reduced, the cutting resistance is reduced, and the aluminum material is fundamentally prevented from being welded on the cutting edge under high pressure shearing. Meanwhile, the high wear resistance of the diamond coating can also prolong the service life of the punch, reduce the frequency of mold replacement in batch production, ensure the surface smoothness of the stamping surface by the low surface roughness, and avoid the loss of dimensional accuracy; S3: processing post-treatment: the aluminum base material after processing is sequentially subjected to ultrasonic cleaning, chromium-free passivation treatment and drying to obtain an aluminum base LED support semi-finished product; S4: pre-plating treatment: the aluminum base LED support semi-finished product is subjected to plasma activation treatment; S5: functional area plating layer preparation: a copper bottom layer, a nickel transition layer and a silver layer are sequentially deposited on the functional area of the aluminum base LED support semi-finished product to complete the processing of the aluminum base LED support finished product. The functional area refers to the area on the LED support that is pre-set for mounting the LED chip.

[0014] S6: online quality detection: a high-speed visual detection system is used to conduct 100% full inspection on the LED support finished product to remove products with size deviation exceeding the standard and surface defects. The high-speed visual detection system can realize synchronous production and detection, avoid the flow of unqualified products into subsequent links, reduce the cost of rework, and record the detection data of each batch of products to facilitate quality tracing and process parameter optimization in batch production.

[0015] In step S1, the aluminum alloy strip is 6063 aluminum alloy.

[0016] The cleaning treatment removes impurities such as oil stains, oxide films and dust on the surface of the aluminum alloy strip to avoid the influence of impurities on the subsequent annealing, conversion film preparation and plating layer adhesion, and to provide a clean substrate surface for the subsequent process.

[0017] The stress relief annealing process is heating at a temperature of 300-350℃ for 20-30 min and cooling to room temperature in the furnace. Its role is to eliminate the internal stress generated in the rolling process of the aluminum alloy strip (rolling stress will cause local uneven deformation during stamping), make the internal structure of the substrate uniform and stable, avoid problems such as warping and dimensional deviation caused by stress release during stamping, and improve the dimensional consistency of batch production.

[0018] The chemical conversion film is a titanate film layer with a thickness of 0.5-1.5 μm, and is obtained by immersion treatment using a titanate conversion solution at a temperature of 40-50 °C for 5-8 min. The film layer has an adhesion of ≥4B grade, and the titanate conversion solution has a pH value of 8.0-9.0 and does not contain corrosive components such as chloride ions and fluoride ions.

[0019] The titanate film layer has both compactness and good toughness, can be closely attached to the surface of the aluminum alloy substrate and follow the plastic deformation of the substrate during stamping, effectively isolates the direct contact between the aluminum substrate and the punch blade, reduces the probability of chemical adhesion between the aluminum substrate and the tool material, and reduces the friction coefficient during stamping, thereby inhibiting the risk of chip adhesion to the blade to form a burr from the source, and ensuring the continuity and stability of the stamping process.

[0020] In step S2, the one-sided gap between the punch and the die is 0.002-0.004 mm, and the stamping speed is controlled at 200-500 times / min. By controlling the extremely small gap between the punch and the die, the aluminum material is precisely sheared and separated, the contact time with the blade is shortened, the friction area is reduced, the chips are in a sheet shape, and the chips are easily discharged to avoid accumulation and adhesion. At the same time, the local temperature rise and stress concentration of the blade are reduced, the adhesion of aluminum is inhibited, and the problem of tool adhesion is solved in cooperation with the super-hard coating and the cooling system. The stamping speed of 200-500 times / min can balance the production efficiency and processing stability, and meet the capacity demand of batch production.

[0021] In step S2, the cooling and lubricating medium is an emulsion with a pH value of 8.5-9.5, and the process parameters of the high-pressure atomizing cooling system are: atomizing injection pressure 12-18 MPa, atomizing droplet size 5-20 μm, injection flow rate 80-120 ml / min, and 5 μm precision filtration circulating device is matched, and the emulsion concentration is maintained at 5-8% in real time.

[0022] The cooling and lubricating medium has three functions: first, quickly remove a large amount of heat generated during stamping to avoid the softening of the aluminum substrate due to high temperature, and at the same time protect the TA-C coating to avoid overheating failure; second, the emulsion forms a continuous lubricating film between the punch blade and the substrate, further reduces the friction, and has a synergistic effect with the low adhesion property of the coating to maximize the prevention of aluminum adhesion; third, the high-pressure atomizing droplets impact the blade to timely remove the small chips and avoid surface scratches or size deviation caused by chip accumulation.

[0023] In step S3, the ultrasonic cleaning process parameters are: frequency 40 kHz, cleaning liquid is deionized water solution containing 1-2 wt% neutral detergent, and cleaning time is 5-8 min; the residual chips, emulsion, conversion film debris and other impurities on the surface of the support after stamping are removed to avoid the influence of the impurities on the formation of the subsequent passivation film and the adhesion of the plated layer, and at the same time ensure the cleanliness of the surface of the support.

[0024] The chromium-free passivation treatment adopts a zirconium-titanium passivation solution, the soaking temperature is 25-35°C, the time is 4-6 min, a dense passivation film with a thickness of 0.5-1 μm is formed, the air, moisture and other corrosive media are isolated, the corrosion resistance of the bracket is improved, at the same time, the active groups on the surface of the passivation film can form chemical bonding with the subsequent plating layer, and the adhesion of the plating layer is further enhanced.

[0025] The drying process parameters are: temperature 80-100°C, time 10-15 min. The water on the surface of the bracket is completely removed, the surface oxidation caused by water residue (such as water stains, rust spots) is avoided, and a dry surface environment is provided for the subsequent plating layer preparation, ensuring stable plating layer quality.

[0026] In step S4, the process parameters of the plasma activation treatment are: a mixed gas of argon and hydrogen is used, the volume ratio of the argon and hydrogen is 9:1, the plasma power is 80-120 W, and the treatment time is 30-60 seconds. Through the physical bombardment and chemical reduction of the plasma, the trace oxide film, passivation film residue and adsorbed impurities on the surface of the LED bracket are removed, the active sites are formed on the surface of the substrate, the adhesion of the subsequent plating layer and the substrate is improved, and the peeling and falling of the plating layer are avoided.

[0027] In step S5, the thickness of the copper bottom layer is 1-3 μm, the acid sulfate copper plating process is used; the thickness of the nickel transition layer is 2-5 μm, the semi-bright nickel plating process is used; the thickness of the silver layer is 0.5-2 μm, the cyanide-free silver plating process is used.

[0028] The copper bottom layer can fill the small scratches and pores on the surface of the substrate, making the subsequent plating layer more flat, at the same time, the copper layer has good compatibility with the aluminum substrate and the subsequent nickel layer, which can alleviate the lattice mismatch problem between aluminum and nickel, and enhance the overall adhesion of the plating layer; the nickel transition layer has high chemical stability, which can effectively block the diffusion of metal ions in the aluminum substrate to the surface silver layer (aluminum diffusion will cause the silver layer to turn black and the conductivity to decrease), prolonging the service life of the bracket, and also improving the adhesion of the silver plating layer; the silver layer is the core conductive layer, and the conductivity of silver is optimal, which meets the high conductivity demand of the functional area of the LED bracket.

[0029] Through testing, the aluminum-based LED bracket processed by the method has a smooth stamping process, the sticking rate is 0.2% (the sticking rate of the aluminum-based LED bracket processed by the traditional method is 15.8%), the product conductivity is 39.2 MS / m, which is better than the traditional copper-based bracket (35-37 MS / m), the heat dissipation efficiency is improved by 25-30%, the weight is about 50% lighter than the copper-based bracket, and the cost is about 30% lower than the copper-based bracket.

[0030] The above examples prove that the processing method of the application can effectively solve the problem of sticking tool in processing of the aluminum-based LED support, realize batch and high-precision production, the product performance is better than that of the traditional copper-based support and the cost is lower, and the application has significant technical advantages, cost advantages and market application value.

[0031] Although embodiments of the application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for processing an aluminum-based LED bracket, characterized in that, Includes the following steps: S1: Surface pretreatment of aluminum substrate: The aluminum alloy strip is sequentially cleaned, stress-relieving annealed, and chemical conversion film prepared. S2: Precision stamping: Using a punch with an ultra-hard coating deposited on the cutting edge, the pre-treated aluminum alloy strip is continuously stamped on a high-speed CNC press using a stamping die to form an LED bracket array. During the stamping process, a high-pressure atomization cooling system applies a cooling and lubricating medium to the punch cutting edge. The high-speed CNC press is integrated with an online tool wear monitoring module, which detects the wear of the punch cutting edge in real time through a laser displacement sensor. An early warning is triggered when the wear exceeds 0.001mm. The superhard coating is a diamond coating (TA-C), with a coating thickness of 0.2-1μm, a hardness ≥5000HV, a friction system ≤0.1, a surface roughness Ra ≤0.05μm, and an operating temperature ≤450℃; S3: Post-processing: The processed aluminum substrate is subjected to ultrasonic cleaning, chromium-free passivation treatment and drying in sequence to obtain the aluminum-based LED bracket semi-finished product. S4: Pre-plating treatment: Plasma activation treatment is performed on the semi-finished aluminum-based LED bracket. S5: Functional area plating preparation: Copper plating underlayer, nickel plating transition layer and silver plating layer are sequentially deposited in the functional area of ​​the aluminum-based LED bracket semi-finished product to complete the aluminum-based LED bracket finished product processing; S6: Online quality inspection: A high-speed vision inspection system is used to conduct 100% inspection of the finished LED brackets, and products with excessive dimensional deviations and surface defects are rejected.

2. The method for processing aluminum-based LED brackets according to claim 1, characterized in that: In step S1, the aluminum alloy strip is 6063 aluminum alloy, and the stress-relief annealing process is as follows: heating temperature 300-350℃, holding time 20-30min, and furnace cooling to room temperature; the chemical conversion film is a titanate film layer with a thickness of 0.5-1.5μm, treated by immersion in titanate conversion solution at a treatment temperature of 40-50℃ for 5-8min, with film adhesion ≥4B grade, and the pH value of the titanate conversion solution is 8.0-9.0, and it does not contain chloride or fluoride ions corrosive components.

3. The method for processing aluminum-based LED brackets according to claim 1, characterized in that: In step S2, the single-sided gap between the punch and the die is 0.002-0.004 mm, and the stamping speed is controlled at 200-500 times / min.

4. The method for processing aluminum-based LED brackets according to claim 1, characterized in that: In step S2, the cooling and lubricating medium is an emulsion with a pH value of 8.5-9.

5. The process parameters of the high-pressure atomization cooling system are: atomization injection pressure of 12-18MPa, atomization droplet size of 5-20μm, injection flow rate of 80-120ml / min, and equipped with a 5μm precision filtration circulation device to maintain the emulsion concentration of 5-8% in real time.

5. The method for processing aluminum-based LED brackets according to claim 1, characterized in that: In step S3, the ultrasonic cleaning process parameters are: frequency 40kHz, cleaning solution is a deionized aqueous solution containing 1-2wt% neutral detergent, cleaning time 5-8min, the chromium-free passivation treatment uses zirconium-titanium passivation solution, immersion temperature 25-35℃, time 4-6min, forming a dense passivation film with a thickness of 0.5-1μm, and the drying process parameters are: temperature 80-100℃, time 10-15min.

6. The method for processing aluminum-based LED brackets according to claim 1, characterized in that: In step S4, the process parameters for the plasma activation treatment are as follows: a mixed gas of argon and hydrogen is used, the volume ratio of argon to hydrogen is 9:1, the plasma power is 80-120W, and the treatment time is 30-60 seconds.

7. The method for processing aluminum-based LED brackets according to claim 1, characterized in that: In step S5, the thickness of the copper plating underlayer is 1-3 μm, and an acidic sulfate copper plating process is used; the thickness of the nickel plating transition layer is 2-5 μm, and a semi-bright nickel plating process is used; the thickness of the silver plating layer is 0.5-2 μm, and a cyanide-free silver plating process is used.